New Horizons for AC Refrigerants

This is the second half of a two-part post, beginning with Understanding AC Refrigerant Standards.

The race to find low-global warming refrigerants

Even so, the race is on to find alternatives to HFCs that have low GWPs and don't deplete the ozone layer. Chemical companies have zoomed in on three alternative refrigerants: ammonia, propane and, ironically enough, carbon dioxide (CO2).

All three have their limitations, Rajan Rajendra, director of Engineering Services at Emerson Climate Technologies, explained. “These three are not viable across the board in all applications,” he told 3p. “Some are expensive, ammonia is caustic, and propane is highly flammable.”

Another proposed alternative are HFOs (hydrofluoro-olefin) refrigerants, such as HFO-1234yf, which is being marketed and sold as a replacement for R134a in mobile air conditioning systems. Other HFOs, Rajendran continued, are “blends intended to create a refrigerant like R404A but with much lower GWP, and given a new mixture, one that can be used widely across all applications.”

Yet another alternative is one that has been around for a long time and has been used as an ingredient in the widely used R-410A. R-32 (difluoromethane) is a refrigerant industry participants have avoided to this point as it is mildly flammable, Rajendran explained, “but it has the advantage of having a GWP one-third that of R410A.”

Summing up the situation, “all the chemical companies have their own blends,” he continued. “So industry participants in Asian countries are being bombarded with all these different blends. Everyone is trying to figure out the best solution to transition away from R410A.”

Refrigerant standards: The current state of affairs

Outside of the Montreal Protocol, there are no regulations on the production and use of any HFCs in the U.S. “HFCs, like 404A, 410A and 134a, are legally viable in U.S.,” Rajendran told 3p. “At this point in time there doesn't appear to be any legislation on the horizon to ban these refrigerants in U.S."

(Note: a lower case “a” means the refrigerant is made up of a single type of molecule while an upper case “A” means the gas is a blend of molecules.)

Technology is keeping pace or is even slightly ahead of new refrigerant standards and regulations in the U.S., Rajendran believes. Regulation in Europe, on the other hand, is outpacing industry capabilities, which is causing confusion in the marketplace and industry.

Emerson, for its part, “is a co-supplier, along with chemical companies, to our customers,” Rajendran explained. “We aren't involved in the chemical production of refrigerants.”

When it comes to new refrigerants, Emerson is “agnostic, our only strong preference being that they are safe, energy efficient, as environmentally benign as possible, and economic. We have, or we will have products available that make sense in all of these aspects.”

To customers facing a choice of two or three alternative refrigerants, Emerson generally recommends they go for the one with the lowest GWP, other things being equal.

Regardless of the refrigerant used, Emerson also stresses the importance of energy efficiency and regular maintenance. Buying the most energy-efficient HVACR equipment and systems keeps refrigerant use down to a minimum, which results in cost savings over the long term. Similarly, keeping leaks down to an absolute minimum and keeping equipment finely tuned more than pays for itself over the course of the equipment and systems life cycle, he stated.

Green refrigerants and indirect emissions

Winding down, Rajendran raised another key aspect that should be central to any and all discussions and negotiations about new refrigerant standards: indirect emissions.

“People tend to forget, they may think that their equipment is green, but at the end of the day, that equipment is going to be in placed in your building or supermarket consuming energy minute after minute, day after day, year after year for 10 to 20 years.

“You have to think about the environmental impact beyond a conventional, one-dimensional approach. You have to consider the indirect emissions from electricity consumption and how that electricity is produced.”

Emerson is playing a key role in industry-wide initiatives that aim to identify and promote use of new refrigerants with zero in the way of ozone depletion potential and the lowest possible GWP. In the U.S., it is a leading member of the Air-Conditioning, Heating, and Refrigeration Institute's (AHRI) Low Global Warming Potential Alternative Refrigerants Evaluation Program (Low-GWP AREP).

Last November, AHRI released several final Low-GWP AREP test results, including those for residential heat pump, water-cooled chiller and commercial ice machine applications, along with refrigerant compositions.

“Eleven low-GWP refrigerants were tested, and their performance was compared to their respective baseline refrigerants, either R-410A or R-404A,” AHRI president and CEO Stephen Yurek was quoted in a press release. “This is the first set of many reports that will be published as part of our research program.”

AHRI tests are ongoing, with the complete set expected to be released publicly early this year after review and approval by the AHRI Low-GWP AREP technical committee. Stay tuned.