Irreversible thermodynamics of ATMEC devices

The principles and techniques of reversible thermodynamics are unable to describe the process and phenomena that occur in AMTEC devices. The process of energy conversion, in general, and in particular the operation of the beta alumina solid electrolyte (BASE) produce dynamic changes of state. In this paper irreversible thermodynamics is used in an attempt to describe these dynamic changes through the derivation of the appropriate entropy balance equation. To describe the transport (diffusion) of sodium cations through the BASE the Onsager reciprocal relations are used. The phenomenological equations derived from Onsager Relations are of limited value in practical calculations. Therefore the dissipation function is transformed to obtain the forces related to the fluxes by simple parameters, some of which are constant in range of AMTEC operation as shown by experiment.