Power generation through Thermoelectric generators

What are Thermoelectric generators?

Thermoelectric generators are devices which convert heat directly into electrical energy, using a phenomenon called the Thermoelectric effect(Seebeck effect).

                          

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TEG uses a phenomenon called Seebeck effect. Seebeck is the conversion of temperature differences directly into electricity. Seebeck discovered that a compass needle would be deflected when a closed loop was formed of two metals joined in two places with a temperature difference between the junctions. This is because the metals respond differently to the temperature difference, which creates a current loop, which produces a magnetic field. Seebeck, however, at this time did not recognize there was an electric current involved, so he called the phenomenon the thermomagnetic effect, thinking that the two metals became magnetically polarized by the temperature gradient. The Danish physicist Hans Christian played a vital role in explaining and conceiving the term “thermoelectricity”.

 When heat and cold are applied, the device then generates electricity.

Generation of electricity from Thermoelectric generators

Fig. shows how exactly TEG works. When heat is applied at the heat end side and the coolant side is kept in free space, heat flows from heat end to coolant end , thus moving holes from p-type and electrons from n-type  collected at two wires.

Their construction consists of pairs of p-type and n-type semiconductor materials forming a thermocouple. These thermocouples are then connected electrically forming an array of multiple thermocouples (thermopile). They are then sandwiched between two thin ceramic wafers.

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