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Presented by: --- University of Toronto Sustainability Office. FUME HOOD TYPES. C onstant A ir V olume ( CAV ) Exhausts at same rate no matter where the sash is As sash height is lowered, face velocity increases V ariable A ir V olume ( VAV ) Reduces exhaust rate when sash is lowered
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Presented by: --- University of Toronto Sustainability Office
FUME HOOD TYPES • Constant Air Volume (CAV) • Exhausts at same rate no matter where the sash is • As sash height is lowered, face velocity increases • Variable Air Volume (VAV) • Reduces exhaust rate when sash is lowered • Lash Miller has over 200 CAVs • Davenport has 117 VAVs
VAV ADVANTAGES • VAVs save energy, increase safety • As sash height is lowered, less air is exhausted, and less fresh air needs to be brought in and conditioned • Avoids dangerously high face velocities
HIGH ENERGY DEMAND • Fume hoods exhaust large volumes of air • Exhausted air must be replaced by fresh air from outside • Electricity used to cool air (summer), power fans • Natural gas used to heat air (winter) • Humidity adjustment may require both cooling and heating • VAV hoods: lower sash = less air exhausted = less energy costs and greenhouse gas emissions
POTENTIAL SAVINGS • If fume hoods are always closed when not being used, we can save over: • 506 MWh of electricity per year • 8030 mmBTU of fossil fuel energy per year • 562 tonnes GHG emissions per year • $175,000 in operating costs per year
SAFETY CONCERNS • VAV system assume diversity in sash heights to save fan energy and capital costs • Fans sized for only 50% of hoods to be used at once • Low-flow alarms = contaminants leaking out! • Even at normal flow, contaminants can leak out of open hoods when: • Someone walks past it • A door is opened • Explosion containment
JUST SHUT IT! CAMPAIGN • Developed, organized by the Sustainability Office, Department of Chemistry and Chem Club • Funded by the Ontario Ministry of Energy and Infrastructure’s Community Conservation Initiatives program* • Aim to change behaviour and make sash closing a habit, like turning off the tap • Modeled after very successful campaigns at Harvard, MIT and Duke * The views expressed in this campaign are the views of the Sustainability Office and do not necessarily reflect those of the Province.
JUST SHUT IT! COMPETITION • Individual users and research groups can receive prizes for closing their hoods • Sash Patrol volunteers will check your fume hood sash height at random times
JUST SHUT IT! COMPETITION • They will be putting stamps or stickers on your hood’s recording card if your hood is: • At or below 14.5 inches when in use; or • At or below 2.0 inches when not in use • Each stamp is worth one ticket in a raffle at the end of the campaign • Monthly results: • http://www.sustainability.utoronto.ca/fumehoods
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