Applications • Originally, the sterling engine was created to be a better alternative then the steam engines of the time and the application was one of a power source for factories of the time. Now, the use of the sterling engine has evolved past just the original use and the number of uses has increased. CHP - Combined Heat and Power Applications • CHP uses two sources of heat, a primary heat source and a secondary heat source where the temperature of the primary heat source is slightly higher than the secondary. Generally, such an engine is used in an agricultural or industrial application where a biomass can be used as the secondary source of fuel to create a near free fuel source. Heat Pumps • A heat pump essentially takes heat from the outside and pumps it into a cooler area. For a sterling engine, the components of the engine are reversed so the expansion side of the pump is places at a lower temperature then the compression side. In addition, because the pump is moving the heat in the opposite direction that it would naturally flow, the pump must do work on the gas in order for the pump to work. Sterling Cyrocoolers • A cyrocooler is the opposite of a heat pump where the sterling engine does work to reduce temperature. It works when the gas is compressed by the shaft the temperature of the gas increases, and the side of the piston is placed by a heat sink or a radiator of sorts to cool the gas and when the shaft decompresses the gas, the gas will be further cooled. The coldest side of the engine will be placed in an isolated environment like a refrigerator. Solar Power • It was stated that a sterling engine could use any external source of heat to run a sterling engine. Thus, the heat generated from the sun if a feasible source of heat. By placing the hot side of the sterling engine at the focus point of a parabolic mirror, the heat from the sun in focused on the piston that can generated enough heat to run the engine. Other Uses: There are many other uses for sterling engines that include uses in marine applications where noise is a concern, geothermal thermal application in which the heat from the earth is used and there is even a low temperature difference sterling engine that can use the heat of persons hands compared to room temperature to run the engine. However, low temperature difference engines do not generate much power and are generally used for demonstration.