UBC Graduate Research

UBC energy audit : laboratory ventilation and fume hoods Gretka, Voytek


This study focuses on estimating the potential energy savings regarding general laboratory ventilation with special emphasis on fume hood ventilation practices. The initial scope of the study aimed to audit all of the laboratory space on UBC’s Point Grey campus. It is well established that a fume hood uses as much energy as three houses; since there are approximately 1000 fume hoods on campus, this represents a significant fraction of campus energy use and therefore provided the motivation for the audit. The focus of the study was to investigate measures in which energy could be saved by identifying unnecessarily over-ventilated laboratories. Traditionally, it was assumed that hazardous chemicals used in laboratories (carcinogens, etc.) presented an elevated health risk that should be addressed via increased ventilation. Conventional wisdom has recently been scrutinized by scientific studies proving that in fact the improvement in air quality is negligible past a certain threshold of Air Changes per Hour (ACH). Likewise, increased fume hood ventilation rates may cause turbulent eddies and disrupt the ideal air containment strategy within the hood which may decrease worker safety. The following are four specific measures that were evaluated: (1) Decreased Air Change Rates (Unoccupied Night Setback with Manual Occupancy Override) (2) Low-Flow Fume Hood Retrofit (3) Reduce Constant Air Volume (CAV) Fume Hood Face Velocity to 90fpm (4) Implement Variable Air Volume (VAV) Fume Hood Alarms These measures were evaluated where applicable in the following buildings: -Chemical and Biological Engineering Building (CHBE) -Advanced Materials Processing and Engineering Laboratory (AMPEL) – Brimacombe Building -Earth and Ocean Sciences – Main (EOSM) -Chemistry Centre, D-Block (CHEM D) The potential reduction of fume hood face velocity was also extrapolated to the entire campus for a general assessment of how much energy could be saved. Table 9 in Section 4.3 neatly summarizes the important parameters for each energy-savings measure. Energy cost savings were estimated using a rate that included the cost of heating, cooling, and mechanically moving a cubic foot per minute (CFM) of air per annum. Based on current energy and carbon tax costs, the rate used was $2.69/(CFM·yr). The study concluded that nearly all projects are financially viable with the exception of low-flow fume hood retrofits that have a capital cost too high to be able to regain in energy savings in a reasonable amount of time. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”

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