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How to add/define part load performance curves using Openstudio?

asked 2015-04-01 12:17:12 -0600

adam.diplacido's avatar

updated 2015-04-07 11:41:23 -0600


I am having trouble figuring out how to add part load performance curves for both a fuel-fired water heater (mixed) and a gas heating coil in Openstudio v1.5. Opening these HVAC items in the edit window, I can see the blank to select the Curve, but no way to define a new curve.

Thanks in advance!

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Thanks for your response Julien. By text mode do you mean export to idf and then use the text editor or does Openstudio itself have a text mode?

adam.diplacido's avatar adam.diplacido  ( 2015-04-01 13:49:20 -0600 )edit

The openstudio file (OSM) is nothing but text really (just like the idf). Right click the .osm file and open with a text editor, like notepad++. Search for "OS:Curve".

Julien Marrec's avatar Julien Marrec  ( 2015-04-01 13:54:55 -0600 )edit

Thanks for the easy fix!

adam.diplacido's avatar adam.diplacido  ( 2015-04-01 15:54:27 -0600 )edit

3 Answers

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answered 2015-04-01 23:25:11 -0600

updated 2015-04-06 14:56:28 -0600

As of OS 1.7.0 it doesn't appear that these curves can be selected or edited by the user. @Julien Marrec's answer could be a quick fix, but you might run into trouble if you edit the handles.

An alternative is to write a measure to set the curves for the WaterHeaterMixed and CoilHeatingGas objects using setPartLoadFactorCurve and setPartLoadFractionCorrelationCurve respectively.

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answered 2015-04-01 12:58:22 -0600

updated 2015-04-02 00:56:08 -0600

As of 1.7.0 this is still true.

As a quick fix you can go in text mode, copy a quadratic curve (for water heater) and modify the values, including the name and handle. Open the .osm file with a text editor and search for OS:Curve.

For the handle, as it has been already discussed on this thread Creating handles for OSM objects, instead of changing a number or too it is best to generate a new version 4 UUID (for example here)

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answered 2015-04-02 09:30:31 -0600

All of the answers above sound good to me. I'd just add that you could do what they are suggesting to the hvac_library along the lines here. Then you have access to this feature in all of your models.

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Asked: 2015-04-01 12:17:12 -0600

Seen: 477 times

Last updated: Apr 07 '15