Numerical and experimental investigation on a novel heat-driven thermoacoustic refrigerator for room-temperature cooling

Abstract

• A two-unit medium- and low-grade thermal energy driven thermoacoustic refrigerator was tested. • Direct-connection between engine and cooler cores was applied to improve cooling performance. • Cooling power of 5.62 kW with COP of 0.41 at heating, cooling and ambient temperatures of 300 ℃, 10 ℃ and 45 ℃ was obtained. • System can work with cooling temperature range from -30 ℃ to 10 ℃ with ambient temperature up to 50 ℃. We report a two-unit thermoacoustic refrigerator driven by medium- and low-grade thermal energy for the room-temperature cooling. Carefully designed slim tubes and cavities were adopted as an efficient resonance component to further increase the power density of system. Systematic experiments, including onset characteristics, refrigeration performances, and impacts of DC (direct-current) and jet flow were tested for a comprehensive understanding of the working mechanism of the system. Experimental results show that a minimum onset temperature of 64 ℃ could be obtained, revealing a wide application foreground for low-grade thermal energy recovery. Additionally, a cooling power ranging from 0.66 kW to 5.62 kW, with the corresponding coefficient of performance from 0.12 to 0.41 and the cooling temperature from -30 ℃ to 10 ℃, was achieved. Importantly, a power density as high as kW/m 3 was obtained. To the authors’ knowledge, this is the highest ever power density achieved in heat-driven’ thermoacoustic refrigerators for room-temperature cooling, with similar heating temperatures. This demonstrates attractive application for heat-driven room-temperature cooling.