Performance analysis of the standing wave thermoacoustic refrigerator: A review

Concerns over environmental impacts of hazardous refrigerants have spurred much research into alternative technologies as well as more environmentally friendly refrigerants. A thermoacoustic refrigeration system uses no refrigerant but is currently not a feasible solution due to the still immature technology with much still unknown about the theories that explain the thermoacoustc cooling effects and the desired performance. This paper reviews past studies to achieve the desired outputs; lowest temperature, the highest temperature difference generated across the stack, the lowest acoustical work required for cooling, or/and the highest coefficient of performance (COP) of the standing wave thermoacoustic refrigerator and various attempts at optimization in terms of the many parameters that represent the outcomes. The review looked at methods employed to analyze the performance with discussions on the relevant parameters that must and have been be considered by past researchers. To date, most studies have been focused on the stack, the heart of the system. Optimization work has been performed parametrically, experimentally or/and numerically, where discrete variations of the parameters investigated are completed whilst others are held constant. Lately, genetic algorithm, a statistical approach, has been utilized in simultaneous optimization of the parameters of the desired outputs where conflicting objectives are possible. To date, thermoacoustic refrigerator remains an attractive alternative technology towards a global agenda of a more sustainable future.