Multi-refrigerant for Ultra-low GWP

A2L refrigerants offer cooling professionals a cost-effective option that maintains a conventional system design while significantly minimising the GWP level.

The release of the new Optyma™ condensing units and MTZ/ NTZ compressors—following the qualification of-valves and line components in 2020—means Danfoss has the widest portfolio of A2L-ready refrigeration solutions compatible with R1234yf, R454C and R455A refrigerants. With increasingly strict requirements to lower the Global Warming Potential (GWP) level of refrigeration systems, cooling professionals have an opportunity to start the green transition today by switching to A2L refrigerants with a GWP level below 150. And because change takes time, Danfoss will guide you through the refrigerant transition with frontline knowledge of growing requirements— and provide the products that are A2Lcompliant and safe to install. Non-toxic and mildly flammable, A2L refrigerants are gaining traction as a relatively easy way to further reduce global warming potential (GWP). With the cooling industry successfully phasing down the use of higher GWP refrigerants, countless applications are now benefiting from refrigerants that are kinder to the environment. Now, the next step is to go further and achieve ultra-low GWP. Natural refrigerants like R290 and CO2 are being used for a wide range of applications. But for installers looking for a cost-effective option that maintains a conventional system design, A2L refrigerants are excellent choices—offering a GWP saving of 90 percent and more.

The perks of being A2L-ready: preparing for the next high-GWP HFC phase-down

The transition to ultra-low GWP refrigerants is just on the horizon, with the next high-GWP HFC phase-down step coming at the end of 2021 with a 55 percent reduction versus the 2015 baseline. A2L refrigerants offer cooling professionals a cost-effective option that maintains a conventional system design while significantly minimising the GWP level. In practice, a refrigerant like R1234yf offers a 99 percent reduction in GWP compared with A1 refrigerant R134a—achieving that result without any added complexity. Our comprehensive range of A2Lready condensing units, compressors, and components ensures that we are prepared for the green transition when you are.

Optimised cooling for the future: the new Danfoss Optyma condensing units

The new Danfoss Optyma Slim Pack and Optyma Plus multi-refrigerant condensing units feature a future-proof design compatible with both A1 and A2L refrigerants—all in a single unit. You get the same highly serviceable units you know and love, designed to operate with A2L refrigerants safely and without complexity. “A2L refrigerants are environmentally friendly solutions that meet increasingly tough restrictions—but do require specific safety testing and design due to their mild flammability. The new Optyma condensing units have been ignition-proof tested in independent laboratories and designed with risk-mitigation precautions, such as a sealed electrical box, holes, and louvers to ensure the refrigerant’s dilution—giving installers peace of mind,”, says Rogerio Salhab Federici, Head of System Solutions at Danfoss Climate Solutions. Featuring a high energy-performance ratio, the updated Optyma condensing units enable you to gain higher energy efficiency while reducing energy consumption and indirect emissions. This powerful combination translates into an economically viable solution that you can implement today—backed by our complete portfolio of A2L-ready components.

Multi-refrigerant, A2L-ready compressors

Complementing the new condensing units, light commercial and commercial compressors are A2L-ready. The well-known MTZ and NTZ reciprocating compressors—for mid and low temperature applications respectively—are now qualified for use with R454C and R455A refrigerants and come in a low temperature setup. Plus, the scroll version will be A2Lready by Q3 2021—giving you a complete range of compressor solutions compatible with ultra-low GWP refrigerants.

Basic classification of A2L

Like ASHRAE standard 34, standard ISO 817 “Refrigerants —Designation and safety classification” provides an unambiguous system for assigning designations to refrigerants’ toxicity and flammability. In this case, A2L has lower flammability and toxicity compared to other classifications—making it the second safest refrigerant category. A=Non-toxic 2 = Flammable L = Low burning velocity BENB

Benefits of A2L Refrigerants

The primary benefit is on the GWP level. When compared to a popular refrigerant like R134a, an A2L refrigerant like the R1234yf offers up to 99 percent reduction in GWP. The very low or ultra-low GWP level makes A2Ls an attractive choice as regulations tighten further. As their physical properties are similar to HFC refrigerants, they’re also relatively easy to use and don’t add any system complexities Moreover, most of the tool installers are used to work with, can be used with A2Ls as well. Ultimately, being classed as “mildly flammable”, A2L refrigerants are a safe option for most refrigeration, air conditioning and heat pump applications since, they are difficult to ignite.

Working with A2L refrigerants—safety and risk mitigation

What does “mildly flammable” mean in practice? A2L refrigerants need at least 1,000 times more energy to ignite than most A3-class flammable refrigerants. It means that A2L refrigerants are unlikely to ignite from a discarded cigarette or a space heater. Even naked flames struggle to ignite A2L refrigerants under test conditions. What’s more, the “L” means they have a low burning velocity. So, even in the event of ignition, the flame will likely burn slowly and self-extinguish.

Factors that cause A2L refrigerant to ignite

For an A2L refrigerant to ignite, it needs to be highly concentrated. In practice, it would take a significant leak in an enclosed area to reach its lower flammability level of around 300g/m3. The refrigerant also needs to be exposed to an open flame or high-energy source. However, laboratory tests show that in most cases, even a blow torch flame struggles to ignite A2L refrigerants.

Are some A2L refrigerants more flammable than others

Yes, there are different lower flammability limits and ignition energies, but they all fall into the same class: A2L.

Lower flammability limit

Refrigerants need a certain concentration in air to generate a flammable mixture. The lowest flammable concentration is the lower flammability limit (LFL). For A2L refrigerants, the LFL is greater than 100g/m3; typically, it’s above 300g/m3. This means that for an A2L refrigerant to be flammable, its concentration needs to be ten times higher than for an A3 class refrigerant. With simple risk mitigation factors such as adequate ventilation in confined spaces, the chances of igniting an A2L refrigerant become very low.

Safety precautions to be taken

While the risks of ignition are low, it’s important to remember that A2L refrigerants are still mildly flammable—and subject to safety regulations. It’s critical to use properly qualified components. Danfoss Coolselector®2 is the quickest way of finding the right components for the right job. There are also some charge limitations to be aware of. Users can apply A2L refrigerants up to 11kg with basic safety measures according standard EN 378-2, and up to 54kg with increased safety measures like leak detection.