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CoilHeatingLowTempRadiantVarFlow does not get added to the demand side of a plant loop in IDF anymore

asked 2024-06-21 10:53:32 -0500

TobiasMaile's avatar

updated 2024-06-21 15:12:32 -0500

The following code works fine in OpenStudio 3.0.1 but not anymore in 3.2 and above. I found that the heating/coiling coil is an optional component now, so I used the get method. Still, something else must have changed so that the CoilHeatingLowTempRadiantVarFlow object is no longer converted into an IDF object.

heatingCoilBaseboard= OpenStudio::Model::CoilHeatingWaterBaseboard::new(model) baseboard =, model.alwaysOnDiscreteSchedule(), heatingCoilBaseboard)

baseboard.addToThermalZone(zone) hotWaterPlant.addDemandBranchForComponent(baseboard.heatingCoil())

heatingCoilRadiant = OpenStudio::Model::CoilHeatingLowTempRadiantVarFlow::new(model, zoneHeatingTempSched) coolingCoilRadiant = OpenStudio::Model::CoilCoolingLowTempRadiantVarFlow::new(model, zoneCoolingTempSched)

radiantLowTVarFlow =, model.alwaysOnDiscreteSchedule(), heatingCoilRadiant, coolingCoilRadiant) radiantLowTVarFlow.setNumberofCircuits("CalculateFromCircuitLength")


hotWaterPlant.addDemandBranchForComponent(radiantLowTVarFlow.heatingCoil().get) chilledWaterPlant.addDemandBranchForComponent(radiantLowTVarFlow.coolingCoil().get)


zone.setCoolingPriority(baseboard, 3) zone.setHeatingPriority(baseboard, 2) zone.setCoolingPriority(radiantLowTVarFlow, 2) zone.setHeatingPriority(radiantLowTVarFlow, 3)

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Can you upload your OSM to e.g. Google Drive or Dropbox? Not sure anyone can help without more information. Also, it maybe related to

shorowit's avatar shorowit  ( 2024-06-25 14:02:06 -0500 )edit

Here are two OSM files one in version 3.0.1 and one in version 3.7.0. The first one runs fine and the second one creates the following error message: * Severe * <root>[Branch][Chilled Water Loop Demand Branch 1][components][0] - Missing required property 'component_name'.

OSM 3.0.1

OSM 3.7.0

TobiasMaile's avatar TobiasMaile  ( 2024-07-03 09:35:16 -0500 )edit

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answered 2024-07-03 11:30:41 -0500

OpenStudio is providing a warning that indicates the issue:

[openstudio.energyplus.ForwardTranslator] <-1> Object of type 'OS:ZoneHVAC:LowTemperatureRadiant:VariableFlow' and named 'Zone HVAC Low Temperature Radiant Variable Flow 1' does not have any target surfaces with ConstructionWithInternalSource, it will not be translated

The issue is that you're calling radiantLowTVarFlow.setRadiantSurfaceType("Ceiling") but you don't have any ceiling surfaces with ConstructionWithInternalSource. In your model, the only ConstructionWithInternalSource is attached to an InternalMass object. It's possible that that will work if you use radiantLowTVarFlow.setRadiantSurfaceType("AllSurfaces") instead. Otherwise you need to use a ceiling Surface instead of an InternalMass object.

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Asked: 2024-06-21 10:53:32 -0500

Seen: 105 times

Last updated: Jul 03