Analysis and experimentation of a single stage travelling-wave thermoacoustic engine

Abstract

Clean and sustainable energy has become the most significant necessity in the modern world due to the growth of the population and the scarcity of conventional energy sources. Moreover, using fossil fuels hurts the environment, biodiversity, and the health and well-being of both present and future generations. Currently, 30–50% of waste heat is produced by fossil fuels, and the emission of greenhouse gases and fuel consumption can be mitigated by recovering waste heat by using heat recovery techniques such as organic Rankine cycles, regenerators, and plate heat exchangers. Thermoacoustic technology harnesses the waste heat from low-grade waste heat sources by converting it into acoustic energy and then into electricity. Still, it remains a relatively nascent field, and ongoing research is being done to develop conversion efficiency. The impact of the design parameters of the device on conversion efficiency was studied. According to the study, the working fluid temperature and the stack length are crucial to energy conversion efficiency. Based on the results, as the working fluid temperature increases, there is a noticeable rise in both pressure amplitude and volume flowrate amplitude, along with an improvement in efficiency, all while maintaining a constant regenerator length. Similarly, efficiency increases with longer regenerator lengths when the working fluid temperature is held constant. If the working fluid temperature increases by 1 degree Celsius while maintaining the regenerator length constant, the pressure amplitude is increased by 6.2%. Higher efficiencies can be achieved by increasing the stack length, yet an upper limit exists. The efficiency is limited after a certain regenerator length because the expected acoustic behavior vanishes. These findings suggest the importance of both working fluid temperature and regenerator length in optimizing the efficiency of thermoacoustic energy conversion systems