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Performance Curves for OpenStudio

asked 2015-06-30 10:47:41 -0500

Brian C's avatar

updated 2015-06-30 10:49:23 -0500

I would like to know what other's have done for performance curves in OpenStudio. Does someone have a comprehensive library for performance curves for equipment? I have found this document online (Appendix 5.7 Performance Curves), and it looks helpful but I'm not sure how to make sense of it (when I use the performance curves from this spreadsheet I get errors when I run my model). If you don't have a comprehensive list of performance curves, anything would be helpful especially curves for variable speed pumps and fans. Thanks!

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Do you want to create performance curves from measured data you have collected?

Clayton Miller's avatar Clayton Miller  ( 2016-01-14 20:42:58 -0500 )edit

The EnergyPlus Input/Output reference provides great help, I think ( This gives you a general idea of how these performance curves are defined. Then you can go into, for example, the EIR chiller section ( and see which temperature corresponds to x or y.

Matt Koch's avatar Matt Koch  ( 2017-08-07 08:08:52 -0500 )edit

You can do the same with variable volume fans ( and variable speed pumps (, for example. However, like you, I have no seen a comprehensive library yet and need to "roll my own" every time.

Matt Koch's avatar Matt Koch  ( 2017-08-07 08:10:56 -0500 )edit

The only thing I know of that comes close is the libraries available under the EnergyPlus DataSets directory. But these are IDF files, not OSM file, so you would have to manually copy/paste the coefficients, or write a measure somehow. Unfortunately, measures are much beyond my capability.

Matt Koch's avatar Matt Koch  ( 2017-08-07 08:14:44 -0500 )edit

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answered 2017-12-11 20:04:01 -0500

updated 2017-12-11 20:05:12 -0500

Appendix 5.7 is a supporting document to the California Title 24 Part 6 Nonresidential Alternative Calculation Method (ACM) manual. It outlines the capabilities and rules for CBECC-Com (California energy code compliance software). It is a valid source for curve coefficients, though I do not know what the source of the coefficients are.

When looking at this document, be careful to identify E+ vs DOE-2 curves. E+ curves were created based on SI units, and DOE-2 curves are based on IP units. Some curve types are unit-independent (i.e. fan and pump curves) and others are not (i.e. chiller curves). You cannot use SI unit chiller curve coefficients in a software if you are using IP, and you will see some odd results. For fans and pumps there isn't an issue as the curve coefficients are interchangeable between units.

Another source for a VSD fan curve is ASHRAE 90.1 Appendix G:

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T24 coefficients come from a 2003 CEC report "Advanced Variable Air Volume System Design Guide" Appendix 5 - DOE-2 Fan Curves, which were created by Jeff Stein and Mark Hydeman from a "Characteristic Curve Fan Model" they developed, detailed in "Development and Testing of the Characteristic Curve Fan Model" ASHRAE Transactions. 2004, Vol. 110 Issue 1, p347-356. 10p.

mdahlhausen's avatar mdahlhausen  ( 2017-12-13 12:05:00 -0500 )edit

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Asked: 2015-06-30 10:47:41 -0500

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Last updated: Dec 11 '17