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Now unplug the solar cell.
What happens with the "electric" part of the incoming energy?
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2. The "electric" part is absorbed as additional heat - which means the cell will be crazy hot. Because of the energy sum it will be hotter than fully loaded cell (short circuit with maximum ohmic loses).
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Even if the electricity continues to be generated, physics "almost" dictates it will be no more heat than "normal" defining normal as the heat that is generated by your
typical black-tar roof tiles without solar panels on top.
("almost" because black-tar tile is not a perfect "black body", it does reflect some light)
The electrical energy the solar panel outputs is converted from the energy of the light falling on it. Black-tar tile is rather "light absorbing." It doesn't reflect much. So black-tar tiles pretty much convert all the light to heat. Even if the solar panel converts that energy into electrical to drive a heater, it
would not be more energy than what fell onto it as light so the electrical heat energy would not be more than a direct black-tile converted heat. It
could be more concentrated (say electrical energy driving a high temperature coil heater coming out of a small nozzle), but total energy would be at best the same amount as the energy carried by the light coming in. When the waste-energy is spread and dissipate over the
entire area of the panel, you have at worst (hottest) same as black roof tiles.
Now, if you used to have white tile on your roof a lot more energy was reflected away, it would be cooler than black roof tiles. So un-plugged solar panel under the sun would be hotter than the white tiled roof, but not much hotter than the black tiled roof if hotter at all.