A study has found that Honeywell’s low-global-warming refrigerant, HFO-1234yf, has a global-warming potential (GWP) four times lower than previously calculated, below that of carbon dioxide.
The manufacturer says this new study confirms that its automobile air conditioning refrigerant — which came under scrutiny after Daimler said it burst into flames in some head-on collision tests — is “one of the world’s most environmentally friendly refrigerants.”
The independent, peer-reviewed paper, published in Reviews of Geophysics, is the first known study where the GWPs of all fluorocarbon-based refrigerants have been calculated consistently using all available atmospheric data, taking into account local atmospheric patterns, Honeywell says.
The study found mobile air conditioning HFO refrigerant R-1234yf, or HFO-1234yf, to have a GWP of less than 1. CO2 is considered the baseline with a GWP equal to 1.
Earlier studies had calculated the GWP for HFO-1234yf at 4, which is still a 99.7 percent improvement over the refrigerant most commonly used in the world’s automobiles, HFC-134a, also known as R134a, which is being phased out under the European Union Mobile Air Conditioning (MAC) Directive and will be banned in in the EU in 2017.
Ken Gayer, vice president and general manager of Honeywell Fluorine Products, says if applied to the European automobile fleet, HFO-1234yf could save 8 million tons of greenhouse gas emissions annually.
A study published last month by automotive engineering association SAE International concluded that HFO-1234yf was safe for use in cars. Fifteen global automakers, including General Motors, Ford and Toyota, all agreed with SAE’s conclusion that called Daimler’s testing that raised questions about the refrigerant’s flammability “unrealistic” and said it was 20,000 times more likely for a person to die in a plane crash than be exposed to a vehicle fire caused by a leak and ignition of HFO-1234yf.
Despite the studies, Mercedes automaker Daimler won’t use HFO-1234yf and continues to use the older refrigerant in its new Mercedes. France, citing greenhouse gas emissions concerns, has banned the latest models of Mercedes because they use HFC-134a.