The discussion revolves around the highest temperature that can be achieved using solar light as an energy source, with considerations for both solar water heaters and the potential use of laser light. Participants explore theoretical limits and practical constraints related to temperature and power.
Participants generally express disagreement regarding the clarity and parameters of the original question. While some acknowledge the theoretical limits of temperature, others challenge the vagueness of the inquiry and its practical implications.
Participants highlight the need for clearer definitions and parameters in discussing temperature limits, as well as the distinction between theoretical and practical considerations in energy extraction.
wdlang said:now in many houses, there are solar water heaters
the problem is that, what is the highest possible temperature reachable using the sunlight?
DaveC426913 said:There is no theoretical upper limit* on the size of a solar collector, though there are myriad practical ones.
*OK, there is. The absolute upper limit would be an elliptical reflector that completely encloses the sun with the sun at one focus and the Earth at the other. It would collect 100% of the output of the sun.
wdlang said:i mean the highest temperature achievable
i do not mean the highest power achievable
phinds said:But the two go together directly and you have set no parameters. It would not take a great deal of power to raise a couple of molecules to a VERY high temperature, but that would be utterly useless for anything practical.
I'm just saying what Dave already said. You're question is too vague to have any meaning.
Ken G said:A passive system, which does nothing but absorb heat, could never reach a temperature above that of the Sun, some 5780 K. But if you take the absorbed energy and extract work from it, you could channel that free energy into as small a system as you like, and get an arbitrarily high T, as has been said.
wdlang said:you are right!