A primer in theoretical physics applied to thermoelectricity

A basic knowledge about theoretical physics is required to understand why a thermoelectric material is better than another. This article popularizes the key concepts required to calculate the transport properties in thermoelectric materials. Instead of starting with electrons and phonons we explain how to calculate the energy flux and the thermal conductivity in a gas of molecules. By doing so the subtractions of the distribution function at the non- thermodynamically at the equilibrium, which enter in the calculation of the Figure-of-Merit is introduce intelligibly. The Boltzmanns equation, which is used to calculate the Figure of Merit is derived by distinguishing the equilibrium state and the steady state. The profile of the ideal thermoelectric material is draw up.