Lee Van Dixhorn | Director of New Solutions Development, Vilter
Emerson’s Commercial and Residential Solution’s Business
With its excellent thermodynamic properties and high efficiencies, ammonia (aka NH3; refrigerant name R-717) has long been the preferred refrigerant in low-temperature (LT) cold storage warehouses and light-industrial refrigeration applications. But because operators assume a degree of risk when using ammonia, many are evaluating the potential of CO2 (refrigerant name R-744) as a green, lower-risk alternative. In a recent article for Engineered Systems, I explored the emergence of CO2 in the industrial sector.
Despite increasing global adoption in commercial refrigeration, CO2 has yet to make significant inroads in the industrial sector. Its high operating pressure and unique characteristics pose equipment design and system architectural challenges for original equipment manufacturers (OEMs). But today’s industrial OEMs are building upon the framework of successful CO2 architectures used within food retail applications, such as CO2 transcritical booster and cascade systems. Theoretically, it’s a matter of scaling these systems up for industrial use.
Market drivers of CO2 adoption
Efforts to increase the supply of CO2-based industrial refrigeration equipment are driven largely by new market demands.
Last-mile delivery considerations — In response to the accelerated adoption of e-commerce in food retail applications, many light-industrial distribution and fulfillment (D&F) facilities have arisen in urban areas to shorten the distance to consumers. But the risk of an ammonia leak in highly populated areas threatens to not only shut down a facility but also evacuate the surrounding area. Operators of these light-industrial facilities are seeking a lower-risk, green alternative.
Lowering ammonia charges and designing for safety — The Occupational Safety and Health Administration (OSHA) has mandated safety requirements for systems charged with more than 10,000 pounds of ammonia. This has led to the exploration of all-CO2system architectures and those that combine CO2 and ammonia to lower ammonia charges and move refrigeration circuits out of occupied spaces.
Global hydrofluorocarbon (HFC) refrigerant phasedown — The recent passing of the American Innovation and Manufacturing (AIM) Act has brought the global HFC phasedown back into focus in the U.S. Meanwhile, the California Air Resources Board (CARB) and/or U.S. Climate Alliance states are pushing forward with their own aggressive phasedown schedules. Industrial operators who have traditionally preferred using HFCs over ammonia are evaluating alternative refrigerant options, such as CO2.
Blurring of lines between commercial and industrial OEMs — With CO2emerging in the industrial sector, and low-charge ammonia systems being trialed in commercial architectures, OEMs are leveraging their legacy experience to cross into adjacent markets. However, commercial OEMs need to understand the increased demands of industrial applications and develop equipment that is built to withstand their rigors.
Sustainability initiatives — Regardless of all other market and regulatory considerations, many companies today are establishing and adhering to corporate sustainability objectives. This requires selecting refrigeration architectures that are both safe and environmentally friendly. As a green natural refrigerant, CO2is helping businesses to achieve these objectives.
Supporting the transition to CO2
Although it’s unlikely that CO2 will ever completely replace ammonia as the preferred refrigerant in large-charge industrial applications, CO2-based refrigeration equipment is becoming a more viable option in light-industrial scenarios.
With extensive expertise in both ammonia- and CO2-based refrigeration, Emerson is uniquely qualified to support traditional and emerging industrial applications. Our Vilter™ single-screw compression technology is not only built to withstand the rigors of industrial refrigeration, but it’s also capable of managing the high pressures of CO2 transcritical booster applications. In addition, our ever-expanding CO2 product portfolio includes a breadth of solutions for transcritical, cascade and secondary architectures.
From compression technologies, controls and variable-speed drives to supervisory services and a wide range of CO2-approved system components, we are a CO2 refrigeration solution provider and partner to leading industrial operators and food retailers.
Proactive refrigerant management isn’t just good for the environment. It is also sound business practice. I was recently interviewed by ACHR’s The News magazine on the Environmental Protection Agency’s (EPA) partial rollback of Section 608 provisions for appliance leak repair and maintenance. You can read the full article here and more on our perspective below.
In February, the EPA eliminated leak repair and maintenance requirements on appliances containing 50 or more pounds of substitute refrigerants, such as hydrofluorocarbons (HFCs). As a result, equipment owners are no longer required to:
Repair appliances that leak above a certain level
Conduct verification tests on repairs
Periodically inspect for leaks
Report chronically leaking appliances to the EPA
Retrofit or retire appliances that are not repaired
Maintain related records
But just because these leak repair provisions are no longer required doesn’t mean food retailers should ignore these best practices. There is a price to pay for refrigerant leakage that extends far beyond environmental damage. Detecting, repairing and even proactively reducing refrigerant leaks will help operators avoid a variety of associated costs.
The high cost of refrigerant leaks
The rollback of legal penalties for refrigerant leaks does not change the math on the operational costs. An average food retail store leaks an estimated 25 percent of its refrigerant supply each year, which can quickly add up to thousands of dollars in lost refrigerant. In addition, retailers must consider the maintenance and equipment costs. Persistently low levels of refrigerant can cause:
Excess compressor wear and tear
Reduced compressor and system capacities
Premature system failures
Double-digit efficiency losses
Left unchecked, even minor leaks can eventually lead to equipment failure. When this occurs, emergency repair costs are often only the tip of the iceberg. Operators may also be looking at revenue loss from food waste, business disruptions and reputational damage.
Proactive refrigeration management
So what can operators do to prevent leaks, even in the absence of federal requirements?
In the near term, they can — and should — implement rigorous leak detection and repair programs. Refrigerant leaks can occur anywhere in a system. Thus, an effective refrigerant leak detection program will combine monitoring, detection and notification.
Multiple technologies are available to support these efforts, including active and passive devices for monitoring and detection. Internet of things (IoT) capabilities allow for remote monitoring, enabling operators to focus on more pressing tasks. And with the integration of data analytics platforms, operators can uncover trends, identify persistent problem areas, and make informed choices about equipment upgrades and replacement options.
Over the longer term, operators can adopt refrigeration architectures that reduce the potential for refrigerant leakage in the first place. Legacy, centralized direct-expansion rack systems are high leak-rate offenders. That shouldn’t be a surprise; with thousands of feet of pipe, hundreds of joints and large refrigerant charges, there are many opportunities for leaks to occur.
In contrast, distributed micro-booster, indoor distributed and outdoor condensing unit (OCU) architectures experience lower leak rates by design. As an added benefit, they offer more options for lower-GWP alternative refrigerant use. This is a crucial advantage for operators who want to position their business for future regulations.
Sustainable best practices
The EPA’s Section 608 leak repair provisions were good for the environment. They are also part of a larger body of best practices for optimizing HVACR equipment. As states take the lead in adopting standards for leak detection and control, operators may find the rollback of these regulations to be short-lived.
Emerson is proud to take a lead in developing sustainable and cost-effective refrigeration systems and supporting technologies. Operators and original equipment manufacturers count on us to deliver strategies and solutions that anticipate emerging trends and regulations. From pioneering refrigeration architectures to refrigerant leak detection tools, we are committed to providing operators with the capabilities to meet their sustainability and operational goals today and into the future.
For several years, the regulatory landscape regarding the governance of refrigerants has been constantly shifting. Already in 2020, we’ve seen developments, both on the state and federal levels in the U.S., which will have significant impacts on the commercial refrigeration and air conditioning sectors for years to come. We recently published an E360 article that lays out these regulatory developments in detail; this blog is a condensed summary of its key points.
Global, national and state regulations have targeted the phase-down of hydrofluorocarbon (HFC) refrigerants with high global warming potential (GWP) and replacing them with lower-GWP options. But while emerging refrigerants — such as natural alternatives and new synthetic blends of HFCs and hydrofluoroolefins (HFOs) — offer environmental improvements, they are not without their operational caveats. Making the transition to these new alternatives will impact refrigeration architectures and raise concerns about performance and safety.
This dynamic combination of factors creates a complex regulatory mix that industry stakeholders have been actively working to resolve. To better understand the full context, we’ve summarized the major regulatory developments in the U.S. and abroad.
Update on EPA SNAP Rules 20 and 21
In 2017, the U.S. District Court of Appeals for the D.C. Circuit ruled to vacate the Environmental Protection Agency’s (EPA) Significant New Alternative Policy (SNAP) Rule 20 — ruling that the EPA did not have authority to require those who had already moved out of ozone depleting substances (ODS) to phase down to lower-GWP HFCs under its Clean Air Act (CAA). Subsequently, the EPA published a “Notification of Guidance,” stating that it would not enforce any of the HFC restrictions set forth in SNAP Rules 20 and 21 when drafting future regulations.
The Natural Resources Defense Council (NRDC) filed a lawsuit claiming that the 2018 Guidance was overly broad because it did not distinguish between ODS and HFC replacements, and that the EPA had not followed proper public notice-and-comment procedures to seek stakeholder input.
On April 7, 2020, the Court of Appeals granted the NRDC’s petition, stating that the EPA guidance was procedurally inappropriate. The court agreed that the initial 2017 decision required only a partial vacatur — not entirely eliminating the requirements SNAP Rules 20 and 21.
It’s important to remember that the industry had already made great strides toward meeting the mandates of SNAP Rule 20 after its passing in 2015, but these ongoing legal entanglements have left the U.S. without a clear path forward in terms of a unified refrigerant strategy. While the majority of the industry still supports the move toward a more sustainable and environmentally friendly future, court rulings around SNAP Rules 20 and 21 have created many questions about what the path forward will look like.
HFCs excluded from refrigerant management requirements
In response to the 2017 Court of Appeals ruling, the EPA also has rolled back other HFC-related regulations. Specifically, it excludes HFCs from the leak repair and maintenance requirements for stationary refrigeration equipment, otherwise known as Section 608 of the CAA. Other beneficial provisions of Section 608 — including the certified technician program and the refrigerant recovery and reclamation rules — are still in effect.
California continues to set the pace
The passing of California Senate Bill 1383 (the Super Pollutant Reduction Act) in 2016 called for Californians to reduce F-gas emissions (including HFCs) by 40 percent by 2030. Since then, the California Air Resources Board (CARB) had been using EPA SNAP Rules 20 and 21 as the bases of its HFC phase-down initiatives. The subsequent passing of California Senate Bill 1013 (the California Cooling Act) in 2018 mandated the full adoption of SNAP Rules 20 and 21 as they read on Jan. 3, 2017; the law is currently in effect.
To meet HFC reductions of 40 percent by 2030, CARB continues to hold public workshops and invited industry stakeholders to comment on the details of its second phase of proposed rulemaking, which currently states:
Refrigerants with a GWP greater than or equal to 150 will not be allowed in new stationary refrigeration systems charged with more than 50 pounds, effective Jan. 1, 2022.
Existing food retail facilities with refrigeration systems charged with more than 50 pounds must collectively meet a 1,400 GWP average or 55 percent greenhouse gas emission potential (GHGp) reduction over 2018 levels by 2030.
Refrigerants with a GWP greater than or equal to 750 will not be allowed in new stationary air conditioning equipment, effective Jan. 1, 2023.
Refrigerants with a GWP greater than or equal to 750 will not be allowed in chillers (including process chillers) greater than -15 °F and ice rinks, effective Jan. 1, 2024.
Refrigerants with a GWP greater than or equal to 2,200 will not be allowed in new chillers ranging from
-15 °F through -58 °F, effective Jan. 1, 2024.
CARB is planning to finalize these rulemaking proposals this summer and is still seeking industry input.
More states join U.S. Climate Alliance
In 2017, a coalition of 16 states and Puerto Rico emerged to form the U.S. Climate Alliance, with a shared commitment of reducing short-lived climate pollutants (SLCPs) and HFCs. Since then, the Alliance has grown to 25 members — comprising more than 55 percent of the U.S. population and an $11.7 trillion economy. Several states have announced plans to follow California’s lead on HFC phase-downs.
Refrigerant safety standards and codes under review
Meeting the targeted emissions reductions in California likely will require the use of low-GWP refrigerants. But many of these low-GWP, HFO refrigerants are classified as A2L, or mildly flammable. The natural A3 refrigerant R-290 (propane) also is becoming more widely used in low-charge, self-contained commercial refrigeration applications. Currently, national and global governing agencies are evaluating the standards that establish allowable charge limits and the safe use of these A2L and A3 refrigerants.
Per a 2019 update from the International Electrotechnical Commission (IEC) to IEC60335-2-89, A2L and A3 charge limits have been increased for commercial refrigeration systems:
A2Ls — from 150g to 1.2kg
A3s — 500g for factory-sealed systems, and will remain at 150g for split systems
Similar efforts to raise A2L and A3 charge limits also are taking place in the U.S. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and Underwriters Laboratory (UL) are working to establish new charge limits and mitigations for the use of A2L and A3 refrigerants with support from industry and various stakeholders.
Once adopted, these standards will serve as the bases for codes that govern building, fire and other local authorities having jurisdiction (AHJ). It’s important to remember that building codes vary from state to state; thus, the adoption of flammable refrigerants ultimately may take place on local levels and may take years to accomplish.
Kigali Amendment not ratified in U.S.
In 2016, 197 member countries of the Montreal Protocol met in Kigali, Rwanda, and agreed on a global HFC phase-down proposal. The Kigali Amendment required ratification from at least 20 countries to take effect. To date, 92 countries (including many countries in the E.U., but not including the U.S.) have ratified it; it has been in effect for participating countries since Jan. 1, 2019.
According to industry estimates, ratifying the Kigali Amendment could create up to 33,000 jobs in the manufacturing sector by 2027 and have a positive impact on the U.S. economy. For these reasons, industry advocates are in favor of ratification and have demonstrated this through letters of support to both the Senate and the White House.
New HFC bills introduced in the U.S.
The U.S. Senate and the House of Representatives have each penned new bills that would put the EPA in alignment with the Kigali Amendment and restore the EPA’s authority to phase down the production and consumption of HFCs over a 15-year period.
Senate: American Innovation and Manufacturing Act of 2019 (S2754)
House: American Innovation Leadership Act of 2020 (HR5544)
While the future and timing of these new bills are uncertain, they offer the potential to re-establish a federal standard for HFC management, including guidelines for servicing, recovery, recycling and reclamation.
Industry appeals for consistency
Industry advocates, including the Air-conditioning Heating and Refrigeration Institute (AHRI) and the NRDC, have appealed for states to be consistent in their approach to adopting CARB’s rules. Establishing a unified framework for future refrigerant regulations would provide the certainty needed to help the industry and regulatory bodies move forward with a consistent approach. At Emerson, we’re actively involved in helping the HVACR industry evaluate and steer these proposals — in industry committees, stakeholder meetings and public comments.
The transition to more environmentally friendly refrigerants in commercial refrigeration and air conditioning applications is underway all around the globe. In the United States, ever-evolving state and federal regulations are forcing industry stakeholders to pay close attention to the developments taking place in their regions. Regardless of your specific location or operational requirements, the use of hydrofluorocarbon (HFC) refrigerants is being phased down in favor of alternatives with lower global warming potential (GWP).
I recently co-hosted an E360 Webinar with Jennifer Butsch, Emerson’s regulatory affairs manager of air conditioning, to discuss the latest regulatory developments and industry trends driving this transition. For those who could not attend this informative session, you can view the webinar in its entirety. And if you need a primer for quickly understanding this transition, I developed the following list to highlight the key points of our discussion:
The refrigerant transition is not new — In the 1980s, scientists discovered that chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants — such as R-22 — were contributing to the depletion of the ozone layer. The Montreal Protocol Treaty was enacted in 1987 to ban the use of refrigerants with ozone depletion potential (ODP); since then, the hole in the ozone layer has steadily recovered. But the ban on these refrigerants led to the introduction of HFCs — such as R-404A and R-410A — which were then proven to cause global warming. As a result, the Kigali Amendment to the Montreal Protocol was established in 2016 to phase down the use of HFCs; it went into effect in 2019 for its 20 participating member countries.
The transition is a global effort — Even before the Kigali Amendment went into effect, other global regions and countries established their own HFC phase-down regulations. The European Union’s F-Gas regulations, which went into effect in 2014, has led the way on establishing a framework for rulemaking. Environmental Canada enacted its own HFC rulemaking in 2017; many of its requirements went into effect this year.
California takes initiative in the U.S. — In the absence of federal regulations, the California Air Resources Board (CARB) has introduced its own HFC phase-down measures, starting with the adoption of the Environmental Protection Agency’s (EPA) Significant New Alternatives Policy (SNAP) Rules 20 and 21. In addition, it is currently working with industry associations and stakeholders to develop proposals to achieve additional GWP reductions by 2030. Many in the industry consider CARB’s proposals among the most ambitious in the world.
States are joining the charge — Following California’s lead, many states have also committed to introduce climate change initiatives, including the reduction of HFCs. Currently, 25 members have joined the U.S. Climate Alliance, which now represents more than 55% of the U.S. population and an $11.7 trillion economy. A few member states have also adopted SNAP Rules 20 and 21 into law; however, each of these states has set forth varying implementation timelines, which will only add complexity to the national regulatory landscape.
New federal regulations are on the horizon — To restore federal guidance pertaining to HFC phase-down regulations, both the Senate and the House have recently introduced new bills, respectively: The American Innovation and Manufacturing Act of 2019, and the American Innovation and Manufacturing Leadership Act of 2020. Both bills align with the HFC reduction goals established in the Kigali Amendment and would authorize the EPA to once again regulate HFCs and establish standards for HFC
management (servicing, repair, recovery, recycle, reclaim, etc.). The general consensus throughout the industry is that a standardized federal approach would minimize compliance complexities created by a potential patchwork of state regulations.
The next generation of refrigerants is already here — Many low-GWP alternative refrigerants not only have been developed already, they are being designed to replace HFCs commonly used in specific applications today. These refrigerants offer varying GWP ranges and cover the spectrum of refrigerant safety classifications, from A1 (non-flammable) to A2L (mildly flammable) to A3 (highly flammable) and B2L (toxic, mildly flammable). It’s important to point out that many of the lowest-GWP alternatives are classified as A2L, and thus will require equipment and facility redesigns to meet application and safety standards.
Safety standards and codes are evolving — With the industry moving toward the use of flammable refrigerants, the technical committees and governing bodies who provide guidelines on how to safely use these refrigerants are actively updating safety standards. While these activities are ongoing, it’s important to remember that once established, these standards will take several years to make their way into both model and local codes needed to permit the widespread use of flammable refrigerants. The industry still has more work to do before that becomes a reality.
System architectures are changing — This transition is ushering in a new era of system architectures. To utilize low-GWP refrigerants, reduce refrigerant charges and the potential for leaks, look for the commercial refrigeration industry to shift from traditional centralized systems toward more distributed approaches. Natural refrigerant architectures — such as CO2 transcritical booster and R-290 integrated cases — will also continue to expand. Manufacturers are utilizing familiar booster technologies and components to help end users transition to lower-GWP A1s today and even lower-GWP A2Ls in the future. In trials, these systems have provided significant energy savings with reduced installation costs and refrigerant charges.
CO2 is an emerging natural refrigerant alternative, but it poses a sharp learning curve for technicians in the U.S. I recently authored an article in RSES Journal that explains why contractors will need to start enhancing their knowledge and adapting their skillsets now to prepare for future servicing needs. You can read the full article, “Fundamentals of CO2 Refrigeration,” here.
Why Contractors Need to Prepare Now for the Coming CO2 Refrigerant Revolution
As the drive to replace hydrofluorocarbon (HFC) refrigerants with lower-GWP (global warming potential) alternatives heats up, CO2 (or refrigerant R-744) is a proven natural option that is experiencing wider adoption in the U.S. — particularly in large centralized systems.
Natural refrigerants — so named because they occur naturally in the environment — also include both propane and ammonia. But for larger-format supermarket operators seeking an all-natural, environmentally friendly option, CO2 checks all the boxes. It’s nonflammable and nontoxic. It presents no threat to the ozone layer. And it meets every current and known future regulatory requirement. In addition, whereas R-404A has a GWP of 3,922, CO2 has a GWP of 1.
While CO2 refrigeration architectures have been successfully deployed in European commercial and industrial settings for nearly two decades, they are a relative newcomer to the U.S. That’s set to change as more operators face regulatory mandates or have stated sustainability objectives.
This will pose a sharp learning curve for many refrigeration contractors and service technicians, especially those who aren’t familiar with the peculiarities of CO2, or the transcritical CO2 booster architecture they’re most likely to encounter soon.
Understanding CO2’s unique properties
When servicing transcritical CO2 booster systems, technicians will need to account for factors that they have never needed to consider with HFC systems. CO2 has a much lower temperature at atmospheric pressure than HFCs. It also has a higher saturation point, as well as higher operating and standstill pressures. Understanding how these characteristics impact system operation servicing requirements and system performance is essential:
Low critical point. CO2’s very low critical point (at 1,056 psig or 87.8 °F) determines its modes of operation; the system will operate in subcritical mode at low ambient temperatures and transcritical mode at higher ambient temperatures.
High triple point. At 61 psig, CO2’s triple point — where the refrigerant’s solid, liquid and vapor phases coexist — is very high. If system pressures reach the triple point, the refrigerant will turn to dry ice, which affects system performance and presents a potential safety hazard.
Rapid pressure rise. During power outages, CO2 pressures can rise quickly. Pressure-relief valves will release the refrigerant charge when it exceeds acceptable pressures, but this can increase the risk of product loss. To prevent system evacuation, CO2 systems often are designed with an auxiliary cooling system.
Vapor to liquid charging. CO2 systems typically use both liquid and vapor to charge, requiring careful coordination to prevent the formation of dry ice.
Transcritical CO2 systems are specifically designed to manage its high pressures and maximize its full potential. Because this system design represents a completely different approach than typical HFC systems, specialized training is required to service these systems and understand their supporting technologies, which typically include high-pressure controllers, electronic expansion valves, pressure transducers and temperature sensors.
Finding the right educational resources
Contractors and technicians who want to add CO2 servicing to their qualifications would do well to start educating themselves now. All signs indicate that its adoption in the U.S. will accelerate in the near future. Given CO2’s peculiarities and unique system design strategies, it is imperative that technicians familiarize themselves with the refrigerant and the operation of a CO2 system.
At Emerson, we are leading the industry in CO2 refrigeration system innovation. But we don’t just offer a full suite of CO2 refrigeration system components. We also are dedicated to helping contracting businesses ensure their service technicians understand how to safely install, commission and service these systems. Our Educational Services team offers a comprehensive CO2 training curriculum for contractors seeking to learn more about working with this emerging refrigerant alternative.
Commercial & Residential Solutions is a global innovator of energy-efficient heating, air conditioning and refrigeration solutions for residential, industrial and commercial applications. www.climate.emerson.com
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