Impact of internal connections and heat loss on simulated large-scale low-temperature thermoelectric generation system

Thermoelectric generator (TEG) has been demonstrated as a desirable technology for deeply harvesting low-temperature waste heat discharged from industrial processes. Due to the multilayer hollow structure, the internal connection-and-contact (ICC) effects and heat loss can cause considerable performance degradation in TEGs. In this study, a two-dimensional thermal-electrical model is established to realize multi-parameter optimization of large-scale plate TEG systems including the ICC layers and heat transfer coefficient on the TEG surfaces. The ICC effects are identified for different side-surface heat transfer coefficient, by using gradient search method to match with the experimental data. The results show that, the ICC effects have significant impact on maximum output power and optimal design parameters in the TEG, while impact of the side-surface heat transfer coefficient is not significant. In the model without ICC effects and heat loss, when the thermoelement length increases, the maximum output power changes negligibly, and corresponding cost-to-power ratio increases monotonously. However, when the ICC effect is coupled with the side-surface heat transfer coefficient, the maximum output power increases significantly while the cost-to-power ratio varies non-monotonously. Therefore, considering the real ICC effects is crucial for optimum design of large-scale TEG systems operating at low temperatures.