International. A2L refrigerants, classified as "slightly flammable", are characterized as viable alternatives to refrigerants with a high environmental impact.
Copeland has noted that A2Ls are in their early stages of adoption, as approvals and necessary updates to safety standards and building codes are still being defined.
A recent update to the safety standard under Underwriters Laboratories (UL 60335-2-89) has taken a key first step in its implementation for commercial refrigeration in the U.S.
Key challenges
A2L refrigerants have the potential to meet application challenges within the current and future commercial refrigeration landscape. They represent a potential alternative with increased cooling capacity in self-contained applications, with gas charge limits exceeding those approved for propane (R-290).
In addition, they also have a possible range of application in distributed architectures made up of condensing units for outdoor application or mini-racks, used in sales premises with a smaller format.
A2L refrigerants offer unique thermodynamic properties and, in some cases, similar or even better performance characteristics than those of more common A1 HFC refrigerants, such as R-404A, R-507, or R-134a.
A2L refrigerants are subject to specific charge limits, based on the lower flammability limit (LFL) of each refrigerant. These are among the first of many mitigation strategies when flammable refrigerants are used.
Based on the recent update to the second edition of UL Safety Standard 60335-2-89, A2L load limit guidelines have been established for self-contained and remote refrigeration systems.
For refrigerated displays, load limits are determined based on whether the equipment has an open design (no doors) or a closed design (with doors).
Safety and leak detection
A2L system architectures must be designed with specific safety and leak detection strategies in place to mitigate the possibility of flammability and ensure operational safety.
Installing remote systems with A2L refrigerants requires the use of mitigation measures to keep gas concentrations below flammability limits.
In addition to the E3 supervisory control platform, Copeland offers a complete set of leak detection valves and sensors for A2L refrigeration systems.
A2L refrigerants that meet the requirements
The company is currently qualifying its semi-hermetic compressor and Copeland Scroll lines to apply the main A2L refrigerant options.
"We have recently completed the construction of more than 90,000 square meters of research and development laboratories, with an extensive refrigerant testing capacity, with the purpose of innovating refrigeration technology, including the emerging A2L refrigerants," said the manufacturer.
Adoption
Copeland also indicated that HVAC-R technicians will soon encounter A2L refrigerants in new facilities and services. From a service standpoint, working with A2L fluids will require more rigorous attention to the basic fundamentals.
Recommended best practices for A1 refrigerants will be applied, with the addition of special safety considerations, in addition to new equipment and tools qualified for A2L refrigerants. The company has published a basic guide for technicians working with mildly flammable refrigerants.
