  Thermoelectricity is traditionally explained via Onsager's irreversible,
flux-force framework. The coupled flows of heat and electric charge are
modelled as steady-state flows, driven by the thermodynamic forces defined in
terms of the gradients of local, intensive parameters like temperature and
electrochemical potential. A thermoelectric generator is a device with a finite
extension, and its performance is measured in terms of total power output and
total entropy generation. These global quantities are naturally expressed in
terms of discrete or global forces derived from their local counterparts. We
analyze the thermodynamics of thermoelectricity in terms of global flux-force
relations. These relations clearly show the additional quadratic dependence of
the driver flux on global forces, corresponding to the process of Joule
heating. We discuss the global kinetic coefficients defined by these flux-force
relations and prove that the equality of the global cross-coefficients is
derived from a similar property of the local coefficients. Finally, we clarify
the differences between the global framework for thermoelectric energy
conversion and the recently proposed minimally nonlinear irreversible
thermodynamic model.
