[Equest-users] Water-side Economizers NOT on Airside System?

[James Hansen]

You already know how to make it work (your last recommendation about
building a dummy zone).

 

Build a dummy zone, include the IT room max power load (KW), create a
fan coil system for that room, and just zero out the fan energy.  You'll
also need to use a free-cooling chiller in your loop.

 

Or, you can do it all thru the chiller - the free-cooling chiller
provides waterside economizer operation automatically for your chilled
water loop, and you don't have to specify a system if you don't want to.
However, I've never done it this way before, and I'm not sure if a loop
HAS to have a system attached, otherwise you might get no-flow errors
even with a process load??  You'd have to check this...

 

It would be interesting to do it both ways, and compare results.

 

GHT Limited
James Hansen, PE, LEED AP

Senior Associate

1010 N. Glebe Rd, Suite 200

Arlington, VA  22201-4749

703-338-5754 (Cell)

703-243-1200 (Office)

703-276-1376 (Fax)

www.ghtltd.com <http://www.ghtltd.com/> 

 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Cassie
Waddell
Sent: Thursday, May 13, 2010 4:47 PM
To: equest-users at lists.onebuilding.org
Cc: Amit Khanna
Subject: [Equest-users] Water-side Economizers NOT on Airside System?

 

We are designing an integrated water-side plant to serve cold water
directly to IT racks (No air). We're projecting that at 65F water
temperature, we should get more than 65% compressor-free cooling. 

 

The current modeling approach it to build a dedicated cooling system
(chiller, cooling tower, associated loops) with a direct load placed on
the loop. We are having difficulty in determining whether or not we can
model a water-side economizer using this approach because the water-side
economizer is specified within the air system (which we have none). The
issue in eQuest is how to introduce water-side economizer in a secondary
loop that only serves process loads and no zones? Is the correct way to
build a dummy zone and system and zero-out the fan power?

 

Any ideas?

________________________________
Cassie Waddell

Mechanical Engineer, LEED(r) AP

Arup 
560 Mission St, Seventh Floor

San Francisco CA 94105
tel: 1 415 946 1660
fax: 1 415 957 9096
cassie.waddell at arup.com <mailto:cassie.waddell at arup.com> 
www.arup.com

 

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