The phase-out of several common commercial refrigerants is leading building owners to look for greener alternatives.
R22, one of several hydrofluorochlorocarbon (HCFC) refrigerants commonly used in commercial air conditioners, cold storage, chillers and retail food refrigeration, is likely to disappear from the market soon. Also on the chopping block are R134a, which is often used in refrigeration and light air conditioning, and R123, which has been used as a retrofit alternative in low-pressure centrifugal chillers.
The two-stage phase-out is governed by the Montreal Protocol, an international treaty that controls the elimination and use of ozone-depleting substances. The EPA was in charge of implementing the phase-out in the U.S. A 2019 lawsuit challenging the agency’s authority to de-list refrigerants paused the EPA’s ability to enforce the ban nationally. However, many states (especially ones that are members of the U.S. Climate Alliance, a bipartisan coalition of states committed to international climate initiatives) are establishing similar rules on a state level, explains Ivan Rydkin, engineer, refrigerant gases, for Daikin America. This action at the state level is driving many manufacturers to move forward with the phase-out anyway.
That means that the 34 HCFCs on the list – including R22, R134a and R123 – are still likely to disappear from the market soon.
Older refrigerants will still be available for a while even after manufacturers stop making them, and R134a chillers are legal for new purchase through Jan. 1, 2024, so you don’t have to rush out and stock up. But it may be worth the hassle to retrofit your equipment for newer refrigerants now, Rydkin says.
“If you have a much older system that has to be replaced within the next few years, the recommendation we give is to replace it now prior to any new regulations coming into force in 2022 and 2023,” Rydkin explains. “We really encourage building owners to be ahead of the regulation curve so they’re compliant today, and then those systems will stay in compliance for the near future.”
Here’s how you can make sure you’re using refrigerants that will stay compliant.
[Related: AHR Expo: What You Need to Know About HFC Refrigerants]
Understand Refrigerants and Global Warming Potential
The environmental impact of refrigerants is measured by two key indicators – ozone depletion potential (ODP) and global warming potential (GWP).
Ozone depletion potential refers to the amount of ozone depletion a substance can cause compared to a similar amount of CFC-11, the first widely used refrigerant. This chemical went out of production in the U.S. in 1996 and has an ODP of 1.
Global warming potential measures how much energy the emissions of a gas will trap over a given time period compared to carbon dioxide, which has a GWP of 1. In both cases, lower numbers indicate lower environmental impact.
“Ozone depletion potential refrigerants were replaced by some high-GWP refrigerants. At the time of development, we knew they were stable, but we didn’t know they had a global warming impact,” Rydkin explains. “Some gases, like R404A, have a global warming impact of up to 4,000, whereas R22 was around 1,800.”
High-GWP gases become dangerous to the environment when they leak. Some units, such as large commercial rooftop air conditioners or the refrigeration units in supermarkets, can lose 25-30% of their refrigerant charge every year, Rydkin says, ultimately emitting thousands of pounds of refrigerant gas into the air. The challenge to the market is to create a viable alternative that marries highly efficient heat transfer with low global warming potential and no ozone impact.
3 Low-GWP Refrigerants
Manufacturers have responded to the phase-out by developing workable new refrigerants and modernizing old ones. These options aren’t an exhaustive list – the EPA maintains a large database online broken down by end use and equipment type – but they represent some of today’s most popular refrigerant alternatives.
1. High-Pressure CO2
CO2 was one of the earliest commercial refrigerants, along with ammonia. It fell out of favor because it requires high pressure to serve as a refrigerant, which requires a high temperature for the compressor. The colorless, odorless gas is starting to make a comeback because the global warming potential is only 1 – leaks are only leaking CO2, not fluorocarbons.
The systems tend to have a higher first cost than other systems of similar size because of the complexity involved, but this may decrease if the technology gains wider acceptance. Stores like Aldi are beginning to embrace the technology as part of a larger effort to lower environmental impact. Some have even earned the EPA’s GreenChill certification, a designation recognizing food retailers who meet the agency’s criteria on refrigerant type, emissions and charge.
Supermarkets and other retailers are increasingly using standalone units, many of which use propane as the refrigerant, Rydkin says. “It has a global warming potential of 13, so that’s much lower than what was used before,” Rydkin adds. “Hydrocarbon standalone cases have shaken up the market in the last few years.”
3. R1234ze and R1234ze(Z)
Some of the new designs on the market for chillers and medium temperature refrigeration replace R134a (GWP of around 1,300) with R1234ze, which has a GWP closer to 1.
“The big impact is for large chillers that cool skyscrapers and hospitals. They’re moving to 123ze(Z) from either R123 or R134a,” Rydkin says. “There, they’re going from a mildly toxic option to a nontoxic, low-GWP option. In the large chiller space, there have been a lot of programs to get down to an environmental impact that we’re comfortable with while at the same time adding a tiny bit of efficiency gain.”
When and Why to Replace Refrigerants
Some systems allow you to replace your existing refrigerant with a new one as long as you make a few small changes, like changing the unit’s oil and adjusting some valves. Both are fairly common procedures in supermarkets that are upgrading refrigeration units, Rydkin explains. It’s much less common to retrofit different refrigerants into larger equipment, like chillers, because of the engineering obstacles involved.
California is proposing not allowing certain high GWP refrigerants for retrofits after 2022, Rydkin adds. It’s unclear whether other markets will adopt the same stringent requirements. When it comes to avoiding a big capital expenditure, Rydkin recommends being safe rather than sorry. “If you’re in a Climate Alliance state, do a retrofit now if you can,” he advises. “Otherwise, you’re going to be replacing the equipment later.”
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