HVAC industry news
As mandated by the AIM Act, the U.S. is phasing down the use of high-GWP HFCs in air conditioning and commercial refrigeration equipment. In commercial refrigeration, this requires new systems to use refrigerants that meet the GWP limits of 150 or 300, depending on the size of the equipment. In response, the low-GWP alternative CO2 (R-744) has been gaining popularity in supermarket refrigeration systems, but some grocers have expressed concern over the complexity and expense of this equipment.
That is why mildly flammable (A2L) refrigerants should also be considered, according to Tom Mathews, vice president of sustainability at City Building Engineering Services (CBES) in Burlington, Massachusetts, and Kyle Klahre, PE, CEM, project engineer at Cuhaci Peterson in Jacksonville, Florida. The two men recently spoke about the benefits of A2Ls at the Food Marketing Institute’s (FMI’s) 2024 Energy & Store Development Conference in Baltimore, Maryland.
Why A2Ls?
Grocers have many reasons to consider A2Ls as part of their refrigerant transition strategy, said Klahre. These include their compliance with GWP regulation limits, as well as their reliability and ease of servicing, maintenance, and installation.
“Overall, they are utterly simple, conventional, and similar to what we are using today,” he said. “If we look at energy efficiency and cost effectiveness, A2Ls offer a unique strategy for this type of system. If we compare them to other A1-classified refrigerants, they’re actually performing either equal to or better from an annual energy usage standpoint. And this doesn’t matter what climate we are in, whether it’s in Miami, Denver, or Chicago. They are often ranking either at the top or in the middle with other A1 refrigerants.”
Klahre added that A2L refrigerants such as R-454C, R-455A, and R-1234ze also perform comparably to A1 refrigerants in terms of COP and glide, making them similar to what contractors and technicians are used to working with today. In addition, the system design is similar to traditional DX systems and includes compressors, condensers, TXVs, and coils, thus avoiding the complexities of high-pressure CO2 systems. A2Ls are also well-suited for remodels, he said, particularly in distributed systems or setups using secondary or cascade systems, where they can easily be integrated on the high side.
The difference between A1 and A2L refrigerants, of course, is that the latter are mildly flammable and as such, equipment utilizing these alternatives will require additional safety measures.
“ASHRAE Standard 15-2022 and UL Standard 60335-2-89 are both current safety standards we have to look at with A2L systems,” said Klahre. “The ASHRAE standard calls for various stop valves and leak detectors throughout the store, while UL 2-89 is about mitigation requirements for equipment, such as cases, coils, and racks, as well as maximum releasable charges.”