Thermoelectric performance and mechanical analysis of inner-arc type leg applied in solar thermoelectric generator

Abstract

The solar thermoelectric generator (STEG) is capable of converting solar energy directly into electricity. To solve the contradictory relationship between thermoelectric efficiency and thermal stress, a new type of internal-arc thermoelectric leg is proposed. A mathematical model of STEG is established, and the effects of leg structure on the thermoelectric performance and thermal stress of STEG are analyzed. The results show that the new thermoelectric leg has excellent power output, which is 10.82% higher than that of rectangular leg. At the same time, it has lower thermal stress, which is 3.82% lower than that of rectangular leg. As the indicator of STEG structure optimization, this study uses the critical power density that can reach 113.63 × 105W/m3 for the inner-arc type thermoelectric leg, which is 146.97% of the X-type leg. Taking into account the thermoelectric performance and thermal stress, the best configuration is X-type thermoelectric leg when the concentration ratio is between 0 ∼ 72.5, and the inner-arc type is preferred when the concentration ratio is between 72.5 ∼ 89.8. By conducting further optimization of the inner-arc type leg, it is possible to achieve an enhancement in the critical power density, amounting to a notable increase of 64.63%. These findings hold significant implications for guiding the structural design of STEG.