[Equest-users] Ice Storage - Chiller efficiency, etc.

[Daniel Deese]

Greg,

 

            Your best bet is to contact the (or any) manufacturer and have them tell you the chiller efficiency at the given operating conditions.  I've never tried to model a thermal storage scenario before, but I have tried to optimize a heating hot water temperature to try to take advantage of a condensing boiler, and just changing the loop temperature is not enough for eQuest to catch on.  You have to manually change the efficiencies for each piece of equipment in order to accurately model this.  I know it's not exactly what you had asked for, but I hope it helps.  Thanks.

 

daniel

 

Daniel I. Deese, EI| CRB Consulting Engineers | 

1255 Crescent Green, Suite 350 | Cary, NC 27518 | 

P: 919-852-5443 | F: 919-852-5454 | X: 4543

Email: daniel.deese at crbusa.com <mailto:daniel.deese at crbusa.com>  

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From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Greg Collins
Sent: Tuesday, March 23, 2010 5:11 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Ice Storage - Chiller efficiency, etc.

 

I have two air-cooled chillers that I'm using to charge an ice thermal storage system at night.  I have entered the EIR that equest calculated with the EER based on the chillers' normal operating conditions (44 degree CHWST).  Now, the model with ice storage is using about 46% less energy for space cooling, which is way too low.  They should be pretty close to the same..  

 

Does anybody have experience with this?  I'm thinking that equest isn't derating my chillers while they're making ice (should be ~35% decrease in efficiency).  I will probably have to get the chiller efficiencies at ice-making conditions and add 2 more chillers into equest at these conditions to charge my ice storage, and just allow the other chillers to run during the day.  Can anybody confirm this or provide any other tips?

 

Thanks,

 

Greg Collins
Design Engineer / Energy Analyst

Mechanical Department
LEED® Accredited Professional

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

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