[Equest-users] CHW temp and cooling coil leaving temp

[Erik Kolderup]

Josh,

 

You need to consider fan heat. If it's a draw-through coil, then eQUEST
knows that the SAT leaving the coil needs to be lower than the zone entering
temperature. So in your case, when you enter 55F for zone entering
temperature, then the coil leaving temperature is 55F minus the fan delta T.


 

-Erik Kolderup

 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Josh
Doherty
Sent: Wednesday, April 22, 2009 10:16 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] CHW temp and cooling coil leaving temp

 

HI,

I am trying to model a VAV system for cooling and heating.  On the cooling
side, I specify a 52F CHW loop temperature and a "Zone Entering Min Supply
Temp" of 55F.  When I run the simulation I get an error that states "cooling
coil leaving temperature must be at least 6F higher than entering water
temp".  I played with adjusting the "Zone Entering Min Supply Temp" to see
what minimum value would work without errors and the lucky number was 61F.
I am trying to figure out why this is the minimum temperature eQuest accepts
without errors.  The 61F is 9F higher than the entering water temperature
and not 6F like the error states.  Any ideas what is going on?  Thanks so
much for your help and insight.

 

Josh Doherty

 

 

 

 

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