Therm 7.7 & 7.8 Multiple boundary condition issue

yal...@gmail.com

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Jun 7, 2021, 4:00:31 PM6/7/21

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Hi Robin,

In both Therm 7.7.7.0 and 7.8.15 when you select boundary conditions spanning over several materials and double click to assign a u-factor tag the emissivity of the last selected material is applied to all the surfaces resulting in incorrect simulations.

It happens on all files for me and actually ended up being a problem during my NFRC certification as I was unknowingly changing the surface emissivity.

See below materials are top to bottom Aluminum anodized e=0.8, steel sheet galvanized e=0.2, polystyrene e=0.9. Initially all boundaries are assigned correctly.

Issue does not happen with V7.4. I couldn’t see anything on the forums not sure if this is a known issue.

Then I select the bottom BC + SHIFT + DOUBLE CLICK the top boundary. Apply a u-factor tag. Click OK.

Now DOUBLE CLICK the middle boundary and it changes the emissivity. It also simulates this resulting in an incorrect simulation.

Yalin

yal...@gmail.com

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Jun 7, 2021, 4:02:21 PM6/7/21

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Robin Mitchell

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Jun 7, 2021, 6:15:34 PM6/7/21

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Yallin

I can replicate this problem and we will work on a fix for the next version of THERM 7.8, which will hopefully happen relatively soon.

Thanks for finding this problem and documenting it.

Robin

Robin Mitchell

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Jun 25, 2021, 4:56:56 PM6/25/21

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We have fixed this issue and put out a new version of THERM 7.8 (7.8.16) with that fix.