[Equest-users] High Cooling and Fan energy use VAV? Advice needed

[John Aulbach]

Quick take, as I haven't look at your runs. But setting the Thermostat to Reverse Action and having a throttling range of 4 - 6 DegF (Forget the R they have displayed). That should knock down your unmet hours, and maybe your fan.

John R. Aulbach, PE, CEM
Senior Energy Engineer

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From: Patrick O'Donnell <pco at MichaelsEngineering.com>
To: equest-users at lists.onebuilding.org
Sent: Thu, June 3, 2010 11:57:48 AM
Subject: [Equest-users] High Cooling and Fan energy use VAV? Advice needed


Hi all,
Iam having a hard time getting this VAV systemto be efficient; more specificallythe cooling and fan energy seems way too highand I cannot figure out why.  This system serves a spaceinan insulatedbuilt-outoffice space that islocatedwithinan insulatedproduction space.  The production space has heating only andgenerates some of its own internal loads. 
It is the office spaces that I am concerned with(set on their own metersEM1and FM1 ). There is some load diversity i.e. some rooms have some significant equipment and occupant loadswhile others do not.
·      Coolingcapacity seems  reasonable(this system is auto sizing), supply cfm seems normal.
·      The fans are running whenever the system is on.  
·      Looking at the hourly reports,I think the economizer is working properlyand modulating open for free cooling when OA temp is below the setthreshold.
·      Unmet load hours for coolingarealso very high.
·      Internal loading, occupancy, etc should be accuratehowever it should be noted that infiltrationinto the office spaces is intentionally set pretty highaccounting forminimal sealing of spaces.
I think I have some of the controlsgoofed upor scheduling conflictsbut am not sure.  Thank you very much in advance for any assistance/insight you can provide!!  Attached are the modeling files.
-Patrick
<<OfficeBuildout_VAV4.inp>> <<OfficeBuildout_VAV4.pd2>> 


      
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