Several developments in 2024 generated significant momentum for the commercial refrigeration industry’s transition to A2L refrigerant technology. Chief among these influences are the finalization of the U.S. EPA’s Significant New Alternatives Policy (SNAP) Rule 26 and the industry’s preparation for hydrofluorocarbon (HFC) use limitations implemented under the American Innovation and Manufacturing (AIM) Act’s Technology Transitions Program. As AIM Act schedules work to achieve a total 85% HFC phasedown from historic baseline levels by 2036, SNAP Rule 26 and the Technology Transitions Program complement each other to bring A2L refrigerant innovations to the doorstep of businesses along the commercial refrigeration cold chain that are looking for alternatives to HFCs with high-global warming potential (GWP).

SNAP Rule 26 and Technology Transition

SNAP was established 30 years ago under Section 612 of the Clean Air Act, which requires the EPA to identify and evaluate substitutes for end uses that historically have utilized ozone-depleting substances. The EPA evaluates a substance’s overall risk to human health and the environment, based on criteria such as ozone depletion potential (ODP), GWP, flammability and toxicity; occupational and consumer health and safety; and environmental risks, including impact on ecosystems and local air quality. SNAP approvals provide guidance for solutions that help establish a foundation for industrywide use of new-generation refrigerants that support environmental necessities such as reduced energy consumption and lower GWP.

Under SNAP Rule 26 (Protection of Stratospheric Ozone: Listing of Substitutes Under the SNAP Program in Commercial and Industrial Refrigeration), the EPA deems 10 refrigerants as acceptable, subject to use conditions, for various commercial refrigeration applications, including industrial process refrigeration, cold storage warehouses and retail food refrigeration.  Six of these refrigerants have a GWP under 150: R-1234yf, R-1234ze(E), R-454C, R-455A, R-457A, and R-516A. A few refrigerants with a GWP greater than 150 — R-454A, R-454B and R-32, for example — are also listed as acceptable substitutes because their performance characteristics necessitate their use in certain applications.

Technology Transitions Program rules, or “sector controls,” limit use of HFCs and support A2L adoption by calling for GWP limits for refrigerants based on specific applications. Some rules started to impact the industry on January 1, addressing such applications as vending machines, retail food refrigeration stand-alone units, and refrigerated transport. The EPA’s Technology Transitions Program Fact Sheet offers additional information.

It is relatively simple to see how SNAP Rule 26 and the Technology Transitions Program align. SNAP Rule 26 lists substitutes that meet the requirements of sector-based GWP limits in commercial refrigeration and other applications specified under Technology Transition rules. The approval of several A2Ls as acceptable substitutes, has opened the door for refrigerant manufacturers to commercialize high-performing A2Ls with significantly lower GWP—specifically, R-454A and R-454C. In addition, OEMs now have the green light to use these new-generation refrigerants in new commercial refrigeration systems.

Differences and Similarities

Discussions comparing legacy refrigerants and new-generation A2Ls lean into environmental properties. As regional, national and global environmental strategies advance, it will be increasingly important to consider which refrigerant options support those strategies. Such factors include how well refrigerants support decarbonization, circularity, energy efficiency and reduced energy consumption.

HFCs and A2Ls have zero ODP, and both can be recovered, recycled and reclaimed. But a significant differentiator is GWP. Two emerging A2Ls in commercial refrigeration, R-454A and R-454C, have GWPs of 239 and 148, respectively. In comparison, R-404A has a GWP of 3,920. R-1234yf, a key component of many refrigerant blends and also listed as acceptable under SNAP Rule 26, has a GWP of 4 (AR4). In terms of performance, A2Ls offer similar operating pressures and temperatures to the refrigerants they are designed to replace. When compared with alternatives, A2Ls:

• Are engineered to balance key refrigerant properties — such as capacity, efficiency, and temperature glide — with GWP.
• Offer lower total cost of ownership (accounting for capital and operating costs) than CO2, especially in warmer ambient climates.
• Have lower toxicity and a more advantageous safety profile than ammonia and hydrocarbon refrigerants.
• Support efficiency of space in refrigeration facilities, with most equipment globally designed specifically for modulated systems and engineered to deliver refrigeration where necessary, without long line sets.

The final notable difference is that A2Ls, named for their ASHRAE safety classification, are mildly flammable, have low toxicity and are for use in new equipment only. This mild flammability in part allows A2Ls to achieve lower GWP while optimizing refrigerant performance. Compared with A3s (hydrocarbons), A2Ls have lower burning velocities. They are also less likely to form flammable concentrations in the event of a leak and are significantly harder to ignite. A2L equipment and tools are designed to support safe use. For example, many systems are required to have leak detection and mitigation technology, and A2L cylinders have opposite-side threading to serve as a reminder not to accidentally charge an A2L refrigerant into a system designed for A1s.

Options for Commercial Refrigeration

Currently, two new-generation A2L refrigerants are gaining traction for a variety of commercial refrigeration applications: R-454A and R-454C. R-454A—developed to replace legacy refrigerants such as R-404A. It is suitable for low- and medium-temperature commercial refrigeration applications. Systems with charge limits up to 200 lbs.—such as remote condensing units for food retail walk-ins—are ideal for R-454A. Offering a GWP under 300, this refrigerant was specifically designed to achieve better capacity and efficiency than R-404A. R-454C—suitable for new systems in applications requiring a GWP of <150. Two examples are small standalone units and larger system architectures with a charge size of >200 pounds. This refrigerant was designed to improve upon R-404A by optimizing capacity, temperature glide and efficiency, while still maintaining a GWP of less than 150.

When determining your A2L transition strategy, keep in mind:

• Climate: Where ambient temperatures exceed approximately 75 degrees Fahrenheit, CO2 systems become inefficient and more costly to operate than A2L systems.
• Current equipment condition: Depending on where a current system is in its lifecycle, it may be more strategic to invest in A2L equipment instead of incurring costs for ongoing repairs or a retrofit.
• Energy management strategies: A2L systems can replace old commercial refrigeration systems, improving energy efficiency and reducing environmental impact.
• Corporate decarbonization goals: As mentioned above, A2Ls support energy efficiency and reduction in GWP.

Lastly, consider situations where A2Ls may not be advantageous over other options. Hydrocarbons may offer efficiency benefits in very small applications, like home refrigerators. The “sweet spot” for A2L use in commercial refrigeration falls between systems requiring more charge size than a hydrocarbon would allow for and systems where the applied cost of CO2 (equipment plus operation) is too high.

Although a newcomer in commercial refrigeration, A2Ls have been used effectively and safely for approximately a decade. R-1234yf, a component in many A2L blends, charges air conditioners in approximately 90% of vehicles sold in the U.S. Plus, the industry is seeing successful A2L installations from early adopters. Cases include Hensley Beverage Company, which installed a system using R-454C, and a milestone cold storage refrigeration system using R-454C in a region with one of the hottest ambient climates in the U.S. These examples can instill confidence as commercial refrigeration users and businesses strategize for A2L transition. 

A2Ls are approved for use in many commercial refrigeration applications. This approval broadens the equipment options available and facilitates the strategic collaboration between refrigerant producers and equipment manufacturers to ensure a robust and expansive supply chain—clearing A2Ls for takeoff. For facility managers, store owners, and other decision-makers, the time is right to start considering strategies for replacing equipment with systems offering the lower GWP, greater energy efficiency, higher performance, and other benefits associated with A2L refrigerants.