What are the possible applications for thermoacoustic technology? Are they useful at all temperatures?
At this point, we do not see any cooling application that is not suited to thermoacoustics. Conventional, single-stage, electrically operated thermoacoustic refrigerators can reach cold-side temperatures which are two-thirds to three-quarters of ambient, so they are not well-suited to cryogenic applications (T < -40 C = -40 F). Thermoacoustically driven pulse-tube style refrigerators have been built at Los Alamos National Labs, CFIC, Inc. (Troy, NY) and Praxair (Tonawanda, NY) that can reach the cryogenic temperatures required to liquefy air or natural gas. In its early commercial stages, thermoacoustic refrigerators will probably be limited to niche applications such as in military systems which are required to operate in closed environments and food merchandising where toxicity is an important issue. As global environmental legislation, such as the Montreal Protocols on Substances which Deplete Stratospheric Ozone and the Kyoto Accord become more restrictive, we expect the scope of t
