RESEARCHERS have been trying to evolvea refrigerator that would cut down onpower consumption and at the sametime prevent the depletion of earth'sozone layer. Now, scientists from theRussian Institute of Light Alloys (VILS)in Moscow have successfully testeda new refrigerating unit that neither usesan electric motor nor a compressor, andhence consumes a lot less electricity.One of the major factors that contributes to ozone depletion is freon,a widely used refrigerant. The new unitdoes not use freon and other traditionalcoolants.
The scientists have put ke well-known Peltier effect to good, practicableuse. According to Peltier, when anelectric current flows through a semi-conducting system, heat appears on oneof the crystal plates and the other plateis cooled. The effect has been usedin military equipment and in cosmonautics (cooling laser guidancesystems).
A Kichkailo and V Pletanov fromESMAN, an Ukrainian industrial researchinstitute, developed the new refrigerator using semiconductors madeof tellurobismuth alloys. The alloyhas properties of a crystal. The crystalis cut into small rectangular pieces andabout 100 such pieces are united ina module. They are oriented in sucha way that half of them release cold intoa plate and the rest evolve heat. The heatis removed from the second plate by apipe as in traditional refrigerators or isblown away by a blower.Semiconductor elements have a verylong life and the only part to beexchanged periodically is the worn-outheat pipe - a minor repair.
VILS started off with a five litre thermostat and the interiors cooled to -1 Ycvery rapidly. Then it made two experimental refrigerators of the conventional165-litre capacity without compressors- one with a heating pipe and the otherwith a blower. The models were tested atthe Smolensk refrigerating machineplant in Russia and after minor adjustments, both the models achieved cooling to -25' c in an ambient temperatureof more than 30'c. The Smolensk plantis planning to test run six other modelsand will finance commercial productionof such refrigerators shortly.