Performance of real absorption heat-transformer with a generalized heat transfer law

Abstract

An irreversible four-temperature-level absorption heat-transformer cycle model with a generalized heat transfer law of Q ∝ Δ( T n ) ( n ≠ 0) is established, which considers effects of heat resistance, heat leak and internal irreversibilities. The general relation between the COP (coefficient of performance) and the heating load is deduced. The fundamental optimal relation and the performance limit, the optimal temperatures of working substance, as well as the optimal heat transfer surface area distributions with linear phenomenological heat transfer law are derived. Moreover, effects of heat transfer law, heat leak, and internal irreversibilities on the performance of absorption heat-transformer are analyzed; and the performance comparison is performed for the distribution of the total heat transfer surface area is optimized or not by numerical example. The results obtained herein are useful for optimal design and performance improvement of absorption heat-transformer cycles.