Performance Simulation of Ionic Liquid and Hydrofluorocarbon Working Fluids for an Absorption Refrigeration System

The theoretical performance of ionic-liquid- (IL-) based working fluids in an absorption refrigeration system was investigated. The IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and five hydrofluorocarbons (HFCs) were selected as the absorbent and refrigerant, respectively. The Redlich-Kwong equation of state and two-phase pressure-drop model were used to compute the thermodynamic conditions and performance of the working-fluid pairs. The effects of the desorber and absorber temperatures, solution heat exchanger, and accessibility of waste heat on the system performance were evaluated. R152a showed the highest coefficient of performance, 57.3, when the desorber operated on waste heat only and the desorber and absorber were operated at 373.15 and 300.65 K, respectively. The friction-loss component of the total pumping work was below 2.5% of the pumping work for all refrigerants.