Temperatures calculated for... (result sets)

[Edin Mer]

I am trying to get the surface condensation potential for a model.

I turned on "Use CD model for glazing systems" under "Therm file options".

After simulation under "Display options" there is: "Show result set": 1) "U-factor results";  2) "CR results".

If I select "CR results" I can see surface condensation potential marked yellow on the model. 

The following is my concern: These two result sets don't have the same temperature distributions over the model (see attached pictures), like the "CR result" doesn't use interior/exterior boundary condition temperatures (Ti=24 degC and To=32 degC) that I have set before. 

What is the difference between these two result sets and why they don't have the same temperature distribution?

Also, I'd like to know what is the difference if I turn on Radiation / Automatic Enclosure Model  or if I leave it off (use simplified model for a boundary condition).

Thank you.

[D. Charlie Curcija/LBNL]

CR model uses local convection and radiation heat transfer model for glazing system, allowing for more accurate local heat transfer results (including temperature). Non-CR model uses average convection and radiation heat transfer, which is inappropriate for accurate temperature calculation in the vicinity of thermal bridges (spacers, etc.), but is appropriate for U-factor calculation, which is averaged quantity by definition. So, short answer is use U-factor results for U-factor calculation and use CR model for temperature distribution prediction.

Aut Enclosure (and Manual Enclosure) model are the most accurate radiation heat transfer models and you should use them whenever possible. NFRC uses black body radiation model on the outdoor side of window due to relatively small effect radiation heat transfer p[lays on outdoor surfaces. For indoor surfaces, it uses Auto enclosure.

Charlie

[Edin Mer]

Thank you very much, Charlie. You were very helpful.

Edin