The implications of residential air conditioning refrigerant choice on future hydrofluorocarbon consumption in the United States.

Abstract

As the primary alternative to ozone-depleting refrigerants, hydrofluorocarbons (HFCs) have increased in use and emissions in the United States. A significant increase in this use and emissions, and a large portion of total U.S. HFC consumption, is expected due to the use of HFCs in residential air conditioning (RAC). The RAC market primarily relied upon chlorodifluoromethane, a hydrochlorofluorocarbon (HCFC) commonly referred to as HCFC-22, whose consumption is being phased out globally under the Montreal Protocol on Substances that Deplete the Ozone Layer and under national regulations such as the Clean Air Act in the United States. The RAC market today relies on HFCs, most often R-410A (a blend of difluoromethane, known as HFC-32, and pentafluoroethane, known as HFC-125) for new equipment, but older units using HCFC-22 remain to be replaced. The RAC industry is investigating multiple alternatives with global warming potentials (GWPs) significantly below that of R-410A. Research has been conducted by chemical producers, air conditioner and component manufacturers, national government laboratories, academia, and consortium efforts such as the Low-GWP Alternative Refrigerants Evaluation Program administered by an industry trade organization. Various low-GWP alternatives have been suggested with GWPs of approximately 750 and below. This paper models HFC consumption in the United States and investigates industry-wide HFC reduction measures across sectors that have transitioned from ozone-depleting substances to HFCs. Under various scenarios of such measures, this paper shows that future RAC refrigerants will strongly influence industry efforts to reduce U.S. HFC consumption. RAC refrigerants with GWPs in the 150-750 range are investigated to estimate future HFC consumption levels in the United States. The transition to refrigerants with GWPs in the 150-750 range can provide significant reduction in HFC consumption in the United States. These reductions are not just reliant on manufacturers introducing new equipment with low-GWP alternatives. The service industries, responsible for repairing leaks and recovering refrigerant, play a vital role in reducing HFC consumption.