Performance evaluation of HFO/Ionic-liquid working pairs for single-effect and compression-assisted absorption refrigeration cycles

This study evaluates the application potential of four low-GWP HFO/ionic-liquid working pairs in absorption refrigeration systems. The NRTL activity coefficient model was used to describe vapor-liquid equilibrium, and thermodynamic models of single-effect and compression-assisted absorption cycles were established. The effects of generator, absorber, condenser, and evaporator temperatures on circulation ratio, solution concentration difference, COP, and exergy efficiency were analyzed. Results show that higher generator and evaporator temperatures generally improve cycle performance within the feasible operating range, whereas higher absorber and condenser temperatures have adverse effects. Among the investigated pairs, R1234ze(E)/[C4mim][DCA] exhibits the most favorable thermodynamic performance. Compression assistance increases the absorption pressure, reduces the circulation ratio, and extends the feasible operating range, particularly under low-grade heat-source conditions. The main contribution of this study is the systematic comparison of HFO/[DCA] working pairs and two cycle configurations under a consistent thermodynamic framework. The results provide a basis for working-pair screening and operating-condition optimization for low-grade-heat-driven absorption refrigeration. Further experimental validation, transport-property characterization, and system-level optimization are required to assess the practical applicability of these working pairs.