European auto, chemical industries seek next generation of refrigerants, as R-134a is phased out - corrected

Refrigerants heat up in Europe

11 February 2008 00:00  [Source: ICB]

A mandatory phase-out of the refrigerant R-134a in Europe has plunged fluorocarbon manufacturers into a high-stakes race to develop an alternative - corrects R-1234yf to HFO-1234yf, spelling of Baraba Minor, corrects chemical formulae and adds detail on Fluid H, DP-1 and AC-1

Clay Boswell/New York


THE SUMMER of 2007 may be remembered as a turning point in the fluorocarbon industry, for it was then that the members of the German Association of Automotive Industry (VDA), spurred by a European Union mandate, jointly decided to employ air conditioning systems using carbon dioxide (CO2), rather than a fluorocarbon, as the refrigerant.

If CO2 technology is adopted throughout Europe, manufacturers of fluorocarbon refrigerants will see the large mobile air conditioning (MAC) market significantly diminished.

Success in Europe could, in turn, drive adoption in the US, further shrinking the fluorocarbon market and transforming the economics of production.

Major players might consider consolidation, while newcomers in China, who have been aggressively adding new capacity, would see the value of their investments undermined.

The situation remains fluid, however. Despite setbacks, the fluorocarbon majors continue to pursue an alternative refrigerant that would at once minimize transition costs, perform as well as the current global standard - the fluorocarbon R-134a - and provide a life-cycle climate performance as good as or better than carbon dioxide. One promising entry, HFO-1234yf, was jointly debuted in late November by US majors DuPont and Honeywell.


It might sound odd, but CO2 has a relatively low global-warming potential (GWP) - just 1. R-134a has a GWP of 1300.

To help meet the EU's Kyoto Protocol obligations, the European Commission issued a directive in 2006 mandating the phase-out of R134a in mobile air conditioning (MAC) systems and its replacement by refrigerants with a GWP no higher than 150. As of 2011, a ban on R-134a systems applies to all new models, and as of 2017, to all cars.

European carmakers had two immediate choices, both requiring considerable redesign.

One was to use the fluorocarbon R-152a (CH3CHF2). R-152a has a GWP of 140 however, because it is flammable, it cannot be used in systems of the kind now found in cars. Instead, the AC unit must be equipped with an isolating secondary loop so that passengers are never endangered, meaning added weight and expense.

The other option was CO2 - also known as R-744. Several automotive suppliers have been developing CO2-based MAC systems and components, including Nippon Denso in Japan, ixetic and Behr in Germany, and Delphi and Visteon in the US.

CO2-based air conditioning systems are used industrially, but none has been installed in a car, partly owing to the engineering challenges posed by CO2. One of these is the high pressures required in the system, up to 10 times those of fluorocarbon-based systems. Another is the inefficiency of operating above a refrigerant's critical temperature, or transcritically - CO2 has a very low Tc of 31 degrees centigrade.

From the beginning, CO2 had an edge over R-152a, given the latter's flammability and bulky system requirements, and the situation did not look good for fluorocarbons.

Rather than watch the market disappear, however, Honeywell, DuPont and INEOS-Fluor all rushed to develop fluorocarbon alternatives to meet the new specification. The first efforts at a "global alternative refrigerant" were three blends named Fluid H, DP-1 and AC-1. They achieved varying degrees of success until last summer, when Fluid H was dropped over flammability and ozone depletion potential, while the other two failed to meet toxicity criteria.


Honeywell and DuPont teamed up in the aftermath of this disappointment to develop the next candidate, HFO-1234yf. It had originally been the major component of Honeywell's Fluid H, along with CF3I. Now the molecule, CF3CF=CH2, will bear the partner's hopes alone. So far, it seems to have performed well.

"Our goal has been to match R-134a as closely as possible," says Barbara Minor, engineering fellow at DuPont, "to minimize the transition costs and the work the OEMs [original equipment manufacturers] would have to go through to make the transition, but primarily to meet the GWP requirements."

HFO-1234yf made its public debut in late November at the 2nd European Workshop on Mobile Air Conditioning and Auxiliaries Conference in Turin, Italy. A study comparing the performance of HFO-1234yf with R-134a and R-744 (CO2) was also presented by the JAMA-JAPIA (Japan Automobile Manufacturers Association-Japan Auto Parts Industries Association) Consortium, says David Diggs, global business director of Honeywell's refrigerant business.

"The results showed that 1234yf has the lowest GWP impact regardless of region, and is a possible global solution that could even possibly replace HFC-134a in use in the existing legacy fleet," he says. "The results also concluded that because R-744 cannot adequately cool a car interior in warm and hot climates, it is not ideal as a global solution."

Diggs says the high pressures required by CO2 result in higher "indirect" greenhouse gas emissions (e.g., from the tailpipe) than HFO-1234yf.

Minor notes that CO2 systems must work harder to make up for the inefficiency of transcritical operation. She also questions whether the flexible connections necessary in a MAC system will be able to reliably maintain a seal under pressures so high. The need for redesign is another shortcoming. "There will be a very significant transition cost," she observes.

Proponents of CO2 MAC systems say these problems have been addressed indeed, they offer studies showing that CO2 MAC systems are actually more efficient than fluorocarbon MAC systems, even as fluorocarbon manufacturers point to studies demonstrating otherwise.

Either way, cars will be brought to market with CO2-based MAC systems. The first concrete move was revealed in December, when ixetic announced that a "renowned car manufacturer" had ordered systems for installation in a new model. In all likelihood, this is a German customer, and not the last.

Still, it may be possible to persuade the VDA to try HFO-1234yf, says DuPont's Minor. She notes that the organization is interested in the new refrigerant, having placed it on the agenda for the Alternative Refrigerants Winter Meeting, where she will make a presentation.

Her task may be difficult, however.

"My opinion is [the German manufacturers] are so busy trying to get something into production, you'd almost have to have something that was 101% ready for production to get something moving," surmises Ward Atkinson, chairman of the interior climate control standards committee of the Society of Automotive Engineers.

He considers CO2 systems, "for the moment, probably the mainstay for European manufacturers, [followed by] R-152a, and maybe HFO-1234yf somewhere down the line." There remain unresolved questions, he says, one of the largest being toxicity.


The results of two key toxicity tests will soon determine HFO-1234yf's fate, says Minor. "I think it's all going to be resolved at some point this year," she says. "The deadline is obviously looming."

If the material succeeds, it will offer automakers the option of remaining with a proven MAC system.

"CO2 is certainly not a mature technology," Atkinson remarks. "We're to the point now where cars last five to seven years before first service with R134a because we've learned about sealing techniques. What's going to happen with CO2?"

Whether European manufacturers would choose to remain with a proven system is another question.

"R-744 is the technical solution to a political problem in Europe," observes Ray Will, senior consultant at SRI Consulting, of Menlo Park, California. "In the US, we really aren't worried about Kyoto yet."

Indeed, the EC's original intention had been to mandate the adoption of CO2 MAC systems, says Atkinson. Only after the auto industry balked at the imposition did the EC allow for alternatives with a higher GWP. "If it's chemical, it has to be bad," he sums up wryly.

Will believes the ixetic deal shows that CO2 is on the verge of widespread adoption in Europe. "If they're successful, I think it's going to permeate the whole line," he says.

Subsequent migration to the US would be inevitable, he believes.

"I should hedge my bet whether we have R-134a in the future" Will adds, "but I think the most likely scenario is that when the Europeans hit their date in 2011, there might be a few bugs in the R-744 system, but the US will come around - maybe later than sooner - and we will end up with a world standard. Probably the last people on board will be the Chinese, because they have a big investment now in producing R-134a."

China has been taking advantage of its world-leading position in fluorspar, the mineral source of fluorine, to move up the fluorochemical value chain, says Will, vertically integrating through products such as R-134a. Large plants have been erected to produce R-134a in the expectation of fulfilling, at the very least, domestic demand.

"If the globe decides to change the standard, it pulls the rug out from under China's development plan," Will points out. "They're not going to be very accepting of this change."

In the West, fluorocarbon manufacturers pressed by the new conditions will respond in the only way that makes sense, he projects.

"Current events in the market make consolidation very likely," says Will. "We are looking at a very different dynamic here."

For Paul Hodges' Chemicals and the Economy blog, visit:

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