Energy harvesting of thermoacoustic-piezo systems with a dynamic magnifier

This study presents a novel approach for enhancing the performance of one of the promising systems in the field of energy harvesting, namely the standing wave thermoacoustic engine. Currently, conventional thermoacoustic engines have been integrated with piezoelectric membranes to harness the acoustic energy associated with this class of engines. In these thermoacoustic-piezoelectric (TAP) harvesters, the acoustic to electric energy conversion efficiency vary typically from 10% to 15%. In this paper, an attempt is made to magnify the electric energy harnessed from the piezo membranes by providing the harvester with a dynamic magnifier. The proposed system will be referred to as a dynamically magnified thermoacoustic-piezo system (DMTAP). The main purpose of the dynamic magnifier, as implied by the name, is to magnify the strain experienced by the piezo-element. With proper selection of the design parameters of such a magnifier, the output power can be significantly increased. The theory as well as the equations governing the operation of the system before and after the addition of the dynamic magnification is presented. Numerical examples are provided to illustrate the performance characteristics and merits of the improved (DMTAP) system as compared with those of a conventional TAP.