Numerical Simulation of Thermoelectric Modules with Hollow-Filled Structure

With the emphasis on sustainable development and increased fossil fuel pollution, thermoelectric generators (TEGs) are gradually being applied to industrial waste heat and geothermal energy. However, their utilization efficiency is still low and the cost is high. Thus, improving output power has been one of the essential issues in the research of thermoelectric modules. Based on a TEG with only one pair of p - and n -legs (1-PN-TEG), 1-PN-TEG with a hollow structure (HTEM) and 1-PN-TEG with a hollow-filled structure (HFTEM) are proposed in this paper. The HTEM and HFTEM were numerically simulated by COMSOL. The parameters were evaluated in comparison with a traditional thermoelectric model (TTEM) and a previously reported multilayer composite structured thermoelectric module (MCTEM). Compared with the TTEM, the HTEM has more significant internal resistance and lower current and output power. However, when the volume of the hollow section reaches a specific value, the power per unit volume of the HTEM will exceed that of the TTEM. The output power and power per volume of the HFTEM are more remarkable than those of the TTEM. At a temperature difference of 35°C, the power of the HFTEM is 2.4 times that of the TTEM, and the power per unit volume is three times that of the TTEM. These results show that thermoelectric modules with a hollow-filled structure can improve the performance of TEGs and reduce the volume of semiconductor materials used, which has broad application prospects.