Thermoelectric energy conversion

If an electric current were to be passed through the device from an outside source, heat would be absorbed at one junction and released at the other. The device then operates as a soHd-state heat pump. 

In thermoelectric cooling appHcations, extensive use has been made of cascaded systems to attain very low temperatures, but because the final stage is so small compared to the others, the thermal flux is limited (Eig. 3). The relative sizes of the stages ate adjusted to obtain the maximum AT. Thus, for higher cooling capacity, the size of each stage is increased while the area ratios ate maintained. 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

The basic ideas of thermoelectricity have been known for nearly two centuries, but until well after the Second World War the primary use was for temperature measurement (qv) using metallic wires. Then, upon improvements in semiconductor technology, thermoelectric power generation and refrigeration came under serious consideration. 

In 1857, Thomson (Lord Kelvin) placed the whole field on firmer footing by using the newly developing field of thermodynamics (qv) to clarify the relationship between the Seebeck and the Peltier effects. He also discovered what is subsequently known as the Thomson effect, a much weaker thermoelectric phenomenon that causes the generation or absorption of heat, other than Joule heat, along a current-carrying conductor in a temperature gradient. 

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