[TRNSYS-users] Ground back heat transfer coefficient

David Bradley bradley at tess-inc.com
Fri Aug 22 11:13:25 PDT 2008


Nalin,
A very large value of convection coefficient indicates that there is a 
high level of coupling between the boundary temperature and the outside 
surface temperature. A value less than 0.001 indicates that there is 
direct contact (ie no temperature difference at all) between the surface 
and the boundary temperature. If your high value is high enough, then in 
effect you have direct coupling. If you choose a small but not too small 
coupling value (0.1 for example), you may see some difference.
Kind regards,
David


NALIN SWAROOP wrote:
> hello all
>
> Why does trnsys gives a very large default value(999) to the back heat
> transfer coefficient of the ground layer?what does large value signify?
> and as  ground is defined as the boundary should'nt just the boundary
> temp. value a sufficent input??
>
> I have kept the value to be small(<.001) and large (1000) but there are no
> changes in the results.
>
> TIA
>
> Nalin Swaroop
>
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>
>   

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