Realizing ultrahigh ZT value and efficiency of the Bi2Te3 thermoelectric module by periodic heating

Abstract

Thermoelectric power generation is regarded as a promising technology to convert waste heat into electricity. This study aims to address the low conversion efficiency of thermoelectric modules and introduces a novel periodic heating method to enhance their performance. Two new indicators, time average ZTta value and effective conversion efficiency, are introduced to assess the dynamic behavior of thermoelectric modules. A Bi2Te3-based thermoelectric module with n-type Bi2Te3-xSex and p-type BixSb2-xTe3 materials is adopted as the research objective and tested on a designed transient experimental setup. Besides, a transient numerical model is developed to explore the optimal transient heat source and study the effect of various parameters on dynamic behavior. Compared with the steady-state efficiency of 3.76% and ZTta value of 0.78 at a heat supply of 60 W, the time average efficiency and ZTta value are improved by 52.93% and 43.59% respectively using the periodic heating method. Also, a smaller leg height, a larger leg area, more TE couples, and lower thermal conductivity are suggested for improving the dynamic behavior. This work offers a new periodic heating method to improve the output performance of thermoelectric modules, which may promote the broader application of thermoelectric power generation technology.