基于水蒸气工质新型压缩-吸收式热泵循环性能分析

针对常规热泵在工业余热利用领域应用温度范围受限的技术难题,该文对一种压缩-吸收式耦合热泵系统在大温升工况下制取约130 ℃热水或蒸汽开展研究。首先介绍耦合热泵循环的运行原理,构建耦合热泵的完整热力学模型,通过EES软件最优化函数计算发现吸收侧压力越低,循环性能系数（COP）越好,同时在溶液热交换器出口浓溶液温度高于结晶温度10 ℃及溶液放汽范围为5.0%~5.5%的约束条件下,以某工业余热回收工况为设计工况,其中余热热水进/出口温度为90/75 ℃,余热水流量为30 kg/s,高温热水进/出口温度为100/125 ℃,吸收与发生侧最优压力值分别为40和2.2 kPa,对应耦合热泵的COP为9.8。同理分析了不同余热热水出口温度及高温热水出口温度变化工况下系统的循环性能,验证了该循环在高制热温度下仍具有较好的性能系数。

PERFORMANCE ANALYSIS OF NEW COMPRESSION ABSORPTION HEAT PUMP CYCLE BASED ON STEAM WORKING MEDIUM

Aiming at the technical problem of limited temperature range in the application of conventional heat pump in the field of industrial waste heat utilization, this paper studies the production of about 130 ℃ hot water or steam by a compression-absorption coupled heat pump systems under the condition of large temperature rise. In this paper, the operation principle of coupled heat pump cycle is introduced, and the complete thermodynamic model of coupled heat pump is constructed. Through the optimization function calculation of EES software, it is found that the lower the absorption side pressure is, the better the cycle COP is. At the same time, under the constraint conditions that the temperature of concentrated solution at the outlet of solution heat exchangers is 10 ℃ higher than the crystallization temperature and the range of solution steam discharge is 5.0%-5.5%, taking an industrial waste heat recovery condition as the design condition, the results show that the inlet and outlet temperature of waste heat hot water is 90/75 ℃, the flow rate of residual hot water is 30 kg/s, the inlet and outlet temperature of high temperature hot water is 100/125 ℃, the optimal pressure values of absorption and generation side are 40 kPa and 2.2 kPa respectively, and the COP of the corresponding coupled heat pump is 9.8. In the same way, the cycle performance of the system with different outlet temperature of waste heat hot water and high temperature hot water outlet is analyzed, and it is verified that the cycle still has good virtual performance coefficient at high heating temperature.