Thermoacoustic or acoustic refrigerators produce low temperatures using sound waves, so they won't harm Earth's protective ozone layer, which is damaged by freon and other refrigerant gases called CFC's, Symko said recently during the U.'s quarterly Science at Breakfast lecture at the Little America Hotel, Salt Lake City. So far, the tiny cooler has produced a temperature drop of 54 degrees Fahrenheit. Symko says he wants to improve the device so it can reduce temperatures by 90 to 180 degrees Fahrenheit. He hopes to patent the device this summer and make it available commercially in a few years. Conventional refrigerators use compressors to squeeze refrigerant gases and make them absorb heat.
Acoustic refrigerators use loudspeakers instead of compressors.
As sound waves travel through air or inert gases, some gas molecules are squeezed together and heat up while others expand and cool down. Plastic or cotton-wool plates sandwiched between heat exchangers get rid of heat to produce cooling. But most of the noise stays inside the device, so only a high-pitched whistle is heard outside. Commercial acoustic refrigerators will be insulated to keep them quiet. The Utah-built cooler is cheap.