The impact of gas blockage on the performance of a thermoacoustic refrigerator

Abstract

Thermoacoustics deals with the conversion of sound energy into heat and vice versa. Thermoacoustic refrigerator is a device that transfers heat from a cold medium to warm medium by using sound energy as a work input. In this paper, the impact of the gas blockage was investigated for three cases; no heat exchanger, heat exchanger with small thermal contact area and heat exchanger with large thermal contact area. The experiments were conducted in a half-wavelength standing wave resonator. The position of the stack was optimized experimentally and was in good agreement with the theoretical value. The results show that the gas blockage has a significant impact on the thermoacoustic process inside the stack. The temperature difference across the stack decreases with an increase in the gas blockage. The relationship between the gas blockage fraction and the temperature difference across the stack is linear. The impact of heat exchangers on the thermoacoustic process was also studied. The results show that a heat exchanger with larger thermal contact area increases the heat exchange between the heat exchanger fluid and the stack, but reduces the cooling power and increases the work input to the stack due to the increased gas blockage. It is concluded that when thermoacoustic devices are used as a refrigerator, there is a compromise between the cooling power of the device and the heat exchanged with the heat exchangers. Therefore, the optimization of these parameters is necessary in order to optimize the performance of the thermoacoustic refrigerator.