A heat-driven thermoacoustic refrigerator/heat pump for solar-thermal application: Building cooling and heating solution with low-cost potential and high performance

Despite the eco-friendly working substance, exceptional reliability and long lifespan, the advancement of heat-driven thermoacoustic refrigerators/heat pumps (HDTRs/HDTHPs) is impeded by challenges related to high costs and low efficiency. For the thermal utilization in the temperature range of parabolic trough and linear Fresnel solar collectors, this study proposes an HDTR/HDTHP utilizing nitrogen as the working gas and incorporating a gas-liquid resonator to achieve building cooling and heating with low-cost potential and high performance. Firstly, simulations are performed and reveal that the refrigerator/heat pump exhibits a traveling-wave-dominated acoustic field distribution, which is crucial for efficiency enhancement. Subsequently, experiments are conducted to investigate its performance in two operating modes. In heating-only mode with the heating, heat-pumping, and ambient temperatures maintained at 300 °C, 50 °C, and 10 °C, the refrigerator/heat pump exhibits a heating power of 7.31 kW and a coefficient of performance of heating (COPh) of 1.28. In cooling-only mode, at the heating, ambient, and cooling temperatures of 300 °C, 35 °C, and 7 °C, the refrigerator/heat pump achieves a coefficient of performance of cooling (COPc) of 0.34 and a cooling power of 2.75 kW. Comparative analysis indicates that this refrigerator/heat pump may offer a viable approach for realizing low-cost and high-performance solar cooling and heating in buildings.