Chilled Water as Ice chiller condenser loop

asked 2019-10-02 14:21:17 -0600

updated 2019-10-02 14:22:34 -0600

Summary: A project i am working on is considering an approach which wants to analyze the potential of using a chilled water loop as the condenser water for an ice chiller (& thermal storage) solution. Is it possible or has any one had any luck modeling this type of configuration where the ice chiller condenser is linked as a demand side load - in Energy Plus?

Fuller details: Project has a 'normal' chilled water system 42F supply - 56F return. Supplies CHW throughout to space conditioning equipment. There are multiple low temperature (but not quite refrigeration) units, with 35F supply air temp. A strategy discussed was the potential to explore using the normal CHW system as the condenser water for the low temperature chiller(s), potentially coupled with ice thermal storage as a means to peak shave & load level. The primary goal of this would be to reduce the lift on the ice chiller, thus make it more efficiency; even though it will obviously pass more load back to the normal central plant, and eventually be rejected at the cooling towers. The question was what tools do we have to analyze this - I was curious if EnergyPlus can handle this?

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answered 2019-10-04 02:47:45 -0600

Julien Marrec

29716 ●94 ●76 http://www.effibem.com/

updated 2019-10-04 06:52:30 -0600

anchapin

626 ●2 ●9 http://nrel.gov/

A chiller can be placed on the demand side of an Plant Loop without any problems, and you're free to put whatever you want on the supply side on that plant loop, including a chiller, so there's no issue modeling your setup.

I've just setup a dummy test case in openstudio where I modeled 3 PlantLoops:

Condenser Loop with CT on supply, Primary Chiller on demand. SPM = FollowOutdoorAirTemperature with a 7°F offset on Wetbulb
Primary Chw Loop with Primary Chiller on Supply, Secondary Chiller on demand. SPM = Scheduled, 55°F
Building ChW Loop with Secondary Chiller on supply, and a coil (on a AirLoopHVAC too) on the demand side. SPM = Scheduled, 44°F

It simulated without any problems as I expected.

Here's a Gist with my model, built with OpenStudio 2.7.1 (was the version I had installed on the machine I used, don't read too much into it).