Goodbye, freon
RESEARCHERS have been trying to evolve a refrigerator that would cut down on power consumption and at the same time prevent the depletion of earth's ozone layer. Now, scientists from the Russian Institute of Light Alloys (VILS) in Moscow have successfully tested a new refrigerating unit that neither uses an electric motor nor a compressor, and hence consumes a lot less electricity. One of the major factors that contributes to ozone depletion is freon, a widely used refrigerant. The new unit does not use freon and other traditional coolants.
The scientists have put ke well-known Peltier effect to good, practicable use. According to Peltier, when an electric current flows through a semi- conducting system, heat appears on one of the crystal plates and the other plate is cooled. The effect has been used in military equipment and in cosmonautics (cooling laser guidance systems).
A Kichkailo and V Pletanov from ESMAN, an Ukrainian industrial research institute, developed the new refrigerator using semiconductors made of tellurobismuth alloys. The alloy has properties of a crystal. The crystal is cut into small rectangular pieces and about 100 such pieces are united in a module. They are oriented in such a way that half of them release cold into a plate and the rest evolve heat. The heat is removed from the second plate by a pipe as in traditional refrigerators or is blown away by a blower. Semiconductor elements have a very long life and the only part to be exchanged periodically is the worn-out heat pipe - a minor repair.
VILS started off with a five litre thermostat and the interiors cooled to -1 Yc very rapidly. Then it made two experimental refrigerators of the conventional 165-litre capacity without compressors - one with a heating pipe and the other with a blower. The models were tested at the Smolensk refrigerating machine plant in Russia and after minor adjustments, both the models achieved cooling to -25' c in an ambient temperature of more than 30'c. The Smolensk plant is planning to test run six other models and will finance commercial production of such refrigerators shortly.