[Bldg-sim] Equest:Variation in pumping energy for Baseline system 8

[John Aulbach]

Vishnu:

I am guessing you let eQuest size the pumps. I will also bet you have the pumps set on STANDBY vs. DEMAND, Therefore, CHW pumps run all the time for the two chiller scenario, regardless if two chillers are needed.

See if that helps.



John R. Aulbach, PE, CEM
Senior Energy Engineer

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________________________________
From: Vishnuraj Nair <vishnu at kalpakrit.com>
To: bldg-sim at lists.onebuilding.org
Sent: Wed, March 17, 2010 4:26:51 AM
Subject: [Bldg-sim] Equest:Variation in pumping energy for Baseline system 8


Dear friends, 
I am working on two projects of core and shell where the baseline system is system 8 i.e VAV with fan powered boxes.
There are two different building which are very similar in nature (not same) and situated at same location.
However there are differences in the way the two models are behaving.
I have shown the breakdown of different end uses as a percentage of overall baseline energy consumption
 
Project 1
Plug loads:        25.5 % 
Interior Lighting: 16%
Cooling energy:  28.7%
Fan energy:       21%
Pumps:             6.3 %
Space heating:  0.1%
Domestic hot water + Exterior Lighting: 1.3 %
 
Project 2
Plug loads:        24 % 
Interior lighting:  15%
Cooling energy:  18%
Fan energy:       25%
Pumps:             15 %
Space heating:  0.3%
Domestic hot water + Exterior Lighting: 1.3%
 
 
It can be seen that the energy consumed due to plug loads and interior lighting as a percentage of baseline are all most equal in both the cases.
Can anyone suggest possible explanation or give hints as to why the pumping energy as a percentage of baseline has more than doubled in the
 second case given that the characteristics of chiller, condenser and pump remain same ,given it is the baseline case. 
One difference is that the first project uses two chillers as it has conditioned area more than 1, 20,000 sq ft while the second project has only
 one chiller ,its conditioned area being less than 1, 20,000
Vishnuraj Nair
Kalpakrit Sustainable Environments Pvt. Ltd.  
New Delhi
Tel: +91.124.4309490-92 Ext: 312 , Fax: +91.124.4309493
E-mail : vishnu at kalpakrit.com
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