Modelling and analysis of a thermoacoustic-piezoelectric energy harvester

Abstract

This paper proposes an energy harvester that can convert the acoustic power produced by a standing-wave thermoacoustic engine into electricity using a piezoelectric transducer. The proposed thermoacoustic-piezoelectric system may start producing electricity when sufficient heat input is supplied and large-amplitude thermoacoustic oscillations are generated. The stability of the thermoacoustic-piezoelectric energy harvester is analysed using a transfer matrix method based on linear thermoacoustic theory. Experimental results are presented to validate the predicted onset temperature difference across the stack and oscillation frequency. Subsequently, the acoustic field, viscous and thermal losses and acoustic power generation along the tube at the threshold condition are analysed. The present work also focuses on the effect of the temperature distribution of the system on the onset characteristics and the energy conversion process. In addition, a parametric study is performed to investigate the effect of the main geometrical and electrical parameters on the onset characteristics of the entire system. The analytical and experimental approaches developed in this study are useful for the design and optimization of thermoacoustic-piezoelectric engines for harvesting waste thermal energy in industrial applications.