The performance of [Emim]Br/H2O as a working pair in the absorption refrigeration system

Abstract

The energy efficiency of the single-effect absorption refrigeration systems (ARS) using ionic liquid (IL) [Emim]Br as an absorbent and water as a refrigerant is evaluated in this study. The thermodynamic properties of the mixture, such as vapor pressures and excess enthalpies, are calculated using the non-random two-liquid (NRTL) activity coefficient model. The coefficient of performance (COP) is estimated with fixed temperatures for the evaporator, absorber, condenser, and generator, set at 10, 30, 40, and 100 °C, respectively. It is found that the COP of the single-effect ARS using [Emim]Br-H2O as the working pair is about 0.8, which is slightly lower than that obtained with LiBr-H2O (0.83), but much higher than that of H2O-NH3 (0.65) systems. The effect of generator temperature on COP has the same trend as that of other IL working pairs. The influence of each component temperature on the system’s performance is investigated, and it is found that the single-effect ARS performs very well under different conditions with [Emim]Br - H2O as the working pair.