Performance optimization of a class of combined thermoelectric heating devices

A detailed model of thermally-driven combined thermoelectric (TE) heating device is established. The device consists of two-stage TE heat pump (TTEH) and two-stage TE generator (TTEG) with four external heat exchangers (HEXs). Both internal losses and external heat transfer irreversibilities are considered in the model. The heating capacity and the coefficient of performance (COP) of the device are improved through numerical optimization, which is of great significance to the application of the device. The distribution of the total TE element number among four TE devices and the distribution of the total external heat conductance among the four external HEXs are optimized. The results show that both the reservoir temperatures of TTEG and TTEH have significant influences on the performance and the corresponding optimum parameters of the device. The COP can reach 0.14 after optimization when the temperature difference of heat source is 150 K and the temperature difference of heating is 10 K.