which of the following actions are likely to cause the excessive heating of the solar panels when they are in operation ?
one such reason can be the absorption of the wavelengths below the bandgap which presumably contribute mainly for thermal vibrations. Another is the fact that not all the photons absorbed have the energy that match perfectly with the bandgap. some photons (in the shorter wavelength region) have more energy than required for the electron transition from valance band to conduction band, so I guess the balance would be dissipated as heat. Which of these two are dominant in a solar cell, or is it something entirely different that cause the solar cells to heat up.
the two facts induce heating of the solar cell especially under high concentration
Apart from the reasons mentioned by you there are some other reasons for the heat produced.The series resistance may be one of the reasons as the non barrier reason has always some resistance. In case of amorphous silicon solar cells it is quite high as amorphous semiconductors have high resistivity as compared to their crystalline counterpart due to low mobility of charge carrier.
All the cited reasons contribute to increase temperature of solar cells. the most important are infrared wavelength which are present in the solar spectrum. One of the difficulty is how to eliminate these kind of radiation which are harmful in the operation of solar cells.
I agree with all that has been said considering the fact that solar energy consists of both solar heat and solar light. IR consists of about 49% of the solar spectrum, visible is about 46 and UV is about 5%. I think it is more of the photons absorbed which are not converted to electricity but to heat since there are more of these.
Thank you all for your answers. I was wondering if one mechanism is clearly dominant over the other? Does the dominant mechanism depend on the type of solar cell? Any suggestion on published literature on this topic would be greatly appreciated.
I think thermalisation (for photons with higher energy than bandgap) is the predominant mechanism.
The basic fact is that most of the incident solar energy upon any solar cell, which is not converted to electric energy, will end up as heat energy. The band gap plays a role, but not much. Solar cell efficiency is less than 25%, unless concentrators are used. So, most of the 75% or more of the incident energy ends up as heat energy. Most of the heat energy is due to the low energy photons; hence, a low band gap solar cell, or a high band gap solar cell, or a metal does not make a great deal of difference.
some photons are reflected, others are oculated vy front grid, others are not collected, all of these and others factors reduce solar cell efficiency nad do'nt create heat?
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