Acoustic field and power matching mechanism in looped heat-driven thermoacoustic refrigerators

Abstract

Heat-driven thermoacoustic refrigerators (HDTRs) offer great potential for the sustainable energy development due to their environmental friendliness, high reliability, and promising efficiency. However, there remains a gap in the comprehensive study and understanding of their acoustic matching and energy conversion mechanisms, the resolution of which would facilitate the development of more efficient HDTRs. This work employs Sage to model fundamental thermoacoustic engines and coolers, aiming to explore the effects of temperature and acoustic fields on their performance. It highlights the acoustic and temperature-matching patterns of looped HDTRs operating at room temperature range. The optimal impedance phase for the thermoacoustic engine and cooler is located on the negative and positive sides, respectively, of the pure traveling wave zero-phase point. The thermal buffer tube provides better phase matching between the engine outlet and cooler inlet compared to the resonator tube. Focusing on a single-unit HDTR system, the present study evaluates the steady-state performance and acoustic distribution analysis for systems different connections and couplings. Additionally, it compares looped HDTRs with various coupling configurations from the literature, further confirming the superior refrigeration performance of directly coupled systems. These findings provide valuable insights for developing more efficient thermoacoustic refrigerators, contributing to sustainable energy advancement.