Thread: What's the most efficient Heat to Electricity Conversion?

I'm taking a class on alternative energies, and we haven't gotten this far, but every lecture makes me more and more curious about it, since Heat is the easiest kind of energy to generate.

It depends on where you draw your system boundaries. "Heat to electricity" implies you have already burned your coal or erected your soalr furnace and ignores the cost of mining, health and environmental effects or the cost of manufactuirng the solar furnace and the real estate it requires.

What are your boundaries?

The theoretical best efficiency for extracting work from heat is its Carnot efficiency. It is 1 - Tc/Th, where Tc is the temperature of a cold place you're dumping heat into, and Th is the temperature of a hot place you're extracting heat from.

This is the basis for almost all modern power plants. Coal, Oil, and Nuclear anyway. All power plants which work by making something (usually water) hot anyway.

well i'd have to think that the best way to turn heat into electricity is by running whatever is carrying your thermal energy through a nuclear reactor and then absorbing the produced light with solar pannels, kind of like those theoretical sun balls that one of my favorite radicals imagined that would surround a star with solar pannels.

of course this idea is probably not what you're looking for because you're probably expecting something doable, well in that case i believe that the carnot effecience that numsgil reffered you to is the best option. if using this method, make sure to get tc as close to 0kelvin as possible, when heated the thermal expansion will do work for you. (and interesting point here is because we cannot make anything completely 0kelvin, there is no way at all to achieve 100% effeciency if you involve heat in your form of work done)

Originally Posted by saul

well i'd have to think that the best way to turn heat into electricity is by running whatever is carrying your thermal energy through a nuclear reactor and then absorbing the produced light with solar pannels, kind of like those theoretical sun balls that one of my favorite radicals imagined that would surround a star with solar pannels.

of course this idea is probably not what you're looking for because you're probably expecting something doable, well in that case i believe that the carnot effecience that numsgil reffered you to is the best option. if using this method, make sure to get tc as close to 0kelvin as possible, when heated the thermal expansion will do work for you. (and interesting point here is because we cannot make anything completely 0kelvin, there is no way at all to achieve 100% effeciency if you involve heat in your form of work done)

Trouble is that, as I understand it, solar cells only absorb a very narrow range of light frequencies.

I was asking on another thread about the possibility of finding a substance that only emits a narrow range of heat-related radiation, but the consensus seemed to be that laser mediums were the only things that even got close, and they still put off a lot of their energy in the form of heat anyway.