Yongquing,

I confirm that I am seeing the doubling of the CH-1-HEATING input electricity in the PS-F compared with PS-H when I run your file. I have seen this doubling of the input electricity to a loop-to-loop heat pump chiller before.

In the scenario where I previously saw the doubling of the chiller input energy, I had done as you appear to have - created a dummy chilled water loop. In the scenario I had, the heat pump chillers did not generate hot water and chilled water simultaneously as the Loop-to-loop heat pump element in eQUEST does. So I created a no load dummy cooling loop which seemed to cause the doubling of input electricity.

I resolved the error by removing the dummy loop. This was done by having the heating chillers and the cooling loop-to-loop chillers on the same chilled water and hot water loops but staged them with equipment controls. In reality, I had 4 chillers that either produced hot water or chilled water simultaneously. I modelled it as 8 chillers - 4 that provided heating only and 4 that provided cooling only - but all were on the HW loop and all on the CHW loop. The heating equipment control only called on the heating chillers, the cooling equipment control only called on the cooling chillers. Then I tested to make sure they were not operating simultaneously (they weren't). This worked for me. In your scenario you may bump up against the limit of 10 pieces of equipment per primary loop so may have to combine some of your chillers.

Hoping this helps.

Brian

PS - I appreciate the reminder as this issue may be cropping up on a current project and I had forgotten about the prior problem/solution.

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Brian Fountain
Associate
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