Peltier effect

Peltier effect It is the production or absorption of heat, caused by the passage of a current through the contact of two metals or one metal and a semiconductor

Summary

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  • 1 Historical background
  • 2 Principle of the Peltier effect
  • 3 Applications
  • 4 Sources

Historical background

The Peltier effect was discovered in 1834 by the French physicist Peltier JCA emerged on the basis of the discovery of the German physicist Seebeck TJ in 1821.

The essence of the Peltier effect, which is basically the opposite of the Seebeck effect, consists in passing a current from a continuous electrical energy source, through a circuit formed by two conductors of different nature, obtaining that one of its junctions absorbs heat and the other gives it up. The heat transferred by the hot focus will be the sum of the electrical energy supplied to the thermo element and the heat absorbed by the cold focus. These thermo elements, configured in this way, constitute a refrigeration machine.

Peltier effect principle

Principle of the Peltier effect

The body temperature corresponds to the average energy of its constituent particles. A body that loses particles with higher than average energy cools down. The electrons that cross a potential barrier are those with the highest energy: the metal that loses electrons in the semiconductor cools, the other one heats up.

It is necessary for the semiconductor to have a high thermoelectric power, a small electrical resistivity (that is, few Joule losses) and a weak thermal conductivity.

Applications

Peltier effect module

For applications, the metal-semiconductor contact is the most important (Bi2 Te3 bismuth tellurium)

Peltier effect modules are built containing up to several dozen pairs; They allow obtaining a temperature difference of 50 to 70 degrees Celsius between the two faces depending on the ambient temperature. These are polarized elements that must then be fed with direct current. (You can reverse the current to thaw the cold face)

In this way, laboratory cooling plates are built for analysis, reference of 0 degree centigrade for ice-water balance for calibration of thermoelectric pairs, etc. There are experimental refrigerators based on this principle, but their price is not yet competitive.

 

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