What are the other alternative refrigeration techniques that are as environmentally benign as thermoacoustics?
Prior to the commercial introduction of CFCs for refrigeration and air conditioning in the 1940’s, ammonia was used as a working fluid for vapor compression refrigeration in homes. It was abandoned due to its toxicity, but is still in widespread use for industrial and agricultural applications. In Europe, and particularly in Germany, hydrocarbons, such as propane and butane, are used in small quantities for domestic refrigerators. Due to their flammability and explosive potential, they may not be suitable for applications requiring larger cooling capacities, such as air conditioners. (The hydrocarbon issues are related to safety, not global warming). Stirling cycle refrigerators also work best with inert gases and have efficiencies that are equal to thermoacoustic machines. The drawback of typical Stirling machines is that they are far more complicated and therefore much more expensive to produce and maintain. It is also possible to produce refrigerators that are based on solid-state t
