The ionic liquids have offered a new way for improving working substance of absorption refrigeration cycle. However

the performance of the absorption refrigeration cycle with ionic liquids and water as working pairs is strongly dependent on the hygroscopy of ionic liquids. Two ionic liquids: 1-ethyl-3-methylimidazolium acetate ([EMIm]Ac) and 1-hexyl-3-methylimidazolium chloride([HMIm]Cl)

which have super water-absorption capability

were selected as the working pairs for absorption refrigeration cycles. First

we studied the thermodynamic properties (vapor pressure

specific heat

enthalpy

etc.) of the two ionic liquid aqueous solutions. Then we analyzed their coefficient of performance for the absorption refrigeration cycle. The study shows the two ionic liquid-water pairs can work in a higher temperature condition for single-stage absorption refrigeration cycles and have better coefficients of performance (COP) comparing to those of the ionic liquid working pairs studied by the existed works of other domestic and foreign scholars. The performance of [EMIm]Ac aqueous solution is superior to that of [HMIm]Cl. Comparing to the performance of the ordinary lithium bromide-water working pair

the COP of the single-stage absorption cycle of [EMIm]Ac aqueous solution is almost the same when the generation temperature reach 100℃

and for higher temperature range

the performance of [EMIm]Ac-water pair is a little superior to that of the ordinary lithium bromide-water working pair. Since the superiority of the ionic liquid is only in higher generation temperature

further breakthrough should be had for good properties of vapor pressure of ionic liquid in the low temperature.