EPA presses for fast switch to A/C refrigerant R-1234yf

  • 07-Apr-2009 07:31 EDT

This refrigerant identifier from Neutronics has been modified to produce a "fingerprint" display from an R-1234yf sample. Shown is the readout for an R-1234yf sample of 95% or higher concentration.

If there were any doubt R-1234yf is on the fast track to be the next auto A/C refrigerant, it was dispelled at the U.S. EPA's R-1234yf Commercialization Meeting held recently in Dallas, TX, in conjunction with the Mobile Air Conditioning Society's (MACS) annual convention. The lead-off presentation—Road Map for R-1234yf Auto Air Conditioning with Federal, State, and Global Cooperation—was delivered by Dr. Stephen O. Andersen, EPA Director of Strategic Climate Projects. He made it clear that even though there is no current U.S. or state regulation, both EPA and CARB (the California Air Resources Board) want the industry to voluntarily beat or at least match the European Community's planned phase-out of R-134a. Having the session at the aftermarket-focused MACS convention gave EPA the chance to assess the service industry's readiness to make the switch.

Andersen said that the European Community's phase-out of R-134a starting in 2011 and concluding in 2017 is "slow" and that a more "rapid phase-out is certain in leadership markets. If EPA grants the California waiver related to greenhouse-gas emissions, as widely expected, it and a dozen other states [would wish to] implement quickly." His statement reinforced the position of CARB as the regulatory leader in this area.

CARB has said that it will accept four refrigerants as "environmentally superior choices." Minimally flammable R-1234yf and R-744 (carbon dioxide as a refrigerant) are the only active prospects. Three refrigerant producers, DuPont, Honeywell, and Arkema, have said they will make R-1234yf. Remaining available but with no front-line support are R-152a (a mildly flammable refrigerant) and AC-4 (a blend offered by Ineos Fluor, a European refrigerant producer).

Andersen said he expects Detroit automakers to "accelerate commercialization of R-1234yf to help satisfy green federal loan conditions." With the Obama administration looking to impose carbon trading, he said he foresees cap and trade prices for R-134a reaching $35/kg ($16/lb).

"It can be easy or hard," said Andersen in urging industry to lead on the matter of refrigerants, rather than letting government lead. "Take your pick, and [hopefully] pick industry leadership ahead of ... a patchwork of treaty, national, and local regulations ... and inconsistent standards."

The service industry reported specific progress on two fronts: equipment development; and a group of nine draft SAE International standards for equipment, components, and training by the Service Group of the SAE Interior Climate Control Committee (ICCC).

R-1234yf will be introduced with unique vehicle service valve fittings (and mating couplings for service equipment hoses) to reduce the possibility of incorrect charge and mixtures, as was done with R-134a. However, that did not prevent cross-contamination problems between R-12, R-134a, and other legal (and illegal) refrigerants, so refrigerant identifiers using infrared technology became important service testers. With a third OE refrigerant in the same pressure-temperature relationship range soon to come, the need for identification is even more important.

Peter Coll, Product Manager for automotive refrigerant identifiers at Neutronics Inc., said it would be possible to change software in identifiers made since 2004 to produce a "fingerprint" reading for R-1234yf. Once the refrigerant is in volume production, identifiers would be introduced that read out the exact percentage of the new refrigerant, plus percentages of other refrigerants and air in the system, Coll added.

Refrigerant identification will be especially important because safe, effective retrofit of R-134a systems to R-1234yf is deemed impractical. Even the retrofit of R-12 systems to R-134a, which was a comparatively simpler task, was not considered successful, said Ward Atkinson, ICCC Chair. Therefore, R-134a production would continue as needed to service the on-the-road fleet.

It may be possible to use electronic leak detectors certified to the new SAE J2791 standard. Basic tests confirm that the detectors will alarm on R-1234yf, although modifications to match their performance with R-134a may be necessary. A new SAE standard would be written to test for equivalent performance with R-1234yf.

The pressure-temperature relationship for R-1234yf is close to R-134a, but an 8% higher pressure develops if there is a 50-50 mixture in the system, such as from topping up an R-1234yf system with R-134a. If pressure gauge readings were relied on, they could lead to misdiagnosis and cross-contamination of refrigerant supply tanks. MACS President Elvis Hoffpauir said his organization would be working to develop service procedures and training for technicians to meet SAE J2845, which will cover the minimum content required for technician training to service R-1234yf, R-744, and R-152a systems.

EPA has advised the industry that like R-12 and R-134a, R-1234yf must be recovered and recycled, not vented to atmosphere. Although the basic recovery/recycle/recharge requirements for R-134a that are met by the SAE J2788 standard will apply to R-1234yf, a specific standard for R-1234yf equipment is being developed, designated SAE J2843. Manufacturers that participate in the ICCC’s Service Group have been testing proposed designs with no major issues reported, said Gary Murray, Engineering Manager, Tools & Equipment, SPX Corp.'s Robinair Brand.

The new equipment will require safety features to cover the R-1234yf flammability issue, including components that: have voltage and current limits; if exposed, will have a surface temperature limit of 405°C (761°F); and are non-arcing and/or arc-suppressed. In addition, the very small amounts of refrigerant that are vented in equipment operation (air purge, oil drain, and vacuum pump use) must be collected and directed into a garage venting system to outside air. SAE J2810, an R-134a recovery-only standard (for equipment typically used by salvage yards), is based in part on SAE J2788, and a similar one for R-1234yf, to be designated J2851, also is being developed. 

Although the members of VDA (the German auto manufacturers association) remain officially committed to R-744, all other carmakers have endorsed R-1234yf. No vehicle manufacturer has made a formal announcement for any specific refrigerant, and no plants to produce R-1234yf are near completion. The move to this refrigerant is expected to take off following the SAE Congress, according to attendees at the EPA event.

There still are many regulatory issues facing both R-1234yf and R-744 at the state level (Kansas, Texas, Utah, Washington, Louisiana, North Dakota, and Oklahoma are in various stages of changing laws). Further, EPA will not have a formal proposal to allow the four fluids as A/C refrigerants until late this year, so agency approval likely will not come until 2010. It will take simultaneous development at the automotive engineering level to be able to market any new A/C system, even in small numbers, any time in 2011, with 2012 more likely the earliest for any real volume. EPA approvals for R-1234yf, R-152a, and R-744 will require some safety mitigation to prevent dangerous passenger cabin concentrations — R1234yf and R-152a for flammability and R-744 for its effect on the motorist's respiratory function.

The minimal flammability of R-1234yf is expected to lead to labeling with A2L, a forthcoming classification from the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) and ISO (International Standards Organization). A2L, when officially in effect, will be a flammability level lower than the current A2 level at which R-152a is posted.

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