The effect of mean pressure on the performance of a single-stage heat-driven thermoacoustic cooler

Waste heat is a global environmental issue. There are some technologies that can be used to recovery waste heat, one of which is thermoacoustic technology. Thermoacoustic technology can be divided into two parts; one is the thermoacoustic engine, and the other is the thermoacoustic heat pump. Using the combination of engine and heat pump, we can build a heat-driven thermoacoustic cooler. When an acoustic wave propagates in a narrow tube, a gas in the tube makes thermal interactions with the tube wall. As a result of these thermal interactions, an energy conversion between acoustical and thermal power take place. Then, the thermoacoustic engine which produces acoustical power drives the thermoacoustic heat pump to pump heat from the cold side to the ambient side. The cooler system consists of a looped tube, an engine regenerator and a heat pump regenerator. The acoustic wave spontaneously generates as the engine regenerator is heated. Afterwards, due to the energy conversion, acoustic power is generated. The acoustic wave travels along the looped tube then the acoustic power carried by the acoustic wave is consumed by the heat pump regenerator. There are some parameters that have impact on the performance of the thermoacoustic cooler system, one of which is the mean pressure. To design a cooler system having high efficiency and lower onset heating temperature, the effect of mean pressure is investigated. By increasing mean pressure, the onset heating temperature generating acoustic power can be decreased from 558°C to 307°C. Moreover, the efficiency of the engine regenerator reaches 73% of Carnot’s efficiency, Efficiency of the cooler regenerator attain 43% of the upper limit values and 49% of the acoustical work generated by the engine regenerator as utilised in the cooler regenerator. As a result, 15% of the thermodynamic upper limit value of the whole cooler system is achieved.