Thermoacoutsitc Stirling Engine
Thermoacoustic devices are very different from Stirling devices, although the individual path traveled by each working gas molecule does follow a real Stirling cycle. These devices include the thermoacoustic engine and thermoacoustic refrigerator(cold side). High-amplitude acoustic standing waves cause compression and expansion analogous to a Stirling power piston, while out-of-phase acoustic traveling waves cause displacement along a temperature gradient, analogous to a Stirling displacer piston. Thus a Thermoacoustic device typically does not have a displacer, as found in a beta or gamma Stirling.