Optimization of solar thermoelectric systems operating under non-uniform irradiation

The concentrated solar thermoelectric generator (STEG) system is among the most promising technologies for converting solar energy into electricity. High-concentration focusing significantly enhances STEG system efficiency but also introduces challenges related to non-uniform solar irradiation, such as uneven temperature distribution and reduced performance. In this study, a theoretical model of the STEG system is developed to investigate the impact of thermoelectric leg distribution and structure on system performance under non-uniform irradiation. A novel heat collector design is proposed to alleviate the adverse effects of irradiation non-uniformity. The findings demonstrate that optimizing the leg structure, particularly through an X-shaped leg design, substantially improves system efficiency. At a system input power of 16.8 W, the maximum efficiency achieved with the X-shaped legs is 2.5 %, marking a 67 % improvement over conventional rectangular legs. Additionally, the newly designed heat collector ensures stable system output despite changes in irradiation uniformity. At an input power of 30 W, the temperature difference between the highest and lowest points on the hot side is reduced to just 22.2 K with the heat collector, compared to 87.1 K without it. This collector effectively mitigates the negative impacts of uneven irradiation, enhancing system uniformity and stability. These results provide valuable insights for the structural optimization of practical STEG systems.