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In the future, refrigerators and spacecraft electronics may be cooled by sound, thanks to research by University of Utah physicists.

Orest G. Symko, a U. physics professor who heads a team developing a palm-size "minifridge," said that within three or four seconds of when it's switched on, the experimental unit the group has made can cause a drop of 30 degrees Celsius (nearly 90 degrees Fahrenheit).The group hopes to get the temperature down 50 to 100 degrees Celsius, he said. That translates to 122 to 212 degrees F.

The device generates sound with a speaker the size of a half dollar. The 150 decibels are amplified to about 160, and the sound causes a change in temperature in the tiny device.

Since air is the medium, not the ozone-destroying chlorofluorocarbons that now waft through the coils of almost all coolers, the unit has potential for use in the home. CFCs will be eliminated from new refrigerators and air conditioners next year, and Symko said other chemicals that are to be substituted have problems, too.

But of the development, "We're talking about a very cheap refrigerator," Symko said. "This (showing the speaker) is the most expensive part - $4."

Even though the sound is of tremendous volume, he said, the units can be insulated for home use.

Symko discussed the team's work during a "Science at Breakfast" meeting of the U.'s College of Science, held Wednesday in the Little America Hotel.

Other than plates that vibrate inside the speaker, the refrigerator has no moving parts; it won't wear out easily, he said.

The project is funded by the Navy because small efficient units could be useful in cooling superconductor electronics that are used in satellites. Many military satellites that need super-cool equipment can make images of extremely fine details.

Asked about plans to develop the refrigerator commercially, Symko said, "We haven't discussed it. Our immediate goal is to get a drop of 50 to 100 degrees (Celsius)."

He also discussed work on a larger sound-powered refrigerator that is being developed by scientists working at the Los Alamos National Laboratory and the Naval Postgraduates School in Monterey, Calif. A 200-pound prototype of this type of refrigerator was tested aboard the space shuttle.

The smaller version built by the U. could be much better for satellites, because its mass is so much less.

Other members of the U. team include Thierry Klein and De Juan Zheng.