I have another three questions about theoretical computations in photovoltaics systems. I was wondering if you could help me with. 1-If the module efficiency written in a catalog is 18% and the calculated efficiency for the given module in specific weather conditions is 30%, does the calculated value make sense? 2-Is it possible to obtain negative values in the calculations done for short circuit current? 3-If the negative value is correct for the short-circuit current, according to the formula ( p =I_sc*V_oc*ff) will the output power also be negative? And If a few days of negative power is achieved in a month, how the average power is calculated? Is it ignored or the absolute values are used in the calculation?
The PV efficiency on the name plate is calculated based on STC, so theoretically you should not get more then this value. Short circuit current supposed to be relatively high and positive.
You can read more in the following book:
Al-Waeli, A. H., Kazem, H. A., Chaichan, M. T., & Sopian, K. (2019). Photovoltaic/Thermal (PV/T) Systems: Principles, Design, and Applications. Springer Nature.
Hello Narjes Azizi
1) The module efficiency is usually the max. efficiency you can get from it. Even when we assume that some specific weather condition can help get a better efficiency value, it would be a minor improvement (could not be as much as 30%).
[Edit: By writing "could not as large as 30%," I meant, "it could not be much larger than the specified max. value of 18% that you mentioned"]
2) Maybe you are measuring the current flowing inwards, which explains the negative short circuit current. This current is defined outwards.
3) The power formula you wrote should not give you a negative value, because both Isc and Voc are positive (according to the directions they are defined).
Best regards...
Hello
Dear Hussein A Kazem
thanks for the reference you mentioned and for your answer.
best regards
- Badges
- Science topic