R-454B: Pros, Cons, & Comparisons to R-410A

Our Refrigerant Focus series consists of deep dives into the history, properties, and pros and cons of some of today’s common refrigerants. This installment will focus on R-454B.

• Refrigerant Focus #1: R-32
• Refrigerant Focus #2: R-410A
• Refrigerant Focus #3: R-1234ze
• Refrigerant Focus #4: R-407A
• Refrigerant Focus #5: R-290
• Refrigerant Focus #6: R-744 (CO2)
• Refrigerant Focus #7: R-448A

History of R-454B as a Refrigerant

R-454B was developed in the late 2010s by Chemours and was formulated to serve as a lower GWP (global warming potential) alternative to R-410A, the usage of which has dominated the commercial HVAC market since the phaseout of R-22. R-454B, marketed by Chemours under the trade name Opteon XL41™, features a GWP of 466, significantly lower than that of R-410A, the GWP of which falls between 1890 and 2100.

Like with many of the refrigerants covered in our Refrigerant Focus series, environmental regulation is the driving force behind the development and adoption of newer refrigerants like R-454B. The AIM Act of 2020, which gave the United States EPA authority to regulate HFC substances, set the stage for the EPA to use that authority to impose incremental phasedown mandates for numerous HFC substances with GWPs over a certain threshold (700), with R-410A included among them.

EPA has imposed a deadline of January 1, 2025, after which the manufacture and import of many types of self-contained R-410A systems is prohibited. Consequently, unit manufacturers have been evaluating and deciding on a replacement since the phasedown’s announcement, with several of the largest domestic manufacturers settling on R-454B.

Other manufacturers – most notably Daikin – chose R-32, a nonblended refrigerant with a GWP of 675. We’ve included R-32 in the next section’s property comparison as an added data point to give additional context to the discussion around R-410A alternatives.

Properties of R-454B

Unlike R-410A, which is a near-azeotropic, two-part blend of equal parts R-32 and R-125, R-454B is a zeotropic blend of R-32 and R-1234yf. In azeotropic blends, constituent substances boil at similar or identical temperatures, but in zeotropic mixtures, those values differ, leading to glide, a term used to describe the temperature delta between the constituent substance with the lowest boiling point and the one with the highest. In the case of R-454B, that number is roughly 1.5˚ F, which, although not especially high, does have an impact on the complexity of calculating the refrigerant’s performance profile, a dynamic that was not a factor in R-410A performance modeling.

Pros & Cons of R-454B

R-454B: Pros

The most notable benefit of using R-454B is its compliance with the impending GWP limits we mentioned earlier. Also, from a performance standpoint, it features a similar coefficient of performance (COP) to its predecessor, R-410A, and can even be slightly better in some instances.

R-454B: Cons

The most notable drawback of R-454B relative to R-410A is the fact that it is a zeotropic blend, which, as we touched on earlier, adds a layer of complexity to the modeling of its performance profile.

Practical Implications of Property Differences Between R-410A & R-454B

While the difference in the COPs of R-410A and R-454B are negligible, the same can’t be said for their capacities. This means that while operating costs are largely similar, R-454B is not able to provide like-for-like thermal performance for the same operating costs as R-410A. For example, if an R-410A unit was designed to condition a space to 70F, an R-454B unit would need to use more electricity to meet that requirement.

This means that – in most cases – R-454B is not a direct drop-in replacement for R-410A. Only looking at COP may indicate otherwise, but capacity must also be considered.

Our test data indicates that R-454B coils will require 10 – 20% additional heat transfer surface to meet the same capacity as and R-410A design. This won’t necessarily be true for every application, and unit/system-level performance implications may be less stark than at the coil level. However, savvy OEM engineers will perform the due diligence needed to answer that question before deciding the extent to which unit designs must be adjusted.

If you’re an OEM and aren’t sure if your R-454B transition plan has accounted for COP and capacity, drop us a line. We’ll work with you to get a comprehensive answer to that question, so you – and your customers – can make the transition to R-454B with confidence and know that your units will meet their performance requirements.

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