Performance evaluation of HFO-based ionic liquid pairs for double-effect absorption refrigeration system.

This paper investigates double-effect absorption refrigeration systems (DEARS) using hydrofluoroolefin (HFO) refrigerants and ionic liquid (IL) absorbents. Thermodynamic models were developed, focusing on enthalpy and vapor-liquid equilibrium (VLE) characteristics, to identify efficient refrigerant-absorbent pairs. Among evaluated pairs, R1234ze(Z)/[BMIM][SCN] and R1336mzz(Z)/[OMIM][BF4] demonstrated superior performance due to their significant concentration differences between weak and strong solutions, measured at 0.0998 and 0.0565, respectively. System performance analysis based on the high-pressure generator conditions showed that these pairs achieved coefficients of performance (COP) of approximately 0.91 for R1234ze(Z)+[BMIM][SCN] and 0.66 for R1336mzz(Z)+[OMIM][BF4]. Results indicated notable COP improvements with increased high-pressure generator temperatures. This study provides valuable insights for selecting environmentally friendly refrigerant-absorbent pairs, enhancing the efficiency and sustainability of DEARS.