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How to model ceiling radiant panels?

asked 2015-01-11 10:28:09 -0500

updated 2015-11-12 15:29:51 -0500

Hello All, Is there any way to model radiant panels (see attached picture) in ceilings by using Design builder or EnergyPlus? Can you please share your experience? Do I have to add nodes as we do for other HVAC systems? Also, these radiant panels will get hot water from a biomass boiler, can I model biomass boiler in Design Builder?

Thanks

Kindest regards

Waseem

Radiant panels in ceilings

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answered 2015-01-11 11:27:48 -0500

updated 2015-01-11 11:30:47 -0500

In EnergyPlus the system you describe can be modeled with the ZoneHVAC:LowTemperatureRadiant:VariableFlow (or :ConstantFlow) object. This object will reference heating/cooling coils which are attached to their respective plant loop demand branches with nodes as any hydronic coil would. It will also reference a surface or list of surface which define where in the space the panel is located (in this case, a ceiling surface). This surface must have a construction of the type Construction:InternalSource, which defines the material makeup of the panel as well as the dimensions of the tubes.

There is no explicit way of modeling biomass boilers in EnergyPlus that I'm aware of.

PS. This question did not specify OpenStudio, but for the record here is a good video explaining modeling and calibrating these systems in OpenStudio: http://youtu.be/6vMBXIM_yjU

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Is there anything different about a biomass boiler than a regular boiler, other than the fuel source?

Benjamin gravatar imageBenjamin ( 2015-01-12 08:07:04 -0500 )edit

@Benjamin not that I know of, but someone else might know better. Should have said 'biomass is not a fuel source available to the EnergyPlus boiler object'. Shouldn't be too hard to post-process aggregate fuel consumption using manufacturer data, and assuming similar operation with the modeled boiler, or just a District Heating source.

Eric Ringold gravatar imageEric Ringold ( 2015-01-12 08:41:25 -0500 )edit

Thanks both, I will look into it. One other thing, the inlet temperature into the panels in my case is around 80 C, will this be LowTemperatureRadiant system or HighTemperatureRadiant. Also, will this Construction:InternalSource will account for cooper tubing, Aluminium panel as materials?

Thanks Kindest Regards Waseem

Waseem gravatar imageWaseem ( 2015-01-12 12:11:49 -0500 )edit

If you look at the EnergyPlus InputOutput reference for HighTemperatureRadiant, you'll see "The high temperature radiant system (gas-fired or electric) is a component of zone equipment that is intended to model any “high temperature” or “high intensity” radiant system where electric resistance or gas-fired combustion heating is used to supply energy (heat) to a building occupants directly as well as the building surfaces (wall, ceiling, or floor)." That model does not attach to a plant hydronic loop, and so is probably not appropriate to what you're trying to model.

Eric Ringold gravatar imageEric Ringold ( 2015-01-12 13:11:32 -0500 )edit

InternalSource construction will account for any material layers you define. Be careful though, if your construction has too high a thermal conductance for the thickness, EnergyPlus will throw an error. It's really useful to read the Engineering reference for how this radiant system simulation works, perform sensitivity analyses of how different constructions affect the performance of the system, and apply engineering judgement. Your simulated construction layers might not be 1:1 with reality.

Eric Ringold gravatar imageEric Ringold ( 2015-01-12 13:15:37 -0500 )edit

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Asked: 2015-01-11 10:28:09 -0500

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Last updated: Jan 11 '15