Influence of DC flow on the performance of a bypass-typed heat-driven thermoacoustic refrigerator

Looped heat-driven thermoacoustic refrigeration (HDTR) is a reliable and environmentally-friendly cooling technology, while its performance is significantly influenced by DC flow. This work numerically investigates the influence of DC flow on the performance of a novel, highly efficient looped HDTR with bypass tube. The system exhibits a much higher coefficient of performance (COP) than traditional HDTRs when DC flow is completely suppressed. The effect of DC flow on key parameter distributions is first explored, revealing that DC flow causes deviation from linearity in axial temperature distribution of regenerator in engine. Subsequently, the influence of DC flow on the system performance is investigated in detail. The results indicate that a positive (i.e., anticlockwise) DC flow increases cooling power, while a negative (i.e., clockwise) DC flow results in a remarkable decline. However, the presence of DC flow reduces COP, regardless of direction. The cooling power enlarges from 4.4 kW to 11.7 kW while COP drops from 1.79 to 1.30 as dimensionless DC flow increases from 0 to 0.5 %; nevertheless, they both near zero with a negative value of-1.0 %. Moreover, the method to suppress DC flow is discussed, and the elastic membrane is selected in subsequent experiments due to simplicity and complete suppression.