Effect of Stack Spacing on the Performance of Thermoacoustic Refrigerators Using Helium and Air as Working Substances

摘要

This paper deals with the design of thermoacoustic refrigerators using linear thermoacoustic theory. The refrigerator components are designed at 3% drive ratio by considering the practical limitations of providing sufficient spacing for attaching the loudspeaker to the resonator tube and accommodating instrumentation. The effects of spiral stack spacing in terms of thermal penetration depth on the theoretical performance of refrigerator using helium and air as working substances are discussed. The quarter-wavelength resonator designs with taper and divergent section terminated with hemispherical end are optimized with helium and air for better performance. Theoretical results are validated with DeltaEC software results and are in agreement with each other. Helium shows better performance compared to air but lacks power density. The DeltaEC predicts COP 0.514 at the cold heat exchanger temperature of -30℃ with helium compared to air (COP 0.616 at 8.8℃) for the 50 W cooling power 100 mm diameter quarter-wavelength resonator designs.