[Equest-users] Chillers in Series inputs

[Anthony Hardman]

The keyword "SERIES-SETPT-RAT" to setup chillers in series is still listed
as future in the help files.  


Could that be why you're running into trouble?  


 

Anthony Hardman, PE

LEED AP BD&C

Building Performance Analyst

 

THE GREEN ENGINEER, LLP

Sustainable Design Consulting - Energy Modeling - LEED Project Management 

50 Beharrell St

Concord, MA 01742

O: 978/610-2801

C: 720/840-7862

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

www.linkedin.com/in/ahardman81

http://twitter.com/#!/a_Hardman

 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Pasha
Korber-Gonzalez
Sent: Friday, April 22, 2011 2:04 PM
To: James Hansen
Cc: eQUEST Users List; Arunabha Sau
Subject: Re: [Equest-users] Chillers in Series inputs

 

Thanks Rob & James for your prompt input to my dilemma....after I sent the
email to the list, I went back in my plants to try and make sense why the
secondary wasn't seeing a load--so for a random test I switched the
assignement of the two chillers (just reversed which loops they are on.) and
then ran the sim without errors.  That was the good news.   I don't have my
head around the logic of why that worked on the first try, but maybe I was
having some dislexia-input moments and spec'd my chiller conditions
backwards (i.e. high chiller & low chiller in the series).

 

Since it has ran I noticed an immediate reduction in chiller energy use, but
I haven't yet verified if the reduction is realistic and if there are any
other QC error type things to verify that this approach is indeed modeling
the chiller temps in series.   I don't think I will mess with custom chiller
curves at this point because this project model is only SD.  Therefore I
won't be held to any compliance reviews and strict performance results...at
least not at this point in time.

 

I'll try to send feedback when I can verify that this is a valid input
option for chillers in series, or if it holds no water at all...

 

Cheers,

Pasha

On Fri, Apr 22, 2011 at 12:18 PM, James Hansen <JHANSEN at ghtltd.com> wrote:

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)

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