A respected refrigeration pioneer believes that HFCs are on shaky ground as long-term refrigerants and called for more focus on such “natural” refrigerants as CO2and halocarbons.

“I hope that some of the refrigerants currently in use will continue as refrigerants — but I’m not holding my breath,” said S. Forbes Pearson, president and CEO of Star Refrigeration in the United Kingdom.

His address keynoted a gathering of hundreds of researchers and engineers from throughout the world at the 21st International Congress of Refrigeration held recently in Washington.

Pearson asserted that the HVACR industry’s record with such “synthetic” refrigerants as CFCs, HCFCs, and HFCs “is not good.” In noting that CFCs and HCFCs are already being phased out, he said HFCs are being questioned as well.

“Atmospheric concentrations of (R-)134a are rising exponentially because of automotive air conditioning (leaks), and supermarkets (which use HFCs 404A and 507) have experienced refrigerant losses of 30 percent annually.” Environmentalists and some governments are now targeting HFCs because of perceived global warming issues.

Pearson said better containment could temper critics, but the only really leak-tight systems are those that are factory-sealed and therefore cannot be opened for servicing, such as window air conditioners and domestic refrigerators.

He said his focus on CO2 came about because it is a natural refrigerant with no ozone depletion potential or global warming potential. He said, “CO2 as a refrigerant by itself can be ruled out because of low efficiency associated with low critical temperature. But it can be efficient in cascade systems along with another refrigerant such as ammonia.”

Ironically, he partially blamed the current learning curve regarding CO2 systems on the industry’s shift toward CFCs in the 1930s. He said CO2 was starting to gain favor when CFCs became the industry standard.

“CO2 would have been developed more quickly 50 years ago.”

He said one current problem in getting CO2 interest restarted is lack of components. “We can’t buy a compressor that will pump high enough pressure to allow for hot gas defrost.” For a CO2/ammonia system his company was involved in, that problem was overcome with the addition of a positive displacement pump.

His advocacy of halocarbons had some considerations. “If there is a long term for halocarbons, it is restricted to factory-sealed systems (because of safety issues).” But he sees potential for such sealed systems as part of a secondary loop or distributed technology. In such cases he said research would be needed to improve efficiencies.

“We are in a time of transition in refrigeration,” he told the audience. “Such times are always interesting, painful, and dangerous. This is a time of challenge and opportunity.”

Pearson’s prediction concerning the future of HFCs was not necessarily shared by others at the conference. In fact, among the presenters of some 34 papers specifically related to CO2, many saw HFCs as remaining viable in the long term. They advocated CO2 being considered as an option along with other natural refrigerants as well as HFCs.

Still others said that while HFCs could well be heading for phaseout in Europe, that may not be the case in the United States. One speaker referred to the situation as the “Atlantic Divide.”