[TRNSYS-users] Front side Boundary condition

Tue Aug 2 07:36:40 PDT 2011

Luis,
  I think the idea is that Type56 is calculating the effects of what 
happens in the zone being modeled. The front side of the wall is inside 
the zone so Type56 is going to calculate the air temperature, the wall 
surface temperature, and (if you allow it to) the convection coefficient 
between the air and wall. If you are trying to model a surface in your 
zone that is always at some known temperature then I think you are 
correct that the best way to model it would be to specify a back-side 
temperature in direct contact with a low-mass "wall." I would allow 
Type56 to calculate the convection coefficient between your surface and 
the zone air temperature since this convection coefficient is dependent 
on both the magnitude and the "direction" of the temperature difference.
Best,
  David

On 8/2/2011 03:47, Claros Marfil, Luis Jesus wrote:
>
> Hi Trnsys Users,
>
> I would like to know if it is possible to define a boundary value for 
> the FRONT SIDE of a wall directly. In page 6-103 (Type 56 - TRNSYS 16 
> Manual) it is said that : "/Normally, the boundary condition is the 
> temperature of a node connected to the back surface of the wall 
> through a pure resistance. It is possible to specify the surface 
> temperature of the outside by setting the back side heat transfer 
> coefficient of the WALL TYPE to a very small value (less than 0.001 
> kJ/h/m2)./
>
> So, I understand that if a coefficient with a value of  0,001 kJ/h/m2 
> or lower is used, the boundary temperature corresponds to the back 
> side, and the only way I find to "transform" this back side 
> temperature into a front side temperature is using a very-low 
> resistance (massless layer) by using a high convective heat transfer 
> coefficient in the front side.
>
> Any idea would be highly appreciated.
>
> Thanks,
>
> *Luis J. Claros Marfil*
>
> Grupo de Materiales Avanzados - Advanced Materials Group
>
> Centro Tecnológico I+D+i  - R & D Technology Center
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> *ACCIONA Infraestructuras
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David BRADLEY
Principal
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