By Joanna R. Turpin

LOW-TEMP EVAPORATOR: A technician from Optimal Air Solutions finishes installing a three-fan, KLP, low-profile, low-temperature evaporator from KeepRite. Courtesy of Optimal Air Solutions

The transition to mildly flammable (A2L), lower-GWP refrigerants is well underway, driven by the phasedown of high-GWP HFCs under the federal AIM Act. In commercial refrigeration, this means that new systems must use refrigerants that meet GWP limits of 150 or 300, depending on equipment type and/or size (compliance dates vary). 

The rollout of A2L refrigeration equipment took a little longer than anticipated, due to the need to finalize the necessary codes and safety standards. But all that work is done, and the first wave of A2L-compatible commercial refrigeration equipment is now available, with more introductions expected later this year. 

Refrigerant Choice 

Manufacturers had a variety of A2L options from which to choose for their commercial refrigeration equipment, but most settled on R‑454A (239 GWP), R‑454C (148 GWP), and/or R‑455A (146 GWP). All three can be used in systems with refrigerant charges under 200lb., which require a GWP below 300. For systems over 200lb., only R‑454C and R‑455A meet the stricter 150 GWP limit. 

Heatcraft Refrigeration Products is offering all three of these refrigerants in its new commercial refrigeration equipment, said David Bolanos, director of product management and marketing at Heatcraft Refrigeration Products.  

“These three A2L refrigerants, developed primarily for refrigeration applications, operate in both medium- and low-temperature applications and offer our customers a flexible choice of refrigerants for their needs.” 

A2L OFFERINGS: Heatcraft is offering the A2L refrigerants, R-454A, R-454C, and R-455A, in its new commercial refrigeration equipment. Courtesy of Heatcraft

He added that these three refrigerants have similar characteristics to their HFC counterparts with regard to performance.  

“The difference in refrigeration capacity depends on which HFC or HFO refrigeration system refrigerant it is being compared to, so it’s recommended that designers of refrigeration systems conduct due diligence to ensure proper selection and capacity matching, especially in replacement-type applications,” he said. “Users should always consult the refrigeration OEM’s published Technical Bulletins for capacity comparisons.” 

KeepRite Refrigeration’s A2L-compatible systems will also utilize R-454A, R-454C, or R-455A. When comparing these new refrigerants to the HFCs they replace, the company found that R-454A offered the best capacity and efficiency when compared to R-404A, said Vince Zolli PE, general manager and vice president of engineering at KeepRite Refrigeration. 

“It also performed similarly to R-448A, which is already recognized and accepted in the market,” he said. “R-454A demonstrated the best capacity and efficiency compared to R-454C and R-455A in laboratory testing; however, R-454C and R-455A will still be available for customers seeking options below 150 GWP.” 

Copeland also selected R-454A, R-454C, and R-455A for commercial refrigeration applications. According to Joe Summers, senior product manager, scroll and drives at Copeland, these three options have different capacities, performance characteristics, and GWP ratings, providing OEMs with the flexibility to meet refrigeration equipment requirements and comply with lower-GWP regulation targets. 

“At less than 150 GWP, R-454C offers minor capacity loss — only ~8% — compared to R-404A, while minimizing excess glide, which would require OEMs to implement major system redesigns,” said Summers. “R-454C has a similar glide to R-448A, which is used widely today; thus, it helps OEMs meet the 150 GWP threshold, maintain adequate capacity levels, and have the least impact on system redesigns.” 

For OEMs seeking to overcome the capacity loss of R-454C, stay below 150 GWP, and are willing to implement system design changes to support a higher glide level, Copeland is also approving R-455A. Summers noted that when compared to R-404A, R-455A offers higher capacity, but does come with ~22°F evaporator glide, which would require some system redesign, such as new coils. 

“R-454A offers similar glide as R-448A and an 8% to 10% capacity gain compared to R-404A,” he said. “However, its 238 GWP rating can only be used in applications that allow refrigerants less than 300 GWP, such as remote condensing units. However, in these applications, it provides exceptional performance and minimizes OEM engineering and system redesign efforts.” 

With a GWP of 150 or less required for certain types of equipment, the list of viable refrigerants narrows significantly — mostly to naturals or A2Ls, noted Adam Ciesielski, director of engineering at Zero Zone. “A2Ls, however, behave similarly to HFCs in terms of system performance. Their volumetric capacity for heat exchange is comparable, making them a practical alternative. We selected R-454C specifically for its lower glide compared to other low-GWP options.” 

Danfoss offers a full line of system components that are compatible with most A2L and A3 (R-290) refrigerants used across the HVAC market today, said Trenton Yule, application engineer at Danfoss. “Depending on the application, the refrigerant used in any system will change. Many of the OEMs that we work with in the comfort cooling space have elected R-454B as the replacement for R-410A. A few manufacturers have opted for R-32. We also have components that support the product cooling market, with the common A2L refrigerant being R-454A, R-454C, and R-455A.” 

New Options 

Commercial refrigeration manufacturers are rolling out a wide range of new equipment designed to accommodate A2L refrigerants. KeepRite Refrigeration, for example, has already launched its low-profile evaporators and remote condensing units with capacities ranging from .75 to 20 horsepower. Throughout the year, the company will introduce numerous additional A2L-compatible equipment, said Zolli. 

“By the end of the year, our goal is to have A2L-compatible options available across our entire product range, which includes evaporators, condensing units, multi-compressor units, condensers, coils, air handlers, heat reclaim, and parallel compressor systems,” he said. “Safety features on our A2L units include a refrigerant detection system (RDS) with leak sensors, a mitigation board/controller, and safety shut-off valves. If a leak is detected, the mitigation board will keep the evaporator fans running to circulate air throughout the room.” 

Danfoss has developed and/or requalified compressors, line components, microchannel heat exchangers, brazed plate heat exchangers, and sensors for use with A2Ls. Basically, everything offered for legacy A1 refrigerant systems needed to be adapted or developed to provide the same quality and performance with new A2Ls, said Yule. 

“One highlight is our A2L gas sensor. This new sensor was developed by Danfoss for compliance with UL60335-2-40 for air conditioning and UL60335-2-89 code requirements for gas detection systems in units utilizing A2L refrigerants,” said Yule. “This new code addition states a system sensor must be placed internal to a refrigeration unit and provide one fixed alarm setpoint at or lower than 25% of the lower flammability limit (LFL). The alarm setpoint varies depending on the specific A2L refrigerant.” 

Zero Zone is actively developing a full line of A2L-compatible refrigeration solutions across multiple product categories. This includes indoor and outdoor rack systems (up to 500 tons), single- and multi-compressor condensing units, and display cases, said Ciesielski. 

REFRIGERATION SOLUTIONS: Zero Zone is actively developing a full line of A2L-compatible refrigeration solutions across multiple product categories. Courtesy of Zero Zone

“To accommodate A2L refrigerants, Zero Zone has implemented several key design changes focused on safety and compliance. These include integrated leak detectors to identify refrigerant leaks early, safety shutoff valves, and the use of non-arcing or isolated components to minimize ignition risks,” he said. “Additionally, mitigation fans are incorporated into display cases to circulate air in the event of a leak, helping to prevent the accumulation of flammable refrigerant concentrations around the refrigeration system and its components.” 

According to Summers, Copeland is qualifying its entire product portfolio for use with A2L alternatives, from refrigeration scroll, semi-hermetic, and hermetic reciprocating compressor platforms and condensing units to valves, system electronics, controls, and VFDs. 

“Our E3 supervisory control platform, case controllers, and connected leak detection devices feature built-in A2L refrigeration system optimization logic to oversee safety management, such as shutting off the compressor and other components or activating safety shut-off valves,” he said. 

To qualify their scroll and semi-hermetic compressor platforms for use with R-455A, R-454C, and R-454A, Copeland implemented numerous design changes, including the following: 

• Hermetic housings that seal potential leak paths; 
• Reinforced electrical enclosures; 
• Spark-free terminals; and 
• UL 60335-2-40 and UL 60335-2-89 compliant EVM/EVH variable-speed drives that keep charge sizes and discharge temperatures tightly controlled. 

“In addition, our A2L-ready condensing units are all UL 60335-2-89 compliant and approved, assuring the proper design configuration for safety,” said Summers. 

Heatcraft Refrigeration Products offers a range of A2L-compatible equipment, including the Pro³ self-contained, packaged, refrigeration system, as well as A2L-ready versions of their core commercial product lines, which include all remote condensing units and unit coolers. 

“An exciting design element we introduced with these new A2L models, based on extensive input from our customers, is the capability to use the new A2L units with A1 legacy refrigerants,” said Bolanos. “Our A2L condensing units and unit coolers are UL listed for dual refrigerant class. That means our new A2L equipment can be used with A1 legacy HFC refrigerants, as well as the new A2L refrigerants for a flexible way to manage A1 to A2L conversions.” 

Heatcraft’s new A2L unit coolers offer a flexible pathway to A2L conversion to contractors and end users, said Bolanos. “Our customers have the choice to purchase a fully configured A2L system (i.e., remote condensing unit and unit cooler) with the RDS installed at the factory — this is great for new A2L applications or new room additions to existing facilities.” 

When replacing HFC equipment, Heatcraft offers the option to purchase the new A2L/A1 dual-class condensing unit or the new A2L/A1 convertible dual-class unit cooler. The A2L/A1 unit cooler, specifically, can be converted later with a field-installed RDS kit, said Bolanos.  

“It’s important to note that we are not upgrading existing A1-designed equipment. The conversion with the RDS kit occurs exclusively to our new A2L/A1 designed unit cooler and not to A1 HFC prior unit coolers with older designs.” 

With codes finalized and equipment now rolling out, the commercial refrigeration sector is fully stepping into the A2L era. Manufacturers are offering a wide range of solutions designed to meet current regulatory demands, as well as future-proof systems for years to come. 

Joanna Turpin is a Senior Editor at The ACHR NEWS. She can be contacted at 248-786-1707 or joannaturpin@achrnews.com. Joanna has been with BNP Media since 1991, first heading up the company’s technical book division before moving over to The ACHR NEWS, where she frequently writes about refrigerants and commercial refrigeration. She obtained her bachelor’s degree in English from the University of Washington and worked on her master’s degree in technical communication at Eastern Michigan University.