"Induced Air Outlet Port List" for Return Plenum

asked 2015-05-19 22:07:18 -0600

TiejunWu

563 ●1 ●8 http://www.carrier.com/

updated 2015-11-10 21:32:07 -0600

__AmirRoth__

4446 ●5 ●17 http://bleedinggreenna...

In OpenStudio, after I define a return plenum, there appears to be a "Induced Air Outlet Port List" for the "OS:AirLoopHVAC:ReturnPlenum" and it has a drop down list of Port List 1 to Port List 12. I suppose it is for the secondary inlet nodes of fan powered mixing boxes(PIU), however I am not sure how to use this.

On the other hand, when I use either series or parallel PIU, I have no way to specify its secondary air inlet node in OpenStudio user interface.

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answered 2015-05-21 10:11:47 -0600

Kyle Benne
6047 ●4 ●9 https://www.openstudio.net/

When you add a PIU terminal to a zone's air inlet node, the PIU secondary air inlet will automatically be connected to the zone's exhaust node. Whether you do this graphically in the OpenStudio Application, or programmatically through the API, it comes down to a call to the addToNode method which has the smarts to make this happen.

The "Induced Air Outlet Port List" displayed for the plenum is a crack in the Matrix. That property really should be hidden because connecting to the plenum in this way is not officially supported by the OpenStudio API.

You might be interested in this post about ports and nodes. https://unmethours.com/question/8041/...

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Can we specify the secondary air inlet not automatically set? No APIs open for this operation.

zhengangzhu ( 2015-05-27 01:21:37 -0600 )edit

The short answer is no. There is no supported API to connect to the Induced Air Outlet Node of the return plenum, short of an EnergyPlus Measure.

Kyle Benne ( 2015-05-27 09:12:25 -0600 )edit

In EnergyPlus there are two types of terminals designed to work with the induced air node. They are AirTerminal:SingleDuct:SeriesPIU:Reheat and AirTerminal:SingleDuct:ParallelPIU:Reheat. If you were really industrious and poked around in OS source code you might stumble on ::setInducedAirPlenumZone, however this method is private and not yet supported publicly, or even accessible from the Ruby API.

Kyle Benne ( 2015-05-27 09:14:42 -0600 )edit

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answered 2015-05-20 14:53:32 -0600

David Goldwasser

20415 ●94 ●14 http://www.openstudio.net/

You are correct. Looking at the EnergyPlus documentation it is for the secondary inlet node for PIU units.

For reference here is a link to OpenStudio's plenum documentation.

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David,

Thanks for confirming this. So the "Port List" should correspond to an EnergyPlus "Node list", however, I do not find a place in OpenStudio that I can assign nodes to each "Port List". Also, in the OpenStudio user interface for PIUs, I do not see a place that I can specify where the secondary air come from (Option 1. Return plenum.Option 2. Zone). From the exported IDF file, looks like its always from the zone.