Performance analysis of a two-stage irreversible heat pump under maximum heating load per unit total cost conditions

A performance optimization of a two-stage irreversible combined heat-pump system has been carried out. The irreversibility of heat transfer across finite temperature differences, the heat-leak loss between the external heat reservoirs and the internal dissipation of the working fluids are considered. The heating load per unit total cost is taken as an objective function for the optimization. The maximum of the objective function and the corresponding optimal performance and design parameters have been derived analytically. The global and the optimal performance characteristics curves are presented in terms of technical and economical parameters. The irreversibility effects and economical aspects on the general and optimal performances have been investigated.