Theoretical Analysis of the Thermoelectric Generator Considering Surface to Surrounding Heat Convection and Contact Resistance

A general theoretical model of thermoelectric generation (TEG) is proposed based on the one-dimensional steady heat transport in this paper. The effect of heat convection between the thermoelectric legs and the ambient environment, and contact resistance between the heat reservoirs and thermoelectric couple on the performance of the TEG is studied. Fundamental formulas and closed-form solutions for the output power and conversion efficiency are derived. Numerical results show that the maximum output power and maximum conversion efficiency of the TEG are lower than those of the ideal TEG when the influence of heat convection and contact resistance are taken into consideration. The heat convection has a very small effect on the maximum output power, but causes a large reduction of conversion efficiency for the TEG, and this reduction becomes more significant as the length of thermoelectric couple increases. In addition, there always exists an optimum length of thermoelectric couple for the actual TEG, so as to achieve the maximum conversion efficiency when the effects of heat convection together with contact resistance are considered. The results of this paper may help to improve the design and optimization of TEG devices.