Critique the Frame section

[Ajaysingh Patil]

Hi, 

I am trying my hand at THERM, and I have tried to create and Calculate the attached frame section with double glazing. Can someone please review it for me and let me know if the set up for calculations is correct? The Glazing system was imported from WINDOW

I am also interested in understanding at what distance should the u-factor surface tag for edge be taken from ? from my understanding, THERM assigns the distance of 150mm from the inside of the glazing cavity and not from the sightline as it is mentioned in NFRC. But please correct me if I am wrong.

[Collin Robinson]

Nice work! Two things I noticed:

1. "SHGC Exterior" u-factor tag was missing from the frame exterior. 

2. Nooks and crannies in the frame cavity less than 5mm should be made with a separate polygon. 

I had some trouble with one of the vertices not meshing so I modified it a bit. See revised attached. I got Uframe= 0.5916, UEdge = 0.2755. Coldest frame temp 5.35°C near node 36141. 

I am not at all expert-class, just checking yours against what I know. 

Best,

Collin

[Robin Mitchell]

Thanks Collin for jumping in to help !

The procedures that Collin raises in terms of how to use THERM are described in the NFRC Simulation Manual

https://cdn.ymaws.com/nfrccommunity.org/resource/resmgr/simmanual/nfrcsim7-jul2024.pdf

It is linked from the THERM documentation page

https://windows.lbl.gov/documentation-therm

Robin

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Robin Mitchell

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

[Ajaysingh Patil]

thank you THERM team and Collin !

I have another small question. I have been reading the NFRC manual. For the edge of the glass/glazing distance the sightline should be considered. I have a case where the spacer is the highest material, and thus the edge of glass distance should be measured from this point. But on the interior side my frame ends 0.7mm before the sightline ( see attached photo ). What should the boundary condition be for this 0.7mm distance ? and also the U-factor surface tag ? I do not see  a mention of such a case in NFRC-100.