以离子液体为吸收剂的吸收式制冷循环热力学分析

Thermodynamic analysis of absorption refrigeration cycles using ionic liquids as absorbents

分析了R161/[hmim][Tf2N]、R32/[emim][Tf2N]、R290/[emim][BF4]三种工质对的热力学性能;采用NRTL模型对制冷剂/离子液体的汽液相平衡数据进行了关联;探讨了发生器出口温度、蒸发器出口温度及吸收温度对循环比、COP及?效率的影响。R32/[emim][Tf2N]和R161/[hmim][Tf2N]的COP相近,R290/[emim][BF4]的COP最小;在蒸发温度、吸收温度分别是5、25℃时,R32/[emim][Tf2N]系统的COP随着发生温度的变化可达到0.59以上,R290/[emim][BF4]的COP低于0.1;降低吸收温度可以扩大循环的可行温度,提高COP;蒸发温度为5℃,吸收温度从30℃降低到25℃,COP可提高1.4倍以上。

The thermodynamic performances of three working pairs(R161/[hmim][Tf2N],R32/[emim][Tf2N]and R290/[emim][BF4])have been analyzed.Non-Random Two-Liquid(NRTL)model was used to correlate the vapor-liquid equilibrium data of refrigerants/ionic liquids.The effects of generator outlet temperature,evaporator outlet temperature,absorption temperature on the circulation ratio,COP and exergetic coefficient of performance(ECOP)have been discussed.The COP of R32/[emim][Tf2N]system is close to that of R161/[hmim][Tf2N]system and the COP of R290/[emim][BF4]is the lowest.When the evaporation temperature is 5℃ and the absorption temperature is 25℃,the COP of R32[emim][Tf2N]system reaches more than 0.59.However,the COP of R290 is always less than 0.1.Upon reducing the absorption temperature,it can expand the feasible temperature of the cycle and improve the COP.When the evaporation temperature is 5℃ and the absorption temperature is reduced from 30℃to 25℃,the COP increases more than 1.4 times.