Design and experimental evaluation of a travelling wave thermoacoustic cooler driven by a standing wave thermoacoustic engine

This paper presents the design and experimental results obtained for a coaxial travelling wave thermoacoustic cooler driven by a standing wave thermoacoustic engine. The system is developed to be low-cost, for a target user base in remote rural areas of developing countries. Biomass combustion can be used to power the engine and produce refrigeration effect at the cooler. The coupling configuration of a standing wave engine and coaxial travelling wave cooler is chosen due to its comparatively low cost and compact design. The design procedure performed here is based on linear thermoacoustic theory. Due to reasonably efficient energy conversion at low cost, compressed air at 10 bar pressure is employed as a working fluid. The operating frequency of the device is 46 Hz. Two-microphone method is used to validate the acoustic power created by the standing wave engine that powers the travelling wave cooler. The performance of the system is measured at different input powers to the standing wave engine. So far, the lowest temperature achieved without any cooling load was -5°C.