离子液体基工质对的吸收制冷循环性能实验研究

摘要

The performance test of the absorption refrigeration cycle with ionic liquid , 1-ethyl-3-methylimidazolium diethylphosphate [Emim][DEP]-based binary working pairs [Emim][DEP]+H2O and ternary working pairs LiBr+ [Emim][DEP] + H2O were conducted in order to evaluate the refrigeration effects of this new ionic liquid-based working pairs. The experiment results showed that the ionic liquid-based working pairs [Emim][DEP]+H2O was capable of refrigeration. Compared with the working pairs LiBr+H2O,[Emim][DEP]+H2O lowered the performance coefficient of refrigeration cycle due to its lower thermal conductivity and higher viscosity which led to absorbing water steam ability of [Emim][DEP]+H2O in absorber more weak under the same size of absorber. When the generation temperature and cooling water temperature were 90℃ and 30℃,respectively,the evaporation temperature was in the range of 10 to 15℃,the performance coefficient of refrigeration cycle varied from 0.16 to 0.28. In order to enhance the absorbing ability to water steam in absorber and consequently to real performance of absorption refrigeration cycle,small amount of solution LiBr+ H2O was added into the [Emim][DEP]+H2O and constituted ternary working pairs LiBr+ [Emim][DEP]+H2O, the experiment results showed that the performance coefficient of refrigeration cycle of ternary working pairs LiBr+ [Emim][DEP]+H2O was superior to that of [Emim][DEP] + H2O,and varied from 0.17 to 0.34 when the evaporation temperature was in the range of 10℃ to 15℃.%分别对以离子液体 1-乙基-3-甲基咪唑磷酸二乙酯[Emim][DEP]为吸收剂的二元工质对[Emim][DEP]+H2O和以[Emim][DEP]+LiBr为吸收剂的三元工质对LiBr+[Emim][DEP]+H2O的吸收制冷循环性能进行了实验研究,用于评价这种新型的工质对的制冷性能.实验结果表明,二元工质对[Emim][DEP]+H2O 具有吸收制冷性能,但与LiBr+H2O工质对相比,其制冷系数较低.当发生温度为90℃、循环水温度为30℃、蒸发温度在10～15℃时,制冷系数仅为 0.16～0.28.主要原因是[Emim][DEP]+H2O 工质对具有较高的黏度和较低的热导率,导致吸收器降膜吸收传热系数较低,吸收器吸收水蒸气的能力不足.为了强化其制冷效果,在[Emim][DEP]+H2O 工质溶液中加入少量 LiBr 水溶液,构成三元工质对 LiBr+[Emim][DEP]+H2O .实验结果表明,三元工质对LiBr+[Emim][DEP]+H2O 的制冷性能优于二元工质对[Emim[DEP]+H2O,在上述蒸发温度范围内,制冷系数能够达到0.17～0.34,并且制冷温度更低.