Model Radiant Panel that only covers part of a Surface

[TiejunWu]

Issue overview

Currently in EnergyPlus, to model a suspended Radiant Panel that only covers part of the ceiling, EnergyPlus modeler need to physically separate the ceiling surface into two geometric surfaces, one part is the ceiling surface with no radiant panel attached and the other part is the ceiling surface that is covered by the suspended radiant panel. For convenience of modeling such a configuration, is it possible for user to specify the percentage of ceiling surface that is used as a radiant surface? For example, in the ZoneHVAC:LowTemperatureRadiant:SurfaceGroup object, for each surface specified, add a field named “FractionOfSurfaceUsedAsRadiantSurface” and set the default to 1.0. Then in the heat balance calculation, automatically break the surface area into two parts based on this input fraction.

In addition radiant panel systems must currently be modeled as an integral part of the floor assembly above the space. In practice radiant panel devices are separate from and suspended from the ceiling with an air gap between the panel and the floor/ceiling assembly. Is it possible to devise a modeling approach that does not require the radiant panel to artificially integrated into the floor/ceiling assembly?

Background information:

Suspended Radiant Panel is commonly used for retrofit or new construction; the panels usually come in prefabricated sizes and would typically only cover part of the ceiling surface. Many high performance building projects are applying Radiant Panel systems as a tactic to improve building energy performance and occupant comfort. This proposed feature could support wider evaluation and adoption of this high performance system.

Reference Link:

https://radiantcooling.com/portfolio-items/clarum-homes-office/ In this office building, half of the ceiling area is covered by radiant panels. (3200 sqft radiant panel, 6400 sqft ceiling)

Details

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• Platform (Operating system, version)
• Version of EnergyPlus (if using an intermediate build, include SHA)
• Unmethours link or helpdesk ticket number

Checklist

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• [ ] Defect file added (list location of defect file here)
• [ ] Ticket added to Pivotal for defect (development team task)
• [ ] Pull request created (the pull request will have additional tasks related to reviewing changes that fix this defect)

[RKStrand]

@TiejunWu This is a great idea for a new feature. The deadline for submitting those to NREL is today so if you want to see this prioritized and possibly worked on in the next year, I highly recommend doing that if you haven't already.