creating performance curves

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Hi guys,

I'm trying to create chiller part load EIR curves based on manufacturer data. I have part load (25%, 50%, 75%, 100%) as the independent variables (X), and part load EIRs as the dependent variable (Z). The part load EIRs from manufacturer are much better than what I get when I use default EQUEST curve. But when I run the model and compare with same model with default curve, my chiller electrical energy consumption is increased significantly (with the manufacturer data). Has anyone been able to successfully create performance curves, or does anyone know of any documentation that might explain how to properly create these curves? Any help is greatly appreciated.



Behnam Jowkar, MASc

Behnam Jowkar's picture
Joined: 2012-03-29
Reputation: 0

This always gets confusing but I believe the curve labeled as EIR-fPLR is
not actually EIR as a function of part-load-ratio.

I believe it is input ratio (operating kW as a ratio of full load kW) as a
function of part load ratio, so you have to set up your custom curves
based on those parameters. The input ratio value should be 1 at the 100%

Nathan Miller, PE, LEED AP BD+C

Nathan Miller's picture
Joined: 2011-09-30
Reputation: 200

There is a document written by Steve Gates that explains how to create custom chiller curves and an example spreadsheet of mine which you can download from the following site:


Jeremy McClanathan, P.E., BEMP, HFDP, LEED(r) AP

Jeremy McClanathan's picture
Joined: 2011-09-30
Reputation: 200

See attached cooltools spreadsheet.

bfountain's picture
Joined: 2011-09-30
Reputation: 201