[Equest-users] Compressor usage with economizer

[Jeremy N. Rapoza]

All,

I am currently having a problem where the compressors on my DX units are still kicking on during the Winter months even though I have an OA economizer.  This change in results happened after I added Demand Control Ventilation as a parametric run.  The overall savings were greater, but I was surprised how much cooling increased in the winter.  My design is using Bridgeport, CT weather.

I have attached the .pd2, .inp, and .prd files.  My concern is only for units labled RTU-1, AHU-2, and AHU-3.  Please ignore all the little PSZ's.

I have done a thorough search through the archives and have found this link<http://lists.onebuilding.org/htdig.cgi/equest-users-onebuilding.org/2008-November/000614.html> to be the most similar to my problem, but I don't see any resolutions that fully fixed my problem.

Here are two of the screen shots of how I set up RTU-1, which is essentially the same as the 2 other units:
[cid:image005.jpg at 01CCBFE8.0B2DF1A0]

[cid:image006.jpg at 01CCBFE8.0B2DF1A0]

Other notes:  I only have a few unmet hours.  SS-A report will show that winter cooling is more of a problem with RTU-1 and AHU-3.  AHU-2 happens to be a 100% OA unit for Kitchen makeup and it has much less winter cooling load (not surprising since it is 100% OA so it is 'economizing' all the time.   I also have modeled this project in Trace and the results in Trace have no winter cooling as expected (this project is a training exercise for me in eQuest.)

Any help is appreciated.


Jeremy Rapoza, P.E., LEED AP, Design EngineerI BVH Integrated Services I 860.286.9171 tel I 860.242.0236 fax I 50 Griffin Road South, Bloomfield CT 06002 I www.bvhis.com<http://www.bvhis.com/>

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