Navigating the New Refrigerant Landscape
How the global HFC phase-down is impacting commercial refrigeration.
The commercial refrigeration industry is undergoing a massive transition in the types of refrigerants that can be used across a wide range of applications. At the heart of this shift is an environmental initiative to limit the use of hydrofluorocarbon (HFC) refrigerants with high global warming potential (GWP) and replace them with lower-GWP synthetic and natural alternatives. In the U.S., the Environmental Protection Agency (EPA) has spearheaded this effort through its Significant New Alternatives Policy (SNAP), which set forth an HFC “change of status” schedule in its landmark ruling in July 20151.
This regulation created a ripple effect throughout the commercial refrigeration industry, mainly because the refrigerants identified for a status change from “acceptable” to “not acceptable” were among the most commonly used, including: R-404A/507A, R-410A, R-407A/C/F and HFC-134a. Among these, R-404A/507A has the highest GWP of 3,922. These HFCs comprise the complete spectrum of commercial refrigeration applications, from supermarket racks, remote condensing units and walk-ins to low- and medium-temperature, standalone units. In other words, virtually every refrigeration application will be impacted by this ruling, sometime between January 2017 and January 2020.
In September 2016, the EPA finalized a second ruling2 that broadened the HFC change of status into additional commercial refrigeration and air conditioning applications. With these new applications now included, the HFC impact schedule was extended into the 2024 time frame.
Updates to Safety Standards Underway
To help ensure the safe use of A2L and A3 refrigerants, national and international governing bodies are currently evaluating safety standards and charge limits5. These efforts include:
Review A2L safety standards:
- U.S.: UL 1995, ASHRAE 15; target date is late 2017
- International: ISO 5149, IEC 60335, EN378; target date is late 2017
Update building codes:
- Building codes for mildly flammable (A2L) refrigerants are being expedited for adoption in the 2021 code cycle
Evaluate A3 charge limits:
- U.S.: raising the A3 charge limit from 150g to 300g–500g
Flammable refrigerant study
- $5.2M partnership by AHRI, ASHRAE and DOE to study flammable refrigerant behavior in real-world applications
But this HFC initiative extends well beyond U.S. borders. In May 2014, the European Union’s F-Gas regulation went into effect, calling for refrigerant GWP reductions down to 150 in self-contained and centralized refrigeration applications by 2022. Environmental Canada (EC) has developed its own F-Gas proposal that also calls for significant reductions3.
And, in October 2016, the Kigali Amendment to the Montreal Protocol4 — an international treaty that was originally formed in 1987 to protect the stratospheric ozone layer from damage caused by chlorofluorocarbon (CFC) refrigerants — formed a consensus among 197 countries to progressively phase down HFC refrigerants over 30 years. This amendment, which has yet to be approved or implemented, provides a degree of certainty that this global effort will continue for the foreseeable future.
What’s the Alternative?
So, as many of the industry’s common refrigerants are targeted, the question on everyone’s mind is, “Which new refrigerants will replace them?” As part of its SNAP rulings, the EPA has also put forth a list of refrigerant alternatives. Since the 2015 ruling, the agency has published subsequent updates that deem certain new and natural refrigerants as “acceptable for use, subject to use conditions” in specific applications. Many chemical manufacturers are currently working with the EPA to get their new synthetic refrigerant blends placed on this list of emerging alternatives.
Outside of GWP considerations, refrigerants are typically evaluated by their operating performance (pressure or capacity) and safety classification as defined by the American Society of Refrigeration, Heating and Air-Conditioning Engineers (ASHRAE). To govern the safe use of refrigerants, ASHRAE has designated safety classifications that denote varying degrees of toxicity and flammability. Refrigerants used in commercial refrigeration generally fall into the following four categories:
- A1: lower toxicity; no flame propagation
- A2L: lower toxicity; lower flammability
- A3: lower toxicity; higher flammability
- B2L: higher toxicity, lower flammability
Many of the refrigerants targeted for phase-down are classified as A1 refrigerants, and were widely adopted due to their performance characteristics. But, in light of the current regulatory climate, the environmental qualities of these refrigerants were deemed unacceptable. However, to limit the amount of changes to refrigeration equipment and system architectures, their performance characteristics are used as a baseline for the development of a new class of lower-GWP alternatives. In fact, some new synthetic refrigerants are even designed to be “near drop-ins” to their higher-GWP counterparts, requiring minimal equipment and application design changes.
Leading chemical manufacturers have answered the call for alternative A1 refrigerants, starting with the development of a series of lower-GWP synthetic blends (HFC/HFO) that the EPA has already listed as acceptable for use. R-448A/449A and R-449B are among the “R-404A like” (medium-pressure) options, while R-513A and R-450A are “HFC-134a like” (low-pressure) substitutes. These all have relatively lower GWPs than their HFC counterparts, ranging from 350 to 1,300.
These manufacturers also have several “future proof,” very low-GWP options (<150) currently undergoing the EPA’s SNAP approval process. However, to achieve these extremely low GWP levels, these HFO blends all fall under the A2L (mildly flammable) classification. As such, studies are currently underway by the governing bodies to develop safety use standards for this emerging class of refrigerants (see Safety Standards side bar.) Among the medium-pressure alternatives include R-455A, R-454C and R-457A, while HFO-1234yf/ze and ARM-42 comprise the low-pressure refrigerant options. As these compounds navigate the EPA approval process, look for future SNAP ruling updates to verify their specific use parameters.
Aside from these synthetic blends, there are also a few high-performance natural refrigerant alternatives that are not only very low-GWP options, but acceptable for use per the EPA’s SNAP ruling. Ammonia (NH3 or refrigerant name R-717), propane (refrigerant name R-290) and carbon dioxide (CO2 or refrigerant name R-744) are all refrigerants that occur naturally in the environment and have a long history of use in refrigeration applications.
Ammonia has excellent thermodynamic properties and was among the first refrigerants used in refrigeration applications. As a B2L refrigerant, R-717 use requires careful adherence to safe application procedures. Ammonia’s suitability in low-temperature applications has made it a mainstay in industrial, process cooling, cold storage and ice rink applications. Today, some environmentally conscious supermarkets are trialing all-natural NH3/CO2 cascade systems to significantly reduce their carbon footprints.
Propane is a hydrocarbon that was also identified in the early days of refrigeration as a high-capacity, energy-efficient refrigerant with superior performance characteristics. The advent of synthetic A1 refrigerants moved the industry away from R-290. But since the 2000s, R-290 has been regaining global popularity as a lower-GWP, effective alternative to HFCs such as R-404A and HFC-134a. R-290 applications typically have a charge limit of 150 grams, making it especially well-suited for a wide range of low-charge, reach-in display cases. Regulatory bodies that govern refrigerant safety standards are currently evaluating expanding its charge limits.
CO2 is a non-flammable and non-toxic refrigerant that has proved a very effective alternative in both low- and medium-temperature applications, especially in regions with lower ambient temperatures. Its low critical point and high operating pressure (around 1,500 psig or 103 bar) dictate that CO2 refrigeration strategies must be designed to account for these unique characteristics. CO2 cascade, secondary and transcritical booster systems have been successfully deployed in commercial and industrial applications in Europe for nearly two decades. Recent environmental regulations have driven the wider adoption of these systems in North America.
A Fluid Situation
The EPA’s 2015 refrigerant ruling marked the beginning of a major transition for the U.S. commercial refrigeration industry. While several new A1 alternatives have been introduced as viable in some applications, there is still quite a bit of work needed to meet the needs of the wide range of refrigeration applications and achieve desired reductions in GWP. Globally, the industry can expect continued regulatory activity in the coming years, especially with the introduction of new lower-GWP alternatives.
It’s also important to remember that many operators are also stating corporate sustainability objectives, while others wish to put an end to compliance concerns once and for all. To implement truly “future proof” refrigeration systems, many operators are trying to limit their carbon footprint with refrigerants that do not exceed the 150 GWP threshold. Today, natural refrigerants are the best way to achieve this goal, even though they present their own unique operating challenges. As A2Ls make their way through environmental regulations and safety standard approvals, operators will have a broader range of options from which to choose.
It remains to be seen which refrigerant alternatives will become the go-to options of the future.
1. July 2015 Final Rule: https://www.gpo.gov/fdsys/pkg/FR-2015-07-20/pdf/2015-17066.pdf
2. September 2016 Rule: https://www.gpo.gov/fdsys/pkg/FR-2016-04-18/pdf/2016-08163.pdf
September 2016 Factsheet: https://www.epa.gov/sites/production/files/2016-09/documents/snap_action_scr_2_factsheet.pdf
Summary of slide 12 of November, 29, 2016 E360 Webinar: GlobalRegs:https://www.youtube.com/watch?v=q2j7jbudYcc&list=PL0EzIbQoBtncySA6Oc8EKyKx71Vb1wkF-&index=1 see the 12:55 mark
Summary of slide 8 of November, 29, 2016 E360 Webinar: Kigali:https://www.youtube.com/watch?v=q2j7jbudYcc&list=PL0EzIbQoBtncySA6Oc8EKyKx71Vb1wkF-&index=1 see the 8:00 mark
5. Summary of slide 13 of November, 29, 2016 E360 Webinar:
Safety:https://www.youtube.com/watch?v=q2j7jbudYcc&list=PL0EzIbQoBtncySA6Oc8EKyKx71Vb1wkF-&index=1 see the 14:00 mark