Problem with ShopWithSimplePVT idf

asked 2018-01-05 13:02:06 -0600

mldichter
2565 ●2 ●11

updated 2018-01-07 08:52:17 -0600

The ShopWithSimplePVT idf file shows invalid fields for Collector # Branch with # replaced with 1,2,3,4,5. This shouldn't be the case as the fields Collect # objects all exist, but they aren't present in the drop down list to pick from. The simulation doesn't complain though.

I encountered this problem while writing a measure to automatically add PVT to a building. Everything was going smoothly until I tried adding a Branch with a SolarCollector:FlatPlate:PhotovoltaicThermal object in the Component 1 Name field using

idfObject = OpenStudio::IdfObject::load(idf_string)
object = idfObject.get
wsObject = workspace.addObject(object)

but the string for the Component 1 Name field is not successfully added because it's not in the drop down list in the IDF editor. My current workaround is to name the Shading object for the PVT panel and the PVT object the exact same string. The Shading object name is then in the drop down list of objects to add in the Component 1 Name field, the measure can successfully add the name of the PVT panel (even though the IDF editor thinks it's adding the name of a shading object), and the simulation runs without complaining about the Branch object.

Here is a link for the ShopWithSimplePVT idf file and a png showing the highlighted orange Component 1 Name fields in my google drive
https://drive.google.com/open?id=1q4S...

Edit: Using EnergyPlus 8.8.0

The IDFeditor isn't an insurmountable obstacle as I can forcibly write in the correct PVT name in the Branch object field. It's inconvenient to not have the PVT object name in the drop down menu, but easily fixed for one model. I really need to automate the process though. I'm working on a project to automate generation of building models to try and reach a zero net energy building in the most cost effective way. To do that, we're making measures that add skylights, change insulation, add PVT to a building, etc. We are also changing the percent of the roof that is windows, PVT, etc. As a consequence, we expect to have on the order of a million different simulation to run. Unfortunately, an EnergyPlus measure won't add what is considered an invalid object name to an IDF object field. Normally this is a good thing because the program makes sure I'm not using an object name that doesn't exist and makes debugging much easier. In this case though, I'm being prevented from adding an object that does exist, the PVT object name in a Branch object field.

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Comments

@mldichter Could you tag which apps you use (OS, E+...) and please state which versions.

Avi ( 2018-01-06 02:13:16 -0600 )edit

Anyway it seems that there might be an issue in the IDFEditor which should not prevent you from adding PVT to Branch unless you insist on doing that manually in the IDFEditor. Even then you can type in the name of the collector and it will do.

Avi ( 2018-01-06 03:15:04 -0600 )edit

@Avi I added which version of EnergyPlus I'm using.

mldichter ( 2018-01-06 11:10:12 -0600 )edit

@Avi I edited my post in response to your second comment. To be able to write an energyplus measure that can add the PVT object name in a Branch object field is a must for me to automate model generation.

mldichter ( 2018-01-06 11:24:16 -0600 )edit

@mldichter It might be me but I can't understand whether you are using OpenStudio to apply E+ measure or you do something else? And please post the error you get when you run the E+ measure

Avi ( 2018-01-06 12:09:16 -0600 )edit

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answered 2018-01-08 19:45:11 -0600

MJWitte

9740 ●6 ●10 http://www.gard.com/

There is a mistake in the Energy+.idd file. This is the incorrect block in the v8.8.0 IDD:

SolarCollector:FlatPlate:PhotovoltaicThermal,
   \memo Models hybrid photovoltaic-thermal (PVT) solar collectors that convert incident solar
   \memo energy into both electricity and useful thermal energy by heating air or water.
A1 , \field Name
   \reference-class-name validOASysEquipmentTypes
   \reference validOASysEquipmentNames
A2 , \field Surface Name
   \required-field
   \type object-list
   \object-list AllShadingAndHTSurfNames
   \reference-class-name validBranchEquipmentTypes
   \reference validBranchEquipmentNames

The last two lines are causing the PVT Surface Name to appear in the Branch Component Name drop-down list. Those lines should be moved up before the A2 field line:

SolarCollector:FlatPlate:PhotovoltaicThermal,
   \memo Models hybrid photovoltaic-thermal (PVT) solar collectors that convert incident solar
   \memo energy into both electricity and useful thermal energy by heating air or water.
A1 , \field Name
   \reference-class-name validOASysEquipmentTypes
   \reference validOASysEquipmentNames
   \reference-class-name validBranchEquipmentTypes
   \reference validBranchEquipmentNames
A2 , \field Surface Name
   \required-field
   \type object-list
   \object-list AllShadingAndHTSurfNames

If you make this change in the EnergyPlus-V8-8-0\Energy+.idd file, then IDF Editor will no longer tag the collector names as invalid and the names will be in the drop-down list.

I am not sure if OpenStudio EnergyPlus measures read this same IDD file or a separate IDD that is part of the OpenStudio install, so you may need to make this change in two places. The pending fix is here in this pull request.