REFRIGERANTS
Navigating the new refrigerant landscape
How the global HFC phase-down is impacting commercial refrigeration By Dr Rajan Rajendran vice president, system innovation center and sustainability at Emerson.
T
he 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 United States, 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 2015.
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: R404A/507A, R410A, R407A/C/F and HFC134a. Among these, R404A/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, stand-alone 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 ruling 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. But this HFC initiative extends well beyond US borders. In May 2014, the European Union’s F-Gas
42 August 2017
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 reductions.
And, in October 2016, the Kigali Amendment to the Montreal Protocol — 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.
Synthetic blends
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. R448A/449A and R449B are among the ‘R404A like’ (medium-pressure) options, while R513A and R450A are ‘HFC134a 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
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