[TRNSYS-users] Solar collectors

David Bradley bradley at tess-inc.com
Thu Feb 25 08:18:44 PST 2010


Matteo,
  The Type1 collector area is the /total/ array area, not the module 
area nor the parallel area. So it should be set to 12.
> And moreover, I'm takin the intercept efficiency, efficiency slope and
> efficiency curvature, in a datasheet. The values are:
> n0: 0.8
> a1: 5.9 W/(m^2K)
> a2: 0.03 W/(m^2K^2)
>
> Should I use them as they are in the trnsys relative parameter or do i
> have to correct them? (I know that I have to change the unit
> measurement...)
>   
I'm not sure I understand what you mean about relative parameters. The 
sign of the parameters is typically built into the model so you provide 
positive values and the model knows that the form of the equation is

n0 - a1*(Ti-Ta)/Gt - a2*(Ti-Ta)^2/Gt.

The one thing you must be careful about is that standards for the 
efficiency equation differ. Sometimes efficiency is based on T inlet 
minus T ambient. In other countries it is T average minus T ambient. 
Check the "More" button next to each parameter and you'll get additional 
information about specifically what the parameter is intended to do and 
what assumptions are being made.
Best,
 David


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Thermal Energy System Specialists (TESS), LLC 
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