A high-efficiency gas-liquid coupled heat-driven thermoacoustic heat pump

The search for a diversified and sustainable technology for energy utilisation is crucial for reducing the consumption of fossil energy. This research proposed a novel heat-driven thermoacoustic heat pump with a gas-liquid coupled resonator that exhibits high efficiency, compact structure and easy fabrication. A series of theoretical and experimental studies has been performed in this work, including numerical and experimental domestic heating performance, onset characteristics as well as the effects of different liquid masses and high and ambient temperatures on the performance of a heat pump. Results show that the theoretical and experimental heat pump performance exhibit good agreement, with a standard error of about 5%. Moreover, the gas-liquid coupled heat-driven thermoacoustic heat pump has a low onset temperature (70 degrees C at 3 MPa), offering a wide range of applications for low-grade thermal energy utilisation. With high, ambient and domestic heating temperatures of 300 degrees C, 10 degrees C and 50 degrees C, respectively, a maximum domestic heating power of 18.4 kW is obtained, corresponding to the maximum coefficient of performance of domestic heating based on heating power (COPh) of 1.48. Furthermore, a maximum relative Carnot efficiency of 50.9% and a COPh of 1.31 with a hot-end temperature of 300 degrees C are achieved under ambient and domestic heating temperatures of -20 degrees C and 50 degrees C, respectively. These results present a new domestic heating approach for the utilisation of medium- and low-grade thermal energy.