Equest-users Digest, Vol 60, Issue 17

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Hi all,

I am simulating an exhaust fan in a compressor room (unconditioned) which is controlled by the room temperature. Does anyone have experience to do it?

Thanks

Danny Xu

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Joined: 2013-03-21
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Exhaust fans, as equest uses them, cannot really do exactly this. For starters, a room you control temperature in, even with only a fan, is conditioned according to equest.

I would recommend outlining the objective of including this exhaust fan and then see where in equest you should include it.

If the objective is to account for the fan energy, and the heat off the generator is predictable daily, you could ignore envelope gains and assume the fan relieves heat on a fractional schedule. I would specify this dan in the zone level exhaust or put this fan directly on the electrical meter.

If you are determined to model the responsiveness of the fan, the zone would need a dedicated fake system that ramps a supply fan up in response to temperature. Zone level exhaust fans can only be controlled to a schedule or to track with a supply fan.

Equest has a fixed way it likes to operate and move air so the modeling solution will often look odd but capture the same energy totals.

-Neil Bulger

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Thanks for your reply.

Is it possible to model it as a supply fan with cooling only and 100% OA, set the cooling capacity to 0.0001? I run a sample building with no occupant, the report show no cooling and heating, but the fan run all the year with almost same energy consumption each month. I try to set the fan control with DX-COOL-EIR, but it does not work. I expect to see the fan will not run in the winter - there is no occupant. Anyone know the reason? I did not try to set the partial load curve, if at low or no cooling load, the partial load set to zero, is it possible to work?

Thanks

Danny Xu

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Joined: 2013-03-21
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