Combined Effects of Refrigerant Substitutions of Residential Air Conditioners and Improvement in Lifecycle Refrigerant Management on Reduction of Global Greenhouse Gas Emissions

This study analyzes the effects on global greenhouse gas (GHG) emissions of various combinations of lifecycle refrigerant management (LRM) practices and refrigerant substitutions in residential air conditioners (ACs) until the year 2070. Six scenarios involving three refrigerant types with different levels of global warming potential (GWP)—high, medium, and ultralow—and three levels of LRM involving leakage reduction during operation and end-of-life refrigerant recovery are examined. The findings reveal that combining medium GWP refrigerants (e.g., R32) with the highest level of LRM could achieve as much as a 95% reduction in emissions (933 MtCO2eq) by 2050 and a 97% reduction (1660 MtCO2eq) by 2070, when compared to using high GWP refrigerants (e.g., R410A). The substitution of ultralow GWP refrigerants (e.g., R290) is projected to achieve up to a 97% emissions reduction (954 MtCO2eq) by 2050 and a 100% (1709 MtCO2eq) reduction by 2070. Global mean temperature decreases in 2070 are nearly identical under scenarios in which either medium GWP refrigerants or ultralow GWP refrigerants are combined with the highest level of LRM (0.067 °C versus 0.069 °C). The implication is that combining medium GWP refrigerants, already underway in some regions, with the highest level of LRM offering an effective and pragmatic strategy for mitigating the climate impacts of refrigerant emission from residential ACs.