Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question

Dilemma combining AirflowNetwork with a zone plenum in EnergyPlus IDF?

asked 2023-05-05 17:35:07 -0500

bhonz's avatar

updated 2023-05-07 07:12:52 -0500

I am beginning to learn EnergyPlus by building up an IDF model base on my single-family residence. I had the model functioning satisfactorily with an AirLoopHVAC:ReturnPlenum but now need to add AirflowNetwork components to it. After working out the severe errors to the point of it beginning the first day's warm-up simulation, I hit an apparent roadblock involving the plenum zone node. AirflowNetwork seems to demand that node be represented as a Distribution:Node, and the latter entered into the linkage chain. Once done, I get the single error that says the Component Name in the Distribution:Node definition is not found in the AirLoopHVAC. If it can't be found, it shouldn't need to be included!

After thoroughly checking the IDF for errors, I looked for examples of similar for some guidance, but found none that included the combination of an AirflowNetwork with a zone plenum. The documentation files provided no help on the issue either. Online, I found practically nothing, except one 2013 dissertation that seemed to imply it used both simultaneously. And then a 12/10/22 unanswered request for help on UnmetHours by harjmand, "Airflow network with distribution results!". My issue is not the same as harjmand's but he/she seems to have gone beyond my roadblock somehow. I am looking for some example using both an AirflowNetwork and a zone plenum (preferred), or other insight that might show me a way out of this circular errors situation. Thanks.

edit retag flag offensive close merge delete


After trying all kinds of work-arounds I can think of to satisfy the AirflowNetwork's demand that the Plenum zone node be defined, yet when it is defined it cannot find the AirLoopHVAC reference (though it appears in the BND), I am coming to the conclusion that a zone plenum is incompatible with AirflowNetwork Distribution. If someone can confirm this or show how it can be achieved, this case can be closed.

bhonz's avatar bhonz  ( 2023-05-19 19:41:38 -0500 )edit

1 Answer

Sort by ยป oldest newest most voted

answered 2023-05-13 22:27:53 -0500

matbla's avatar

Hi Bhonz,

I have a 'work in progress' residential MVHR system which includes a return plenum. The system was created in Designbuilder detailed HVAC, but the idf text is perhaps helpful for you. I have uploaded the HVAC system idf text here.

Note, this system is still WIP as it has an unsolved query on it here, however the return plenum is functioning as intended/expected.

Some notes on the system, to help make sense of it;

  • This system is for a single apartment, 3 supply zones (lvgktn, bed1, bed2), and a single return zone plenum (bathroom).
  • There is a hallway in the apartment layout which in reality functions as a transfer zone. However, It is an internal zone, and I ignored it, assuming air passes in and out equally such that it is neutral in ventilation thermal loads.

  • There is a radiant panel heater on the living kitchen only (Passive House design, and heater was allowed for in the design for that zone only, rather than in duct heating). The heater is not used in the system, i.e. heating schedule was turned to off 24/7 to test hours below temp that the HR can achieve alone.

  • All three supply zones have cooling setpoint at 22C, which, without active cooling in the system acts to control the summer boost bypass (economiser+HR bypass function).

Hope this helps.

edit flag offensive delete link more



Thanks, Matbla

My problem is specific to combining a plenum object with an AirflowNetwork analysis, and more specifically with the Distribution aspect of the AirflowNetwork model, not with air flows in general. I do have the plenum working with AirLoopHVAC analysis. I don't see that your IDF includes any AirflowNetwork content. But thanks anyway for your kind response. - Bhonz

bhonz's avatar bhonz  ( 2023-05-14 08:37:33 -0500 )edit

Interesting, what is your application of AFN that needs a return plenum?

matbla's avatar matbla  ( 2023-05-14 15:19:14 -0500 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Training Workshops


Question Tools

1 follower


Asked: 2023-05-05 17:35:07 -0500

Seen: 57 times

Last updated: May 13 '23