Editing Heat engine (section)

=== Everyday examples ===
Everyday examples of heat engines include the [[thermal power station]], [[internal combustion engine]], [[firearm]]s, [[refrigerator]]s and [[heat pump]]s. Power stations are examples of heat engines run in a forward direction in which heat flows from a hot reservoir and flows into a cool reservoir to produce work as the desired product. Refrigerators, [[air conditioner]]s and heat pumps are examples of heat engines that are run in reverse, i.e. they use work to take heat energy at a low temperature and raise its temperature in a more efficient way than the simple conversion of work into heat (either through friction or electrical resistance). Refrigerators remove heat from within a thermally sealed chamber at low temperature and vent waste heat at a higher temperature to the environment and heat pumps take heat from the low temperature environment and 'vent' it into a thermally sealed chamber (a house) at higher temperature.

In general heat engines exploit the thermal properties associated with the expansion and compression of gases according to the [[gas laws]] or the properties associated with [[phase transition|phase changes]] between gas and liquid states.