Jan. 1, 2020
Automotive technology never stands still, but it seems that every time we talk about air conditioning, the only thing to report is change. In recent years, mobile air conditioning has undergone some of the most dramatic changes in its 50-year history

This year's state of the industry report from MACS shows A/C changes are gaining more steam.

Automotive technology never stands still, but it seems that every time we talk about air conditioning, the only thing to report is change. In recent years, mobile air conditioning has undergone some of the most dramatic changes in its 50-year history, and there are still more to come. Some will be small, and some will make the switch from R-12 to R-134a seem like a walk in the park. And some recent changes actually might make your job easier and/or more profitable.

Looking at this history and where it's headed was a focus of one of the anticipated presentations at the annual Mobile Air Conditioning Society (MACS) Convention, as Ward Atkinson addressed attendees at this year's gathering. The exhaustive report that Atkinson, chairman of the Society of Automotive Engineers' (SAE) Interior Climate Control Technical Committee, presented covered a number of industry issues, including information on a recently completed study of existing A/C technology and how it will fit into the future.

That study and subsequently some of the more immediate changes are the result of work done by the Improved Mobile Air Conditioning (I-MAC) Cooperative Research Project. The two-year I-MAC Project began in 2005 with the goal of reducing "direct and indirect refrigerant emissions" from four different causes: system leakage, system efficiency, the car's cooling requirement and system service. In our part of the industry, the goal is to reduce the amount of refrigerant released during typical A/C service jobs by at least 50 percent.

The cooperative part of the I-MAC Project refers to the fact that it was managed by SAE, and the engineers working on it came from both the original equipment manufacturers (OEM) and the aftermarket (companies that make A/C parts and service equipment). Why was it necessary for car manufacturers to work with the aftermarket on service bay issues? There are two reasons.

Proving Their Case

The U.S. Environmental Protection Agency (EPA) has determined that based on the amount of refrigerant sold for service each year, roughly 20 percent of all R-134a refrigerant used in all vehicles is released into the atmosphere each year. About 40 percent of that amount is released from leaking A/C systems, and the remaining 60 percent is released during A/C service and scrapping of the vehicle. Surely the do-it-yourself (DIY) market is responsible for part of that 60 percent (some say a very large part), but the I-MAC Project made recommendations for improving refrigerant handling techniques and equipment for the pros that not only will reach the service industry goals, but also might save you money.

The first step is to make sure the pros have the right training and equipment. The pros are defined as people who get paid to work on mobile A/C systems, and this includes salvage yard workers, too. A training program was developed that focuses on preventing accidental release of refrigerant into the atmosphere through correct use of the recovery/recycle equipment, as well as proper refrigerant storage and container disposal procedures.

The one-day training course presents information that's genuinely useful to new techs and old hands alike, and completion of the course results in certification under Section 609 of the Clean Air Act. The EPA now requires anyone who gets paid to service the refrigerant circuit of a mobile A/C system, or recover refrigerant at a salvage yard, to have Section 609 Certification. (See sidebar " CERTIFICATION IN BATCHES.")

The EPA also requires A/C recovery/recycle (R&R) equipment to be certified to meet SAE performance standards. The I-MAC Project engineers took a fresh look at those standards and were surprised at what they learned. Even the best recovery equipment certified to the old SAE J2210 standard — and used properly — typically leaves 20 percent of the refrigerant charge in the system.

Some common work practices leave 30 percent. Industry estimates show that roughly 20 million to 25 million A/C systems are serviced annually, and roughly 30 percent to 40 percent of the vehicles arriving in salvage yards each year still have about one pound of refrigerant in the system. Even without doing the math, it's easy to see that improved recovery equipment and techniques are needed.

New performance specifications for R&R equipment were recommended by the I-MAC Project through the SAE. As of January, the EPA requires that all new R&R equipment must meet SAE standard J2788 (machines built under the old standard still can be sold until existing stock runs out).

The new standard requires recovery equipment to extract 95 percent of the refrigerant from the system in 30 minutes, and recharging equipment must have a charge accuracy of ± .5 ounce. The R&R equipment that meets these specs is more expensive, but in the long run these machines might actually save the pros some money. With more refrigerant being recovered before opening the system, less new refrigerant will be needed to recharge the system. With the improved charging accuracy, it should take less time to get the A/C system to perform properly. None of these advantages have been proven yet, but there's no doubt these new machines will reduce the amount of refrigerant released during service.

Protecting Our Technology

To meet strict new emissions regulations in Europe, a new type of A/C system has been developed in Germany that, at this point, seems likely to go into production for the 2011 model year. While it still relies on phase-change technology (turning high-pressure liquid to a relatively low-pressure gas), the refrigerant is R-744a, otherwise known as CO2. The high-side pressure in this system will reach 2,000 psi, so every component in this system will be radically different from anything on the road today. In addition, a slow leak of refrigerant into the cabin can impair the driver, so the ventilation system will be automated and far more complex. Building cars with this new A/C system will require a major redesign of many parts of the entire car. For instance, imagine what happens to a 2,000 psi accumulator in a collision.

In an effort to minimize those costly redesigns, the I-MAC Project has been investigating ways to improve existing technology to meet those tough new emissions regulations. So far, their success has been limited but promising.

Carmakers already are finding ways of reducing the amount of refrigerant needed to get the job done. One promising idea is called a secondary-loop system, which has a very small complete A/C system contained in a box under the hood. That small system cools a mixture of water and antifreeze that is circulated to a heat exchanger inside the cabin. In addition to using a much smaller refrigerant charge, the system also could be hermetically sealed, just like in a home refrigerator. This would eliminate the greatest single source of refrigerant leaks, the compressor seal. A sealed-system design is best suited to hybrid vehicles that have enough electrical power to run a compressor, but even a conventional secondary-loop system offers real advantages. Development continues.

Important Details

New SAE standards have already been established for improved compressor seals, less permeable hoses and tighter fittings. New compressors and entire A/C systems are being designed with fewer seals and joints, offering fewer opportunities to leak. Manufacturing techniques are being improved to hold tighter production tolerances. In lab testing, all of these small steps have already proven effective at reducing refrigerant leaks.

But the I-MAC Project already has concluded that meeting new European emissions standards will require replacing R-134a with some other refrigerant.

That's the bad news, because it means you'll eventually have to buy new R&R equipment and a new leak detector. Depending on what's chosen as the new refrigerant, you'll probably have to obtain new certifications, too.

The good news is that the average age of a vehicle in the U.S. is 9 years old and still climbing. You'll have R-134a vehicles in your service bays for quite a number of years, so any training and equipment you buy during the next year or two will still pay off.

Officially, the I-MAC Project funding has expired and its work is finished. Unofficially, some of the involved parties are still cooperating on certain issues, particularly on finding ways to avoid 2,000 psi system pressures. Field test results of R-744a systems are expected over the next year or so, and the next MACS Convention Report should finally have some solid answers.

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