AirLoopHVAC:DedicatedOutdoorAirSystem does not work with draw through fan placement

asked 2023-04-29 03:44:25 -0500

Keigo's avatar

updated 2023-04-29 07:50:57 -0500

A bug report. AirLoopHVAC:DedicatedOutdoorAirSystem is a relatively new feature and many bugs have been found since its release in v9-2-0. This is another bug.

As the title shows, AirLoopHVAC:DedicatedOutdoorAirSystem does not with draw through fan placement. I reproduced the bug with the ExampleFile SmallOffice_CentralDOAS.idf. The DOAS fan placement of the original idf is blow through i.e.

AirLoopHVAC:OutdoorAirSystem:EquipmentList,
    OA Sys 1 Equipment,      !- Name
    Fan:SystemModel,         !- Component 1 Object Type
    OA Supply Fan,           !- Component 1 Name
    Coil:Heating:Water,      !- Component 2 Object Type
    OA Heating Coil 1,       !- Component 2 Name
    Coil:Cooling:Water,      !- Component 3 Object Type
    OA Cooling Coil 1;       !- Component 3 Name

I changed the order of the equipment as follows. Of course, I changed some Node names accodingly.

AirLoopHVAC:OutdoorAirSystem:EquipmentList,
    OA Sys 1 Equipment,      !- Name
    Coil:Heating:Water,      !- Component 1 Object Type
    OA Heating Coil 1,       !- Component 1 Name
    Coil:Cooling:Water,      !- Component 2 Object Type
    OA Cooling Coil 1,       !- Component 2 Name
    Fan:SystemModel,         !- Component 3 Object Type
    OA Supply Fan;           !- Component 3 Name

After the change, Fan Electricity Rate and Fan Air Mass Flow Rate of OA Supply Fan became 0 throughout the year. The OA Supply Fan is not working. The trouble is that no severe error/warning message is shown in the err file. I think the fan placement of PAU is normally DrawThrough, so some people may have already encountered this bug but may not be aware of it.

image description

The idf files are here for reference (V22-2-0).

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Comments

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Keigo's avatar Keigo  ( 2023-05-02 20:09:45 -0500 )edit