As the cold chain industry moves toward sustainability and efficiency, hydrofluoroolefin (HFO) blend A2L refrigerants are emerging as the solution that balances environmental responsibility with operational excellence. Among these next-generation refrigerants, Solstice^® R-455A (L40X) is proving itself in real-world cold storage applications, offering facility operators a path to lower environmental impact without sacrificing performance, serviceability or profitability.

 

The Refrigeration Landscape

For cold storage facilities looking for a cost-effective option, HFO refrigerants offer global warming potential (GWP) savings of up to 99.9% compared to traditional HFCs and require minimum system/equipment redesign. A2L refrigerants are designed to mimic the refrigerants they are replacing by matching capacity and operating parameters, while reducing the engineering effort.

R-455A, with its GWP of 146, delivers across these requirements. Compare this to traditional HFC refrigerants like R-404A (GWP of 3,922) and R-507A (GWP of 3,985), and the environmental advantage becomes clear, it delivers a 96% reduction in GWP. Even compared to interim "bridge" refrigerants like R-448A (GWP of 1,386), R-455A offers an 89% improvement.

 

Why A2L Refrigerants Make Sense for Cold Storage

A2L refrigerants like R-455A offer compelling advantages. They provide similar operating pressures and temperatures to the refrigerants they replace, and they are engineered to balance capacity, efficiency, and temperature glide with low GWP. A2Ls can also offer lower total cost of ownership compared to alternatives, as they mimic legacy refrigerants within the HVAC industry for installation and performance.

The safety profile of A2L refrigerants also deserves attention. While classified as mildly flammable, A2Ls have a burning velocity of less than 10 cm/sec, making them approximately four times less likely to form flammable concentrations during an accidental leak than highly flammable A3 alternatives.

Under UL 60335-2-89 and ASHRAE 15, the maximum allowable refrigerant charge is determined by the refrigerant’s lower flammability limit (LFL), with the permissible charge increasing in direct proportion to the LFL. R-455A has an LFL approximately 11 times higher than propane and about 1.45 times that of R-454A and R-454C. Consequently, systems using R-455A can accommodate a higher refrigerant charge, enabling larger cooling capacity in cold room applications.

 

Real-World Success: Warehouse Facility with Dedicated Cold Storage

Theory becomes reality in a recent project constructed in the northwest, where a new cold storage facility demonstrates the practical benefits of Solstice^® L40X (R-455A) technology. Built to supply independent vendors regionally, this state-of-the-art facility serves vendors with refrigerated and frozen foods alongside non-refrigerated supplies.

The facility features walk-in boxes refrigerated by Bohn condensing units and evaporators utilizing L40X. The installation was designed to be easy to maintain, cost-effective, and fully compliant for years of efficient operation. The facility has now been in successful operation for a full year.

The cold storage facility installation adheres to ASHRAE 15 "Safety Standard for Refrigeration Systems" requirements. Calculations for refrigerant mass and minimum areas required for safety were performed, along with EDVC calculations per ASHRAE 15 standards. The systems were determined to be well below m₃ masses and easily met all regulatory limits.

The UL A2L certified Bohn evaporator units came equipped with on-board systems that control room temperature while providing integrated leak detection. When a leak is detected, the system automatically shuts off the supplied solenoid valve and runs fans to dilute any released refrigerant. A check valve on the suction line further limits any potential refrigerant release to only what's contained in the evaporator and the few feet of refrigerant lines inside the boxes.

 

A2L in Action

The system was charged with Solstice^® L40X (R-455A) and quickly reached operating temperatures. The superheat control of the electronic valves proved accurate, and the leak control system performed flawlessly during testing.

The new facility demonstrates that transitioning to A2L refrigerants is a strategic investment in efficiency, safety, and sustainability. L40X delivers the performance cold storage operators need and supports lower operating costs throughout the equipment lifecycle.

 

A Checklist to Consider for Your Next A2L Installation

A2L refrigerant and equipment may be new to field installations for cold storage, it is useful to have a comprehensive checklist for a safe and compliant installation. When planning your next project, consider the following key steps before beginning:

• Assemble a qualified team composed of the end user, contractor, OEM equipment supplier and project engineer
• Identify all required codes and reach out to the authorities having Jurisdiction (AHJ) early in the project
• Enlist available resources to educate and assist the team with questions and considerations
• Fully understand the differences relative to A1 installations and evaluate refrigerant containing piping and equipment. Run appropriate EDVC calculations and apply proper mitigations
• Specify and integrate a qualified refrigerant leak detection system
• Train all facility and service personnel on the nuances of the system

Although the rollout of A2L refrigeration equipment took a little longer than anticipated, it is widely available now, with major manufacturers offering commercial refrigeration systems. Given the market awareness on safe usage, reliability, performance and efficiency, A2Ls offer a cost-effective option that maintains a conventional system design while minimizing the GWP level—making them an attractive choice for cold storage.