Long-term energy management analysis of a novel solar thermoelectric generator based on photothermal conversion phase change materials in real-environment

Photothermal conversion phase change materials that integrate solar-thermal conversion with thermal management have emerged as a promising solution for energy management in solar thermoelectric generators. However, achieving long-term stable operation and significant advancements in light-thermal-electric conversion efficiency in real-environment is extremely challenging. In this study, the solar thermoelectric generators were designed utilizing novel photothermal conversion phase change materials with melting point of 60 °C and 90 °C respectively, and then the power generation performance of the generators were evaluated under varying actual solar irradiation conditions. The results showed that the designed system operated stably throughout the test, despite the fluctuating and unpredictable nature of actual solar irradiation. The stability can be attributed to the effective energy management mechanisms of the materials and the efficient heat transfer structure of the system. The maximum duration of the stable operation reached 12.93 h. Furthermore, the maximum open circuit voltage and the maximum output power were measured as 6.10 V and 10.63 W, respectively, under the summer climate conditions of the test site. Additionally, the maximum instantaneous light-electric conversion efficiency during the stable operation was recorded as 9.37 %. These breakthroughs will offer new insights for the mature application of solar thermoelectric generator.