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refrigeration compressor curve type

asked 2016-02-29 12:23:39 -0600

Ritesh gravatar image

updated 2016-02-29 13:41:53 -0600

For the compressor capacity and power curves in OS, are there any other option besides Bi-Cubic type? How do I create a polynomial curve for capacity and power.


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answered 2016-03-01 01:42:32 -0600

Chandan Sharma gravatar image

Looking at the Refrigeration:Compressor object in Energy+.idd and in Input Output reference, input fields Refrigeration Compressor Power Curve Name and Refrigeration Compressor Capacity Curve Name only allow bicubic curves.

EnergyPlus data sets folder (C:\EnergyPlusV8-4-0\DataSets) has RefrigerationCompressorCurves.idf which contains extensive data sets for refrigeration compressor capacity and power curves. See Output Details and Examples for more information on this.

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Keep in mind that refrigeration curves are conceptually different than other curves within E+. For a DX coil, the curves result in a fractional value, e.g. .92, which gets multiplied by the rated coil capacity. For a refrigeration compressor, the result is the actual capacity in watts. That means a different set of curves is needed for each compressor model! It's rather annoying and time-consuming unless you have one of the compressors in the data set that Chandan mentioned.

Jim Dirkes gravatar image Jim Dirkes  ( 2016-03-01 09:41:21 -0600 )edit

Thanks Chandan. The information was very helpful.

Ritesh gravatar image Ritesh  ( 2016-03-01 10:53:07 -0600 )edit

Jim, I am currently reviewing a model done by another engineer and the compressor is not defined in the data sets. Therefore, I am having difficulty figuring out where did all the coeffecients came from. I only got the .OSM file. So I am inclined to believe that he (the engineer) might have inputted custom coefficients in the data set that I dont have access to.

Ritesh gravatar image Ritesh  ( 2016-03-01 10:54:53 -0600 )edit

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Asked: 2016-02-29 12:23:39 -0600

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Last updated: Mar 01 '16