[Equest-users] negative energy savings for infiltration reduction?

David Eldridge dse at grummanbutkus.com
Tue Nov 22 17:36:48 PST 2011


Probably not a bug! One possible explanation is that sometimes it is cooler
outside your apartment building than inside even when there is a cooling
load – during these times the infiltration is acting like an air-side
economizer to reduce the energy needed for cooling.



This effect should be offset by large gains during the coldest weather for
heating energy, and may be offset (at least partially) by gains at the
warmer times of the year for reduced cooling energy.



For Pennsylvania and New Jersey there should be a noticeable number of
hours in that middle range though, so I don’t think your results are
unexpected.



One solution might be for the energy model to account for the times the
user would turn off the A/C during that time and use their windows through
scheduling of the availability for the cooling system. You’ll have to come
up with some reasonable pattern based on your expectation for the
occupants. (Unless you don’t think they will open the windows, then the
results stand as-is.)



David



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David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP

*Grumman/Butkus Associates*

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*From:* equest-users-bounces at lists.onebuilding.org [mailto:
equest-users-bounces at lists.onebuilding.org] *On Behalf Of *steve clark
*Sent:* Tuesday, November 22, 2011 6:42 PM
*To:* equest-users at lists.onebuilding.org
*Subject:* [Equest-users] negative energy savings for infiltration
reduction?



When modeling infiltration (ACH) reduction in equest, I often get smal
negative electricity (cooling) savings and large positive heating savings.
This can occur even when air sealing is accompanied by insulation( spray
foam) for multifamily buildings in NJ and PA.

Do other people see this? IS there any explanation for this? or is a bug?

-- 
Steve Clark
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