Performance prediction of absorption refrigeration cycle based on the measurements of vapor pressure and heat capacity of H2O + [DMIM]DMP system

Abstract

In this paper, the thermophysical properties of the H2O+1,3-dimethylimidazolium dimethylphosphate ([DMIM]DMP) system were studied. The boiling point method was adopted to measure the vapor pressures of the system at mass fraction of ionic liquids (ILs) in the range from 0.10 to 0.90 as well as pressures range from 2kPa to 101kPa. And the general non-random two-liquid (NRTL) activity coefficient model was used to correlate the experimental data. The heat capacities of the system were determined by a BT2.15 Calvet microcalorimeter at mass fraction of ILs in the range from 0.10 to 0.90 and temperatures range from 303.15K to 353.15K. A polynomial equation on temperature and concentration was correlated with satisfactory results. And then theoretical analysis of the coefficient of performance (ω) of a single-effect absorption refrigeration cycle was simulated using H2O+[DMIM]DMP as working pair on the basis of the models of vapor pressure and heat capacity. The simulation results show that the ω of H2O+[DMIM]DMP system is close to that of conventional working pair H2O+LiBr. In addition, the H2O+[DMIM]DMP system improved the limitations of crystallization and corrosion of H2O+LiBr system.