Comparison and parametric study of two theoretical modeling approaches based on an air-to-water thermoelectric generator system

Numerical model and thermal resistance model are two commonly used modeling approaches to analyze the performance of thermoelectric devices. However, a great number of assumptions and simplifications are made in previous researches. This work presents a steady state and fluid-thermal-electric multi-physical numerical model and improves the conventional thermal resistance model to investigate the performance of an air-to-water thermoelectric generator system. In considering the multi-physical field coupling effects and temperature dependent thermoelectric material properties, the comparison of these two theoretical models and parametric investigation on the thermoelectric generator system are conducted. The results indicate that the thermal resistance model can be used to preliminarily evaluate the performance of thermoelectric generator system with acceptable accuracy at appropriate working conditions, but more precisely, the numerical model should be adopted. Besides, the heat losses should not be omitted in the theoretical analysis, and an optimal load resistance must be chosen between the maximum power one and the maximum conversion efficiency one. The findings of this work can guide the future theoretical analysis of the thermoelectric generator system by numerical model or thermal resistance model.