Influence of nonlinear effects on the efficiency of a thermoelectric generator

We propose a nonlinear model for thermoelectric coupling which is based on the thermomass theory for heat conduction. We show that in this model, the second Kelvin relation and the classical Onsager relations are no longer satisfied simultaneously, namely, if one holds, then the other one breaks down, and viceversa. As a function of the different breaking, we evaluate the efficiency of a thermoelectric generator. The influence of the electric-charge gradient on the efficiency of thermoelectric coupling is investigated as well.