Cool Comfort

Because of European Union (EU) regulations that will take effect in 2011, German carmakers will substitute carbon dioxide for the fluorochemical they currently use to cool their vehicles. Fluorochemical makers are now racing to complete development of alternative coolants to prevent further erosion of the auto air conditioning business, one of their most important markets.

The automotive air conditioning market has been at risk for fluorochemical makers since mid-2006 when the 27 member states of the EU agreed to ban hydrofluorocarbon (HFC)-134a, used in virtually all car air conditioners today. The ban includes any fluorinated gas with a global warming potential (GWP) 150 times greater than an equivalent amount of CO₂. (GWP of CO₂ is 1.) The prohibition is part of the EU's effort, under the Kyoto protocol, to reduce the emission of gases that scientists believe contribute to global warming. HFC-134a has a GWP greater than 1,300.

Time is running out for fluorochemical refrigerant makers such as DuPont, Honeywell, Arkema, and Ineos, all of which are feverishly working to find an alternative refrigerant that beats the heat without warming up the atmosphere. At stake is a global automotive refrigerants market that stood at 135,000 metric tons in 2006, equivalent to about 17% of worldwide fluorinated refrigerant demand, according to market research firm Freedonia Group. The 2011 deadline is now three years away, about the same amount of time that automakers need to qualify a replacement refrigerant.

The best candidate the chemical industry has come up with so far is a hydrofluoroolefin with a GWP of about 4, jointly developed by DuPont and Honeywell. The two discussed the refrigerant, dubbed HFO-1234yf, in late November at the Second International Workshop on Mobile Air Conditioning held in Torino, Italy.

So far, the ban on HFC-134a has not spread beyond the EU. Because the U.S. didn't ratify the Kyoto protocol, automakers aren't under pressure to switch refrigerants for cars sold in the country. But automakers want a solution that works anywhere in the world they build and sell cars, as HFC-134a does today. And automakers can't adapt coolant systems designed for HFC-134a to work with CO₂ as the refrigerant; the systems must be entirely redesigned.

The Germans decided they can't wait any longer for a global solution. Beginning in 2011, members of the German Association of the Automotive Industry will replace HFC-134a with CO₂, known in the industry as R-744. Members of the association include Audi, BMW, Daimler, Porsche, and Volkswagen.

Other carmakers, including General Motors, are still on the fence and may yet adopt a suitable fluorochemical for cars sold in Europe. "We're keeping our options open as long as possible," says Fred Sciance, a manager in GM's Public Policy Center. But, he admits, "there will be some period of time when we're likely to use one system in Europe and another with HFC-134a in the rest of the world."

In the longer term, HFC-134a and other widely used fluorochemicals could be targets if government regulators enact tighter standards on greenhouse gases globally, but the EU regulations do not present an immediate threat to fluorochemical makers, says Chris Jellen, a Freedonia analyst. Europe accounts for 3% of the fluorochemical refrigerants used in cars, Jellen notes, and HFC-134a will be needed to recharge Europe's existing air conditioners for some time.

Mark S. Baunchalk, global strategic planning manager for DuPont Fluoroproducts, says his firm "is committed to developing low-GWP refrigerants for automotive and other applications."

HFC-134a is everything a carmaker could want, say both fluorochemical makers and their automotive customers. It is energy efficient, has low toxicity, and is not flammable. Ideally, both groups would like to repeat the experience they had when HFC-134a came out more than 15 years ago. Then, the auto industry replaced chlorofluorocarbon (CFC)-12 because it depleted Earth's protective ozone layer. HFC-134a was a virtual drop-in replacement for CFC-12 and didn't require manufacturers to extensively redesign air conditioning systems.

Global warming was not the concern back then that it is today. But now that it is, fluorochemical makers say they are working hard to come up with the best solution, and so far that's HFO-1234yf. About a year ago, DuPont developed an alternative refrigerant, code named DP-1, with a GWP of between 30 and 35. Honeywell developed another, named Fluid H, with a GWP of 4.

The two refrigerant makers joined forces last March and came up with a blend of the molecules in DP-1 and Fluid H. Their latest offering, HFO-1234yf, is a single molecule rather than a blend, Baunchalk says.

One attribute of the new molecule that's likely to get careful consideration is its flammability. While similar to HFC-134a in many ways, the new molecule is "mildly flammable," Baunchalk says. "We're working to minimize the flammability concern."

Alvaro de Ona, a spokesman for the Alliance for CO₂ Solutions, an environmental group, says the flammability issue shouldn't be minimized. He accuses Honeywell and DuPont of using HFO-1234yf to "slow things down and gain time" for fluorochemical refrigerants. De Ona sees a real virtue in putting to good use CO₂ that otherwise would be contributing to global warming.

David Diggs, Honeywell's global business director for refrigerants, says automakers are evaluating what they need to do to make sure flammability is not an issue. Both Honeywell and DuPont stress the energy efficiency of HFO-1234yf compared with CO₂, particularly in warm U.S. climates. They also stress its low GWP, its low toxicity, and the ease in adapting it to existing low-pressure systems. Both point to the high initial cost of designing, engineering, and manufacturing the high-pressure air conditioning systems required with CO₂.

Other fluorochemical makers are still hoping to develop the ideal alternative to HFC-134a. Ineos had planned a talk at the Torino meeting to discuss its best alternative but cancelled it at the last minute.

Joachim Merziger, European refrigerants director for Arkema, says his firm is making good progress in the development of a new fluorochemical refrigerant, but the firm is not ready to go public. Merziger still holds out hope that Arkema or its competitors will develop an acceptable alternative.

If CO₂ becomes the refrigerant of choice in Europe, traditional industrial gas suppliers would have no problem providing the gas in the purity required for auto air conditioners. It would be a very small business, compared with other uses for CO₂ such as beverage carbonation and fire extinguishers, says R. Glenn Fair, Air Liquide's standards technology and training manager.

Still, GM, the world's largest automaker, is not happy with the situation. "We have a problem with all the alternatives, including CO₂," Sciance says. Some automakers are hoping that Europe delays its 2011 ban on HFC-134a, but GM is "not actively" pursuing a delay, he adds.

Like many other automakers, GM is looking for a better answer for the cars it will be selling in Europe. Fluorochemical makers are hoping that when 2011 rolls around, GM and others will adopt a fluorochemical solution.