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How to setup IDF for OpenStudio Measure Inject idf Objects?

asked 2016-11-11 14:20:05 -0500

updated 2017-08-05 07:43:04 -0500

I am trying to model in OpenStudio a chiller:electric:reformulatedEIR as per the threads below using the EnergyPlus measure in OpenStudio Inject IDF Objects. What is a good workflow for using this measure in general?

Is it best to start with a blank IDF and just enter the objects to be entered into the OS model? Or, should nodes, branches, equipment lists, etc also be added to the IDF? Or, would it work to take an out.idf generated by the OS model and add the objects to a complete IDF model? I tried the 3rd method and am having a lot of errors for duplicate objects when I run it in OpenStudio, as well as node confusion.

Also, what is the end result of this measure? Does it import idf objects into OS so I can keep working in OS, or does it mean I have to edit the model in EnergyPlus?

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I have tried the first approach I mentioned above and entered only the objects chiller:electric:reformulatedEIR, as well as curves needed for the objects. The model ran without error but did not show any difference than without the idf injected, meaning the objects were not put in the model, possibly due to node, or branch problems.

kramerica gravatar image kramerica  ( 2016-11-11 14:58:18 -0500 )edit

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answered 2016-11-14 00:00:15 -0500

If it is a very simple use case, you can start with a blank IDF, but if it is more complex I you can start with an IDF exported from OpenStudio, or produced by a simulation run. Open that IDF fie in a text editor or IDF editor and add in new objects. While new objects can refer to objets made by OpenStudio generated IDF file, you can't change fields on OpenStudio generated IDF objects to refer to the newly made objets. Once done adding new objects, optionally run the IDF through EP launch to confirm it runs, and then copy only the new objects to a clean IDF file. You don't wan to have anything in the file that OpenStudio generated. Now you can continue to work.

Once the Inject IDF measure with the clean IDF file (only new objects) is in the workflow you can continue to work on the OSM file and this measure will re-inject the new objects at run time. In your case since you need to interact with objects from the OpenStudio generated IDF a custom measure would be better. I would refer you back to the answer to this post that you referred to.

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Asked: 2016-11-11 14:20:05 -0500

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Last updated: Nov 14 '16