[Equest-users] CHW delta T in eQUEST

[Umesh Atre]

Rohini/Bob/Lance,
 
Thanks for your help,
Much appreciated.
 

 
________________________________

From: Lance Brown [mailto:lance at andelmanlelek.com] 
Sent: Tuesday, August 09, 2011 1:36 PM
To: equest-users at lists.onebuilding.org
Cc: Umesh Atre
Subject: RE: [Equest-users] CHW delta T in eQUEST



Since you didn't change the CHW supply temperature, the drop in chiller
load is a result of warmer return water returning to the chiller and
improving the rate of heat transfer to the evaporator. The drop in heat
rejection is a direct result of the reduced chiller load.

 

Depending on your HVAC system parameters, you may have seen an increase
in fan energy to account for the less efficient heat transfer taking
place at the cooling coils.

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Umesh
Atre
Sent: Tuesday, August 09, 2011 11:39 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] CHW delta T in eQUEST

 

I am trying to determine the effect of increasing the chilled water
delta T on the energy consumption in an office building. I set up 2
models, 

one with 10 deg delta T, and the other increased to 15 deg on the
chilled water loop (elec. centrifugal chiller was used). All other
parameters are same in both models.

 

The results show a drop of ~14% in pump energy, but they also show a
reduction on both the cooling (~6%) and heat rejection (~3%). 

Why does the increase in chilled water delta T show savings on these 2
other end-uses? 

 

Thanks for any help

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20110809/0188c968/attachment-0002.htm>