Conversion of heat energy directly into electricity?

Question

Is there a system or process that will convert heat energy directly into usable electricity?

Answer 1

yes, every power company does that.

Answer 2

Man Ive thought of this too.  If there was a system that would convert heat to electricity at room temp global warming would be solved!!  No there isnt!

Answer 3

A thermocouple does just that.  When two dissimilar metals are joined and then heated they produce an electric current.

This is sometimes used to power controls on furnaces and water heaters.

Answer 4

There is no "direct" way of making electricity from heat, the heat has to drive a generator which in turn makes the electricity.

Answer 5

Stirling engines will.   Google it.   They can turn a (very small) flywheel on the temperature difference between your hand and room temperature.   The available energy between two temperatures is pretty small unless the difference is large.  A  500 degree difference is needed to make the engine economical.   That doesn't have to be 500 above air temperature though.   Liquefied natural gas is around -200'.   Combine this with a small heat source and the difference would produce power.

Answer 6

Usually this type of conversion is done with water being turned into steam, which turns a turbine, which runs a generator.

Seebeck voltage is more likely used to measure temperature--it's really not efficient enough to produce useable current.

Answer 7

You're thinking about this the wrong way.  What you see as "heat" is a by-product of a chemical reaction.  Chemical reactions are in essence the transfer of electrons.  Transfer of electrons is electricity.  What you want to do is extract the current flow (i.e., transfer of electrons) from chemical reactions without generating heat (which we now turn into steam to turn a generator to generate electricity).  

Happily, the answer to this question is that there is already a way to extract the current from a chemical reaction.  Google "fuel cell" for more details.

Answer 8

heat makes steam makes a turbine move makes electricity

Answer 9

The Seebeck effect can be used to generate electrical voltage by heating the junction of two dissimilar metals. I don't think it is terribly efficient but is used in the plutonium generators you mentioned.