The thermoacoustic refrigerator is a very unique type of heat engine that could potentially have a huge impact on how the everyday person keeps things cool. The basic principle behind this type of refrigerator is that sound waves can be used to transfer heat from one place to another. The idea that sound could be used to pump heat was first proposed by Lord Rayleigh in 1887 but was not fully researched until 1980 by a man named Rott. Only recently has the possibility of using thermoacoustic refrigerators commercially become achievable. The thermoacoustic heat engine basically consists of a resonator (speaker), heat exchangers, and a stack (or regenerator depending on the type).