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EIR Chiller Performance Factors

asked 2016-11-11 11:10:39 -0600

Matt Koch gravatar image

updated 2016-11-11 12:13:15 -0600

I have studied the definitions of ChillerCapFTemp, ChillerEIRFTemp and ChillerEIRFLR and have reached a point where I believe ChillerEIRFPLR may not be defined correctly? I have summarized my findings in a PDF document, but I noticed I cannot post this here. So I exported to three PNG files instead, which are attached.

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I hope they will be legible, and I apologize for the length, but I thought I'd try to be as clear about my thoughts as possible. I'd appreciate any advice.

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I was just curious if anyone might have had a chance to review the above? I apologize for the complexity of the presentation, but do not know how else to make my question as clear as I possibly can. Or is all of this going to go away in OpenStudio 2.1?Thanks.

Matt Koch gravatar imageMatt Koch ( 2017-01-05 15:21:42 -0600 )edit

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answered 2017-01-06 09:09:09 -0600

See if this helps:

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Update: Correct equation for ChillerEIRfPLR is available in the Engineering Reference document up to V8.4.

rraustad gravatar imagerraustad ( 2017-01-06 09:21:20 -0600 )edit

Where do you see in the documentation that the definition of f3 is EIRact/EIRcap ? Or is it simply your translation of the variable name?

rraustad gravatar imagerraustad ( 2017-01-06 09:29:49 -0600 )edit

Two thoughts:

1) Your explanation seems to confirm that ChillerEIRFPLR is indeed equal to what I refer to as bar(f)3.

2) My definition of f3, i.e. NOT bar(f)3, is based on: "The output of this curve is multiplied by the reference EIR (inverse of the reference COP) and the Energy Input to Cooling Output Ratio Function of Temperature Curve to give the EIR at the speicfic temperature and part-load ratio at ehich the chiller is operating." (

Matt Koch gravatar imageMatt Koch ( 2017-01-06 11:22:13 -0600 )edit

so, further to item 2): EIRref = Pref/Qref, EIRact = Pact/Qact, ChillerEIRFTemp = EIRcap/EIRref, where I am assuming that ChillerEIRFTemp is the "Energy Input to Cooling Output Ratio Function of Temperature Curve" of the above definition. Therefore, ChillerEIRFPLR * EIRref * ChillerEIRFTemp = EIRact, or ChillerEIRFPLR * EIRref * EIRcap/EIRref = EIRact. Hence: ChillerEIRFPLR = EIRact/EIRcap, which is my definition of f3.

Matt Koch gravatar imageMatt Koch ( 2017-01-06 11:28:35 -0600 )edit

so, I am thinking if your derivation from the EnergyPlus Engineering reference is indeed on target, then perhaps all that needs to e changed is the verbal definition in

Matt Koch gravatar imageMatt Koch ( 2017-01-06 11:32:21 -0600 )edit

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Asked: 2016-11-11 11:10:39 -0600

Seen: 1,567 times

Last updated: Jan 06 '17