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> No matter how big you build the heliostat, the best you can do is bring the thing it's heating into thermal equilibrium with the sun. Its temperature will nev
by murderfs 4y ago
> No matter how big you build the heliostat, the best you can do is bring the thing it's heating into thermal equilibrium with the sun. Its temperature will never exceed the temperature of the sun.
If you build it large enough, though, it'll raise the temperature of the sun!
- mrob 4y agoOnly if you add a heat source on the earth side that's hotter than the sun. All a solar concentrater does is increase the rate of energy transfer between the object being heated and the sun. The hot side gets colder and the cold side gets hotter. The only thing driving this energy transfer is the temperature difference, so once the temperatures are equal there is no more energy transfer. If you make it really huge, the temperatures equalize faster. This can increase the equilibrium temperature of the object because it's also losing heat to its environment. Bigger mirrors push the equilibrium temperature closer to the temperature of the sun, but never exceed it. It doesn't matter that the mirrors focus the radiation, because mirrors are not directional. They work equally well to transfer energy from the object to the sun if the object happens to be hotter. Whoever downvoted me doesn't understand thermodynamics.
- murderfs 4y agoThe sun's temperature is not fixed, it's the equilibrium temperature between the energy generated by internal fusion and the energy that escapes via radiation. If you build mirrors that reflect an appreciable amount of the sun's radiation back to the sun, its temperature will rise.