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chiller performance curve

asked 2016-10-14 13:55:58 -0500

Dan McJacobson gravatar image

I would like to be able to compare the energy savings of different manufacturers' chillers in OpenStudio. I know a number of posts have discussed where the default chiller performance curves come from, and that the coefficients in the .idf files can be edited. I am looking for the most simple way to either generate the coefficients, or hopefully find a component/measure that allows direct entry of known performance values in the OpenStudio interface.

Example Manufacturer Data:

85°F, 100% load, 0.5622 kW/ton;

75°F, 100% load, 0.4490 kw/ton;

85°F, 70% load, 0.5293 kw/ton;

75°F, 70% load, .3444 kw/ton;

Appreciate the help!

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8

answered 2016-10-14 22:02:36 -0500

If you have performance data from the manufacturer the EnergyPlus CurveFitTool.xlsm can be used to derive the performance curve coefficients. The tool can be found in:

C:\EnergyPlusV8-6-0\PreProcess\HVACCurveFitTool

or

C:\Program Files\OpenStudio 1.13.0\share\openstudio\EnergyPlus-8-6-0\PreProcess\HVACCurveFitTool

These coefficients can then be entered into the fields of the biquadratic and quadratic curves associated with a ChillerElectricEIR object in OpenStudio.

If you'd like to visualize the curves, I've added the the charts from the COMNET Appendix H - Equipment Curves spreadsheet to the EnergyPlus CurveFitTool, to create an Improved CurveFitTool, which I've committed to my GitHub fork.

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6

answered 2016-10-18 10:28:50 -0500

Carlos Vazquez gravatar image

You can also use this spreadsheet from the energyplus support website. Just copy ans paste the link in your browser: energyplus.helpserve.com/Knowledgebase/Article/GetAttachment/135/5844

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Asked: 2016-10-14 13:55:58 -0500

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Last updated: Oct 18 '16