HFO-1234yf: A Global Alternative Refrigerant?

Nearly 15 years after R-134a replaced R-12 as the predominant refrigerant for mobile air conditioning systems, a leading candidate to be the next-generation refrigerant has emerged: HFO-1234yf.

Jointly developed by DuPont and Honeywell, 1234yf delivers similar performance to 134a, is compatible with 134a components and service equipment, and may potentially be used as a direct substitute.

“Tests show that 1234yf has 5% less cooling capacity in a drop-in state, but with some simple modifications we can optimize the system,” says Gary Hansen, Red Dot’s vice president of engineering. “We may need to fine-tune the TXV, or use XH7 desiccant instead of XH9, but these are minor changes compared to what other alternative refrigerants would require.”

Because 1234yf is a fluorocarbon blend, Hansen says, you should be able to use the diagnostic equipment, charging procedures, and service procedures you have now. In most cases, the only noticeable difference would be a distinct charge port.

For these reasons, it would appeal to on- and off-highway markets alike, he says.

The search for a global alternative to 134a has been driven by European legislation that would prohibit the use of fluorinated greenhouse gases with a global warming potential (GWP) greater than 150 for new vehicle models starting in 2011. 1234yf has a GWP of four; the GWP of 134a is 1,300.

Although no similar timetable exists in North America, global manufacturers of passenger cars, commercial vehicles, and other mobile equipment prefer one A/C system to address the world market.

“From our standpoint as a developer of heavy-duty and severe-service HVAC products, we want the best combination of performance, cost, and reliability for the people in demanding applications,” Hansen says. “Ideally, we’ll have one refrigerant that can be used all over the world for many different types of vehicles.”

Other alternative refrigerant options include R-152a and carbon dioxide. In July 2008, the U.S. Environmental Protection Agency ruled that 152a is an acceptable alternative to 134a in mobile A/C systems. The EPA deferred a ruling on CO2. “We know that CO2 isn’t a solution for our markets,” Hansen says.

Red Dot is one of the industry’s leading voices on alternative refrigerants for mobile HVAC systems. In 2007, Red Dot received the prestigious Climate Protection Award from the EPA for its work with refrigerants that reduce greenhouse gases.

“Refrigerant developers have a keen interest in Red Dot because we’re heavy-duty specialists and we’ve been working on alternatives to 134a for several years now. They want to make sure their refrigerants will stand up in harsh operating conditions and know we have experience that can help them.”