Chemical firms face the cold reality of refrigerant phase-out

Cooling-off period

11 June 2009 00:00  [Source: ICB]

With HFC refrigerants being phased out, the automotive sector is under pressure to find an alternative

THE EU'S ruling in 2006, that it would enforce a ban on the use of fluorinated chemicals, spelled out the end for hydro fluorocarbon (HFC) refrigerants in Europe's air conditioning systems.

The EU directive on emissions from automotive air conditioners means that new vehicles on sale in Europe must use refrigerants with a global warming potential (GWP) of less than 150. The industry-standard refrigerant R134a, used in cars manufactured in Europe since the 1990s, is not an ozone-depleting gas, but has a high GWP of 1,300. Carbon dioxide (CO₂) has a GWP of 1.

To put this into perspective, the Energy Information Administration (EIA), a division of the US Department of Energy, reports that vehicles in the US leaked 50,800 tons (51,613 tonnes) of R-134a into the atmosphere in 2005, the equivalent of more than 66m tons of CO₂.

Although the drive to come up with alternatives is well under way, the need to prove their viability has increased with urgency, with the closing of a legal loophole that would effectively have allowed car makers to continue using R134a-based systems in existing models until 2017. Following the tightening of regulations, the cut-off point for the transition to less environmentally-damaging gases in new vehicles will now be January 1, 2011.

COMPETING OPTIONS
There are two realistic contenders to replace R134a in automobiles, and both systems are at an advanced stage of development. The combined efforts of US chemical majors Honeywell and DuPont, and French chemical firm Arkema, have produced the fluorine-based HFO-1234yf.

In parallel, German automotive manufacturers' association, Verband der Automobilindustie (VDA), whose members include Audi, BMW, Daimler and Volkswagen, champions a system using highly compressed CO₂. Other European car companies, including Fiat, Renault and Peugeot-Citroen, have yet to commit.

Ray Will is a senior consultant at California, US-based chemical research institute SRI Consulting. Of the refrigerant options on the table, he says: "There's a level playing field, in that both systems can work, given certain parameters. Virtually all the companies that serve the mobile air conditioning market have products ready to roll."

Of the CO₂ option, Will says: "What's compelling about it is that nobody calls it a chemical. And when it comes to cost, CO₂ comes close to being free - no trademarks, so it cuts the chemical companies pretty much out of the business."

The news is not all good for CO₂, however. There's a question mark over its performance in particularly hot conditions. "Some smaller vehicles seem to have trouble getting cabin temperatures down quickly enough without causing more energy expenditure. So if you were trying to operate in southern Mediterranean countries or North Africa, there could be performance problems," says Will.

The fact that CO₂ systems contain the gas at extremely high pressure is another cause for concern. Will points to the outcome of an explosive release of gas, where a system could move, or even leave the car. There are also health implications of a fast rate of CO₂ release into the cabin.

"All in all, the safety aspects of CO₂ mostly deal with issues of release through high pressure," Will says.

Closer to being a drop-in replacement than its CO₂-based rival, the HFO-1234yf option is likely to deliver lower adoption costs, and the manufacturers claim considerable savings in fuel and greenhouse gas emissions over current systems. However, there are concerns over safety, particularly the chemical's flammability.

While tests continue, and manufacturers work towards a solution, Will has no doubt that it could be a real issue for potential end-customers. "The notion that you could have something coming out of the vents of your car, ignited, perhaps in concert with your airbag being deployed, would be a terrifying idea." Conclusive results of toxicity tests on HFO-1234yf are also still to come.

Claims and counter-claims abound on the safety, efficiency and cost-effectiveness of the rival approaches. Outside the VDA, the automotive industry is continuing to keep its options open. Inevitably, each system has its strengths and weaknesses.

Last year, to the discomfort of Honeywell, DuPont and Arkema, a German television news program aired film footage of crash tests purporting to show dangerous flammability and toxicity of HFO-1234yf. The tests were carried out by the Alliance for CO₂ Solutions, whose members include the German Environment Aid Association and international non-governmental organization Greenpeace. Honeywell says it is "puzzled" by the test results and has lodged a formal legal request for access for the test methodology.

While the European automotive sector plans for the beginning of 2011, the key date in the US is January 1, 2010. From then, under the Montreal Protocol, domestic and industrial air conditioning, and refrigeration system manufacturers will stop producing equipment that uses HCFC-22. There's an urgent need for alternatives here too. Based on the aggressive stepdown of HCFCs in the US, DuPont predicts that demand for R-22 will exceed allowed virgin supply by over 27m lbs (12,247 tonnes) in 2010.

Demand for R-22 remains strong thanks to a slower-than-anticipated transition to new equipment with alternatives such as R-410A. Although R-22 will continue to be produced for servicing and maintenance until 2020, DuPont and others in the sector are urging their customers to look at alternative new equipment, or, where possible, retrofit existing systems with sustainable refrigerant.

Because of R-22's use in both the refrigeration and air conditioning sectors, it is likely that more than one replacement will be needed to replace it entirely.

In refrigeration applications, R-404A and R-507A are being substituted for R-22. In air conditioning systems, R-410A - already in use in Europe - is the leading candidate. Although it is not suitable for retrofit and its higher operating pressures are incompatible with the design of R-22 systems. Retrofit options are available - R-407C or R-417A - at the cost of reduced performance.

As well as nervousness about potential shortages and subsequent price increases, the sector is aware of the need to be seen to be more "green" by environmental pressure groups. There is also uncertainty over the potential impact of the Environmental Protection Agency's intention to redistribute allocations for the production and import of HCFCs in 2009.

Although, as SRI's Ray Will puts it, "fluorocarbons are still alive and well", there are other refrigerants worthy of mention.

Hydrocarbons have been around for a while as an R-134a competitor in parts of the EU, boasting relative cheapness and a low direct GWP. The material's high level of flammability has meant it has fallen foul of building and fire codes in the US, and the need to eliminate ignition sources adds equipment costs.

While CO₂ was used in commercial applications in the past, before being replaced by CFCs, Will says he has not heard of any proposals to use it in single-room air conditioning, despite its apparent potential in the automotive sector.

Meanwhile, the jury is still out as to whether Europe's car manufacturers will go for CO₂ or the DuPont/Honeywell HFO1234-hy, or whether the two solutions may end up running in parallel. The implications for the automotive and chemical sectors, not only in the EU, but eventually in the US and the rest of the world, are considerable.

Will is watching with interest, but refuses to be drawn as to which option he thinks will prevail. "I don't want to be going into print saying one has an edge over the other. When one product is deemed to be the appropriate replacement it's going to be headline news."

Read Doris de Guzman's Green Chemicals blog