Performance analysis of a closed regenerated brayton heat pump with internal irreversibilities

This paper analyses the performance of a real heat pump plant via methods o f entropy generation minimization or finite-time thermodynamics. The analyt ical relations between heating load and pressure ratio, and between coeffic ient of performance (COP) and pressure ratio of real closed regenerated Bra yton heat pump cycles coupled to constant- and variable-temperature heat re servoirs are derived. In the analysis, the irreversibilities include heat t ransfer-irreversible losses in the hot- and cold-side heat exchangers and t he regenerator, the non-isentropic expansion and compression losses in the compressor and expander, and the pressure drop loss in the pipe and system. The optimal performance characteristics of the cycle may be obtained by op timizing the distribution of heat conductances or heat transfer surface are as among the two heat exchangers and the regenerator, and the matching betw een working fluid and the heat reservoirs. The influence of the effectivene ss of regenerator, the effectiveness of hot- and cold-side heat exchangers, the efficiencies of the expander and compressor, the pressure recovery coe fficient and the temperature of the heat reservoirs on the heating load and COP of the cycle are illustrated by numerical examples. Published in 1999 by John Wiley & Sons, Ltd.