U-factor defined but no U-factor results

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Sven Oxtoby

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Mar 1, 2022, 3:21:11 AM3/1/22
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Hi

Can anyone figure out why I get no U-factor results from the attached model? Exporting to .txt also yields nothing.

 The simulation does run.

detail-A_Rev1_ins-glazing2_blank-U-factors.png

Therm 7.7.12.0

Thanks!
Sven


detail-A_Rev1_ins-glazing2.THM

Sven Oxtoby

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Mar 1, 2022, 11:31:26 AM3/1/22
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I got it to work after tweaking a bunch of things at once (as I had a couple of problems to solve), but I'd still be interested to know if anyone knows what sort of problem causes this symptom.

I found one surface of a cavity that had somehow been assigned the interior frame BC (such BC should only be used for surfaces exposed to the indoor air). So perhaps that was the problem.
I also found that I had some frame cavities set to a frame cavity material I had created (custom), so perhaps I had done something wrong there, although as far as I could see, I had set the properties the same as for the NFRC 100 cavity type.

Robin Mitchell

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Mar 1, 2022, 2:47:33 PM3/1/22
to Sven Oxtoby, THERM
You need to assign U-factor tags to the boundary conditions where you want U-factors calculated. 

See the NFRC Simulation Manual, chapter 6.5: Defining Boundary Conditions, starting on page 6-29, and look at the diagram on page 6-32

Here is a link to the THERM Documentation page where it is linked

Here is a direct link to the manual

Robin


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Robin Mitchell
Building Technology and Urban Systems Division
Energy Technologies Area
Lawrence Berkeley National Laboratory

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