[TRNSYS-users] TYPE 80

[David BRADLEY]

Christian,
   It sounds as though the connection from Type80 to Type56 is correct 
(in TRNBuild, you indicate that the outside convection coefficient for a 
wall should be an INPUT and you give the input a name such as HBACK3, 
then you connect some model to the new Type56 input). You might need to 
have a look at the inputs to Type80, however. Type80 takes the surface 
temperature and the surrounding air temperature and computes a 
convective energy transfer coefficient so you would need to go back in 
to TRNBuild and add an output for the outside surface temperature of 
your wall, then pass the new Type56 output to Type80. You can repeat the 
process with multiple instances of Type80, one for each of your 
different surfaces.

   A word of caution, however! Type80 computes a convection coefficient 
based on that natural convection dominates. On outside surfaces, forced 
convection from the wind almost always dominates the heat transfer. You 
might be better served finding a correlation that computes a forced 
convection coefficient instead.
Best,
  David


On 8/23/2013 06:52, Brembilla Christian wrote:
> Dear All,
>
> I have a problem with TYPE 80. I would like to see the /convective 
> coefficient/ /for/ *back side* of surface change in time.
>
> I tried to set TYPE 80, I started in TRNBuild and I chose the INPUT 
> /keyword /, HBACK3, then in Simulation studio I connected TYPE 80 
> /Convective coefficient for back side of surface /with TYPE 56 HBACK3, 
> and them I plot it.
>
> When I run the simulation the convective coefficientfor *back 
> side* starts from 0 and it remains always constant at a about 9.5. I 
> done the same thing with VERTICAL and the result does not change.
>
> I can set the /convective coefficient//for/*front side *of surface 
> with TRNBuild chosing internal calculation.
>
> Questions:
>
> -someone could explain me how to use INPUT especially the difference 
> between HBACK3 and VERTICAL.
>
> -how select a proper surface, for instance I would like to see the 
> convective coefficient for the surface facing to the south, for the 
> surface facing to the north and so on.
>
> Regards
>
> Christian
>
>
> _______________________________________________
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> TRNSYS-users at cae.wisc.edu
> https://mailman.cae.wisc.edu/listinfo/trnsys-users

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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