Energy performance investigation and life cycle assessment on a modified dual-evaporator refrigeration system using novel CO2/HFO mixture

Cold chain plays an important role in the improvement of living standards, in which dual-evaporator refrigeration system (DRS) is extensively adopted for energy conservation and emission reduction. However, traditional DRS suffers from drawbacks in adaptability due to complex configuration, and flammability or global warming potential due to defective refrigerants. To address the demand for safe and eco-friendly DRS, a modified dual-evaporator refrigeration system (MDRS) utilizing CO₂/HFO mixture is proposed in this study. The energy efficiency and flammability of different CO₂/HFO mixtures are compared, highlighting a promising performance of CO₂/R1336mzz(E). The energy performance of MDRS is compared with two typical systems, in which an improvement of up to 91% is achieved. Consequently, MDRS shows higher annual performance factors in most cities worldwide, with the highest superiority of 45% in Bangkok. Exergy analysis suggests that the energy performance improvement is attributable to the reduction of throttling irreversibility. A life cycle assessment is conducted to evaluate the economic and environmental performances. MDRS exhibits superiority in life cycle cost (LCC) and life cycle climate performance (LCCP), with maximum reductions of 34% and 31%. An exergo-economic analysis further confirms the economic advantages of MDRS, while its advantages in safety and regulation are also discussed. This study contributes to: 1) providing an efficient, safe, cost-effective and eco-friendly option for cold chain refrigeration; 2) promoting energy conservation and emission reduction for climate governance worldwide.