Development of a sunlight-driven thermoacoustic engine for solar energy harvesting

Solar-powered thermoacoustic engine (TAE) is a promising technology for harvesting solar energy. In this study, a prototype of triple quarter-wavelength standing-wave TAEs with different total lengths (0.195 m, 0.235 m, and 0.275 m) driven by sunlight collected by three Fresnel lenses (diameter 0.36 m) is constructed and tested. Experimental results show that when the ceramic honeycomb is heated by the sunlight, the triple TAEs resonate at steady state at the fundamental frequencies of 312 Hz, 366 Hz and 435 Hz, respectively. These values are in reasonable agreement with those predicted by the reduced-order network model. For the TAE operating at 366 Hz, acoustic oscillations with a sound pressure level of 140 dB are measured at the TAE outlet, and the acoustic power generation in the ceramic honeycomb is estimated to be 0.135 W. The potential applications of the proposed sunlight-driven TAEs are then envisaged. This work demonstrates the feasibility of converting solar energy into acoustic power using thermoacoustic technology, providing great guidance for prospective studies on the development of solar-driven thermoacoustic electric generators and refrigerators.