Briefs: Thermoacoustics for air conditioning

The Palo Alto Research Center (PARC), is developing a new form of refrigeration for cooling at room temperature, based on thermoacoustics, which was previously used only for cryogenic temperatures. The technology PARC developed is claimed to double the efficiency of the best current residential and commercial air-conditioning and refrigeration systems. The principle uses the temperature oscillations present in sound waves. In this case, gases are inserted into a tube filled with mesh membranes called regenerators. A sound wave passing through the device causes a low-pressure/low-temperature/high-pressure/high-temperature gradient to form. Heat exchangers at each end recover the thermal energy which can then be exploited. This novel acoustic power-recovery technique is claimed to achieve a COP of 9, i.e. more than double that of the best current compression systems. PARC intends to present a full-scale demonstration unit within a year. According to PARC, this technology could reduce power consumption required for cooling in the USA by 13%.