Chemistry Laboratory Energy Model

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I am about to begin an energy model for a large university lab project that includes about 150 VAV chemical fume hoods. The building systems will include a true VAV exhaust system, not a bypass VAV system. Please advise how this can be modeled using Trace. Thank you in advance.

Nick Kugler, LEED AP

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Joined: 2011-09-30
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I think getting the exhaust fan to be VAV should be the easy part - just assign a VAV fan type to that fan on the Systems fan tab page. The tricky part is going to be getting the cfm to model correctly.

Given that there are so many fume hoods, it sounds like your airflows to labs will likely be dictated by fume hood make up. You will need to do a some design level runs to be sure.
If the airflows are fume hood driven, then you'll need to develop a schedule of the fume hoods likely use - this schedule would be used in both the proposed and baseline cases. Determining the schedule is the hardest part - you may need owner input on expected fume hood use and how good they are at closing their fume hoods when not in use. You will need to have this conversation with them anyway to determine the level of diversity for your fume hood exhaust system sizing anyway....so, it's a matter of going into more detail on that discussion for energy modeling purposes. Your owner may not know the answers, but, at least you can use the conversation as a basis for design and energy modeling and means to estimate something. Once you develop the fume hoods use schedule, you can then force the cfm to each lab at the room level (supply and exhaust) and then apply the schedule to those cfms.

Julia Beabout's picture
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Joined: 2011-10-01
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Hey Nick,

I would suggest to use a VAV system and provide 100% available schedule
for the exhaust cfm and fan, at room level. Then at system level assign
the strobic fan static and energy rate. You should be very close to the
actual situation.

Hope this helps.

Thanks,

Fareed Syed EIT, LEED(r) AP

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What about considerations for energy recovery at the system level?

Nick Kugler, LEED AP
Mechanical Engineering

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Joined: 2011-09-30
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Go to Create Systems ? Options ? Stage 1 Air-to-Air Energy Recovery/Transfer ? Type.... Sensible wheel or whatever you want to pick.

Hope this helps you.

Thanks,

Fareed

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