Ammonia/water absorption cycles with relatively high generator temperatures

Abstract

The advent of evacuated tubular collectors, with their capacity for delivering heat in excess of 100°C at reasonable efficiency, has prompted investigation of the potential for absorption cycles employing higher generator temperatures than usual. The single-stage cycle and two high-performance cycles, termed the fat single-stage cycle and the two-stage cycle, are analyzed, with the single-stage and the two-stage cycles appearing to have the better prospects for incorporation into systems. Using improved heat transfer equipment which is under development, COPs of the order of 0.8 ought to be possible for single-stage cycles, and 1.3 for two-stage cycles, at peak generator temperatures of the order of 100 and 170°C respectively. The improved performance of the two-stage cycle should permit an improvement in overall steady-state system performance when this cycle is used in conjunction with evacuated tubular collectors, at the cost of increased system complexity.