International Construction Specialty Conference of the Canadian Society for Civil Engineering (ICSC) (5th : 2015)

The effect of shading design and materials on building energy demand Haghighi, Nasim; Asadi, Somayeh; Babaizadeh, Hamed Jun 30, 2015

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5th International/11th Construction Specialty Conference 5e International/11e Conférence spécialisée sur la construction    Vancouver, British Columbia June 8 to June 10, 2015 / 8 juin au 10 juin 2015   THE EFFECT OF SHADING DESIGN AND MATERIALS ON BUILDING ENERGY DEMAND Nasim Haghighi1, Somayeh Asadi2,4, and Hamed Babaizadeh3  1 Former graduate student, Texas A&M University –Kingsville 2 Assistant Professor, Pennsylvania State University,  3 Stantec Consulting Inc., 4asadi@engr.psu.edu Abstract: Building sector in most countries around the world requires large amounts of heating and cooling energy. Indeed, building cooling loads due to solar gains are responsible for approximately half of global cooling load. In addition, windows are considered as one of the important sources of energy loss in buildings. In order to minimize this loss, shading devices can be installed in the exterior part of the window to reduce solar heat. The objective of this study is to investigate the simultaneous effect of glazing, shading materials, and configuration of shading devices on total building energy consumption in different climate regions in the United States. To achieve this objective, a typical residential building was selected to assess the effect of the aforementioned parameters on total energy consumption in five main climate regions. A series of simulations were conducted using EnergyPlus simulation program to quantify energy consumption in each scenario and determine the most energy efficient glazing and shading materials as well as configuration of the shading device. Different types of window glazing (including clear, Low-Iron, Ref-B tint, Low-E clear and Low-E tint with 6 mm thickness) as well as different materials for shading devices (including PVC, aluminum and wood) were considered in this study. Moreover, the effect of five different shading device configurations, including horizontal and oriented overhang, vertical fin and combination of them were investigated. Results showed installing vertical fins and horizontal overhang shading devices in buildings located in Miami and Atlanta do not have a significant effect on annual energy consumption. However, combining these two overhang shading configurations will reduce energy consumption. In addition to shading configurations, it was found that Ref-B tint glazing material along with wood shading material reduced annual energy consumption by approximately 11.6% in Miami. However in Atlanta, total energy consumption was reduced by approximately 7% in the case of using Low-E tint glazing material along with wood shading material. No significant decrease in energy consumption was observed in cold climates. 1 INTRODUCTION The total energy consumption in U.S. buildings has increased in recent years. Building energy consumption had increased by 48% for the period between 1980 and 2009.  In 2009, residential buildings consumed 20.99 quadrillion Btu energy which is equivalent to 54% of building sector energy consumption as well as 22% of total primary energy consumption in the United States (Kelso 2012). One of the major sources of energy consumption in buildings is associated with space cooling and heating systems. In the United States, heating and cooling energy consumption is equal to 43% and 52% of the total energy consumption in residential and commercial sector, respectively. Building sector in most countries around 077-1 the world requires large amount of heating and cooling energy demand. Indeed, cooling load due to solar gains is responsible for approximately half of the global cooling load in both residential and commercial buildings. According to Residential Energy Consumption Survey (RECS), heating and cooling energy consumption was reduced by 10% in the U.S. residential buildings from 1993 to 2009 (2009). To continue this reduction trend, different parameters such as more efficient equipment, better insulation materials and more efficient windows can be used in buildings.   Windows are considered as one of the main sources of energy loss in buildings. Windows are mostly used as the architectural devices that connect the interior space to outdoors. Therefore, they absorb solar radiation and transfer the captivated heat inside the buildings. The three sources of solar radiation on exterior surface result from sun direct radiation, sky diffuse radiation as well as buildings and adjacent surface reflected radiation. Exterior shading devices are one of the building elements that can restrict the direct solar radiation and decrease the effect of the reflected and diffuse radiation(Stack, Goulding, and Lewis 2000). The main advantage of using shading devices is to restrict solar radiation (Stack, Goulding, and Lewis 2000). Effective shading devices should control solar radiation before heating up the fenestration and should provide large shading area for summer, while allow for maximum solar radiation absorption in winter. Recently, it has been found exterior shading devices can reduce energy consumption and improve thermal comfort of buildings. Moreover, they provide a great view for the occupants by reducing glare (Norbert Lechner 2008). Several studies have been investigated the relation between shading devices and energy consumption. Peebles(Peebles 1940) conducted one of the very first works to investigate the effect of shading devices on energy consumption through an experimental study. It was found that shading devices with different colors can reduce building energy consumption. The results of the study showed that light color shading devices decrease heat gain by about 55% and 40% in the summer and winter, respectively.  In another study conducted by Emery et al.(Emery et al. 1981), they found that the performance of shading systems in reducing building energy consumption significantly depends on climate condition. According to this study, the effect of climate on the performance of shading device systems was investigated for three cities in the United States and it was found that fixed overhangs and fins had the most reduction in energy consumption. In a similar study, Harkness (Harkness 1988) investigated the effects of various parameters including window areas and sunscreen projection on cooling energy reduction in Australian buildings. He found that use of single pane clear glass with exterior precast concrete overhangs and fins decreased the cooling energy loads by 50%. In another study conducted by Tzempelikos and Roy (Tzempelikos and Roy 2004), the effect of fixed and movable shading devices on thermal comfort and visualization was investigated. An office building with a large glass area in Montreal was selected as a case study in this work. It was found shading properties and location have significant effects on heating and cooling loads as well as thermal comfort. The simulation results indicated that exterior shading devices with small transmittance and high reflectance can reduce cooling loads by 60%. Kim and Kim(J. Kim and Kim 2010) conducted a series of simulation to compare exterior and interior shading devices in terms of energy performance and view. It was found that exterior shading devices reduce cooling and heating loads by 20% and 12%, respectively, and provide a better view compared to interior shading devices. Kim et al.(G. Kim et al. 2012) compared various exterior shading devices in terms of heating and cooling energy saving for residential building in South Korea. According to this study, the great impact on energy reduction occurred by changing the slat angle of shading devices. The slat angle range was between 0° to 60°. Smaller window area was covered with shading devices when the slat angle was reduced. Therefore, the occupant’s view and energy consumption were improved. The objective of this study is to investigate simultaneous effects of glazing and shading materials in addition to the configuration of the shading devices on total building energy consumption in different climate regions in the United States. To achieve this objective, a typical residential building was selected in this study to assess the effect of these parameters on total energy consumption in five climate regions in the United States. A series of simulations were conducted using EnergyPlus simulation software to quantify energy consumption in each scenario and determine the most energy efficient glazing and shading materials besides configurations of the shading devices. Different types of window glazing materials (including clear, Low-Iron, Ref-B tint, Low-E clear and Low-E tint with 6 mm thickness) along 077-2 with different materials for shading devices (including PVC, aluminum and wood) were considered in this study. Moreover, the effect of five different configurations of shading devices, including horizontal and oriented overhang, vertical fin and combination of these configurations were studied in this paper.  2  METHODOLOGY The objective of this study is to investigate the effect of various shading devices and glazing materials on residential building energy consumption in five climatic zones in the United States. Five different types of shading devices, three different shading materials and five glazing types were studied. Different scenarios were compared together to find out the most efficient combination for each studied climate zone.  A detailed flowchart for simulation steps is shown in Figure 1.  Variables  Glazing Materials Shading Properties Shading Materials Weather Data  Building model developed in Ecotect Building Geometry  EnergyPlus Input Data   EnergyPlus Output Data Data processing and comparing  Figure 1: Framework of the simulation model. 2.1 Selection of Representative Locations Energy consumption varies significantly from building to building located in different climate regions. Climate is  one of the most important factors in selecting effective exterior shading devices in terms of energy savings (Khezri 2012). According to Energy Information Administration (2005), the climate regions in the United States categorized into 5 main categories (see Figure 2) based on the last 30-year average heating degree-days (HDD) and cooling degree-days (CDD). The geographical information of the representative cities are summarized in Table 1.  Figure 2: Energy Information Administration climate zones with cities (EIA 2005).  077-3 Table 1: Building location and geometry Climate Zone Cities Weather Condition Latitude Longitude Summer Altitude (degrees) 5 FL-Miami Hot-Humid 25.78 80.3 69.25 4 GA-Atlanta Mixed-Humid 33.66 84.42 63.18 3 WA-Seattle Marine 47.43 121.8 51.13 2 IL-Chicago Cold 41.97 87.89 56.03 1 MN-Duluth Very cold 46.82 92.18 51.66 2.2 Building model A typical residential building (see Figure 3) was selected in this study to evaluate the effect of various shading designs and materials on total energy consumption in different climate regions in the U.S. The studied building was a one-story detached house with a height of 3.2 m and a total floor area of 130 m2. The total window to wall ratio is 18.87 where the height and width of the windows are equal to 1.4 m and 1.2 m. The Ecotect (version 5.6) was used to build the building's geometry and then it was imported in EnergyPlus for energy consumption simulation. All envelop properties, schedules and equipment (lighting system, HVAC system, etc.) were defined in EnergyPlus. The inside temperature was set to 20 and 24°C in winter and summer, respectively.  Figure 3: Typical Residential Building, (a) Floor Plan; (b) and (c) 3D model. 2.3 Glazing type  Building energy consumption can be affected greatly by glazing properties and shading configurations. In this study, the effect of five different types of glazing as well as five shading configurations considering shading depth and shading materials on building energy consumption were studied. The five studied glazing systems were Low Iron, Ref-B tint, Low-E clear, and Low-E tint with 6 mm thickness. To evaluate the performance of these glazing systems, a control case with no shading devices was simulated for each climate zone to identify the best-performing glazing type which served as the control case to evaluate shading performance. 2.4 Exterior solar shading devices 2.4.1 Shading depth  The depths of shading devices are different in each climate regions depending on the solar altitude angle. Solar altitude is the angle between the sun’s ray and the projection of that ray on a horizontal surface. It is a function of a location’s longitude and latitude. One important design principle for exterior shading 077-4 The energy consumption with shading 4 along with wood material and Ref-B tint as an efficient glazing material was 13 MWh, which was a reduction in the annual energy consumption by about 11.6%. Shading device 4 increases the shade area of window and restricted excessive solar beams and consequently the cooling energy consumption was reduced. In addition, heating energy demand in Miami is not too much due to weather condition, so it did not have a significant impact on the annual energy consumption. 12.7013.1013.5013.9014.3014.70WoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlEnergy Consumption (MWh)Heating CoolingClear glasswithout shading Shading 1      shading 2          Shading 3        Shading 4        Shading 5 Figure 9: Annual energy consumption of various variables in Miami 3.2.2 Mixed-humid climate zone Atlanta was selected to simulate the effect of exterior shading devices in mixed-humid climate zone. As Figure 10 shows, the total annual energy consumption in a building having shading device 4 along with wood as a shading material and Low-E tint as a glazing material is 11.95 MWh which reduced the annual total energy consumption by about 7.1% in comparison with clear glass case with no shading.  5.506.507.508.509.5010.5011.5012.50WoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlEnergy Consumption (MWh)Heating CoolingClear glasswithout shading Shading 1         shading 2         Shading 3        Shading 4       Shading 5 Figure 10: Annual energy consumption of various variables in Atlanta 3.2.3 Marine climate zone For marine climate zone, Seattle was selected as a representative location. According to Figure 11, the total annual heating and cooling energy loads in a building with shading 3 and Low-E clear as a glazing material is 10.1 and 2.1 MWh, respectively and for clear glass case with no shading is 9.98 and 2.77 MWh. Therefore, it was found that replacing clear glass with Low-E clear glass result in 4.2% reduction in energy consumption in Seattle. Also, the energy consumption is not affected much by shading materials in this climate zone. 077-8 Clear glasswithout shading9.09.510.010.511.011.512.012.5WoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlEnergy Consumption (MWh)heating coolingShading 1        shading 2            Shading 3        Shading 4            Shading 5 Figure 11: Annual energy consumption of various variables in Seattle 3.2.4 Cold and very cold climate zone As Figure 12 shows, in Chicago and Duluth (climate zone cold and very cold), the best performance was achieved in Duluth for a building having shading 2 along with Low-E clear as a glazing material. For a building with Low-E clear glass in Duluth, heating and cooling energy consumption were 21.6 and 2.1 MWh, respectively and for the control case were 21.88 and 2.55 MWh. In Chicago for shadings 3 and 4 with Low-E tint as glazing material, heating and cooling energy consumption respectively were 13.93 and 4.3 MWh and for clear glass case with no shading were 13.85 and 5.08 MWh. In comparison with control case, total energy consumption was reduced by about 3.69%. As shown in Figure 12, shading device does not have a significant impact on energy consumption in cold climates.  91113151719212325without shadingshading 1shading 2shading 3shading 4shading 5without shadingshading 1shading 2shading 3shading 4shading 5Energy Consumption (MWh)Chicago                                       Duluth Figure 12: Total energy consumption of cold and very cold climate zones 3.3 Shading properties guideline A numerical simulation was conducted to study the impact of exterior shading types, shading and glazing materials on annual energy consumption. After identifying the best performing glazing types for all locations, a series of simulations were conducted to study the impact of different shading types and shading materials. Table 3 summarizes best scenarios among 15 cases with different combinations of shading devices and shading materials in each climate zone.   077-9 Table 3: Efficient scenarios and total energy consumption in each climate region City Energy consumption (MWh) %Decrease in energy Glazing Material Shading Type Shading Material Orientation Miami 13.06 11.6% Ref B Tint Shading 4 Wood All Side Atlanta 11.95 7.1% Low E Tint Shading 4 Wood All Side Seattle 12.21 4.2% Low E Clear Shading 3 N/A All Side Chicago 18.23 3.7% Low E Tint Shadings 3 and 4 N/A All Side Duluth 23.82 2.5% Low E Clear Shading 2 N/A All Side 4 CONCLUSIONS This study investigated the impact of various shading devices and glazing materials on total energy consumption of a typical residential building in different U.S. climate regions. In this study, five different shading devices (horizontal and oriented overhang, vertical fins, and combination of these two), five glazing materials (clear, low-iron, Ref-B tint, Low-E clear, and Low-E tint with 6 mm thickness) and three different shading materials (PVC, aluminum and wood) were considered as potential fenestration elements. In all climate regions, exterior shading devices reduced cooling energy consumption compared to the buildings without shading. The results of this study can be used as a guideline to select the most efficient shading types for various U.S. climate zones. It was concluded in hot climate zones, shading properties and materials play a key role in cooling energy consumption due to restricting the solar beams. In cold and very cold climate regions, installing exterior shading devices can reduce the cooling demand in summer and increase heating demand in winter. Therefore, no significant reduction in total energy consumption may be resulted. References 2005. “AIA Climate Zones — RECS 1978-2005” U.S. Energy Information Administration (EIA). http://www.eia.gov/. 2009. “2009 RECS Survay Data” U.S. Energy Information Administration (EIA). http://www.eia.gov/. Emery, A. F., B.R. Johnson, D.R. Heerwagen, and C.J. Kippenhan. 1981. “Assessing the Benefit-Costs of Employing Alternative Shading Devices to Reduce Cooling Loads for Three Climates.” In International Passive and Hybrid Cooling Conference, 417–21. Harkness, E.L. 1988. “The Energy and Thermal Comfort Advantages of Shading Windows.” Australian Refrigeration, Air Conditioning and Heating 42 (10): 33–41. Kelso, J. 2012. “2011 Buildings Energy Data Book.” Department of Energy. Khezri, NA. 2012. “Comparative Analysis of PV Shading Devices for Energy Performance and Daylight.”  Kim, Gon, Hong Soo Lim, Tae Sub Lim, Laura Schaefer, and Jeong Tai Kim. 2012. “Comparative Advantage of an Exterior Shading Device in Thermal Performance for Residential Buildings.” Energy and Buildings 46 (March). Elsevier B.V. 105–11.  Kim, JT, and Gon Kim. 2010. “Advanced External Shading Device to Maximize Visual and View Performance.” Indoor and Built Environment, no. October: 49–74.  Norbert Lechner. 2008. Heating, Cooling, Lighting: Sustainable Design Methods for Architects. Peebles, J.C. 1940. Final Report to the Window Shade Institute. Rungta, Shaily, and I Vipul Singh. 2011. “Design Guide: Horizontal Shading Devices and Light Shelves”, no. 3. Stack, Austin, John Goulding, and JO Lewis. 2000. “Shading System; Solar Shading for the European Climates.”  Tzempelikos, Athanassios, and Martin Roy. 2004. “A Simulation Design Study for the Façade Renovation of an Office Building.” The Canadian Solar Buildings.   077-10  5th International/11th Construction Specialty Conference 5e International/11e Conférence spécialisée sur la construction    Vancouver, British Columbia June 8 to June 10, 2015 / 8 juin au 10 juin 2015   THE EFFECT OF SHADING DESIGN AND MATERIALS ON BUILDING ENERGY DEMAND Nasim Haghighi1, Somayeh Asadi2,4, and Hamed Babaizadeh3  1 Former graduate student, Texas A&M University –Kingsville 2 Assistant Professor, Pennsylvania State University,  3 Stantec Consulting Inc., 4asadi@engr.psu.edu Abstract: Building sector in most countries around the world requires large amounts of heating and cooling energy. Indeed, building cooling loads due to solar gains are responsible for approximately half of global cooling load. In addition, windows are considered as one of the important sources of energy loss in buildings. In order to minimize this loss, shading devices can be installed in the exterior part of the window to reduce solar heat. The objective of this study is to investigate the simultaneous effect of glazing, shading materials, and configuration of shading devices on total building energy consumption in different climate regions in the United States. To achieve this objective, a typical residential building was selected to assess the effect of the aforementioned parameters on total energy consumption in five main climate regions. A series of simulations were conducted using EnergyPlus simulation program to quantify energy consumption in each scenario and determine the most energy efficient glazing and shading materials as well as configuration of the shading device. Different types of window glazing (including clear, Low-Iron, Ref-B tint, Low-E clear and Low-E tint with 6 mm thickness) as well as different materials for shading devices (including PVC, aluminum and wood) were considered in this study. Moreover, the effect of five different shading device configurations, including horizontal and oriented overhang, vertical fin and combination of them were investigated. Results showed installing vertical fins and horizontal overhang shading devices in buildings located in Miami and Atlanta do not have a significant effect on annual energy consumption. However, combining these two overhang shading configurations will reduce energy consumption. In addition to shading configurations, it was found that Ref-B tint glazing material along with wood shading material reduced annual energy consumption by approximately 11.6% in Miami. However in Atlanta, total energy consumption was reduced by approximately 7% in the case of using Low-E tint glazing material along with wood shading material. No significant decrease in energy consumption was observed in cold climates. 1 INTRODUCTION The total energy consumption in U.S. buildings has increased in recent years. Building energy consumption had increased by 48% for the period between 1980 and 2009.  In 2009, residential buildings consumed 20.99 quadrillion Btu energy which is equivalent to 54% of building sector energy consumption as well as 22% of total primary energy consumption in the United States (Kelso 2012). One of the major sources of energy consumption in buildings is associated with space cooling and heating systems. In the United States, heating and cooling energy consumption is equal to 43% and 52% of the total energy consumption in residential and commercial sector, respectively. Building sector in most countries around 077-1 the world requires large amount of heating and cooling energy demand. Indeed, cooling load due to solar gains is responsible for approximately half of the global cooling load in both residential and commercial buildings. According to Residential Energy Consumption Survey (RECS), heating and cooling energy consumption was reduced by 10% in the U.S. residential buildings from 1993 to 2009 (2009). To continue this reduction trend, different parameters such as more efficient equipment, better insulation materials and more efficient windows can be used in buildings.   Windows are considered as one of the main sources of energy loss in buildings. Windows are mostly used as the architectural devices that connect the interior space to outdoors. Therefore, they absorb solar radiation and transfer the captivated heat inside the buildings. The three sources of solar radiation on exterior surface result from sun direct radiation, sky diffuse radiation as well as buildings and adjacent surface reflected radiation. Exterior shading devices are one of the building elements that can restrict the direct solar radiation and decrease the effect of the reflected and diffuse radiation(Stack, Goulding, and Lewis 2000). The main advantage of using shading devices is to restrict solar radiation (Stack, Goulding, and Lewis 2000). Effective shading devices should control solar radiation before heating up the fenestration and should provide large shading area for summer, while allow for maximum solar radiation absorption in winter. Recently, it has been found exterior shading devices can reduce energy consumption and improve thermal comfort of buildings. Moreover, they provide a great view for the occupants by reducing glare (Norbert Lechner 2008). Several studies have been investigated the relation between shading devices and energy consumption. Peebles(Peebles 1940) conducted one of the very first works to investigate the effect of shading devices on energy consumption through an experimental study. It was found that shading devices with different colors can reduce building energy consumption. The results of the study showed that light color shading devices decrease heat gain by about 55% and 40% in the summer and winter, respectively.  In another study conducted by Emery et al.(Emery et al. 1981), they found that the performance of shading systems in reducing building energy consumption significantly depends on climate condition. According to this study, the effect of climate on the performance of shading device systems was investigated for three cities in the United States and it was found that fixed overhangs and fins had the most reduction in energy consumption. In a similar study, Harkness (Harkness 1988) investigated the effects of various parameters including window areas and sunscreen projection on cooling energy reduction in Australian buildings. He found that use of single pane clear glass with exterior precast concrete overhangs and fins decreased the cooling energy loads by 50%. In another study conducted by Tzempelikos and Roy (Tzempelikos and Roy 2004), the effect of fixed and movable shading devices on thermal comfort and visualization was investigated. An office building with a large glass area in Montreal was selected as a case study in this work. It was found shading properties and location have significant effects on heating and cooling loads as well as thermal comfort. The simulation results indicated that exterior shading devices with small transmittance and high reflectance can reduce cooling loads by 60%. Kim and Kim(J. Kim and Kim 2010) conducted a series of simulation to compare exterior and interior shading devices in terms of energy performance and view. It was found that exterior shading devices reduce cooling and heating loads by 20% and 12%, respectively, and provide a better view compared to interior shading devices. Kim et al.(G. Kim et al. 2012) compared various exterior shading devices in terms of heating and cooling energy saving for residential building in South Korea. According to this study, the great impact on energy reduction occurred by changing the slat angle of shading devices. The slat angle range was between 0° to 60°. Smaller window area was covered with shading devices when the slat angle was reduced. Therefore, the occupant’s view and energy consumption were improved. The objective of this study is to investigate simultaneous effects of glazing and shading materials in addition to the configuration of the shading devices on total building energy consumption in different climate regions in the United States. To achieve this objective, a typical residential building was selected in this study to assess the effect of these parameters on total energy consumption in five climate regions in the United States. A series of simulations were conducted using EnergyPlus simulation software to quantify energy consumption in each scenario and determine the most energy efficient glazing and shading materials besides configurations of the shading devices. Different types of window glazing materials (including clear, Low-Iron, Ref-B tint, Low-E clear and Low-E tint with 6 mm thickness) along 077-2 with different materials for shading devices (including PVC, aluminum and wood) were considered in this study. Moreover, the effect of five different configurations of shading devices, including horizontal and oriented overhang, vertical fin and combination of these configurations were studied in this paper.  2  METHODOLOGY The objective of this study is to investigate the effect of various shading devices and glazing materials on residential building energy consumption in five climatic zones in the United States. Five different types of shading devices, three different shading materials and five glazing types were studied. Different scenarios were compared together to find out the most efficient combination for each studied climate zone.  A detailed flowchart for simulation steps is shown in Figure 1.  Variables  Glazing Materials Shading Properties Shading Materials Weather Data  Building model developed in Ecotect Building Geometry  EnergyPlus Input Data   EnergyPlus Output Data Data processing and comparing  Figure 1: Framework of the simulation model. 2.1 Selection of Representative Locations Energy consumption varies significantly from building to building located in different climate regions. Climate is  one of the most important factors in selecting effective exterior shading devices in terms of energy savings (Khezri 2012). According to Energy Information Administration (2005), the climate regions in the United States categorized into 5 main categories (see Figure 2) based on the last 30-year average heating degree-days (HDD) and cooling degree-days (CDD). The geographical information of the representative cities are summarized in Table 1.  Figure 2: Energy Information Administration climate zones with cities (EIA 2005).  077-3 Table 1: Building location and geometry Climate Zone Cities Weather Condition Latitude Longitude Summer Altitude (degrees) 5 FL-Miami Hot-Humid 25.78 80.3 69.25 4 GA-Atlanta Mixed-Humid 33.66 84.42 63.18 3 WA-Seattle Marine 47.43 121.8 51.13 2 IL-Chicago Cold 41.97 87.89 56.03 1 MN-Duluth Very cold 46.82 92.18 51.66 2.2 Building model A typical residential building (see Figure 3) was selected in this study to evaluate the effect of various shading designs and materials on total energy consumption in different climate regions in the U.S. The studied building was a one-story detached house with a height of 3.2 m and a total floor area of 130 m2. The total window to wall ratio is 18.87 where the height and width of the windows are equal to 1.4 m and 1.2 m. The Ecotect (version 5.6) was used to build the building's geometry and then it was imported in EnergyPlus for energy consumption simulation. All envelop properties, schedules and equipment (lighting system, HVAC system, etc.) were defined in EnergyPlus. The inside temperature was set to 20 and 24°C in winter and summer, respectively.  Figure 3: Typical Residential Building, (a) Floor Plan; (b) and (c) 3D model. 2.3 Glazing type  Building energy consumption can be affected greatly by glazing properties and shading configurations. In this study, the effect of five different types of glazing as well as five shading configurations considering shading depth and shading materials on building energy consumption were studied. The five studied glazing systems were Low Iron, Ref-B tint, Low-E clear, and Low-E tint with 6 mm thickness. To evaluate the performance of these glazing systems, a control case with no shading devices was simulated for each climate zone to identify the best-performing glazing type which served as the control case to evaluate shading performance. 2.4 Exterior solar shading devices 2.4.1 Shading depth  The depths of shading devices are different in each climate regions depending on the solar altitude angle. Solar altitude is the angle between the sun’s ray and the projection of that ray on a horizontal surface. It is a function of a location’s longitude and latitude. One important design principle for exterior shading 077-4 The energy consumption with shading 4 along with wood material and Ref-B tint as an efficient glazing material was 13 MWh, which was a reduction in the annual energy consumption by about 11.6%. Shading device 4 increases the shade area of window and restricted excessive solar beams and consequently the cooling energy consumption was reduced. In addition, heating energy demand in Miami is not too much due to weather condition, so it did not have a significant impact on the annual energy consumption. 12.7013.1013.5013.9014.3014.70WoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlEnergy Consumption (MWh)Heating CoolingClear glasswithout shading Shading 1      shading 2          Shading 3        Shading 4        Shading 5 Figure 9: Annual energy consumption of various variables in Miami 3.2.2 Mixed-humid climate zone Atlanta was selected to simulate the effect of exterior shading devices in mixed-humid climate zone. As Figure 10 shows, the total annual energy consumption in a building having shading device 4 along with wood as a shading material and Low-E tint as a glazing material is 11.95 MWh which reduced the annual total energy consumption by about 7.1% in comparison with clear glass case with no shading.  5.506.507.508.509.5010.5011.5012.50WoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlEnergy Consumption (MWh)Heating CoolingClear glasswithout shading Shading 1         shading 2         Shading 3        Shading 4       Shading 5 Figure 10: Annual energy consumption of various variables in Atlanta 3.2.3 Marine climate zone For marine climate zone, Seattle was selected as a representative location. According to Figure 11, the total annual heating and cooling energy loads in a building with shading 3 and Low-E clear as a glazing material is 10.1 and 2.1 MWh, respectively and for clear glass case with no shading is 9.98 and 2.77 MWh. Therefore, it was found that replacing clear glass with Low-E clear glass result in 4.2% reduction in energy consumption in Seattle. Also, the energy consumption is not affected much by shading materials in this climate zone. 077-8 Clear glasswithout shading9.09.510.010.511.011.512.012.5WoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlEnergy Consumption (MWh)heating coolingShading 1        shading 2            Shading 3        Shading 4            Shading 5 Figure 11: Annual energy consumption of various variables in Seattle 3.2.4 Cold and very cold climate zone As Figure 12 shows, in Chicago and Duluth (climate zone cold and very cold), the best performance was achieved in Duluth for a building having shading 2 along with Low-E clear as a glazing material. For a building with Low-E clear glass in Duluth, heating and cooling energy consumption were 21.6 and 2.1 MWh, respectively and for the control case were 21.88 and 2.55 MWh. In Chicago for shadings 3 and 4 with Low-E tint as glazing material, heating and cooling energy consumption respectively were 13.93 and 4.3 MWh and for clear glass case with no shading were 13.85 and 5.08 MWh. In comparison with control case, total energy consumption was reduced by about 3.69%. As shown in Figure 12, shading device does not have a significant impact on energy consumption in cold climates.  91113151719212325without shadingshading 1shading 2shading 3shading 4shading 5without shadingshading 1shading 2shading 3shading 4shading 5Energy Consumption (MWh)Chicago                                       Duluth Figure 12: Total energy consumption of cold and very cold climate zones 3.3 Shading properties guideline A numerical simulation was conducted to study the impact of exterior shading types, shading and glazing materials on annual energy consumption. After identifying the best performing glazing types for all locations, a series of simulations were conducted to study the impact of different shading types and shading materials. Table 3 summarizes best scenarios among 15 cases with different combinations of shading devices and shading materials in each climate zone.   077-9 Table 3: Efficient scenarios and total energy consumption in each climate region City Energy consumption (MWh) %Decrease in energy Glazing Material Shading Type Shading Material Orientation Miami 13.06 11.6% Ref B Tint Shading 4 Wood All Side Atlanta 11.95 7.1% Low E Tint Shading 4 Wood All Side Seattle 12.21 4.2% Low E Clear Shading 3 N/A All Side Chicago 18.23 3.7% Low E Tint Shadings 3 and 4 N/A All Side Duluth 23.82 2.5% Low E Clear Shading 2 N/A All Side 4 CONCLUSIONS This study investigated the impact of various shading devices and glazing materials on total energy consumption of a typical residential building in different U.S. climate regions. In this study, five different shading devices (horizontal and oriented overhang, vertical fins, and combination of these two), five glazing materials (clear, low-iron, Ref-B tint, Low-E clear, and Low-E tint with 6 mm thickness) and three different shading materials (PVC, aluminum and wood) were considered as potential fenestration elements. In all climate regions, exterior shading devices reduced cooling energy consumption compared to the buildings without shading. The results of this study can be used as a guideline to select the most efficient shading types for various U.S. climate zones. It was concluded in hot climate zones, shading properties and materials play a key role in cooling energy consumption due to restricting the solar beams. In cold and very cold climate regions, installing exterior shading devices can reduce the cooling demand in summer and increase heating demand in winter. Therefore, no significant reduction in total energy consumption may be resulted. References 2005. “AIA Climate Zones — RECS 1978-2005” U.S. Energy Information Administration (EIA). http://www.eia.gov/. 2009. “2009 RECS Survay Data” U.S. Energy Information Administration (EIA). http://www.eia.gov/. Emery, A. F., B.R. Johnson, D.R. Heerwagen, and C.J. Kippenhan. 1981. “Assessing the Benefit-Costs of Employing Alternative Shading Devices to Reduce Cooling Loads for Three Climates.” In International Passive and Hybrid Cooling Conference, 417–21. Harkness, E.L. 1988. “The Energy and Thermal Comfort Advantages of Shading Windows.” Australian Refrigeration, Air Conditioning and Heating 42 (10): 33–41. Kelso, J. 2012. “2011 Buildings Energy Data Book.” Department of Energy. Khezri, NA. 2012. “Comparative Analysis of PV Shading Devices for Energy Performance and Daylight.”  Kim, Gon, Hong Soo Lim, Tae Sub Lim, Laura Schaefer, and Jeong Tai Kim. 2012. “Comparative Advantage of an Exterior Shading Device in Thermal Performance for Residential Buildings.” Energy and Buildings 46 (March). Elsevier B.V. 105–11.  Kim, JT, and Gon Kim. 2010. “Advanced External Shading Device to Maximize Visual and View Performance.” Indoor and Built Environment, no. October: 49–74.  Norbert Lechner. 2008. Heating, Cooling, Lighting: Sustainable Design Methods for Architects. Peebles, J.C. 1940. Final Report to the Window Shade Institute. Rungta, Shaily, and I Vipul Singh. 2011. “Design Guide: Horizontal Shading Devices and Light Shelves”, no. 3. Stack, Austin, John Goulding, and JO Lewis. 2000. “Shading System; Solar Shading for the European Climates.”  Tzempelikos, Athanassios, and Martin Roy. 2004. “A Simulation Design Study for the Façade Renovation of an Office Building.” The Canadian Solar Buildings.   077-10  THE EFFECT OF SHADING DESIGN AND MATERIALS ON BUILDING ENERGY DEMAND Nasim Haghighi, Somayeh Asadi, and Hamed Babaizadeh  Problem statement q  The combined effect of external shading device configuration, shading material and glazing material are not well understood.  q  Comparative study considering shading device materials, shapes of the shading devices, glazing materials and climate characteristics for identification of the efficient devices has not been performed. 2 Objectives q  To investigate the effect of  q  Shading types  q  Shading materials q  glazing materials  q  To obtain the specific shading guideline based on energy consumption which designers can select energy efficient shading devices with consideration of climate characteristics.  3 Methodology EnergyPlus (version 7.2) simulation program is used to examine the heating and cooling energy consumption in different climate zones in United States.   4 Variables 	  Glazing Materials	  Shading Properties	  Shading Materials	  Weather Data	  Building model developed in Ecotect	  Building Geometry	  	  EnergyPlus Input Data	  	  	   	  EnergyPlus Output Data	  Data processing and comparing	  Methodology 5 ASHRAE	  90.1-­‐2004	  climate	  zones	  	  Climate and Representative Locations        Miami Atlanta Seattle Chicago Duluth Methodology q  Building Model   6 Methodology q  Building Model  7 Parameters Value Design Temperature Cooling set point 24ºc Heating set point 20ºc People 4 persons Use schedule All day used Location and weather data FL-Miami GA-Atlanta WA-Seattle IL-Chicago MN-Duluth HVAC system Ideal System Building area 130 m2 Window high 1.4 m Window Area 6.72 m2 Floor-to-ceiling 3.2 m Building construction Wood Roof Roofing wood shingles Floor Acoustic Tile Wall Section Exterior Façade Insulation Plywood Interior Surface Methodology q  Studied Glazing Materials   8 Glass Type Thickness (mm) Conductivity (W/m.k) Solar Transmittance Clear 6 0.9 0.775 Low-E Clear 6 0.9 0.6 Low-E Tint 6 0.9 0.36 Low-E Iron 6 0.9 0.889 Ref Tint 6 0.9 0.1 Methodology q  External Solar Shading Devices Depth Shading  depth=  (window  height  ×  cos  (solar  azimuth-­‐window  azimuth))  /  tan  (solar  altitude)  9 (Rungta and Singh, 2011) Methodology q  External Solar Shading Devices Type      10 Shading 1 Shading 2 Shading 3 Shading 4 Shading 5 Methodology q  External Solar Shading Devices Material      11 Type Roughness Thickness (m) Conductivity (W/m.K) Wood Medium Smooth 0.1016 0.15 PVC Medium Smooth 0.1 0.2 Aluminum Rough 0.01 230 Methodology q  Parametric study     12  	  Input Data	  	   	  Weather Data	  	   	  Building Geometry	  	  EnergyPlus Results	  Annual Energy Consumption	  = EC	  Annual Energy Consumption	  = EG	  Percent Annual Energy Consumption Reduction	  𝐸=100×​​(𝐸↓𝐶 − ​𝐸↓𝐺 )/​𝐸↓𝐶  	  Find Efficient Glazing Material for Each climate 	   	  Clear	  	   	  Ref-B Tint	  	  	   	  Low-E Tint	  	  	   	  Low-E Iron	  	  	   	  Low-E 	  Clear	  	  	  Windows Glazing Materials	  Methodology q  Parametric study     13  	  Input Data	  	   	  Weather Data	  	   	  Building Geometry	  	  Annual Energy Consumption	  = EV	  EnergyPlus Results	   	   	   	  Shading Materials	  	  	   	  Efficient Glazing Material	  	  	   	   	   	   	   	  Shading Forms	  	  	  Design Variables 	  Percent Annual Energy Consumption Reduction	  𝐸=100×​​(𝐸↓𝑐 − ​𝐸↓𝑉 )/​𝐸↓𝑐  	  Find Efficient Shading Forms and Shading Material with Efficient Window for Each Climate	  Results and discussion q  Efficient glazing materials  14 Annual	  energy	  consump>on	  of	  glazing	  materials	  	  Results and discussion q  Annual window heat gain and heat loss    15 Annual	  window	  heat	  gain	  and	  heat	  loss	  Results and discussion Hot-Humid climate zone      16 12.7012.9013.1013.3013.5013.7013.9014.1014.3014.5014.70WoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlWoodPvc AlEnergy Consumption (MWH)HeatingCoolingBare glasswithout shading Shading 1          shading 2          Shading 3           Shading 4           Shading 5Annual	  energy	  consump>on	  of	  various	  variables	  in	  Miami	  	  Results and discussion Mixed-humid climate zone     	  	  	  	  	  	  	  Annual	  energy	  consump>on	  of	  various	  variables	  in	  Atlanta	      17 Results and discussion Marine climate zone     18 Annual	  energy	  consump>on	  of	  various	  variables	  in	  SeaFle	  Results and discussion     19 Total	  energy	  consump>on	  of	  cold	  and	  very	  cold	  climate	  zones	  Cold and very cold climate zone Conclusions q  Shading devices’ restriction on solar radiation and the resulting reduction of cooling demand of buildings both depend on the shading configuration.     20 City Energy consumption (MWH) %Decrease in energy Glazing Material Shading Type Shading Material Orientation Miami 13.06 11.6% Ref B Tint Shading 4 Wood All Side Atlanta 11.95 7.1% Low E Tint Shading 4 Wood All Side Seattle 12.21 4.2% Low E Clear Shading 3 and 4 - All Side Chicago 18.23 3.7% Low E Tint Shading 3 and 4 - All Side Duluth 23.82 2.5% Low E Clear Shading 2 - All Side THANK YOU!  na.haghighi@gmail.com   21 

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