Experimental study on the thermoelectric performance of a thermoelectric generator coupled with phase change thermal storage under periodic transient heat sources

Thermoelectric generators (TEGs) can directly convert thermal energy into electrical energy, exhibiting great application potential. Integrating phase change materials (PCMs) with TEGs can alleviate the performance instability of TEGs caused by heat source fluctuations. In this study, a PCM-TEG experimental system was built, and its thermoelectric performance was investigated under periodic transient heat sources. Under the experimental conditions of 100 W heating power and a 100 min cycle period, the PCM-integrated system reduces the output power fluctuation by 53.0% compared with the TEG system without PCM, although accompanied by a 34.4% reduction in the average output power. As the cycle period increases, the system output power gradually rises, and the average efficiency reaches 1.50% at a cycle period of 140 min. However, the voltage fluctuation amplitude increases with the cycle period, which is unfavorable to the stable operation of TEGs. A higher heating power leads to more heat storage in the heating zone and significantly enhances power generation performance. When the heating power increases from 60 W to 120 W, the average output power and maximum average efficiency are improved by 249.3% and 71.9%, respectively. The heating power is identified as a key factor governing the full utilization of the thermal storage capacity of PCMs in the system. The results of this work can provide guidance for the design and operation of PCM-integrated systems.