Optimum design of thermoacoustic-piezoelectric systems with dynamic magnifiers

This study presents optimum design strategies for selecting the parameters of a class of energy harvesters, namely thermoacoustic-piezoelectric (TAP) systems, in order to improve various metrics that govern its performance. Augmenting a conventional TAP harvester with a properly designed elastic structure in order to amplify the strain experienced by the piezo-element is shown to significantly increase both its output power and efficiency. The proposed system is referred to as a dynamically magnified thermoacoustic- piezoelectric (DMTAP) harvester. The optimum design parameters of the DMTAP harvester are selected based on optimizing multi-objective criteria including power, efficiency and temperature difference. The resulting optimal performance metrics are computed and compared with those obtained by conventional means. Several configurations of the DMTAP harvesters are optimized and the obtained results indicate that these harvesters are capable of achieving around 1.6 times the maximum efficiency and requiring only about three-quarters of the temperature difference necessary to produce self-sustained oscillations in the harvester, compared with conventional TAP devices of the same size.