Minimal Entropy Production and Efficiency of Energy Conversion in Nonlinear Thermoelectric Systems with Two Temperatures

In this paper we determine the physical conditions ensuring that the efficiency of a thermoelectric nanowire with two temperatures is optimal. We consider the case in which the entropy for unitary volume depends on the equilibrium variables only, and the case in which such a quantity depends on the dissipative fluxes, too. We prove that in these two different situations the conditions of optimal efficiency are different.