Can Sound Waves Reduce Power Consumption?
By Michael Kanellos in Greentech Media, March 1 2010
It's an air conditioner, but it works sort of like a loudspeaker.
Palo Alto Research Center (PARC) has launched an effort to replace the mechanical compressors in refrigerators and air conditioners with thermoacoustic compressors. More details will come out at the ARPA-E Energy Innovation Summit taking place this week in Washington, D.C.
Thermoacoustic compressors essentially compress or expand gases with high-intensity sound waves. Compressing gases generates heat, while letting the gases expand cools things off. Think of the chill that gets created when a carbon dioxide cartridge is suddenly discharged and the gas is allowed to expand.
Mechanical compressors work on the same principle. Mechanical compressors, however, typically only achieve around 12 percent of the theoretical maximum. Thermoacoustic compressors can triple and more that efficiency rating because of the inherent properties of sound waves. A thermoacoustic compressor can potentially complete 10,000 cycles a second, according to Scott Elrod, vice president of the hardware systems laboratory and head of PARC's green tech efforts.
"You can do the same thing with a sound wave, but with more successive compression and expansion cycles," said Elrod. "It would look pretty much like a speaker but with high intensity sound waves."