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AirTerminal:SingleDuct:SeriesPIU:Reheat not being assigned a secondary air inlet node

asked 2020-05-07 09:37:22 -0600

jugonzal07's avatar

updated 2020-05-07 15:48:43 -0600

Hi all,

I'm working to add AirTerminal:SingleDuct:SeriesPIU:Reheat to my workflow and am running into an issue with the "Secondary Air Inlet Node" parameter remaining blank even when adding a zone to its respective demand side branch when using the OpenStudio SDK (2.9.1).

My workflow has been the following for adding zones. I first create the supply side of the AirLoopHVAC and assign the air terminal I want in the supply side. From the GUI's perspective, this is how it would look when adding aAirTerminal:SingleDuct:SeriesPIU:Reheat:

Airloop without zone

However, even after adding a zone to this airloop's demand side using


this AirTerminal:SingleDuct:SeriesPIU:Reheat's "Secondary Air Inlet Node" is still blank. Interestingly enough though, if I make this a multizone system, and add another zone to using the same airloop_hvac.multiAddBranchForZone(zone) call, this second terminal DOES have a populated "Secondary Air Inlet Node" (it's the zone's return air node).

image description

The main questions to answer are:

  • Is there a way to manually set the "Secondary Air Inlet Node" for an AirTerminal:SingleDuct:SeriesPIU:Reheat object?
  • If not, is this implementation for adding zones to terminals on the demand side of an air loop incorrect or bad practice?

OSM files containing the scenarios from the images above can be found here

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answered 2020-05-12 11:20:43 -0600

updated 2020-05-14 06:16:22 -0600

You should call addBranchForZone(Model&, HVACComponent& atu) instead. This is a known bug cf OpenStudio#2023

[1] OpenStudio-PAT(main)> m =; z =; a =; c =; fan =; atu =, fan, c);
[2] OpenStudio-PAT(main)> a.multiAddBranchForZone(z, atu) # or a.addBranchForZone(z, atu)
=> true
[3] OpenStudio-PAT(main)> puts atu
  {b5c222b7-ca79-41c7-8521-3f524e131e93}, !- Handle
  Air Terminal Single Duct Series PIU Reheat 1, !- Name
  ,                                       !- Availability Schedule Name
  autosize,                               !- Maximum Air Flow Rate {m3/s}
  autosize,                               !- Maximum Primary Air Flow Rate {m3/s}
  autosize,                               !- Minimum Primary Air Flow Fraction
  {cd4e2d2f-3b79-4df3-8891-68f67d55c5ab}, !- Supply Air Inlet Node
  {c9e506f7-f556-4c32-869a-8ca153044dbc}, !- Secondary Air Inlet Node
  {d361476e-9149-439e-b96f-708cc63df0e8}, !- Outlet Node
  ,                                       !- Reheat Coil Air Inlet Node
  ,                                       !- Zone Mixer Name
  {fc792d34-967a-45a2-84d4-723347679657}, !- Fan Name
  {c25187dc-a753-4f97-a78c-ee26673b8efa}, !- Reheat Coil Name
  autosize,                               !- Maximum Hot Water or Steam Flow Rate {m3/s}
  0,                                      !- Minimum Hot Water or Steam Flow Rate {m3/s}
  0.001;                                  !- Convergence Tolerance
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Asked: 2020-05-07 09:37:22 -0600

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Last updated: May 14 '20