Thermodynamic optimization for work-assisted heating and drying operations

We construct thermodynamic criteria for optimization of sequential work-assisted heating and drying operations which run jointly with ‘endoreversible’ thermal machines. The total power input is minimized with constraints which take into account the dynamics of heat and mass transport and rate of work consumption. Finite-rate, endoreversible models include the irreducible losses of classical exergy potential caused by the thermal resistances. Extremum performance functions for optimal work, which incorporate residual entropy production, are formulated in terms of end states, duration and (in discrete processes) number of stages. Formal analogies between entropy production expressions for work-assisted and conventional drying operations help formulate optimization models of the former. An optimization procedure for a two-stage drying operation with an endoreversible heat pump at each stage is outlined.