[TRNSYS-users] Long wave radiation and internal convection

[Ivan Flores Abascal]

Dear Sir / Madam:

I would appreciate if you could clarify some doubts about how does  
Type 56 treat the heat exchanged by convection and long wave  
radiation. In the Type 56 user' manual appears:
“The long-wave radiation exchange between the surfaces within the zone  
and the convective heat flux from the inside surfaces to the zone air  
are approximated using the star network given by Seem”...

“The star temperature can be used to calculate a net radiative and  
convective heat flux from the inside wall surface:
Q_comb,s,i = Q_c,s,i + Q_r,s,i = (T_s,i – T_star) / (R_equiv,i • A_s,i)"

I assume that Q_comb,s,i is equal to QCOMI (NTYPE 19). Is it correct?

If h_i is the internal convection coefficient, can I calculate the  
convective heat flux from surface i as:  Q_c,s,i = h_i • A_s,i •  
(T_s,i – T_star) ?

I have solved the radiation exchange by the view factor method and I  
have compared the results with the value obtained as Q_r,s,i = QCOMI –  
Q_c,s,i . The results are quite different so I think that difference  
is not for being an approximate method. Is there anything I  
misunderstood?

Is there any NTYPE to obtain the long wave radiation from a surface  
separately?

Thank you very much for your help

Ivan Flores