SPECIALISTS IN AUTOMOTIVE COOLING SOLUTIONS
Replacement Refrigerants x Two
With a European phase out of current day automotive refrigerant, HFC-134a, scheduled to begin in 2011, the global auto industry has not decided on the next generation gas. The further for shop owners and technicians looks like a future of two gases - one for US, Asian and some European built vehicles and another for german makes.
Dr. Stephen Anderson, architect of the R-12 phase-out in the late 80's and now Director of Strategic Climate Projects at the U/S EPA hosted an industry meeting here at the 2009 convention of the Mobile Air Conditioning Society Worldwide (MACSW) earlier this year to discuss the commercialization of HFO-1234yf, one of the two leading contenders that will be used to as the next generation refrigerant to replace HFC-134a.
At the present, the auto industry is in the process to narrow its choices and two camps have emerged. The first can be characterized as the CO2 (known as its refrigerant designation as R-744) camp and it includes the German Association of the Automotive Industry (VDA) and some suppliers.
The second is the HFO-1234 yf camp (pronounced as twelve, thirty-four yf) that says in has the support of automakers that currently have 70% of the global auto market. In the middle and playing all sides are a number of engineering, tool, consulting and processing companies that are eager to work with either or both refrigerants.
The European Union has slated EFC-134a for elimination because it is on the schedule of green house gases. In addition to the protection of the planet from the global warming, the phase-out of EFC-134a puts millions of dollars for equipment, phases and parts on the table.
HFC-134a was developed as an alternative for R-12 in 1996. Now because HFC-134a is listed as damaging to the ozone layer and a contributor to global warming, it will be eliminated by law in new car production use by the European Union (EU0 beginning in 2011. The phase-in of the newer chemical will be gradual and tied to the introduction of new models.
In the past, the transportation OEM's and their suppliers cooperated and agreed upon a single refrigerant for obvious advantages in the reduction of cost and complexity.
Although all car-manufacturers are suffering the effects of global economic meltdown and a huge over-capacity problem, it does not look as if they are currently of the mind to reduce overall costs by cooperating on one single solution.
So at the present the global transportation industry wrestles with the very good possibility that there it will have to deal with two refrigerants. More problematic for the service sector is the fact that neither of them would be interchangeable with the other. The on-vehicle air conditioning systems in which each of the refrigerants would be used have different operating pressures and essentially function differently enough that HFO-1234yf could not be a drop in for R-744, with reverse as true as well.
What does this mean for a/c service? At the very least it will mean a realization that "one size fits all" may not be int eh picture. Equipment and tools and how to minamize their cost will be biggest problems to deal with. Will tool makers be clever enough to make things that swing both ways? Stay tuned. Although it won't be for awhile, it is time for shop owners and techs to put it on the radar.
As for the engineering community, they are already developing standards, equipment, tools and testing for both R-744 and HFO-123yf.
For a short recap - both R-744 and HFO-1234yf offer great advantages in environmental protection over the current R-134a, each has certain unique qualities and both face additional challenges.
R-744 or CO2 is said to be well suited for use in mild climates and has a very low Global Warming Potential (GWP) of 1. Critics of R-744 say there are several challenges facing the adoption of CO2 systems including a needed complete a/c system redesign, the need for higher operating pressures, cost and toxicity.
Additional concerns exist about fuel efficiency, and cooling for passengers cars.
According to information found at the SAE International website, the Global Warming Potential (GWP) is a measure of how much a given mass of greenhouse gas is estimated to contribute to global warming. The GWP is calculated as the ration that would result from the emissions ofone kilogram of a greenhouse gas to that from emissions of one kilogram of carbon dioxide over 100 years. The Global Warming Potential (GWP) is based on a relative scale with the unit for CO@ by definition as one.
HFO-1234yf is said to be a near dropin for direct, expansion mobile a/c systems. It is important to know that drop-ins are not part of the current plans. Its system operating pressures are similar to R-134a systems. However critics point out that HFO-1234yf is mildly flammable, is likely to have a higher refrigerant cost, and is not available in commercial quantities at the present. Although not as low as R-744, R1234yf does have a low Global Warming Potential (GWP) of 4.
With a deadline approaching and the future of refrigerant most uncertain, the transportation industry along with regulators, have been working to ease the transition by conducting research and developing standards for both R-744 and HFO-1234yf.
The Interior Climate Control Committee of SAE International has 16 new standards and two revisions currently in process. The standards cover: service equipment, recovery and charging, service hoses and fittings, leak detection equipment, trace dyes, technician training and certification, certified new and replacement evaporators, refrigerant purity, measurement of concentrations in passenger compartments, and system component design requirements.
Regardless of the choice of refrigerants, these standards will have an impact on the tools, procedures, parts, training and certifications required to service automotive air conditioning systems.
The technical community is preparing by hedging their bets by developing equipment, parts and standards for both HFO-1234yf and R-744 systems. There are five new standards for HFO-1234yf, four new documents common to HFO-1234yf and R-744, one revised standard for all refrigerants and six new documents for R-744.
The Cooling Journal - July 2009