Thermoelectric refrigerators SHIVAKI based on Peltier principle
Operation principle of thermoelectric refrigerator SHIVAKI
Operation of thermoelectric refrigerator SHIVAKI is based on two effects originating in Peltier unit:
1) thermal-to-electricity conversion effect in conductors;
2) direct heating and cooling effect on junctions of two cionductors by means of passing current.
Thermoelectric refrigerators SHIVAKI have a number of specific advantages which make them unique and having no competitors in some fields of human activitiy. In particular, such advantages include extremely compact dimensions of thermocouples, their high reliability due to simple design, and the ability to keep good performance in conditions of significant acclelerations/overloads. Unlike the compression and absorption refrigerator units, thermocouples with simplified design can maintain their operational capability when turned over or in weightlessness conditions.
Despite it's compressionless technology, thermoelectric refrigerator SHIVAKI has high cooling performance thanks to it's dual refrigeration system. Dual refrigeration system– allows to control the set temperature stability within a wide range of external temperatures. Low noise level, no need for periodic defrosting, plus small size and weight - make the thermoelectric refrigerator SHIVAKI more attractive than other refrigerators in the same class but with different type of refrigeration system.
Sketch of Peltier elements
1) Cold contact bridge,
2) Hot contact bridge,
3 + 4) Longitudinal element made of alloyed semiconductor material.
To achieve the required refrigeration power, it's necessary to connect several elements into one Peltier refrigeration unit. Peltier effect is one of the three thermoelectric effects describing how to get temperature difference by means of electric current. This effect occurs when two various metals (or semiconductors) are connected with each other in two places, and electric current goes through them.
Electric current initiates heat transfer from one junction place to the other dependent on current strength and direction. This effect has found it's engineering application in Peltier refrigeration units.
Jean Peltier published his discovery in 1834. Intense investigations of materials with good thermoelectric properties were conducted in 60-s and 70-s. In particular, the restriction of coolants containing chlorofluorocarbon (CFCs) gave rise to this development, because this type of cooling system didn't use any fluids, gases, but only semiconductors.