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How to change idd file to allow Fan:SystemModel on Branch?

asked 2018-10-12 13:43:18 -0500

mldichter gravatar image

updated 2018-10-17 16:05:43 -0500

Running the newest version of energyplus with idf editor claims the Fan:SystemModel is not a valid object to put on a Branch, even though the simulation runs fine.

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How do I alter the idd file so my measures can place Fan:SystemModel objects on Branch objects?

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Added openstudio-measure tag since the main question is how to get the measure to work. The IDF Editor validity check is secondary.

MJWitte gravatar imageMJWitte ( 2018-10-17 16:06:45 -0500 )edit

@MJWitte Changing the idd file has worked before. There was a similar issue here. But that fix didn't work this time. Do you know if the way workspace.addObject(object) determines if the object being added is valid or not with reference to an idd file has changed?

mldichter gravatar imagemldichter ( 2018-10-17 16:41:57 -0500 )edit

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answered 2018-10-15 16:59:09 -0500

It is the references list in each type of fan that determine if the fan is allowed in certain locations (e.g., branch or HVAC objects). The problem here is that the last 2 versions of E+ no longer read the idd at runtime and changing these characteristics of objects in the idd does not take effect unless the program is compiled (i.e., you will not be able to correct it by only changing the idd). Compiling the program will create a new Energy+.schema.epJSON file which is read during program execution. The plan is to eventually remove the idd file and use only JSON format.

Fan:SystemModel,
  A1 , \field Name
       \required-field
       \reference Fans
       \reference FansCV
       \reference FansCVandOnOff
       \reference FansCVandOnOffandVAV

Fan:ConstantVolume,
  A1 , \field Name
       \required-field
       \reference Fans
       \reference FansCV
       \reference FansCVandOnOff
       \reference FansCVandVAV
       \reference FansCVandOnOffandVAV
       \reference-class-name validBranchEquipmentTypes
       \reference validBranchEquipmentNames
       \reference-class-name validOASysEquipmentTypes
       \reference validOASysEquipmentNames
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@rraustad I looked up compiling energyplus, and it looked a bit involved. Do you have an estimate of when the bug will be fixed in the energyplus installer I can download from https://energyplus.net/downloads? Are minor revisions released frequently?

mldichter gravatar imagemldichter ( 2018-10-15 17:06:13 -0500 )edit

There is no scheduled release of minor revisions. It does happen, but not regularly. I will post an issue and this might get fixed quickly. I anticipate a minor revision for other issues I see in this release, however, I can't provide a time frame.

rraustad gravatar imagerraustad ( 2018-10-15 17:14:57 -0500 )edit
rraustad gravatar imagerraustad ( 2018-10-15 17:23:11 -0500 )edit

@MJWitte went ahead and fixed this just now here. When/If there is a minor release this will be included.

rraustad gravatar imagerraustad ( 2018-10-15 18:13:18 -0500 )edit

Thinking about this, it may be that IDF Editor does still use the idd for error checking. Why don't you try adding the missing references and see if the IDF Editor recognizes the Fan:SystemModel on a branch.

rraustad gravatar imagerraustad ( 2018-10-15 18:16:56 -0500 )edit
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answered 2018-10-16 07:12:53 -0500

Since the issue you are facing is with IDF Editor and not EnergyPlus, you should be able to edit the Energy+.idd file and fix the issue that you are seeing. Make the edits shown here in your local Energy+.idd file and restart the IDF Editor.

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Asked: 2018-10-12 13:43:18 -0500

Seen: 79 times

Last updated: Oct 16