[TRNSYS-users] Convection Model in photovoltaitic panel

[Diego A. Arias]

Dear Javier,

Please refer to the mathematical description of the PV cells modeled in 
TRNSYS (Volume 5, 'Mathematical Reference', section 5.2.5).  
Specifically, section 5.2.5.5. describes how the temperature of the cell 
is calculated.  As a brief description, the temperature of the cell is 
the result of an energy balance on the photo voltaic cell.  Assuming 
that the ratio between the transmittance-absorptance product to the 
overall heat transfer coefficient ( (tau -alpha) / U_L) is constant, the 
plate temperature is calculated using the result of this product at test 
conditions (Normal Operating Cell Temperature).
For a more complete description of this model, I recommend that you look 
at 'Duffie and Beckman, Solar Engineering of Thermal Processes, John 
Wiley & Sons, 1991', section 23.3.
You could modify Type94 and improve the afore mentioned assumption, by 
calculating the heat transfer coefficient from a rectangular plate under 
wind conditions. The same book, in section 3.15, gives different Nusselt 
number correlations for plates exposed to outside winds.
Please let me know if this helps or if you need additional information.
Best regards,

Diego


javier mota wrote:

> Halo;
> I am Javier Mota fron 3i-ingenieria, madrid
> We are using the phtovoltaitic models in TRNSYS to simulate 
> photovoltaitic centrals.
> But we are asking ourselves, so I ask to anybody may help us, what is 
> the model the panels work with in relation with the convection, to 
> disipate heat.
> It would be posible that the place we will install the panels,  a big 
> central with tracking in two axis,
> would have important wind and maybe cold wind,...so the disipationl of 
> heat would cause the panels got colder and as i have seen, with less 
> temperature,  more production of energy, OK?
> So what is the model in TRNSYS models to disipate heat, and how could 
> I consider this phenomena.
> Thanks in advance
>
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