actually this post related with my final project to finished my bachelor degree in mechanical engineering. so, what i’m going to tell you is : multi stages thermolectric (peltier element)
Early 19th century scientists, Thomas Seebeck and Jean Peltier, first discovered the phenomena that are the basisfor today’s thermoelectric industry. Seebeck found that if you placed a temperature gradient across the junctionsof two dissimilar conductors, electrical current would flow. Peltier, on the other hand, learned that passingcurrent through two dissimilar electrical conductors, caused heat to be either emitted or absorbed at the junctionof the materials. It was only after mid-20th Century advancements in semiconductor technology, however, thatpractical applications for thermoelectric devices became feasible. With modern techniques, we can now producethermoelectric “modules” that deliver efficient solid state heat-pumping for both cooling and heating; many ofthese units can also be used to generate DC power in special circumstances (e.g., conversion of waste heat).New and often elegant uses for thermoelectrics continue to be developed each day.
as you can see in the picture, thermoelctric consist of couples semi conductor (Type P & Type N) electron will move from the higher energy element (type n) to the lower one. each side of the thermoelectric will be covered by ceramics, when the electric current flows to the thermoelectric, temperature different between each side will occur, that’s why we can use this device as a heat pump without moving part.