The Environmental Protection Agency (EPA) is pushing to approve a new automotive air conditioning refrigerant — HFO-1234yf — in its Significant New Alternatives Policy Program (SNAP) because both the EPA and the Department of Transportation want auto manufacturers to reduce greenhouse gas emissions.
The proposed rule would designate 1234yf as a substitute for CFC-12 and R-134a. The current refrigerant of choice, R-134a has a global warming potential (GWP) of 1,430 compared to HFO-1234yf’s GWP of 4. Once the EPA approves 1234yf in its SNAP, it would have to approve the refrigerant also as a new chemical entity as part of its Toxic Substances Control Act (TSCA) program.
The emergence of 1234yf won’t have much effect initially on aftermarket retailers or non-OEM service providers. However, phasing out 134a over the years will lead to reduced sales of those canisters, and those store facings may not be replaced with canisters of 1234yf. There are concerns about 1234yf’s flammability, especially when considering the “do-it-yourself” market. So long-term replacement refrigerant may be removed from the aftermarket, unless some sort of “fix” is found.
At the moment, 1234yf is only an OEM issue. Japan is the first country to approve the new refrigerant for use in vehicle AC systems. Toyota and Nissan will use it in new platforms going forward, particularly in the European Union, which requires new platforms introduced in member countries after January 2011 to use low global warming refrigerants. The U.S. currently has no such requirement. But global warming, caused in part by greenhouse gas emissions, comes into play big time in the current EPA and DOT rulemaking setting national Corporate Average Fuel Economy (CAFE) standards for 2012-2016. For the first time, these CAFE standards will also force automakers to reduce emissions of GHGs, and give them credits when those reductions come from vehicle AC systems. But GM, Ford, Toyota and others are waiting for an EPA green light before moving forward.
The beautiful thing about 1234yf is that it is a “near” drop-in replacement for 134a, meaning OEMs do not have to do much re-engineering of AC systems themselves, according to Tom Morris, director, commercial developments, refrigerants, Honeywell, Inc. Again, the major concern with 1234yf is its potential flammability, which is much greater than 134a. For example, emissions of HFO-1234yf do lead to some minimal creation of ground-level ozone, which is a smog contributor, of course.
If released into the interior of a car, and if an ignition source were present, 1234yf could start a fire. There is also a possibility of fires outside the passenger compartment because of heat from the exhaust manifold. EPA has suggested some “use conditions” for vehicle manufacturers, such as a requirement for protective devices under the vehicle hood to keep the refrigerant and hot exhaust manifold surfaces separated. ?
