Thermo-ecological analysis and optimization of a three-heat-reservoir absorption heat pump with two internal irreversibilities and external irreversibility

Abstract

The investigations carried out in this work concern the optimization and the thermodynamic analysis of an absorption heat pump with multi-irreversibilities and provided with three-heat-reservoir mainly using the thermo-ecological criterion as objective function. The thermodynamic analysis of the first and second laws of thermodynamics and the linear law of heat-transfer allowed us to evaluate and optimize the objective functions of performance such as: the specific heating load, the coefficient of performance, the specific entropy generation rate, the ecological coefficient of performance and the heat-transfer areas of the various components. These allowed us to study the variations of these criteria according to the design parameters and the temperatures of the working fluid in the components. From this study, it follows that the optimal system implies a maximum thermo-ecological coefficient, a minimum entropy production rate corresponding to a certain value of the specific heating load, while maintaining a system which limits the losses between the condenser and the evaporator. Moreover, the consideration of the two internal irreversibilities, the external irreversibility and the losses of the heat resistances is very close to a real absorption heat pump and allows a more precise and objective study rather than in the optimization and the design of an absorption system like an endoreversible system.