Analysis and evaluation of 2,2,2- trifluoroethanol/ionic liquids as new

Abstract

In this work, the performance of new proposed 2,2,2-trifluoroethanol/ionic liquid mixtures for absorption heat transformer applications is studied. The 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4] have been selected as new absorbent for absorption heat transformer systems with 2,2,2- trifluoroethanol (TFE) as refrigerant. The selection of these ionic liquids is based on a computationalexperimental study to select suitable ionic liquids with optimized properties for TFE absorption applications. The performance of these two TFE/ionic liquid mixtures is analysed and evaluated. The solution concentration (i.e. refrigerant in ionic liquids) in absorber and generator are predicted based on experimental vapour-liquid equilibrium data. The experimental data of both vapor liquid equilibrium and excess enthalpy of the mixture are correlated using Non-Random Two Liquid (NRTL) method available in Aspen Plus software. The performance indicators, such as coefficient of performance and solution mass flow rate are studied and analyzed. The simulation results show that the new proposed working fluid of TFE/[bmim][BF4] and TFE-[emim][BF4] are suitable for absorption heat transformer applications. The COP of new proposed TFE-ionic liquid working pairs is slightly lower than conventional waterlithium bromide working fluid. However solution mass flow ratio of the new proposed working fluids gives better values as compared to conventional water-lithium bromide working pair. The TFE/[bmim][BF4] working pair gives better performances as compare to the TFE/[emim][BF4] working pair.