Study of a gas-liquid-coupled heat-driven room-temperature thermoacoustic refrigerator with different working gases

Abstract In a thermoacoustic system, the working gas is the carrier for the conversion between thermal energy and acoustic power. It is therefore important to explore the influence of different working gases on the performance of a thermoacoustic refrigerator. A new type of gas–liquid coupled thermoacoustic refrigerator has a lower onset temperature and higher energy-conversion efficiency than traditional thermoacoustic refrigerators, which is of great promise in low-grade heat recovery and motivates further development. This paper studies a gas–liquid-coupled heat-driven thermoacoustic refrigerator with different working gases, i.e., hydrogen, helium, nitrogen and argon, under onset and steady operations. First, transfer matrix method based on thermoacoustic theory is used to study the onset characteristics of the system. Analysis is then performed on the axial distributions of key parameters including acoustic power and total power. Finally, under different mean pressures and heating temperatures, system cooling performance is analyzed for different working gases. The results show that coefficient of performance (COP) of the system decreases with increasing pressure. The COPs of the system using hydrogen and helium are less affected by pressure, which remain in the range of 0.60 to 0.72. With heating temperature of 400 K and cooling temperature of 270 K, in the most efficient condition, the system can achieve a COP of 0.71 and a cooling power of 468 W using 1 MPa hydrogen; in the largest cooling capacity condition, the system can achieve a cooling power of 4557 W and a COP of 0.65 using 10 MPa hydrogen. This research can provide guidance for designing heat-driven thermoacoustic refrigerators under different working gases.