CW Pump power issue

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Hello everyone,
I am modeling a system 8 for a LEED baseline and I'm having an interesting issue over here. The system is a VAV with PFP boxes, with one system per floor and a central chiller plant.
Now, the LEED reviewers are saying that the IT rooms should be modeled with a system 4 which sounds reasonable since the chiller should not be working on unoccupied hours just for this small room. When I make the change in eQuest, by setting an independent system for this zone, the total pump and cooling energy consumption drops significantly, which doesn't make any sense if the room is just about 1 ton in a 3000 ton system.
Has anyone had a similar issue?
Thank you!

Ing. Gast?n Michaud F.
Tel.: (506) 2222-7529
Fax: (506) 2256-5608
From USA: 1-305-433-3668
Calle 30, Avenida 0 y 2. San Jos?, Costa Rica

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Gastón Michaud Fernández's picture
Joined: 2012-11-26
Reputation: 0

Is it possible that the IT room was making the pumping/CHW system run
extra hours on nights and weekends.
Check the operating hours in PS-C command for the loop and pumps.

Thanks
Rishabh

rishabh kasliwal's picture
Joined: 2011-09-30
Reputation: 0

Did you set your Chilled Water loop to run initially on Demand rather than Standby? Standby will run the pumps continuously, Demand only operates when there is a load.

John R. Aulbach, PE

Is it possible that the IT room was making the pumping/CHW system run extra hours on nights and weekends.
Check the operating hours in PS-C command for the loop and pumps.

Thanks
Rishabh

John Aulbach's picture
Offline
Joined: 2011-09-30
Reputation: 1