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Problem with modeling the InletSideMixer AirTerminal with a FCU ZoneHVAC in OpenStudio

asked 2017-08-31 09:25:38 -0500

edixon16's avatar

updated 2018-04-03 11:10:10 -0500

I am trying to model a DOAS FCU system that delivers condition OA from the DOAS to the FCU terminal unit before it is delivered to the zone. There is an AirTerminal:SingleDuct:InletSideMixer object in OS that I think would be the valid choice of air terminals for this system, however, when I assign both this object as well as the ZoneHVAC:FourPipeFanCoil object to the same zone I end up getting the error at the bottom of this post when trying to simulate the model. It appears that OS is not connecting the InletSideMixer to the ZoneHVAC system. I have tried arranging the equipment in the OS Thermal Zone tab with the AirTerminal object before the ZoneHVAC object and vice versa, both resulting in the same error. Am I modeling this system incorrectly, or is this an oversight with the OS software? I am running OS v2.1.

* Severe * IP: IDF line~1442 Error detected in Object=AIRTERMINAL:SINGLEDUCT:MIXER, name=INLET SIDE MIXER * ~~~ * Field [ZoneHVAC Unit Object Name] is required but was blank
*** IDF Context for following error/warning message:
*** Note -- lines truncated at 300 characters, if necessary...
*** 1439 AirTerminal:SingleDuct:Mixer,
*** indicated Name=Inlet Side Mixer *** Only last 6 lines before error line shown.....
*** 1440 Inlet Side Mixer, !- Name
*** 1441 , !- ZoneHVAC Unit Object Type
*** 1442 , !- ZoneHVAC Unit Object Name
*** 1443 Node 1, !- Mixer Outlet Node Name
*** 1444 Node 3, !- Mixer Primary Air Inlet Node Name
*** 1445 , !- Mixer Secondary Air Inlet Node Name * Severe * IP: IDF line~1445 Error detected in Object=AIRTERMINAL:SINGLEDUCT:MIXER, name=INLET SIDE MIXER * ~~~ * Field [Mixer Secondary Air Inlet Node Name] is required but was blank * Severe * IP: Blank "required" fields found in input * Severe * IP: Out of "range" values and/or blank required fields found in input * Fatal * IP: Errors occurred on processing IDF file. Preceding condition(s) cause termination.

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answered 2017-08-31 11:04:00 -0500

Try adding the FCU from the My Model sub-tab to the demand side of the air loop between the AirTerminalSingleDuctInletSideMixer and the ThermalZone.

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This did the trick! Thanks! I was not aware that zone HVAC equipment could be placed on the air loop. Is the inlet side mixer the only terminal unit that allows this? It appears that there is no supply side mixer that would allow for placing the zone HVAC equipment between the ZoneSplitter and the AirTerminal objects.

edixon16's avatar edixon16  ( 2017-08-31 13:49:48 -0500 )edit

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Asked: 2017-08-31 09:25:38 -0500

Seen: 182 times

Last updated: Aug 31 '17