The matter appeared to be settled just two years ago. Automakers had agreed to use a new fluorine-based air-conditioning fluid in cars worldwide to reduce emissions of global-warming gases.
But now, because of safety concerns raised in September by Germany’s Daimler, carmakers worldwide are taking another look at the new coolant developed by DuPont and Honeywell International. Environmental groups, meanwhile, are renewing their call for automakers to use fluorine-free alternatives such as carbon dioxide.
“The industry already fought this battle, and the new fluorine refrigerant won,” contends Ray K. Will, a director with consulting firm IHS Chemical. Nevertheless, Daimler says it has conducted a “real life” test of the chemical makers’ new refrigerant, hydrofluoroolefin (HFO)-1234yf, that proves leaking gas could cause a fire in a head-on collision.
Daimler’s new test raises the question of how the company, maker of Mercedes-Benz automobiles, will meet the European Union’s January 2013 refrigerant deadline. It calls for automakers to use a coolant that has a global-warming potential (GWP) of at most 150 times that of an equivalent amount of carbon dioxide, whose GWP is 1. HFO-1234yf has a GWP of 4.
For now, Daimler wants to remain with the current refrigerant, hydrofluorocarbon (HFC)-134a, which has a GWP of 1,430, and will ask regulatory authorities to let it do so. It may later switch to CO2. Other automakers are set to use HFO-1234yf for now.
A spokesman for Antonio Tajani, the European Commissioner for Enterprise & Industry, tells C&EN that the commission has received no requests for waivers to continue using HFC-134a from any carmaker and that all firms must conform to the law in 2013.
Now that Daimler has raised its concerns, other carmakers find themselves between a rock and a hard place. “The safety of our customers is our highest priority,” says Curtis Vincent, air-conditioning engineering manager for General Motors. After Daimler’s release of the test results in late September, GM and others including Daimler, BMW, Ford, Honda, and Jaguar Land Rover convened a review panel under the aegis of SAE International, an automotive engineering organization.
Some automakers already have deployed HFO-1234yf. GM, for instance, is using it in the Chevrolet Malibu sold in Europe and the Cadillac XTS sold in the U.S. An SAE study group concluded in 2009 that HFO-1234yf could be safely used in cars. Vincent says he expects the new group will wrap up its review by the end of December.
Diane Iuliano Picho, a DuPont business manager, says she is puzzled by Daimler’s safety concerns. “Multiple risk assessments by industry stakeholders, including Daimler, have thoroughly evaluated the product’s flammability and have shown that there is no significant additional risk for HFO-1234yf versus the current refrigerant,” Picho says.
Ironically, she notes, the influential German Association of the Automotive Industry, known by its German initials VDA, endorsed HFO-1234yf in a presentation made at the European Automotive Air-Conditioning Convention in mid-September, just one week before Daimler raised the safety issue. Daimler is a member of VDA.
One slide in the VDA presentation points out that flammability of HFO-1234yf “does not lead to a higher level of risks for vehicle occupants or helpers at accidents such as firefighters,” compared with HFC-134a.
A Honeywell analysis concluded in November that Daimler’s test was not realistic. “Their tests are of an uncrashed vehicle without any of the dynamics involved in collision events,” the report said.
Terrence Hahn, vice president of Honeywell Fluorine Products, finds it odd that Daimler would question the safety of HFO-1234yf just 90 days before the European Union’s new mobile-air-conditioning rules go into effect. Automakers are experts at handling fluids such as gasoline and oil that are more flammable than HFO-1234yf, Hahn points out.
By raising safety questions, Daimler may be trying to avoid the cost of complying with European environmental regulations, Hahn suggests, noting that the German firm recently unveiled a $2.6 billion cost-savings program.
A Daimler spokesman tells C&EN that the company stands by its test scenario for HFO-1234yf. And far from saving money, the spokesman says, the decision to forgo using HFO-1234yf will probably cost more than going ahead with it. The firm has already spent money preparing to use HFO-1234yf. It might incur additional costs to eventually switch to a nonfluorinated alternative such as CO2, the spokesman says.
The German Environmental Aid Association says it is glad that Daimler is ready to toss aside HFO-1234yf. A spokesman for the environmental group says HFC-134a is also not the answer, “especially as an ecological and safe alternative has been around: It is called CO2.”
In fact, the German auto industry association endorsed CO2 as the auto refrigerant of choice in 2007. VDA quietly switched its allegiance to HFO-1234yf after global automakers, including VDA members such as Daimler, backed the fluorine-based refrigerant following SAE’s 2009 study of the gas’s safety.
VDA did not respond to C&EN’s inquiry about the group’s current position. However, press reports indicate that Volkswagen is also looking at CO2 as an alternative to HFO-1234yf.
“It is unbelievable that Daimler could extend the life of HFC-134a,” says Will, the IHS consultant. But even though Daimler may eventually adopt CO2, there is no stampede in favor of it. In mid-November, SAE invited automakers to form a committee to evaluate CO2 as an air-conditioning refrigerant. So far there are no takers.