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Solar heating of integrated greenhouse-animal shelter systems Ben-Abdallah, Noureddine 1983

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SOLAR HEATING OF INTEGRATED GREENHOUSE-ANIMAL SHELTER SYSTEMS BY NOUREDDINE BEN-ABDALLAH  B.^Sc. Texas A & M U n i v e r s i t y , 1969 M.A.Sc. The U n i v e r s i t y o f B r i t i s h Columbia, 1974 A T h e s i s submitted i n p a r t i a l f u l f i l m e n t of t h e r e q u i r e m e n t s f o r t h e degree o f Doctor o f P h i l o s o p h y (Interdisciplinary)  We accept t h i s t h e s i s as conforming t o t h e r e q u i r e d s t a n d a r d  THE. UNIVERSITY OF BRITISH COLUMBIA SEPTEMBER, 1983  0  N. B e n - A b d a l l a h .  1983  In  presenting  requirements  this thesis  f o r an a d v a n c e d  of  British  it  freely available  agree for  that  Columbia,  I agree  that  the L i b r a r y  shall  and s t u d y .  I  f o r extensive  p u r p o s e s may  f u l f i l m e n t of the  degree a t the U n i v e r s i t y  f o r reference  permission  scholarly  in partial  for  that  copying  f i n a n c i a l gain  Department o f  Date  DE-6  (2/79}  of this  It is thesis  n o t be a l l o w e d w i t h o u t my  permission.  The U n i v e r s i t y o f B r i t i s h 2075 Wesbrook P l a c e V a n c o u v e r , Canada V6T 1W5  thesis  be g r a n t e d by t h e h e a d o f my  or publication  shall  further  copying of t h i s  d e p a r t m e n t o r by h i s o r h e r r e p r e s e n t a t i v e s . understood  make  Columbia  written  ABSTRACT  An analytical  procedure to determine the. 2.lh<LcZL\)Q.neJ>& oh greenhouse,  as 6 0lan. collectors the ciicct  was presented.  oh 6e.ve.KaZ COM traction  to greenhouses.  The orientation  most e-hhe.ctive- construction input to greenhouses.  was developed.  parameters, on solar  radiation  parameter controlling  solar  radiation canopy was also  hector.  greenhouse design, The results  input  oh the. greenhouse was hound to be. the.  The ehhe.cti.ve. albedo oh the plant  hound to be a i>ignihicant  A new solar  This procedure was used to ptie.cU.ct  suitable  hor high latitude  showed that an internal  could be incon.pon.ated at, an integral  solar  legion*  collector  part oh the greenhouse  design.  The concept developed could be used as a h^ee-standing greenhouse on. in a combination with livestock  The ehhiciency conventional  oh the solar  input was investigated  and the shed greenhouses,  a greenhouse-animal shelter The results  building.  indicated  dependent on location)  hor the  both at> a hn.ee-standing unit and  system, using computed simulation  analyses.  that the ehh-tcA-zncy oh solan, input <U> highly the ehh^-^ oh location  on the shed type design  •Id more pro hound.  A typical investigated  case oh a gneenhouse-hog barn production system was using computer simulation  analyses.  that such a hood production system achieves in conventional recovery  The results  a sianihicant  showed  reduction  h^el consumption due to both animal waste heat  and solar  energy  utilization.  ABSTRACT  i  TABLE OF CONTENTS  i i  L I S T OF TABLES  xi  L I S T OF FIGURES  xvi  ACKNOWLEDGEMENTS  XX i  INTRODUCTION  •  1  GREENHOUSE INDUSTRY IN CANADA  2  NEED FOR ENERGY  3  CONSERVATION  PROPOSITIONS  6  OBJECTIVES OF THE STUDY  7  ASSUMPTIONS  ;  8  INFERENCES  8  SCOPE OF THE STUDY  9  ORGANISATION OF THE MANUSCRIPT  10  LITERATURE REVIEW  11  GREENHOUSE THERMAL  ENVIRONMENT MODELS  12  SOLAR HEATING OF GREENHOUSES Non-Integral Solar Excess  Internal  Integral  Solar  19  Collectors  20  Heat C o l l e c t i o n  26  Collectors  GASES OF TOTAL CONFINEMENT  ANIMAL HOUSING  31 UNITS  ....  36  Ammonia  36  Hydrogen S u l f i d e  37  Methane  38  Carbon D i o x i d e  38 ii  CARBON DIOXIDE ENRICHMENT  OF GREENHOUSES  39  GREENHOUSE-LIVESTOCK BUILDING COMBINATION PART I ;  41  ANALYSIS OF THE EFFECT OF SEVERAL CONSTRUCTION PARAMETERS ON THE SOLAR RADIATION INPUT INTO GREENHOUSES  CHAPTER 1. SOLAR RADIATION TRANSMISSION OF GREENHOUSES  44  FACTORS 45  INTRODUCTION  46  SECTION A. ESTIMATION OF THE MONTHLY AVERAGE DAILY BEAM, DIFFUSE AND TOTAL TRANSMITTANCE OF THE GREENHOUSE TRANSPARENT SURFACES  47  Assumptions  48  Theory Formulation  49  SECTION B. ESTIMATION OF THE MONTHLY AVERAGE DAILY BEAM, DIFFUSE AND TOTAL TRANSMISSION FACTORS OF GREENHOUSE Definitions  of Transmission  Beam T r a n s m i s s i o n Diffuse Total  Factors  Factor Factor  D e s c r i p t i o n o f t h e Computer for Transmission Factors Sample O u t p u t :  54  (BTF)  Transmission Factor  Transmission  53  54  (DTF)  55  (TTF)  55  Model 56  R e s u l t s and D i s c u s s i o n ...  SECTION C. USE OF THE TOTAL TRANSMISSION FACTOR TO COMPARE GREENHOUSES FOR THEIR SOLAR- RADIATION INPUT E F F I C I E N C Y  57  66  E f f e c t o f O r i e n t a t i o n on t h e Greenhouse TTF  67  E f f e c t o f D o u b l e G l a z i n g on t h e G r e e n h o u s e TTF  67  E f f e c t of I n s u l a t i n g the North Wall on t h e T T F o f an E a s t - W e s t G l a s s h o u s e  ....  69  E f f e c t of I n s u l a t i n g the North Wall and N o r t h Roof on t h e TTF o f an East-West Glasshouse  72  Effect  72  o f L o c a t i o n on t h e G r e e n h o u s e T T F . .  Shed v s G a b l e G r e e n h o u s e  75  Shed v s B r a c e G r e e n h o u s e  75  Effect  77  o f L o c a t i o n o n Shed G r e e n h o u s e T T F .  E f f e c t o f L e n g t h , W i d t h and I n s u l a t i n g t h e E a s t and West W a l l s on t h e T T F o f a Shed G r e e n h o u s e Conclusions  80 ••  NOMENCLATURE CHAPTER  8  ^ 89  2. TOTAL SOLAR RADIATION CAPTURE FACTORS OF GREENHOUSES  91  INTRODUCTION  92  SECTION A. TOTAL CAPTURE FACTORS FOR GABLE GREENHOUSES  93  Assumptions  94  Theory F o r m u l a t i o n  95  R e s u l t s and D i s c u s s i o n SECTION B. CALCULATION OF CONFIGURATION FACTORS FOR DIFFUSE RADIATION IN GREENHOUSES.  97 101  Assumptions  102  Theory  10 2  Results  and D i s c u s s i o n  103  Effect  o f Greenhouse Width  105  Effect  o f Greenhouse Length  105  Effect  o f Roof S l o p e  109  Conclusions NOMENCLATURE  I l l 113  PART I I ;  ANALYSIS OF GREENHOUSE-LIVESTOCK COMBINATION FOR POSSIBLE ENERGY CONSERVATION  CHAPTER 3. COMPUTER  114  SIMULATION MODEL OF ENERGY  REQUIREMENTS FOR LIVESTOCK BUILDING  115  INTRODUCTION  116  SECTION A. MATHEMATICAL MODEL DEVELOPMENT FOR THE LIVESTOCK BUILDING Assumptions  118 119  H e a t B a l a n c e A b o u t The L i v e s t o c k Building  .  119  T r a n s m i s s i o n Heat T r a n s f e r  120  Ventilation  Heat T r a n s f e r  123  Ventilation Ventilation Control  System C o n t r o l Rate f o r H u m i d i t y  124  Ventilation  Rate f o r Temperature  125  Control  127  Ventilation  Rate  f o r Animal Comfort  H e a t and M o i s t u r e P r o d u c t i o n by L i v e s t o c k E n e r g y C o n s u m p t i o n by V a r i a b l e Speed F a n s SECTION B. COMPARISON BETWEEN SOL-AIR AND HEAT BALANCE METHODS FOR TRANSMISSION LOSS CALCULATION Sol-Air  T e m p e r a t u r e Methods  H e a t B a l a n c e Method Comparison o f t h e R e s u l t s T h r e e Methods  Results  Conclusions NOMENCLATURE  130  131 132  by t h e  and A s s u m p t i o n s  and D i s c u s s i o n  128  135  SECTION C..vGASE STUDY I : HEATING AND VENTILATION REQUIREMENTS OF A CONVENTIONAL SWINE FINISHING BARN Description  128  136  142 143 146 154 155  CHAPTER 4. COMPUTER SIMULATION MODEL OF HEATING REQUIREMENTS FOR A CONVENTIONAL GABLE GREENHOUSE  159  INTRODUCTION  160  SECTION A. MATHEMATICAL MODEL DEVELOPMENT FOR THE GABLE GREENHOUSE  161  Assumptions  162  Heat B a l a n c e About  The G r e e n h o u s e  165  T r a n s m i s s i o n Heat T r a n s f e r  165  Infiltration  166  Heat L o s s  S o l a r E n e r g y C a p t u r e d by t h e Greenhouse SECTION B. CASE STUDY I I : HEATING REQUIREMENTS OF A CONVENTIONAL GABLE GLASSHOUSE Description Results  and A s s u m p t i o n s  and D i s c u s s i o n  167  171 172 173  Conclusions  192  NOMENCLATURE  194  CHAPTER 5. COMPUTER SIMULATION MODEL OF ENERGY REQUIREMENTS FOR A COMBINED GREENHOUSELIVESTOCK BUILDING  198  INTRODUCTION  199  SECTION A. MATHEMATICAL MODEL DEVELOPMENT FOR THE GREENHOUSE-LIVESTOCK COMBINATION  200  Assumptions  201  Heat B a l a n c e About Zone I :  Attic  Zone I I : Zone I I I :  The B u i l d i n g Space  Livestock  202 202  Building  Greenhouse  A d v a n t a g e s and D i s a d v a n t a g e s o f D i r e c t Use o f E x h a u s t A i r  202 203 205  SECTION B. CASE STUDY I I I : ENERGY REQUIREMENTS OF A GABLE GLASSHOUSESWINE FINISHING BARN COMBINATION Description Results  and A s s u m p t i o n s  and D i s c u s s i o n  225  NOMENCLATURE  227  ANALYSIS OF A SOLAR-SHED LIVESTOCK COMBINATION  CHAPTER 6. COMPUTER  210 212  Conclusions  PART I I I :  209  GREENHOUSE228  SIMULATION MODEL OF HEATING  REQUIREMENTS OF SOLAR-SHED GREENHOUSE  229  INTRODUCTION  230  SECTION A. HEAT BALANCE ABOUT THE SOLAR-SHED GREENHOUSE  231  Assumptions  232  Energy Balance  232  Thermal R a d i a t i o n Heat Loss from Greenhouse Cover C o n v e c t i o n Heat Loss from t h e Greenhouse Cover  236  C a l c u l a t i o n of the Outside Surface T e m p e r a t u r e o f t h e Roof and t h e W a l l s o f t h e Greenhouse  236  C o n d u c t i o n Heat L o s s from t h e Greenhouse  240  Infiltration Greenhouse  240  2 34  Heat L o s s from t h e  Supplemental Heat Requirement SECTION B. CALCULATION OF SOLAR RADIATION CAPTURE BY A SHED-GREENHOUSE AND SOLAR RADIATION INCIDENT ON THE COLLECTOR  240  24 2  Assumptions  243  Estimation of the T o t a l Solar R a d i a t i o n I n c i d e n t on t h e F l a t Plate Solar C o l l e c t o r inside a Shed-Type G r e e n h o u s e  24 3  E s t i m a t i o n o f the T o t a l Solar R a d i a t i o n C a p t u r e d by t h e P l a n t Canopy  247  E f f i c i e n c y o f Solar Capture by t h e G r e e n h o u s e P l a n t Canopy  249  U s e f u l Energy Gain o f the Solar Collector  250  Calculation of Diffuse Configuration Factors  253  Radiation  SECTION C. CASE STUDY I V : SUPPLEMENTAL HEATING REQUIREMENTS OF A SOLAR-SHED GREENHOUSE Description Results  and A s s u m p t i o n s  and D i s c u s s i o n  259 260 261  E f f e c t o f S e l e c t i v e C o a t i n g and Average Temperature o f t h e Absorber Plate  273  Conclusions  276  NOMENCLATURE  279  CHAPTER 7. COMPUTER SIMULATION MODEL OF HEATING REQUIREMENTS OF SOLAR-SHED GREENHOUSE LIVESTOCK COMBINATION  2 87  INTRODUCTION  2 88  SECTION A. DESCRIPTION OF THE COMPUTER MODEL FOR THE SOLAR-SHED GREENHOUSELIVESTOCK BUILDING COMBINATION  289  Assumptions  290  D e s c r i p t i o n o f t h e Computer M o d e l  290  SECTION B. CASE STUDIES V AND V I : HEATING REQUIREMENTS OF A SOLAR-SHED GREENHOUSE-SWINE FINISHING BARN COMBINATION  29 7  CASE STUDY V  298  Description Results  and A s s u m p t i o n s  and D i s c u s s i o n  Comparison o f R e s u l t s P r e v i o u s Case S t u d i e s  298 298  with 30*8  CASE STUDY V I Description Results  310 and A s s u m p t i o n s  310  and D i s c u s s i o n  313  Conclusions  316  SUMMARY  318  CONCLUSIONS  319  RECOMMENDATIONS  •  320  CONTRIBUTIONS  •  REFERENCES  323  APPENDICES APPENDIX A: APPENDIX B: APPENDIX C:  APPENDIX D:  •  332  CALCULATION OF BEAM TRANSMITTANCE OF GREENHOUSE COVERS  33 3  SAMPLE COMPUTER OUTPUT FOR GREENHOUSE TRANSMISSION FACTORS  33.7  ESTIMATION OF HOURLY DIRECT, DIFFUSE AND TOTAL SOLAR RADIATION ON T I L T E D SURFACES OF ANY ORIENTATION  345  NUMERICAL CALCULATION OF PSYCHROMETRIC PROPERTIES OF MOIST AIR  356  APPENDIX E :  HEAT AND MOISTURE PRODUCTION BY SWINE  APPENDIX F:  SAMPLE COMPUTER SIMULATION OUTPUT FOR A SWINE FINISHING BARN (CASE STUDY I ) .. SAMPLE COMPUTER SIMULATION OUTPUT FOR A CONVENTIONAL GABLE GREENHOUSE (CASE STUDY I I )  APPENDIX G:  APPENDIX H.  APPENDIX I . APPENDIX J :  322  ..  36 2  366 379  SAMPLE COMPUTER SIMULATION OUTPUT FOR A CONVENTIONAL GREENHOUSE-SWINE FINISHING BARN COMBINATION (CASE STUDY I I I )  392  SAMPLE COMPUTER SIMULATION OUTPUT FOR A SOLAR-SHED GREENHOUSE (CASE STUDY I V ) .  405  SAMPLE COMPUTER SIMULATION OUTPUT FOR A SOLAR-SHED GREENHOUSE-HOG BARN COMBINATION (CASE STUDY V)  418  APPENDIX K: APPENDIX L :  APPENDIX  M:  DERIVATION OF EQUATIONS CHAPTER 4  9 & 11 OF  CALCULATION OF THE MEAN PLATE TEMPERATURE OF THE COLLECTOR FOR THE CONSTANT FLOW CASE COMPUTER PROGRAMS  4 31  439 457  LIST  OF TABLES  CHAPTER 1 1.1  1.2 1.3  M o n t h l y a v e r a g e d a i l y t o t a l i n s o l a t i o n on a h o r i z o n t a l s u r f a c e , ground a l b e d o and r a t i o of d i f f u s e to t o t a l r a d i a t i o n f o r the l o c a t i o n s s e l e c t e d f o r t h i s study Sample c o m p u t e r o u t p u t f o r an E-W s i n g l e g l a s s c o v e r g r e e n h o u s e ( V a n c o u v e r ; December) Sample c o m p u t e r o u t p u t g l a s s cover greenhouse  59 ....  f o r an E-W s i n g l e (Vancouver; J u l y )  62  63  CHAPTER 2 2.1  R a d i a t i o n c o n f i g u r a t i o n f a c t o r s between t h e two s l o p e s o f r o o f and f r o m one r o o f s l o p e t o g a b l e ends f o r a g a b l e g r e e n h o u s e h a v i n g a w i d t h o f 10 m e t r e s  110  CHAPTER 3 3.1  V a r i a b l e s used t o c a l c u l a t e h e a t i n g v e n t i l a t i o n r e q u i r e m e n t s o f a c o n v e n t i o n a l swine f i n i s h i n g barn  147  CHAPTER 4 4.1 4.2  4.3  V a r i a b l e s u s e d t o c a l c u l a t e h e a t i n g demands of a c o n v e n t i o n a l gable greenhouse  175  Monthly average h e a t i n g l o a d , s o l a r energy i n p u t , s o l a r c o n t r i b u t i o n and s u p p l e m e n t a l h e a t r e q u i r e m e n t s i n MJ p e r m^ o f g r e e n h o u s e f l o o r a r e a and p e r c e n t o f t h e h e a t i n g l o a d s u p p l i e d by s o l a r f o r t h e c o n v e n t i o n a l g a b l e g r e e n h o u s e o f C a s e S t u d y I I - V a n c o u v e r , B.C. ..  177  Monthly average h e a t i n g l o a d , s o l a r energy i n p u t , s o l a r c o n t r i b u t i o n and s u p p l e m e n t a l h e a t r e q u i r e m e n t s i n MJ p e r n\2 o f g r e e n h o u s e f l o o r a r e a and p e r c e n t o f t h e h e a t i n g l o a d s u p p l i e d by s o l a r f o r t h e c o n v e n t i o n a l g a b l e g r e e n h o u s e o f C a s e S t u d y I I - M o n t r e a l , Quebec  179  ..  4.4  4.5  4.6  4.7  4.8  Monthly average h e a t i n g load, s o l a r energy i n p u t , s o l a r c o n t r i b u t i o n and s u p p l e m e n t a l h e a t r e q u i r e m e n t s i n MJ p e r m2 o f g r e e n h o u s e f l o o r a r e a and p e r c e n t o f t h e h e a t i n g l o a d s u p p l i e d by s o l a r f o r t h e c o n v e n t i o n a l g a b l e g r e e n h o u s e o f C a s e S t u d y I I (Minimum I n s i d e T e m p e r a t u r e = 1 5 ° C ) - H a l i f a x , N.S  180  Monthly average h e a t i n g l o a d , s o l a r energy i n p u t , s o l a r c o n t r i b u t i o n and s u p p l e m e n t a l h e a t r e q u i r e m e n t s i n MJ p e r m2 o f g r e e n h o u s e f l o o r a r e a and p e r c e n t o f t h e h e a t i n g l o a d s u p p l i e d by s o l a r f o r t h e c o n v e n t i o n a l g a b l e g r e e n h o u s e o f Case S t u d y I I (Minimum I n s i d e T e m p e r a t u r e = 1 0 ° C ) - H a l i f a x , N.S  182  Monthly average h e a t i n g load, s o l a r energy i n p u t , s o l a r c o n t r i b u t i o n and s u p p l e m e n t a l h e a t r e q u i r e m e n t s i n MJ p e r m2 o f g r e e n h o u s e f l o o r a r e a and p e r c e n t o f t h e h e a t i n g l o a d s u p p l i e d by s o l a r f o r t h e c o n v e n t i o n a l g a b l e g r e e n h o u s e o f C a s e S t u d y I I (Minimum I n s i d e T e m p e r a t u r e = 20°C) - H a l i f a x , N.S  183  E f f e c t o f minimum i n s i d e g r e e n h o u s e t e m p e r a t u r e on s u p p l e m e n t a l h e a t r e q u i r e m e n t and e x p e c t e d e n e r g y s a v i n g s due t o r e d u c i n g t h e minimum t e m p e r a t u r e f r o m 20°C .  185  E f f e c t o f i n f i l t r a t i o n r a t e on s u p p l e m e n t a l heat requirement f o r a conventional gable g l a s s h o u s e k e p t a t a minimum i n s i d e t e m p e r a t u r e o f 20°C  187  CHAPTER 5 5.1  M o n t h l y aavveerraaggee h e a t l o s s , s o l a r e n e r g y i n p u t and s o l a r e n e r g y u t i l i z e d by t h e g r e e n h o u s e i n MJ .._ per m o f f l o o r a r e a f o r the a t t a c h e d greenhouses w i n e f i n i s h i n g b a r n o f C a s e S t u d y I I I (Minimum G r e e n h o u s e T e m p e r a t u r e = 1 5 ° C ) - H a l i f a x , N.S. ..  214  Monthly average h e a t i n g l o a d , waste h e a t c o n t r i b u t i o n t o the greenhouse h e a t i n g l o a d f r o m t h e l i v e s t o c k b u i l d i n g and s u p p l e m e n t a l h e a t r e q u i r e m e n t i n MJ p e r m o f greenhouse f l o o r area f o r the a t t a c h e d greenhouse-swine f i n i s h i n g b a r n o f C a s e S t u d y I I I (Minimum G r e e n h o u s e T e m p e r a t u r e = 1 5 ° C ) - H a l i f a x , N.S.  215  2  5.2  2  ..  5.3  Monthly average heat l o s s , s o l a r energy i n p u t and s o l a r e n e r g y u t i l i z e d by t h e g r e e n h o u s e i n MJ per m o f f l o o r area f o r the attached greenhouses w i n e f i n i s h i n g b a r n o f C a s e S t u d y I I I (Minimum G r e e n h o u s e T e m p e r a t u r e = 10°C) - H a l i f a x , N.S. ..  218  Monthly average h e a t i n g l o a d , waste heat c o n t r i b u t i o n t o the greenhouse h e a t i n g l o a d f r o m t h e l i v e s t o c k b u i l d i n g and s u p p l e m e n t a l h e a t r e q u i r e m e n t i n MJ p e r m o f greenhouse f l o o r a r e a f o r the a t t a c h e d greenhouse - swine f i n i s h i n g b a r n o f C a s e S t u d y I I I (Minimum G r e e n h o u s e T e m p e r a t u r e = 1 0 ° C ) - H a l i f a x , N.S.  219  2  5.4  2  5.5  5.6  ..  E f f e c t o f l o w e r i n g t h e minimum g r e e n h o u s e t e m p e r a t u r e on e n e r g y s a v i n g s f o r t h e a t t a c h e d greenhouse-swine f i n i s h i n g barn o f Case Study I I I  222  Monthly average supplemental heat requirements f o r a c o n v e n t i o n a l and an a t t a c h e d g r e e n h o u s e (MJ p e r m greenhouse f l o o r area) a l s o expected p e r c e n t s a v i n g s as a f u n c t i o n o f t h e minimum greenhouse temperature  224  2  CHAPTER .6 6.1 6.2  V a r i a b l e s used t o c a l c u l a t e of a s o l a r - s h e d greenhouse  heating  demands 262  Monthly average heat l o s s , s o l a r energy i n p u t , s o l a r c o n t r i b u t i o n and h e a t i n g l o a d i n MJ p e r m o f g r e e n h o u s e f l o o r a r e a and p e r c e n t o f t h e h e a t l o s s s u p p l i e d by s o l a r f o r t h e shed g r e e n h o u s e o f Case S t u d y I V - V a n c o u v e r , B.C 2  6.3  Monthly average heat l o s s , s o l a r energy i n p u t , s o l a r c o n t r i b u t i o n a n d h e a t i n g l o a d i n MJ p e r m of greenhouse f l o o r a r e a and p e r c e n t o f t h e h e a t l o s s s u p p l i e d by s o l a r f o r t h e s h e d g r e e n h o u s e o f C a s e S t u d y IV - M o n t r e a l , P.Q  2  63  2  6.4  Monthly average heat l o s s , s o l a r energy i n p u t , s o l a r c o n t r i b u t i o n and h e a t i n g l o a d i n MJ p e r m 2 o f g r e e n h o u s e f l o o r a r e a and p e r c e n t o f t h e h e a t l o s s s u p p l i e d by s o l a r f o r t h e s h e d g r e e n h o u s e o f Case S t u d y I V - H a l i f a x , N.S  2  66  6.5  6.6  6.7  M o n t h l y a v e r a g e h e a t i n g l o a d and s o l a r e n e r g y s u p p l i e d by t h e i n t e g r a l c o l l e c t o r i n MJ p e r m2 o f f l o o r a r e a as w e l l as t h e s o l a r f r a c t i o n s f o r t h e s o l a r - s h e d g r e e n h o u s e o f Case S t u d y I V ..  270  Monthly average supplemental heat requirements f o r t h e c o n v e n t i o n a l g a b l e and t h e s o l a r - s h e d g r e e n h o u s e s i n MJ p e r m2 o f g r e e n h o u s e f l o o r a r e a and p e r c e n t a g e e n e r g y s a v i n g s as a f f e c t e d by l o c a t i o n  272  M o n t h l y and y e a r l y f r a c t i o n o f h e a t i n g l o a d s u p p l i e d by t h e i n t e g r a l s o l a r c o l l e c t o r a s a f u n c t i o n o f the average absorber p l a t e t e m p e r a t u r e and i t s o p t i c a l p r o p e r t i e s f o r t h e s o l a r - s h e d g r e e n h o u s e o f Case S t u d y I V  275  CHAPTER 7 7.1 7.2  7.3 7.4 7.5  7.6  7.7  V a r i a b l e s used t o c a l c u l a t e of a s o l a r - s h e d greenhouse  heating  demands  V a r i a b l e s used t o c a l c u l a t e requirements of a two-level f i n i s h i n g barn  ventilation s h e d swine  300  301  Summary o f r e s u l t s o f t h e s o l a r - s h e d g r e e n h o u s e hog b a r n c o m b i n a t i o n l o c a t e d i n H a l i f a x  303  Summary o f r e s u l t s o f t h e s o l a r - s h e d g r e e n h o u s e hog b a r n c o m b i n a t i o n l o c a t e d i n V a n c o u v e r  305  Comparison o f monthly supplemental heat r e q u i r e m e n t and e n e r g y s a v i n g s by t h e d i f f e r e n t greenhouse s t u d i e d - H a l i f a x  309  Comparison o f monthly supplemental heat r e q u i r e m e n t and e n e r g y s a v i n g s by t h e d i f f e r e n t greenhouse s t u d i e d - Vancouver  310  E f f e c t o f g r e e n h o u s e s i z e on t h e p e r f o r m a n c e o f a s o l a r - s h e d greenhouse-hog barn combination located i n H a l i f a x  314  APPENDIX L.l  L.2  L  E f f e c t of a i r flow r a t e through the c o l l e c t o r on t h e a b s o r b e r and t h e o u t l e t temperature f o r: tthhee ssoollaarr--sshheedd ggrreeeennhhoouussee ooff ccaassee ssttuuddyy IV ( V a n c o u v e r , B.C.)  450  E f f e c t of a i r flow r a t e through the c o l l e c t o r on t h e s o l a r e n e r g y c o l l e c t e d and s o l a r f r a c t i o n f o r the s o l a r - s h e d greenhouse of case s t u d y IV ( V a n c o u v e r , B.C.)  452  CHAPTER 1 1.1  1.2  1.3  1.4  1.5 1.6  1.7 1.8 1.9 1.10  1.11  1.12  M o n t h l y a v e r a g e d a i l y beam t r a n s m i t t a n c e f o r v a r i o u s s u r f a c e s o f a greenhouse w i t h single glass cover  60  Montly average d a i l y t o t a l transmittance f o r v a r i o u s s u r f a c e s o f a greenhouse w i t h single glass cover  61  M o n t h l y a v e r a g e d a i l y beam, d i f f u s e and t o t a l solar transmission factors f o r a gable greenhouse  64  E f f e c t o f E-W and N-S o r i e n t a t i o n on t h e t o t a l transmission factor f o r a gable greenhouse  68  E f f e c t o f d o u b l e g l a z i n g o f an E-W o r i e n t e d g l a s s h o u s e on t h e t o t a l t r a n s m i s s i o n f a c t o r  70  E f f e c t of i n s u l a t i n g the north wall or north w a l l and r o o f o f an E-W o r i e n t e d g l a s s h o u s e on t h e t o t a l t r a n s m i s s i o n f a c t o r  71  E f f e c t o f l o c a t i o n o f an E-W o r i e n t e d g l a s s h o u s e on t h e t o t a l t r a n s m i s s i o n f a c t o r  73  Comparison f o r gable,  of the t o t a l transmission factors B r a c e and s h e d - t y p e g r e e n h o u s e s  76  E f f e c t o f l o c a t i o n on t h e t o t a l t r a n s m i s s i o n f a c t o r f o r a shed-type greenhouse  78  C o n t r i b u t i o n by t h e d i f f e r e n t s u r f a c e s o f a s h e d - t y p e g r e e n h o u s e f o r t h e beam, d i f f u s e and t o t a l s o l a r r a d i a t i o n by month  81  E f f e c t o f l e n g t h and i n s u l a t i n g t h e e a s t and w e s t w a l l s o f a s h e d - t y p e g r e e n h o u s e on i t s total transmission factor  83  C o n t r i b u t i o n o f t h e e a s t and w e s t w a l l s o f a s h e d - t y p e g r e e n h o u s e t o t h e d i f f u s e and t o t a l s o l a r r a d i a t i o n i n p u t as a f u n c t i o n of greenhouse l e n g t h  84  1.13  E f f e c t o f l e n g t h , w i d t h and i n s u l a t i n g e a s t and w e s t w a l l s o f an E-W s h e d g r e e n h o u s e on i t s monthly average d a i l y t o t a l t r a n s m i s s i o n factor  85  CHAPTER 2 2.1  2.2 2.3  2.4  2.5  E f f e c t o f p l a n t a l b e d o on t h e s o l a r r a d i a t i o n capture f a c t o r f o r a gable greenhouse  98  R a d i a t i o n c o n f i g u r a t i o n f a c t o r between two r e c t a n g l e s f o r m i n g an a r b i t r a r y a n g l e  104  E f f e c t o f l e n g t h and w i d t h on t h e r a d i a t i o n c o n f i g u r a t i o n f a c t o r s f o r gable greenhouses h a v i n g a r o o f s l o p e o f 15 d e g r e e s  106  E f f e c t o f l e n g t h and w i d t h on t h e r a d i a t i o n c o n f i g u r a t i o n f a c t o r s f o r gable greenhouses h a v i n g a r o o f s l o p e o f 20 d e g r e e s  107  E f f e c t o f l e n g t h and w i d t h on t h e r a d i a t i o n c o n f i g u r a t i o n f a c t o r s f o r gable greenhouses h a v i n g a r o o f s l o p e o f 25 d e g r e e s  108  CHAPTER 3 3.1 3.2  3.3  T h e r m a l r a d i a t i o n e x c h a n g e between a and i t s e n v i r o n m e n t  134  H o u r l y t e m p e r a t u r e and s o l a r r a d i a t i o n on a h o r i z o n t a l s u r f a c e used f o r the c a l c u l a t i o n o f t r a n s m i s s i o n h e a t l o s s by t h e s o l - a i r t e m p e r a t u r e a n d h e a t b a l a n c e methods  137  Comparison o f h o u r l y t r a n s m i s s i o n heat l o s s as e s t i m a t e d u s i n g s o l - a i r t e m p e r a t u r e equations (Threlkeld, O'Callaghan) and c a l c u l a t e d by h e a t b a l a n c e a b o u t t h e w a l l s of a t y p i c a l farm b u i l d i n g ( a = 0.2; e = 0.9)  140  Comparison o f h o u r l y t r a n s m i s s i o n heat l o s s as e s t i m a t e d u s i n g s o l - a i r t e m p e r a t u r e e q u a t i o n s ( T h r e l k e l d , O ' C a l l a g h a n ) and c a l c u l a t e d by h e a t b a l a n c e a b o u t t h e w a l l s of a t y p i c a l farm b u i l d i n g ( a = 0.2; = 0.2)  141  g  3.4  wall  g  £  3.5  3.6  3.7  3.8  3.9  F l o o r p l a n o f t h e swine u s e d i n Case S t u d y I  f i n i s h i n g barn  C r o s s - s e c t i o n o f t h e swine u s e d i n Case S t u d y I  144 f i n i s h i n g barn 145  V e n t i l a t i o n r a t e r e q u i r e m e n t o f t h e swine f i n i s h i n g b a r n f o r a minimum i n s i d e t e m p e r a t u r e o f 20°C and a maximum i n s i d e r e l a t i v e h u m i d i t y o f 85% f o r t h e o u t s i d e d r y - b u l b and d e w - p o i n t t e m p e r a t u r e s i n d i c a t e d i n t h e graph (January)  149  V e n t i l a t i o n r a t e r e q u i r e m e n t o f t h e swine f i n i s h i n g b a r n f o r a minimum i n s i d e t e m p e r a t u r e o f 20°C and a maximum i n s i d e r e l a t i v e h u m i d i t y o f 85% f o r t h e o u t s i d e d r y - b u l b and dew-point temperatures i n d i c a t e d i n t h e g r a p h (August)  150  Nomograph f o r d e t e r m i n i n g t h e c o s t o f e n e r g y u s e d f o r v e n t i l a t i o n o f swine f i n i s h i n g b a r n s  ...  152  CHAPTER 4 4.1 4.2  4.3  Cross-section of the conventional gable g r e e n h o u s e u s e d i n Case S t u d y I I Monthly average s o l a r energy u t i l i z a t i o n f a c t o r and f r a c t i o n o f h e a t i n g l o a d supplied by p a s s i v e s o l a r f o r an E-W g a b l e g r e e n h o u s e E f f e c t o f l o c a t i o n on t h e s o l a r e n e r g y u t i l i z a t i o n f a c t o r by month f o r an E-W g a b l e greenhouse  174  ....  189  191  CHAPTER 5 5.1  C r o s s - s e c t i o n a l view o f t h e g a b l e greenhousehog b a r n c o m b i n a t i o n (Case S t u d y I I I )  211  CHAPTER 6 6.1  Schematic o f a s o l a r - s h e d greenhouse showing e n e r g y f l o w s and s o l a r r a d i a t i o n i n c i d e n t on the i n t e g r a l c o l l e c t o r  233  6.2  6.3  6.4  E f f e c t o f l e n g t h and w i d t h on t h e r a d i a t i o n configuration factors f o r solar-shed g r e e n h o u s e s h a v i n g a r o o f s l o p e o f 20 d e g r e e s  ...  256  E f f e c t o f l e n g t h and w i d t h on t h e r a d i a t i o n configuration factors f o r solar-shed g r e e n h o u s e s h a v i n g a r o o f s l o p e o f 30 d e g r e e s  ...  257  E f f e c t o f l e n g t h and w i d t h on t h e r a d i a t i o n configuration factors f o r solar-shed g r e e n h o u s e s h a v i n g a r o o f s l o p e o f 45 d e g r e e s  ...  258  CHAPTER 7 7.1  7.2  7.3  7.4  7.5  7.6 7.7  7.8  Modes o o ff o p e r a t i o n o f tthhee s o l a r h e a t i n g s y s t e m o f a sc ;olar-shed greenhouse-livestock b u i l d i n g combination  293  D i r e c t h e a t i n g o f a s o l a r - s h e d greenhousel i v e s t o c k b u i l d i n g c o m b i n a t i o n by t h e i n t e g r a l s o l a r h e a t i n g s y s t e m (Mode 1 o p e r a t i o n )  29 4  S o l a r e n e r g y c o l l e c t i o n and s t o r a g e i n a solar-shed greenhouse-livestock building c o m b i n a t i o n (Mode 2 o p e r a t i o n )  295  Heating of a solar-shed greenhouse-livestock b u i l d i n g c o m b i n a t i o n from the thermal s t o r a g e (Mode 3 o p e r a t i o n )  296  Schematic o f the c r o s s - s e c t i o n o f a s o l a r - s h e d greenhouse-hog barn c o m b i n a t i o n used i n Case Study V  299  Monthly performance o f the s o l a r - s h e d g r e e n h o u s e - h o g b a r n c o m b i n a t i o n (Case S t u d y  V)  ..  307  Schematic o f the c r o s s - s e c t i o n o f a s o l a r - s h e d greenhouse-hog barn c o m b i n a t i o n used i n Case Study VI  312  E f f e c t o f g r e e n h o u s e f l o o r a r e a on t h e m o n t h l y average f r a c t i o n o f the h e a t i n g l o a d s u p p l i e d by a c t i v e s o l a r c o l l e c t i o n and b a r n w a s t e h e a t r e c o v e r y f o r s o l a r - s h e d greenhouse-hog barn c o m b i n a t i o n o f Case Study VI  315  APPENDIX K K.l K.2  Beam and d i f f u s e s o l a r r a d i a t i o n a v e r t i c a l w a l l o f a greenhouse Diffuse solar radiation of a greenhouse  input  input  from 433  from a g a b l e  roof 436  APPENDIX L L.l  Schematic of a s e c t i o n of the a i r s o l a r l o c a t e d w i t h i n a s o l a r - s h e d greenhouse  collector 441  The  author wishes to express h i s  appreciation for  to Professor  h i s guidance,  throughout the Sincere  solar  gained not  period  of  thanks are  e n e r g y and  this due  heat  the  have been  Soil  Science  constructive  Dr.  Department of  and supervisor,  criticism  study.  t o Dr.  M.  Iqbal  for helping transfer.  me  of  the  Department  understand  Without the  the  science  background  this  study  would  possible. extended  Science, and  thanks  research  from h i s e x c e l l e n t graduate c o u r s e s ,  Thanks are of  Staley,  e n c o u r a g e m e n t and  of Mechanical Engineering of  L.M.  sincere  Dr. J.W.  P.A.  t o Dr.  T.A.  Jolliffe  Zahradnik  and  Black of of  the  Dr.  Department  Department of  N.R.  Bio-Resource Engineering  the  Bulley  for their  of  Plant  the  invaluable  suggestions. The  author expresses h i s  Chong and  Ms.  V.  in  and  editing  typing  Finally, H y d r o and  the  Ellis  for their some p a r t s  financial  Power A u t h o r i t y  Engineering  sincere  appreciation  efficiency of  the  assistance  of  British  D.  co-operation  thesis. Columbia  through the Graduate Research  T e c h n o l o g y Awards p r o g r a m i s  acknowledged.  and  t o Mrs.  gratefully  and  INTRODUCTION  GREENHOUSE  INDUSTRY IN CANADA*  Greenhouse p r o d u c t i o n o f f l o w e r s , n u r s e r y p l a n t s and vegetable  crops  agriculture.  i s a significant  The 19 80 t o t a l  component o f C a n a d i a n  s u r f a c e a r e a u n d e r g l a s s and  p l a s t i c was e s t i m a t e d  a t 382.76  of Ontario accounting  f o r 60 p e r c e n t  British  less  Columbia w i t h  slightly  over  ornamentals,  11 p e r c e n t . bedding  than  hectares, with  o f the t o t a l ,  14 p e r c e n t  The t o t a l  f o l l o w e d by  and Quebec  with  sales value of flowers,  p l a n t s a n d v e g e t a b l e s was e s t i m a t e d a t  over  216 m i l l i o n  used  by t h e g r e e n h o u s e i n d u s t r y was o v e r  o r 11.6 p e r c e n t  the province  dollars  i n 1980; w h i l e  the t o t a l  fuel  25 m i l l i o n  cost  dollars,  of the sales value.  I n 19 80 t h e a n n u a l  fuel  costs per unit  a r e a under  cover  2 ranged  between 5.53 S/m  i n t h e p r o v i n c e o f Quebec t o  2 9.60 $/m  i n Nova S c o t i a .  The n a t i o n a l  average  was  estimated  2 at  6.6 3 $/m  national in  .  Unit fuel  average  a t 7.07 $/m  because o f i t s l a r g e  s u r f a c e area under cover; w h i l e  to r e l a t i v e l y 5.70  i n British  warm c l i m a t e , t h e u n i t  fuel  to the  contribution  C o l u m b i a , due  c o s t was o n l y  $/m . 2  The low f u e l attributed  costs per unit  to the fact  do n o t o p e r a t e *  c o s t i n O n t a r i o was c l o s e s t 2  a r e a i n Quebec may be  t h a t some g r e e n h o u s e s i n t h e p r o v i n c e  f o r the entire  year.  I n Nova S c o t i a ,  the high  A l l the s t a t i s t i c a l information i n this section i s derived by t h e a u t h o r f r o m S t a t i s t i c s C a n a d a , G r e e n h o u s e I n d u s t r y , C a t a l o g u e 22-202, 1979-1980.  fuel  costs per unit  higher  fuel  greenhouse  area  c o u l d be e x p l a i n e d  p r i c e s and c o l d e r c l i m a t e than  by  i n southern  Ontario.  NEED FOR ENERGY CONSERVATION  The  need  f o r energy c o n s e r v a t i o n  of energy u t i l i z a t i o n the fuel  continuous  and r e n e w a b l e  sources  f o r g r e e n h o u s e h e a t i n g was a r e s u l t o f  increase, f o r the l a s t  decade, o f c o n v e n t i o n a l  costs. The  increase  i n energy  c o s t s have f o c u s e d  the a t t e n t i o n  of greenhouse o p e r a t o r s  on c o n s e r v a t i o n methods s u c h as  installation  c u r t a i n s , use o f double  efficient  o f thermal  greenhouse d e s i g n s ,  growing p l a n t s with  applying  fossil  fuel  utilization,  conservation  s u b s t i t u t i o n programs.  author  into  These i n c l u d e d w a s t e  heat  However, much more r e s e a r c h ,  i n adverse  there  i s no s i n g l e  b e l i e v e s a combination solar  solution  t o the energy However, t h e  o f new e n e r g y c o n s e r v i n g  energy u t i l i z a t i o n  may a l l e v i a t e  operators.  development  climatic conditions.  f a c i n g the greenhouse i n d u s t r y today.  concepts, re-use  some g r o w e r s went  p r o j e c t s a r e needed t o k e e p a v i a b l e g r e e n h o u s e  operating  Obviously dilemma  In conjunction  c o m b u s t i o n o f wood and wood r e s i d u e s , and s o l a r  demonstration  industry  techniques,  and more  i n the season, or  r e q u i r i n g lower temperatures.  energy u t i l i z a t i o n . and  planting late  covers  and w a s t e h e a t  the burden o f high  fuel  costs  i d e a s and  r e c o v e r y and f o r greenhouse  The  work p r e s e n t e d  collection use  and  in this  utilization,  and  study  on  animal waste h e a t  f o r g r e e n h o u s e h e a t i n g , i s o n l y one  concepts  which might prove  internal  reasonably  sources.  s h o u l d be  T h e r e f o r e , the  taken  combination  as  with  a partial  o t h e r energy  recovery  efficient  and  i n reducing  non-renewable  f o l l o w i n g proposed  solution  energy  o f t h e many p o s s i b l e  t h e d e p e n d e n c e o f t h e g r e e n h o u s e i n d u s t r y on energy  solar  and  concept  s h o u l d be  applied i n  c o n s e r v a t i o n methods f o r  green-  houses . In t h i s  study,  s t o c k b u i l d i n g s be heat  adjacent  retrofit  new  efficient  The and  used  design  of the  construction oriented  east-west,  two  shed  animal  shelter  permit  the  south-facing  the  and  a  new  investi-  collection  the  f o r ease  The  expected  of  long-axis  a v e r t i c a l w a l l at the  solar  a  ease o f c o n s t r u c t i o n  structure, with  One  to  operations.  Obviously,  proposed.  live-  i n c o r p o r a t i o n of  radiation  o t h e r a greenhouse. of  energy  section  ridge i s an  T h i s d e s i g n would  collector  inside  the  t h e u p p e r p o r t i o n o f t h e d i v i d i n g w a l l on  side.  manner, i s n o t  gable  s e c t i o n s , was and  solar  from  n e e d t o be  d e s i g n were:  internal  d i v i d e d by  installation  g r e e n h o u s e , on  f o r expansions  heat  solar  s t r u c t u r e s and  a t t a c h e d greenhouse.  a standard  giving  situations  f o r t h e new  improvement o f t h e  efficiency  Two  of e x i s t i n g  criteria  t h a t animal  i n conjunction with  greenhouses.  gated: and  i t i s proposed  the  placement of the c o l l e c t o r ,  in  to i n t e r f e r e with  normal  p l a n t s or  this  operations  within  t h e greenhouse.  seen  i f the shed-shaped  well  as a c o n v e n t i o n a l  area,  shape greenhouse  new d e s i g n  was t h e n  19 80,  Agriculture Saanichton formance located by  called  Canada  greenhouse  structure.  could  This  "solar-shed s e p a r a t e l y and  g r e e n h o u s e was c o n s t r u c t e d  R e s e a r c h and P l a n t  on Vancouver  et  study,  There-  a livestock building.  Quarantine  Island, B r i t i s h  compared  a t t h e same s i t e .  Staley  than a gable  the shed-shaped  i n this  floor  i t s performance  by t h e a u t h o r a s a  a solar-shed  i s being  identical  Surprisingly  better  as a f r e e - s t a n d i n g  a n d was a n a l y s e d ,  combination with In  that  t o be  a t l e a s t as  under Vancouver c l i m a t i c c o n d i t i o n s .  efficiently  greenhouse"  indicated that  was s i g n i f i c a n t l y  i t was t h e n d e c i d e d  a l s o be used  in  gable greenhouse having  t h e o r e t i c a l analyses  a solar collector  fore,  greenhouse would p e r f o r m  o r i e n t a t i o n and c o n s t r u c t i o n m a t e r i a l s .  enough, as  However, i t r e m a i n e d  Preliminary  Station i n  Columbia.  to a conventional  a t the  I t s per-  gable  glasshouse  r e s u l t s were  presented  al.(1981). i  It  i s hoped  greenhouse  that  the data  a t S a a n i c h t o n w o u l d be u s e d  m a t h e m a t i c a l model d e v e l o p e d it  possible  locations  c o l l e c t e d from  i n this  i n Canada  and e l s e w h e r e .  experimental  forcalibration  study.  t o p r e d i c t i t s performance  the  This  accurately  would  o f the make  at other  PROPOSITIONS The this 1.  f o l l o w i n g p r o p o s i t i o n s were c o n s i d e r e d  High costs  of energy are  plaguing  greenhouse crops,  even though the  steps  f u e l by  to conserve  double  s p a c e between t h e s e a s o n and  the  producers  growers are  installing  layers of p l a s t i c with  l a y e r s , p l a n t i n g crops  (Baird et  of  taking  n i g h t heat  late  growing p l a n t s which have lower  requirements  saving  an a i r in  the  temperature  al.(1977)).  G r e e n h o u s e s w a s t e s u b s t a n t i a l amounts o f h e a t  by  ventilation  large  amounts o f  during  et Liu  al.(1977), and  day  Brundrett Short  while  they  at night  and  consume (Chandra  T u r k e w i t s c h ( 1 9 79),  et al.(1976),  and Baird  McCormick(19 76),  Carlson(1976) , P r i c e et al.(1976),  (1979), Simpkins e t External  the  supplemental heat  Willits(1980),  3.  to  study:  c u r t a i n s , using  2-  to apply  Willits  et a l .  al.(1979)).  s o l a r c o l l e c t o r s f o r greenhouses r e q u i r e  a  large  amount o f a d d i t i o n a l s p a c e , t h u s r e s u l t i n g i n a w a s t e of valuable 4.  land  (Brundrett  and  Turkewitsch(19 79)).  Internal solar collectors located conventional  greenhouses w i l l  canopy, thus reducing  crop  i n the  r i d g e area  c a s t a shadow on  productivity  the  of plant  (Wiegand(1976)).  5.  Internal  solar  conventional  6.  located  greenhouses w i l l  thus r e d u c i n g collector  collectors  the c o l l e c t i o n  periods,  livestock buildings  t o keep  Spillman et  OBJECTIVES OF THE  levels  aim o f t h i s  (Bon e t a l . ( 1 9 8 1 ) ,  operations  t o reduce the  on f o s s i l  fuels.  objectives:  To d e v e l o p a s i m p l e , m a t h e m a t i c a l model w h i c h the s o l a r  as a f u n c t i o n  radiation  o f measured  waste  would  c a p t u r e o f greenhouses  insolation  and  greenhouse  parameters. ,  To d e v e l o p a c o m p u t e r potential  the  Sokhansanj e t a l . ( 1 9 8 1 ) ,  s t u d y was  f o l l o w i n g were t h e m a i n  construction  during  STUDY  o f greenhouse  predict  solar  al.(1981)).  The p r i n c i p l e  2.  o f the  the humidity w i t h i n  at acceptable  S t a u f f e r and V a u g h a n ( 1 9 8 1 ) ,  1.  efficiency  plants,  and s u p p l e m e n t a l h e a t i s r e q u i r e d , e v e n  c o l d weather  The  s h a d e d by t h e  of  CWiegand (.1976) ) .  Ventilation  dependence  be  on t h e n o r t h w a l l  s i m u l a t i o n model  e n e r g y s a v i n g s due  for estimating  t o the u t i l i z a t i o n  animal h e a t from l i v e s t o c k  buildings  of  t o supplement  g r e e n h o u s e h e a t i n g demand i n a g r e e n h o u s e - a n i m a l  shelter  combination. 3.  To d e v e l o p a s u i t a b l e  system f o r improving i n t e r n a l  s o l a r e n e r g y c a p t u r e by greenhouse-livestock  the greenhouse  building.  i n an  integrated  The m a j o r were as 1.  2 and 3  follows:  Livestock or v i c e  producers are w i l l i n g  versa,  producer 2.  assumptions u n d e r l y i n g o b j e c t i v e s  to operate  o r a c o o p e r a t i v e between a  greenhouses livestock  and a g r e e n h o u s e o p e r a t o r c o u l d be  Exhaust a i r from the l i v e s t o c k b u i l d i n g a detrimental  effect  organized.  does n o t h a v e  on t h e g r o w t h o f g r e e n h o u s e  crops.  INFERENCES The m a j o r  inferences  related  to this  s t u d y were t h e  following: 1.  D a y t i m e w a s t e h e a t f r o m a g r e e n h o u s e c a n be s t o r e d f o r night  2.  A  use.  significant  available 3.  The  to justify  internal affecting An  of  surplus  a n i m a l waste  i t s recovery  i n o r d e r t o accommodate  solar  collection  the a v a i l a b i l i t y  integrated  system.  f o r an  system without of l i g h t  usage.  from the efficient  seriously  to the p l a n t  greenhouse-livestock operation  energy e f f i c i e n t  heat i s  f o r greenhouse  s h a p e o f t h e g r e e n h o u s e c a n be a l t e r e d  conventional  4.  amount  than a separate greenhouse  canopy.  i s more production  The using  scope of t h i s  computer  stages.  simulations.  In the f i r s t  construction  The  limited  parameters  including  radiation  theoretically.  of  shape  a livestock  shed greenhouse. model was the  conservation  the greenhouse  were  In the second s t a g e , m a t h e m a t i c a l subsystems  These  a conventional  In the t h i r d  s t a g e . .The  as p o s s i b l e  such t h a t  greenhouse,  a single  of the  subsystems  greenhouse  included;  and  s t a g e , a computer  computer  livestock  a  solar-  simulation  greenhouse  either  free-standing  building.  The  complete  computer  In the f o u r t h  finishing  b a s e d on e n e r g y  a  program  single  solar-shed to a  was  livestock  written  s t a g e , t h e computer  the f e a s i b i l i t y  house  general  conventional  or attached  b a r n c o m b i n a t i o n , and  greenhouse-swine  a  c o m b i n a t i o n , and  used t o i n v e s t i g a g e  greenhouse-hog  k e p t as  to analyse a  building,  shelter  FORTRAN l a n g u a g e .  model was  i t c o u l d be u s e d  greenhouse-animal  s t u d y was  four  d e v e l o p e d b a s e d upon t h e m a t h e m a t i c a l m o d e l s o f  second  model was  of  greenhouse  c a p t u r e d by  combination.  building,  investigations  and e n e r g y  m o d e l s were d e v e l o p e d f o r t h e d i f f e r e n t greenhouse-livestock  to  study c o n s i s t e d  stage, the e f f e c t  m e a s u r e s on t h e s o l a r studied  s t u d y was  a solar  combination.  savings only.  of a  i n the simulation  conventional  assisted The  feasibility  For the convenience manuscript  and c l a r i t y  i s presented i n three separate parts.  deals with the e f f e c t i v e n e s s where t h e s o l a r  radiation  c a p t u r e by g r e e n h o u s e s respectively.  Part  situation  building  combination.  livestock  while  solar  building  combination  includes  Chapter  is  In t h i s  energy  1 and C h a p t e r  the f e a s i b i l i t y  part,  Chapter  Chapter  2,  of a  utilization  i s treated  i s investigated  i n Part  i s given i n d e t a i l ,  of this  new  subsystem,  i n Chapter  5.  i n a greenhouse-livestock  6 where t h e d e v e l o p m e n t  concept  3 i s devoted t o  4 t o the greenhouse  o f the subsystems  energy  greenhouse  of the three parts  exception of Section diffuse  radiation  needed  Also, in  and t h e n t h e s o l a r  collectors,  III.  This  part  of the solar-shed  and C h a p t e r  7 where t h e  d e s i g n t o an a n i m a l  shelter  investigated. Each  is  Part I  as s o l a r  are c o v e r e d i n Chaper  subsystem,  Finally,  combination  input  this  of a conventional greenhouse-livestock  the combination  greenhouse  o f greenhouses  II investigates  retrofit  the  of presentation,  for full  B of Chapter  configuration  be r e a d s e p a r a t e l y w i t h t h e  2, where t h e c a l c u l a t i o n o f  factors  f o r gable  understanding o f the m a t e r i a l  the mathematical  Chapter  could  model f o r a l i v e s t o c k  3 i s a requirement  f o r Chapter  7.  greenhouses i n Chapter  building  4.  developed  LITERATURE REVIEW  GREENHOUSE THERMAL ENVIRONMENT Most o f t h e e x i s t i n g the energy  mathematical  b a l a n c e method.  fluxes  components;  a n d g r e e n h o u s e a i r mass.  an e n e r g y  greenhouse system. simultaneous  of  t h e components. Several  balance  algebraic  models  cover,  inside  equations  t h e most i m p o r t a n t  section  of  temperature  The d i f f e r e n c e s  to arrive  implicitly, having  treat  the s o i l  development  explicitly or  a l l components o f t h e g r e e n h o u s e heat c a p a c i t y ;  capacity  system as  while others, single out  component a s h a v i n g a s i g n i f i c a n t  heat  capacity.  However, some o f t h e a u t h o r s o f t h e s e m o d e l s have a l s o concern  about  negligible  treating  heat c a p a c i t y ,  Obviously, the  system  the plant  solution.  a s s u m p t i o n , where d i s c r e p a n c i e s  Some o f t h e m o d e l s , e i t h e r  a negligible  between  at a final  between m o d e l s o c c u r , i s t h e t r e a t m e n t o f t h e h e a t the greenhouse.  system  t h e temperatures  underlying their  t h e boundary c o n d i t i o n s chosen Probably  to y i e l d  i s the p r e d i c t i o n  the greenhouse.  thus  component o f t h e  i s the generation of a  these models a r e t h e assumptions  of  plant  The h e a t and mass  are discussed i n this  whose m a j o r o b j e c t i v e humidity  f o r each  The r e s u l t  of  and  of dividing  among t h e s e components a r e m o d e l e d m a t h e m a t i c a l l y  obtaining  and  m o d e l s a r e b a s e d on  T h i s method c o n s i s t s  the greenhouse i n t o d i f f e r e n t canopy, ground  MODELS  expressed  c a n o p y component a s h a v i n g a  b u t none h a s c o n s i d e r e d i t o t h e r w i s e .  the c h o i c e o f the assumptions  with respect to  component's h e a t c a p a c i t y d e p e n d s on t h e i n t e n d e d  use  of the model.  properties of  I f the d e t e r m i n a t i o n o f p s y c h r o m e t r i c  of the a i r w i t h i n  the greenhouse i s the  the model development, t h e n the h e a t c a p a c i t y  and  perhaps  full  t h a t o f the p l a n t  canopy  s t a g e o f growth) s h o u l d be  hand, i f t h e o b j e c t i v e  considered.  Other  that  is  o b t a i n a b l e , w o u l d be into  primary on  s h o u l d be  variables  preferred.  determined  s u r f a c e and  descriptions  to mathematical  house t h e r m a l Walker predicting  of  state  that  by  thermal  boundary  are  F o r example,  easily  t h e use  temperature  the mathematical  ambient a i r  of  Preferably,  as s o l a r  the  net as  these  model  radiation  from  incident  temperature.  f o l l o w o f t h e most r e c e n t and f r e q u e n t l y models f o r the p r e d i c t i o n  of a  green-  environment:  temperatures  mathematically  loss,  the o t h e r  Primary  (1965) p r e s e n t e d an a n a l y t i c a l  greenhouses.  heat  climatic  boundary c o n d i t i o n s such  Brief referred  at  1980).  the greenhouse o r the ground  a horizontal  loss,  (Kindelan,  t o t h e m o d e l i s n o t recommended.  variables  On  then the steady  of the boundary c o n d i t i o n s .  conditions,  inputs  plants  soil  d i s c r e p a n c i e s between t h e e x i s t i n g m o d e l s a r e  selections  radiation  of the  o f t h e model i s t h e p r e d i c t i o n  greenhouse h e a t i n g requirements, a n a l y s e s are adequate  (i.e. tall  objective  w i t h i n both heated  A heat balance involving radiation  and  expressed  heat g a i n , conduction  loss  e v a p o t r a n s p i r a t i o n heat  t o atmosphere, loss,  and  for  ventilated  i n a g r e e n h o u s e was  solar heat  procedure  heat  ventilation  furnace  heat.  Experimental  t e s t s were c o n d u c t e d  applicability  of  the a n a l y t i c a l  of greenhouse temperatures*  to determine  procedure  They f o u n d  between t h e p r e d i c t e d and  observed  for periods of high  radiation  solar  was  required.  The  analytical  for  predicting  the greenhouse heat  weather p e r i o d s but Selcuk equations 24  test  (1970) u s e d  f o r the  a mean  temperature  was  on  requirement  unsteady  s t a t e heat  non-linear d i f f e r e n t i a l  during  cold  and  mass  balance  yielding  equations. finite  These difference  transpiration,  of the heat balance  mass b a l a n c e on  t h e . a i r s t r e a m , heat  canopy and  balance  heat  g r e e n h o u s e . The soil  s u r f a c e , and  condensation  found inlet  on  the cover, heat  balance  over  the  and  plant  s o i l were g i v e n i n d e t a i l , to p r e d i c t  and  outlet  between p r e d i c t e d and  temperatures  of  e t al.(1971)  computer  temperature  measured  presented probably  s i m u l a t i o n model a v a i l a b l e  variations  of the s o i l - p l a n t  plant,  a i r w i t h i n 1.5°C. A a i r humidity  reported.  Takakura detailed  on m o i s t  model was  difference was  and  of  presented.  Formulations  ratios  suitable  A greenhouse a n a l y s i s which i n c l u d e d the e f f e c t s  t h e c o v e r was  percent  ventilation  r e s u l t s were n o t i n c l u d e d .  water e v a p o r a t i o n , p l a n t  cover,  1.4°C  reported  e q u a t i o n s were s o l v e d n u m e r i c a l l y u s i n g t h e  soil  of  i n p u t when  procedure  prediction  difference  f o r c o n t r o l l e d - e n v i r o n m e n t greenhouses  simultaneous  method.  the  t h e most for predicting  canopy-greenhouse  five  system  components.  evaporation, c o v e r , and  The  plant  heat  analysis  transpiration,  used  the temperature  condition.  Beam and  water the  glass  A two-dimensional  t o model the s o i l .  at a certain  diffuse  soil  c o n d e n s a t i o n on  s t o r a g e i n the s o i l .  c o n d u c t i o n e q u a t i o n was requires  included  depth  The  heat  solution  as a b o u n d a r y  components o f s o l a r  radiation  were c o n s i d e r e d s e p a r a t e l y . H e a t b a l a n c e e q u a t i o n s were g i v e n f o r p l a n t soil  surface, The  glass  model was  reasonably  s u r f a c e and tested  a i r within  for specific  greenhouse.  d a y s and  a c c u r a t e v a l u e s f o r temperature  Duncan e t a l .(1976) r e p o r t e d on of  the  surface,  found  variations.  t h e d e v e l o p m e n t and  use  a g r e e n h o u s e s i m u l a t i o n model f o r p r e d i c t i n g w i n t e r h e a t i n g  loads  and  solar  energy  energy  heat  evaluating  radiation  loss,  ground.  the p o t e n t i a l  . accounted  heat  loss,  thermal  r a d i a t i o n 'and  The  solar  as e q u a l t o s o l a r surface multiplied  loss  by  two  The  and  loss, heat  heat  incident  transfer  the a b s o r p t i v i t y  plants  and  ventilation  loss  to  the  losses  a g r e e n h o u s e was  taken  on an o u t s i d e h o r i z o n t a l  c o n s t a n t s , one  of the p l a n t  input,  coefficient  r e p r e s e n t i n g the  t r a n s m i t t a n c e o f the greenhouse c o v e r i n g m a t e r i a l other  excess  greenhouse  conduction heat  heat g a i n w i t h i n radiation  reuse of  radiation  conduction heat  were c o m b i n e d u s i n g t h e o v e r a l l method.  for solar  e v a p o t r a n s p i r a t i o n heat  The  s t o r a g e and  i n a greenhouse w i t h a rock bed.  b a l a n c e model  thermal  of  to give  canopy.  The  o t h e r o b j e c t s i n the greenhouse to  and  the  absorptivity solar  radiation  was  heat  t o the ground  loss  t a k e n as  of greenhouse  t o 0.85.  was  heat  transfer  area of  wall.  Calibration  coefficient  and v a l i d a t i o n  located  mean t e m p e r a t u r e values of l e s s  difference  s i m u l a t i o n were p e r f o r m e d representing  cold  an u n d e r - b e n c h little  but p o t e n t i a l l y  length  equivalent  o f t h e model was within  unit  accomplished  an e x p e r i m e n t a l They  found  between s i m u l a t e d and  a  measured  A n a l y s e s u s i n g the rock f o r two  of  bed  9-day w i n t e r h e a t i n g p e r i o d s  J a n u a r y w e a t h e r and m i l d e r M a r c h w e a t h e r f o r  rock  potential  unit  e q u a l t o t h a t o f one  a t L e x i n g t o n , Kentucky.  t h a n 1°C.  analysis  assumed t o have an  3-day m e a s u r e d d a t a i n A p r i l  greenhouse  Detailed  not g i v e n , but each  p e r i m e t e r was  overall  using  0.70  s t o r a g e system.  f o r excess 11.1%  solar  reduction  Their  energy  results  showed  storage i n January  i n heating requirement i n  March. Froehlich for  predicting  e t al.(1979)  the s t e a d y - p e r i d d i c  greenhouses.  The  plant  floor  canopy,  predicted  temperature  i n closed  surface form.  h u m i d i t y o f the greenhouse found  developed  to p r e d i c t  But  a significant  and  predicted  The  greenhouse a i r ,  c o v e r i n g s u r f a c e s were model a l s o p r e d i c t s  air.  the temperatures  humidity r a t i o s  model  thermal behavior of  of i n t e r n a l  and  difference  a mathematical  Testing  the  o f t h e model  was  with reasonable accuracy.  o c c u r r e d between t h e measured a t low v e n t i l a t i o n  rates.  Kindelan(1980) internal The  d e s c r i b e d a model t o s i m u l a t e  g r e e n h o u s e e n v i r o n m e n t by  s y s t e m was  divided  model p r e s e n t e d internal  by  a i r and  For  the  into  Takakura et a l . ( 1 9 7 1 ) .  heat  flow a n a l y s i s ,  the deep ground temperature obtained  as  balance  f o u r components s i m i l a r  c o v e r were m o d e l e d by  soil  c o n d i t i o n but  the energy  the  was  an  not  The  heat  method.  to  soil,  and  the  plant,  mass  balances.  u n l i k e Takakura's model,  g i v e n as a b o u n d a r y  additional-result  of  the  simulation. It  was  model was  s t a t e d i n the paper t h a t t e s t i n g  carried  a small hydroponic reported. could  o u t by  greenhouse, but  the  be  Froehlich  of  thermal  et al.(1979)  radiation  surfaces.  ambient c o n d i t i o n s i n  accuracy  The  improved by  on  t h e model  e x c h a n g e between p l a n t s and  s u r f a c e s were assumed g r a y ,  diffuse.  represented analysis  greenhouse  isothermal,  and  1  a r e g i v e n , t h e model p r e d i c t s the  model  incorporating a detailed  When t h e g r e e n h o u s e a i r t e m p e r a t u r e  of  of the  evaluated.  Chandra e t al.(1981) by  greenhouse  o n l y p r e d i c t e d v a l u e s were  T h e r e f o r e , the p r e d i c t i o n  not  perfectly  predicting  of the  the heat  and  and  relative  moisture  humidity  balances  greenhouse a i r .  The reported  model was by  t e s t e d u s i n g measured  Froehlich(1976).  The  greenhouse  d a t a were g a t h e r e d  data in a  22 m x 11 m e a s t - w e s t o r i e n t e d located  at Cornell  temperature  University.  the greenhouse,  horizontal  plant and  the model.  Five  test  the t o t a l  days  greenhouse predict  Comparison  floor  hourly  a i r temperature surface  solar  (2 i n A u g u s t ,  radiation  1 i n November  representing  that  temperatures on  a  were u s e d as i n p u t s i n  and  measured  t h e m a t h e m a t i c a l model  thermal environment  and  summer and w i n t e r  o f model p r e d i c t i o n s  data indicated  the greenhouse  and  the greenhouse  2 i n December) were s e l e c t e d conditions.  greenhouse  canopy  surface outside  glasshouse  Hourly data f o r outside a i r  and h u m i d i t y r a t i o ,  and h u m i d i t y r a t i o , in  single-glazed  can  with reasonable  accuracy. Brundrett for  predicting  and A b b o t  hourly or d a i l y  loads of greenhouses. the  following  passive rate,  temperature  i n the o u t s i d e  using  Ontario. are  greenhouses.  or  material, ventilation  the greenhouse  a i r temperature.  The  The  t h e r m a l m o d e l has  been  located  f o u n d t h a t monthly a v e r a g e w e a t h e r  for predicting  annual  fuel  and  model i s a l s o  h e a t i n g l o a d s f o r greenhouses  an e x p e r i m e n t a l g r e e n h o u s e  They  suitable  within  o f the model  covering  air infiltration  stratification  thermal c u r t a i n s .  tested  D u r i n g the development  contribution,  capable of p r e d i c t i n g with  averaged h e a t i n g or v e n t i l a t i n g  f a c t o r s were c o n s i d e r e d ;  solar  variation  (1981) d e v e l o p e d a t h e r m a l m o d e l  equipped extensively  i n southern conditions  consumption  by  During daylight the or  small.  Most o f t h e f o s s i l  a solar With  heating, and is  energy  is  available,  supplemental heat requirement f o r the greenhouse  used a t n i g h t . of  h o u r s when s o l a r  respect solar  to solar  energy  collectors  inside  collection  depending  c a n be  to  c a n be d i v i d e d  greenhouse into  on w h e t h e r  "integral"  the  collector  or i s a separate  the greenhouse.  systems  i s a necessary part  applications  the greenhouse,  construction outside  heating i s  system.  c o l l e c t i o n systems  "non-integral"  solar  f o r greenhouse  Therefore, heat storage  energy c o l l e c t i o n  contained  fuel  i s zero  Furthermore,  classified  as  integral  "active"  or  "passive". A comparison for  greenhouses  of i n t e g r a l  i s given  d i s a d v a n t a g e s by P r i c e collection collector to  system  addition,  externally  heat losses  be e l i m i n a t e d  However, i n t e r n a l  external  collected inherent  will  and g i v e  and  solar  External  and  integral  solar  s a v e on t h e c o s t that  i n external  would  be  collectors  integral  of  needed  an e x i s t i n g  configuration  would  usually  temperatures  greenhouse  for installing  collectors  usually  In  collectors.  c o l l e c t i o n systems  lower o p e r a t i n g  Also,  collectors  heat to the greenhouse.  r e d u c e d by  a poor o r i e n t a t i o n collectors.  An  and on e q u i p m e n t  greenhouse  collectors.  of advantages  e t a l . (1976) .  or at l e a s t  a low e f f i c i e n c y  in a list  i n a greenhouse  construction  transfer  versus non-integral  give  may  have than have  internal higher  collection  efficiency .  orientation  and  of  integral  solar  by  availability  not  tilt  They c a n  for solar  be  installed  energy  collection.  economic  The  size  c o l l e c t o r s w i t h i n the greenhouse i s l i m i t e d  of suitable  space  s i n c e c a r e must be  t o shade p l a n t growing a r e a s w h i l e  collectors  a t optimum  i s usually  the  size  o p t i m i z e d by m a k i n g use  taken  of external  of appropriate  analyses.  NON-INTEGRAL SOLAR COLLECTORS A number o f r e s e a r c h e r s have d e v e l o p e d solar  collectors  plastic  covers  t h i s work was  f o r greenhouse a p p l i c a t i o n s  and  Baird  testing  of t h i s  storage  reservoir  The- c o l l e c t o r s adjustable  a black p l a s t i c  done a t R u t g e r s  M e a r s and  University,  of c o l l e c t o r  underneath  were 1.52  m x  out with  polyethylene p l a s t i c  2.44  collectors  were l a i d  pulled  f o r the heated  was  maintained  by  the  frame w i t h  0.79  A clear  plastic  m and  up  mm  over  mm  the  s h e e t was  used  as  m x 5.49  a t a 40°  tilt  sheets  a  m  with All  angle. of  a i r to  At the bottom the  support black  frame t o p r o v i d e a r e t u r n the b l a c k  header p i p e a t the  holes d r i l l e d  heat  slope angles.  Water f l o w o v e r PVC  a water  s e p a r a t e d by  sheet.  water.  a 31.75  and  and  a d j o i n i n g greenhouse.  3.96  for different  a black polyethylene absorber  gutter  Much o f  Jersey.  coupled with  a p l y w o o d b a c k o v e r w h i c h two  p o l y e t h y l e n e was  clear  sheet.  New  b e n c h e s i n an  legs that allowed  f r a m e s had  absorber  using  (1976) d e s c r i b e d t h e d e v e l o p m e n t  type  t e s t s were c a r r i e d The  low-cost, external  on  152.4  cover.  mm  top  sheet of  centers.  Initially black p l a s t i c  the  authors  s h e e t was  the p o s s i b l e e f f i c i e n c y were n o t by  behaving  adding  A  o b t a i n e d by  and  using a i r i n f l a t i o n  one  clear  the  the  second  since  collects  insulation  large they  test  differences  favorably with  temperature that  to separate  difference  amounts o f low s h o u l d be heat  Roberts collector  these  two  transfer  sheet  up  improved was  collector  sheets  Light  and  force  This  also  absorbed  efficiency  t h e w a t e r and Final  any  by  loss heat i t  i m p r o v e m e n t s were  over  and  the  black  t o improve the evenness o f water  c o n d i t i o n s the authors t o 22°C t h e  low  found  the e f f i c i e n c y  heat,  fell  to l a r g e heat  At  design  33°C  to about o n e - t h i r d  These u n i t s but  that for  cost plastic  conventional collectors.  can  t o be w e l l  provide utilized  storage units with  high  units.'  et al.(1976)  similar  the  sheet.  mesh shade c l o t h  quality  coupled  was  t o the back o f the c o l l e c t o r s  of a conventional c o l l e c t o r .  capacity  sheet over  t o the water.  of a polypropylene collector  areas  efficiency  s h e e t d o e s n o t c r e a t e an  i s transferred  temperature  clear  i s i n contact with  Under t h e i r  compared  a second  reduced  to s h e e t i n g a c t i o n of water  i n s u l a t i o n of the c o l l e c t o r .  polyethylene flow.  Water coverage and  the  This  since large  a g a i n s t the b l a c k c o l l e c t o r  sheet  a d d i t i o n of addition  adding  plastic  this  rivulets.  of the c o l l e c t o r  improvement  was  improved  uneven f o r m i n g  to the water supply  further  sheet  t h a t water flow over  as a c o l l e c t o r .  detergent  improved.  found  designed  a plastic  i n many r e s p e c t t o t h e one  film  solar  described  by  M e a r s and  Baird  (.1976) .  t h e p l y w o o d back and tubes  used  A  31.75  centers distributes the  absorber  Detergent sheeting  was  helped  mm  water  sheet  authors  supports  reported these  that efficiency time  top o f the  this  d e s i g n were 5.38  plastic  w o u l d have t o be  dollars  per  square  cost solar  7.32  m  These  high c a p a c i t y heat  initial per  gain benefit  heat  i n s t e a d of  plate,  The  96 km/h  winds pointed  temperatures.  construction costs  square  metre.  The  from  this  1.61  type  c o n s e r v a t i o n measures;  of  front  support,  and  exchangers. improvements t o t h i s  s y s t e m were r e p o r t e d by M e a r s e t a l . ( 1 9 7 7 ) .  the absorber  angle.  These r e s e a r c h e r s a l s o  paper  F u r t h e r m o d i f i c a t i o n s and  f o r the  easily  the greenhouse system should i n c l u d e :  low-cost,  tube  the  absorber  at higher c o l l e c t i o n  To  large storage;  inflated  good  replaced annually at a cost of  low-cost,  l a y e r s were u s e d  flow  collectors  long with tilt  mm  bottom.  Also,  have w i t h s t o o d  dollars  metre.  collector  frame t o  to achieve  collector  damage.  their  101.6  t o u c h i n g the b l a c k  the  decreased  of w r i t i n g  sandwiched  the b l a c k l a y e r .  collectors  out  polyethylene  r e t u r n g u t t e r a t the  sheet  to vary  snow s t o r m s w i t h o u t  low  the  m h i g h and  and  for  sheet  t o p r o d u c e an e v e n f l o w o f w a t e r .  adjustable  the  from  a c t i o n of water over  were c o n s t r u c t e d 3.05  clear  h e a d e r p i p e w i t h h o l e s on  to the  top  done away w i t h  air-inflated,  added t o t h e w a t e r s u p p l y  p r e s s u r e o f the c l e a r  At  two  has  with a black polyethylene absorber  between them.  over  This collector  Four  plastic  five.  The  collectors  layers  and  a b l a c k tube  and  back i n s u l a t i o n .  collector  had  a  clear,  to a c t Also, i t  as  was  found  absorber  t h a t an a l u m i n i z e d plate  layer  and back i n f l a t e d  by 10 p e r c e n t  The  caution that i n direct  flowing  the black p l a s t i c  enough t o p e r m a n e n t l y collector  efficiency  best e f f i c i e n c y fell  Allentown,  site  sheet  to the front  ranged  the heat  loss  insulation.  s u n l i g h t w i t h no w a t e r  collector  c a n become warm sheet.  The  b e t w e e n 40 and 60 p e r c e n t  with  on warm d a y s .  t o 35 p e r c e n t .  a commercial  due t o r e f l e c t i v e  stick  between t h e  cushion reduced  coefficient authors  inserted  clear  On t h e c o l d e s t d a y s  This collector  efficiency  s y s t e m was c o n s t r u c t e d on  i n 1978 a t t h e Kube Pak C o r p o r a t i o n ,  New J e r s e y .  M e a r s e t a l .(1978) r e p o r t e d on t h e c o n s t r u c t i o n o f a 0.54 h e c t a r e vinyl of  curtain  greenhouse w i t h heat  the Rutgers'  solar  thermal  exchanger coupled  storage  t o 1000 s q u a r e  Further information concerning the  performance o f the Rutgers  system f o r o t h e r  of  c a n be f o u n d  greenhouse a p p l i c a t i o n s  Mears e t a l . ( 1 9 7 9 )  and Simpkins  a low-cost,  air-heating  solar  glazing  was  and t h e c o s t was o n e - h a l f  of  solar  28 gauge s h e e t  State  steel  a  flat  Construction  to one-third that of a  The a b s o r b e r  painted f l a t  University  c o l l e c t o r with  f o r greenhouse a p p l i c a t i o n s .  collector.  heating  e t a l . (1979).  fiberglass  conventional  solar  i n p u b l i c a t i o n s by  M i l b u r n e t a l . (1977) a t P e n n s y l v a n i a  simple  metres  design, non-integral, i n f l a t e d - p l a s t i c - f i l m  collectors.  designed  and v e r t i c a l  black.  p l a t e was made The f r a m i n g  wood and t h e s i d e s and b a c k were i n s u l a t e d w i t h  foil  was  faced  polyurethane board. The  system  A r o c k bed s t o r a g e system  forcollecting  g r e e n h o u s e was f u l l y thermostats collecting  and s t o r i n g  was  h e a t , and h e a t i n g t h e  a u t o m a t e d by u s e o f d i f f e r e n t i a l  t o operate  the appropriate fans f o r heating or  mode.  Another  type o f s o l a r  collector  w h i c h may be  under n o n - i n t e g r a l systems i s t h e s o l a r pond. the Ohio and  State University  and t h e O h i o  ponds' f o r greenhouse h e a t i n g . energy  collector  s t o r a g e o f summer h e a t be  classified  Researchers a t  Agricultural  D e v e l o p m e n t C e n t e r have done e x p e r i m e n t s  a solar  used.  The s o l a r  using  Research 'Solar  pond may a c t b o t h a s  and a h e a t s t o r a g e .  Long  term  f o r winter h e a t i n g requirements can  achieved. Short e t al.(1976)  pond;  3 . 6 m deep,  d e s i g n e d an e x p e r i m e n t a l w i d e , and 1 8 . 3 m l o n g .  8.5m  was l i n e d w i t h two 3 0 - m i l o v e r a sand tration  b o t t o m and i n s u l a t e d  side walls.  g r a d i e n t was e s t a b l i s h e d  A salt  concen-  i n t h e pond so t h a t t h e solution  convective  zone.  t o p 1.8 m o f t h e pond h a d a c o n c e n t r a t i o n g r a d i e n t o f 20  percent  salt  t o zero percent s a l t  l a y e r was n o n - c o n v e c t i v e , with  The pond  chlorinated-polyethylene liners  b o t t o m 1.8 m had a 20 p e r c e n t s a l t The  solar  increasing  salt  r a d i a t i o n passes pond l i n e r ; gradient  this  since  a t the surface.  the s p e c i f i c  gravity increases  c o n c e n t r a t i o n i n t h e zone  through heats  the s a l t  This top  f r o m O - 2.8m depth.  w a t e r and h e a t s  the black  t h e 20 p e r c e n t s a l t c o n c e n t r a t i o n  a t t h e bottom o f t h e pond.  The n o n - c o n v e c t i v e  upper  l a y e r i s e s s e n t i a l l y t r a n s p a r e n t t o incoming u l t r a v i o l e t and v i s i b l e  Solai  radiation  and opaque  non-convective against  top layer  conductive  S o l a r ponds brine w i l l  to reradiated  a l s o p r o v i d e s good  of this  t y p e must  as w e l l  mixing  around  t h e pond.  Initial  gradient;  t h e pond  and o b s t r u c t i n c o m i n g  wind causes  the proper  solar  radiation.  by w i n d , r a i n  benefits  To overcome  and d e b r i s and a l s o  of the cover, Husseini e t a l .  (1979) c o n s t r u c t e d a p o l y e t h y l e n e c o v e r o v e r t h e s o l a r d e s i g n e d by S h o r t e t a l . ( 1 9 7 6 ) . reflector pond Their  They a l s o  on t h e n o r t h w a l l w i t h a t i l t  i n an a t t e m p t tests  the plastic  installed  a  radiation  input.  c o v e r was o f q u e s t i o n a b l e  benefit.  The c o v e r and s u p p o r t i n g frame d e c r e a s e d t h e  radiation  t o t h e pond's  found  that  s u r f a c e by a b o u t  t h e maximum b e n e f i t  w i n t e r months.  The a n n u a l  10 p e r c e n t .  of the r e f l e c t o r  energy  pond  a n g l e o f 75° o v e r t h e  to increase the solar  showed t h a t  surface  and o r g a n i c d e b r i s c a n c o l l e c t i n  some o f t h e p r o b l e m s c a u s e d insulating  that  as e x p e c t e d , b u t  r a i n water d i l u t e s  at the surface;  study  effectiveness  o p e r a t i o n showed  t o perform  gradient  to  be l e a k - p r o o f o r t h e h o t  o p e r a t i n g p r o b l e m s were o b s e r v e d : o f the s a l t  insulation  as t h e i n s u l a t i o n  t h e pond h a d a good p o t e n t i a l several  The  losses.  be l o s t ,  of dry s o i l  thermal energy.  They  also  occurred i n the  g a i n o f t h e pond w i t h a  r e f l e c t o r was 12 p e r c e n t f o r a s l o p e o f 7 5 ° , a n d 14 p e r c e n t for  slope equal t o 90°. Shah  pond  e t al.(1981)  concept  added a n o t h e r  refinement to the solar  by u s i n g a h e a t pump t h a t  uses  a s o l a r pond a s  its  heat  source  f o r h e a t i n g t h e greenhouse.  the e f f e c t i v e n e s s  o f t h e h e a t pump as w e l l  A h e a t pump d e s i g n e d in  uses  Also,  s t o r a g e and a v a i l a b i l i t y  increased  t h e ambient  by a h e a t pump.  e x t r a c t e d down t o l o w e r  a i r as i t s h e a t  Energy  temperatures  when t h e s o l a r pond t e m p e r a t u r e  pond.  o f 5°C t o 40°C  and h i g h e r e f f i c i e n c y  a h e a t pump t h a t  is  increases  as t h e s o l a r  f o r a source temperature  t h e pond h a s g r e a t e r s t a b i l i t y  t h e energy  This  than  source.  of stored  energy  c a n be e f f i c i e n t l y i n the heat  i s below t h a t  source  even  o f t h e greenhouse.  EXCESS INTERNAL HEAT COLLECTION An solar  excess  amount o f h e a t  radiation within  noon h o u r s . natural  This  greenhouses  i s usually  and t r a p p e d  available  to collect  this  Many d e s i g n c o n c e p t s excess heat  use (Wilson e t a l . ( 1 9 7 7 ) , B a i r d  and s t o r e  Chandra  energy  collector;  collection  efficiency.  flat  to i t s floor  adopted  analysis, plate  area.  heating load  t o determine  and ways t o i n c r e a s e  i t s solar this  t h e y c o n s i d e r e d t h e greenhouse  solar c o l l e c t o r of surface The g r e e n h o u s e  e f f i c i e n c y was t h e n c a l c u l a t e d of daytime  e t al.(1979)  t h e n o t i o n o f t h e greenhouse  they attempted  efficiency  In t h e i r  as a h o r i z o n t a l equal  i t for  and W i l l i t s ( 1 9 8 0 ) ) .  Wilson e t al.(1977) as a s o l a r  have  e t a l . ( 1 9 7 7 ) , Rotz and  A l d r i c h ( 1 9 7 8 ) , M i l b u r n and A l d r i c h ( 1 9 7 9 ) , A l b r i g h t and  around  e x c e s s h e a t must be e l i m i n a t e d by e i t h e r  or forced v e n t i l a t i o n .  been p r o p o s e d later  from t h e c o l l e c t e d  solar  by d i v i d i n g  by t h e m e a s u r e d  area  collection  the solar  insolation  component  as g i v e n by  weather d a t a . located  They  at C o r n e l l  efficiency,  found  that  University,  the greenhouse s o l a r  as d e f i n e d above, was  Among t h e methods W i l s o n greenhouse s o l a r second  f o r the greenhouse under  cover,  collection  insulation  about  32  were:  of the n o r t h w a l l ,  Baird  insulation the  h e a t i n g system  the greenhouse a t t i c  as  the  bench r o c k  thermal  by  of polypropylene  a layer  storage.  t h a t uses  solar  The  collector  partial  shade c l o t h  shading and  hope t h i s  suitable  f o r ornamental  reduction has  been  Their  in light tested  results  enough h e a t least the  14°C  will  foliage  i n a glasshouse  showed t h a t  Rotz  be  system  acceptable.  located  this solar 1  above ambient.  For  accomplished of  clear  cost of  would  The  h e a t i n g system  the  be percent system  at Bradenton,  reason of l i g h t  Florida.  provides at  availability,  o b v i o u s l y i s not a p p l i c a b l e  under  conditions. and  Aldrich  (197 8)  attempted  computer s i m u l a t i o n s , the p o s s i b l e benefits  is  under-  t o m a i n t a i n a minimum g r e e n h o u s e t e m p e r a t u r e  above d e s c r i b e d s y s t e m  Canadian  an  p r o d u c e r s , where a 50  probably  a  shading  a layer  solar  authors  of  operation of  and  the o n l y a d d i t i o n a l  The  a  greenhouse  partial  p o l y e t h y l e n e which c o n s t i t u t e collector.  f o r t h e use  of thermal  the  input.  e t a l . (1977) d e s c r i b e d t h e d e s i g n and  a greenhouse s o l a r in  radiation  t o improve  a d d i t i o n of  p o r t i o n o r a l l o f t h e n o r t h r o o f , and m o d i f y i n g shape t o m a x i m i z e s o l a r  collection  percent.  e t a l . have p r o p o s e d  efficiency  study,  fuel  to predict, s a v i n g s and  insulation  (double  through cost glazing  and/or thermal (internal  blankets)  and s o l a r h e a t  or external collection)  greenhouse a t e i g h t l o c a t i o n s Their  conclusions indicated  to reduce except  Florida).  less  collection  than  collection  s y s t e m s were a b l e  substantially system.  at a l l locations  T h i s system  regions  (i.e. California,  fuel  the excess  saving. (1979) s t u d i e d t h e e f f e c t i v e n e s s o f  heat  g r e e n h o u s e by c i r c u l a t i n g  generated  by s o l a r  radiation  storage u n i t .  In p a r t i c u l a r ,  a plastic  with  from  inlet  they  storage  system minus t h e p l a s t i c  tubing.  study,  that with  in  internal  Pennsylvania,  could  be met.  found heat  flow r a t e .  units with  t h e warm a i r a  similar  t h i s method o f c o l l e c t i o n cover  The p e r f o r m a n c e o f t h i s  greenhouse, l o c a t e d  crop  heating load  s y s t e m was f o u n d to be zone t e m p e r a t u r e  The u s e o f t h e p e r f o r a t e d c o l l e c t i o n  the r i d g e improved  the c o l l e c t i o n  using  i n t h e i r conclusion to the  i n a single  temperature,  heat  the ridge of the  10 t o 20 p e r c e n t o f t h e a n n u a l  d e p e n d e n t on a m b i e n t air  a system  holes placed along  the r i d g e to the heat  of excess  compared  a rock  a f a n and d u c t i n g t o c i r c u l a t e  the authors  ina  t h e warm a i r a s i t i s c o l l e c t e d  under t h e r o o f r i d g e o f t h e greenhouse through  greenhouse w i t h  solar  i n g r e e n h o u s e s was p r e d i c t e d t o r e s u l t i n  5 percent  tube  only  c l i m a t e r e g i o n s o f t h e U.S., i n t e r n a l  M i l b u r n and A l d r i c h collecting  across the United S t a t e s .  well i n the mild climatic In cold  commercial-sized  that a l l these  requirement  the i n t e r n a l  performed  energy  the f u e l  in a  utilization  efficiency  and  duct i n  o f t h e system.  C h a n d r a and W i l l i t s  (1980) d e v e l o p e d  s i m u l a t i o n model t o p r e d i c t greenhouse a t t a c h e d outside excess  s o l a r energy  predict for  The r o c k  collected  model as p r e s e n t e d temperatures,  storage  storage  situated  i s charged  from  i n the greenhouse.  i n t h e p a p e r was i n t e n d e d t o  relative  h u m i d i t i e s , and h e a t  model was t e s t e d u s i n g m e a s u r e d d a t a  operating  system  predicted  values o f temperatures  close  located i n Raleigh, North  t o the measured d a t a .  system e f f i c i e n c y , experimental  balances  improving  either  e t al.(1979)  Carolina.  However, an e s t i m a t e  predicted or calculated  The reasonably  f o r the from  t e s t e d y e t another  flat  method o f  collector.  wide p o l y e t h y l e n e  This  tubing,  w i t h w a t e r , on t h e b e n c h e s o r g r o u n d between t h e rows  of pots o r p l a n t s . Q-mats*.  are usually Q-mat t u b e s  mass w i t h i n t h e g r e e n h o u s e .  t h e Q-mats i n d i c a t e d incident  These tubes  The p u r p o s e o f t h e s e  thermal  solar  that approximately  r a d i a t i o n was a b s o r b e d  the absence o f p l a n t canopy.  * Trade  a prototype  and h u m i d i t i e s were  t h e greenhouse as a p a s s i v e s o l a r  method c o n s i s t e d o f l a y i n g filled  from  d a t a , was n o t g i v e n .  Albright  with  of a  t h e g r e e n h o u s e a i r and t h e r o c k b e d . The  the  behavior  t o a rock bed thermal  the greenhouse.  The  the thermal  a computer  name.  referred  t o as  i s to increase  T e s t s performed  with  55 p e r c e n t o f t h e  when t h e y were  used  However, when t h e Q-mat  t u b e s were p l a c e d the  bud  the  c a n o p y was  under a t h i c k canopy  stage), only  25  a b s o r b e d by  Experiments with Cornell of  percent  10  percent  Brace I n s t i t u t e  style  greenhouse  d e s i g n was losses  night heating  1975)  t o maximize s o l a r  insulated  north-facing wall solar  interior  face.  inclined  w a l l are  to optimize roof,  and  both  the  the  Brace  experimental  transparent  authors to  40  solar  a  b a s i s f o r the reduce  w a l l are  toward the  of t h i s  transmission  radiation  by  and  are by  the  the and  the  r o o f , and  These angles  of design  east-  south  r e f l e c t i v e m a t e r i a l on  radiation  heat  designs.  transparent,  transparent  new  the chosen  the  south  rear wall  became t o be  known  on  as  greenhouse. Brace  tested during  percent  of  unconventionally  greenhouse  specific.  Institute  surfaces covered  claimed  an  i n p u t and  is inclined  T h i s type  Institute  at  a long-axis oriented  of the  location  reflection  p l a n t canopy.  l e n e was  angle  the  the  An  r o o f and  radiation  The  authors  requirement  The  radiation  g r e e n h o u s e has  south-facing  with  proposed  conventional  west, the  covered  the  indicated a contribution  for colder regions.  proposed  above  greenhouse.  associated with  The  radiation  tubes.  the winter  t o the  Lawand e t a l . ( 1 9 7 3 , shaped  the  solar  Q-mats p e r f o r m e d by  University during  about  of the  (chrysanthemums i n  with  a double  a cold winter  a reduction  greenhouse having layer of  polyethy-  i n Quebec C i t y .  i n heating  requirements  compared t o a c o n v e n t i o n a l , d o u b l e  the  The of  30  layered  plastic  covered  in  yields  crop  greenhouse. increased  light  the  should house.  was a t t r i b u t e d t o  i n the Brace I n s t i t u t e  h a s b e e n done on i n t e g r a l  Integral solar  of collector  collectors  I t i s impossible  to the f l o o r  to i n s t a l l  area  shading  interfering  operations.  Recognizing  heating  normal greenhouse  t h e above l i m i t a t i o n s ,  to apply  o f greenhouses  system o f t h i s  t h e p l a n t s and  researchers  integral- solar collectors  have c o n c e n t r a t e d  rule,  o f the green-  a collector  s i z e w i t h i n the greenhouse without with  t o be  As a g e n e r a l  required f o r solar heating equal  solar  limited  are l i k e l y  small greenhouses.  be a p p r o x i m a t e l y  attempted  green-  period.  research  to relatively  size  production  f o r greenhouses because o f t h e i r  applications.  an i n c r e a s e  COLLECTORS  little  collectors  crop  availability  the winter  INTEGRAL SOLAR Very  They a l s o r e p o r t e d  ( t o m a t o e s and l e t t u c e ) grown i n t h e new The i m p r o v e d  house d u r i n g  limited  greenhouse.  who  t o greenhouse  on t,he u s e o f t h e n o r t h - f a c i n g w a l l  of  the greenhouse.  Previous  s t u d i e s showed t h a t  of  t h e n o r t h w a l l h a d no e f f e c t  on p l a n t y i e l d  insulation  (Willits  et a l .  1979). Light  levels  i n i n s u l a t e d g r e e n h o u s e s s u c h as t h e B r a c e  d e s i g n were i n v e s t i g a t e d by T u r k e w i t s c h for  Toronto  and W i n n i p e g , u s i n g  and B r u n d r e t t ( 1 9 7 9 )  a computer s i m u l a t i o n model.  Four  g r e e n h o u s e s were c h o s e n  an E-W  oriented  latter  i s a m o d i f i e d Brace  Both  the Brace  north  gable, a Brace  and  type  level  When t h e r e s u l t s t h e N-S  the Greensol  have an  E-W  of the  r i d g e was  found less  i n the  two  to c o l l e c t  ridge orientation.  and  reflective  authors  and  the  lowest  greenhouses i n both Liu  and  a flat  60°.  I t w o u l d be  built  inside  The  have proposed  located  on  facing  aluminum s h o u l d be  south  used  area.  a greenhouse at a t i l t  The  dark  c o a t e d , and  t o match t h e v a l l e y s  of a l l  design  angle  radiation  f o r crop  house  authors collector tube  i n the  the top o f the  reflecting  of  a copper  A g u t t e r a t the bottom would  A selective  t o enhance the  the  collection  c o r r u g a t e d aluminum  aluminum c o r r u g a t i o n s , s u s p e n d e d o v e r  water.  that  with  the  t h e r o o f o f an A - f r a m e head  a single-plate,  supply water flow.  of  efficiency  the n o r t h w a l l of the greenhouse.  manifold, with holes d r i l l e d  the heated  radiation  summer c o l l e c t i o n  place collector  recommended t h a t used.  found  i n the  locations.  Carlson(1976)  using  computed.  t h e one  However, when t h e r e s u l t s  efficiency  ing  The  authors.  radiation  i n t h e w i n t e r months t h a n  the h i g h e s t w i n t e r s o l a r  be  the  insulated  more s o l a r  has  to  type.  g a b l e g r e e n h o u s e s were compared,  type  be  by  gable,  f o u r g r e e n h o u s e s were  f o u r g r e e n h o u s e s were c o m p a r e d , t h e  the  oriented  a Greensol  design, developed  radiation  summer months, and  Brace  and  a N-S  wall. Floor  an  f o r study;  collector  collector collect cover  growth i n the  may  plant-  Calculations Maryland  f o rthis  a t 4 0°N l a t i t u d e  design  are presented  for Beltsville,  f o r a g r e e n h o u s e 7.32m l o n g by 6.1m 2  wide. The  The i n t e g r a l  authors  solar  estimated  system c o u l d account  collector  h a s a s u r f a c e a r e a o f 36m .  that the solar f o r 78 p e r c e n t  collector  and s t o r a g e  o f t h e greenhouse  heating  load. 2 A 46.47m  greenhouse w i t h  a flat  a part of the north-facing wall with storage tested  l o c a t e d underneath by C l i c k  one-quarter  pipe  a crushed  the concrete  and P i l e ( 1 9 8 0 ) .  circle  plate solar  c o l l e c t o r as  rock  thermal  f l o o r was d e s i g n e d and  The g r e e n h o u s e was b u i l t  f r a m e members  and  roof.  The  c o v e r i n g was two a i r s e p a r a t e d  t o form  the south  The n o r t h w a l l was an i n s u l a t e d wood  with  wall  frame c o n s t r u c t i o n  layers of polyethylene  sheeting  2 The  28m  flat  f a c i n g w a l l used flat  black,  air-flow  plate  collector  26 guage, c o r r u g a t e d m e t a l  fastened over  channels  behind  t h e w a l l and then  storage.  The  the black metal a i r through  f o r c e d the- h e a t e d  cooled a i r exited  i n s i d e w a l l o f t h e greenhouse. controlled  the c i r c u l a t i n g  When t h e a i r b e h i n d  higher  the rock  through  t h e system.  roofing  collector.  painted  a i r through  the rock  formed  A fan i n  the rock  storage at the front  A differential  the c o l l e c t o r  storage temperature,  that  a plenum a t t h e t o p  thermostat  f a n moving a i r through  collector. than  of the north-  a s y s t e m o f wooden s p a c e r s  the bottom o f t h e w a l l p u l l e d of  on t h e i n t e r i o r  the solar  p l a c e was 1 0 ° C  a i r was  circulated  Data c o l l e c t e d that  a greenhouse  Tennessee,  could  during  of t h i s realize  t h e w i n t e r o f 1979-1980 type, located  significant  i n Cookeville,  energy  l a t e November and b e g i n n i n g a g a i n i n l a t e authors  found t h a t  extend growing The  solar  The  glass  and  as a s o l a r  low  seasons  i n unheated  collectors  collector.  ratios  solar  greenhouse  cover-solar  is  top space  floor  use  area.  system  As  i s empty w i t h a p a r t i a l  The  designed to conduct the flow of c i r c u l a t i n g the c o l l e c t o r  selected  p o r t i o n s of the s o l a r  portion of insolation active  radiation)  the s o l a r formed  fluid  for plant  growth  i s transmitted  so t h a t  to heat i n the c o l l e c t o r  screening  to the crop.  fluid.  have a p p l i c a t i o n  o f some d i r e c t  a  dual sandwich  spaces. bottom  collector  fluid.  only  t h e most  useful  The  portion  trans-  I t appears that  this  i n warm c l i m a t e s where  insolation  fluids  had  in a practical n o t been  application  chosen.  and  of  i s a b s o r b e d and  mid-  i s n e c e s s a r y anyway.  At the time Deminet(1976) p r e s e n t e d h i s paper, the system not t r i e d  layer  (photosynthetically  spectrum at o t h e r wavelengths  technology might  Boeing  The  earlier,  use o f  c a n be c h o s e n t o t r a n s m i t spectrum  the  stated  f o r m i n g two  vacuum.  1976).  glazing  increase  i s basically  layers of glass  approach  (Deminet,  to e f f i c i e n t  f o r greenhouses.  Ideally,  day  an i n t e r e s t i n g  concept would  collector  or  greenhouses.  constraints  collectors  construction with three The  This  until  The  b o t h as t h e g r e e n h o u s e  t o greenhouse  are the major  February.  f o r greenhouse  function  s a v i n g s up  reduce h e a t i n g costs  introduced  collectors  of c o l l e c t o r  integral  system c o u l d  B o e i n g Company h a s  to i n t e g r a l  ratio  this  indicated  suitable  was  collector  R e c e n t l y , van University, roof  B a v e l and  experimented  designed  greenhouse, but Augustine  turf.  behavior filter  It w o u l d be  i n a small,  St.  of these p r e l i m i n a r y  t o some c o n s t r u c t i o n e n g i n e e r i n g a detailed  g a i n e d by that  s t u d y On  c r e a t e d by  the authors  the plumbing  solution,  used  the  from and  as i n f r a r e d solved prior  plant fluidthese  circulation absorbing to  any  application.  i s doubtful that applied  discussions  van  the  fluid-roof  greenhouse  i n c o l d e r r e g i o n s * T h e r e f o r e , no  of t h i s  interested  (1978),  chloride  fluid-  covered with a standard  environment  suggested  & M  c r o p s were grown i n t h e  p r e s e n t p r o b l e m s t h a t must be  practical  The  tests  No  to conduct  Experience  the copper  fluid,  solutions  i n the d i f f e r e n t  roof.  t e s t s were p e r f o r m e d  main o b j e c t i v e s  r a t h e r than  preliminary of  f l o o r was  The  t e s t s were t o f i n d problems,  The  greenhouse.  the  a t Texas A  w i t h what t h e y have c a l l e d  greenhouse concept.  specially  Sadler(1979)  system  reader  B a v e l and  will  be  i s referred  concept further  given during this to publications  D a m a g n e z ( 1 9 7 8 ) , and  van  study.  by v a n  Bavel  Bavel et al.(1980).  Gaseous c o n t a m i n a n t s originate  themselves.  constitute  combination  concept  requires  but a l s o  their  housed  sulfide  contributor  to  c o n c e n t r a t i o n s found  the knowledge n o t o n l y o f a i r from  concentrations.  the  livestock  a i r from  c o n d i t i o n s are not r e a d i l y  However, r e c e n t i n f o r m a t i o n g i v e n by M c Q u i t t y (1982) and  v a n D a l f s e n and  Bulley  animal  available.  and  (1982) c o u l d be  to e s t i m a t e the expected  the  Unfortunately,  c o n c e n t r a t i o n s i n exhaust  under Canadian  guideline  the  from  of the g r e e n h o u s e - l i v e s t o c k b u i l d i n g  a c t u a l d a t a on gas barns  hydrogen  p r e s e n t i n the v e n t i l a t e d  building  also  barns.  Application  gases  M e t a b o l i c p r o c e s s e s by  o f manure i s t h e c h i e f  ammonia, methane and animal  but  buildings  the main s o u r c e o f carbon d i o x i d e i n barns,  while decomposition  in  i n confined animal  n o t o n l y f r o m manure d e c o m p o s i t i o n  the animals animals  found  Feddes used  as a  c o n c e n t r a t i o n s i n the  exhaust a i r . AMMONIA A literature  review undertaken  by  M c Q u i t t y and  Feddes  (1982) r e v e a l e d t h a t NH^  concentrations vary considerably i n  animal barns.  In a w e l l  ventilated  concentrations  appear  V a l u e s o f 50  ppm  b u i l d i n g , -expected  t o l i e i n t h e 5 t o 30 ppm  range.  however, a r e n o t uncommon d u r i n g p e r i o d s  o f w i n t e r minimum v e n t i l a t i o n  rates.  McQuitty  and  in  the  range of  12  ppm  i n two  dairy  Feddes  5 t o 12  broiler  barns.  van  can  be  ppm  During  and  and  less  Bulley  and  concentrations  than  2 ppm  i n four a  range  s u b f l o o r manure  a g i t a t i o n o f manure, h i g h e r  Feddes,  2 to  (.1982) r e p o r t e d  i n four d a i r y units with  a n t i c i p a t e d , p o s s i b l y i n the  (McQuitty  NH^  i n f o u r swine b u i l d i n g s ;  houses;  Dalfsen  between 1 t o 7 ppm storage.  (1982) r e c o r d e d  range o f  NH^  concentrations  100  t o 200  ppm  1982).  HYDROGEN SULFIDE Values  of H S 2  undetectable  t o low  Concentrations buildings Feddes  other  less  four d a i r y barns. mean H S  mean H S than In  while van  less  Dalfsen  than and  10  t o be  ppb  of animals.  i n two  10  70  ppb  Bulley  ppb was  just  under  the  measured  (1982) f o u n d  i n the  conditions.  However, when n.anure i s d i s t u r b e d , an  quantities will in  immediate occur  concentrations.  during  agitation  r e l e a s e of  resulting  was  normal  gas  operating  particularly  i n large  in considerable  They r e p o r t e d  of the  the  found  exhaust a i r .  2  four dairy units during  increase  a concentration of  manure i n t h e  and  slotted-  that H S  i n the  agitation,  winter  authors  above t h e  than i n  and  houses  undetectable  by  buildings.  McQuitty  broiler  f o u r swine b a r n s , of  be  somewhat h i g h e r  concentrations  2  concentrations  2  types  to  confinement animal  i n swine barns tend  housing  of  have b e e n f o u n d  i n many t o t a l  (1982) f o u n d  conditions  floor  concentrations  four d a i r y  2.7  barns.  ppm  METHANE McQuitty  and F e d d e s  concentrations animal  likely  (1982) s t a t e d t h a t  t o be e n c o u n t e r e d  b u i l d i n g s w o u l d n o t be a d i r e c t  even under w i n t e r concentrations  minimum  ventilation  CH  4  i n ventilated health  rates.  hazard, Expected  were n o t r e p o r t e d .  CARBON DIOXIDE C0 in  2  i s normally  the order  present  o f 300 ppm.  Concentrations  t o 3000 ppm were e x p e r i e n c e d During  winter  concentrations buildings,  i n fresh a i r at a concentration i n t h e r a n g e o f 500  i n ventilated  animal  buildings.  c o n d i t i o n s , M c Q u i t t y and F e d d e s ( 1 9 8 2 ) of C0  2  two b r o i l e r  t o be l e s s  than  found  4000 ppm i n f o u r  swine  h o u s e s and f o u r d a i r y b a r n s i n A l b e r t a .  The  o f C O 2 e n r i c h m e n t on g r e e n h o u s e  effect  production  was r e c e n t l y i n v e s t i g a t e d by W i l l i t s  (1981) i n R a l e i g h ,  North C a r o l i n a .  1050  of C 0  2  within  104  Average  concen-  ppm when t h e s e t p o i n t was e s t a b l i s h e d a t 1000 ppm.  14.6 p e r c e n t percent  increase  r e s u l t s i n d i c a t e d an a v e r a g e  f o r t o m a t o e s , 42 p e r c e n t  f o r bedding p l a n t s .  Vetomil Among  were h e a v i e r  i n t h e CO^ e n r i c h e d  i n harvest  increase i n  t e s t e d , pepper  g r e e n h o u s e by 135  tomatoes, then c h e r r y  respectively.  these p l a n t s yields  the bedding p l a n t s  by r e g u l a r  showed i n c r e a s e s percent,  f o r cucumbers and  F o r cucumbers, t h e p e r c e n t a g e  g i v i n g the greatest  production.  followed  increased  r a n g e d between 32.2% t o 60.7% d e p e n d i n g on t h e  c u l t i v a r with  plants  percent,  tomatoes which  w e i g h t s o f 123 p e r c e n t  and 69  No a t t e m p t was made t o "grow o u t "  t o d e t e r m i n e CO,, e n r i c h m e n t e f f e c t  on  fruit  i n the f i e l d .  Obviously, enrichment  the increased  f o u n d by W i l l i t s  t a k e n as a r e p r e s e n t a t i v e the  tested  t h e g r e e n h o u s e r a n g e d between 1000 and  Their experimental of  and P e e t  Greenhouse crops  were t o m a t o e s , cucumbers and b e d d i n g p l a n t s . trations  crop  y i e l d s due t o g r e e n h o u s e C O 2  and P e e t  (1981) c o u l d  c a s e due t o t h e c o m p l e x i t y  i n t e r a c t i o n s between CO,, c o n c e n t r a t i o n s  environmental temperature.  o n l y be  factors including light  of  and o t h e r  i n t e n s i t y and  yield  I n any authors  e v e n t , t h e s t u d y by  showed t h e b e n e f i c i a l  on g r e e n h o u s e in  crop.  increase  greenhouse-animal  effects  building  in yields  shelter  without experimentation.  effect  on g r e e n h o u s e  enrichment  i s not w e l l  defined,  o f c r o p s grown i n a  In a d d i t i o n ,  than C 0 ,  productivity.  n o t be  determined  exhaust a i r from  v a p o u r w h i c h may  crop  2  concentrations  2  combination could  animal barns c o n t a i n s o t h e r gases c o n c e n t r a t i o n s of water  mentioned  of C0  Since the a c t u a l C 0  exhaust a i r from l i v e s t o c k  the p o t e n t i a l  t h e above  2  including  have an  high  adverse  An e x t e n s i v e r e v i e w o f t h e l i t e r a t u r e , for  the present  research project,  revealed  undertaken that  neither  theoretical  concept  o f combined g r e e n h o u s e - l i v e s t o c k b u i l d i n g  was  available.  nor e x p e r i m e n t a l i n f o r m a t i o n on the  However, t h e l i t e r a t u r e  search indicated a  s i g n i f i c a n t amount o f r e s e a r c h , d e v e l o p m e n t and p r o j e c t s were p e r f o r m e d by  mainly  used  i n this  demonstration  on g r e e n h o u s e - r e s i d e n c e  engineers, architects  and e c o l o g i s t s .  case as a s o l a r  systems  combinations  The g r e e n h o u s e i s  c o l l e c t o r p a r t i a l l y .to  p r o v i d e t h e h e a t i n g l o a d o f t h e a t t a c h e d house. In a g r e e n h o u s e - l i v e s t o c k combination, is  totally  different  greenhouse-residence former  combination  heating the  than  combination,  since heat  irrelevant  to this  further.  The i n t e r e s t e d  excellent  papers  Therefore,  combination i s  s t u d y and w i l l  n o t be d i s c u s s e d t o t h e many  published i n the Proceedings  Greenhouse-residence  of the  t o s u p p l y some o f  reader i s referred  c o n f e r e n c e s on S o l a r E n e r g y  * Available  the concept  o f the attached greenhouse.  i n f o r m a t i o n on g r e e n h o u s e - r e s i d e n c e  somewhat  approach  t h a t used w i t h r e s p e c t t o the  i s t o use animal  requirements  the basic  of the annual  f o r H e a t i n g G r e e n h o u s e s and  combinations*.  from N a t i o n a l T e c h n i c a l I n f o r m a t i o n S e r v i c e U.S. D e p a r t m e n t o f Commerce S p r i n g f i e l d , VA 22161  In  1980, r e s e a r c h e r s a t K a n s a s S t a t e  published  a study  combination  dealing with  University  a greenhouse-animal  ( S p i l l m a n e t a l . 1980).  shelter  The m a i n o b j e c t i v e s  of  t h e r e s e a r c h underway a t K a n s a s S t a t e U n i v e r s i t y  to  evaluate y i e l d  with exhaust of  fossil  those with  and q u a l i t y  a i r from  fuel  o f greenhouse crops s u p p l i e d  a hog h o u s e , and t o compare t h e amounts  requirements  o f a c o n v e n t i o n a l greenhouse t o  o f a greenhouse u s i n g exhaust solar The  a i r from  o f an e x p e r i m e n t a l  experimental  w a l l o f a swine f i n i s h i n g  barn  dimensions  o f 6 m by 7.3 m and were c o v e r e d  3  .  B o t h g r e e n h o u s e s have t h e same  polyethylene film.  p e r h o u r o r 1200 m  by a i r i n f l a t e d  The a i r f l o w r a t e f r o m  b a r n was i n t r o d u c e d t o t h e e x p e r i m e n t a l m  unit  and a c o n v e n t i o n a l  for control.  680  facility  greenhouse a t t a c h e d t o the south-  greenhouse  double  animal b u i l d i n g s  storage.  Kansas S t a t e U n i v e r s i t y  consisted facing  energy  were  3  per hour.  t h e hog  greenhouse e i t h e r a t  In a d d i t i o n the  3  experimental storage  g r e e n h o u s e had 7.25 m  f o r excess  internal  solar  S p i l l m a n e t a l (1980) d e a l t of  s u p p l y i n g the greenhouse w i t h  d i o x i d e on c r o p Air a carbon and  samples  vertical heat  rock bed thermal  collection.  exclusively with animal  produced  the e f f e c t s carbon  production. taken w i t h i n the a t t a c h e d greenhouse  d i o x i d e c o n c e n t r a t i o n o f 1500 ppm when b o t h  indicated hoghouse  g r e e n h o u s e were u n v e n t i l a t e d , and 450 ppm t o 600 ppm when  b o t h were v e n t i l a t e d .  In a d d i t i o n  to ventilation  rates,  CO,  concentrations weights  i n t h e g r e e n h o u s e depend upon t h e number  o f the animals  i n the barn;  124 t o 202 hogs a v e r a g i n g  30 t o 135 kg were p r e s e n t d u r i n g t h e Plant  Tomato p l a n t s  house were s t o c k i e r w i t h d a r k e r g r e e n plants  experiments.  g r o w t h s t u d i e s were p e r f o r m e d  cucumbers and b r o c c o l i .  i n the c o n t r o l  on  i n the attached colored  Then a p p a r e n t l y , t h e y d e v e l o p e d  interveinal  drying  and c u r l i n g  leaves.  fruits  were d i s c o v e r e d t o have b l o s s o m  weeks  later,  house. The  these  symptoms  to unbalanced  greenhouses  c h l o r o s i s and  A week l a t e r , t h e end r o t .  appeared  About  marketable  fruit  from  i n the c o n t r o l  data  (above  result  w h i c h was o v e r  fruit  the c o n t r o l  i n the C0  house.  house  2  was  3 times  house compared t o t h o s e  was  Also, the 4a  house.  grown i n t h e a t t a c h e d g r e e n h o u s e  g r o u n d ) more t h a n  compared t o t h e b r o c c o l i A surprising  the poor  f o r cucumbers grown i n b o t h  t h o s e grown i n t h e c o n t r o l  transplants  tops weight  green-  greenhouses.  i n t h e e x p e r i m e n t a l greenhouse weighed  p e r c e n t p l a n t more t h a n Broccoli  three  fertilization.  showed t h a t m a r k e t a b l e  31 p e r c e n t more t h a n  t h r e e months.  t h e d i s e a s e and e v e n t u a l l y  A n a l y s i s o f the y i e l d  had  also  green-  leaves than  A v e r a g e p r o d u c t i o n was v e r y low i n b o t h  authors a t t r i b u t e d  yield  tomatoes,  greenhouse d u r i n g the f i r s t  o f the lower  and  plants  2 1/2  t i m e s when  grown i n t h e c o n t r o l  house.  n i t r o g e n content i n the b r o c c o l i a s much f o r p l a n t s  tops,  grown i n t h e C 0  grown i n t h e c o n t r o l  greenhouse.  2  PART I ANALYSIS OF THE EFFECT OF SEVERAL CONSTRUCTION PARAMETERS ON THE SOLAR RADIATION INPUT INTO GREENHOUSES  CHAPTER 1 SOLAR RADIATION TRANSMISSION FACTORS OF GREENHOUSES  INTRODUCTION  To  compare  standard  o r bench  latitude, shape the  solar  mark  defined,  calls  material  radiation  input  a method  beam, d i f f u s e transparent  factors  and t o t a l  o f greenhouses.  The s e c o n d  Also,  and t o t a l s o l a r  section,  the t o t a l  leading  A term  which  factor" i s  with  different  locations  the e f f e c t on the s o l a r  the monthly  for their  section  which  average  daily  g i v e s the  factor  to  by the d i f f e r e n t In the l a s t  concept  energy input  transmission  contribution  are investigated.  radiation  first  radiation  radiation  of several  The  o f the g r e e n h o u s e  the r e l a t i v e  transmission  t o a new d e s i g n  greenhouse.  orientation,  sections.  f o r the s o l a r  o f the greenhouse  strategies  three  transmittance  surfaces  investigate  into  for estimating  expressions  beam, d i f f u s e  a  efficiency.  surfaces.  mathematical  transmission  and a t d i f f e r e n t  This chapter i s divided describes  size,  greenhouses  standpoint,  the e f f e c t o f  can be e s t i m a t e d .  t o compare  parameters  energy  so t h a t  availability,  "a g r e e n h o u s e  t h e n used  construction  from a s o l a r  i s required  radiation  and c o v e r i n g  author  solar  greenhouses  i s used t o  conservation into  greenhouses  the author c a l l s  "a s o l a r - s h e d "  SECTION A ESTIMATION OF THE MONTHLY AVERAGE DAILY BEAM, DIFFUSE AND TOTAL TRANSMITTANCE OF THE GREENHOUSE TRANSPARENT SURFACES  TRANSMITTANCE  The calculate the  OF THE GREENHOUSE TRANSPARENT  following section describes  greenhouse c o v e r i n g m a t e r i a l t o s o l a r are required t o estimate  greenhouse t r a n s m i s s i o n this  t h e method u s e d t o  t h e m o n t h l y a v e r a g e beam and t o t a l  average values  chapter  SURFACES  transmittance of  radiation.  These  t h e beam and t o t a l  f a c t o r s as i n d i c a t e d i n S e c t i o n B o f  by e q u a t i o n s  (13) and (15) r e s p e c t i v e l y .  ASSUMPTIONS The  f o l l o w i n g assumptions  the weighted  average d a i l y  a r e made i n o r d e r  beam and t o t a l  to calculate  transmittance  f o r the  greenhouse c o v e r i n g m a t e r i a l s . :  i)  No c o n d e n s a t i o n  or dust  greenhouse c o v e r i n g  ii)  accumulation  such t h a t the transmittance i s  for  the covering material only.  and  reflection  However,  o f the greenhouse  t o the d i f f u s e  covering  component o f r a d i a t i o n i s  i n d e p e n d e n t o f t h e o r i e n t a t i o n and t i l t surface.  absorption  l o s s e s are accounted f o r .  The t r a n s m i t t a n c e material  on t h e  I t i s assumed t o be c o n s t a n t  t h a t o f t h e beam.  o f the and e q u a l t o  THEORETICAL FORMULATION The  *  i n s t a n t a n e o u s beam s o l a r  through a greenhouse t r a n s p a r e n t  then,  radiation  flux  transmitted  cover i s ,  t h e d a i l y e n e r g y w e i g h t e d beam t r a n s m i t t a n c e o f t h e  surface  t o t h e d i r e c t component o f s o l a r  calculated  by i n t e g r a t i n g  sunset  follows:  as  equation  radiation  may be  (1) f r o m s u n r i s e  to  ss b,day  /  ^b*  3  / /  / Since hourly  solar  radiation  basis,  V  w  '  (2)  10 " sr  data are usually  available  on an  t h e d a i l y beam t r a n s m i t t a n c e o f t h e g r e e n h o u s e  covering material  may be a p p r o x i m a t e d b y :  (3)  * The d e f i n i t i o n o f symbols f o u n d on Pages  89 and 90.  used  i n this section  c a n be  For  feasibility  greenhouses, monthly of  studies  of solar  energy  applications  i t i s more i m p o r t a n t t o be a b l e  to estimate  a v e r a g e d a i l y beam and t o t a l  the transparent  greenhouse  to  t r a n s m i t t a n c e f o r each  s u r f a c e s which  are location  dependent. For and  locations  total  monthly  where b o t h m o n t h l y  i n s o l a t i o n on a h o r i z o n t a l  average h o u r l y  estimated using  diffuse  monthly  average d a i l y  discussion results Here, H /H d  is  used  (1978).  solar  (1960).  radiation  data are i n  i n s o l a t i o n on a  horizontal  radiation  into  i t s two  e q u a t i o n s have b e e n p r o p o s e d f o r (1960) , Page  Iqbal  (1961) , T u l l e r  (1978) g i v e s  of these c o r r e l a t i o n s ,  including  a  detailed  a comparison o f  o b t a i n e d by e a c h o f t h e s e methods. Iqbal s 1  correlation equation,  = 0.958 - 0.982 K~  T  (  4  )  throughout the a n a l y s i s .  When t h e m o n t h l y insolation monthly  total  ( L i u and J o r d a n  (1976) a n d I q b a l  a r e known, t h e  e q u a t i o n s must be u s e d t o s e p a r a t e t h e  Many e m p i r i c a l  such a purpose  the  average t o t a l  correlation  components.  solar  diffuse  i n s o l a t i o n may be  t h e L i u and J o r d a n method  form o f monthly  surface,  surface  and t o t a l  S i n c e most w i d e l y a v a i l a b l e the  average d a i l y  average h o u r l y  on a h o r i z o n t a l  surface  a v e r a g e h o u r l y beam s o l a r  diffuse  and t o t a l  a r e known, t h e n t h e radiation  incident  on a  tilted  surface  " i " o f the g r e e n h o u s e  Ib,i  = (I ~ I d ) R b , i  where  R  = cos8j/cose  where  cos6 =  and  5 / i  cos^i  =  costf^  sin*  Also, the  cos*  n  cos 6 cosw + sin<j> sin<5  +  cosw  c o s Y i sin<f  +  cos<5 s i n t f i  cos<5 s i n ^ i sinYi  + cosSi) H  solar  radiation  on  ar "aH .ii a i ec assumed assuiuea  components  s u r f a c e , the monthly  greenhouse  s u r f a c e s may  ss  =  S  +(1/2) o ( l - c o s t i i J H . (9)  d  the s k y - d i f f u s e r a d i a t i o n  Knowing t h e d i f f e r e n t  ' i  diffuse  (8)  surface i s ,  g r o u n d r e f l e— c— <t .e ud u j r. aa di i- aj t. iu oi ni  be e s t i m a t e d  /  f o r the m o n t h l y  '  beam  on  the  transmittance  as f o l l o w s :  ss  X)  b , i b,i 1  H,, and t h e d isotropic.  o f the r a d i a t i o n  average d a i l y  _ T  sr  and  sinu> .  average d a i l y  In t h i s e q u a t i o n ,  b  (7)  sin<$ sin<p  COSU)  1  T  (6)  n  cos<S cos«p c o s t f i  Hd,i=( /2)d  of  (5)  cos<p s i n t f ^ COSY i  the m o n t h l y  tilted  r  +  tilted  i s d e t e r m i n e d as f o l l o w s :  X  b,i  (i ) 0  sr  average d a i l y  total  transmittance,  T .  (ID  1  where  (12)  is  the d a i l y  transparent The function of  takes For  surface, i .  o f the a n g l e and  described  the d i f f u s e  transmittance  of incidence  i t s thickness by D u f f i e  i n t o account  assumed  s o l a r r a d i a t i o n i n c i d e n t on t h e g r e e n h o u s e  beam and d i f f u s e  the g l a s s  method  total  both  t o be c o n s t a n t  sake  of  completeness.  method  losses.  of incidence i s  t o be e q u a l  i s included  the  This  and a b s o r p t i o n  the a n g l e  and t a k e n  (1974).  as a  properties  are c a l c u l a t e d using  reflection  summary o f the above method  and the o p t i c a l  and Beckman  transmittance  f o r tne g l a s s  to 58°.  A  i n Appendix A f o r the  SECTION B ESTIMATION OF THE MONTHLY AVERAGE DAILY BEAM, DIFFUSE AND TOTAL TRANSMISSION FACTORS OF GREENHOUSES  SOLAR RADIATION TRANSMISSION FACTORS OF GREENHOUSES  DEFINITIONS OF TRANSMISSION FACTORS * The ratio  greenhouse  o f the s o l a r e n e r g y  covering equal  transmission  system  to that  to the f l o o r  absence  diffuse  transmitted  surface  area  surfaces  As  f o r each  radiation,  then  which  be d e f i n e d  could  BEAM TRANSMISSION  we have  w i t h the  covering  o f beam and has a  different  o f t h e two components o f  two d i s t i n c t  transmission  factors  as f o l l o w s :  FACTOR (BTF)  Beam s o l a r r a d i a t i o n t r a n s m i t t e d t h r o u g h the t r a n s l u c e n t greenhouse c o v e r i n g BTF  = O u t s i d e beam s o l a r r a d i a t i o n i n c i d e n t on a h o r i z o n t a l s u r f a c e equal to the f l o o r o f the g r e e n h o u s e  BTF  =  n _ _ EAT H i b,ib,i i =1  * The d e f i n i t i o n  A H f b  ' •  o f symbols  f o u n d on Pages 89 and 90.  area  solar radiation  i s composed  r a d i a t i o n and the t r a n s p a r e n t value  the g r e e n h o u s e  o f the g r e e n h o u s e  covering.  o f the g r e e n h o u s e  transmittance  through  as t h e  i n c i d e n t on a h o r i z o n t a l s u r f a c e  o f the g r e e n h o u s e  incident  factor i s defined  used  (13)  i n t h i s s e c t i o n c a n be  DIFFUSE TRANSMISSION Diffuse DTF  DTF  =  O u t s i d e d i f f u s e s o l a r r a d i a t i o n i n c i d e n t on a h o r i z o n t a l s u r f a c e e q u a l t o the f l o o r o f t h e greenhouse. n _ _ I A x H i d,i d, i i =1 . (14) A H f d  Knowing  FACTOR ( T T F )  the beam and d i f f u s e  transmission  defined  s o l a r r a d i a t i o n t r a n s m i t t e d through the translucent greenhouse c o v e r i n g  =  TOTAL TRANSMISSION  total  FACTOR (DTF)  factor  in a similar  transmission  f o r the g r e e n h o u s e  factors,  may  also  a  be  manner.  Total TTF =  TTF  s o l a r r a d i a t i o n t r a n s m i t t e d through the translucent greenhouse c o v e r i n g . O u t s i d e t o t a l s o l a r r a d i a t i o n i n c i d e n t on a h o r i z o n t a l s u r f a c e equal to the f l o o r o f the greenhouse  n £ A T H i i i i=1 A H f  n S A T H i b, i b, i + i=1 A H f  n Z i=1  A (15)  DESCRIPTION OF THE COMPUTER MODEL FOR TRANSMISSION A solar  computer energy  greenhouse, the  transmitted their  greenhouse  originally minor  as they  surface. are  as l o n g  each  t o compute t h e  o f the s u r f a c e s  factors.  f o r monthly i t could  a l s o handle  i n FORTRAN  The p r o g r a m  average  be used  daily  was  values,  for specific  as they  are f l a t ,  any number o f c o v e r s  D i f f e r e n t covering  average  materials  daily  a horizontal  surface.  Reflectivity  of  total  surrounding  for different  insolation  on  surfaces to  solar radiation. Input  parameters: 1.  Location  2.  Number  (latitude)  o f the g r e e n h o u s e  of surfaces  which make  up t h e  greenhouse 3.  Orientation, t i l t for  4.  each  and  and number o f  covers  o f the s u r f a c e s  Optical properties  (index  of refraction  extinction coefficient)  as  f o r any p a r t i c u l a r  Input v a r i a b l e s ;  2.  The  any number o f s u r f a c e s p e r  a r e o f t h e same m a t e r i a l  Monthly  but w i t h  days.  permitted.  1.  of a  c o n t r i b u t i o n t o s o l a r i n p u t , and  transmission  modifications  greenhouse  through  percent  written  program w i l l  long  program was w r i t t e n  FACTORS  and  thickness  surfaces  of  greenhouse  covering  of  the s u r f a c e s  material  f o r each  Outputs: 1.  Average  daily  beam, d i f f u s e  transmittance up 2.  and  total  o f each o f s u r f a c e s  making  the g r e e n h o u s e .  Average solar  daily  energy  beam, d i f f u s e transmitted  and  total  through  various  surfaces . 3.  Contribution diffuse  4.  o f each  and t o t a l  t o beam,  s o l a r energy  D a i l y beam, d i f f u s e transmitted  surface  and t o t a l  inputs. s o l a r energy  through the greenhouse  covering. 5.  Average  daily  transmission  SAMPLE OUTPUT;  beam, d i f f u s e  RESULTS AND DISCUSSION g a b l e g l a s s h o u s e was used  The g r e e n h o u s e  length  respectively,  with  The  o f the g r e e n h o u s e  long-axis  cover  total  f a c t o r s f o r the g r e e n h o u s e .  A 500 s q u a r e metre example.  and  a wall  i s s i n g l e g l a s s with  height  as an  and w i d t h a r e 50m and 10m o f 2m and an 18° r o o f i s east-west o r i e n t e d .  the f o l l o w i n g  slope. The  characteristics;  Extinction Index o f  Coefficient  0.161 cm  Refraction  1.526  Location The  i n s o l a t i o n on a  and t h e monthly average ground c o v e r  for  solar  are  indicated The  radiation  (albedo) used as i n p u t  i n Table  calculated  transmittance is  V a n c o u v e r , B.C. (49.25°N)  monthly average d a i l y t o t a l  surface  f o r the s i n g l e  glass  diffuse  c o v e r was 0.818, w h i c h  and t i l t  angles.  and t o t a l  o f t h e o t h e r o u t p u t s o f t h e computer  m o d e l a r e shown f o r December and f o r J u l y 1.3, r e s p e c t i v e l y .  output  It  T h e s e two t a b l e s  purposes.  i n Tables  are included  Appendix B g i v e s a complete  f o r a greenhouse having c o n s t r u c t i o n  described diffuse  transmittance f o r  respectively.  sample o f r e s u l t s  discussion  The m o n t h l y  s u r f a c e s o f t h e g r e e n h o u s e a r e shown i n F i g u r e s  1.1 and 1.2, A  reflectivity  t o t h e program  monthly average d a i l y  independent o f o r i e n t a t i o n  various  horizontal  1.1.  a v e r a g e d a i l y beam t r a n s m i t t a n c e the  1  above. and t o t a l  The t r a n s m i s s i o n solar  i s important  transmission  factor  radiation  to notice  factors  1.2 and  here f o r computer  p a r a m e t e r s as f o r t h e beam,  a r e shown i n F i g u r e  that  the greenhouse  (DTF) r e m a i n s f a i r l y  1.3  diffuse  constant over the  MONTREAL (45.5*N)  EDMONTON (53.5'N)  VANOOUVER (49.25*N)  kJ.B~ " day  kJ.m" day"' a 2  TUSOON (32.5*N)  H  H  H Month  WINNIPEG (50*N)  2  -1  a  "H  kJ.» day"' -2  a  IT  kJ.^day  H -1  a  IT  H"  Jan  5 272  0.32  0.52  5 230  0.32  0.39  3 682  0.32  0.44  2 970  0.18  0.65  13 180  0.30  Feb  8 870  0.33  0.45  9 247  0.33  0.33  6 987  0.33  0.40  5 565  0.17  0.59  16 359  0.30  Mar  14 056  0.25  0.40  14 226  0.25  0.33  12 678  0.25  0.35  10 502  0.12  0.50  22 394  0.23  Apr  lb 192  0.20  0.47  27 447  0.22  0.41  17 615  0.22  0.38  15 188  0.14  0.48  27 425  0.21  May  20 167  0.20  0.45  20 794  0.20  0.42  20 711  0.20  0.42  20 502  0.14  0.43  30 501  0.20  Jun  22 092  0.20  0.43  22 259  0.20  0.43  22 259  0.20  0.42  22 845  0.14  0.41  29 246  0.26  Jul  21 297  0.20  0.44  23 012  0.20  0.39  22 886  0.20  0.39  23 179  0.14  0.38  26 192  0.32  Aug  17 581  0.20  0.47  10 497  0.20  0.39  18 033  0.20  0.42  19 121  0.14  0.41  24 602  0.31  Sep  12 975  0.20  0.46  13 472  0.20  0.44  13 054  0.20  0.42  13 682  0.14  0.44  23 849  0.23  Oct  a 954  0.20  0.50  8 494  0.20  0.46  8 075  0.20  0.42  7 280  0.14  0.54  18 493  0.26  Nov  4 268  0.23  0.64  4 644  0.23  0.51  4 100  0.23  0.47  3 766  0.15  0.61  14 895  0.25  Dec  3 891  0.28  0.59  3 766  0.28  0.47  2 678  0.28  0.49  2 385  0.18  0.67  12 761  0.27  Table  Note:  1.1  M o n t h l y a v e r a g e d a i l y t o t a l i n s o l a t i o n on a h o r i z o n t a l s u r f a c e , g r o u n d a l b e d o and r a t i o o f d i f f u s e t o t o t a l r a d i a t i o n f o r t h e l o c a t i o n s s e l e c t e d f o r t h i s study. T h e v a l u e s f o r H a r e t a k e n f r o m "World H a r e and Hay (19 7 4 ) .  Survey o f C l i m a t o l o g y " , see r e f e r e n c e  - H /H a r e c a l c u l a t e d . d  - F o r s o u r c e o f t h e ground  albedo "a" r e f e r  to the text,  pages  72 & 74  FIGURE  1.1  MONTHLY AVERAGE DAILY BEAM TRANSMITTANCE ( T ^ FOR VARIOUS SURFACES OF A WITH SINGLE GLASS COVER.  GREENHOUSE  TOO  i — i — i — r  951  Vancouver,  UJ  BC (49.25°N)  <J  Z < 90h  <70  Orientationl  —^  LLI  n—  A - . ^ N20  o  <65  N90° E/W20° • a E/W90° S20° o-^S90° t—*  a:  > <  T i l t Angle  60  i  X  Z 55h O 50j  FIGURE  3.. 2:  M  J L I I A M J J MONTH  MONTHLY AVERAGE (T)  FOR VARIOUS  A  J  DAILY TOTAL  S  L O  _L N  D  TRANSMITTANCE  SURFACES OF A GREENHOUSE  WITH SINGLE GLASS  COVER.  VANCOUVER DECEMBER  Area M**2  S o l a r Energy T r a n s m i t t e d (KJ/day) Beaa Diffuse Total  100.  242904.  263.  34297 I .  Beaa  ContrI but i on To TotaI Diffuse Total  82072.  324976.  0.402  0.094  0.2 19  333855.  676826.  0.568  0.380  0.457  0.0  0.380  0.225  263.  0.  333855.  333855.  28.  8962.  22958.  31919.  0.015  0.026  0.022  28.  8962.  22958.  3 19 19.  0.0 15  0.026  0.022  0.  81910.  81910.  0.0  0.093  0.055  I 00.  Total Beam 603799.  T a b l e 1.2  Transmitted Diffuse  TotaI  877607.  48 I 4 0 4 .  BTF 1.519  DTF 1.104  Saaple Computer Output f o r an E-H s i n g l e g l a s s cover (50a x 10m x 2a) and I * Roof Slope SI: S2: S3: BTF DTF TTF  south south north  waI I roof roof  d e f i n e d Eq. I d e f i n e d Eq. 2 d e f i n e d Eq. 3  S4: S5: S6:  east wall w e s t wa I I n o r t h waI I  TTF 1.242  greenhouse  VANCOUVER JULY  S  Area M"2  S o l a r Energy T r a n s m i t t e d (KJ/day) Bean Diffuse Total  100.  348908.  489930.  Beaa  C o n t r i button To T o t a l Diffuse Total  838838.  0.053  0.098  0.072  263  3233063.  I 862202.  5095265.  0.489  0.374  0.439  263.  26 I 3 4 7 6 .  I 862202.  4475678.  0.395  0.374  0.386  28.  165209.  I 37 I 8 0 .  302389.  0.025  0.028  0.026  28.  I 65209.  I 37 I 8 0 .  302389.  0.025  0.028  0.026  I 00.  89404 .  489930.  573349 .  0.014  0.098  0.050  Total Beam 66 I 5 2 6 8 .  T a b l e 1.3  Transmitted D i ffuse 4978622.  TotaI  BTF  1 1593892 .  0.927  DTF I . II 8  Saaple Computer Output f o r an E-W s i n g l e g l a s s cover (50a x I OB X 2a) and 18* Roof Slope S I S2 S3 BTF DTF TTF  south south north  wa I I roof roof  defined defined defined  Eq. I Eq. 2 Eq. 3  S4 S5 S6  e a s t waI I west wa I I n o r t h waI  TTF I .000  greenhouse  FIGURE  1.3:  MONTHLY AVERAGE DAILY BEAM (DTF) AND TOTAL  (BTF),  DIFFUSE  (TTF) SOLAR TRANSMISSION  FACTORS FOR A GABLE  GREENHOUSE.  year,  since  independent beam  the g l a s s  transmittance  o f the i n c i d e n c e  transmission  factor  angle.  to d i f f u s e  radiation i s  However,  the g r e e n h o u s e  (BTF) i s h i g h  during  the w i n t e r  months  (November, December, J a n u a r y  and F e b r u a r y ) ,  during  t h e summer  (BTF) d u r i n g  months  f o r an e a s t - w e s t  beam and  transmittance high  The h i g h  oriented  o f the s o u t h  greenhouse roof  contribution  1.2 shows  that  o f the two s o u t h  input  transmittance  i s 97%.  and s o u t h  surfaces  wall  wall  (Fig.1.1)  surfaces  f o r December t h e  F o r t h e summer  o f the s o u t h  winter  i s due t o h i g h  s o l a r r a d i a t i o n i n c i d e n t on the s o u t h Table  radiation  months.  but low  t o the t o t a l months  decreases  beam  the d a i l y  beam  ( F i g . 1.1) and t h e  beam r a d i a t i o n i n c i d e n t on t h e s o u t h  surfaces  (Table  (BTF) f o r the summer  1.3) which  months. south  explains  the l o w e r  F o r t h e month o f J u l y  surfaces  t o the t o t a l  beam s o l a r r a d i a t i o n i n p u t i s  54.2% as compared t o 97% f o r December.  high  greenhouse  winter the  period  high  component  decreases  t h e c o n t r i b u t i o n o f the two  only  total  also  transmission  f o r an e a s t - w e s t  of solar r a d i a t i o n .  the  f a c t o r (TTF) d u r i n g the  oriented  c o n t r i b u t i o n o f the s o u t h  Therefore,  greenhouse  surfaces  i s due t o  t o the beam  SECTION C USE OF THE TOTAL TRANSMISSION FACTOR TO COMPARE GREENHOUSES FOR THEIR SOLAR RADIATION INPUT EFFICIENCY  USE OF THE TOTAL TRANSMISSION  The  percent  a greenhouse calculated  loss or gain  radiation  "y" as compared t o a g r e e n h o u s e  from t h e i r  transmission  i n solar  FACTOR  factors  greenhouse t o t a l (TTF) a s  (TTF)  to  "x" may be  solar  radiation  follows:  - (TTF)  x  input  y  % LOSS/GAIN =  X 100. (TTF) x  EFFECT OF ORIENTATION ON THE GREENHOUSE T T F Figure orientation energy  input  1.4  shows t h e e f f e c t o f n o r t h - s o u t h and e a s t - w e s t  on t h e t o t a l i s higher  summer f o r t h e E-W  orientation  than  radiation  f o r t h e N-S input  ( 1 . 0 2 - 1 . 2 1 / 1 . 0 2 ) x l 0 0 = 18.6% h i g h e r  h o u s e , b u t i t i s 6.6% E-W  oriented  the  heating  heat l o s s  lower  The t o t a l  solar  greenhouse r e q u i r e s  less  orientation.  t o t h e E-W  than  greenhouse  f o r t h e N-S  i n J u n e and J u l y .  green-  T h e r e f o r e , an  supplemental heat  during  s e a s o n and l e s s v e n t i l a t i o n i n t h e summer i f t h e  from t h e greenhouse  orientation.  factor.  i n t h e w i n t e r months and l o w e r i n t h e  During January, the s o l a r is  transmission  i s assumed t o be i n d e p e n d e n t o f  FIGURE  1.4:  EFFECT OF E-W  AND N-S ORIENTATION ON THE  TOTAL TRANSMISSION FACTOR GABLE  GREENHOUSE.  (TTF) FOR A  EFFECT OF DOUBLE GLAZING ON THE GREENHOUSE T T F The  effect  o f d o u b l e g l a z i n g on s o l a r  to t h e greenhouse energy  i s shown i n F i g u r e  i n p u t due t o d o u b l e g l a z i n g i s o n l y  e c o n o m i c s must be c o n s i d e r e d cost  1.5.  o f energy w i l l  double g l a z i n g . reduction  offset  Also,  radiation  input  The l o s s o f s o l a r 13%.  However,  such t h a t t h e s a v i n g s  i n the  the increase i n c a p i t a l  cost f o r  l o s s o f p r o d u c t i v i t y due t o l i g h t  i n the double glazed  g r e e n h o u s e must be c o n s i d e r e d .  EFFECT OF OPAQUE NORTH WALL ON THE TTF OF AN EAST-WEST GLASSHOUSE The with  effect  o f c o v e r i n g t h e n o r t h w a l l o f a greenhouse  opaque i n s u l a t i o n  theoretically Wilson  on t h e h e a t i n g  by C h a n d r a e t a l . ( 1 9 7 6 ) a n d e x p e r i m e n t a l l y by  et al.(1977).  The p e r c e n t  reduction i n heating  ments i s p r o p o r t i o n a l t o t h e r e l a t i v e wall  to the t o t a l  Wilson  exposed  e t al.(1977)  greenhouse w i t h method  l o a d was i n v e s t i g a t e d  found  surface area  surface area o f the north o f the greenhouse.  no c h a n g e i n l i g h t  an opaque n o r t h w a l l .  levels  i n p u t due t o t h e opaque i n s u l a t i o n  of  an E a s t - W e s t o r i e n t e d g r e e n h o u s e .  is  diffuse  radiation.  Therefore,  a n a r r o w band n e a r t h e n o r t h w a l l .  i n the  The T r a n s m i s s i o n  ( F i g u r e 1.6) p r e d i c t s a 5.6% l o s s o f t o t a l  radiation  require-  solar  o f the north  Virtually  i t s effect  Factors  a l l this  wall loss  i s restricted to  FIGURE  1.5:  E F F E C T OF DOUBLE GLAZING OF AN E-W  ORIENTED  GLASSHOUSE ON THE TOTAL TRANSMISSION FACTOR (TTF).  FIGURE  1.6:  EFFECT OF INSULATING THE NORTH WALL OR NORTH WALL AND.ROOF OF AN E-W  ORIENTED  GLASSHOUSE ON THE TOTAL TRANSMISSION FACTOR  (TTF).  EFFECT OF OPAQUE NORTH WALL AND NORTH ROOF ON THE T T F OF AN EAST-WEST GLASSHOUSE Insulating or p a r t i a l l y et  with  a l . (1977).  solar  energy  insulation. calculated  the north wall  Figure  with  1.6, t h e a v e r a g e  t o be i n t h e o r d e r  this  loss i n  system o f  l o s s e s may be  o f 25% f o r J a n u a r y and i n c r e a s i n g  i n J u n e f o r a g r e e n h o u s e l o c a t e d a t V a n c o u v e r , B.C. a l l the north  wall  and r o o f b e i n g  I n a d d i t i o n , one e x p e c t s a s h a d i n g times o f the year,  intransparent.  problem during  d e p e n d i n g on t h e l a t i t u d e  A movable o r a d j u s t a b l e shading  totally  1.6 shows t h a t a c o n s i d e r a b l e  i n p u t may be e x p e r i e n c e d  (49.25°N) w i t h  the  roof  an opaque m a t e r i a l was p r o p o s e d by W i l s o n  From F i g u r e  t o a b o u t 5 0%  and t h e n o r t h  opaque i n s u l a t i o n  most  o f t h e greenhouse.  system might  alleviate  problem.  EFFECT OF LOCATION ON THE GREENHOUSE T T F An  east-west o r i e n t e d greenhouse  analyzed the  f o r four d i f f e r e n t  effect  of latitude  s o l a r energy  input  terms o f d a i l y Figure on  1.7.  The  values  and s o l a r r a d i a t i o n a v a i l a b i l i t y  transmission  The r e s u l t s  on t h e  expressed i n  factors are included i n  The m o n t h l y a v e r a g e d a i l y  a horizontal surface  variables  l o c a t i o n s i n Canada, t o determine  t o a greenhouse.  total  (100m x 10m x 2m) was  total  solar radiation  and t h e g r o u n d a l b e d o u s e d a s i n p u t  t o t h e computer model a r e i n c l u d e d f o r t h e ground albedo  for  Montreal  i n T a b l e 1.1.  FIGURE  1.7:  EFFECT OF LOCATION OF AN E-W  ORIENTED  GLASSHOUSE ON THE TOTAL TRANSMISSION FACTOR  (TTF).  were t a k e n f r o m Hay were assumed t o be  (1976)  and t h o s e o f W i n n i p e g and Edmonton were  t h e same as t h o s e o f M o n t r e a l w h i l e  V a n c o u v e r were f r o m H a r e  & Hay  estimation  a l b e d o on  o f the g r o u n d  a greenhouse  i s e x p e c t e d t o be  of  the r e f l e c t e d  on  the v a r i o u s  especially the  roof  on  and  shows t h a t  component  surfaces the r o o f  ground  will  factors,  especially  locations  have  studied,  small  i s only  during  (TTF),  while  (TTF).  F o r example,  located  the w i n t e r  transmission affected  by  difference  f o r Edmonton.  f a c t o r i s not the l a t i t u d e  1.7  different transmission Among  the  four  has  the  the l o w e s t  used  f o r Vancouver, The  analysis  16% f o r  greenhouse  total  o f i t s l o c a t i o n as shown by Winnipeg  and V a n c o u v e r  a t a p p r o x i m a t e l y t h e same l a t i t u d e ,  weather  factors  weather  f a c t o r s on  ( i . e .cloud,  smog e t c . ) .  s o l a r r a d i a t i o n may  to t o t a l  in this  only  i n (TTF) between  of d i f f u s e  Figure  f o r the month o f J a n u a r y , the  located  ratio  between  a t Edmonton  M o n t r e a l and V a n c o u v e r  f o r M o n t r e a l than 25%  slope.  at a  located  is  and  factor  period.  f a c t o r f o r the g r e e n h o u s e  Winnipeg  i s small,  solar radiation  transmission 1% h i g h e r  to  solar radiation incident  f o r a 20°  the g r e e n h o u s e  input  the c o n t r i b u t i o n  the c o n f i g u r a t i o n 0.03  different  highest  since  o f the g r e e n h o u s e where  of e r r o r s i n the  the s o l a r e n e r g y  to t o t a l  the same g r e e n h o u s e  location  ( 1 9 7 4 ) . The e f f e c t s  those of  insolation  effect  be e s t i m a t e d  H /H. d  which  but a l s o  The  The  the are  by of by  the  calculated  values  of these  values  suggest  transmission the  ratios  and  capture  area,  thus  for Montreal. radiation  20%  H^/H  with  input  lower r a t i o s  the  construction increases  improving  the  the w i n t e r  to the that  increase  favouring  shed  the  f o r the  gable  months o v e r . t h e  facing  summer months, t h e  greenhouse.  input gable  same The  t o the  shed  to  the 1.8  solar order  expected greenhouse  greenhouse  i s about  1.8). shed d e s i g n  may  be  at the  the  opaque n o r t h  upper p o r t i o n o f  i s the  facility  i n t e g r a t e d w i t h i n the  by  greenhouse  wall.  BRACE GREENHOUSE B r a c e g r e e n h o u s e was  (1975) a t t h e specifically  Brace Research conceived  Brace greenhouse  g r e e n h o u s e must be insulated  south  shown i n F i g u r e  which a s o l a r c o l l e c t o r  The  the  greenhouse i s i n the  Another advantage of the  SHED VS.  conventional  solar r a d i a t i o n input  months, as  i n s o l a r energy  winter  (Figure  o f the  These  solar radiation  a greenhouse from a  However, d u r i n g  o f m a g n i t u d e as  during  and  shape o f  greenhouse d u r i n g  average  between t o t a l  1.1.  GABLE GREENHOUSE  t o a shed type  surface  i n Table  factor.  Changing the gable  included  a correlation  transmission  SHED VS.  are  and  d e v e l o p e d by Institute.  for cold climate  T.A.  The  Lawand e t a l .  design  regions.  A  was diagram  i s shown i n F i g u r e  1.8  (Shape B ) .  east-west o r i e n t e d with  the  north  sloped  a t an  angle  equal  t o the  sun's  wall zenith.  The  MONTH FIGURE  1.8:  COMPARISON FACTORS TYPE  OF THE TOTAL TRANSMISSION  (TTF) FOR GABLE, BRACE AND  SHED-  GREENHOUSES.  * % Solar Radiation Shed v s G a b l e  Input Gain/Loss f o r  angle during north wall material plant  t h e summer s o l s t i c e .  i s covered with a solar  ( i . e . aluminum f o i l )  inner  surface o f the  radiation  to d i r e c t  reflection  r a d i a t i o n on  to the  canopy. The  transmission  t h e B r a c e and input  f a c t o r method  the shed greenhouse  efficiency  results  for their  1.8  factors  that  inclusive), while  f o r B r a c e and  period  during  the Brace  the shed  i s equivalent  EFFECT OF The  LOCATION ON  were c a l c u l a t e d  average for five  total  t o 53.5°N  f o r a shed g r e e n h o u s e  degrees  and  results  Table  1.1.  The  are based  ground  to  that  from  (May  greenhouse that to  to the gable  same  August green-  radiation.  Thus,  than the gable or  shed  requirement f o r v e n t i l a t i o n .  factors  (TTF)  having l a t i t u d e s ranging (Edmonton, A l t a . ) .  having a roof  the n o r t h w a l l  These  during  transmission  locations  results  1.9.  seen  total  SHED GREENHOUSE TTF  ( T u s c o n , AZ.)  only  The  ( O c t o b e r t o March  solar  i s more e f f i c i e n t  to i t s lower energy  monthly  radiation  When t h e  to the gable  t h e s h e d becomes e q u i v a l e n t  due  f r o m 32.5°N  i t c a n be  D u r i n g t h e warm months  greenhouse  greenhouse  1.8.  radiation  house w h i l e the B r a c e c a p t u r e s l e s s the Brace  solar  s h e d a r e compared  t h e c o l d months  a d m i t s more s o l a r  o f the y e a r .  inclusive),  t o compare  as a f u n c t i o n o f t h e t i m e o f t h e y e a r .  a c o n v e n t i o n a l gable greenhouse,  Figure  i s used here  f o r M o n t r e a l a r e shown i n F i g u r e  transmission of  The  insulated  slope of  The  20  a r e shown i n F i g u r e  on d a t a f o r H and a  a l b e d o f o r T u s c o n was  as g i v e n i n  assumed t o be  N D J MONTH FIGURE  1.9:  EFFECT OF LOCATION ON THE TOTAL TRANSMISSION FACTOR  (TTF) FOR A SHED-TYPE GREENHOUSE.  constant  over  the year  A simultaneous indicates  clearly  Krp on t h e t o t a l fect  five  a total  examination the e f f e c t  and K t on  factor.  factor  pronounced. Montreal the  It is interesting  f o r t h e month  relatively  high  The e f f e c t  be seen  by c o m p a r i n g  roximately  the same l a t i t u d e ,  than  that  Winnipeg  ponding  these  f o r a l l the  the w i n t e r  t h e low  months  cloudiness  months,  more (TTF) f o r  can be e x p l a i n e d  on  by  for that  (TTF) can a l s o  f o r Vancouver with  those  of  a r e l o c a t e d a t apptransmission  factors  are s i g n i f i c a n t l y  f o r Vancouver. Examination has l o w e r  i n t h e summer,  index  the t o t a l  the w i n t e r  the e f -  ( K ^ = 0.64)  two c i t i e s  index  of Table  indices during  high-  1.1 i n d i c a t e s the c o r r e s -  months.  The the  though  during  those  index  the r e s u l t s  Even  Winnipeg  which  1.9  and c l o u d i n e s s  (TTF) becomes  o f the c l o u d i n e s s  Winnipeg.  for  on  o f November  and F i g u r e  close to unity  to n o t i c e  cloudiness  month.  1.1  As e x p e c t e d ,  However, d u r i n g  i n f l u e n c e o f K-p and l a t i t u d e  the  er  of Table  (TTF) i s s m a l l  transmission  locations studied.  t o 0.20.  of latitude  transmission  of latitude  giving  and e q u a l  influence of latitude  results  of Tuscon, Winnipeg  simultaneously December,  (Figure  the average  1.9  ( T T F ) can e a s i l y and Edmonton  and T a b l e  total  is practically  t h e same  and  (Figure  However  Tuscon  Edmonton,  1.9).  when compared  higher r e s p e c t i v e l y .  a r e examined  1 . 1 ) . F o r t h e month o f  transmission  greenhouse  be s e e n i f  factor  for Montreal,  f o r t h e shed Vancouver  ( T T F ) f o r W i n n i p e g and  to that o f Montreal,  a r e 23% and 37%  EFFECT OF WALLS ON  THE  The and  the  The by the  TTF  and  shed  total  of a  greenhouse  wall  the  the  greenhouse months and  a south  height  i s i n the decreased  contribution  be  a reduction  of  order  WEST  w a l l , east greenhouse  2  example  the  to  beam,  structure  of  20  transparent  as  1.10.  metres  long  degrees  from  s e c t i o n of  the  metres.  the  c o n t r i b u t i o n of  the  s o l a r r a d i a t i o n input of  during  to a l o w v a l u e  of only  3 percent  decrease  i n the  a t t r i b u t e d to  south  into  percent  i n the  walls  in Figure  i s 100  slope  west  the  i n t o the  i s depicted  roof  and  20  This  can  of  t o be  component  summer p e r i o d .  causing  The  year  in this  1.10 shows t h a t  direct  south  shed-type  used  i s assumed  Figure  the  s o l a r r a d i a t i o n input  time o f  horizontal.  OPAQUE EAST AND  A SHED GREENHOUSE  m e t r e s wide w i t h  south  to  roof  v a r i e s with  10  OF  c o n t r i b u t i o n of south  diffuse it  LENGTH, WIDTH AND  the  wall  the  winter during  the  beam r a d i a t i o n  the  high  incidence  beam t r a n s m i t t a n c e  of  the  angle south  cover. On the  diffuse  fairly of  the  12  percent.  The  hand, the  component  constant  constant  to  other  diffuse  of  the  year  is a direct  transmittance  c o n t r i b u t i o n of  the  s o l a r r a d i a t i o n input  throughout This  c o n t r i b u t i o n of  the  beam s o l a r r a d i a t i o n i n p u t  at  an  result  of  same w a l l remained  approximate the  the  covering  east  and  west w a l l s  the  shed  value  assumed  of  to  to  material. combined  greenhouse  is  LU  CD  I— ZD  PQ Q£ I—  o  <c o CO  FIGURE  1.10:  CONTRIBUTION BY THE DIFFERENT SURFACES OF A SHED-TYPE GREENHOUSE FOR THE BEAM  (a),  SOLAR RADIATION BY MONTH.  DIFFUSE (b) AND  (Location:  TOTAL (c)  Montreal,  Quebec).  00 I—'  very  small  Figure diffuse  t h r o u g h o u t t h e y e a r as i s c l e a r l y  1.10(a).  The  component  c o n t r i b u t i o n of these walls  is slightly  component, b u t s t i l l Figure east  1.10(b).  seen  slope  results  Figure  direct  of greenhouse, the  be made opaque w i t h o u t a solar radiation input,  as c a n be  (TTF) o f a 10 m e t r e w i d e  1.11  that  i n c r e a s i n g the length east  total  west w a l l s  20  1.11.  I t i s c l e a r from  o f the shed  f o r the r e l a t i v e l y  shorter  to the l a r g e c o n t r i b u t i o n of d i f f u s e through the east  r a d i a t i o n input  greenhouse  greenhouses. solar radiation  and w e s t w a l l s when compared  t o the greenhouse.  I f the east  average t o t a l  f a c t o r s become t h e same f o r any g r e e n h o u s e this  implies that  of  shed greenhouse  trans-  daily  o f t h e s h e d g r e e n h o u s e were i n s u l a t e d w i t h  Obviously,  The  f i g u r e are f o r a  The d e c r e a s e i n t h e  opaque m a t e r i a l , t h e n t h e m o n t h l y d a i l y  a short  degree  and w e s t w a l l d e c r e a s e s t h e t o t a l  factor significantly.  i s due  and  i s shown i n F i g u r e  l o c a t e d i n the Montreal r e g i o n .  i s more p r o n o u n c e d  mission  solar radiation  i n d i c a t e d i n t h e above m e n t i o n e d  transmitted the  size  o f l e n g t h on t h e t o t a l  factor  transparent  mission  This  f o r the  low as c a n be d e p i c t e d i n  for this  shed-type greenhouse  greenhouse  TTF  than that  to the  from F i g u r e 1 . 1 0 ( c ) .  transmission  with  Therefore,  loss of t o t a l  The e f f e c t  roof  higher  relatively  and w e s t w a l l s c o u l d  significant  i n d i c a t e d by  insulating  results  the east  to and  an trans-  length.  and w e s t  walls  i n a s i g n i f i c a n t decrease i n s o l a r  2.2  en  o I— (_>  CO  co  CO  — I CD  LU CD  UJ  0-8  F  M  A  M  J  J  A  S  O  N  MONTH Figure  1.11:  EFFECT OF LENGTH AND  INSULATING THE  EAST AND WEST WALLS OF A SHED-TYPE GREENHOUSE ON ITS TOTAL TRANSMISSION FACTOR.  (Location:  Montreal,  Quebec)  FIGURE  1.12:  CONTRIBUTION OF THE EAST AND WEST WALLS OF A SHED-TYPE GREENHOUSE TO THE DIFFUSE AND TOTAL SOLAR RADIATION INPUT AS A FUNCTION OF GREENHOUSE LENGTH.  (Location:  Montreal,  Quebec).  MONTH FIGURE  1.13:  EFFECT OF LENGTH, WIDTH AND EAST AND  INSULATING  WEST WALLS OF AN E-W  GREENHOUSE ON  SHED  ITS MONTHLY AVERAGE DAILY  TOTAL TRANSMISSION Curves A & B Curves C & D  FACTOR  (TTF).  North Wall I n s u l a t e d N, E & W W a l l s I n s u l a t e d  Other C o n s t r u c t i o n Parameters: Roof S l o p e : 20° South W a l l Height: 2 m Covering Material: S i n g l e Layer Location:  M o n t r e a l , Quebec.  Glass  energy  input  The  above 1.12,  Figure percent  According of  to  the  total  of  the  diffuse above  a  be  the  of  the  radiation  of  the  solar  a  of  on  the  radiation the  of  length  west w a l l s  shed  input. west  metres  or  than 5 p e r c e n t )  in  of  small  loss  (less  width  of  shed-type  east  the  and  length  the  a  transmission  width  factor  from  10  metres  i n a maximum d e c r e a s e  of  the  This  contribution  of  solar  radiation  the  south  roof  to  examination  insulating  having  percent.  relative  and  total  figure,  by  effect  east  and  seen  50  input.  Doubling  resulted  better  indicates  in only  effect  solar  1.13.  can  greenhouse  radiation The  9  the  a shed  more r e s u l t s solar  fact  which  to  1.11).  i t (Fig.  contribution  greenhouse  walls  to  decrease  i s due  for  to  the  i s shown i n to  20  lower  through  case  of  the  on  TTF  the  Figure  metres  greenhouse  the  input  greenhouse  has of  only  south  wall  percent the  wider  greenhouse. CONCLUSIONS Using  the  total  transmission  following  conclusions  were drawn  as  their  radiation  far  as  solar  factor for  input  as  single  a criterion, span  the  glasshouses  efficiency  was  concerned. 1.  An  east-west  solar  oriented  radiation  oriented  during  greenhouse.  greenhouse the  winter  captures than a  more north-south  2.  Double g l a z i n g energy input compared  3.  Opaque i n s u l a t i o n  the  to  solar  i s diffuse  of the north wall  near the n o r t h  a shed  floor  and r o o f  greenhouse r e s u l t s radiation  and  transmission  Doubling  factor  i n TTF i s f o u n d  10 t o 20m,  studied,  the s o l a r  energy  input  the heating  greenhouse.  i n the length o f a shed-type  i n a decrease  0.05% p e r m e t r e  (Figure  i n a considerable  t o 50% i n J u n e .  to a gable  an i n c r e a s e  o f an e a s t -  F o r the greenhouse  area b a s i s ,  than that  a l l this  i s restricted  type greenhouse i s h i g h e r d u r i n g  In g e n e r a l ,  decrease  input.  6% l o s s i n  wall.  of the north wall  f r o m 29% i n J a n u a r y  On a p e r u n i t  than  and i t s e f f e c t  energy  l o s s was  g r e e n h o u s e as  Virtually  loss  i n solar  solar  o f an e a s t - w e s t  gable greenhouse r e s u l t s  season p e r i o d  7.  input.  radiation,  a narrow r e g i o n  of  cover.  west o r i e n t e d  to  6.  glass  radiation  Opaque i n s u l a t i o n  the 5.  i n 13% l o s s  gable greenhouse causes l e s s  total  loss  results  t o an e a s t - w e s t o r i e n t e d  to single  oriented  4.  (glass)  i n the t o t a l  (TTF).  This  solar  rate of  t o be i n t h e o r d e r o f 1%,  0.25%  f o r t h e greenhouse l e n g t h ranges o f  20 t o 50m  and 50 t o 100m,  respectively  1.11). the width  f r o m 10 t o 20m o f a 100m  t y p e g r e e n h o u s e has d e c r e a s e d  long  t h e T T F by l e s s  shed-  than  9%.  8.  Opaque i n s u l a t i o n  of  the  type greenhouse r e s u l t s total is 9.  radiation  k e p t above 50  The be  solar  total  function solar  of  and  in only  input  west w a l l s o f  a slight  (<5%)  a  decrease  provided  its  shedin  length  metres.  greenhouse t o t a l a  east  transmission  latitude  radiation  on  and  the  factor ratio  a horizontal  was of  found  to  diffuse  to  surface.  NOMENCLATURE Symbol  Definition  Units  A^  - area o f greenhouse  A.  - area o f a s p e c i f i c surface /-r v* /~\ <r\ T-\ V-\ /~\ n n / ~ i g r e e n h o u s e e<\ n»-\c<<~l» 1os-\s u•»r•»e  b'  H  b  H  H  H  d'  ~  H  i ' d i ' ' ' H  H  m  i~  "i"  o f the m  l y a v e r a g e d a i l y beam, d i f f u s e and t o t a l r a d i a t i o n i n c i d e n t o n a horizontal surface outside the greenhouse, r e s p e c t i v e l y  o  m  m -  floor  n  t  I  b  I  b t  kJ-m~  l - y a v e r a g e beam, d i f f u s e a n d t o t a l r a d i a t i o n i n c i d e n t on a s p e c i f i c s u r f a c e " i " o f the greenhouse e n c l o s u r e , -2 respectively kJ.m  o  n  t  n  ~ i n s t a n t a n e o u s beam r a d i a t i o n on a s p e c i f i c s u r f a c e  incident  ~ i t a n e o u s beam r a d i a t i o n through the s p e c i f i c surface  transmitted  n s t a n  >  - h o u r l y beam r a d i a t i o n surface  incident  / kj/  on a  m o n t h l y a v e r a g e h o u r l y beam r a d i a t i o n i n c i d e n t on a s p e c i f i c s u r f a c e " i " o f the greenhouse e n c l o s u r e - monthly average h o u r l y d i f f u s e r a d i a t i o n i n c i d e n t on a h o r i z o n t a l s u r f a c e o u t s i d e the greenhouse  I d  monthly average h o u r l y t o t a l r a d i a t i o n i n c i d e n t on a h o r i z o n t a l s u r f a c e o u t s i d e the greenhouse - cloudiness  K T  R  b,i  :  b'  ~  *b' b , d a y ~ T  r  i  2  n  - m o n t h l y a v e r a g e da daily extraterrestrial s o l a r r a d i a t i o n on a h o r i z o n t a l s u r f a c e  q  2  index  (K  T  =  H/H ) o  i ° o f beam r a d i a t i o n on a t tii l t e d s u r f a c e " i " t o t h a t o n aa hhoorriizzco n t a l surface, respectively a  t  e o u s , a v e r a g e h o u r l y and average d a i l y t r a n s m i t t a n c e o f a t r a n s p a r e n t s u r f a c e t o beam s o l a r radiation respectively  n  s  t  a  n  t  a  n  kJ  b,i  e  d,i  i  monthly average d a i l y t r a n s m i t t a n c e o f a s p e c i f i c s u r f a c e " i " t o beam, d i f f u s e and t o t a l s o l a r r a d i a t i o n respectively s o l a r r a d i a t i o n i n c i d e n c e angle a horizontal surface  h  0. 1  4>  radians  l a t i t u d e angle greenhouse)  radians  hour  ( l o c a t i o n of  Y•  a  the  angle  radians  angle  radians  t i l t angle of a s p e c i f i c surface of the greenhouse e n c l o s u r e ( v e r t i c a l , e = 90°)  1  , a)  radians  s o l a r r a d i a t i o n incidence angle with respect to a s p e c i f i c surface " i " of the greenhouse e n c l o s u r e  sun's d e c l i n a t i o n  UJ  for  "i" radians  - o r i e n t a t i o n angle of a s p e c i f i c s u r f a c e " i " of the greenhouse e n c l o s u r e ( s o u t h , y = 0°)  radians  - s u n r i s e and s u n s e t respectively  radians  - ground  albedo  hour  near the  angles greenhouse  CHAPTER 2 TOTAL SOLAR RADIATION CAPTURE FACTORS OF GREENHOUSES  INTRODUCTION  This chapter discusses the d i f f u s e losses is  from greenhouses.  devoted  The f i r s t  t o the s p e c i a l  two s o u r c e s o f d i f f u s e from t h e gable  roof  section  losses  and i n d i r e c t l o s s  floor.  account, the t o t a l  solar  previously  i n chapter  factor  The of  radiation  given  second  calculating  c a n o p y and t h e  transmission  1 i s modified capture  f o r the solar  the r a d i a t i o n  factor  factor".  radiation  of t h i s chapter  A  total  capture  greenhouse.  introduces  configuration  into  t o g i v e what t h e  f o r the case o f a gable  section  loss  radiation  T a k i n g t h e s e two l o s s e s  "a g r e e n h o u s e t o t a l  i s also  direct  of diffuse  uncovered greenhouse  mathematical expression  of the chapter  are i d e n t i f i e d :  albedo o f the plant  author c a l l s  radiation  c a s e o f a g a b l e g r e e n h o u s e where  due t o t h e e f f e c t i v e  defined  solar  factors  a method f o r green-  house a p p l i c a t i o n s .  Numerical values o f the  factors  f o r t h e e s t i m a t i o n o f the greenhouse  capture  are required factors.  configuration  SECTION A TOTAL CAPTURE FACTORS FOR GABLE GREENHOUSES  TOTAL CAPTURE FACTORS FOR GABLE  The  greenhouse  previously losses plant  a  does n o t t a k e  through canopy.  will  the r o o f These  be c o n s i d e r e d  gable  total  transmission into  GREENHOUSES  factor  account  as d e f i n e d  the d i f f u s e  and t h e r e f l e c t i o n l o s s e s  two s o u r c e s  of solar  i n the f o l l o w i n g  radiation from the  radiation  chapter  loss  f o r the case o f  greenhouse.  ASSUMPTIONS With  respect  t o the d e r i v a t i o n  radiation  capture  factor,  o f the g r e e n h o u s e  the f o l l o w i n g  solar  assumptions are  made: i)  Only  glass ii)  the a b s o r p t i o n  and r e f l e c t i o n l o s s e s  cover are accounted  No c o n d e n s a t i o n  o f the  for.  or dust  accumulation  on t h e g l a s s  cover. iii)  The e f f e c t  o f the s t r u c t u r a l  i v ) A l l the beam r a d i a t i o n glass  cover  plants v)  i s incident  and low r o o f  Plant  reflection  frame  transmitted  on p l a n t  i s neglected. through the  canopy  (i.e.tall  slope). for solar  radiation  is perfectly  diffused. vii) the  Multiple greenhouse  reflection  reflections cover  between  are neglected  i s considered).  the p l a n t (only  canopy and  the f i r s t  THEORETICAL  FORMULATION*  Assumption transmitted  through  p l a n t s . Then incident  (iv) states  that  a l l the beam r a d i a t i o n  any g r e e n h o u s e  surface  the beam r a d i a t i o n from  on t h e p l a n t canopy  i r e a c h e s the  surface  i that i s  i s simply,  A. T. .5, . . l b, l b, l But,  only  through  a fraction  the s u r f a c e  the  diffuse  the  plant Ai7  The  (1)  o f the d i f f u s e i i s reaching  r a d i a t i o n from  canopy may d  #  above  i  H  d  /  i  (l  in  - x  expression  d f i  of t a l l  only  such  equal  plant  of  the g r e e n h o u s e  coming the  through  the p l a n t roof,  that  radiation  through  the o t h e r  l o s s through  * The d e f i n i t i o n  f o u n d on Page 113.  f o r the v e r t i c a l that  sur-  a l l the d i f f u s e walls  However,  o f the  i n the c a s e  o f the d i f f u s e r a d i a t i o n  i s transmitted  s i d e o f the r o o f .  the g r e e n h o u s e  o f symbols used  Furthermore,  as tomatoes and  the v e r t i c a l canopy.  slopes are  transmit-  slopes.  such  implies  a fraction  two r o o f  the d i f f u s e  to zero  from one s i d e o f the r o o f  outside  i f the  canopies,  o f the g r e e n h o u s e , which transmitted  i s i n c i d e n t on  by  f o r both  faces  reaches  i which  (2)  the f a c t o r F i s c l o s e  greenhouse  Therefore,  F).  roses,  radiation  the p l a n t s .  surface  is valid  can be c o n s i d e r e d  the case  transmitted  be r e p r e s e n t e d  made o f the same m a t e r i a l tance  radiation  roof  i n this  and l o s t t o The d i f f u s e  i s represented  s e c t i o n c a n be  in  equation  (2)  by  the  term which i s p r o p o r t i o n a l  to  T,  . F,  Q , I  where F two  i s the  slopes  of  calculated A  the  using  summary o f  greenhouse r o o f . the  the  configuration this  radiation configuration  factors  i s discussed  total  Feingold  in a later  s o l a r r a d i a t i o n f r o m any i s i n c i d e n t on  calculated  using  equations  =  Ex. . H. . b,i b,i  A. i  H. i  The  A. l  total  be  (1966).  greenhouse section  multiplying  A  i  5  i  In e q u a t i o n the  plant  -  1  canopy  original  p  T  due  d,i  4 only  sketch  1 and +  T  plant  2 as  of  to  }  the  below.  3 by  canopy i s  plant  then  -F)]. d,i  the  (3)  plant  surface  can  factor  albedo,  to  be  i  for  give,  ( 4 )  first Also,  of  calculated  ' reflection the  i s assumed t o be  incident  the  T,  -  a correction  the  i of  follows:  . .H. . (1 d,i d,i  i s a b s o r b e d by  equation  losses  (  the  surface  s o l a r r a d i a t i o n c o m i n g f r o m any  greenhouse t h a t  reflection  in  by  i t s a p p l i c a t i o n to  greenhouse which  by  f a c t o r F may  the  chapter. The  the  The  method d e s c r i b e d  method and  f a c t o r between  i s considered  as  r e f l e c t e d r a d i a t i o n by  diffused regardless  of  shown  the  the  radiation. PT, .A.H i ' d, l I cover (diffuse transmittance, d, i  plant (effective  canopy albedo,  p)  Now,  a "total  g r e e n h o u s e may captured  outside  greenhouse ground may  radiation  be d e f i n e d  by t h e p l a n t  horizontal  (TCF)  solar  capture  to that  incident  s u r f a c e whose a r e a  as  total  energy  on a  i s equal  The g r e e n h o u s e  be c a l c u l a t e d  f o r the  as t h e r a t i o o f t h e s o l a r  canopy  area.  factor"  to the capture  factor  follows:  n E  A i [ T  b  /  i  H  b  f  +  i  T  d  f  i  H  i ( l - T  d  D  i  F  )] ( l -  P  T  D  i)  1=1 TCF=  The  Af H total  greenhouse locations  and w i t h  RESULTS AND  various  as p a s s i v e  roof  roof  curves  represented  slope,  radiation  canopy  a r e shown  i n the f i g u r e  i n the Vancouver,  loss  their  B.C.  area  as i n d i c a t e d  Figure  The d i r e c t  loss  2.1.  can be seen  transmission  factor  plant  here  from  2.1  (TTF) c u r v e  canopy  albedo  to d i s t i n g u i s h  due t o the e f f e c t i v e  i n Figure  2.1.  greenhouse  on the d i a g r a m i n radiation  by c o m p a r i n g t o the c u r v e  of zero.  i t from  The  and h a v i n g t h e  of solar  Figure  t h r o u g h the  are f o r a gable  parameters  used  etc.)for  collectors.  loss  construction  is  at d i f f e r e n t  construction  energy  and the r a d i a t i o n  o f the p l a n t  effective  for a  greenhouses  greenhouse  solar  of solar  albedo  roof  factor  DISCUSSION  effect  greenhouse  capture  f o r comparing  (i.e. insulation,  effectiveness  located  radiation  i s useful  parameters  The  solar  . (5)  that  t h r o u g h the the t o t a l  f o r an  The word d i r e c t due  t o the  loss  MONTH FIGURE 2.1:  EFFECT OF PLANT ALBEDO ON THE SOLAR RADIATION CAPTURE FACTOR FOR A GABLE GREENHOUSE. Dimensions: 100 m x 10 m Orientation: E-W l o n g - a x i s Cover: S i n g l e L a y e r 3 mm G l a s s Location: V a n c o u v e r , B.C. (49.25°N)  reflection direct  loss  through other  kept  the  roof  in  For the  radiation On  greenhouse  are  the  loss  direct are  plant  the  Experimental greenhouses  the  plant  canopy  to  be  through  purposes.  plant  r e f l e c t i o n as  albedos albedo  of of  In constant  0.1 The  t o t a l capture  losses  were  0.1  found  and  the  roof  slope  this  loss  was  here,  0.3  of  the  seen  total  from is  found  solar  on  loss  objects  inside  Obviously the  due  to  the  and  other  0.3  albedo  are  8 and  respectively  two  for losses  i n terms o f shown 24  due the  in Figure  percent  for  when compared  to  2.1. effective  to  an  zero.  this  analysis,  throughout  the  the  effective  year.  In  the  within  however,  radiation  expressed  albedo of  objects.  were used  solar  be  , reflection  effective  available;  factor to  radiation  effective  readily  illustration  These  any  provided  roof.  the  values  greenhouse  or  r e l a t i v e l y more s i g n i f i c a n t than  the  hypothetical  canopy  plants be  and  values  of  the can  solar  f l o o r and  not  transmitted  greenhouse.  including  are  The  As  five percent  of  canopy.  radiation  reached  cited  d i r e c t l y dependent  canopy  plant  greenhouse.  hand,  found  the  solar  i s small  the  other by  the  of  entering  by  never  example  order  the  the  has  loss  the  reflection  losses  but  this  low.  radiation  inside  2.1,  be  solar  constitutes  object  Figure  to  of  albedo  reality,  i s taken  as  i t s value  is  a  closely  related  development.  to the type o f crop  The e f f e c t i v e  modified  t o improve  factor.  This  for  solar  Q-mats  energy  in  of black  greenhouse with  thermal storage  done w i t h  under  system  i n waste  applications  to g r e e n h o u s e s .  effect  o f the  c o l l e c t o r developed applications, i t are layed  the p l a n t s ,  flat  energy  used  recovery  on  then  the energy c o l l e c t e d  Q-mats a r e a l s o  distribution  capture  greenhouse a l b e d o .  mats which  to t r a n s p o r t tank.  One  f o r greenhouse  and/or  artifically  the use o f Q-mats*  and s t o r a g e .  plastic  be  radiation  name f o r a s o l a r  floor  water  also  solar  i n the e f f e c t i v e  France s p e c i f i c a l l y  filled a  collection  i s a trade  consists the  has been  i s a reduction  Q -mats  albedo could  the greenhouse  indeed  grown and i t s s t a g e o f  to  as a h e a t  SECTION B CALCULATION OF CONFIGURATION FACTORS FOR DIFFUSE RADIATION IN GREENHOUSES  CALCULATION OF CONFIGURATION  In the  the f i r s t  solar  radiation  dependent between  section  t h e two s l o p e s  concentrates  of this  capture  on t h e d i f f u s e  FACTORS  chapter,  factor  radiation  f o r gable  factors  o f the r o o f .  t o be used  found  This  factors  section  to c a l c u l a t e  with  that  greenhouses i s  configuration  on an a n a l y t i c a l method  configuration  i t was  respect  these  to gable  greenhouses. ASSUMPTIONS The  following  derivation for  a r e made w i t h  o f the r a d i a n t - i n t e r c h a n g e  greenhouse i)  assumptions  respect  t o the  configuration  factors  applications:  The r a d i a t i o n  from any s u r f a c e  i is perfectly  diffuse. ii)  The s u r f a c e  is  isothermal.  THEORY* The the  radiation  configuration  f r a c t i o n o f the r a d i a t i o n  surface  A  a r e a A-^ t h a t  geometric  leaving  i s incident  shape  factor  an i s o t h e r m a l  upon a n o t h e r w a l l  commonly p r e s e n t  * The d e f i n i t i o n o f s y m b o l s u s e d be f o u n d on Page 113.  F-|_2 i s d e f i n e d  with  as  wall of of area  respect  i n t h i s s e c t i o n can  to  g r e e n h o u s e s c a n be t r e a t e d edge. angle  a s two r e c t a n g l e s  The s p e c i a l c a s e o f s u c h r e c t a n g l e s leads  textbooks. arbitrary  formula  The g e n e r a l  c a s e o f two r e c t a n g l e s  (1952) who o b t a i n e d  first  by H a m i l t o n and Morgan  (1966) f o r c e r t a i n a n g l e s a n d d i m e n s i o n s .  for  to obtain  detailed  by  Feingold  Unfortunately,  v a l u e s do n o t c o v e r t h e r a n g e o f d i m e n s i o n s  greenhouse a p p l i c a t i o n s .  diffuse  2.2.  f a c t o r s as c a l c u l a t e d  H a m i l t o n and Morgan's e q u a t i o n a r e g i v e n  tabulated  transfer  f o r m i n g an  shown i n F i g u r e  Numerical values o f the c o n f i g u r a t i o n using  i n most h e a t  treated  the expression  a common  forming a r i g h t  to a simple  a n g l e h a s been  found  having  values  f o rconfiguration  radiation analysis analysis  configuration  I t i s the object factors  factors  houses, the reader  useful  of this  section  t o be u s e d f o r  i n gable greenhouses.  and more c o m p r e h e n s i v e  the  For a  results of  f o r t r i a n g u l a r and c i r c u l a r  i s r e f e r r e d t o McAdam e t  roof  green-  al.(1971).  RESULTS AND DISCUSSION The the  expression  configuration  shown i n F i g u r e  2.2 i s u s e d  f a c t o r F between t h e two r o o f  g a b l e g r e e n h o u s e , and t h e c o n f i g u r a t i o n slope  to the plant  configuration  canopy, F'.  factor  ends F" i s c a l c u l a t e d F" The  f r o m one r o o f  of a  f a c t o r f r o m one r o o f  slope  t o t h e two g a b l e  as f o l l o w s : (6)  radiation configuration lengths  slopes  Then, t h e r a d i a t i o n  = 1 - F - F'  greenhouse  t o determine  f a c t o r s are determined f o r  f r o m 10 t o 100 m e t r e s and h a v i n g a w i d t h  f r o m 5 t o 15 m e t r e s w i t h  roof  slopes  chosen t o cover the  L = cjb; N = a/b.  i •• Wb\ l\ - (1+N )V+L*) + it,in ([i ;v2 2 _ ^ . 2  +  + JA  2  sin- <D In  + .V tan-  1  +  Z  2  j  L  J (- 2 _ Y  +i 2  2iVL  (  o  r L (l + A + £ _-2A Lcos_<P) 1 L ) [(l + L*f(N* + L*-ML cos / 2  1«»*.-o»* cot»» +  n  ^ J  s  - ,) ( os  h  T2  2  T  , cos  2  8  z  +t N  £•> J  +  j A Z cos"*) T  +  Ltan j -1  j - V(A' + X - 2A Z, cos 0 ) cot" y/(N + X - 2 AZ, cos «D) 2  2  T  1  + J A sin <D sin 2<J> ^( 1 + iV sin*0 )J *t a n i / 7  s  + cos d) f % ( l Jo  FIGURE 2.2:  + s  A* cos*  2  [  2  2  T  (,7^A' siOT))  WO)ftan-i( L \.V(l+2 sm <I>)/ 2  TWO  + t a n _ 1  2  >  ARBITRARY  ANGLE.* F e i n g o l d , A.  dzl J|  FACTOR BETWEEN  RECTANGLES FORMING AN  * Source:  (vTlTA^n^J  \ /(l + 2 sin*0)/J  s  RADIATION CONFIGURATION  ,/ £-ATcos<t>Y]  \  2  (1966)  range  commonly u s e d by t h e g r e e n h o u s e  slopes  Three  roof  were s e l e c t e d , namely 1 5 ° , 20° and 25° f o r w h i c h t h e  results For  industry.  a r e shown i n F i g u r e s  each roof  slope,  2.3, 2.4 and 2.5, r e s p e c t i v e l y .  the values  f u n c t i o n o f greenhouse  length  o f F and F " a r e p l o t t e d as a  and w i d t h .  The e f f e c t  of roof  slope  on t h e r a d i a t i o n c o n f i g u r a t i o n f a c t o r s c a n be s e e n i n  Table  2.1.  EFFECT OF GREENHOUSE WIDTH For  any r o o f  configuration relatively of  20°  slope,  factor.  i n c r e a s i n g the width decreases the  This effect  s h o r t greenhouse.  (Figure  an i n c r e a s e  F o r example,  2.4) and a g r e e n h o u s e  i n the greenhouse  i n a decrease f o r the value  0.05657  t o 0.05298.  a greenhouse  0.0592 and 0.0582  only f o r  f o r a roof  slope  l e n g t h o f 20 m e t r e s ,  w i d t h f r o m 5 t o 10  results  for  i s significant  metres  o f the f a c t o r F from  However, f o r t h e same r o o f  l e n g t h o f 70 m e t r e s ,  slope but  the values  f o r a 5 and 10 m e t r e s  o f F become  greenhouse  width  respectively. E F F E C T OF GREENHOUSE For  roof  slopes  LENGTH and w i d t h s i n v e s t i g a t e d , t h e c o n f i g u r a t i o n  f a c t o r F i s found t o i n c r e a s e w i t h i n c r e a s i n g greenhouse The  rate of increase  greenhouses.  of F with length  For long  the  value  the  g a b l e ends w h i c h  greenhouses,  o f F becomes s m a l l .  This  becomes v e r y  length.  i s larger f o r shorter  the e f f e c t  o f l e n g t h on  i s due t o t h e e f f e c t o f  small  f o r the long  ROOF  H O  a  M M  U)  td  > do  n  OF RE  W O  to  M 3 a  CO  fi  W 3  o G  >-3 PC  cn cn PC M  >  2! a S! H  TH  > < M z o a > PC o o 2 o  CD  m m o cr CO  m m CD i—  ,  ,  1  >  TT  m m —i  O 2!  ES  i— Ul  >  o>  CA DI  OF  w  cn  —1  M  o  —  O n W o W  *3 H  CD  w (O  O  9QT  M O  c! W  >  w  00 M  o  JO  O  3  tr  1  o a G  cn w cn <  TO > 25 D  H  25  CD CO  o a O O  o  CD  >-3  a cn fO w ss m W o H  O  >  O  O 25  H  a o M o a 25 M M  cn  H O  a  •-3  H  O 25 > O i-3 O  cn *j  O  LOT  3>  m co  H  o G  8  f W O » M  >  M O  •-3  O hi  i-3  JO o o a o  o H  >  t-3  o  80T  g r e e n h o u s e s as d e p i c t e d values and  2.3 t o 2.5 by t h e s m a l l  o f the c o n f i g u r a t i o n f a c t o r s  the gable  take  i n Figures  ends F".  F o r the purpose o f  f o r example a g r e e n h o u s e h a v i n g  d e g r e e s and a w i d t h o f 10 m e t r e s ; can  be s e e n t h a t t h e v a l u e  0.0573 f o r an i n c r e a s e  100 m e t r e s ,  the values  a roof  of F increases  i n length  slope  illustration, slope  t h e n by F i g u r e  o f 20 2.4 i t  f r o m 0.0466 t o  f r o m 10 t o 50 m e t r e s .  However, i f t h e g r e e n h o u s e l e n g t h  to  between t h e r o o f  i s increased  o f F has i n c r e a s e d o n l y  f r o m 60 t o from  0.0578  0.0588.  EFFECT OF ROOF SLOPE The of  greenhouse r o o f  slope  has more e f f e c t  the c o n f i g u r a t i o n f a c t o r F than the length  the  greenhouse.  Table  2.1 g i v e s  a f u n c t i o n o f greenhouse l e n g t h constant It much  the values f o r three  i s important  of the roof  to notice that  of. F and F " as  roof  than those slope.  the values  slopes  and a  This  s h o r t greenhouses d u r i n g (TCF) d e f i n e d  greenhouses  regardless  implies that the r a d i a t i o n when d e a l i n g  the c a l c u l a t i o n  i n the previous  the f r a c t i o n  of r a d i a t i o n  slope  that  through  i s lost  section.  2%.  Therefore,  transmitted  the gable equation  loss with  of the t o t a l  capture  In long  ( s a y > 50 m e t r e s ) t h e e n d e f f e c t s may  since  than  o f F" a r e  o f F f o r s h o r t greenhouse  f r o m t h e gable, ends must be c o n s i d e r e d  less  and w i d t h o f  w i d t h o f 10 m e t r e s .  higher  factors  on t h e v a l u e  be  neglected  t h r o u g h one r o o f  ends i s e x p e c t e d  t o be  5 f o r the c a l c u l a t i o n of  TABLE  2.1  RADIATION CONFIGURATION FACTORS BETWEEN THE TWO AND  FROM ONE ROOF SLOPE TO GABLE ENDS  SLOPES OF ROOF (F)  (F") FOR A GABLE GREENHOUSE  HAVING A WIDTH OF 10 METRES  Length (m)  1  5  Greenhouse Roof °  °  Slope 25°  2 0  F  F"  F  F"  F  F"  10  0.0264  0.0674  0.0466  0.0902  0.0722  0.1130  20  0.0300  0.0342  0.0530  0.0461  0.0822  0.0581  30  0.0313  0.0229  0.0553  0.0309  0.0859  0.0390  40  0.0320  0.0172  0.0566  0.0232  0.0878  0.0293  50  0.0324  0.0138  0.0573  0.0181  0.0890  0.0235  60  0.0327  0.0115  0.0578  0.0155  0.0898  0.0196  70  0.0329  0.0098  0.0582  0.0133  0.0903  0.0168  80  0.0330  0.0086  0.0584  0.0116  0.0907  0.0147  90  0.0331  0.0077  0.0586  0.0103  0.0911  0.0130  100  0.0332  0.0069  0.0588  0.0093  0.0913  0.0117  the  greenhouse t o t a l  section A of this only, the  For having the  chapter  since during  gable  capture  i s valid  (TCF) as d e r i v e d i n f o r long  greenhouses  t h e d e r i v a t i o n , t h e r a d i a t i o n l o s s by  ends h a s b e e n  neglected.  t h e c a s e o f t h e g r e e n h o u s e shown i n F i g u r e  t h e d i m e n s i o n s o f 100 m x 10 m w i t h  f a c t o r F has a v a l u e  0. 00 8.  factor  Therefore,  o f 0.0477 w h i l e  the e f f e c t  given  slope,  t h a t o f F" i s o n l y  o f F" on t h e r a d i a t i o n l o s s  f r o m t h e g r e e n h o u s e was n o t c o n s i d e r e d thus the r e s u l t s  18° r o o f  2.1,  i n Figure  during  the a n a l y s i s ,  2.1.  CONCLUSIONS B a s e d upon t h e c a l c u l a t e d g r e e n h o u s e c o n f i g u r a t i o n factors  the f o l l o w i n g conclusions  to d i f f u s e 1.  For a given  roof  a decreased  direct  relatively For roof  short  slopes  construction increase  The e x t e n t  r a d i a t i o n l o s s through the  This effect  i s more s i g n i f i c a n t f o r  greenhouses. and w i d t h s commonly u s e d by t h e g r e e n h o u s e  diffuse  of d i r e c t  i s f o u n d t o be more  short  diffuse  greenhouses.  r a d i a t i o n l o s s through the  i s more d e p e n d e n t on i t s r o o f  or width.  tends t o  r a d i a t i o n l o s s through the  This e f f e c t  for relatively  greenhouse r o o f length  i n c r e a s i n g the width r e s u l t s i n  diffuse  the d i r e c t  significant  its  slope,  industry, i n c r e a s i n g the length  greenhouse r o o f .  3.  respect  radiation loss:  greenhouse r o o f .  2.  may be made w i t h  slope  than  5.  of  length  be  neglected.  During  the  capture may (> 6.  The  be 50  and  w i d t h on  calculation  factors  of  the  of  direct loss  the  greenhouses, the  n e g l e c t e d when d e a l i n g m)  having  total  solar  greenhouses are albedo of  the  low  roof  radiation highly  plant  with  slopes  capture  albedo r e s u l t s  thus a  low  solar  radiation  g a b l e ends  effect  greenhouses  factors the  the  diffuse  radiation  radiation  20°).  d e p e n d e n t on  in large  diffuse  solar  long  (<  canopy w i t h i n  A high  total  total  of  (TCF)  of  effective  greenhouse. radiation  capture  factor.  loss,  NOMENCLATURE  A  Units  Definition  Symbol floor  f  area o f a greenhouse  m  A. l  area o f a s p e c i f i c surface greenhouse e n c l o s u r e  F  r a d i a t i o n c o n f i g u r a t i o n f a c t o r between t h e two r o o f s l o p e s o f t h e g r e e n h o u s e  F'  radiation configuration roof slope t o the plant  F"  r a d i a t i o n c o n f i g u r a t i o n f a c t o r f r o m one r o o f s l o p e t o t h e two g a b l e ends monthly  b,i'  d,i  H T  P  ., b,i  average d a i l y  "i"  of the m  f a c t o r f r o m one canopy  insolation  . _ -2 k J .m  m o n t h l y a v e r a g e d a i l y beam a n d d i f f u s e r a d i a t i o n i n c i d e n t on a s p e c i f i c s u r f a c e " i " o f t h e greenhouse e n c l o s u r e , respectively  k J .m  as  k J .m  defined  by e q u a t i o n (3)  T, monthly average d a i l y t r a n s m i t t a n c e of d,i p i f i s u r f a c e " i " t o beam a n d diffuse solar radiation, respectively a  2  S  e  c  c  effective  plant  canopy  albedo  -2 -2  PART II  ANALYSIS OF GREENHOUSE-LIVESTOCK COMBINATION FOR POSSIBLE ENERGY CONSERVATION  CHAPTER 3  COMPUTER SIMULATION MODEL OF ENERGY REQUIREMENTS FOR LIVESTOCK BUILDINGS  INTRODUCTION  The  first  chapter of t h i s study  examine t h e e n e r g y buildings. The of  requirements  I t i s divided  first  section  the mathematical  The  purpose  electrical  i n t o two  sections.  deals primarily  w i t h t h e development  model f o r t h e l i v e s t o c k  required  environment  controlled  the l i v e s t o c k  F a c t o r s c o n s i d e r e d i n t h e c o m p u t e r model are heat  v e n t i l a t i o n , animal  radiation The perform  effects  facility.  development  and l a t e n t h e a t p r o d u c t i o n ,  the b u i l d i n g  envelope,  and s o l a r  l o s s o r g a i n from  the structure.  computer model i n i t s p r e s e n t form  i s designed t o  energy  on h e a t  a n a l y s e s on l i v e s t o c k  intended to p r e d i c t building. the  sensible  t r a n s m i s s i o n through  building.  t h e t h e r m a l and  to provide a  within  intended to  of conventional livestock  o f t h e model i s t o p r e d i c t energy  atmospheric  i s mainly  buildings.  the environmental  I t i s not  c o n d i t i o n s within the  However, w i t h s i m p l e m o d i f i c a t i o n s t o some o f  s u b r o u t i n e s , t h e computer model c o u l d p r e d i c t t h e  inside  temperature  and r e l a t i v e h u m i d i t y o f a  livestock  facility. The varying  model c o u l d be u s e d the o r i e n t a t i o n  building,  t o examine t h e e f f e c t o f  and t h e l e v e l  of i n s u l a t i o n of the  a n d t h e e f f e c t o f v a r y i n g t h e minimum w i n t e r and  t h e maximum summer consumption  v e n t i l a t i o n r a t e s on t h e t o t a l  by t h e l i v e s t o c k  building.  energy  The s e c o n d sol-air heat  methods  transfer  for calculating  about  through  a case  study.  conventional  swine f i n i s h i n g  barn.  t o examine i f e x c e s s of supplying p a r t i a l l y  greenhouse.  from  a  chapter d e s c r i b e s the a p p l i c a t i o n  t h e h e a t i n g and v e n t i l a t i o n  purpose  between t h e r e s u l t s  to those r e s u l t i n g  to determine  analyzed  the t r a n s m i s s i o n  the b u i l d i n g w a l l s i s included.  section of this  t h e c o m p u t e r model  d i s c u s s i o n of the  A comparison  s o l - a i r methods  heat balance  The l a s t of  available  from b u i l d i n g s .  o b t a i n e d by two detailed  section gives a detailed  heat  Also,  The model was  requirements  used  of a  the r e s u l t s are  i s available  f o r the  t h e h e a t i n g l o a d o f an a d j a c e n t  SECTION A  MATHEMATICAL MODEL DEVELOPMENT FOR THE LIVESTOCK BUILDING  MODEL  DEVELOPMENT  ASSUMPTIONS In  d e v e l o p i n g t h e model, s e v e r a l  assumptions  were  made: i)  E f f e c t o f heat  s t o r a g e i n t h e w a l l s and t h e f l o o r  i s neglected. ii)  Heat t r a n s f e r during  through  the f l o o r i s accounted f o r  the heat t r a n s f e r  calculations  through the  perimeter of the building. iii)  Complete m i x i n g o f t h e a i r i n the b u i l d i n g .  iv)  Constant animals  heat  and m o i s t u r e p r o d u c t i o n b y t h e  housed w i t h i n  the b u i l d i n g .  HEAT BALANCE ABOUT THE LIVESTOCK BUILDING When t h e above a s s u m p t i o n s the g e n e r a l heat balance  about  are taken  into  the b u i l d i n g  consideration,  c a n be r e p r e s e n t e d  as: ANIMAL  SENSIBLE HEAT PRODUCTION  + SUPPLEMENTAL HEAT  = HEAT FOR VENTILATION + HEAT TRANSMISSION ; or  i n equation  Q  Details are  SENS  +  form:  Q  SUP  o f each  =  Q  VENT  +  Q  TRAN  o f t h e terms o f t h e energy  represented i n t h i s  chapter.  ^ balance  equation  The  transmission  convective and  and  methods a r e  heat  available  heat t r a n s f e r . is well  (1978) and The effect the  the  outside  of  sol-air by  needs t o be  of  the  on  e f f e c t of on  (.1970) and  to  a wall  solar  c o n v e c t i v e heat t r a n s f e r temperature c o r r e c t e d  the  solar  the  transmission  the The  may  the  rise to  inversely  defined  following  the  to wind. effect  in its  into account  the  e f f e c t of  radiation  the  surface.  by  the the  His  v  above e x p r e s s i o n emission of  modified  to  (2) '  take  long-wave  expression  for  tenperature.is: T  . = ? + sa,i 0  Ca. I . l s,i  e.I„)/h . l I ' w,i  The is  simplest  expression:  n  (1978) m o d i f i e d  solar  proportional  solar radiation be  in  anfl' t o t h e  c o e f f i c i e n t due  for  t e m p e r a t u r e and  and  used  same  . = T + a. I ./h . sa,i 0 l s , i ' w,i  O'Callaghan  Two  (1977).  has  radiation  surface,  by  the  O'Callaghan  Fundamentals  o u t s i d e temperature.  , 1970).  on  t e m p e r a t u r e method i s w i d e l y  a b s o r b e d by  that  building  considered.  building  Threlkeld  surface  incident  T  conductive,  solar radiation  e s t i m a t e the  i n the  a  (Threlkeld  sol-air  also  walls  radiation  termed s o l - a i r form  the  temperature i s d i r e c t l y proportional  absorptivity  to  e f f e c t of  ASHRAE Handbook o f  a rise  outside  radiation  The  the  to  the  described  solar as  The  transfer  e n e r g y a b s o r b e d by  and  includes  r a d i a t i v e h e a t e x c h a n g e between t h e  i t s environment.  transmission  heat t r a n s f e r  (3)  where 1^  i s t h e i n t e n s i t y o f long-wave r a d i a t i o n  b l a c k body a t t h e t e m p e r a t u r e T.£ i s t a k e n as assumed t h a t radiation further  thermal r a d i a t i o n to the sky.  i n Section  of  the b u i l d i n g  on a d e t a i l e d  c a n be u s e d  thermal r a d i a t i o n  For used  the purpose  on  heat balance  ground the  to determine  for digital  computer  of t h i s analysis,  envelope solar  transfer.  calculations.  t h e s e c o n d method i s  consideration  the e f f e c t of  r a d i a n t h e a t exchange t o the e x t e r i o r  sky  surfaces  building. following  g e n e r a l heat b a l a n c e e q u a t i o n about  the o u t e r s u r f a c e s o f the b u i l d i n g  calculate e.o l  the  about  the e f f e c t of  the t r a n s m i s s i o n heat  i n order to take i n t o  The of  discussed  B.  T h i s method i s s u i t a b l e  of  balances  o u t e r s u r f a c e o f e a c h o f t h e w a l l s m a k i n g up  and  and  from the ground  i t is  S o l - a i r methods a r e  A s e c o n d method b a s e d the  a  o f the ambient a i r .  zero f o r a v e r t i c a l w a l l because  lost  from  the s u r f a c e  [T . - 0.5 s,i 4  + h  envelope  i s used  each to  temperatures:  (1 + c o s  • (T . - T_) w,i s,i 0  3.) l  - U. l  T . - 0.5 sky 4  (1 - c o s  0.) l  T ] g 4  (T. - T .) - a. I . = 0 b s,i l s,i (4)  where h  w  , the wind  u s i n g McAdams  heat t r a n s f e r  (1954) h  relationship  = 20.52 + 13.68 w  c o e f f i c i e n t i s estimated  W  .  (5)  e q u a l t o t h e ambient radiation I  s,  incident  . i s calculated  i n Appendix  C.  solar  and o r i e n t a t i o n  The e f f e c t i v e s k y  i s a f u n c t i o n o f many m e t e o r o l o g i c a l  s u c h as w a t e r correlation  The t o t a l  on a s u r f a c e o f a n y t i l t  1  temperature  a i r temperature.  vapour  c o n t e n t and a i r t e m p e r a t u r e .  e q u a t i o n s between t h e e f f e c t i v e  and t h e m e t e o r o l o g i c a l v a r i a b l e s (1932 ), B l i s s  (1961) , Swinbank  Morse and Read  variables  (1968)>.  Several  sky t e m p e r a t u r e  have been p r o p o s e d (1963 ) , W h i l l i e r  In t h i s  analysis,  (Brunt  (1967 ) ,  Swinbank's  correlation  T  relating  = °'  0 5 5 2  the sky temperature  temperature  T  u*  5  C  to the l o c a l  of equation  surface  "i"  (A)  i s required  o f the b u i l d i n g  surface temperature,  temperature  temperature following  T  g  a  =  i t s outer  attic  space, the  c a n be e s t i m a t e d whence t h e o u t e r  of the roof  surface  s u r f a c e s a r e known u s i n g t h e  relationship:  (U A T, + c c b  7  m U.A.T .)/(U A + j 3 s,:)' c c  where U^A^ overall  U.A.) D 3  .  (7)  j=l  a r e f o r the exposed heat t r a n s f e r  >  / v  j=l  The  f o r each  ^.  m  T  )  environmental  t o determine  F o r a b u i l d i n g w i t h an u n v e n t i l a t e d attic  6  i s employed.  Solution exposed  sky  surfaces of the a t t i c  coefficients  space.  U.'s e x c l u d e t h e  outside  film  The and  coefficients.  total  heat  transmission  between t h e b u i l d i n g  i t s e n v i r o n m e n t may t h e n b e c a l c u l a t e d u s i n g t h e  following  equation:  Q  TRAN  =  U  f  A  f  (  V  0  T  )  .  +  p  U  P  (  W  n_  (8) i=l where U.'s a r e t h e o v e r a l l the w a l l s  excluding  t e r m s on t h e r i g h t the  heat  ceiling  heat  transfer coefficients for  the outside hand  loss or gain and. t h e w a l l s  film  coefficients.  The  s i d e o f t h e above e q u a t i o n  by t h e f o u n d a t i o n ,  represent  the perimeter,  the  of the building, respectively.  V E N T I L A T I O N HEAT TRANSFER Ventilation determining  f o r l i v e s t o c k housing  t h e optimum a i r f l o w  air  distribution  the  ventilation  ventilation  system design  within rate  system  r a t e a n d p r o v i d i n g an e v e n  the building.  i s determined  i s properly  involves  In t h i s  study,  only  and i t i s assumed t h a t t h e  designed  f o r good a i r  distribution. Ventilation stages low  d e p e n d i n g on t h e o u t s i d e  outside  control  o f a l i v e s t o c k b u i l d i n g c o n s i s t s o f three  temperature,  within  temperatures,  climatic  ventilation  the b u i l d i n g .  conditions.  i s used  At intermediate  the i n s i d e temperature  For  f o r moisture outside  i s maintained  at i t s  optimum l e v e l the o u t s i d e inside  by i n c r e a s i n g t h e  rate.  temperature approaches o r exceeds the  temperature,  ventilation handbook  ventilation  rate  C1980) and  recommend t y p i c a l based on animal  optimum  animal comfort determines the  (Christianson and-Hellickson, the  required  1977) .  C a n a d i a n Farm B u i l d i n g Code  ventilation  type  When  r a t e s f o r animal  The MWPS*  (1977)  comfort  and s i z e .  VENTILATION SYSTEM CONTROL Ideally, temperature  the  and r e l a t i v e  f o r any o u t s i d e  climatic  possible without  Several building  ventilation  the  system should  humidity  ventilation  control. low f l o w  a constant  rate  high  flow  a thermostat  fan o p e r a t i n g  wiring  levels  This i s obviously  ofa cooling  not  system.  T h e most commonly u s e d r a t e f o r winter  o r two-single  continuously.  some v e n t i l a t i o n  control  v e n t i l a t i o n and  f o r summer v e n t i l a t i o n .  o f s y s t e m c o n t r o l c a n be a c h i e v e d  describes  inside  c o n t r o l s y s t e m s h a v e been u s e d f o r l i v e s t o c k  system i s a c o n s t a n t  and  a t t h e i r optimum  conditions.  installation  keep the  This  by e i t h e r a t w o - s p e e d  speed fans with  The Midwest P l a n  the  type fan  low speed  Service  c o n t r o l s y s t e m s and g i v e s  (19 80) their  diagrams.  For  the  speed f a n s  are  for moisture controlled  purpose o f t h i s selected.  s i m u l a t i o n , two s e t s o f v a r i a b l e  The v a r i a b l e low speed  control during  cold periods.  by a h u m i d i s t a t .  * MWPS: M i d w e s t P l a n  Service  F o r summer  fans  are  These f a n s a r e  ventilation,  used  thermostatically used  to control The  controlled the inside  d e f i n e d below;  from  inside lower  according t o the  relative  balance equation. t h e heat balance  animal comfort.  a t the d e s i r e d  This  predicts fans a r e  level,  resulting  the building.  ina  The a i r f l o w  i n c r e a s i n g o u t s i d e a i r temperature  recommended At this  i s dictated  level  increased to maintain the  humidity within  t o a maximum r a t e  a t an optimum  then the h i g h flow r a t e  increase with  relative  the supplementalsheat  and t h e a i r flow r a t e  temperature  level.  using a moisture  temperature  i s continued u n t i l  temperature  rate w i l l  then,  t h e energy  cooling requirements activated  an optimum  For that  i s determined  t o keep t h e i n s i d e  is calculated procedure  i s determined  humidity allowable.  h u m i d i t y an a i r f l o w r a t e  required  near  fans are  e q u a t i o n when t h e h u m i d i s t a t i s s e t a t t h e  maximum r e l a t i v e  balance  high-speed  temperature  low a i r f l o w r a t e  mass b a l a n c e  variable  by l o c a l  point,  building  the resulting  codes f o r  inside  by t h e o u t s i d e c l i m a t i c  conditions.  VENTILATION RATE FOR HUMIDITY CONTROL The  ventilation  rate  f o rhumidity control  by p e r f o r m i n g a m o i s t u r e b a l a n c e  about  Under n o r m a l  operating conditions,  water v a p o u r  production within  a)  The w a t e r v a p o u r respiration  released  the livestock  building.  t h e r e a r e two s o u r c e s o f  the livestock by t h e a n i m a l s  f o r non-sweating  i s determined  farm  building: through  animals.  b)  The w a t e r v a p o u r the b u i l d i n g ,  The  including  I f we  and r e f e r r e d  let m  building  latent  heat  vaporization  Q  e  = m  where t h e f o r m u l a  moisture  as  latent then  the t o t a l  using the l a t e n t  h_ fg  w  for  known, t h e mass b a l a n c e  heat  ... (9)  i s g i v e n by C o o p e r  of moisture  heat.  follows:  h, = 2504.44 - 2.4 rg  When t h e r a t e  building  produced,  may be c a l c u l a t e d  o f water  surfaces within  production are usually  t o as t h e t o t a l  be t h e t o t a l  w  from wetted  f e c e s and u r i n e .  two s o u r c e s o f w a t e r v a p o u r  combined  of  evaporated  (T, - 2 7 3 . 1 6 ) . b  production within  about  (1969) as  t h e open  (10)  the building i s  system  will  take the  form *a Therefore, moisture  air  as  -  m  a 0 W  +  m  w  '  flow rate  U  required  1  )  t o remove t h e  produced i s (12) a  the sensible  into  rate  b  t h e a i r mass  m Then,  W  heat  the building  of ventilating  lost  due t o t h e i n t r o d u c t i o n  c a n be c a l c u l a t e d  from  t h e mass  of  fresh  flow  a i r and t h e e n t h a l p y change o f t h e a i r  follows:  where the enthalpy of the a i r in the building, h£, i s taken  at t h e barn  dry-bulb temperature  temperature  o f the outside a i r .  The  ventilation rate,  t h e n be c a l c u l a t e d at  the i n s i d e  f o r an exhaust  condition,  .  C14)  required  i s known, t h e s u p p l e m e n t a l  following  Q  inside  temperature  t o remove t h e m o i s t u r e  heat necessary t o maintain  may be e s t i m a t e d f r o m t h e  heat balance e q u a t i o n about SUP  =  Q  may  thus:  Whence, t h e v e n t i l a t i o n r a t e  the d e s i r e d  f a n system,  u s i n g t h e s p e c i f i c volume o f t h e a i r  V = v m /3600  produced  and a t t h e d e w - p o i n t  SENS " TRAN Q  " VENT  the b u i l d i n g *  Q  (  1  5  )  VENTILATION RATE FOR TEMPERATURE CONTROL The  v e n t i l a t i o n rate  i s determined In  required  by p e r f o r m i n g a h e a t b a l a n c e a b o u t  t h i s c a s e , no s u p p l e m e n t a l  ventilation  rate  temperature  a t i t s optimum  The  control  the b u i l d i n g .  i s needed, b u t t h e t o keep t h e i n s i d e  level.  f o r the inside  temperature  S E N S " TRAN  *  c o n t r o l can  as Q  VENT  =  Q  Q  Then, t h e a i r mass f l o w r a t e can be c a l c u l a t e d incoming  heat  must be i n c r e a s e d  heat balance  be w r i t t e n  f o r temperature  fresh  required  (  "  f o r temperature  1 6 )  control  f r o m Qy^jjrp and t h e e n t h a l p y change o f t h e  a i r as  follows:  m  The  a  - VENT Q  / ( h  b- O h  '  )  r e s u l t i n g r e l a t i v e humidity  determined  from t h e s o l u t i o n  Details  (  inside  the b u i l d i n g  o f t h e mass b a l a n c e  o f t h e method u s e d  of  the psychrometric properties  in  Appendix  here  1  7  )  i s then  equation.  f o r the c a l c u l a t i o n  o f moist  a i rare  included  D.  VENTILATION RATE FOR ANIMAL COMFORT The  v e n t i l a t i o n rate  required  periods o f h o t weather i s d i c t a t e d the a n i m a l , building  left  this  simulation  as a parameter  parameters  o f the  system.  model t h e maximum  t o be s e l e c t e d  on t h e p a r t i c u l a r a p p l i c a t i o n  during  by t h e t y p e and age o f  and c o n s t r u c t i o n  and t h e a i r d i s t r i b u t i o n  For is  location  f o r animal comfort  ventilation  by t h e u s e r  rate  depending  o f t h e model.  HEAT AND MOISTURE PRODUCTION BY LIVESTOCK The  use o f the mathematical  model r e q u i r e s  i n f o r m a t i o n on t h e h e a t and m o i s t u r e livestock housed.  confinement  structure  and s i z e o f t h e a n i m a l s  and t h e r e l a t i v e h u m i d i t y w i t h i n management p r a c t i c e s  used  within the  f o r the type o f animals  The h e a t and m o i s t u r e p r o d u c t i o n r a t e  upon t h e b r e e d  facility.  released  accurate  i s dependent  housed, t h e temperature  the building  and upon t h e  i n operating the livestock  Extensive data are a v a i l a b l e of  heat  and w a t e r v a p o u r  livestock. animals to  i s readily  production  g e n e r a t e d by v a r i o u s t y p e s o f  available  environmental  i n many p u b l i c a t i o n s physiology.  related  The b a s a l h e a t  f o r most homeothermes may a l s o be c a l c u l a t e d  the equation developed Data  t h e amounts  The b a s a l h e a t p r o d u c t i o n o f many t y p e s o f  farm animal  using  forpredicting  on t h e s e n s i b l e  individual  animals  by B r o d y  (1945) .  and l a t e n t h e a t p r o d u c t i o n by  are also widely available  f o r most  animals  (Bond  e t al.(1952,  (1960),  Kelly  e t a l . ( 1 9 4 8 ) , L o n g h o u s e e t al.<1960>, O t a e t  a l . (1953),  Restrepo  1959, 1963, 1 9 6 5 ) ,  domestic  e t al.(1977)  However, d a t a o b t a i n e d t h r o u g h suitable  Hazen and M a n g o l d  and R i s k o w s k i  t e s t s on s i n g l e  e t a l . (1977)). animals  f o r the design of heating, v e n t i l a t i n g  conditioning  systems f o r l i v e s t o c k  housing  i s not  and a i r  since  this  type  of  d a t a does n o t r e p r e s e n t t h e a c t u a l o p e r a t i n g c o n d i t i o n s  of  livestock  facilities.  C a r e must be t a k e n when u s i n g p u b l i s h e d r e s e a r c h d a t a on h e a t since  and m o i s t u r e  t h e c o n d i t i o n s under which t h e experiments  conducted  and t h e methods o f measurements u s e d  the r e s u l t s For  p r o d u c t i o n r a t e o f domestic  obtained, thus, t h e i r  range  animals were  influence  of a p p l i c a b i l i t y .  example, when e s t i m a t i n g t h e m o i s t u r e p r o d u c e d ,  i t is  n e c e s s a r y t o d i s t i n g u i s h between a n i m a l m o i s t u r e p r o d u c t i o n and  room m o i s t u r e  vapour  released  production.  by t h e a n i m a l s  The l a t t e r  includes both  and t h e m o i s t u r e  water  evaporated  from t h e w e t t e d waste p r o d u c t s production  s u r f a c e s w i t h i n the ( f e c e s and  urine).  i s more u s e f u l  systems d e s i g n  than  are  animal  experimental  similar  using v a r i a b l e  the d e s i g n the  f  t o be  moisture  ventilating  i n the  to obtain  provided  actual  the  VARIABLE SPEED FANS  speed  from  the  for variable  a i r volume  systems  f a n s as a means o f volume c o n t r o l r a t i o of the  a i r flow d e l i v e r e d  fan.  f o l l o w i n g r e g r e s s i o n equation  Hittle  (1979)  to c a l c u l a t e  the  can to  gives fraction  power:  = 0.00153 + 0.005208 L  In t h e above e q u a t i o n , L the d e l i v e r e d  from  generation alone  adopted  to those used  a i r c a p a c i t y f o r the  of f u l l - l o a d  P  moisture  power r e q u i r e m e n t s  be e s t i m a t e d  room  and  data.  ENERGY CONSUMPTION BY Fan  The  f o r h e a t i n g and  t h e management t e c h n i q u e s building  building  f  f  + 1.1086 L ^ - 0.11635563 L i s the p a r t - l o a d r a t i o  a i r f l o w i n any  p e r i o d o f one  the d e s i g n  a i r flow r a t e f o r the  t h a t L j be  kept  above  0.4.  fan.  3  .  (18)  defined  as  hour d i v i d e d  by  I t i s recommended  SECTION B COMPARISON BETWEEN SOL-AIR AND HEAT BALANCE METHODS FOR TRANSMISSION LOSS CALCULATION  BUILDING TRANSMISSION  LOSS:  SOL-AIR  METHODS VS HEAT BALANCE  In S e c t i o n A o f t h i s two  sol-air  temperature  the t r a n s m i s s i o n heat  section  METHOD  c h a p t e r , i t has been s t a t e d  methods a r e a v a i l a b l e  transfer  e q u a t i o n and 0 ' C a l l a g h a n ' s This  TEMPERATURE  f o restimating  from b u i l d i n g s :  i s devoted  results  o b t a i n e d by t h e two e q u a t i o n s t o t h o s e  farm  equations  t o a d i s c u s s i o n o f t h e two  temperature  a detailed  heat balance  including  about  a comparison o f calculated  the walls o f a t y p i c a l  building.  SOL-AIR TEMPERATURE 1.  Threlkeld,'s  equation.  sol-air  using  that  Threlkeld's  METHODS  Equation:  Threlkeld's  sol-air  by e q u a t i o n 2 o f t h i s thermal  radiation  and s k y .  determined  through  under-estimated. be more p r o n o u n c e d outer  method a s r e p r e s e n t e d  c h a p t e r does n o t t a k e  losses  the ground  temperature  from  the building  into  outer surfaces to  T h e r e f o r e , t h e t r a n s m i s s i o n h e a t as  the use o f e q u a t i o n 2 i s expected The u n d e r - e s t i m a t i o n o f t h e h e a t  t o be  loss  will  i f t h e b u i l d i n g m a t e r i a l m a k i n g up t h e  s u r f a c e o f w a l l s has a h i g h e m i s s i v i t y  radiation.  account the  for infra-red  2.  Q'Callaghan's Equation  temperature  Equation:  3 of  3 by  During following 1.  the  loss  assumptions  surfaces,I  the w a l l  t o t h e sky  from  ground.  For non-vertical  i s represented i n  1  becomes z e r o .  £  This  i s based  the thermal r a d i a t i o n  is offset  by  by t h e  radiative  the surface  the  a b s o l u t e temperature  loss  from  radiative.gain  regardless of t i l t  net  to the f o u r t h  the  of 0 ' C a l l a g h a n s e q u a t i o n the  walls,  loss  loss  of  a r e made:  the argument t h a t  the  compared  o f t h e term E l ^ .  the a p p l i c a t i o n  two  When  from t h e o u t e r s u r f a c e  This  inclusion  For v e r t i c a l upon  2.  heat  t o the s u r r o u n d i n g s .  equation  (1978).  sol-air  equation, 0*Callaghan's e x p r e s s i o n i n c l u d e s  thermal r a d i a t i o n  walls  chapter estimates the  as g i v e n by O ' C a l l a g h a n  with T h r e l k e l d ' s the  this  a n g l e s , the  i s proportional  o f the ambient  power, o r i n e q u a t i o n  to  a i r raised  form, (19)  The  net r a d i a t i v e  the ground The  and  - 0^  <  k  y  loss  from a v e r t i c a l  - 0.5  T<  identical  an e x a m i n a t i o n o f F i g u r e  wall  i n Figure  to  3.1(a)-.  i n t h i s case i s p r o p o r t i o n a l  In order f o r the f i r s t e x p r e s s i o n must be  loss  the sky i s i l l u s t r a t e d  net r a d i a t i v e <  energy  .  assumption to zero.  to:  (20) to hold,  the  In a s i m i l a r  3.1(b) f o r a n o n - v e r t i c a l  above manner, wall  a:VERTICAL  btTILTED  FIGURE. 3.1:  WALL  WALL  THERMAL RADIATION EXCHANGE BETWEEN A WALL AND  ITS ENVIRONMENT.  reveals  that  the net r a d i a t i v e  t h e s k y and g r o u n d T  4  s Therefore  the second  expression It  assumption  (1 - c o s p ) T 9  . (21)  4  i s valid  only  i f t h e above  i s equal to T . 4  i s interesting  of a h o r i z o n t a l valid  from the s u r f a c e t o  i s proportional to:  (1 + cos3)T , - 0.5 sky  - 0.5  4  loss  t o note t h a t  surface,  the second  f o r the s p e c i a l assumption  case  becomes  when, T  4 4 4 - T , = T s sky o  .  (22)  HEAT BALANCE METHOD From t h e above d i s c u s s i o n o f t h e s o l - a i r methods it  for estimating  i s clear  that  are n o t always balance if  about  a digital  method  transmission heat loss  the assumptions  applicable.  underlying  computer i s used.  t o e q u a t i o n 8.  Since,  calculated (i.e.  the surface  temperature  temperature o r assumed.  asphalt  i s preferred  chapter, equation 4  4 for calculating  this  heat  i n Section A of this  T h i s method e l i m i n a t e s  the ground  t h e s e methods  o f the heat balance  t h e two  surface  assumptions  However, i n  1  wall  buildings,  Details  associated with 0'Callaghan s equation. equation  from  Therefore, a detailed  the outer surface of the walls  i s included  temperature  temperature  (T ) a p p e a r s  as an unknown.  i s s e l d o m m e a s u r e d , i t must With  exposed  of the  be  the e x c e p t i o n o f s p e c i a l to sunlight),  the ground  cases  t e m p e r a t u r e may  be c o n s i d e r e d  This  i s not expected  assumption  results  considering  primarily  intended  equal  to the a i r temperature.  to  significantly  a f f e c t the  the a p p l i c a t i o n s of the analyses are f o r r u r a l grass  covered  areas.  COMPARISON OF THE RESULTS BY THE THREE METHODS The is  transmission  calculated using  equation  and  Threlkeld's  The h o u r l y  represent  are given  investigated, the surface In F i g u r e  its  the surface  The c o r r e s p o n d i n g i n Figures  Figure the  Two  3.2.  temperature  The v a l u e s  hourly  heat  transmission indoor  coating are  of radiation properties  on t h e r a d i a t i v e e x c h a n g e . 3.3, t h e a b s o r p t i v i t y f o r s o l a r r a d i a t i o n o f the w a l l s  i s t a k e n as 20 p e r c e n t  while  r a d i a t i o n i s 90 p e r c e n t .  c o n d i t i o n i s representative of white painted 3.4  i n this  f o r a constant  of surface  because o f the e f f e c t  This walls.  i s f o r t h e c a s e where b o t h t h e a b s o r p t i v i t y and  e m i s s i v i t y are equal  t o 20 p e r c e n t .  condition usually represents finish.  l o s s from t h e s e l e c t e d  3.3 and 3.4  types  emissivity to infra-red  surface  surfaces  an a v e r a g e day f o r t h e month o f December i n  temperature o f 18°C.  of  1  about the o u t e r heat  swine b u i l d i n g  0*Callaghan s  i s c a l c u l a t e d f o r the environmental  H a l i f a x area.  losses  of  equation,  s o l a r r a d i a t i o n shown i n F i g u r e  figure the  l o s s from a t y p i c a l  and by a h e a t b a l a n c e  of b u i l d i n g w a l l s . building  heat  This  a b u i l d i n g with  surface aluminum s i d i n g  1  6  FIGURE 3.2:  12  18  24  HOURLY TEMPERATURE AND SOLAR RADIATION ON A HORIZONTAL SURFACE USED FOR THE CALCULATION OF TRANSMISSION HEAT LOSS BY THE SOL-AIR TEMPERATURE AND HEAT BALANCE METHODS.  M U)  ^  An e x a m i n a t i o n equation,  o f F i g u r e 3.3  as e x p e c t e d ,  indicates  under-estimates  that Threlkeld's  the t r a n s m i s s i o n heat  l o s s because i t does n o t c o n s i d e r t h e t h e r m a l loss  from  sol-air higher  temperature than  method. is  loss  This indicates  the roof r a d i a t i v e  the r a d i a t i v e  loss  from  0.9  (Fig.  3.3)  t o 0.2  between t h e r e s u l t s  the d i f f e r e n c e  heat  from  loss  the v e r t i c a l  having  that  a low e m i s s i v i t y  radiative simpler  heat  loss  sol-air  calculate  ( F i g . 3.4), the  f o r t r a n s m i s s i o n heat This further  loss  i s treated.  becomes  less  significant;  from b u i l d i n g s  i n the f i n a l  temperature  t h e h e a t b a l a n c e method i n the comparative  the  thus, the  methods c o u l d be u s e d t o  more c o m p l e x h e a t b a l a n c e method w i t h o u t  The s o l - a i r  Therefore,  f o r long-wave r a d i a t i o n ,  temperature  errors  indicates  f o r w a l l s w i t h an o u t s i d e s u r f a c e  transmission loss  significant  loss  b e t w e e n t h e t h r e e methods i s due t o t h e  by w h i c h t h e r a d i a t i v e  c a n be c o n c l u d e d  trend  balance  t o n o t e when t h e s u r f a c e e m i s s i v i t y  t h e t h r e e methods become s m a l l .  manner  to  heat  as z e r o w i t h t h i s method o f t r a n s m i s s i o n h e a t  i s interesting  reduced  that  0'Callaghan's  transmission values  by t h e d e t a i l e d  that  heat  calculation.  discrepancies  it  equation g i v e s heat  those p r e d i c t e d  i s taken  It  by  On t h e o t h e r h a n d ,  over-estimated, since  walls  is  the s u r f a c e .  radiation  instead  o f the  introducing  results.  methods have a l s o b e e n compared  f o r t h e month o f J u n e .  results  A  similar  to those obtained f o r  December was could  found  be a p p l i e d  i n d i c a t i n g that  to other  t h e above  conclusions  months o f t h e y e a r a s w e l l .  *  HOURLY T R A N S M I S S I O N HEAT LOSS P E R U N I T FLOOR A R E A ( K J . M - 2 )  H  o G 50  1 Ol  M  U)  s: f  >-3 ff  n  cn O  CD  K;  I  o  >  M  >  •  H  50 i-3 W 3 •d  to >  > •= I  O M  o  > W O G ^3  <a -v-  t-3 a  M  t-3 G 50 M  W O G O  1  en  O hj  25 cn  t-3 a w  t-3 K *o  M t-t o  M  o > f  to G H  f a H  3 o  cn O 3 o a o G 50 t-< K  cn 3 H  cn cn H  O 2 a w > t-3 t-t o cn cn > cn  t-t > a  > 3  > a n > t-t o G t-t > t-3. W O  OfrT  H - I—'  H  >  t-3 H  f t-  s > to  I  a  t-i rtiG o £ 3 tr <+ o> 0) 0) •• tr  n o  M  cn t-3 H  t-3 M  O  G cn 3 o  O cr  I—  1  "1  1  1  1  1  P  T  1  1  1  1  1  r  1  1  1  1  1  1  1  r  I  I  L  T =18°C b  Halifax,N.S.  65  December CO  /- N  CD  1  h<C  —>  oo  1  UJ ~r~  <c  CD  1 1, J 11 1  CO CO  ai  sz CO  <c O CD  1  45  i  i —  Length: 100m Width: 11m , 2 T h e r m a l R e s i s t a n c e s (m".K/W) - walls: 2.12 - c e i l i n g : 3.16  >-I or  :=) L U CD  rn  351—  HOUR J  I  L  1  FIGURE 3.4:  J  L  6  J  12  COMPARISON OF HOURLY TRANSMISSION TEMPERATURE  EQUATIONS  (THRELKELD ,  I  L  J  I  18  24  HEAT LOSS AS ESTIMATED USING SOL-AIR 0*CALLAGHAN)  AND  BALANCE ABOUT THE WALLS OF A TYPICAL FARM BUILDING. {a  g  = 0.2;  E  £  =  0.2}  CALCULATED BY HEAT  SECTION C  CASE STUDY I  HEATING AND VENTILATION REQUIREMENTS OF A CONVENTIONAL SWINE FINISHING BARN  DESCRIPTION AND ASSUMPTIONS The of t h i s  computer  c h a p t e r was u s e d t o p r e d i c t  requirement a swine  as w e l l  finishing  the f o l l o w i n g i)  s i m u l a t i o n model d e v e l o p e d  barn.  F o r the purpose  assumptions  heat  rate f o r  o f t h e case  study,  a r e made:  The p i g s e n t e r t h e b u i l d i n g  The s i z e  the supplemental  as the n e c e s s a r y v e n t i l a t i o n  50 k g t o be f i n i s h e d ii)  i n Section A  a t an a v e r a g e w e i g h t o f  t o a market weight  distribution  o f the animals  uniformly  distributed  between s t a r t  such t h a t  t h e average  hog w e i g h t  o f 90 k g .  i n the barn i s and f i n i s h  weight  may be t a k e n a s  70 k g . iii)  The optimum d r y - b u l b t e m p e r a t u r e weight is  iv)  v)  ( T u r n b u l l and B i r d , 1979).  The maximum a l l o w a b l e r e l a t i v e cold  chosen  humidity i n t h e barn  w e a t h e r p e r i o d s i s t a k e n a s 85 p e r c e n t .  The maximum summer v e n t i l a t i o n is  daily  g a i n a n d maximum f e e d c o n v e r s i o n e f f i c i e n c y  t a k e n a s 20°C  during  f o r maximum  a s 0.05 m /s 3  rate  f o r animal  p e r p i g (MWSP-1,  comfort  1980),.  2 vi)  A net f l o o r  space  r e q u i r e m e n t o f 0.6 m  per p i g i s  used. F i g u r e s 3.5and 3.6 show t h e f l o o r view o f t h e f i n i s h i n g used  i n the case  p l a n and t h e c r o s s - s e c t i o n a l  hog b a r n , r e s p e c t i v e l y .  The b u i l d i n g  s t u d y i s 100 m l o n g by 11 m w i d e .  A storage  48  Storage & Isolation  32 Pens  4,8x1,5  4,8  Area «"»  \  Handling  Alley  \  /  Handling 32 Pens  Alley 4,8x1,5  4,8  JL 100m  FIGURE 3.5:  FLOOR PLAN OF THE SWINE FINISHING BARN USED IN CASE STUDY I  FIGURE 3.6:  CROSS-SECTION OF THE SWINE FINISHING BARN USED IN CASE STUDY I .  <_n  and  isolation  into  two  area having a width of 4 m d i v i d e s  e q u a l s e c t i o n s o f 64 p e n s e a c h .  are of equal s i z e Each  pen  houses  number o f a n i m a l s around  1536  an a v e r a g e  the average  12  pigs;  i n the b u i l d i n g  The s t u d y has  total  confinement  a solid  swine  period,  7 980  and  the  m.  total be  Assuming  then  the  hogs.7~  building  concrete floor  m x 1.5  i n s t a n t would  occupied.  o f t e n weeks p e r f i n i s h i n g  e x p e c t e d a n n u a l p r o d u c t i o n w o u l d be  o f 4.8  therefore,  a t any  hogs i f t h e b a r n i s f u l l y  barn  A l l t h e pens  and have t h e d i m e n s i o n s  on  the  chosen  i s well  f o r the  case  insulated.  The  2 resistances  to heat  the c e i l i n g  and  c o n d u c t i o n a r e 5.88  f o r the w a l l s ,  as t h e management p r a c t i c e s u s e d  is  total  h e a t and  room l a t e n t  (1972).  RESULTS AND  t h e hog  simulation  show t h e h o u r l y and d a i l y  transmission ventilation  f o r h e a t and  results  o f e a c h month o f t h e y e a r a r e i n c l u d e d t o F.12  i n Table  well  3.1.  by t h e hogs  Bond e t a l (1959)  barn are i n c l u d e d  as  and  moisture  i n Appendix  E.  DISCUSSION  H o u r l y computer  F.l  for  o f the b u i l d i n g  heat produced  Detailed calculations  production within  K/W  More i n f o r m a t i o n  are included  e s t i m a t e d u s i n g t h e work done by  Carson  4.0m  respectively.  concerning the c o n s t r u c t i o n parameters  The  and  through the b u i l d i n g  for a typical i n Appendix  h e a t l o s s e s due  envelope  f o r t h e o u t s i d e d r y - b u l b and  are indicated  i n the t a b l e s .  The  F.  and  day Tables to  t h o s e due  dew-point  to  temperatures  hourly supplemental  heat  and  TABLE 3.1 VARIABLES  USED TO CALCULATE  HEATING  VENTILATION  REQUIREMENTS OF A CONVENTIONAL SWINE F I N I S H I N G BARN Construction  Parameters  Length: Width: Height; Roof S l o p e : Orientation: Construction Building Component ^ S o u t h Roof N o r t h Roof South W a l l North Wall East Wall West W a l l Gable E a s t End W a l l G a b l e West End W a l l Ceiling Foundation (Insulated)  Long  Axis  Materials Properties Area ,2, (m )  RSI RSI ^ (m K/W)  615 615 200 200 22 22 15  0.19 0.19 4.00 4.00 4. 00 4.00 0.24  18.61 18.61 0.90 0.90 0.90 0.90 15.19  0.2 0.2 0.2 0.2 0.2 0.2 0.2  0.22 0.22 0.22 0.22 0.22 0.22 0.22  15  0.24  15.19  0.2  0.22  1100 111  5.88 1.49  0.61 2.41  Perimeter (Insulated) Management  100 m 11 m 2.5 m 26.57° East-West  222 (m)  2  1.45 (m.K/W)  U -* m" h" K" 1  (kJ  2  1  1  as  2.48 (kJ.m-lh-lK.-l)  Parameters  Location: Number o f h o g s : Average weight: Minimum i n s i d e temperature: Maximum i n s i d e r e l a t i v e h u m i d i t y : Maximum v e n t i l a t i o n r a t e : Ventilation  system  type:  V a n c o u v e r , B.C. M o n t r e a l , Quebec H a l i f a x , N.S. 1536 70 k g 20°C 85% 50 l i t r e s p e r s e c o n d per hog V a r i a b l e speed fans (12 kW p e a k l o a d )  ventilation energy  rate  r e q u i r e m e n t s as w e l l  consumed b y t h e f a n s a r e i n c l u d e d  of Appendix  supplemental heat  i s n o t needed  results  environmental c o n d i t i o n s p r e v i o u s l y hogs p r o d u c e d  the t r a n s m i s s i o n  enough s e n s i b l e heat loss  t h e amount o f v e n t i l a t i o n relative  It  rate  the d e s i g n l e v e l  has r i s e n  and t h e i n s i d e  described  since  and t h e e n e r g y needed a i r that  i s required  July,  the outside  remained  temperature temperature  o c c u r r e d i n t h e d a y t i m e d u r i n g t h e warm  August  and September. rates  t h e month o f J a n u a r y  CFig.  the o u t s i d e d r y - b u l b temperature the v e n t i l a t i o n  a i r i s used  as p r e d i c t e d  3.7 and 3.8,  The c u r v e f o r h o u r l y v e n t i l a t i o n  day d u r i n g  p e r second  The i n c r e a s e o f t h e i n s i d e  by t h e s i m u l a t i o n m o d e l a r e shown i n F i g u r e s  very c l o s e l y  t o keep t h e  temperature  W i n t e r a n d summer h o u r l y v e n t i l a t i o n  a typical  t o heat  t h e recommended  the inside  o f 2 0°C u n t i l  above t h e optimum l e v e l  respectively.  i n T a b l e 3.1.  h e a t t o compensate f o r  t o note t h a t  above 1 8 ° C .  months o f J u n e ,  finishing  f o r a n i m a l c o m f o r t o f 50 l i t r e s  p e r hog i s a d e q u a t e , at  that  h u m i d i t y b e l o w 85 p e r c e n t .  i s interesting  ventilation  indicate  f o r t h e swine  barn w i t h t h e c o n s t r u c t i o n parameters  inside  i n the Tables  F.  As e x p e c t e d , t h e s i m u l a t i o n  The  as t h e e l e c t r i c a l  rates f o r 3.7)  curve  indicates  that  control.  F i g u r e 3.8 shows t h e h o u r l y v e n t i l a t i o n  a typical  day i n August.  follows which  f o r temperature  I t c a n be s e e n t h a t  rates f o r  the v e n t i l a t i o n  1  FIGURE 3.7:  6  12  HOUR  18  24  VENTILATION RATE REQUIREMENT OF THE SWINE FINISHING BARN FOR A MINIMUM INSIDE TEMPERATURE OF 20°C AND A MAXIMUM INSIDE RELATIVE HUMIDITY OF 85% FOR THE OUTSIDE DRY-BULB AND DEW-POINT TEMPERATURES INDICATED IN THE GRAPH.  M  FIGURE 3.8:  VENTILATION RATE REQUIREMENT OF THE SWINE FINISHING BARN FOR A MINIMUM INSIDE TEMPERATURE OF 2 0°C AND A MAXIMUM INSIDE RELATIVE HUMIDITY OF 85% FOR THE OUTSIDE DRY-BULB AND DEW-POINT TEMPERATURES INDICATED IN THE GRAPH.  M °  rate  i s a t i t s maximum v a l u e f o r most o f t h e day  hours  indicating  the s e t p o i n t Appendix  t h a t the i n s i d e  of  may  F a l s o g i v e s the e l e c t r i c a l  16869 kWh barn. under  that was  The  the monthly,  energy consumption  be e s t i m a t e d .  calculated  by  power  then the  By T a b l e s F. 1 t o F.12,  a total  yearly  i t can  annual e l e c t r i c a l  used to v e n t i l a t e  system be  energy o f  the t y p i c a l  swine  finishing  f o r the barn  s t u d y i s i n t h e o r d e r o f 7980 hogs w h i c h  2.11  input  the v e n t i l a t i o n  e x p e c t e d a n n u a l hog p r o d u c t i o n  a ventilation  results in  e n e r g y r e q u i r e m e n t p e r hog p r o d u c e d o f  about  kWh. F i g u r e 3.9 i s a nomograph w h i c h c a n be  to d e t e r m i n e the r e l a t i v e  and t h e m a r k e t can be  cost of  hog.  and  f o r s a l e s v a l u e o f $100  of e l e c t r i c a l  energy used  p e r c e n t o f the market enterprise,  not e x p e c t e d t o a f f e c t  for ventilation value.  By F i g u r e 3.9, i t at six the  represents for a  cost  only  hog  i n the cost o f energy i s  significantly  a direct  manner; b u t , i n d i r e c t l y  the c o s t  o f e n e r g y on f e e d p r i c e s .  o f t h e o p e r a t i n g c o s t o f a hog  p e r hog,  Therefore,  an i n c r e a s e  value  electricity  a t the p r e s e n t c o s t o f e l e c t r i c i t y  c e n t s p e r kWh  finishing  o f the u n i t  value of the f i n i s h e d  seen t h a t  used  c o s t o f energy to the market  o f t h e p r o d u c t as a f u n c t i o n  0.1  i s above  20°C.  to the f a n s from which electrical  temperature  time  the o p e r a t i n g c o s t i n  through the i n f l u e n c e Due  finishing  to the small enterprise  of  fraction that  can  P e r c e n t c o s t o f energy o f t h e market v a l u e  FIGURE 3.9:  Energy r e q u i r e m e n t (kWh p e r hog p r o d u c e d )  NOMOGRAPH FOR DETERMINING THE COST OF ENERGY USED FOR VENTILATION OF SWINE FINISHING BARNS.  I—'  to  be  attributed  combined for  t o energy c o s t ,  greenhouse-livestockbuilding,  the purpose  to  i t i s unlikely  o f energy  that  designed  conservation, w i l l  be  a strictly  beneficial  t h e hog p r o d u c e r . The  amount o f s e n s i b l e  ventilation  heat a v a i l a b l e  a i rforpotential  may be e s t i m a t e d u s i n g  use i n greenhouse  the t o t a l  T a b l e s F . l t o F.12 o f A p p e n d i x  = 3600  The  ventilation  PV C  ventilation  heating  rate  from  F as f o l l o w s :  .  p  rate V varied  i nthe  (23)  f r o m a w i n t e r l o w o f 3.66  m /s 3  3 to  a maximum  first  o f 76.80 m / s d u r i n g  a p p r o x i m a t i o n , assume t h a t  t h e summer m o n t h s .  As a  t h e exhaust a i r from t h e ~—  i  ——  r  swine b u i l d i n g i s a t 20°C a n d s t a n d a r d a t m o s p h e 3r i c p r e s s u r e , than t h e d e n s i t y "p" may be t a k e n a s 1.204 kg/n 1.204 kg/m and t h e specific  heat  Therefore,  " C " a t c o n s t a n t p r e s s u r e a t 1.012 k J / k g . °C. p  t h e amount o f h e a t a v a i l a b l e  "q/AT" i s i n t h e r a n g e o f 16 M J / ° C actual  v a l u e depending  potential will  n o t be u s e f u l  outside heat.  t o 337 M J / ° C  on t h e o u t s i d e  energy since  with the  temperature.  i n t h e upper  s c a l e o f t h e range  does  not require  I t i s e x p e c t e d t h a t most o f t h e energy g a i n  during  building  the spring  will  be f o r m o d e r a t e  and f a l l  periods.  r e c o v e r y from t h e swine  useful  only  The  i t corresponds to periods o f high  t e m p e r a t u r e when t h e g r e e n h o u s e  livestock  heat  available  i n the exhaust a i r  building  when t h e g r e e n h o u s e  outside  Note  that  temperatures direct  ventilation  temperature  from the  waste  system i s  i s below  2 0°C.  CONCLUSIONS The  f o l l o w i n g c o n c l u s i o n s c a n be drawn f r o m  o f t h e s i m u l a t i o n o f h e a t i n g and v e n t i l a t i o n of t h e hog f i n i s h i n g 1.  For a well is  required  relative 2.  finish 3.  described i n this  insulated  building,  f o r an i n s i d e  speed  section:  no s u p p l e m e n t a l  temperature  f a n system,  2.1 kWh o f e l e c t r i c a l a hog from  heat  o f 20°C and a  i t i s found  energy  50 k g t o m a r k e t  The c o s t o f e n e r g y  the operating cost  of  t h e hog m a r k e t v a l u e .  that  i s required to weight.  forventilation  of  based  requirements  h u m i d i t y b e l o w 85 p e r c e n t .  For a variable about  barn  the r e s u l t s  i s a small  fraction  and r e p r e s e n t s o n l y 0.1 p e r c e n t The above e s t i m a t e d v a l u e i s  upon $0.06/kWh f o r e l e c t r i c a l  power and $100 hog  market v a l u e . 4.  The amount o f s e n s i b l e h e a t air  f r o m t h e swine b a r n  337  MJ/°C.  The a c t u a l  available  i s found  i n t h e exhaust  t o be between 16 and  v a l u e depends on t h e o u t s i d e  temperature. 5.  A greenhouse-swine to  t h e hog p r o d u c e r  building  combination  i f o n l y energy  i s not b e n e f i c i a l  i s considered.  NOMENCLATURE Definition A  Surface  area o f the c e i l i n g  m  Surface  area o f the foundation  m  Surface  a r e a o f any w a l l  m  A. 3  Surface  a r e a o f any e x p o s e d  C  Specific  c A, A. 1  "j"  of the a t t i c heat  "i" surface  m  space  of a i r at constant  kJ.kg ^a  - 1  .K  - 1  pressure P  Specific the  h  enthalpy  o f moist  inside dry-bulb  a i r at  kJ.kg ^a  - 1  t e m p e r a t u r e and  b at the dew-point temperature o f t h e outside a i r  h  Specific  0  enthalpy  o f moist  a i r at the  k J . k g ^~ ^a  outside conditions w,  1  Average c o n v e c t i v e heat coefficient outside  h  fg  h  I  L  f  due t o t h e w i n d  s u r f a c e o f any w a l l  L a t e n t heat  k J . h .m" .K 1  2  1  f o r the "i"  o f v a p o r i z a t i o n o f water  kJ.kg  ^ w «_ _ , -1 -2 kJ. h .m 3  Black  body r a d i a t i o n  at the outside 4  dry-bulb S,l  transfer  temperature  Total  solar radiation  wall  "i"  ( 1 ^ = OTQ) incident  , _ , -1 -2 kJ.h .m on any dimensionless  Part-load  ratio  o f t h e f a n d e f i n e d as  the d e l i v e r e d a i r flow d i v i d e d by t h e d e s i g n the f a n  i n any one h o u r a i r flow r a t e f o r  m m  Mass f l o w r a t e o f t h e v e n t i l a t i o n  a  T o t a l moisture produced w i t h i n  w  livestock  kg .h a  the  1  k9 'h ^ w  building  P  B u i l d i n g parameter  Pj  Fraction  of full-load  variable  speed f a n  Q  air  m power f o r a  Sensible heat a v a i l a b l e  dimensionless  i nventilation  kJ.h  1  air Q Q  Total building  e  S E N S  Total the  Q  heat  kJ.h ^  s e n s i b l e heat production w i t h i n  T R A N  kJ.h  1  building  Supplemental heat requirement f o r t h e  s u p  Q  latent  kJ.h ^  livestock  building  Heat l o s s  o r gain  through the b u i l d i n g  kJ.h *  o r gain  due t o v e n t i l a t i o n  kJ.h ^  envelope Q  T  V  E  N  T  Heat l o s s  T  Attic  T^  Inside d r y - b u l b temperature  K  T  Outside d r y - b u l b temperature  K  Effective  K  Q  sky  T  temperature  Sol-air  K  temperature o f the sky  temperature  f o r surface  " i "  K  O u t s i d e s u r f a c e temperature o f any  K  Scl / X  T s/  1  wall T  s  T  i3  "i"  Outside surface  temperature o f any  exposed  "j"  surface  o f the a t t i c  Temperature o f t h e ground g  K  space  at the surface  K  U  Overall the  U.  heat t r a n s f e r  -2  -1 .K -  of  kJ.h  coefficient  of  kJ.h~ .irf .K~  .m  1  1  2  1  foundation  Heat t r a n s f e r " i "  -1  coefficient  ceiling  Overall the  heat t r a n s f e r  coefficient  o f any  e x c l u d i n g the o u t s i d e  wall  kJ.h .m - 1  2  .K  _ 1  film  coefficient U. 3  Heat t r a n s f e r exposed  coefficient  surface  space e x c l u d i n g  o f any  " j " of the  attice  the o u t s i d e  film  -1 .m  kJ.h  -2  x  .K  -1 x  coefficient U  Effective for  heat t r a n s f e r  Ventilation  v  Specific  W  w  b o  v  T  m  rate  volume o f i n s i d e  ventilation Wind  , , -1 -1 -l kJ.h .m .K  the perimeter  V  W  coefficient  a  system) m. s  Humidity r a t i o Humidity r a t i o  .kg" w a -1 kg . k g a ^w a radians  of outside a i r  Slope of surface  "i"  from t h e  horizontal Absorptivity  o f sur f a c e  "i"  to  solar  radiation of surface  radiation  "i"  -1  kg  of inside a i r  r  wave  -1 .s  m 3 .v.k g-1  a i r (exhaust  speed  Emissivity  3  to long-  1  3  -1 Stefan-Boltzmann (a = 20.411 x p AT  constant  kg.m difference  between t h e l i v e s t o c k  building  greenhouse  -4 .K  8  O p e r a t i n g temperature  the  -2 .m  10" )  Density of a i r  and  kJ.h  K  CHAPTER i\  COMPUTER SIMULATION MODEL OF HEATING REQUIREMENTS FOR A CONVENTIONAL GABLE GREENHOUSE  INTRODUCTION  This with two  chapter  respect separate The  i s devoted  t o an a n a l y s i s o f e n e r g y  to a conventional  greenhouse.  first  section deals with  components o f t h e g r e e n h o u s e .  the development o f a  Also  t h e a s s u m p t i o n s made d u r i n g  model  I t consists of  sections.  m a t h e m a t i c a l model u s i n g e n e r g y b a l a n c e s  are  flows  about the d i f f e r e n t  stated i n this  the greenhouse  section,  mathematical  development. In the second  study  are given  computer inside loads.  section, simulation results  f o r a conventional  simulation analyses  greenhouse temperature Also,  house h e a t i n g  the passive requirements  gable  concentrate  glasshouse.  case The  on t h e e f f e c t s o f  and i n f i l t r a t i o n  solar  of a  on t h e h e a t i n g  c o n t r i b u t i o n s t o the green-  f o r d i f f e r e n t minimum  temperatures are i n v e s t i g a t e d i n d e t a i l .  indoor  SECTION A  MATHEMATICAL MODEL DEVELOPMENT FOR THE GABLE GREENHOUSE  "ASSUMPTIONS In d e v e l o p i n g  t h e model,  t h e f o l l o w i n g assumptions  were made: i)  Effect  o f heat storage  i n t h e greenhouse  floor i s  neglected. ii)  Effect  o f shading  by t h e s t r u c t u r a l  frame i s  neglected. iii)  No c o n d e n s a t i o n  or dust  greenhouse c o v e r i n g for  accumulation  such t h a t t h e  on t h e  transmittance  solar radiation i s f o r the covering  material  only. iv)  The g r e e n h o u s e c o v e r i n g m a t e r i a l  i s assumed t o be  opaque t o l o n g wave r a d i a t i o n . v)  The t r a n s m i t t a n c e material  to diffuse  constant  and e q u a l  f o r an a n g l e vi)  r a d i a t i o n i s assumed t o be t o t h a t o f t h e beam  transmittance  o f 1.0123  radians.  The p l a n t canopy r e f l e c t s  diffusely  regardless of  the o r i g i n a l  or d i f f u s e  i n c i d e n t r a d i a t i o n i s beam  i n nature.  Multiple reflection the  viii)  covering  of incidence  whether  vii)  o f the greenhouse  between  greenhouse cover  t h e p l a n t canopy and  i s neglected.  E n e r g y c o n s u m p t i o n by p h o t o s y n t h e s i s evapotranspiration  and  i s assumed t o be n e g l i g i b l e .  The  first  assumption  c a p a c i t y o f the energy if  soil  implies  is negligible  i n p u t to the greenhouse.  the purpose  requirements  that  the heat  relative  to the  T h i s assumption  rather  than  inside  environmental  times or time c o n s t a n t s o f d i f f e r e n t  elements  ( K i n d e l a n , 1980) . second  assumption  may  be  aluminum g r e e n h o u s e s t r u c t u r e s , o c c u p i e d by the t o t a l this  must be  is  justified  since  conditions, heating  for steel  the percentage  area o f the t r a n s p a r e n t c o v e r .  third clean  usually  does n o t e x c e e d  assumption  implies  that  F o r wood  condensation significant  i s concerned,  to  on  The  and  Its effect negligible  Walton,  fourth  with glass  and  transmissivity  solar  the n i g h t heat  l o n g wave r a d i a t i o n  (Walker  i t usually  amount t o a f f e c t  i s mainly  t o be  surface  on h e a t  the greenhouse the case  due  loss  t o t h e low  compared  cover  since As  f a r as  does n o t o c c u r i n a  radiation  loss  to  5 percent.  from d u s t which i s u s u a l l y  greenhouses. found  and  construction  g r e e n h o u s e o p e r a t o r s p e r i o d i c a l l y wash t h e g l a s s .  effect  adequate  s t r u c t u r a l members i s v e r y s m a l l compared  percentage The  daily  o f t h e s i m u l a t i o n m o d e l i s t o compute h e a t i n g  response  The  storage  input.  Its  from p l a s t i c  from  glasshouses  transmissivity  to that  covered  o f some  was  of  glass  plastics  1971).  assumption  is valid  f o r greenhouse  p r o b a b l y p o l y c a r b o n a t e and  fiber  covered  glass.  The  o f t h e above g r e e n h o u s e c o v e r i n g m a t e r i a l s t o  l o n g wave r a d i a t i o n  as m e a s u r e d by Godbey e t a l . (1977) a r e  0.03.  0.06 and f o r g l a s s , p o l y c a r b o n a t e  fiberglass, the  theory  respectively. formulated  accordingly plastic  t o take  film  The  t o l o n g wave  fifth  study  account  covered  greenhouses,  s h o u l d be m o d i f i e d  the t r a n s m i s s i v i t y  of the  radiation.  a s s u m p t i o n was u s e d b y D u f f i e a n d Beckman  (1974) f o r g l a s s c o v e r e d assumed t o e q u a l l y h o l d Assumption be  For polyethylene  i n this  into  and c o r r u g a t e d  solar  collector  f o r glasshouse  Iti s  analyses.  (vi) o f p e r f e c t d i f f u s e  i n serious error provided  analyses.  r e f l e c t i o n may n o t  t h e whole p l a n t canopy i s  considered. The  seventh  reflection  i s considered.  associated with reflection  assumption  implies that only That  multiple reflections  i s negligible,  t h e p l a n t c a n o p y and t h e h i g h  to  solar  (1979),  exchange  compared t o t h e f i r s t absorption  transmittance  of the cover  radiation. h a s b e e n p r o v e n by many r e s e a r c h e r s Walker  photosynthesis, process  radiation  because o f the h i g h  of  It  i s , solar  the f i r s t  (1965))that and e n e r g y  are n e g l i g i b l e  solar  radiation  (Froehlich et a l . u s e d by p l a n t s f o r  released during the r e s p i r a t i o n  relative  t o other  inputs to the  greenhouse.  This j u s t i f i e s  assumption.  On t h e o t h e r h a n d , e v a p o t r a n s p i r a t i o n may be  nificant  part of the eighth sig-  d u r i n g p e r i o d s , t h e g r e e n h o u s e u s u a l l y does n o t r e q u i r e  supplemental piration  the f i r s t  energy  heating.  Therefore,  on e s t i m a t i n g d a i l y  the e f f e c t  heating loads  of  evapotrans-  i s negligible.  HEAT BALANCE ABOUT THE GREENHOUSE When a l l t h e above a s s u m p t i o n s consideration, may be s t a t e d  the heat balance  are taken  into  about t h e greenhouse  as f o l l o w s :  SUPPLEMENTAL HEAT + SOLAR RADIATION INPUT -  INFILTRATION - HEAT TRANSMISSION = 0  or i n equation Q  SOL  +  form:  SUP " I N F  Q  Q  " TRAN Q  °  =  TRANSMISSION HEAT TRANSFER Basically the  l i v e s t o c k b u i l d i n g i s used t o e s t i m a t e  transfer the  by c o n d u c t i o n , c o n v e c t i o n  t h e greenhouse g l a s s  to thermal  is  glass  radiation. cover  environment  This  The o u t s i d e  equation  t h e heat  method i s v a l i d  i s assumed t o be opaque surface  f o r each o f t h e w a l l s  c a l c u l a t e d using  transmission  cover  respect to  and r a d i a t i o n between  g r e e n h o u s e and i t s e n v i r o n m e n t .  since  the  t h e same method e m p l o y e d w i t h  temperature o f  o f t h e greenhouse  (4) o f C h a p t e r  3.  h e a t t r a n s f e r b e t w e e n t h e g r e e n h o u s e and i t s i s c a l c u l a t e d as f o l l o w s :  Q _... = U_A (T -T ,) + U„P U P (T„-T^) (T -T ) + > U.A. TRAN f f g o p g o / J I I T=l m  The  £  heat t r a n s f e r c o e f f i c i e n t  coefficient  Then, t h e  and t h e r e s i s t a n c e  o f any s u r f a c e  U^ i n c l u d e s  the inside  of the covering  i of the greenhouse.  (T -T .) g s,i film  material  (2)  where  R.  =  + R h.  1  The  first  term  on  represents the heat the s e c o n d  term  .  (4)  . the r i g h t  loss  hand s i d e o f e q u a t i o n  or gain through  represents that  and t h e t h i r d  term  t h e w a l l s and  the r o o f of the  the f o u n d a t i o n ,  o f the greenhouse  r e p r e s e n t s the heat  (2)  perimeter,  loss or gain  through  greenhouse.  INFILTRATION HEAT LOSS The  sensible  heat  exfiltration  from  air-exchange  method.  Q  INF  loss  o r g a i n due  to a i r  the greenhouse i s c a l c u l a t e d  P pVa C  =  (  20°C,  u s i n g the  V o> T  ( 5 )  I f t h e a i r i s assumed a t s t a n d a r d p r e s s u r e and of  infiltration/  temperature  then C  p  = 1.012  kJ.kg~ .K~ 1  1  and p = 1.204 and e q u a t i o n  (5) Q  The  INF  ,  - 3  becomes, -  1  '  2  1  8  V  g a N  C  V o T  number o f a i r c h a n g e s f o r any  on t h e s t r u c t u r e , of  kg.m  wind p r o t e c t i o n  differential.  }  ( 6 )  greenhouse w i l l  c o v e r i n g m a t e r i a l , maintenance, and  the  indoor-outdoor  depend the  extent  temperature  Representative values of a i r  infiltration  rates are  t h a t c a n be e x p e c t e d i n v a r i o u s  given  i n a p u b l i c a t i o n by t h e O n t a r i o  Agriculture the  and F o o d * .  estimated  infiltration  F o r newly  a i rinfiltration  1.5 a i r c h a n g e s  p e r hour.  hour,  the  greenhouse  the  infiltration  depending  1.0 a i r c h a n g e s  glazing.  total  and e x f i l t r a t i o n  radiation  i s dependent  of the covering  through each o f  surface  transmitted  material to solar  the s o l a r r a d i a t i o n transmitted  i s treated separately  components o f t h e t o t a l  the v e r t i c a l  envelope.  on t h e f o r m o f t h e o r i g i n a l r a d i a t i o n  on t h e s u r f a c e ,  B  transmitted  the greenhouse i s  s u r f a c e s m a k i n g up t h e g r e e n h o u s e  the t r a n s m i s s i o n  For  f r o m 0.2 t o  GREENHOUSE  solar radiation entering  transparent  and d i f f u s e  r a t e s range  p e r hour.  the  through each  the  F o r p l a s t i c - c o v e r e d greenhouses,  sum o f t h e s o l a r e n e r g y  incident  r a t e i s between 0.75 and  on t h e q u a l i t y o f t h e m a i n t e n a n c e , t o  the  radiation  constructed glasshouses  For o l d glasshouses,  SOLAR ENERGY CAPTURED BY THE  Since  Ministry of  r a t e r a n g e s between 1.0 and 2.0 a i r changes  per  The  types o f greenhouse  walls  f o r t h e beam  insolation.  o f the greenhouse,  t h r o u g h any s u r f a c e  . = B T, . A. w,i v,y b , i l  .  the d i r e c t  "i" is (7)  * Energy C o n s e r v a t i o n i n O n t a r i o Greenhouses. Publication 65. M i n i s t r y o f A g r i c u l t u r e and F o o d , O n t a r i o .  And,  f o r the  d i f f u s e component, t h e  transmitted  through  D  If the of  . = D w,i v,y  " Y " i s the  where  surface  the  T,  d,1  "i"  . A.  i n the  the  be  estimated  where the  greenhouse t h a t  (B  "c"  i s the  + D  w,x  greenhouse are  w,i  (1-C)  .)  First,  radiation  diffuse  the  the  i n c i d e n t on  the  covering  canopy.  plant  G(1-T,  "i"  canopy  i s low  .-a.)]  can  the  of  canopy and  material  plants.  such t h a t  is negligible.  the  the  covering  and  the  that  the  (9)  assumption  material  the  The  total  solar radiation transmitted  vertical  walls  of  g r e e n h o u s e and  of  into  by  account  the  the  simply.  * Derivation  of e q u a t i o n  (9)  i s given  >  multiple  through  captured  to  albedo  takes  reflection.  plant original  c o n t r i b u t i o n of  Equation  is  above  the  second  first  the  to  form of The  "a^"  to s o l a r r a d i a t i o n .  respect  the  (9)*  a , 1 1  the  canopy i s  walls  surface  r a d i a t i o n r e f l e c t e d by  t r a n s m i s s i v i t y of  reflections only  plant  the  then a l l  vertical  through  plant  s o l a r r a d i a t i o n i s high  plants  wall.  tall, the  the  by  [1 +  the  canopy i s d i f f u s e r e g a r d l e s s  that  by  a s s u m p t i o n s a r e made w i t h  equation.  the  through  i s captured  albedo of  a b s o r p t i v i t y of Two  as:  by  . =  w,i  vertical  solar radiation transmitted  the  written  (8)  the  greenhouse i s i n t e r c e p t e d  of  I  be ,  1  solar radiation transmitted  The  is  may  o r i e n t a t i o n of  plants  diffuse solar radiation  i n Appendix  K.  plant  n J  w  The  =  Z i =l  contribution  input  First  the roof  slope  .=B  as  Equation through plant  if  1  ^  (  1  -  T  d , i -  a  i  A  b,j  r->r  the roof  canopy. slopes.  r,j  .+D  1  0  )  energy  i n a similar slope  through  by t h e p l a n t  ) + F  r-*-r  (1-T, .*-a.J  d,j* j *  F  r-*p  canopy  ]  This Also,  assumption only  i s valid  the f i r s t  reflection  o f the opposite roof  transmitted by t h e  for relatively  The " j * " i n e q u a t i o n  of the gable  is  low  considered  (11) i n d i c a t e s slope  a r e used  a r e n o t o f t h e same  material.  The t o t a l  gable  o f t h e g r e e n h o u s e and i n t e r c e p t e d  i s calculated  (11)*  a l l t h e beam r a d i a t i o n  o f the greenhouse i s i n t e r c e p t e d  t h e two s l o p e s  summation  (  . T, .A d,j r,j  r,j  the r a d i a t i o n p r o p e r t i e s  canopy  '  ]  i n t o i t s d i r e c t and d i f f u s e  (11) assumes t h a t  roof  )  to the s o l a r  and i n t e r c e p t e d  t h e above a n a l y s i s .  that  [  follows:  x,  r,j  [(1-F  in  w,i>  t h e s o l a r r a d i a t i o n i n c i d e n t on e a c h  " j " of the roof  r,D  roof  D  Then, t h e s o l a r r a d i a t i o n t r a n s m i t t e d  calculated I  +  o f the gable roof  i s divided  components.  is  w,i  t o t h e g r e e n h o u s e may be e s t i m a t e d  manner. of  ( B  s o l a r r a d i a t i o n o r i g i n a t i n g from the  from e q u a t i o n  by t h e p l a n t  (11) t h r o u g h a s i m p l e  to give, 2  I' r  =  ^ B . x, . A . + D . T, . A . [(1-F ) Z-/ r,j b,D r,3 r,j &,i r,j r-*r j=l  + F  r-»-r  (1-T, -*-a.J F d,]*  j*  r+p  * D e r i v a t i o n o f t h e d i f f u s e component i s g i v e n i n A p p e n d i x K.  ]  (12)  of equation  (11)  The  radiation  configuration  factors  F  and F r->r  equations  (11) and (12) c a n be c a l c u l a t e d  described  i n S e c t i o n B o f C h a p t e r 2.  The  calculation  covering materials described The the on  solar  properties  I  reflection  Equation  r  (13) i s v a l i d  absorptance  the  to solar  C  T  from  total  = 1 + 1 w  solar  r  d f r  Again,  then the s o l a r  i f only energy  -a ) 1 r  (13)  when t h e two s l o p e s o f t h e g a b l e  roof  f o r t h e t r a n s m i t t a n c e and  radiation. e n e r g y c a p t u r e d by t h e g r e e n h o u s e i s radiation  o f the greenhouse.  Q _ SOL  originating  c a n o p y may be e s t i m a t e d by  t h e same v a l u e s  sum o f t h e s o l a r  roof  i s considered  ( 1 - s ) [1 + ? d - r  have a p p r o x i m a t e l y  The  radiation i s  c a n o p y and t h e r a d i a t i o n  by t h e t o p o f t h e p l a n t  = I'  r  radiation  o f the roof-covering m a t e r i a l .  first  captured  solar  s l o p e s a n d c a p t u r e d by t h e g r e e n h o u s e i s d e p e n d e n t  the albedo o f the plant  the  t h e method  i n A p p e n d i x A.  amount o f t o t a l  roof  using  o f t h e t r a n s m i t t a n c e o f the greenhouse  f o r beam and d i f f u s e  i n detail  in r+p  from the v e r t i c a l  w a l l s and  Thus, (14)  SECTION B  C A S E STUDY I I  HEATING REQUIREMENTS OF A C O N V E N T I O N A L G A B L E GLASSHOUSE  DESCRIPTION AND The this  computer  simulation  c h a p t e r was used  transmission heat by  ASSUMPTIONS  loss  heat  to p r e d i c t  loss  from  Then,  as w e l l  as the f r a c t i o n  through  natural  calculated  solar  energy The  respect i)  solar  and  o f the t o t a l  radiation  heat  energy  heat load  captured  requirement supplied  c a p t u r e by t h e h o u r l y heat  greenhouse l o s s and  inputs. additional  assumptions  t h e minimum g r e e n h o u s e assumed  simulation objective  (This  a r e made  case  assumption  is specified  the time  i s adequate  of the i f the main  i s the d e t e r m i n a t i o n of h e a t i n g  Infiltration  iii)  The a l b e d o  rate  i s assumed  of the p l a n t  and assumed  gable greenhouse  100m and a w i d t h  used  o f 10m.  loads).  t o be c o n s t a n t .  canopy w i t h i n  equal  with  study.  temperature  constant throughout  ii)  The  the supplemental  to the c o n v e n t i o n a l greenhouse  constant  envelope, the  and t h e s o l a r  u s i n g the p r e d i c t e d  following  Only  i n Section A of  h o u r l y v a l u e s o f the  the greenhouse  due t o i n f i l t r a t i o n ,  the greenhouse.  were  model d e v e l o p e d  the greenhouse  is  to ten percent.  i n the case  s t u d y has a l e n g t h o f  The l o n g a x i s  o f the g r e e n h o u s e  is  east-west  oriented.  greenhouse ground.  The f o o t i n g  are i n s u l a t e d  The g r e e n h o u s e  glass.  to minimize heat i s covered  Other p e r t i n e n t  o f the c o n s t r u c t i o n  greenhouse  management  RESULTS AND  gable  and  computer  greenhouse G  daily  year.  transmission  the  heat  energy  loss  collection  of Appendix  heat  that  for a  conventional  i s included i n  tables  give  the  captured heat  i s supplied  in  (i.e.night  i n the t a b l e s  include  by t h e g r e e n h o u s e ,  losses  requirement  hourly  of the  described  temperature  The i n f o r m a t i o n  and i n f i l t r a t i o n  supplemental  output  day o f each month  a t a minimum  predicted  4.2.  To  4.1.  t o the g r e e n h o u s e  solar radiation passively  results  4.1.  a cross-sectional  i n Figure  These  results for a typical  t e m p e r a t u r e ) o f 15°C.  solar  as the  in Table  i n V a n c o u v e r , B.C.  ( T a b l e s G.l t o G.12).  The r e s u l t s a p p l y  total  l a y e r of  as w e l l  are given  simulation  located  T a b l e 4 J. and o p e r a t e d  the  to the  DISCUSSION  sample  Appendix  o f the  parameters, the  the d e s c r i p t i o n o f t h e f a c i l i t y i s shown  loss  a single  materials  parameters  view o f t h e g r e e n h o u s e  A  with  construction  properties  complete  and the p e r i m e t e r  as w e l l  as the  and t h e f r a c t i o n o f  by s o l a r due t o n a t u r a l  by t h e g r e e n h o u s e .  G i s shown, on a m o n t h l y  A summary basis,  of the  i n Table  (0,1 h a ) INSULATED PERIMETER'  i ^_ FIGURE 4.1:  10 m  J  V  3  CROSS-SECTION OF THE CONVENTIONAL GABLE GREENHOUSE USED IN CASE STUDY I I .  -J  VARIABLES USED TO CALCULATE HEATING DEMANDS OF Construction  A CONVENTIONAL GABLE GREENHOUSE Parameters  Length: Width: Height: Roof S l o p e : Orientation: Construction  Materials  Surface  South Roof N o r t h Roof South Wall North Wall East Wall West W a l l Footing Perimeter  Glass  100 m 10 m 2 m 18° East-West Long  Axis  Properties  Material  Single Glass Single Glass Single Glass Single Glass Single Glass Single Glass Insulated Concrete ^Insulated  Area  U  (m2)  (Wm^K" )  526 526 200 200 28 28 110  8.83 8.83 8. 03 8.03 8.03 8.03 0.67  220 (m)  1  0, 0, 0. 0. 0. 0.  08 08 08 08 08 08  0.94 0.94 0.94 0.94 0.94 0.94  0.67 (Wm K _1  Properties Thickness: Extinction Coefficient: R e f r a c t i o n Index: Absorptivity to Solar Radiation: E m i s s i v i t y f o r Thermal R a d i a t i o n :  Management  0.3 cm 0.252 cm" 1.526 0.08 0.94  1  Parameters  Location:  Minimum G r e e n h o u s e r e m p e r a t u r e : I n f i l t r a t i o n Rate: P l a n t Canopy A l b e d o 1  V a n c o u v e r , B.C. M o n t r e a l , Quebec H a l i f a x , N.S. 10°C, 15°C, o r 20°C 1.5 A i r c h a n g e s p e r h o u r 0.1  A close  e x a m i n a t i o n o f T a b l e 4.2 r e v e a l s  points with respect  to a single  o p e r a t i o n a t a minimum i n s i d e located i)  i n the Vancouver,  The h e a t i n g the y e a r .  This  The n a t u r a l greenhouse the  gable  t e m p e r a t u r e o f 15°C and  B.C. a r e a ,  i s due t o c o o l  summer n i g h t s  contribution heating  of solar  radiation  t o 37 p e r c e n t i n t h e  The a n n u a l a v e r a g e  28 p e r c e n t e v e n  though  requirement. solar of  energy  1.5.  storage could  to the  l o a d c a n be a s low a s 15 p e r c e n t i n  summer months and i n c r e a s i n g  t h e greenhouse  which  o f the region,  spring period.  by  greenhouse  s e a s o n e x t e n d s o v e r t h e t w e l v e months o f  are c h a r a c t e r i s t i c ii)  glazed  the following  i s f o u n d t o be o n l y  the annual s o l a r  energy c a p t u r e d  well  exceeds  the annual heating  For this  typical  case, the r a t i o  input  Therefore,  t o annual heat l o s s i f an a d e q u a t e  i s incorporated;  be h e a t e d s o l e l y  load  o f annual  i s i n the order  seasonal thermal  theoretically,  by t h e n a t u r a l  the greenhouse  solar  energy  capture o f the greenhouse. F u r t h e r c o m p u t e r a n a l y s e s were p e r f o r m e d on an i d e n t i c a l greenhouse of  to that  the a d d i t i o n a l  climatic  used  i n the Vancouver  case.  analyses i s to investigate  c o n d i t i o n s on t h e g r e e n h o u s e  The p u r p o s e  the e f f e c t o f  performance.  MONTHLY AVERAGE HEATING LOAD, SOLAR ENERGY INPUT, SOLAR CONTRIBUTION AND SUPPLEMENTAL HEAT REQUIREMENTS 2 IN MJ PER m  OF GREENHOUSE  FLOOR AREA AND PERCENT  OF THE HEATING LOAD SUPPLIED BY SOLAR FOR THE CONVENTIONAL GABLE GREENHOUSE  OF CASE STUDY I I  (MINIMUM INSIDE TEMPERATURE = 15°C) VANCOUVER,  Month  Heat Loss  Solar Input  B.C.  Solar Contribution  Supplemental Heat  Percent Solar  January  462  187  112  350  24  February  365  225  106  259  29  March  383  360  130  253  34  April  262  394  97  165  37  May  15 3  465  53  100  35  June  77  528  24  53  31  July  43  512  10  33  21  August  32  487  6  26  17  September  80  372  13  67  15  October  232  276  66  166  28  November  340  160  84  256  25  December  449  138  101  348  22  Year  2878  4104  802  2076  28  Summaries  of  Canada a r e Halifax,  the  results  included  N.S.  Vancouver;  however,  t h r e e months s h o r t e r .  i t can  Vancouver or H a l i f a x  heating the  the  load  value of  T h i s may  solar  is slightly  28  in  former  cities  effect  of  increased solar  higher  greenhouse  when compared requirements were f o u n d  radiation  i n megajoules 2076, 2718  a t a minimum  Vancouver,  (  the  and  to  contribution and  to  i n p u t was  The per and  annual  square  cancelled  and  Montreal  located  i n the V a n c o u v e r  and  metre o f  than even  is higher the  by  the  Montreal  supplemental  o f 15°C  Halifax  the  Obviously,  3262 f o r a  temperature  to  f o r Vancouver  later.  is  Montreal  i n p u t t o the g r e e n h o u s e i n the  that  the  interesting  for Halifax  floor  heat area  greenhouse and  respectively. area w i l l  of  t o the warmer  compared  found  to  for Montreal  attributed  energy  those  extent  is similar  heating loads for Halifax  operated  greenhouse  than  to Vancouver.  t o be  that  It is also  percent previously  solar  seen  r e g i o n as  lower  the  the  be  regions.  annual  be  the h e a t i n g s e a s o n  though the  in  f o r M o n t r e a l , P.Q.  in Halifax  summer n i g h t s i n the M o n t r e a l  that  locations  i n T a b l e s 4.3 and 4.4 a r e compared t o  T a b l e 4.2 f o r V a n c o u v e r ,  notice  additional  respectively.  the g r e e n h o u s e h e a t i n g s e a s o n for  two  i n T a b l e s 4.3 and 4.4  When the v a l u e s in  f o r the  located  in  Thus, a require  31  MONTHLY AVERAGE HEATING LOAD, SOLAR ENERGY INPUT, SOLAR CONTRIBUTION AND SUPPLEMENTAL HEAT REQUIREMENTS 2 IN MJ PER m  OF GREENHOUSE  FLOOR AREA AND PERCENT  OF THE HEATING LOAD SUPPLIED BY SOLAR FOR THE CONVENTIONAL GABLE GREENHOUSE  OF CASE STUDY I I  (MINIMUM INSIDE TEMPERATURE = 15°C) MONTREAL,  Month  Heat Loss  Solar Input  QUEBEC  Solar Contribution  Supplemental Heat  Percent Solar  January  908  170  170  738  19  February  750  218  191  559  26  March  609  367  200  409  33  April  340  392  125  215  37  85  465  17  68  20  June  4  525  0  4  0  July  0  510  0  0  0  August  0  485  0  0  0  47  370  5  42  11  October  257  270  67  190  26  November  465  150  115  350  25  December  810  123  123  687  15  4275  4045  1013  3262  24  May  September  Year  MONTHLY AVERAGE HEATING LOAD, SOLAR ENERGY INPUT, SOLAR CONTRIBUTION AND  SUPPLEMENTAL HEAT  REQUIREMENTS  2 IN MJ PER m  OF GREENHOUSE  FLOOR AREA AND  PERCENT  OF THE HEATING LOAD SUPPLIED BY SOLAR FOR THE CONVENTIONAL GABLE GREENHOUSE (MINIMUM  OF CASE STUDY I I  INSIDE TEMPERATURE = 15 °C) HALIFAX, N.S.  Month  Heat Loss  January  Solar Input  Solar Contribution  Supplemental Heat  640  167  143  497  22  February  586  217  158  428  27  March  533  356  176  357  33  April  366  392  134  232  37  May  216  464  75  141  35  June  93  525  24  69  26  July  31  509  4  27  13  August  25  485  4  21  13  September  70  370  9  61  13  October  209  269  49  160  23  November  357  149  85  272  24  December  567  121  114  453  20  3693  4024  975  2718  26  Year  Percent Solar  percent  and  greenhouses  57  percent  located  Furthermore, captured  by  compared,  energy  in Halifax  i t i s found  These  ratios  are  long  thermal  s t o r a g e s are  A new  Vancouver  area  than  1.09  a r e a of r e s e a r c h f o r energy  of greenhouse  simulation  model was  minimum g r e e n h o u s e requirement passive  and  solar.  parameters  as  analysis.  For  assumed  t o be  crops. used  fraction The  here,  of  the p u r p o s e located  this  f o r minimum g r e e n h o u s e  and  Summaries  to  4.6.  of  low  these  areas.  temperature  computer the  area.  supplied the  of  by  construction in  this  the g r e e n h o u s e i s Analyses  temperatures  a n a l y s e s are  effect  heat  a g a i n used  study,  i n the H a l i f a x  performed 20°.  of  greenhouse with  of  adaptable  conservation in  supplemental  in Table 4.lis  the  Therefore,  to i n v e s t i g a t e on  are  for  or M o n t r e a l  the h e a t i n g l o a d  typical  specified  1.42  T h e r e f o r e , the  temperature  losses  t o be more  the H a l i f a x  radiation  area holds  and  g r e e n h o u s e p r o d u c t i o n i s the d e v e l o p m e n t hybrids  solar  respectively. likely  to  respectively.  heat  Vancouver  0.95,  and  the V a n c o u v e r  Montreal of annual  that  Halifax  to  when compared  t o the a n n u a l  Montreal, term  and  when the r a t i o s  the g r e e n h o u s e  again,  advantage.  less  were  o f 10°C,  15°C  shown i n T a b l e s  4.4  MONTHLY AVERAGE HEATING LOAD, SOLAR ENERGY INPUT, SOLAR CONTRIBUTION AND SUPPLEMENTAL HEAT REQUIREMENTS IN MJ PER m  2  OF GREENHOUSE  FLOOR AREA AND PERCENT  OF THE HEATING LOAD SUPPLIED BY SOLAR FOR THE CONVENTIONAL GABLE GREENHOUSE  OF CASE STUDY I I  (MINIMUM INSIDE TEMPERATURE = 10°C)  HALIFAX, N.S.  Supplemental Heat  Percent Solar  Solar Input  Solar Contribution  482  167  112  370  23  February  444  217  123  321  28  March  377  356  123  254  33  April  215  392  69  146  32  May  87  464  18  69  21  June  19  525  2  17  14  -  -  Month  Heat Loss  January  July August September  -  509 485 370  -  75  269  7  68  9  November  206  149  44  162  21  December  409  121  87  322  21  2321  4024  585  1736  25  October  Year  MONTHLY AVERAGE HEATING LOAD, SOLAR ENERGY INPUT, SOLAR CONTRIBUTION AND  SUPPLEMENTAL HEAT  REQUIREMENTS  2 IN MJ PER m OF  OF GREENHOUSE  FLOOR AREA AND PERCENT  THE HEATING LOAD SUPPLIED BY SOLAR FOR THE  CONVENTIONAL GABLE GREENHOUSE (MINIMUM  OF CASE STUDY I I  I N S I D E TEMPERATURE = 2 0 ° C ) HALIFAX, N.S.  Heat Loss  Solar Input  January  796  167  164  632  20  February  729  217  189  540  26  March  689  356  225  464  33  April  518  392  193  325  37  May  370  464  148  222  40  June  220  525  85  135  39  July  115  509  28  87  25  August  107  485  23  84  21  September  192  370  52  140  27  October  363  269  102  261  28  November  507  149  120  387  24  December  725  121  121  603  17  5331  4024  1451  3880  27  Month  Year  Solar Contribution  Supplemental Heat  Percent Solar  Table  4.7 g i v e s t h e p r e d i c t e d m o n t h l y  heat requirements temperatures due  f o r the selected  as w e l l  as t h e e x p e c t e d p o t e n t i a l  t o 15°C and t o 10°C r e s p e c t i v e l y .  from  20°C t o 15°C i s a b o u t  temperature.  The a n n u a l  from  20°C  potential temperature  An a d d i t i o n a l i s further  25 p e r c e n t decreased  reduction i n  O b v i o u s l y , t h e above a p p r o x i m a t i o n i s o n l y  contribution  greenhouse  of solar  i s not s i g n i f i c a n t l y  temperature  o p e r a t i o n as c a n c l e a r l y  radiation  affected  as c a n be d e p i c t e d  the greenhouse  by l o w e r i n g t h e  i n T a b l e s 4.4  indoor temperature  fraction  t o the annual h e a t i n g  tends  of the heating load  when t h e e n t i r e  Reducing  to increase the  supplied  o t h e r months o f t h e y e a r , t h u s r e s u l t i n g effect  greenhouse  t o 4.6.  by s o l a r d u r i n g  t h e w i n t e r months b u t i t h a s an o p p o s i t e e f f e c t  overall  savings  i n T a b l e 4.7.  The  monthly  30 p e r c e n t .  5 p e r c e n t s a v i n g p e r degree  f o r a l l year around  seen  load  energy  temperature  i f t h e minimum t e m p e r a t u r e  t o 10°C o r a r o u n d  valid  greenhouse  s a v i n g due t o r e d u c i n g t h e minimum g r e e n h o u s e  c a n be e x p e c t e d  be  t h r e e minimum  t o r e d u c i n g t h e minimum g r e e n h o u s e  energy  supplemental  during the  i n a negligible  year i s considered (Tables  4.4 t o 4 . 6 ) . As of  expected,  the greenhouse  radiation this  ratio  l o w e r i n g o f t h e minimum i n s i d e increased  capture t o heat  significantly  loss.  on an a n n u a l b a s i s ,  temperature  the r a t i o o f s o l a r  From T a b l e s 4.4 t o 4.6, c a n be c a l c u a t e d  a s 0.75, 1.09  TABLE EFFECT  4.7  OF MINIMUM INSIDE GREENHOUSE TEMPERATURE  ON SUPPLEMENTAL HEAT REQUIREMENT AND EXPECTED ENERGY SAVINGS DUE TO REDUCING THE MINIMUM TEMPERATURE FROM  20°C  HALIFAX, N.S. Supple. Heat* T =20°C 2  Supple. Heat* T =15°C 9  January  632  497  21  370  41  February  540  428  21  321  41  March  464  357  23  254  45  April  325  232  29  146  55  May  222  141  36  69  69  June  135  69  49  17  87  July  87  27  69  August  84  21  75  September  140  61  56  7  95  October  261  160  39  68  74  November  387  272  30  162  58  December  603  4 53  25  322  47  30  1736  55  Month  Year  3880  S  ^ Percent 9S a  2718  v  i  n  T  Supple. x^t* Percent o Savings g =  1  0  c  -  100 100  2 In  MJ p e r m  greenhouse f l o o r  a r e a p e r month  and  1.73  10°C  f o r minimum i n s i d e  temperatures  of  reducing cover  infiltration/exfiltration  over  retrofit  a glasshouse).  to minimize  energy The  is utilized  savings  due  A  4.8.  The  greenhouse are are  Table  single  4.8  an  annual  be  from  of  i n Section A of  the p o t e n t i a l  the  and  operated  specification 4.1.  The  4.8  are gross t o be  that with  glasshouses,  The  i s included gable a t a minimum f o r the  weather  heat  percent energy  values;  relatively  data  loss  savings  i n energy  in  as  therefore,  smaller.  infiltration  due  resulting  Thus,  t h e e x c e p t i o n o f o l d and  reducing  factor  the  region.  between 7 t o 13 percent.  this  annual  into  f o r an e a s t - w e s t  of the H a l i f a x  12  Table  a significant  greenhouse.  are  20°C, o t h e r  ranged  concluded  maintained t o be  any  d e p e n d s on  simulation results  glass cover  savings are expected can  loss  shows t h a t t h e m o n t h l y a v e r a g e  average  calculated  of  typical  infiltration  it  (i.e. plastic  of a i r i n f i l t r a t i o n  included i n Table  to  net  to p r e d i c t  results  temperature  here  here  summary o f t h e  greenhouse w i t h  used  heat  model d e v e l o p e d  to e l i m i n a t i o n  greenhouse.  inside  losses  However, t h e e c o n o m i c s o f  infiltration  mathematical  Table  i n greenhouses i s  savings.  chapter  in  and  respectively. A n o t h e r method o f c o n s e r v i n g e n e r g y  net  20°C, 15°C  i s not  conservation for  badly  considered  EFFECT OF INFILTRATION  KEPT AT A MINIMUM  RATE ON  SITPPT.PMPM-PKT  INSIDE TEMPERATURE OF 20°C HALIFAX,  N.S.  Supplemental Heat (MJ/m F l o o r A r e a p e r Month) 2  1.5 A i r C h a n g e s P e r Hour  Zero Infiltration  January  632  552  13  February  540  473  12  March  464  407  12  April  325  286  12  May  222  197  11  June  135  121  10  July  87  79  9  August  84  78  7  September  140  127  9  October  261  233  11  November  387  343  11  December  603  524  13  3880  3420  12  Month  Year  Percent Due t o Infiltration  Conventional heating  systems.  fraction sun  greenhouses  of  the  Their  percent.  The  greenhouse energy  energy  solar  active  storage.  collection  1978  an  and  The  and  1979).  energy  radiation  energy  solar  radiation  monthly  by  can  average  solar  be  of  i n F i g u r e 4.2.  average  fractions  supplied identical in  by  solar  of  (to  are  greenhouses  Montreal.  by  solar  determined  using  the  the  as  heating By  the  unity  is available utilization single  sake of  located  The  the  ratio to  of  the  definition, implies is  for  the  solar a  that  all  utilized, storage.  factor  for  layer  of  comparison  greenhouse h e a t i n g shown.  solar  Abdallah,  load)  greenhouse  also  the  energy  by  the  for  (Ben  by  25  solar  of  For  of  making  providing  is defined  a  is supplied  order  factor  energy  one  i n the  greenhouse.  energy  the  that  as  active  west g a b l e greenhouse c o v e r e d w i t h plotted  load  improved and  solar  when e x p r e s s e d  (S.E.U.) c o n c e p t  the  captured  excess  be  factor  utilization  no  be  system  contribution  solar  therefore,  can  factor This  captured  to  potential  storage  utilization  heating  found  efficiency  as  b a s i c a l l y passive  efficiencies  greenhouse  were p r e v i o u s l y  are  load  The  an  east-  glass  the  are  monthly  that  results  are  for  i n Vancouver  and  the  is two other  the  MONTH  FIGURE 4.2:  MONTHLY AVERAGE SOLAR ENERGY  UTILIZATION  FACTOR AND FRACTION OF HEATING LOAD SUPPLIED BY PASSIVE SOLAR FOR AN E-W GREENHOUSE  GABLE  (SINGLE GLASS COVER, MINIMUM  INSIDE TEMPERATURE  15°C).  The can  be  information presented  interpreted  January, the  as  i t i s seen  solar  i n the graph  follows:  captured  4.2  f o r e x a m p l e , t h e month o f  t h a t , f o r Vancouver,  radiation  of Figure  by  60  percent  of  the greenhouse i s p a s s i v e l y  utilized  to supply  24  percent  o f the h e a t i n g l o a d w h i l e  the case  of Montreal,  a l l the  s o l a r energy  is utilized  s u p p l y o n l y 19 p e r c e n t o f t h e g r e e n h o u s e h e a t i n g For Montreal is  zero  of  solar  the  i s zero, thus,  energy  from  o f the h e a t i n g  F i g u r e 4.2  captured percent  be  percent  energy  environmental of solar  location  utilization  f o r Vancouver 1 to 5  is utilized  to supply  17  factor percent  to  31  contribute significantly  s p r i n g and  f o r example, 32  energy  fall.  in April,  As  can  25 p e r c e n t  f o r Montreal  of the  the greenhouse are u t i l i z e d  solar  availability to  solar  s t o r a g e may  o f the h e a t i n g  The the  and  by  load.  load.  s a v i n g s d u r i n g the  Vancouver,  to  the  captured  S o l a r energy energy  to  summer m o n t h s , t h e g r e e n h o u s e h e a t i n g l o a d i n  for that period, while  percent  in  be  seen  for  solar  to supply  to  energy  37  load. utilization  temperature  factor and  to  is closely the  r a d i a t i o n . Therefore, i t i s  dependent.  The  effect  related  of l o c a t i o n  expected on  the  CD  \—  >-  i  o  M  A  M  J  J  A  S  O  N  D  MONTH FIGURE 4.3:  EFFECT OF LOCATION ON THE SOLAR ENERGY UTILIZATION FACTOR FOR AN E-W  (S.E.U.)  GABLE GREENHOUSE  BY MONTH (SINGLE GLASS  COVER, MINIMUM INSIDE TEMPERATURE OF  15°C).  solar The  energy  figure  analysed, solar  indicates Vancouver  energy  storage.  values  factor  that  i s depicted  among t h e t h r e e  i s more s u i t a b l e  utilization  Also  utilization  i n Figure locations  f o r improvement  by t h e i n c o r p o r a t i o n  shown on F i g u r e 4.3, the a n n u a l  factors  f o r the three  4.3.  locations  of a  thermal  solar which  t o the  energy have t h e  o f 0.20, 0.24 and 0.25 f o r V a n c o u v e r , H a l i f a x and  Montreal of  utilization  respectively.  the h e a t i n g  loads  The c o r r e s p o n d i n g  which  are s u p p l i e d  annual  fractions  by s o l a r  a r e 0.28,  0. 26 and 0.24 f o r V a n c o u v e r , H a l i f a x  and M o n t r e a l  respectively.  solar  utilization storages  Obviously,  factors  the a n n u a l  are of value  only  energy  when l o n g - t e r m  thermal  are a n t i c i p a t e d .  CONCLUSIONS The of  following  the s i m u l a t i o n  utilization in 1.  this  conclusions of h e a t i n g  can be drawn requirements  of the c o n v e n t i o n a l  gable  from  the r e s u l t s  and s o l a r  greenhouse  energy  described  section:  The a n n u a l heating  solar  load  percentage  energy  was found  i s found  contribution t o be about  t o be o n l y  t o the g r e e n h o u s e  25 p e r c e n t .  slightly  affected  This  by 2.  location  and minimum g r e e n h o u s e  The r a t i o o f s o l a r to  radiation  the annual h e a t i n g  load  0.75 t o 1.75 d e p e n d i n g and  i t s minimum  temperature  c a p t u r e by t h e g r e e n h o u s e  was  found  t o be i n t h e r a n g e o f  on t h e l o c a t i o n  temperature  setting.  setting.  o f the g r e e n h o u s e Therefore,  theoretically  a greenhouse  with a seasonal thermal  storage  be made s e l f  s u f f i c i e n t i n energy  could  f o r most  cases. 3.  Lowering in  s i g n i f i c a n t energy  saving could 4.  f o r each  savings.  degree  For a well  constructed  minimizing  infiltration  ten  i n energy  The s o l a r  energy  significantly storing  factor  Kelvin  temperature  results  A f i v e percent energy reduction  i n temperature  increase from  greenhouses.  was f o u n d  greenhouse,  t o be an i n s i g n i f i c a n t  Net s a v i n g s o f l e s s  than  be e x p e c t e d . utilization  during  daytime  and m a i n t a i n e d  conservation.  percent could  would  minimum  be e x p e c t e d .  factor  5.  o f the g r e e n h o u s e  factor  the s p r i n g  e x c e s s heat  could  and f a l l  be  improved  p e r i o d s by  f o r n i g h t t i m e use.  the annual s o l a r  energy  i t s low v a l u e o f a b o u t  This  utilization  0.20 f o r c o n v e n t i o n a l  NOMENCLATURE  Symbol  De f i n i t i o n  Units  Surface  area  o f the foundation  Surface  area  o f any v e r t i c a l  A  Surface  area  sloped  B  Beam s o l a r r a d i a t i o n i n c i d e n t on s l o p e d  A  f  A. l  2  m  wall  "i"  m  roof " j "  m k J . h -"-.m  2  roof " j " B  v, Y  Beam s o l a r r a d i a t i o n i n c i d e n t on a  w, 1  Beam s o l a r r a d i a t i o n t r a n s m i t t e d any  C  P  .m  wall of orientation y  vertical B  kJ.h  vertical  Specific  wall  through  kJ.h  -1  "i"  heat o f a i r a t constant  kJ.ka .K~ "a 1  1  pressure Diffuse sloped  s o l a r r a d i a t i o n i n c i d e n t on  s o l a r r a d i a t i o n i n c i d e n t on a  vertical w,i  Diffuse  wall  F  r->-r  F m  roof  two s l o p e s  passive  Average  -1 kJ.h"  "i"  canopy  o f t h e greenhouse fraction  roof  of the  load  supplied  heat  transfer  solar  convective  coefficient of  .m  c o n f i g u r a t i o n f a c t o r between  greenhouse h e a t i n g  h. . i, i  wall  and t h e p l a n t  Monthly average  by  2  c o n f i g u r a t i o n f a c t o r between  Radiation the  kJ.h  solar radiation transmitted  Radiation the  .m  of orientation y  t h r o u g h any v e r t i c a l F  -1  roof " j "  Diffuse  D  kJ.h  f o r the inside  the greenhouse  cover  surface  . .-1 -2 -1 kJ.h .m .K T  I  Total  solar r a d i a t i o n transmitted  through the r o o f t h a t the I' r  plant  Total  i s captured  1  kJ.h" by  canopy  solar r a d i a t i o n transmitted  kJ.h  -1  t h r o u g h t h e g r e e n h o u s e r o o f and intercepted Total  by t h e p l a n t  solar r a d i a t i o n transmitted  through  roof  intercepted w  Total  slope  by t h e p l a n t  w,i  a P  1  kJ.h"  1  by t h e  Total  solar r a d i a t i o n transmitted  captured N  i s captured  canopy  "i"  kJ.h"  walls of the  plant  wall  1  canopy  s o l a r r a d i a t i o n transmitted  greenhouse t h a t  kJ.h"  " j " that i s  through the v e r t i c a l  I  canopy  through  o f t h e greenhouse t h a t i s by t h e p l a n t  canopy  Greenhouse  infiltration  Greenhouse  perimeter  Q  INF  Heat  l o s s due t o  Q  SOL  Solar energy i n p u t  Q  SUP  rate  ( a i r changes)  1  h m  infiltration  kJ.h  t o t h e greenhouse  Supplemental heat requirement f o r the  -1  kJ.h kJ.h"  1  greenhouse TRAN  Heat  loss or gain  through the greenhouse  kJ.h  -1  envelope Thermal r e s i t a n c e o f t h e greenhouse c o v e r for  any s u r f a c e  s u r f a c e wind  "i"  excluding  coefficient  the outside  h.m .K.kJ 2  - 1  R  2 c ,  Thermal S.E.U,  resistance  cover material  o f the greenhouse  o f any s u r f a c e  Monthly average s o l a r utilization Inside  S,l  energy  greenhouse temperature  K  Outside  s u r f a c e t e m p e r a t u r e o f any  K  "i"  Heat t r a n s f e r  film  "i"  coefficient of  c o e f f i c i e n t o f any  excluding  heat t r a n s f e r  coefficient  Wind  b,j  km. h  d,i  T  d,j  solar  t o beam s o l a r -  solar  slope  " j " t o beam  radiation "i"  to diffuse  radiation  Transmittance of roof diffuse  a1•  "i"  radiation  Transmittance of wall T  m  speed  Transmittance of roof T  kJ. h ^ . m  the perimeter  Transmittance of wall b,i  , -1 -2 -1 kJ.h .m .K  the outside  Volume o f t h e g r e e n h o u s e  T  -1 -2 -1 k J . h .m K  coefficient  Effective for  w  K  environmental temperature  surface  u  "i"  factor  O v e r a l l heat t r a n s f e r the f o u n d a t i o n i  h.m .K.kJ  Outside  wall  U  —1  1  solar  Absorptance  slope  " j " to  radiation  of wall  "i"  to solar  radiation Absorptance o f the greenhouse roof t o solar  radiation  -1  .K ^  Orientation  o f t h e s u r f a c e f r o m due  radians  south -3 Density of a i r Albedo o f the p l a n t  Kg.m canopy  CHAPTER 5  COMPUTER S I M U L A T I O N MODEL OF ENERGY REQUIREMENTS FOR A COMBINED G R E E N H O U S E - L I V E S T O C K BUILDING  INTRODUCTION The  mathematical  analysis that  model d e v e l o p e d  of v e n t i l a t i o n requirements  developed  i n Chapter  c o n v e n t i o n a l greenhouses determine by  the p o t e n t i a l  section,  4 to predict a r e combined  energy  chapter consists  s h e l t e r s , and  the heating loads of i n t h i s chapter to  s a v i n g s w h i c h c o u l d be r e a l i z e d  from The  o f two s e c t i o n s .  t h e combined m o d e l i s d e s c r i b e d ;  discussion  on t h e e f f e c t s o f p o l l u t a n t s  the animal second  s h e l t e r on p l a n t  section  i s devoted  analysis  of a t y p i c a l r e t r o f i t  hog  combination.  barn  the c o n t r i b u t i o n heating by  of animal  3 f o r the  a combined g r e e n h o u s e - l i v e s t o c k b u i l d i n g o p e r a t i o n . The  air  i n Chapter  also  present i n the exhaust  t o a computer  case o f a gable  In t h i s case  a brief  growth i s p r e s e n t e d . simulation  glasshouse-  s t u d y , e m p h a s i s was on  o f a n i m a l waste heat  requirements.  In the f i r s t  r e c o v e r y t o the greenhouse  F i n a l l y , a comparison  o f h e a t demands  a f r e e - s t a n d i n g and an a t t a c h e d g r e e n h o u s e i s a l s o  given.  SECTION A  M A T H E M A T I C A L MODEL DEVELOPMENT OF GREENHOUSE-LIVESTOCK COMBINATION  MODEL DEVELOPMENT  ASSUMPTIONS All  the assumptions  livestock during  model d e v e l o p m e n t  the development  mathematical  model  assumptions  to the  3 and t h o s e made  of the c o n v e n t i o n a l greenhouse  case.  4 a p p l y t o the  In a d d i t i o n ,  combined  the f o l l o w i n g  were c o n s i d e r e d :  The v e n t i l a t i o n of  with respect  i n Chapter  i n Chapter  greenhouse-livestock  i)  stated  a i r f o r temperature  the l i v e s t o c k  building  or moisture  control  i s t a k e n as 100 p e r c e n t  outside a i r . ii)  The v e n t i l a t i o n exhausted lost  iii)  directly  The w a l l  separating  heat  relatively  small  between  compared  building  building i s t o be u l t i m a t e l y  the g r e e n h o u s e  the l i v e s t o c k  transfer  the sensible  energy  the greenhouse  through  the b u i l d i n g s  livestock  the l i v e s t o c k  i s assumed  conduction  Only  into  by e x f i l t r a t i o n  the greenhouse  iv)  a i r from  space  from  t o be a d i a b a t i c between  that o f  since  the two b u i l d i n g s i s  t o the t o t a l  and t h e i r  vents.  heat  exchange  environments.  p o r t i o n o f t h e waste h e a t from t h e i s recovered, thus the p r e d i c t e d  s a v i n g s b y t h i s model a r e c o n s e r v a t i v e .  HEAT BALANCE ABOUT THE For  the p u r p o s e  of h e a t i n g l o a d  greenhouse-livestock single  structure  The  attic  ii)  The  livestock  iii)  The  greenhouse  The  temperature, radiation  following  be  taken  three  as  a  zones:  zone  i n the a t t i c  respect  t o the  t o be  space  i s estimated  conventional livestock  ( 7 ) , (2) and  i s assumed  (3).  a function  The of  the o u t s i d e a i r t e m p e r a t u r e ,  absorbed  resistances  the  can  zone  equations  temperature  system  the  SPACE  with  3:  of  calculations,  zone  temperature  indicated Chapter  combination  composed  i)  ZONE I : A T T I C  BUILDING  of  by  the r o o f ,  the r o o f  and  the  and  the the  of  unit  attic barn solar  the r e s p e c t i v e  ceiling  as  the  thermal  livestock  building.  ZONE I I : LIVESTOCK BUILDING The building  supplemental may  determined. livestock  be The  heat  calculated  required  the  whence the a t t i c  g e n e r a l heat  zone may  by  be w r i t t e n  livestock temperature  b a l a n c e e q u a t i o n about as  follows:  the  is  in  Q  SUP,L where  Q  SENS ~ VENT  the p l u s  values  sign  ,  (1)  (+) i n d i c a t e s t h a t o n l y  the p o s i t i v e  are considered.  The  s e n s i b l e heat  ventilation heat  ~ ^TRAN  Q  loss  Chapter  released  by t h e a n i m a l , t h e  r a t e and v e n t i l a t i o n  are c a l c u l a t e d using  3 with  respect  heat  loss  t h e method  and t r a n s m i s s i o n presented  to the c o n v e n t i o n a l  in  livestock  building.  ZONE I I I : GREENHOUSE The  general  heat  balance  equation  about  the a t t a c h e d  g r e e n h o u s e may be s t a t e d as f o l l o w s : SUPPLEMENTAL HEAT + SOLAR ENERGY + HEAT RECOVERED TRANSMISSION or Q  SUP,G  where  SOL  Q  Chapter  form:  H R L ~ TRAN Q  sign  ,  (  (+) i n d i c a t e s t h a t o n l y  2  )  the p o s i t i v e  are considered.  The  air  Q  the p l u s  values  loss  +  BUILDING - HEAT  = 0,  i n equation =  FROM LIVESTOCK  INPUT  above e q u a t i o n 4  term  with  i s similar  the e x c e p t i o n  i s replaced  of the l i v e s t o c k  that  by the heat zone.  to equation  (1) of  the i n f i l t r a t i o n recovery  from  heat  ventilation  The  transmission  envelope  i s calculated  developed  earlier  conventional The using  using  through  the greenhouse  t h e same method which 4  with  respect  was  t o the  greenhouse.  energy  input  t h e same m e t h o d o l o g y  determine  loss  i n Chapter  gable  solar  heat  the s o l a r  to the greenhouse developed  radiation  i s estimated  i n Chapter  captured  4 , to  by c o n v e n t i o n a l  gable  greenhouse. The a  only  combined  determine used  additional  livestock-greenhouse the h e a t  to p a r t i a l l y  greenhouse. portion then  subroutine  input supply  Since,  system  the heating  heat  building  available  f o r the case of  i s an a l g o r i t h m t o  the l i v e s t o c k  i t i s assumed  of the l i v e s t o c k  the s e n s i b l e  from  required  load  building  that i s  of the  that  only  heat  i s t o be r e c o v e r e d ,  may  the s e n s i b l e  be c a l c u l a t e d  as  follows:  Q  HRL  The  =  •™ p  above  sensible  C  " V  b  equation heat  ventilation the  ( T  (3)  clearly  is directly  rate  temperature  building  •  in unit  shows t h a t  the a v a i l a b i l i t y of  proportional  t o the l i v e s t o c k  mass o f a i r p e r u n i t  difference  between  and o f the g r e e n h o u s e .  that  time  and t o  of the l i v e s t o c k  In to  calculating  the greenhouse  from  the c o n t r i b u t i o n  heating load,  the l i v e s t o c k  building  the s e n s i b l e  to  Thus,  i n most  the greenhouse  because  passive  required  c a s e s , the c o n t r i b u t i o n  heating load  solar  heat  i s considered only  p e r i o d s when t h e a t t a c h e d g r e e n h o u s e heat.  o f the h e a t r e c o v e r e d  energy  during  time  supplemental o f waste  i s z e r o around  alone  available  noon  heat  hours,  can s u p p l y t h e t o t a l  greenhouse  h e a t demand.  ADVANTAGES  AND DISADVANTAGES OF DIRECT USE OF EXHAUST AIR  The  introduction  building well  directly  system  with  combined extra of  into  as d i s a d v a n t a g e s .  exchange used  of exhaust  the greenhouse  i s i t s low c o s t .  such  as heat  A third  enrichment in  easily  exchangers.  advantage  fans  f o r the  the a d d i t i o n o f  Another  advantage  the greenhouse,  a i r t o a minimum  i s the n a t u r a l  i n the y i e l d  exhaust  a i r is its beneficial  of o u t s i d e  of the greenhouse  an i n c r e a s e  without  as  of the d i r e c t  be a d a p t e d  the a i r p r e s s u r e w i t h i n  thus r e d u c i n g i n f i l t r a t i o n level.  could  use o f t h e e x h a u s t  of i n c r e a s i n g  has many a d v a n t a g e s  The e x i s t i n g  g r e e n h o u s e - l i v e s t o c k system  equipment,  the l i v e s t o c k  An o b v i o u s a d v a n t a g e  c o n v e n t i o n a l barns  the d i r e c t  effect  a i r from  environment o f the c r o p .  carbon which  dioxide could  result  Some o f t h e d i s a d v a n t a g e s o f t h e d i r e c t  a i r exchange  s y s t e m between t h e l i v e s t o c k b u i l d i n g and t h e g r e e n h o u s e are  r e l a t e d to dust  and ammonia a c c u m u l a t i o n .  Dust i n the  e x h a u s t a i r f r o m t h e l i v e s t o c k b u i l d i n g may a c c u m u l a t e on the  g r e e n h o u s e c o v e r i n g m a t e r i a l a n d on t h e l e a v e s  plants  thus p o s s i b l y causing  availability  f o r photosynthesis  energy c o l l e c t i o n . be  alleviated  the  exhaust  This  as w e l l a s f o r p a s s i v e  problem o f dust  by i n s t a l l i n g  when p r e s e n t  s e r i o u s problem with  airfilters  i n high  respect  damage t o t h e p l a n t s .  A very  has  been done on t h e e f f e c t s  few  species  too  little  accumulation  to undesirable limited  (EPA) r e p o r t  pH i n c r e a s e s  chronic  injury  one  hour t o i n j u r e tomato p l a n t s .  from  gas b u t  to low-level,  long-  effects.  chronic  EPA r e p o r t  other  by t h i s  Protection  internal  pigmentation  r e s p o n s e s t o NH^.  states that concentrations  gas w h i c h may be p r e s e n t  work on  (1940) t h a t  t i s s u e and c h a n g e s i n  be c o n s i d e r e d  work  Only a  (1978) and i n t h e e x p e r i m e n t a l  i n the l e a f could  o d o r and p o s s i b l y  i n a U.S. E n v i r o n m e n t a l  The  The  of  m i g h t be a  o f ammonia on p l a n t s .  i s known on p l a n t r e s p o n s e s  h a s been r e p o r t e d  the l e a f  could  amount o f r e s e a r c h  t o m a t o p l a n t s by T h o r n t o n and S e t t e r s t r o m  of  solar  a t the entrances  concentrations  has been t e s t e d f o r a c u t e  term exposure t o c o n s i d e r  Agency  i n the s o l a r r a d i a t i o n  fans.  Ammonia  It  a reduction  of the  o f 55 ppm  require  i n the exhaust a i r  l i v e s t o c k b u i l d i n g s i s hydrogen s u l f i d e .  T h o r n t o n and  Setterstrom plant  (.1940) f o u n d  tissue  as  gave t h e  Ammonia and buildings  gases.  rate of  following order  of  to  toxicity  of  > S0  2  > HCH  3  hydrogen s u l f i d e  animals,  Dalfsen  concentrations storages.  type  and  > HS  concentrations  only during  i n the  livestock  and  the  (1982) m e a s u r e d NH^  density the  HS  agitation  expected  was  2  o f manure.  were l e s s  t o be  found  a limiting  level  Certainly low  level  and  Bulley  acute  injury  toxicity  (1982) i n a n i m a l  needed t o d e t e r m i n e  concentrations  the  livestockconcentration  to p l a n t s . not  occur  r e p o r t e d by  chronic effect the  must c o n s i d e r  have shown d i f f e r e n t  for  van  at  the  Dalfsen  b u i l d i n g s . However, r e s e a r c h  o f ammonia on  A l s o , one  during  hydrogen  i t s low  to plants w i l l  o f ammonia c o n c e n t r a t i o n s  ppm  Consequently,  factor  and  of  t o 6.5  3 ppm.  systems because o f  low  2  ammonia  Even then  than  HS  i n measurable q u a n t i t i e s  greenhouse combination its relatively  and  s u b f l o o r manure  i n d i c a t e d a range of  b u i l d i n g s between 2.5  concentrations  i s not  plants  in  s y s t e m and  w i t h i n four d a i r y barns having  normal c o n d i t i o n s , w h i l e  plants.  .  2  o f manure h a n d l i n g  Bulley  Their results  concentrations  sulfide  > NH  2  ventilation.  van  is  to  With r e s p e c t  depend on many f a c t o r s i n c l u d i n g t y p e  of confined  2  other  only mildly toxic  gases: Cl  HS  was  2  compared w i t h  tomato p l a n t s , they the  that H S  of  low-level  p r o d u c t i v i t y of the  levels  of  fact  work  greenhouse  that species  t o l e r a n c e to  of  gaseous  pollution.  T h e r e a l s o may  pollutant .sensitivity (Howe and  Woltz,  intensity,  availability  may  susceptibility  considerable  between c u l t i v a r s  variation  within a  in  species  1982).  Environmental light  be  f a c t o r s s u c h as  CC^ be  temperature,  concentration, significant  water supply  i n ascerning  to gaseous p o l l u t a n t s  humidity, and  nutrient  the  plant  (Ormrod and  Blom,  1978).  SECTION B C A S E STUDY 1 1 1  ENERGY REQUIREMENTS OF A G A B L E G L A S S H O U S E - S W I N E F I N I S H I N G BARN COMBINATION  SWINE FINISHING BARN-GREENHOUSE COMBINATION  DESCRIPTION AND A  figure, this  ASSUMPTIONS  schematic of the attached  finishing  barn  configuration  from  will  roof  snow l o a d s . should of the  clear  the l i v e s t o c k greenhouse.  still  be With  be i m p r a c t i c a l  the n o r t h  Otherwise,  be l e f t  5.1. As can be seen  roof  a space  between  the two  The n o r t h  from  can accumulate wall  the e x c e p t i o n  dimensions,  the south  o f the g r e e n h o u s e  parameters  o f t h e common w a l l , such  as l e v e l  roof  damage t o should  and o p t i c a l p r o p e r t i e s  o f the g r e e n h o u s e  sizes,  minimum and maximum v e n t i l a t i o n r a t e s to those  Therefore, Chapters  used  with  the reader  such  respect  glass  as number o f hogs,  t o case  i s referred  3 and 4 f o r d e t a i l e d  other  of i n s u l a t i o n ,  and management p r a c t i c e s  of  from  structures  without  cover;  II.  other  insulated.  jconstruction  identical  removal  o r some  of the greenhouse  where snow s l i d i n g  building  where snow  f o r snow  building  i n the  obviously,  in regions  provision  o f the l i v e s t o c k  means o f p r o t e c t i n g  t o a hog  have a common w a l l ;  i s a f a c t o r without  the south  greenhouse  i s shown i n F i g u r e  t h e two b u i l d i n g s  accumulation  - A CASE STUDY  etc...are studies  to s e c t i o n  information  I and  B o f each  on b u i l d i n g  FIGURE 5.1:  CROSS-SECTIONAL VIEW OF THE GABLE GREENHOUSE-HOG (CASE STUDY  III).  BARN  COMBINATION  specifications,  o p e r a t i n g parameters  underlying  study  apply i)  case  specifically  ii)  No a t t e m p t  assumed energy  therefore only  savings  The r a t i o  o f number  This  of animals  latent  heat  of the  this  analysis;  i t i s d e p e n d e n t on t h e number o f hogs i n t h e to the design  value.  output  o f t h e computer  Appendix  H.  H . l t o H.12 show  Tables  the a t t a c h e d  year.  process.  area of  throughout  to a f i n i s h i n g  the  f o r barn  to unit  greenhouse  outdoor  removal  directly  i m p l i e s that the p r e d i c t e d  attached  the  i s drawn  DISCUSSION  A sample  between  a r e as f o l l o w s :  the s e n s i b l e p o r t i o n i s  i s assumed c o n s t a n t  a t any t i m e  RESULTS AND  study  which  are r a t h e r c o n s e r v a t i v e estimates  savings.  greenhouse  study  t h e hog b a r n  i s made i n t h i s  potential  barn  case  assumptions  f o l l o w i n g a dust  recoverable.  actually,  Additional  a i r from  the greenhouse  recovery;  iii)  to t h i s  The v e n t i l a t i o n into  III.  and a s s u m p t i o n s  greenhouse,  environment Among  hog b a r n  shown  f o r an  i s included i n  the h o u r l y  the l i v e s t o c k  fora typical  the v a l u e s  s i m u l a t i o n model  energy  flows  b u i l d i n g and  day o f each month o f  i n the t a b l e s are the  hourly solar  energy  inputs  t o the g r e e n h o u s e which  r a d i a t i o n captured  sensible  heat  livestock  contained  b u i l d i n g that  by t h e p l a n t  canopy and t h e  i n the v e n t i l a t i o n is potentially  a i r from t h e  available for  recovery  and use by the a t t a c h e d  greenhouse.  Appendix  H, a l s o show t h e h o u r l y  heat  greenhouse energy the heat  from which  input  from v e n t i l a t i o n  actual hourly i s recovered  Tables  heating  the  greenhouse heat  and  the h o u r l y  The t a b l e s i n  losses  heating  from t h e  load  load  when  heat  as w e l l as  the l i v e s t o c k s e n s i b l e The l a s t  two columns i n  a r e r e s p e c t i v e l y , the h o u r l y loss that  fraction  i s supplied  o f the h e a t i n g  recovery  from  the swine  f r a c t i o n of  by p a s s i v e  load  solar  ( a f t e r the  c o n t r i b u t i o n of s o l a r r a d i a t i o n ) that  sensible  when t h e  a i r i s neglected  are c a l c u l a t e d .  H . l t o H.12  passive  the h o u r l y  i n c l u d e the  i s s u p p l i e d by  building  ventilation  air. For contained  the p u r p o s e  i n A p p e n d i x H i s summarized  T a b l e 5.1 c o n c e n t r a t e s the  o f d i s c u s s i o n , the i n f o r m a t i o n  attached  contribution ventilation  on the p a s s i v e  greenhouse h e a t i n g of s e n s i b l e heat  i n Tables  s o l a r c o n t r i b u t i o n to  load while  recovery  a i r to the greenhouse  5.1 and 5.2.  T a b l e 5.2 g i v e s t h e  from  heating  t h e hog b u i l d i n g  load.  MONTHLY AVERAGE HEAT LOSS, SOLAR ENERGY SOLAR ENERGY U T I L I Z E D OF  BY THE GREENHOUSE  FLOOR AREA FOR THE ATTACHED  INPUT AND  IN MJ PER m  GREENHOUSE-SWINE  FINISHING BARN OF CASE STUDY I I I (MINIMUM GREENHOUSE  TEMPERATURE = 15°C)  HALIFAX, N.S.  Solar  Heat Month  ^° , 2 S S  MJ/m  Energy  C a_p.t u r e d ,MT/_2I (MJ/m )  Used (MJ/m )  Utili. Factor  x  2  Percent Supplied by S o l a r  January  481  156  116  0.74  24  February  441  202  128  0.63  29  March  405  335  144  0.43  36  April  280  369  111  0.30  40  May  166  436  65  0.15  39  June  69  493  18  0.04  25  July  24  479  3  <0.01  13  August  18  458  3  <0.01  16  September  50  350  10  0.03  19  October  159  255  44  0.17  28  November  265  140  69  0.49  26  December  424  114  93  0.82  22  Year  2782  3787  804  0.21  29  MONTHLY AVERAGE HEATING LOAD, WASTE TO THE GREENHOUSE BUILDING  AND  HEAT CONTRIBUTION  HEATING LOAD FROM THE LIVESTOCK  SUPPLEMENTAL HEAT REQUIREMENT  OF GREENHOUSE  IN MJ PER  m  2  FLOOR AREA FOR THE ATTACHED GREENHOUSE-  SWINE FINISHING BARN OF CASE STUDY I I I (MINIMUM GREENHOUSE TEMPERATURE = 1 5 ° C ) HALIFAX, N.S.  Month  Heating Load (MJ/m ) 2  Waste Heat Contribution (MJ/m ) 2  Supplemental Heat Requirement (MJ/m )  Percent S u p p l i e d by Waste H e a t  2  January  365  54  311  15  February  313  46  267  15  March  261  52  209  20  April  169  55  114  32  May  101  61  40  61  June  51  51  0  100  July  21  21  0  100  August  15  15  0  100  September  40  40  0  100  October  115  82  33  71  November  196  75  121  39  December  331  64  267  19  1978  616  1362  31  Year  The the  c o n s t r u c t i o n parameters  greenhouse  conventional the  gable  exception  livestock this  here  greenhouse  of the presence  building.  chapter  Chapter  analyzed  are i d e n t i c a l described  to the  i n Chapter  the r e s u l t s  comparable  to results  and summarized  i n Table  4.4 o f t h a t  Comparison  of the r e s u l t s  indicate  that  the a t t a c h e d  meter o f f l o o r the  free  area  standing  of  25 p e r c e n t  of  the greenhouse  loss.  greenhouse  which  greenhouse.  hand, t h e s o l a r i s lower  The  s i x percent  reduction  the  insulated  area;  740 MJ/m  2  north  than  radiation  that  a reduction  values  metre o f f l o o r i n energy  captured  captured  area  capture  w a l l of the a t t a c h e d  a r e 3787 and annually.  i s attributed to  greenhouse.  975 t o 804 m e g a j o u l e s p e r s q u a r e  the n e t r e d u c t i o n  The a n n u a l  i n greenhouse  by t h e  by t h e f r e e  c o n t r i b u t i o n t o the greenhouse  o r 27 p e r c e n t  greenhouse.  represents  The c o r r e s p o n d i n g  per square  floor  2  i s due t o i n s u l a t i o n  4024 m e g a j o u l e s  from  t o 3693 MJ/m f o r  2  heat  standing  reduced  per square  and t h e e l i m i n a t i o n o f i n f i l t r a t i o n  greenhouse  was  loss  wall  attached  the s o l a r  heat  of the north  On t h e o t h e r  though,  chapter.  i s 2782 m e g a j o u l e s  This  5.1 o f  obtained i n  the annual  (MJ/m ) as compared  greenhouse.  4 , with  of Table  4  from  p r a c t i c e s of  o f a common w a l l w i t h t h e  Therefore,  are d i r e c t l y  and management  Even  heat  loss  meter o f  heating  load i s  i n favor of the attached solar  energy  utilization  f a c t o r was  reduced  from  Chapter  4) t o 0.21 f o r t h e a t t a c h e d g r e e n h o u s e  Chapter  5).  factor  0.24  f o r the f r e e  s t a n d i n g greenhouse  The l o w e r i n g o f t h e s o l a r  i s due t o t h e r e d u c e d  heat  energy  loss  from  ( T a b l e 5.1, utilization  the attached  greenhouse.  T a b l e 5.2 g i v e s t h e p r e d i c t e d m o n t h l y  contribution  t o t h e greenhouse  supplied  The m o n t h l y  percentage  by w a s t e h e a t  i n January  from  a i r of the l i v e s t o c k  o f greenhouse  heating load  t h e hog b a r n r a n g e d  from  15 p e r c e n t  t o 100 p e r c e n t d u r i n g t h e summer months g i v i n g an  annual p r e d i c t e d  average  i n t h e o r d e r o f 30 p e r c e n t .  case  study, the expected annual  heat  are about  area.  and a n n u a l  heating load of sensible  waste h e a t r e c o v e r y from v e n t i l a t i o n building.  ( F i g . 4.3,  600 m e g a j o u l e s  The p r e d i c t e d  annual  s a v i n g s i n energy  from  p e r square metre o f  supplemental  In t h i s waste  greenhouse  heat requirement f o r 2  the a t t a c h e d greenhouse 2 compared  t o 2718 MJ/m  greenhouse. of  In Chapter  a five  temperature  to determine  that  lowering the  by one d e g r e e i n the annual  o f an a n a l y s i s w h i c h  the e f f e c t  as  standing conventional  T a b l e s 5.3 and 5.4 o f t h i s  the r e s u l t s  i s 1362 MJ/m  4, i t was c o n c l u d e d f r o m  percent reduction  requirement. of  f o r a free  a c o n v e n t i o n a l greenhouse  minimum i n s i d e in  t o t h e hog b a r n  the a n a l y s i s  greenhouse  K e l v i n has r e s u l t e d supplemental  heat  c h a p t e r g i v e a summary  i s performed  primarily  o f l o w e r i n g the greenhouse  minimum  MONTHLY AVERAGE HEAT LOSS, SOLAR ENERGY SOLAR ENERGY U T I L I Z E D BY THE GREENHOUSE OF FLOOR AREA FOR THE ATTACHED FINISHING BARN (MINIMUM GREENHOUSE  INPUT AND  IN MJ PER  m  2  GREENHOUSE-SWINE  OF CASE STUDY I I I TEMPERATURE = 1 0 ° C )  HALIFAX, N.S.  Month  Heat Loss, 2 M  J  /  m  S o l a r Energy _ „ , , Captured Used (MJ/m ) (MJ/m ) 2  . •, . Utili. Factor  rTi  ~ , _ ,. , Percent Supplied by S o l a r J  January  364  156  88  0.56  24  February  334  202  100  0.50  30  March  289  335  103  0.31  36  April  166  369  61  0.17  37  May  62  436  14  0.03  23  June  14  493  2  <0.01  14  September  -  October  52  255  November  153  December  July August  Year  0.00  -  6  0.02  12  140  37  0.26  24  306  114  69  0.61  23  1740  3787  480  0.^13  28  479 458 350  -  0.00 0.00  MONTHLY AVERAGE HEATING LOAD, WASTE TO THE GREENHOUSE  HEAT CONTRIBUTION  HEATING LOAD FROM THE LIVESTOCK 2  BUILDING  AND  SUPPLEMENTAL HEAT REQUIREMENT  OF GREENHOUSE  IN MJ PER m  FLOOR AREA FOR THE ATTACHED GREENHOUSE-  SWINE F I N I S H I N G BARN  OF CASE STUDY I I I  (MINIMUM GREENHOUSE TEMPERATURE = 10°C) HALIFAX, N.S.  Month  Heating Load (MJ/m ) 2  Waste Heat Contribution (MJ/m ) 2  Supplemental Heat Requirement (MJ/m )  Percent S u p p l i e d by Waste H e a t  2  102  174  37  234  83  151  36  March  186  94  92  50  April  105  87  18  83  May  48  48  0  100  June  12  12  0  100  July  -  -  August  -  September  -  -  October  46  46  0  100  November  116  108  8  93  December  237  115  122  49  1260  695  565  55  January  276  February  Year  ^  -  -  -  temperature  on t h e s u p p l e m e n t a l  attached  greenhouse  analysis  the g r e e n h o u s e  150C  annual  heat  finishing  minimum  barn.  temperature  o f an For t h i s  was  reduced  loss  o f T a b l e 5.1 t o T a b l e 5.3 i n d i c a t e s from  1740 m e g a j o u l e s  minimum  remained  the s o l a r  0.21  setting  factor  was d r o p p e d  radiation  has been  i n the s o l a r t o 0.13  was r e d u c e d  metre o f f l o o r  from  reduced  energy  from  2782  15°C t o 10°C.  the s o l a r  greenhouse energy  significantly.  utilization  i s due t o t h e l o w e r  from  that the  a r e a when the  c a p t u r e d by the  t h e same, b u t , as e x p e c t e d  utilization decrease  the greenhouse  per square  temperature  Obviously  of  requirement  t o 10°C. A comparison  to  t o a swine  heat  factor  greenhouse  from  The a value  operating  temperature. The m o n t h l y and y e a r l y heat  r e c o v e r y from  heating  load  temperature  t h e hog b a r n  of s e n s i b l e  waste  to the a t t a c h e d  greenhouse  i s shown . i n T a b l e 5.4 f o r a minimum  greenhouse  setting  5.2(15°C) t o t h o s e the h e a t i n g s e a s o n and  contribution  the annual  o f 10°C.  Comparing  the v a l u e s i n T a b l e  i n T a b l e 5.4 (10°C) i n d i c a t e was r e d u c e d  heating load,  waste h e a t , was r e d u c e d  from  from  firstly  that  12 months t o 9 months  neglecting  the c o n t r i b u t i o n o f  1978 t o 1260 m e g a j o u l e s  per  square metre o f f l o o r contribution during  area.  S e c o n d l y , t h e waste  t o t h e greenhouse  t h e w i n t e r months.  heat  h e a t i n g l o a d was i n c r e a s e d  The a n n u a l c o n t r i b u t i o n o f w a s t e  h e a t r e c o v e r y from t h e hog b a r n t o t h e greenhouse  heating  l o a d has i n c r e a s e d  greenhouse  temperature of  10°C.  based  from  o f 1 5 ° C t o 55 p e r c e n t f o r a minimum  Thirdly,  t h e annual  upon g r e e n h o u s e  1362  MJ/m  10°C  respectively.  energy  temperature  Table used  a r e a has d e c r e a s e d  r e p r e s e n t s about that  factor  The s i g n i f i c a n c e  The g r e e n h o u s e  from  o f 1 5 ° C and  60 p e r c e n t i n  greenhouse  operating  f o r a greenhouse-livestock  o f l o w e r i n g t h e minimum  temperature  greenhouse-swine  5.5.  requirement  f o r minimum t e m p e r a t u r e s  indicates  operating  temperature  supplemental heat  floor  i sa significant  combination. greenhouse  2  This  s a v i n g s which  attached  unit  t o 565 MJ/m  2  31 p e r c e n t f o r a minimum  on e n e r g y  finishing  s a v i n g s f o r an  barn i s evident  minimum o p e r a t i n g  from  temperatures  i n t h e a n a l y s e s r e p r e s e n t e d i n T a b l e 5.5 a r e 20°C, 1 5 ° C  and  10°C r e s p e c t i v e l y .  the  table  energy  a r e based  The p e r c e n t e n e r g y  upon t h e 20°C  case.  s a v i n g s shown i n  The p r e d i c t e d  s a v i n g s due t o l o w e r i n g t h e g r e e n h o u s e  temperature  from  20°C  annual  minimum  t o 1 5 ° C a n d 1 0 ° C a r e 52 a n d 80 p e r c e n t  respectively. As p r e v i o u s l y this  study i s t o determine  recovering using  stated,  t h e waste heat  t h e main purpose the potential  of Part  energy  from a l i v e s t o c k  II of  s a v i n g s by  o p e r a t i o n and  i t t o p a r t i a l l y s u p p l y t h e h e a t i n g demand o f an  E F F E C T OF LOWERING  THE MINIMUM  GREENHOUSE  TEMPERATURE ON ENERGY SAVINGS FOR THE ATTACHED  OF CASE STUDY I I I HALIFAX,  N.S.  S u p p l e m e n t a l Heat (MJ p e r m Greenhouse F l o o r Area) 2  Month  Percent  Savings  =15°C  T =10°C g  T =20°C 9  T =15°C g  T =10°C g  January-  462  311  174  33  62  February  395  267  151  32  62  March  339  209  92  38  73  April  235  114  18  51  92  May  159  40  0  75  100  June  100  0  0  100  100  July  64  0  0  100  100  August  59  0  0  100  100  September  99  0  0  100  100  October  189  33  0  82  100  November  280  121  8  57  97  December  433  267  122  38  72  2814  1362  565  52  80  Year  T g  adjacent  greenhouse.  finishing  barn  significant operation  i s used  energy  i n Table  highly  study,  o f a swine  as an example t o d e m o n s t r a t e i f  s a v i n g s c o u l d be a c h i e v e d  system o p e r a t e d  5.6.  as c a n c l e a r l y the p r e d i c t e d  be s e e n  annual  through  combination.  i n the H a l i f a x  The p o t e n t i a l  d e p e n d e n t on t h e minimum  setting  case  of a greenhouse-livestock  of a combination given  The p r o m i s i n g  energy  i n the t a b l e .  greenhouse  of  20°C, 15°C and 10°C r e s p e c t i v e l y .  The above  standing  gable  temperatures percentage  using a conventional  g r e e n h o u s e as a b a s e  case  s a v i n g s were i n t h e o r d e r  f o r minimum  are c a l c u l a t e d  area are  For this  27, 50 and 67 p e r c e n t  savings  results  temperature  of  energy  The  savings are  greenhouse  energy  the  for  free  comparison.  I n many i n s t a n c e s , t h e g r e e n h o u s e o p e r a t o r s c h o o s e t o grow low t e m p e r a t u r e relatively of  higher  the. y e a r .  crops  temperature  F o r such  L e t us t a k e  a low t e m p e r a t u r e through year; heating per  February then  from  and a  the expected  different  from  seasons  annual  energy  the values  given  f o r example, a greenhouse o p e r a t e d a t  o f 10°C d u r i n g t h e months o f November and a t 15°C d u r i n g t h e o t h e r months o f t h e Table  requirements  square  season  crop during the other  a case,  s a v i n g s w o u l d be somewhat above.  during the winter  5.6 , t h e p r e d i c t e d  c a n be c a l c u l a t e d  metre o f f l o o r  area  annual  supplemental  as 2243 m e g a j o u l e s  f o r the c o n v e n t i o n a l  2 g r e e n h o u s e and 851 MJ/m  f o r the attached  resulting  annual  i n an e x p e c t e d  o r d e r o f 62  percent.  energy  greenhouse  savings  i n the  TABLE 5.6 MONTHLY AVERAGE SUPPLEMENTAL HEAT REQUIREMENTS FOR A CONVENTIONAL AND AN ATTACHED (MJ PER m  2  GREENHOUSE  GREENHOUSE*  FLOOR AREA)  ALSO EXPECTED PERCENT SAVINGS AS A FUNCTION OF  THE MINIMUM GREENHOUSE  T  Month  = 20°C g Supplemental Heat Percent Savings Con. Att.  TEMPERATURE  T  = 15°C g Supplemental Percent Heat Savings Con. Att.  T  = 10°C g Supplemental Heat Percent Savings Con. A t t .  January  632  462  27  497  311  37  370  174  53  February  540  395  27  428  267  38  321  151  53  March  464  339  27  357  209  41  254  92  64  April  325  235  28  232  114  51  146  18  88  May  222  159  28  141  40  72  69  0  100  June  135  100  26  69  0  100  17  0  100  July  87  64  26  27  0  100  August  84  59  30  21  0  100  September  -  140  99  29  61  0  100  October  261  189  28  160  33  79  November  387  280  28  272  121  December  603  433  28  453  2814  27  2718  Year * Location:  3880  Halifax,  N.S.  -  -  0  100  68  0  100  56  162  8  95  267  41  322  122  62  1362  50  1736  565  67  7  fO  to  The  above s a v i n g s i n e n e r g y o f the heat  greenhouse,  the minimization of outside a i r i n f i l t r a t i o n  the north wall  t h e g r e e n h o u s e and t h e u t i l i z a t i o n  s e n s i b l e heat produced be  from  t o the  elimination  into  loss  c a n be a t t r i b u t e d  further  system  improved  by t h e a n i m a l s .  i f an e f f i c i e n t  c o u l d be d e s i g n e d  the l a t e n t  heat produced  o f a f r a c t i o n o f the These s a v i n g s c o u l d  latent  and u t i l i z e d  of the  heat  recovery  t o r e c o v e r some o f  by t h e a n i m a l s .  CONCLUSIONS From t h e i n f o r m a t i o n a v a i l a b l e on l e v e l s and  hydrogen  sulfide  air  from  and  on t h e t o l e r a n c e o f p l a n t s  animal  concluded  c o n c e n t r a t i o n s encountered  shelters  under normal  i n the exhaust  operating conditions,  to these gases,  i t may be  that:  Introducing into  o f ammonia  t h e a i r from  the animal  shelter  directly  the a t t a c h e d greenhouse i s not expected  detrimental greenhouse  effects  on t h e g r o w t h o f a t l e a s t  t o have some  crops. 2  Computer s i m u l a t i o n  a n a l y s e s o f a 1000 m  gable  greenhouse a t t a c h e d t o a c o n v e n t i o n a l swine f i n i s h i n g housing  1536 h o g s , and l o c a t e d  revealed 1.  the following  The y e a r l y could  N.S. a r e a ,  results:  percentage  be s u p p l i e d  i n the H a l i f a x ,  barn  o f the heating requirements  that  by a n i m a l w a s t e h e a t r e c o v e r y i s i n  t h e o r d e r o f 30 p e r c e n t , w h i l e t h e g r e e n h o u s e minimum operating  temperature  was s e t a t 1 5 ° C .  When  this  temperature increased 2.  The minimum g r e e n h o u s e  savings  percentage  t o 55 p e r c e n t .  significant  3.  was r e d u c e d t o 1 0 ° C , t h e above  factor  operating  i n accessing  temperature  the r e a l i z a b l e  from g r e e n h o u s e - l i v e s t o c k c o m b i n a t i o n  The p r e d i c t e d greenhouse  annual energy  systems.  to a  free-standing  h a v i n g t h e same c o n s t r u c t i o n and  management p a r a m e t e r s minimum g r e e n h o u s e respectively.  energy  savings o f the attached  t o t h e hog b a r n compared  gable greenhouse  is a  are:  27, 50 and 67 p e r c e n t f o r  temperatures  o f 20°C,  15°C and 1 0 ° C ,  Symbol C  P  Definition Specific  heat of barn exhaust a i r  Mass f l o w r a t e HRL  SENS  Q  SOL  Q  SUP,G  Sensible Solar  SUP,L  TRAN  o f barn exhaust a i r  heat produced  energy  VENT  - 1  -1  by t h e a n i m a l s  kJ.h  - 1  1  kJ.h"  1  kJ.h"  1  kJ.h"  1  greenhouse heat requirement o f  livestock  building  livestock  loss  building  - greenhouse Q  kJ.h  heat requirement o f  Transmission heat -  kg.h  c a p t u r e d by t h e g r e e n h o u s e k J . h "  Supplemental the  Q  1  building  Supplemental the  Q  kJ.kg~ .K~  S e n s i b l e heat r e c o v e r e d from livestock  Q  Units  Ventilation livestock  heat  from ( e q u a t i o n 1) (equation  loss  from  2) kJ.h  building  Dry-bulb  temperature  o f the barn  K  Dry-bulb  temperature  of the  K  greenhouse  -1  1  PART III  ANALYSIS OF A SOLAR-SHED GREENHOUSE-LIVESTOCK COMBIMATI ON  CHAPTER 6  COMPUTER SIMULATION MODEL OF HEATING REQUIREMENTS OF SOLAR-SHED GREENHOUSE  INTRODUCTION This  chapter gives a d e t a i l e d  greenhouse The  specifically  designed  greenhouse has a shed  Shed" was  a n a l y s i s o f a new  f o r high l a t i t u d e regions.  shape f r o m w h i c h t h e name  a d o p t e d by t h e a u t h o r .  g r e e n h o u s e must be e a s t - w e s t  north wall  i s insulated  t h e upper  collected  and a s o l a r  collector  either  chapter i s divided  g i v e s t h e energy  into  The s e c o n d  theoretical  i s installed  The s o l a r  energy  the greenhouse  three sections.  The  floor. first  b a l a n c e e q u a t i o n s used w i t h t h e computer  s i m u l a t i o n model t o d e t e r m i n e greenhouse.  The  i n a rock s t o r a g e under  t h e b e n c h e s o r i n wet e a r t h u n d e r n e a t h The  oriented.  part of i t s inner surface.  c o u l d be s t o r e d  "Solar-  The l o n g - a x i s o f t h e  solar-shed  at  solar  analysis  the heat  loss  s e c t i o n goes i n t o  of solar  radiation  from t h e  a detailed  c a p t u r e by t h e  p l a n t c a n o p y , as w e l l  a s , an a n a l y t i c a l  estimating  h e a t g a i n by t h e i n t e g r a l  the u s e f u l  technique of solar  collector. The applied  theory developed t o a case  performance is  i n the f i r s t  o f the s o l a r - s h e d greenhouse.  fractions solar-shed estimated  over  The e n e r g y  and t y p e o f  average  solar  savings r e a l i z e d  a c o n v e n t i o n a l gable greenhouse a r e  f o r three locations  i n Canada.  study  c h a p t e r where  temperature  on t h e m o n t h l y and y e a r l y  i s studied.  The c a s e  section of this  o f l o c a t i o n , mean p l a t e  absorber p l a t e  i s then  study i n order t o i n v e s t i g a t e the  the subject of the f i n a l  the e f f e c t  two s e c t i o n s  by t h e  SECTION A  HEAT BALANCE ABOUT THE SOLAR-SHED GREENHOUSE  The chosen  p h y s i c a l model o f t h e s o l a r - s h e d g r e e n h o u s e  forthis  study  i s shown s c h e m a t i c a l l y i n F i g u r e 6.1.  ASSUMPTIONS The the heat  f o l l o w i n g a s s u m p t i o n s were made i n d e t e r m i n i n g balance  i)  o f the greenhouse:  Thermal s t o r a g e  i n t h e greenhouse  structure,  g r o u n d b e d , b e n c h e s and p l a n t c a n o p y i s neglected  t o allow steady  s t a t e heat  transfer  calculations. ii)  Evaporation  from  the s o i l  surface i nthe  greenhouse i s n e g l i g i b l e . iii)  Plants transpiration, respiration  iv)  There the  v)  p h o t o s y n t h e s i s and  are neglected.  i s no i n t e r n a l  energy  inside  greenhouse.  There  i s no c o n d e n s a t i o n  on t h e i n s i d e  of the g l a s s cover, o r dust therefore is  generation  taken  surface  accumulation,  the transmittance of the covering as t h a t o f t h e g l a s s l a y e r  only.  ENERGY BALANCE When a l l t h e above a s s u m p t i o n s were t a k e n the  steady  state  heat  balance  equation  model o f F i g u r e 6.1 i s g i v e n by  into  account,  f o r the physical  SOLAR-SHED GREENHOUSE  FIGURE 6 . 1 :  SCHEMATIC OF A SOLAR-SHED GREENHOUSE SHOWING ENERGY FLOWS AND SOLAR RADIATION INCIDENT ON THE INTEGRAL COLLECTOR.  Q  sup  " sol Q  From F i g u r e energy  " rad  Q  includes the solar  c a n o p y and o b j e c t s  closed  and by r a d i a t i o n infiltration  system t h e heat i s l o s t from the greenhouse  and e x f i l t r a t i o n  an a d d i t i o n a l  always  term i s i n c l u d e d  occur i n greenhouses,  I f the r i g h t  system and/or  Thermal  radiation  and  ground  temperature.  the  r o o f o f t h e greenhouse  walls  temperature,  The t h e r m a l r a d i a t i o n  In  general,  greenhouse  4  v  the thermal r a d i a t i o n w a l l s may be c a l c u l a t e d  equation: Q , . = A. e. o [ F i->-sky ^rad,i I l  isa  sky temperature loss  from  c a n be w r i t t e n a s  4  c  COVER  from the greenhouse  Q = A F .. e a ( T - T , ) + A F rad,roof r r+sky r r sky' r r+g v  by t h e  by t h e f u r n a c e .  loss  o f t h e greenhouse  hand  supplemental heat i s  RADIATION HEAT LOSS FROM GREENHOUSE  function  Since  The s u p p l e m e n t a l h e a t c a n be p r o v i d e d  heating  THERMAL  by c o n v e c t i o n  i n equation ( 1 ) t o account  of equation (1 ) i s negative,  solar  For a  cover.  t h e h e a t l o s s due t o i n f i l t r a t i o n .  required.  radiation  i n the greenhouse  a b s o r b e d by t h e c o v e r i n g m a t e r i a l .  completely  side  (1)  " cond  Q  t o t h e greenhouse  a b s o r b e d by t h e p l a n t  for  " inf  Q  6.1 and e q u a t i o n ( 1 ) i t c a n be s e e n t h a t t h e  input  plus that  ~ con  Q  loss  a (T^-T ) r g 4  r  f r o m any o f t h e  using  the following  .  (2)  For v e r t i c a l  walls,  we  have  F. . = F. = l+sky 1-KJ Therefore equation  Q  reduces t o :  [A, . a / 2 ]  rad, i  [2T«-T* -T<]  e  For the greenhouse  F  ( 3)  0.5  r o o f , we  1 +  (5)  k y  have  COS  (6)  r->-sky  and, cos 6  1  (7)  r+g Inserting we  Q  equations  ( 6)  and  ( 7)  into  (.2)  and  simplifying  obtain,  rad,roof c  = A  r  e o [ r (8)  Evaluation of the  of equations  sky and  The  effective  meterological air  ground  the e f f e c t i v e variables Swinbank  (8)  sky temperature  requires  the  knowledge  i s a f u n c t i o n o f many  s u c h as w a t e r  Several correlation  sky temperature  have been p r o p o s e d ( 1963),  and  temperatures.  variables  temperature.  ( 5)  and  vapour  and  e q u a t i o n s between  the m e t e o r o l o g i c a l  (Brunt (1932),  W h i l l i e r . (1967  content  Bliss  ) , Morse and  Read  (1961)/ (1968))..  In t h i s  analysis  Swinbank's c o r r e l a t i o n  the sky temperature t o the l o c a l is  1  ground  local  ground  during  temperature  be e q u a l t o t h e l o c a l  CONVECTION  accurately,  a i r temperature  in this  study.  c o n v e c t i v e h e a t e x c h a n g e between any s u r f a c e i  the greenhouse  and t h e s u r r o u n d i n g s i s g i v e n by  . = h .A. con,i w,i I  i s related McAdams  for  the l o c a l  COVER  (T.-T ) I a  ,  where t h e a v e r a g e c o n v e c t i v e h e a t t r a n s f e r w  t o the wind  h  w  (10) coefficient,  speed,  (1954) s u g g e s t s t h e f o l l o w i n g  the convective heat t r a n s f e r = 20.52 + 13.68 V  relationship  coefficient: .  CALCULATION OF THE OUTSIDE SURFACE TEMPERATURE ROOF AND The  speed  i t i s assumed t o  HEAT LOSS FROM THE GREENHOUSE  Q  h  from t h e  low wind  Due t o t h e c o m p l e x i t y o f p r e d i c t i n g  surface  The  (9 )  5  s u r f a c e t e m p e r a t u r e may be d i f f e r e n t  a i r temperature e s p e c i a l l y  periods.  of  environmental temperature  used, T . = 0.0552 T * sky a  The  relating  (11)  OF THE  THE WALLS OF THE GREENHOUSE outside  covering material  surface  temperature o f t h e greenhouse  i s dependent  upon t h e o u t s i d e  ambient  temperature,  the i n s i d e  greenhouse  and  Therefore,  to determine  any  wall, If  resistance  walls  and  absorbed  Q  h e a t e x c h a n g e between  the p l a n t  any  =  < > 12  equation  becomes,  r  r  g  r  = A  ca  r  (1  " and  f o r the w a l l s ,  [T  r  - cos  r  A  a  r  X  4  solar  i is:  (8),  f o r the roof  radiation  e q u a l t o a, t h e n t h e  Then, u s i n g e q u a t i o n s  (A /R )(T -T )  the  '  X  of  c a n o p y i s n e g l e c t e d and  surface  i s , i  a  itself.  i s required.  o f the t r a n s p a r e n t cover to s o l a r  by  sa,i  the  flow o f the cover  the w a l l  assumed t o be c o n s t a n t and  energy  of  the o u t s i d e s u r f a c e temperature  the net r a d i a n t  absorptivity  is  to heat  a heat b a l a n c e about  greenhouse the  o p e r a t i n g temperature  (10)  and  - 0.5  B) T ]  (12), the heat  (1 + COS  + h  4  W  /  r  A  8) T ^  r  0.5  a  (  ( 5 ),  -  k  (T -T )  r  s,r  from e q u a t i o n s  balance  (10)  and  1  3  )  (12)  we  get ( A . / R . ) ( T -T.) i l g l  = 0.5 + h  Equations  (13)  and  A. e.a i i  (2T - T l sky 4  wind  speed.  T ) g' 4  . A . ( T . - T ) - A. a. I . w,i l I a i i s,i  (14) may  be w r i t t e n  known m e t e o r o l o g i c a l v a r i a b l e s , and  4  Furthermore,  i n terms  namely l o c a l  (14) of  the  a i r temperature  the o u t s i d e c o n v e c t i v e heat  transfer  coefficients  f o r t h e r o o f and a l l " t h e o t h e r  g r e e n h o u s e w a l l s a r e assumed t o be t h e same.  In r e a l i t y ,  t h e y d e p e n d on t h e w i n d d i r e c t i o n w i t h r e s p e c t t o t h e surface. the  flat  Equation  (11) assumes t h e f l o w i s p a r a l l e l t o  surface.  In a c t u a l s i t u a t i o n s  the wind  may  a p p r o a c h a s u r f a c e a t any a n g l e .  I q b a l and K h a t r y  studied  f l o w on t h e e x t e r n a l  heat  the e f f e c t  o f non-uniform  transfer coefficient  wind t u n n e l ; t h e i r h i g h e r than the  flat  equation  those  i n d i c a t e wind c o e f f i c i e n t  values  o b t a i n e d by a s s u m i n g f l o w p a r a l l e l t o S i n c e wind d i r e c t i o n s  (11) f o r t h e w i n d c o e f f i c i e n t  purpose o f d e v e l o p i n g  to  u s i n g model g r e e n h o u s e s i n t h e  results  surface.  Inserting  (1977)  a r e s e l d o m known,  i s used  f o r the  t h e p r e s e n t greenhouse model.  equations  ( 9) and (11) i n t o  (13) and (14)  obtain:  _ i ( R g r  -t r  T  ) =  (1 + c o s 6)(0.0552  a [ T - 0.5 r r 4  e  (1 - c o s 6)  0.5 +  T ' ) a 1  5  T ] - a I a r s,r 4  (20.52 + 13.68 V ) ( T -T )  (15)  Si  IT  and  Rj  (  V i T  )  =  ~T~ +  [  2  T  i"  (  0  -  0  5  5  2  T  a'  (20.52 + 13.68 V)  5  )  ~ a  4  T  equations  is  taken  "  a  t o the l o c a l  J  s , i (16)  a  (15) and (16) t h e g r o u n d s u r f a c e  t o be e q u a l  i  (T.-T ) l  In  ]  temperature  a i r temperature.  The  overall  r e s i s t a n c e s t o heat  estimated  using R^ = r  flow  R  and  r  the f o l l o w i n g standard (1/f.  1, r  ) + R  may  be  equations: (17)  c  and  i  R  =  {  1  /  i , i  f  ]  +  R  c  ( 1 8  The i n s i d e s u r f a c e  film  surfaces  i n ASHRAE Handbook  are given  resistance  R  coefficients,  f^, for non-reflective (1977).  depends whether t h e c o v e r  c  >  The  cover  i s s i n g l e or double  glazed.  with  Equation  (15) w i t h  equation  (18) may  surface  temperatures  Then t h e t o t a l  heat  equation now  (17) and e q u a t i o n  be s o l v e d  A  and  r  the t o t a l Q  The t o t a l  ±  heat =  and  walls.  l o s s from the r o o f i s : R  '  T  r  g  l o s s f r o m any w a l l  (A /R ) ±  f o r the e x t e r n a l  f o r the greenhouse r o o f  Q = < / ) ( -V r  (16)  (T - T )  i  (convective  i ,is  .  r  plus  (19)  (2,0)  r a d i a t i v e ) heat  g r e e n h o u s e c a n t h e n be c a l c u l a t e d as  l o s s from the  follows:  Q=^ r g~V i i g" i ' r=l i=l where m is the number of roof slopes making up the greenhouse roof and n the number of vertical walls for the greenhouse under consideration. (A  /R  r  ) (T  +  ( A  / R  }  (T  T  )  (21)  CONDUCTION HEAT LOSS FROM THE GREENHOUSE The through  conduction heat  heat  transfer  floor  i s included  the heat  loss  i n the perimeter  loss. The  as  Here i t i s assumed t h a t  t h e greenhouse  heat  includes  t h e g r e e n h o u s e p e r i m e t e r and t h r o u g h t h e  foundation. to  loss  conductive heat t r a n s m i s s i o n i s then  calculated  follows: Q  , = U- A,. (T -T ) + U P cond f f g a p  (T -T ) g a  .  (22)  INFILTRATION HEAT LOSS FROM THE GREENHOUSE The  air-exchange  gable greenhouse heat  method u s e d w i t h r e s p e c t t o t h e  i s employed h e r e .  Therefore the sensible  l o s s due t o i n f i l t r a t i o n / e x f i l t r a t i o n may be  estimated  using the following  '  Q. , = inf  (1/v) C  p  V  equation: N  g  a  (T -T ) g a  (23)  SUPPLEMENTAL HEAT REQUIREMENT The  supplemental  may be c a l c u l a t e d  sup  =  heat  requirement  f o r the greenhouse  by t h e u s e o f e q u a t i o n (1) Q  w  s o l-  , - Q - Qv .  *  where Q = Q rad  , + Q con  as d e f i n e d by e q u a t i o n ( 2 1 ) .  mf  . c - 0  ^cond  (24)  Finally,  the  daily  heating  simply:  load  f o r the  greenhouse i s  24 Q  , day  sup,  = >  z/  J  Q  (26)  -sup  hour=l The  minus s i g n i n d i c a t e s t h a t o n l y  considered The by  Q  2  during  the  solar r a d i a t i o n input  , i n equation sol ^  this  chapter  solar  summation  (24)  where an  energy captured  f o r m may  be Q  written . sol  In e q u a t i o n  =  (27),  the  I  g  the  = 1 + 1 p term I  roof  i n d i c a t e t h a t the and  respectively. c  by  equations  the  vertical  w  the  total  the  and  .  (27) the  total  p l a n t canopy.  amount The  terms  r a d i a t i o n i s o r i g i n a t i n g from  walls  of  Detailed expressions (49)  the  i n i t s simplest  represents  and  the  represented  as,  I  w  are  next s e c t i o n of  for estimating  This expression  s o l a r r a d i a t i o n a b s o r b e d by I  greenhouse  p l a n t canopy i n s i d e  of p  t o the  i s t r e a t e d i n the  by  values  process.  expression  greenhouse i s d e r i v e d .  negative  the  greenhouse  for I  (47) r e s p e c t i v e l y .  p  and  I  w  are  given  SECTION B CALCULATION OF SOLAR RADIATION CAPTURE BY A SHED-GREENHOUSE AND SOLAR RADIATION INCIDENT ON THE COLLECTOR  CALCULATION OF SOLAR RADIATION CAPTURE BY A SHED-GREENHOUSE AND  SOLAR RADIATION  INCIDENT ON THE COLLECTOR  ASSUMPTIONS For i.  this analysis  The p l a n t  the following  canopy r e f l e c t s  whether the o r i g i n a l diffuse ii.  reflection  greenhouse cover The r e f l e c t a n c e is iv.  d i f f u s e l y regardless  incident  of  r a d i a t i o n i s beam o r  i n nature.  Multiple  iii.  a s s u m p t i o n s were made:  is  between t h e p l a n t  c a n o p y and t h e  neglected.  of the c o l l e c t o r to the solar  radiation  small.  The c o n t r i b u t i o n  of the east  greenhouse i s n e g l e c t e d .  and w e s t end w a l l s  (L >>  of the  W)  ESTIMATION OF THE TOTAL SOLAR RADIATION INCIDENT ON THE FLAT PLATE SOLAR COLLECTOR INSIDE A SHED-TYPE GREENHOUSE The the  total  s o l a r r a d i a t i o n i n c i d e n t on t h e c o l l e c t o r i s  sum o f t h e t o t a l  s o l a r r a d i a t i o n from t h e r o o f  of the  g r e e n h o u s e , a f r a c t i o n o f t h e d i f f u s e r a d i a t i o n r e f l e c t e d by the  top of the plant  radiation surface Or  c a n o p y and a f r a c t i o n o f t h e d i f f u s e  from t h e p l a n t s  that  i s r e f l e c t e d by t h e i n n e r  of the roof. mathematically, I  =  c  I  u b , c + I d,c , + 1 r,p + 1 r , r  (28) '  v z  where t h e f i r s t  t e r m i n t h e summation r e p r e s e n t s t h e beam  solar  transmitted  radiation  is  incident  on t h e s o l a r  be  e s t i m a t e d by: I, b,c  The  second term  through the greenhouse r o o f  collector.  = I, b,v  T,  b,r  i s the d i f f u s e  This diffuse radiation factor  radiation  transmitted  Then t h e t o t a l s o l a r neglecting  u  The  last  the  reflected  that  A  radiation  i s incident  solar  in  the equation  of  the plant  T,  d,r  radiation  This portion  radiation  A  A  solar  i s the d i f f u s e  F r r-*c  form, (30)  on t h e c o l l e c t o r  F  r  .  r+c  (31) ' the f r a c t i o n of  collector.  radiation  radiation =  ?I  The t h i r d  term  on t h e c o l l e c t o r .  may be e x p r e s s e d a s :  'p,i P P-=  term i n equation reflected  canopy  r e f l e c t e d by t h e t o p  i s d i r e c t l y incident  of the d i f f u s e  radiation  configuration  from t h e t o p o f t h e p l a n t  the v e r t i c a l s o l a r  the fourth  solar  components i s :  V.p - e ^ Vc Finally,  on t h e c o l l e c t o r .  and t h e  incident  + I, T, d , r d , r  canopy t h a t  transmitted  from t h e d i f f u s e  two t e r m s i n e q u a t i o n (28) r e p r e s e n t  i s reaching  diffuse  (2 9)  and t h e c o l l e c t o r , o r i n e q u a t i o n  = I, d,r  c  may  .  c  through the roof  the r e f l e c t e d  I ' = I,_ T c b,vb,r  A  c a n be e s t i m a t e d  between t h e r o o f I, d,c  T h i s beam r a d i a t i o n  solar  through the greenhouse r o o f t h a t  that  a  F  (32)  (28) r e p r e s e n t s t h e  by t h e t o p o f t h e p l a n t  canopy  and  reaching  the  solar  of  r e f l e c t i o n of  In  equation  be  written  X  I  I' + c  c  =  i n d i r e c t l y v i a the  surface of of  the  the  process  greenhouse  diffuse  roof.  radiation  may  as:  Therefore, the  inner  form, t h i s p o r t i o n  r,r  with  the  collector  =  P p  Vr  J  the  total solar  reflected  T  d,r  "  a  r  radiation  )  F  +  I' F p p->r  p  r+c  '  incident  components i n c l u d e d  I' F p p-*c  p  "  ( 1  (1 -  may  ( 3 3  on  be  the  collector  estimated  x, „ - a ) F _ ^ d,r r r-»-c  >  by:  .  (34)  But, F  therefore  c  =  J  equation  Z  c  +  p  J  [ P  =  p+r  (A /A ) F r' p r-»-p  ,  (35)  (34) becomes:  Vc  +  (  Vp A  )  ( 1  -  T  d,r  " V  F  r + p r->c F  ]  (36) where t h e  s e c o n d t e r m on  represents plant  solution  total solar  canopy.  This  beam and  diffuse  through the  r i g h t hand  total reflected  canopy t h a t The  the  the  the  radiation  i s r e a c h i n g the of equation  radiation  amount o f  roof of  the  solar  by  radiation  on may  solar  g r e e n h o u s e as  of  equation  the  top  of  (36)  the  collector.  (36) r e q u i r e s  incident  components o f  side  the be  the top  knowledge of  the  estimated  radiation follows:  of  plant  from  the  transmitted  i.  Beam  radiation  incident  b, p i i .  Diffuse  b, n  radiation  on t h e t o p o f t h e p l a n t  b, r  canopy:  p  incident  on t h e t o p o f t h e  plant  canopy:  I  Then  the total  Tj A F d, r r r->-p  = Ij  d,p  d,r  solar  radiation  .  incident  (38)  on t h e t o p o f t h e  plant  canopy i s :  I ' = I, , p  T  b,h  W  Combining  equations  radiation  reaching  1 = 1 ,  T,  c  b,v  + F  b,r  I, d,r  a  J  F  r  F r->-p  .  (39)  (39) t o g e t t h e t o t a l  solar  K  , A F ] d,r r r+p  [F p+c  (A /A ) (1 r' p  +  T  , d,r  a ) r (40)  X  greenhouses  T  b,r  Therefore,  +  J  r+p  T  F r-+c  slope  T  F  as  F  c  o  s  e  P  s e c 81  c  incident  equation  d , r d , r r+c  d,r d,r r +  of different  radiation  of the roof  b,v  +  A  + I, T, A F + p [I, , T, „ A d,r d,r r r+c b,h b,r p  c  i s needed.  =  d,r  (31), (36) a n d  the solar  function  ^,1  T,  d,r  the collector  comparing  locations, area  A  + I,  p  F ] r->-c  r-*p  For  T  A  b,r  B  ]  c  o  slopes  on a u n i t  (40) may  and  collector  be r e w r i t t e n  as  follows:  s  [ F P  •  roof  e  c  +c  B  +  P  +  d  [ I  b,h  T  b,r  " ^d,r "  c  o  r  a  t  B  ]  (  4 1  )  ESTIMATION OF  THE  TOTAL SOLAR RADIATION CAPTURED BY  THE  PLANT CANOPY For  a long east-west oriented  contribution  of  input  may  be  neglected.  input  to  the  of  the  solar  plant  east  and  west w a l l  Therefore,  to  the  and  the  vertical  energy capture of  a l b e d o and  the  type of  solar  total  greenhouse i s through the  south roof  The the  the  shed-type greenhouse, radiation  solar  transparent  south  the  facing  energy surfaces  wall.  the  g r e e n h o u s e d e p e n d s upon  the  greenhouse  covering  material. The plant I  p  =  total  c a n o p y may I-  (1 -  Then u s i n g I  p  =  I'  the  For  the the  p)  total  p  (35)  wall  as  p(l of  x^  the  beam and  the  into  equation (A /A )  r  r  vertical  diffuse  F^  r  - a )  r  (39)  - a )  d / r  top  p  as  the follows:  (1 -  p  (42) F^ ]  we  get:  south  g r e e n h o u s e may  solar  (42)  p).  .  p  transparent the  of  radiation  (43) wall be  incident  follows:  =1,  diffuse I, d,w  x  for F ^  beam component o f  f o r the  (1 -  r  by  from e q u a t i o n  energy capture of  from the  I. b,w and  I' F ^  tl +  solar  captured  estimated  p  +  radiation  contribution  calculated on  p)  be  equation  (1 -  The to  solar  =  b,v  radiation  T.  b,w  A  w  component, we I, d,v  T,  d,w  A  w  we  ,  have: (44)  have: .  (45)  j  Therefore,  the  south w a l l  that  X  w  =  (I  b,w  +  I  d,w  total  solar radiation transmitted  i s captured  )  -  ( 1  P>  [ 1  by  P  +  the  plant  - d,w  ( 1  the  canopy i s :  " *w  T  through  •  )]  ( 4 6 )  or, I  w  = (I. b,v  +1,  T.  b,w  ) A  T,  d,v  d,w  w  (1 -  K  p)  [1 +  p  p(l -  x, „ - « ) ] d,w ^w (47)  Therefore,  the  inside  g r e e n h o u s e may  the  total  s o l a r energy captured be  estimated  by  the  plant  from e q u a t i o n s  canopy  (43)  and  (4.7) . 1 = 1 + 1 g p Due  to the  incident roof.  p  =  (39)  area  b,h  [1 +  A  Tj  (I, ,  L  d,r  y  and A  , = p,l  v  +  p ( l - T. d,r  (1^ , b,h [1 +  x, b,r p(l -  by  an  p  When e x p r e s s e d p e r  I  and  energy captured  surface  the  plant  canopy, a p o r t i o n  r a d i a t i o n i s r e f l e c t e d , then  Equations  solar  I  albedo of  (48)  w  (4 3) the  top  I ,  a  r  d,r  )  d,r  a  a plant  r  F  r-vp  )  (1 -  2  floor  i j d,r -  of  combined  (A /A ) F ] r p r^-p  unit plant  + I, d,r  A  T,  d,r  be  r  )  through the to give  the greenhouse the  canopy h a v i n g  total a  p.  albedo  -  T,  may  lost  of  F r^-p F  2  r^-p  area,  sec sec  M  6]  g)  H  p)  . we  (49) get:  (1 .  w  p)  (50)  Equation  (39) g i v e s t h e t o t a l s o l a r  on t h e t o p o f t h e whole  plant  canopy.  solar  e n e r g y may be e x p r e s s e d  floor  area, as:  I' p,l  X  w,l  ( I  o f t h e south w a l l  area o f plant  equation  =  i n terms o f u n i t  (47).  b , v b,w T  d  may a l s o  passive  solar  collection the  /  ) ( H  outside  /  -  W ) ( 1  (H/W)  p  )  a g r e e n h o u s e may be t r e a t e d  incident This  (50) and (52)  energy captured t o  on a h o r i z o n t a l  surface  e f f i c i e n c y c a n be e s t i m a t e d  ( > 53  K  or <1/I >  [ ( I  h  (1  +  b,h  + p(l- T  J  d , v d,w) T  T  + I, T , F s e c B) (1 - P) r r dr. b , r r d , rd d. , +r p r+D +  d  f  (  H  X  T  F  - a > F ^  r  r  /  W  )  (  1  from  as:  n  =  as a  The e f f i c i e n c y o f s o l a r  i s the r a t i o o f the t o t a l solar radiation  PLANT CANOPY  E = ( Ip , l, + Iw , l ) / ( I b ,>h + Id,n , u>  E  for  (52)  c o l l e c t i o n system.  t h e greenhouse.  equations  (51)  - a j ] .  W  canopy w i t h i n  total solar  greenhouse  be e x p r e s s e d i n  EFFICIENCY OF SOLAR CAPTURE BY THE GREENHOUSE The p l a n t  incident  Thus,  T  [1 + p ( l - x  this  c a n o p y by s u b s t i t u t i n g  *d,v d , w  +  incident  sec B •  L  terms o f u n i t in  Likewise,  = I, , x, + I, T, F b,h b , r d , r d , r r+p  The c o n t r i b u t i o n  radiation  "  p  )  U  s e c B) + d  p  +  p  (  1  b  /  V  " d,w " w T  a  T  ) } ]  F A F  (  5  4  )  T, , T , , x, , T , , a and a are o p t i c a l b,r' d , r ' b,w' d,w' r w  properties of  c  the  transparent  p i s an o p t i c a l  covering  material.  property  of the plant  canopy,  and H, W,  and 6 a r e g r e e n h o u s e c o n s t r u c t i o n  F  The  length  o f t h e g r e e n h o u s e does n o t a p p e a r  in  the equations but i t s e f f e c t i s included  of  the c o n f i g u r a t i o n  The  and t h e t h e r m a l e n e r g y  greenhouse system present  i s outside  work i s i n t e n d e d  storage  only  on  l o s s and i t s s o l a r e n e r g y  portion  D.  upon t h e o v e r a l l study,  as a f e a s i b i l i t y  the e f f e c t of changing  radiation  determination  of the s o l a r  the scope o f t h i s  investigate i t s heat  i n the  COLLECTOR  e f f e c t s o f t h e t y p e and e f f i c i e n c y  collector  explicitly  f a c t o r s a s shown i n A p p e n d i x  USEFUL ENERGY GAIN OF THE SOLAR  the  parameters.  p  IT  since  study t o  t h e shape o f t h e g r e e n h o u s e input.  Only the s o l a r  i n c i d e n t on t h e i n t e g r a l c o l l e c t o r and t h e e s t i m a t e d  that  i s a v a i l a b l e f o r immediate use o r s t o r a g e i s  predicted. The collector of  total  located  the north  previously, by  s o l a r r a d i a t i o n i n c i d e n t on a f l a t  wall  a t the upper p o r t i o n o f the i n n e r o f the shed-type greenhouse  and t h e f i n a l  equation (40).  plate side  i s derived  r e s u l t of the d e r i v a t i o n i s given  The an  approximate  energy  the  and  following  the  from  thermal  (55) may  and of  4  4  T  and  c  of  and  may  be  plate  the  considered mainly Thus,  c  - £ )/£ A c ' c c  +  t h e r i g h t hand s i d e  heat  absorbed  loss.  The  determined  The  solar  by  roof by  equation  (1/A ' r  F  r+c  )  of equation  the  collector  temperature  t h e use  radiation  calculated  of  incident  using equation  are the a b s o r p t i v i t y  the e m i s s i v i t y  solution  the average it  £  material  of equation temperature,  t a k e n as a c o n s t a n t .  and,  e  to thermal (56) T  .  requires As  for solar  i s the  of  emissivity  radiation. the knowledge o f  a first  Thus, l e t  on  (41).  for infra-red radiation  respectively;  the greenhouse roof The  greenhouse  (56)  , c a n be  (17).  the absorber p l a t e ,  the  .  radiation  radiation  c  and  approximated  o f the absorber p l a t e ,  (T - T ) / C ( l c '/ *  solar  the greenhouse,  radiation  inside  to the greenhouse c o v e r .  e x p r e s s i o n s on  constants a  be  (55)  sides  (1 - e )/£ A J" } r r r  (15)  solar  w  r  the thermal  finding  - Q. loss  t h e c o l l e c t o r , I , c a n be The  to  as:  {a  -  r e p r e s e n t the  equations  devoted  c o l l e c t a b l e may  the c o l l e c t o r i s t h e r e f o r e  I c  where t h e two (56)  energy  on b o t h  be w r i t t e n  v  be  integral collector.  c o l l e c t o r i s located  radiation  Q , = A a col c c +  the  , = Q , col abs  solar  loss  will  expression:  a i r i s forced  heat by  from  maximum s o l a r  Q  Since  of t h i s section  method f o r d e t e r m i n i n g t h e amount o f  available  The by  remainder  approximation,  T where T  g  usually  = T  c  g,mm  + AT  ,  i s a s e l e c t e d minimum g r e e n h o u s e  ,mm  t a k e n as t h e d e s i r e d  temperature  (57)  and  AT  night  time  i s some s e l e c t e d  between t h e o p e r a t i n g c o l l e c t o r  AT  plate  i n equation  (56)  between t h e c o l l e c t o r function  of the average  plate  f o u r t h power.  The  minimum u s e f u l  temperature  the energy  from the since  the thermal r a d i a t i o n and  selection  consumed by  temperature o f AT  the  collector  as c a n  heat  raised  be  exchange  the greenhouse r o o f  is a  to the  i s d e p e n d e n t upon t h e  o f the energy  the  and  temperature.  as p o s s i b l e ,  plate  difference  temperature  the heat l o s s  s h o u l d be k e p t as s m a l l  seen  inside a i r  temperature  d e s i r e d minimum a l l o w a b l e g r e e n h o u s e In o r d e r t o m i n i m i z e  temperature,  stored,  fans f o r s o l a r  and  energy  upon  collection  and s t o r a g e . A constant absorber plate v a r i a b l e mass f l o w r a t e collector. system,  of the t r a n s p o r t  a complete  energy  to determine  equation  (56)  temperature.  is valid  only  fluid  a  i n the rate  the c o l l e c t o r i s  temperature.*  Therefore,  f o r the case o f c o n s t a n t p l a t e  If i t i s desired  thermal energy  *  b a l a n c e about  the p l a t e  the type of the c o l l e c t o r  to determine  and/or  the e f f e c t  t h e t y p e and  size  of  of the  s t o r a g e ; then m a t h e m a t i c a l models o f t h e s e  components must be  as n e e d e d .  implies  F o r t h e c a s e o f a c o n s t a n t mass f l o w  required  specific  temperature  incorporated within  In most a p p l i c a t i o n s ,  daily  The r e a d e r i s r e f e r r e d t o A p p e n d i x a n a l y s i s of t h i s case.  the  values of  L f o r the  system  energy  detailed  flows  are  d e s i r e d , then  collectable  is  t h e d a i l y maximum s o l a r  energy  simply: u  ss >^ / j  Q , = col,day n  w  Q w  . col  .  +  (58)  sr  The  plus  s i g n i n the  only p o s i t i v e summation  values  r o o f and  collector  the  are  (40).  radiative  heat  equation  These given  collector, roof  of  the  p l a n t c a n o p y and  p l a n t canopy a r e radiation  the  required for  i n c i d e n t on  the  a s o l a r - s h e d g r e e n h o u s e as i n d i c a t e d  the  the  above c o n f i g u r a t i o n the  total  p l a n t canopy w i t h i n the  equation l o s s by  ( 4 9 ) , as w e l l a s , the  integral  for  solar  solar greenhouse calculating  collector  5,  2.2.  The  results 6.2  a range o f  7.5  as  (56).  form, i n F i g u r e  greenhouse with for widths  solar  between  f a c t o r s were c a l c u l a t e d u s i n g F e i n g o l d ' s  i n Figure  graphical  and  the  Furthermore,  i n c i d e n t on by  by  during  radiation  a l s o needed f o r d e t e r m i n i n g  represented  given  considered  factors for diffuse  total  collector  radiation as  the  the  equation  factors  solar  and  estimating  by  are  c o  DIFFUSE RADIATION CONFIGURATION FACTORS  Configuration  integral  of Q ^  indicates that  process.  CALCULATION OF  the  above e q u a t i o n  and  10  are  represented  to Figure  lengths  metres.  6.4  f r o m 10  for a t o 100  equation  in solar-shed metres  and  The of  required  length  slope is  three  c o n f i g u r a t i o n f a c t o r s as a f u n c t i o n  and w i d t h o f a s o l a r - s h e d  greenhouse having  o f 20 d e g r e e s a r e shown i n F i g u r e  the angle  vertical  measured  6.2.  The r o o f  slope  from the h o r i z o n t a l a t the south  w a l l o f t h e g r e e n h o u s e as i n d i c a t e d i n F i g u r e  Configuration factors f o r solar-shed roof  a roof  slopes  greenhouses  o f 3 0 ° and 4 5 ° a r e shown i n F i g u r e s  6.1. having  6.3 and 6.4,  respectively. It factors (>  i s clearly versus  length  that  70 m), t h e e f f e c t s  radiation due  seen from the curves  without final  length  (end w a l l s )  become s m a l l surfaces  significant  relative  t h e edge  to total radiation  o f the greenhouse.  sacrifice  This i s  i n the accuracy  as  Thus, i n such constants  of the analyses  results.  importance  of the roof  6.2, 6.3 and 6.4  slope  on t h e d i f f u s e  between p l a n t c a n o p y , i n t e g r a l increase  decreases the  and w i d t h on t h e  t h e c o n f i g u r a t i o n f a c t o r s may be t a k e n  Examination of Figures  An  greenhouses  t h a t a t l a r g e greenhouse l e n g t h s ,  e x c h a n g e among o t h e r a case,  of both  solar-shed  c o n f i g u r a t i o n f a c t o r s become n e g l i g i b l e .  t o the f a c t  effects  f o r long  for configuration  i n the roof  slope  collector  r e v e a l s the r a d i a t i o n exchange  and g r e e n h o u s e  of a solar-shed  t h e amount o f d i f f u s e  greenhouse  r a d i a t i o n o r i g i n a t i n g from  r o o f t h a t w o u l d be i n t e r c e p t e d by t h e p l a n t c a n o p y .  example,  the value  of  F r  _  i p  s  0.19  roof.  f o r a greenhouse  d i m e n s i o n s o f 100 m by 7.5 m and 2 0 ° r o o f  slope.  For  having This  value  is  reduced  t o 0.675 a n d 0.49 when t h e r o o f  to  3 0 ° and 4 5 ° , r e s p e c t i v e l y . On t h e o t h e r  incident roof  to the roof, value F _ r  c  of F  c-r  i s increased  hand, t h e amount o f d i f f u s e r a d i a t i o n  on t h e i n t e g r a l  slopes;  slope  collector  i s increased  so does, t h e r a d i a t i v e heat since while  this  loss i s directly  i n turn  by t h e f o l l o w i n g A  this  value  f o r steeper  l o s s by t h e c o l l e c t o r p r o p o r t i o n a l to the  i s r e l a t e d to that of  relation,  r  F  r-c  = A  c  F c-r  .  (59)  r-c  1Q2); X 102) ^  X  AND PLANT CANOPY AND COLLECTOR ( Fp - c p  G  o Tl  00  M  o  M O •3  50  O *d  EC  tr M Z  cn f >  i cn  w D  o 50 w  1  H3 EC  o C cn w  cn EC > <  G  cn  s:  w  M  D  EC  z o  »-3 EC  •-3  o  M  EC  O M >  i-3  cn f O  *  O  M  Z  Z  EC  M EC  50 M  H  O  M  Z  O)  a w o w 50  w  cn  z  M O  O W 50 W M cn  •-3 M  o z  >n  H3  o  50 cn  CONFIGURATION FACTORS BETWEEN ROOF AND PLANT CANOPY ( F _ x 1 0 ) 2  r  9SZ  D  COLLECTOR ( F _ x 102) p  c  H  CI G 50 W  CTl  O 50  CO o  >  W *1  *d W  n  >-3  50  o  w a  F  o a  a o a  I  M  50  M  M  w a a o  G W cn  a > H  a  Tl  F  o w o u> o O W  50  w  M  a o  G  a  o •a a o a a w  F W  a o •-3 a H  a a  M  50 o o  M Z  o  > M  o a o o a *j  M •3 50 W  H  o G  O  a  > n ••3 o  CONFIGURATION FACTORS BETWEEN ROOF AND PLANT CANOPY ( F _ x 1 0 ) 2  r  p  CONFIGURATION FACTORS BETWEEf\ PLANT CANOPY AND COLLECTOR (F„_ D-C  *1  o  so cn O  >  so  cn1 EC M O  w •n w n  o z f w  z o  •-3  O  EC  W  >  SO  M Z EC O C cn M cn  EC  > < H  so  M M  z o  EC  Z o  G cn w  H  f  o  EC  M Z Q  O  EC  z  t-3 M  Z  Z  EC  >  (?• o  a  *i  cn f  o  13 M  o  W  D W  >  AM  so o o  102)  Ho  W  •-3  so  > M  O Z  i-3  M cn  o  o z M  o  G D tn  ?» ••3 M  o  o z  M cn •  >  »w  o cn  CONFIGURATION FACTORS BETWEEN ROOF AND PLANT CANOPY ( F _ x 102); AND ROOF AND COLLECTOR ( F _ x 1 0 ) r  p  2  r  c  SECTION C  CASE STUDY IV SUPPLEMENTAL HEATING REQUIREMENTS OF A SOLAR-SHED GREENHOUSE  CASE STUDY I V :  SUPPLEMENTAL HEATING REQUIREMENTS  OF A SOLAR-SHED  DESCRIPTION AND  GREENHOUSE  ASSUMPTIONS  The m a t h e m a t i c a l m o d e l d e v e l o p e d i n s e c t i o n s A and B o f this  c h a p t e r was s o l v e d u s i n g  the h o u r l y passive  transmission  solar  collector  infiltration  loss  and t h e  greenhouse.  s u p p l e m e n t a l h e a t r e q u i r e m e n t as w e l l as  and d a i l y placed  solar  energy  collectable  on t h e n o r t h w a l l  were c a l c u l a t e d . of  loss,  computer t o d e t e r m i n e  e n e r g y c a p t u r e by t h e s h e d - t y p e  Then, t h e h o u r l y the h o u r l y  a digital  Finally  inside  the monthly  by a s o l a r  the greenhouse  average d a i l y  fractions  the supplemental heat requirement o f the greenhouse  c o u l d be s u p p l i e d  by t h e i n t e g r a l  solar  collector  that  were  estimated. Throughout  the time o f the s i m u l a t i o n  the f o l l o w i n g are  assumed t o r e m a i n c o n s t a n t : i)  t h e minimum g r e e n h o u s e  ii)  the i n f i l t r a t i o n / e x f i l t r a t i o n  iii) The  temperature,  the albedo o f the plant solar-shed  greenhouse  l e n g t h o f 100 m e t r e s  used i n t h i s  the greenhouse.  case study has a  i s east-west o r i e n t e d .  s o u t h and t i l t e d  horizontal.  within  and a w i d t h o f 10 m e t r e s .  a x i s o f t h e greenhouse facing  canopy  r a t e , and  An i n t e g r a l  The l o n g The r o o f i s  a t an a n g l e o f 30 d e g r e e s solar  collector,  having a surface  a r e a o f 577 s q u a r e m e t r e s ,  i s installed  of  o f t h e shed greenhouse.  the v e r t i c a l  north wall  from the  on t h e i n n e r  surface The n o r t h  wall,  t h e f o o t i n g and t h e p e r i m e t e r o f t h e greenhouse a r e  insulated. of g l a s s  The g r e e n h o u s e i s c o v e r e d w i t h  having a thickness  properties other  detailed  construction  i n Table  RESULTS AND A  i s included and d a i l y  typical  tables  the  plant  simulation  values  shown i n t h e s e  the passive  indicated  i n this  A summary  the s o l a r input  only;  canopy.  4.2  The  are f o r a  The i n f o r m a t i o n  heat  in  transmission  l o s s , the  the a c t i v e  solar  o f the r e s u l t s o f Appendix  i n Table  6.2.  t a b l e a r e due t o p a s s i v e that  I t i s important  and s o l a r c o n t r i b u t i o n as solar radiation  i s , the s o l a r energy captured  Therefore,  the values  shed-type greenhouse a r e d i r e c t l y Table  tables  (excluding  i s shown, on a m o n t h l y b a s i s ,  plant  1.1 t o 1 . 1 2 ) .  B.C.  and t h e s o l a r e n e r g y c o l l e c t a b l e by  integral collector.  that  solar-shed  heat l o s s , the  c o n d u c t i o n and r a d i a t i o n )  to n o t i c e  f o r the  s o l a r r a d i a t i o n c a p t u r e by  canopy, t h e i n f i l t r a t i o n  energy c o n t r i b u t i o n )  collection  as the  i n the Vancouver,  I (Tables  supplemental heat requirement  I  output  above and l o c a t e d  i n Appendix  includes  (convection,  the  as w e l l  and management p a r a m e t e r s a r e  day o f e a c h month o f t h e y e a r .  the  Other  DISCUSSION  sample c o m p u t e r  hourly  layer  6.1.  greenhouse d e s c r i b e d area  of 3 millimetres.  of the construction materials  pertinent  a single  f o r the gable greenhouse  i n Table  comparable  6.2  f o r the  to those i n  (Case S t u d y  c o m p a r i s o n between t h e r e s u l t s i n t h e s e  by t h e  tables,  II).  By  i t c a n be  VARIABLES  USED TO CALCULATE HEATING DEMANDS OF A SOLAR-SHED  Construction  Parameters  Length: Width: Height: Roof S l o p e : Orientation: Construction Surface  GREENHOUSE  100 m 10 m 2 m 30° E a s t - W e s t Long  Materials  Properties  Material  Area  U  (m )  (Wm~ K )  2  S o u t h Roof South W a l l North Wall East Wall West W a l l Footing  Single Glass Single Glass Insulated Single Glass Single Glass Insulated  Perimeter  Insulated  Glass  Axis  2  8.83 8.03 0.25 8. 03 8.03 0.67  1155 200 777 49 49 110 220 (m)  s  -1  0.67 (Wm-lK )  0.08 0.08 0.20 0.08 0.08  0.94 0.94 0.94 0.94 0.94 —  —  -1  Properties Thickness: Extraction Coefficient: R e f r a c t i o n Index: Absorptivity to Solar Radiation: E m i s s i v i t y f o r Thermal R a d i a t i o n :  Management  Parameters  Location: Minimum G r e e n h o u s e T e m p e r a t u r e : I n f i l t r a t i o n Rate: P l a n t Canopy A l b e d o :  0.3 cm 0.252 cm" i ron 1.526 0.08 0.94  1  V a n c o u v e r , B.C. M o n t r e a l , P.Q. H a l i f a x , N. S. 15°C 1.5 A i r c h a n g e s p e r h o u r 0.1  MONTHLY AVERAGE HEAT LOSS, SOLAR ENERGY INPUT, SOLAR CONTRIBUTION AND HEATING LOAD IN MJ PER m GREENHOUSE  2  FLOOR AREA AND PERCENT OF THE HEAT LOSS  SUPPLIED BY SOLAR FOR THE SHED GREENHOUSE CASE STUDY IV (MINIMUM  Heat Loss  January  492  February  B.C.  Solar Contribution**  Heating Load  172  116  376  24  387  210  108  279  28  March  407  334  134  273  33  April  277  345  97  180  35  May  161  393  52  109  32  June  81  442  23  58  28  July  44-  432  8  36  18  August  33  429  5  28  15  September  83  340  11  72  13  October  244  261  66  178  27  November  361  146  85  276  24  December  477  122  99  378  21  3047  3626  804  2243  26  YEAR *  Solar Input*  OF  INSIDE TEMPERATURE = 1 5 ° C )  VANCOUVER,  Month  OF  Percent Solar**  S o l a r i n p u t i s t h e s o l a r r a d i a t i o n c a p t u r e d by the p l a n t canopy o n l y and does n o t i n c l u d e s o l a r r a d i a t i o n i n c i d e n t on the i n t e g r a l c o l l e c t o r .  seen  that  the monthly average  greenhouse due  i s h i g h e r than  to the l a r g e r o v e r a l l  shed  the heat  megajoules  per  shed-type per  percent. solar  loss  from  square  the annual  square  metre;  radiation  heat  o r , an  Coupled  megajoules  loss  from  from  the  the gable  heat t r a n s f e r  coefficient On  loss  annual  2818  i s e s t i m a t e d a t 3047  the p l a n t  reduced  the  area w h i l e f o r the  i n c r e a s e i n annual  c a p t u r e d by  of  an  the gable greenhouse i s  heat  with the i n c r e a s e i n the heat  per  shed  greenhouse,  to the gable type.  metre o f f l o o r  type greenhouse i s a l s o 4104  that  s t r u c t u r e as compared  basis,  heat  megajoules  loss of s i x  loss,  canopy i n the  the  shed-  f r o m an a n n u a l v a l u e o f  s q u a r e m e t r e t o 3626 m e g a j o u l e s  per  square metre, r e p r e s e n t i n g a r e d u c t i o n i n the o r d e r o f twelve  percent.  s o l a r energy loss per  passively  remained  virtually  incident  remained upon and  solar  utilized  The  unchanged c a p t u r e d by  gable greenhouse than  contribution or  t o compensate  t h e same a t a b o u t  square metre per y e a r .  contribution is  However, t h e  i n the  reason that  the p l a n t  shed-type  T h e r e f o r e , i t c a n be  requires  less  provided  the  reflective of  ventilation solar  material  the s o l a r  heat  megajoules  the  solar radiation  canopy i n the  d u r i n g t h e warm  concluded  for heating that  than the g a b l e - t y p e  collector  f o r the  i s t h a t more s o l a r  p e r i o d s o f the y e a r w h i l e i t i s not needed purposes.  800  the  the  shed-type  greenhouse  i s c o v e r e d o r r e p l a c e d by  a  d u r i n g t h e summer months t o a l l o w some  radiation  incident  upon t h e i n n e r s u r f a c e o f  the n o r t h w a l l  t o escape  through  the south r o o f of  the  greenhouse. Since, improved has  the p a s s i v e s o l a r  i n the shed-type  i n c r e a s e d , then over  4.2,  i n c r e a s e c a n be  the gable greenhouse.  remains  the shed increased saving. will  be  t o be  eight percent.  Therefore,  the  loss  and  result  contribution  effect  an  two  additional  and  6.4  later  and  are d i r e c t l y  the gable greenhouse case Comparison of Table the f o l l o w i n g  t o be  compared  solar  c o n d i t i o n s on  energy  collector  the h e a t i n g  load  performing  greenhouse u s i n g Montreal  then  f o r the  i n Canada a r e shown i n T a b l e s Halifax,  respectively.  comparable ( T a b l e s 4.3 6.3  6.3  Again,  to those obtained f o r and  t o T a b l e 4.3  4.4). f o r Montreal  points:  average  heat  loss  f o r the shed-type  is  4550 m e g a j o u l e s  per  square metre  t o 4275 m e g a j o u l e s  per  square metre f o r  the g a b l e - t y p e greenhouse o r a p p r o x i m a t e l y increase.  net  section.  Summaries o f t h e r e s u l t s  locations  f o r Montreal  found  in this  g r e e n h o u s e i s e x a m i n e d by  identical  annual  in a significant  of the i n t e g r a l  of c l i m a t i c  H a l i f a x weather d a t a .  these t a b l e s  i f the i n t e g r a l  per  to o f f s e t  investigated  The  megajoules  g r e e n h o u s e c a n p r o v i d e enough h e a t  a n a l y s e s on  i)  as 167  and  within,  of the shed-type  reveals  is  collector  The  The  requirement  loss  solar  heat  seen  been  From T a b l e s 6.2  calculated  square metre a n n u a l l y o r about it  not  greenhouse w h i l e i t s heat  i t s heating load  increased this  c o n t r i b u t i o n has  as  s i x percent  MONTHLY AVERAGE HEAT LOSS, SOLAR ENERGY INPUT, SOLAR CONTRIBUTION AND HEATING LOAD IN MJ PER m GREENHOUSE FLOOR AREA AND PERCENT OF SUPPLIED BY SOLAR FOR THE CASE STUDY IV  OF  HEAT LOSS  SHED GREENHOUSE OF  (MINIMUM INSIDE TEMPERATURE = 15°C) MONTREAL,  Month  THE  2  P.Q.  Heat Loss  Solar Input*  January  968  153  153  815  16  February  799  198  189  610  24  March  648  323  204  444  32  April  361  339  126  235  35  89  391  16  73  18  May  Solar Contribution**  Heating Load  Percent Solar**  June  5  440  1  4  July  0  429  0  0  0  August  0  424  0  0  0  49  332  5  October  272  247  November  495  December  864  September  YEAR  4550  20  44  10  67  205  25  134  114  381  23  108  108  756  13  3518  983  3567  22  S o l a r i n p u tt i s the le s o l a r r a d i a t i o n c a p t u r e d by the p l a n t canopy o n l y and does n o t i n c l u d e s o l a r r a d i a t i o n i n c i d e n t on t h e i n t e g r a l c o l l e c t o r .  ii)  The p l a n t c a n o p y captured on  This  greenhouse has  3518 m e g a j o u l e s p e r s q u a r e  the average  square  i n the shed-type  compared  t o 4045 m e g a j o u l e s p e r  metre f o r t h e p l a n t canopy  r e p r e s e n t s an a n n u a l  capture  metre p e r year  i n the gable-type.  reduction i n solar  radiation  by t h e p l a n t c a n o p y i n t h e o r d e r o f t h i r t e e n  percent. iii)  The p a s s i v e s o l a r three percent  contribution  lower  to the gable-type iv)  When t h e e n e r g y collector requires on  f o r the shed-type  contribution  under  solar  greenhouse the gable-type  results  f o r the  c o n c l u s i o n s as those  shed-type  greenhouse obtained  (Table with  on a p e r c e n t a g e  basis.  performance o f the i n t e g r a l  by s o l a r  fraction  solar  collector  expressed  o f the greenhouse h e a t i n g  i s shown i n T a b l e  6.5 f o r t h e t h r e e  c o n s t r u c t i o n as w e l l as t h e management  the s o l a r - s h e d greenhouse a r e i d e n t i c a l  locations.  The i n t e g r a l  solar  collector,  parameters  f o r the three having  load  locations  study. The  of  than  ( T a b l e 6.4) and t h e g a b l e - t y p e  the monthly average  supplied  the i n t e g r a l  and V a n c o u v e r w e a t h e r d a t a when t h e v a l u e s a r e  expressed  as  compared  basis.  4.4) l e a d s t o s i m i l a r  The  from  n i n e p e r c e n t more h e a t  Comparison o f H a l i f a x  Montreal  when  loss i s  greenhouse,  i s n e g l e c t e d , the shed-type  an a n n u a l  greenhouse  t o the heat  a surface  MONTHLY AVERAGE HEAT LOSS, SOLAR ENERGY INPUT, SOLAR CONTRIBUTION AND HEATING LOAD IN MJ PER m  2  OF  GREENHOUSE FLOOR AREA AND PERCENT OF THE HEAT LOSS SUPPLIED BY SOLAR FOR THE SHED GREENHOUSE OF CASE STUDY IV  (MINIMUM  INSIDE TEMPERATURE = 1 5 ° C )  HALIFAX, N.S. Month  Heat Loss  Solar Input*  Solar C o n t r i b u t i o n **  Heating Load  Percent Solar**  January  684  150  140  544  21  February  627  195  159  468  25  March  572  321  181  391  32  April  390  338  135  255  35  May  228  390  71  157  31  June  97  439  21  76  22  July  32  428  4  28  13  August  25  423  3  22  11  September  72  330  8  64  11  October  218  245  48  170  22  November  37 9  132  85  294  22  December  606  106  106  500  17  3930  3497  961  2969  25  YEAR  *  S o l a r i n p u t i s the s o l a r r a d i a t i o n c a p t u r e d by the p l a n t canopy o n l y and does n o t i n c l u d e s o l a r r a d i a t i o n i n c i d e n t on the i n t e g r a l c o l l e c t o r .  a r e a o f 577 s q u a r e m e t r e s , surface  o f the v e r t i c a l  greenhouse having Air a  i s forced  flow rate  optical  north wall  on t h e  of a solar  1000 s q u a r e m e t r e s o f f l o o r  over both  sides  shed area.  o f the absorber p l a t e a t  properties  of the absorber plate  a r e assumed t o  i n f r a - r e d r a d i a t i o n o f 0.9.  during  i s s i g n i f i c a n t l y higher  for Montreal or Halifax. Vancouver,  6.5  indicates  t h e w i n t e r months t h e s o l a r c o l l e c t o r  contribution  the s o l a r  f o r Vancouver  F o r example,  collector contribution  i s 97 m e g a j o u l e s  square metre o f greenhouse f l o o r area w h i l e  and  Halifax,  i t i s only  high contribution that  higher  vertical  The  collectors receive the winter  be a t t r i b u t e d  The  to the  more r a d i a t i o n a t  period.  low s o l a r e n e r g y c o l l e c t i o n by t h e i n t e g r a l  collector  f o r M o n t r e a l and H a l i f a x ,  h i g h greenhouse h e a t i n g  loads during  year, r e s u l t e d  i n a very  small  f r o m November  to February^inclusive.  f r o m as low a s 4 p e r c e n t percent  f o r Montreal  50 m e g a j o u l e s p e r s q u a r e m e t r e .  f o r Vancouver could  l a t i t u d e s during  than  i n January f o r  per  fact  The  t o s o l a r r a d i a t i o n and e m i s s i v i t y  E