[Equest-users] Chillers in Series inputs

[James Hansen]

Most manufacturers will give you a "single chiller" performance curve
for the two chillers in series.  I typically just make custom chiller
curves to represent series chillers as a single chiller.  If a designer
creates valving that allows water to NOT have to flow through both
chillers during low load operation, this gets a little tricky, and I end
up averaging the delta P across the chillers to represent partial
operation thru both chillers and partial operation thru a single
chiller.  No easy way to do this.

 

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 Rob
Hudson
Sent: Friday, April 22, 2011 2:15 PM
To: Pasha Korber-Gonzalez
Cc: eQUEST Users List; Arunabha Sau
Subject: Re: [Equest-users] Chillers in Series inputs

 

I won't claim that this is correct whatsoever, but briefly looking at
your set up, it is clear that the water isn't pulling extra load from
the second chiller.  I think you may want to set up a single chiller
because I don't see a way to get the water to go through both chillers.
You could also create your own custom curves so that you match the
combined performance of the modeled chiller.

 

Just a thought.

 

Rob

On Fri, Apr 22, 2011 at 1:55 PM, Pasha Korber-Gonzalez
<pasha.pkconsulting at gmail.com> wrote:

Hi,

 

I could use some guidance to make sure I'm assuming the correct inputs
to set up chillers in series.  This is the first time I'm trying to
model this and I have it set up with a primary & secondary loop for a
total delta T of 16 across 2 chillers.    I'm getting a run error of the
secondary loop having NO DESIGN FLOW/LOAD, but I'm not sure how to show
that load on the secondary loop.....maybe I have the chillers listed
backwards???

 

Can anyone take a quick look at the setup in the Plant Module and let me
know what I am missing on this?  I couldn't find any info on chillers in
series in the DOE-2 docs to guide me on the correct inputs and setup.

 

.pd2 & inp files attached.

 

Thanks in advance for your keen eye and guidance on my model.

 

Pasha


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-- 
Rob Hudson

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