How exactly is HEAT harnessed, in order to produce Electricity?

Answer 1

All electricity producting plants except for the renewable sources produces heat from coal, oil, gas, geothermal, or nuclear fuels. In these cases, the heat is used to boil water to produce steam. The upward motion of the steam provides the energy to turn turbines which is attached to electricity generators. Generators basically are a big magnet within a coil of wires. When you spin a magnet within a coil of wires, the change in flux of the magnetic fields induces electrons to flow within the wire in a certain direction, thus producing electricity.

Answer 2

Aside from steam turbines, there are Stirling engines. In a Stirling engine, heat is used to expand a working fluid like air or helium in order to drive a sealed piston. The working fluid must be cooled on the other side of the cylinder so the difference between the high and low temperature drives efficiency. Stirling engines can be used with virtually any heat source, including the sun.

For a more thorough explanation, try here:
http://www.infiniacorp.com/technology/how_stirling_works.htm

Another way is through a solid-state (semiconductor) device called a thermo-electric generator, which uses a temperature differential to produce a voltage. These are how most deep space probes are currently powered (heat comes from plutonium).

Answer 3

Contrary to some other posts, Stirling engines (are cute and all, but) are not used for generating electricity on any large scale. And steam does "rise" through the turbines.

High pressure steam is generated by burning coal or fuel oil or by nuclear reaction That is on one side (the high-pressure side) of a turbine (think air plane jet engine). On the other (low-pressure) side is a "condenser" in which the steam pipes are cooled by river water, the ocean or the air. That is the big tower by a nuke plant. The reactor itself is in the small dome.

Steam condenses into liquid water which is vastly small in volume and that water is pumped up to a high pressure back to the boiler or reactor heat exchanger.

The pressure difference across the turbine makes it spin. Very fast and with a lot of torque. Enough to spin electrical generators which are somewhat like the alternator in your car, but the size of a smallish house.

Other working fluilds, like freons, or even other technologies, like thermocouples, could be used for unusual applications. But 99% of electrical power generated from heat is through a steam-powered turbine.

Answer 4

You basically have to move a wire through a magnetic field. That is what moves the electrons, which are of course what produces electricity.

Heat is used to turn water into steam which makes the turbines move. That is what moves the magnets.

Flowing water accomplishes the same thing. That is hydroelectric.

-Dio

Answer 5

usually as a generator (steam).

Nuclear plants produce high powered steam... rising steam turns a turbine, and that turning motion is basically like the inverse of an electric motor. It turns that motion into usable energy.

Answer 6

heat energy is used by steam turbines, diesel engines, petrol engines ... to rotate turbines or reciprocate engines ... which is mechanical energy
(eg. water is heated to form supersaturated steam, which explodes meaning volumetric expansion, when released inside turbine casing, causing it to rotate)

automobiles use them to power their forward/reverse motion

power plants use this mechanical energy to drive alternators which produce electricity by cutting across magnetic field produced by the rotating alternators.

in effect
heat energy > mechanical energy > magnetic energy > electric energy (electricity)

Answer 7

Easiest way is to conver to mechanical energy (steam) through a generator.