Radiators as radiant surfaces (wall)


I have been trying to set up an energy model for thermal comfort in winter. Is there any way to set a (sub) surface on the wall as a radiator? Or is this type of heating system limited to what is available in the HB Radiant HVAC properties component, i.e. floor or ceiling heating?

Hello again, here a follow up.

I have been digging a bit, but cannot find a proper sollution. I know in the HB legacy it is possible to select a “custom radiant surface” as input for HVAC system. With that you can control the “internal source” material. (see picture 1)

In HB 1.6.0 there is no possibility for a custom radiant surface, nor any posibility to set a the controls, instead it seems like I need to put a detailed HVAC system from Ironbug. (see picture 2)

However, when I run the ironbug template for Radiant penels + DOAS it gives me the following error:
** Severe ** [Branch][Hot Water Loop Demand Branch 1][components][0] - Missing required property ‘component_name’.
** Severe ** [Branch][Hot Water Loop Demand Branch 1][components][0] - Missing required property ‘component_object_type’.

These messages are consistent even if I give all components a name. There are no other errors and when I run the model without a detailed Ironbug HVAC system, the entire script runs properly and I get MRT, Top, and PPD results out, which is what I am after. Maybe @chris or @MingboPeng can help me a bit?

PS: The attached Grasshopper file is a simplified version of what I try to achieve.
Radiant panels error.gh (188.2 KB)

Hey @AntonH ,

I would still recommend using the LBT plugin and this is not completely true:

You can change the type of radiant surface (Floors, Ceilings, FloorWithCarpet, CeilingMetalPanel) using the HB Radiant HVAC Properties component. There are also several controls exposed there. However, I understand that the options exposed on these LBT components are a simplification from what we had in Legacy since so many people were setting up radiant system controls that were just not realistic given the construction they were using. You probably know that the best practice for radiant slabs is to cast the temperature sensor into the slab and the controls on the LBT templates are set up this way for the slab options (the metal panel is much simpler).

If you think you know what you’re doing, you can still use Ironbug for radiant systems if you’re using the LBT plugin and I think @MingboPeng could elaborate. You could also always use the OpenStudio SDK to post-process the OSM exported by honeybee and this is the method that would give you the most control over all of the detailed parameters.

Thanks for your answer @chris !

I did indeed find the possibilities as you mentioned for radiant slabs. However, what I am trying to model is radiators under the window, especially for housing (but even for offices) here in Sweden that is the most common practice for a heating system. This means that I want to put the radiant surface inside the wall, as how it was possible in the legacy version.

In the GH file I had attached, I tried making the radiators as surfaces inside the wall and set as with an internal source material on the inside. However, because of the error messages, it also is not possible to export the model to an OSM file, and thus I cannot check it in the Openstudio app.

Hi @AntonH
For this issue, please reference this post: Ironbug HVACTemplate_sys13 - #4 by MingboPeng

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Thanks @MingboPeng ! It works now if I plug in the radiant surface as a floor, but when I model parts of the exterior wall to have a radiator, as pictured below, it does not recognize the small surfaces as radiant surfaces for some reason. It then gives the same error message as before.

I noticed that when giving all surfaces a unique name and link it to the room, it actually takes the radiators now as separate radiant surfaces!

Thanks for the help!

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I discovered a new issue regarding this. I am testing now adding 2 radiators in a single room. Each radiator has their respective unique name, but now the error comes as follows:

Surface RADIANT_CONSTRUCTION_1_D3B2EF09 is referenced by more than one radiant system–this is not allowed.
Surface RADIANT_CONSTRUCTION_2_6808B1C3 is referenced by more than one radiant system–this is not allowed.

So in Ironbug, what I am doing is to have 2 surfaces with 2 hot water loops, combine them with the equipmentgroup component and connect that to the IB_ThermalZones.

I cannot combine the surfaces as they are on different walls.

Is there a way to model 2 radiant surfaces that are connected to the same room?