溶液加冷剂回热双吸收式热变换器循环性能分析

Performance analysis of double absorption heat transformers with solution and coolant heat regeneration cycle

基于溶液回热双吸收式热变换器循环,提出了一种溶液加冷剂回热双吸收式热变换器循环方案,即在溶液回热双吸收式热变换器的吸收蒸发器稀溶液出口增加了一个溶液与冷剂间的热交换器.计算并比较了吸收蒸发器稀溶液出口溶液无回热、有溶液回热以及同时有溶液和冷剂回热3种双吸收式热变换器循环的性能系数和效率.结果表明,溶液加冷剂回热双吸收式热变换器循环不仅具有较宽的吸收蒸发温度变化范围,而且在整个吸收蒸发器操作范围内可使循环性能系数和效率进一步提升,当吸收温度、发生温度、冷凝温度和吸收蒸发温度分别为120~150,70,25和80~115℃时,性能系数和效率较有溶液回热双吸收式热变换器循环增加约2.5%~3.5%.同时分析了吸收温度、冷凝温度、发生温度和吸收蒸发温度变化时吸收蒸发器稀溶液出口无回热、有溶液回热以及同时有溶液和冷剂回热3种循环的性能系数和效率的变化趋势.

Based on the cycle of double absorption heat transformer with solution heat regeneration,a modified cycle of double absorption heat transformer with both solution and coolant heat regeneration was proposed by adding a heat exchanger between solution and coolant at the outlet of dilute solution of the absorber-evaporator.Both coefficients of performance(COP)and exergy efficiencies of three kinds of cycles in double absorption heat transformers without heat regeneration,with solution heat regeneration and with both solution and coolant heat regeneration at the outlet of dilute solution of the absorber-evaporator were calculated and compared.The results show that the new cycle of double absorption heat transformer with solution and coolant heat regeneration has a wider operating range of absorption-evaporation temperature and higher COP and exergy efficiency in the discussed scope.When the temperatures of absorption,generation,condensation and absorption-evaporation are120to150,70,25and80to115°C,respectively,the COP and exergy efficiencies of the new cycle increase by about2.5%to3.5%compared with those of the one with solution heat regeneration only.The variation trends of COP and exergy efficiency of the three cycles versus the temperatures of absorption-evaporation,condensation,generation and absorption are analyzed.