KARIYA – The debate over automotive heating, ventilation and air conditioning (HVAC) system refrigerants is expected to heat up in the next few years as European and American car makers find themselves going in opposite directions.

And again, the Japanese auto industry is caught in the middle.

At stake are tens of billions of dollars in revenues in North America and Europe, and many more billions in the emerging markets of China, India and Latin America.

“The U.S. and Europe are likely to go separate ways with CO2 (carbon dioxide) refrigerant,” says Junichiro Hara, a senior research official in the advanced engineering division of Calsonic Kansei Corp. “The U.S. will not accept it. Europe will probably adopt it.

“Japan and Asia will be dictated to by Toyota (Motor Corp.),” he adds. “Whatever Toyota decides, we will have to follow.”

What that means, says Masahiko Ito, general manager-air conditioning research and development at Denso Corp., “is that we must produce two different air conditioning systems in the future – CO2 for Europe and 134a for North America. (See related story: Auto Makers Applaud EU Proposal on AC Refrigerant)

“This is a big burden, not only for air conditioner suppliers but for the auto industry as a whole.”

For instance, Ito says, General Motors Corp. might have to stop exporting vehicles to Europe.

“Otherwise the company will have to find a CO2 air conditioner supplier,” he says. “At present, no one in the U.S. can make a CO2 air conditioner.”

Most manufacturers expect new EU regulations to go into effect in 2011, meaning CO2 air conditioner sales probably would begin in 2008 or 2009. Initial applications likely would involve vehicles in the $40,000-$50,000 range, including SUVs such as the Toyota Kluger V (sold in the U.S. as the Highlander).

“It will be difficult to adopt CO2 for small vehicles,” says Calsonic's Akihiro Tsurushima, general manager in charge of the company's mid-to-long-term product strategy group.

Several years ago, Denso announced plans to market a CO2 air conditioner on a conventional vehicle by 2007. The company subsequently delayed the timetable to 2008 or 2009.

Meanwhile, the supplier says there would be a 50% cost penalty at a yearly production rate of 100,000 units. At 1 million units, the company estimates a 10% cost penalty. Based on the current size of the market, demand should grow annually by 2 million to 3 million units depending on whether the EU decides to phase out R134a by 2015 or 2017.

To date, Denso's system has been commercialized only for Toyota's FCHV fuel-cell vehicle. A total of 16 of those vehicles are on the road. Calsonic Kansei claims to have sold three CO2 air conditioners to Nissan Motor Co. Ltd. for its XTrail FCV.

Zexel Valeo Climate Control Corp., Japan Climate Systems Corp. (a joint venture between Matsushita Electric Industrial Co., Mazda Motor Corp. and Visteon Corp.), and Mitsubishi Heavy Industries Climate Control Inc., Japan's third-, fourth- and fifth-largest HVAC system makers, have yet to commercialize CO2 units.

Unlike Denso and Calsonic, Zexel Valeo only is developing CO2 refrigerant for standard powertrain cars.

Regardless of the refrigerant, all manufacturers are committed to reducing size and weight of conventional HVAC systems. Size reduction “will be a major area of competition,” declares Denso's Ito. Within the next 10 years, engineers expect to make HVAC units 50% smaller and 30%-40% lighter. Ito notes that weight reduction varies by component. For instance, it should be possible to lighten the heat exchanger by 50%, but not the motors.

Using the HVAC system for the new Vitz subcompact as an example, size and weight will be trimmed to about 0.53 cu.-ft. (15 L) and 8.3 lbs. (3.8 kg), from 1.1 cu.-ft. (30 L) and 12.8 lbs. (5.8 kg) for the previous-generation Vitz unit.

Meanwhile, Calsonic hopes to cut system weight 10% over the next five years in line with Nissan's 8%-12% reduction targets. That means the HVAC system for a model such as the Teana, which weighs about 17.6 lbs. (8 kg), will be lowered to 15.9 lbs. (7.2 kg) when the next generation bows toward the end of the decade.

Zexel Valeo President Rikuo Miyake wants to reduce weight of its next-generation model (due out in 2008) by 10%-20%.

“In terms of size, we are already near the (minimum) limit,” he says.

Zexel Valeo's new B-segment unit weighs 16.3 lbs. (7.4 kg) and has volumetric dimensions of 1.2 cu.-ft. (35 L), 7% and 22% less, respectively, than the unit developed for Nissan's current-generation Wingroad.

Miyake says Zexel Valeo's main development goals are to improve air quality and comfort and to reduce weight, size and cost. The company's cost target is 30% below current levels, which it hopes to achieve by switching to lighter (and less costly) materials and components from emerging-market countries. He expects increasingly to outsource key components, such as blower motors and heater cores, from Southeast Asia and China.

Although Calsonic would like to make better use of space by reducing overall system size, the company's primary development goal is to reduce weight.

“While we strive to better utilize space inside the cabin, as well as to cut overall system cost, reducing the size of key components could have an adverse impact on performance,” Tsurushima says.