Thermoelectric Refrigerator

Peltier effect has been used to develop thermo-electric refrigerator. According to this effect we know that heat is absorbed at one end and liberated at the other junctions of the thermo couple when a current is passed into a thermocouple having its two junctions at different temperatures. If on the whole heat is removed, such a thermo couple would work as a refrigerator.

Thermo-electric power of germanium at room temperature is about 1 millivolt/degree. Also its thermal conductivity is very much lower than that of metals. Hence a semiconductor can be used an effective refrigerator using the Peltier effect.

On the principle a refrigerator 1cu. Ft cold box has been designed. It consists of 182 thermocouples and reduces the temperature of air by 20-30o C. It takes about 5-10 amperes from a battery or mains.