Optimal design of a novel thermoelectric generator with linear-shaped structure under different operating temperature conditions

A novel linear-shaped thermoelectric generator (Liner-TEG), due to its unique structure in which the p- and n-type thermoelements can be optimized independently, usually exhibits better design flexibility than a traditional π-shaped thermoelectric generator (π-TEG). In this study, the influence of the length ratio of the thermoelements θ = Lp/(Lp + Ln) on the output power and conversion efficiency of Linear-TEGs is investigated for different total lengths and heights of the thermoelements. And the predictive models on the thermoelectric performance under two operating temperature conditions are built, individually. The results show that, the maximum power and maximum efficiency are obtained at different length ratios; none of these maximums appears at the length ratio θ = 0.5. This implies that in contrast to π-TEGs, the Linear-TEG has a better thermoelectric performance. Meanwhile decreasing the total length and/or increasing the height can improve the power. Interestingly, under the large temperature difference, there is a nonlinear relationship between the power and the height, and the optimal length ratio corresponding to maximum efficiency is dependent to the total length and height of the thermoelements, which are different to that under the small temperature difference. Our work will provide an alternative way for the design of high performance thermoelectric generators.