Optimum performance characteristics of an irreversible absorption refrigeration system

On the basis of the endoreversible model of absorption refrigeration cycles, a new cycle model, which includes the heat leak from the heal sink to the cooled space and irreversibilities due to the internal dissipation of the working fluid besides the finite-rate heat transfer between the working fluid and the external heat reservoirs, is established and used to calculate the maximum coefficient of performance and cooling rate of the absorption refrigeration system for a given total heal-transfer area of the heat exchangers. The temperatures of the working fluid and the distribution of the heat-transfer areas of the heat exchangers are optimized for the two states of maximum coefficient of performance and maximum cooling rate. The behavior of the dimensionless specific cooling rate as a function of the coefficient of performance is presented, which may be used to describe the general performance characteristics of an irreversible absorption refrigerator. The practical operating regions of the cycle system are determined and the new bounds of the primary performance parameters are given. (C) 1998 Elsevier Science Ltd. All rights reserved.