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Old   August 2, 2007, 12:29
Default Radiation Model
Nicki Parker
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I'm modelling a room which is cooled by chilled beams. I'm looking at worst case summer. I don't have a Monte Carlo radiation licence, but am thinking about using the discrete transfer model, surface to surface transfer mode, with a gray spectral model. At the window boundary conditions, the boundary is modelled as an opaque wall, with emissivity 1 and diffuse fraction of 1 (in the absence of any better value). Does anyone have any views on the assumptions I've used? Any advice would be greatly appreciated

Thanks in advance,

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Old   August 6, 2007, 18:41
Default Re: Radiation Model
Glenn Horrocks
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Hi Nicki,

When I did some similar work I found the discrete transfer model the best to use.

Do a quick validation case of one plate heating up another plate with an analytical answer to check everything is working before proceeding.

Glenn Horrocks
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Old   August 7, 2007, 09:35
Default Re: Radiation Model
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Dear Nicki,

I would agree with Glenn's advice; however, be careful with a geometry with large aspect ratio. The quality of the DTM solution decreases as aspect ration increases with a fixed number of rays. That is, you ray count must go up as the aspect ratio increases.

Ask your help representative for the radiation report showing this behavior for DTM/MC..

Hope this helps,


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