Exploring the 4E characteristics of low GWP mixed refrigerants in solar-powered vapor-injection air conditioning cycle

In the urgent context of global energy transition and climate governance, the efficient and low-cost solar cooling technologies is crucial. The Solar-Powered Vapor-injection Air Conditioning Cycle (SP-VIAC) offers a promising solution, but its overall performance is highly sensitive to refrigerant choice and operating parameters, necessitating comprehensive optimization from energy, exergy, economic, and environmental (4E) perspectives. This study proposes an improved SP-VIAC cycle and, for the first time, integrates multi-objective optimization with a 4E analysis framework to evaluate six low GWP mixed refrigerants based on R290. Results show that optimizing mixture composition and operating conditions significantly enhances system performance. The R290/R1234yf mixture achieves the highest coefficient of COP (1.29) at 27.3% R290, with excellent stability. Major exergy destruction occurs in the solar collector and ejector, accounting for over 84% of total losses. Economic and environmental analysis indicates R290/R1234ze(E) has the lowest operating cost, while R290/R1234yf has the lowest LCCP. Multi-objective optimization reveals trade-offs between performance targets and R290/R1234yf (45% R290) achieves the best balance among energy efficiency, exergy efficiency, cost, and carbon emissions. This study provides a multi-criteria decision-making basis for the refrigerant selection and collaborative systems design, promoting the advancement of this technology towards practical low-carbon applications.