Emerson’s Commercial and Residential Solution’s Business
For decades, natural refrigerants have been used worldwide as environmentally friendly alternatives to high global warming potential (GWP) refrigerants or ozone-depleting substances (ODS). As the U.S. commercial refrigeration industry faces an imminent phasedown of hydrofluorocarbon (HFC) refrigerants, the stage is set for natural refrigerants like CO2 and R-290 to play much larger roles. Emerson is pleased to announce our participation in the ATMOsphere America Summit 2022 on June 7–8, where our experts will present new data that supports the expanding business case for natural refrigerants.
With the phasedown of high-GWP HFC refrigerants underway, commercial and industrial refrigeration stakeholders are actively planning for the next generation of refrigerant technologies. As corporate-led environmental initiatives are pledging to use more sustainable equipment, CO2 and R-290 are widely considered to be among the leading natural refrigerant candidates to anchor future refrigeration strategies.
Today’s market is evolving rapidly — and Emerson is at the leading edge of technological advancements supporting the use of these proven natural alternatives. We’ve made significant investments in research and development (R&D) projects and lab testing capabilities designed to:
Promote the use of low-GWP refrigerant technologies
Support original equipment manufacturers (OEMs) in their design cycles
Help end-users to make successful refrigerant transitions
Join us at the ATMOsphere America Summit 2022
As a gold sponsor of the upcoming ATMOsphere America Summit 2022, Emerson is looking forward to presenting data from our recent R&D efforts which explore the expanding role of natural refrigerants. This in-person-only event will take place on June 7–8 in Washington, D.C., at the Hilton Alexandria Mark Center. Join peers, industry experts, policymakers, end-users, and contractors to explore the latest natural refrigerant trends and technologies.
Emerson’s participation will feature informative sessions and panel discussions highlighting our latest natural refrigerant research:
Making the case for sustainable CO2 in supermarket refrigeration (June 7 at 2 p.m. EDT) — which will be presented by me and Zero Zone
Exploring the climate zone impacts on CO2 system selection (June 8 at 10 a.m. EDT) — which will be presented by me
Panel discussion sharing the latest policy and market trends impacting natural refrigerants (June 7 at 11 a.m. EDT) — which will be presented by me
If your company is interested in exploring a future based on natural refrigerants, register now and make plans to attend this in-person event. Be sure to stop by any of the Emerson sessions and ask how we can help you on your journey to more sustainable refrigeration.
Emerson’s Commercial and Residential Solution’s Business
Emerson recently participated in the ATMO World Summit 2022, a 24-hour event focused on exploring developments in the uses and applications of natural refrigerants. Emily Vilardi, Emerson product marketing manager and I presented a webinar highlighting Emerson’s commitment to CO2 refrigeration via the launch of new products and our expanded research and development (R & R&D) efforts. For those unable to attend the event or our session, ATMO has made it available for free on-demand.
Corporate sustainability objectives and environmental regulations are driving the adoption of refrigerants with lower global warming potential (GWP). As food retailers evaluate emerging solutions and transition to the next generation of refrigeration technologies, CO2 transcritical booster systems offer a proven, natural alternative. Although this innovative system architecture uses CO2 (refrigerant name R-744) for both medium- (MT) and low-temperature (LT) refrigeration loads, it introduces a whole new approach to refrigeration for many end-users and technicians.
Emily and I discussed how Emerson is committed to helping facilitate this transition by simplifying the application of CO2 refrigeration through the seamless integration of system components. We focused on three primary areas: compression and variable frequency drives (VFDs), controls and software, and R&D lab investments.
CO2 compression and VFD technology
For the MT transcritical portion of a CO2 transcritical booster system, Emerson offers the Copeland™ 4MTLS transcritical CO2 semi-hermetic compressor in nine displacements from 40,000 to 300,000 BTUs at 60 Hz. These four-cylinder compressors feature onboard diagnostics and have a capacity range from 17.5 to 354 MBH at 20 °F evaporating, 95 °F gas cooler outlet at 60 Hz. In addition, they can be paired with Copeland VFDs, EVM/EVH Series to enable variable-capacity modulation. EVM/EVH drives offer the security of providing 200 percent maximum overload protection for two seconds.
On the LT side, Emerson offers the Copeland ZO(D) subcritical CO2 scroll compressors: ZO for fixed capacity and ZOD (digital) for variable-capacity modulation or their ability to unload capacity down to 10 percent. For example, the ZOD34 is rated for a 34,000 BTU displacement that can modulate (or unload) its capacity to 3,000 BTUs. These subcritical digital scrolls offer a smaller, lighter-weight footprint and don’t require VFDs for capacity modulation. In addition, Copeland MSLS subcritical semi-hermetic compressors are available in displacements from 60,000 to 180,000 BTUs, have a range of 25 to 70 Hz, and are rated for very high standstill pressures.
Integrated CO2 controls
CO2 transcritical booster systems rely heavily on electronic controls to optimize system installation, integrate with cases and high-pressure valves (HPVs), and manage system pressures. Emily explained Emerson’s integrated approach to CO2 controls that enables seamless communication and enhanced visibility to all aspects of system operation.
The soon-to-be-released Lumity™ supervisory control for CO2 applications will expand upon the legacy E2e control to offer enhanced CO2 capabilities, reduce programming complexities, and simplify system management via:
Centralized CO2 suction group control for transcritical booster and parallel compression
Advanced compressor superheat management for liquid or hot gas injection
Precise load management and automatic recovery from out-of-range conditions
Enhanced CO2 system monitoring for system insights
Oil management for long compressor life
The Lumity E3-CO2 will also leverage the many benefits of the new E3 platform, including a built-in touchscreen, remote mobile access, and a greatly improved user interface (UI) that brings all critical CO2 system monitoring into one unified view. The control will integrate seamlessly with Emerson’s high-pressure controller and valve driver (XEV20), the soon-to-be-released Lumity CC200 case controller, the XM600 series case controllers, and leak detection devices (RLDS and MRLDS).
Investing in the future of CO2
In the ATMO webinar, I also elaborated on how Emerson is helping our customers to prepare for the future of CO2 refrigeration through continued lab investments and R&D efforts. In addition to the CO2 transcritical booster system that has been installed at The Helix Innovation Center since 2016, we’ve recently dedicated more than 100,000 square feet to a CO2-specific supermarket test lab in our facility in Sidney, Ohio. This new lab will be launched this summer and feature:
18 display cases from five different manufacturers
Walk-in cooler and walk-in freezer
Dry gas and adiabatic gas coolers on the roof
Wide range of high-ambient system strategies
Ability to create a 100 percent false load to enable testing at any capacity
These advanced testing capabilities will give Emerson’s application engineers ample opportunities to measure and validate system performance across a full spectrum of application scenarios.
To learn more about how Emerson is helping our customers and the industry to simplify the adoption of CO2 system technologies and optimize refrigeration system performance, please view the ATMO webinar.
I was recently asked by the editor of Accelerate America to offer my opinion on the viability of natural refrigerants, including CO2 (R-744), propane (R-290) and ammonia (R-714). Among the many emerging refrigerant alternatives, natural refrigerants check important boxes for owners and operators who are preparing for the rapidly changing commercial refrigeration landscape. View the full article here and read a summary of its key points below.
For more than a decade, natural refrigerants have factored prominently in the search for environmentally friendly refrigeration in both commercial and industrial sectors. We’ve seen the introduction of R-290 in micro-distributed, self-contained cases; increased global adoption of CO2 in centralized systems; and the emergence of ultra-low-charge ammonia, by itself as well as integrated with CO2 in cascade systems. As we kick off a new decade, we will likely continue to see these refrigerants progress along those established lanes.
Drivers for natural refrigerant adoption
Since their introduction, the drivers for natural refrigerant adoption have not changed. Most legacy refrigeration strategies rely on the use of high global warming potential (GWP) hydrofluorocarbon (HFC) refrigerants, and companies with sustainability objectives or regulatory mandates were among the first to make the transition to natural refrigerants — which by many are considered immune from regulatory-mandated GWP caps.
In 2020, the phase-down of HFCs remains a focus of global environmental regulations. From the Kigali Amendment to the Montreal Protocol and the European F-Gas regulations to the California Air Resources Board (CARB) and Environment and Climate Change Canada (ECCC), many countries, states and regions share the goal of an HFC phase-down.
It’s often said that there’s no such thing as a perfect refrigerant — and that’s certainly the case with natural options. But natural refrigerants are among the very few alternatives capable of meeting some of the more aggressive GWP targets. R-290 has a GWP of 3; CO2 has a GWP of 1; and ammonia has a GWP of 0. So from environmental and regulatory perspectives, this puts them in a class by themselves.
Characteristics and caveats
With decades of field use and research to draw from, the performance characteristics of natural refrigerants are well known. But each option has operating caveats that equipment owners must carefully consider before investing in a long-term refrigeration strategy.
R-290 offers excellent energy efficiencies, but as an A3 (flammable) refrigerant, safety regulations limit its use to small charges globally from 150g to 500g. R-290 is a natural fit for small-capacity, self-contained cases that require a lower charge and are hermetically sealed at the factory.
CO2 is a high-pressure refrigerant with a low critical point (87.8 °F) that determines its modes of operation (subcritical, or below the critical point; transcritical, or above the critical point). It also has a high triple point where the refrigerant will turn to dry ice. Systems must be designed to manage these characteristics, and operators must have access to qualified technicians.
Ammonia has been used in industrial refrigeration for the past century, but its toxicity (B2L classification) presents challenges to equipment owners. Tightening safety regulations and the risk of exposure have led to system architectures designed to lower charges and move it out of occupied spaces.
Selecting a natural architecture
When evaluating natural refrigerant architectures, store formats and application requirements will often dictate the refrigerant choice. R-290 is well-suited for either smaller-format stores or as a spot merchandising option for larger stores. CO2 makes the most sense in larger stores seeking a centralized architecture alternative to HFCs. Ammonia is relatively rare in commercial applications but is finding its way into innovative architectures designed to mitigate its risks and benefit from its excellent performance characteristics.
R-290, from integrated cases to micro-distributed — For nearly a decade, manufacturers have worked within the 150g charge limit to create self-contained, integrated cases, in which the refrigeration system (compressor and condensing unit) is built into the display case. These evolved into a micro-distributed approach for small stores, where multiple units share a water/glycol loop to remove excess heat. This approach provides very low-GWP, total-store cooling while keeping charges low, typically operating with 90% less refrigerant than a centralized system.
CO2 transcritical booster — CO2 came into prominence more than a decade ago in large supermarkets where centralized architectures are preferred. CO2 transcritical booster system technology continues to improve today, offering an all-natural solution for both low- and medium-temperature cooling. Compared to centralized HFC systems, CO2 transcritical boosters represent a completely different approach to system operation and servicing. Operators must acquire technicians that are trained to service CO2 systems and implement strategies for power outages in order to mitigate “stand-still” pressure while the system is off.
CO2/ammonia hybrid subcritical (cascade) — CO2 cascade systems are designed to utilize CO2 in the low-temperature (LT) suction group where the refrigerant stays below its critical point and operates at lower pressures, much like a traditional HFC. Typically, an HFC (or HFO/HFC blend) is used in the medium-temperature (MT) circuit, where heat produced from the LT circuit is discharged (i.e., cascaded) into a heat exchanger and into the suction stage of the MT circuit. However, the recent introduction of ammonia as the MT refrigerant has transformed this configuration into an all-natural refrigerant option.
With each of these natural refrigerant options, safety must be the primary consideration. Manufacturers have poured a great deal of effort into ensuring the safe operation and maintenance of natural systems with a variety of strategies, including pressure relief valves, specially designed components, leak detection devices, and proper guidance to owners and operators.
The global regulatory climate and trend toward environmentally friendly refrigeration will help natural refrigerants to proliferate along these well-established paths of least resistance. Still, there is much to consider for system operators, who must weigh the opportunity costs for selecting a natural refrigerant option.
One of the most complex decisions food retailers have today is selecting which refrigerant will serve as the basis of future refrigeration platforms. While there are very few refrigerants that can deliver regulatory compliance and align with corporate sustainability goals, three natural options are at the top of this short list: carbon dioxide (CO2 or refrigerant name R-744); the hydrocarbon propane (refrigerant name R-290); and ammonia (NH3 or refrigerant name R-717).
In recent decades, as synthetic chlorofluorocarbon (CFC) and hydrofluorocarbon (HFC) refrigerants were found to have either ozone depletion potential (ODP) or global warming potential (GWP), natural refrigerants have made their way back into the commercial refrigeration conversation — even being listed by the Environmental Protection Agency (EPA) as acceptable for use in most commercial refrigeration applications (subject to use conditions).
Make no mistake: these refrigerants are by no means perfect — each has its own caveats — but in terms of thermodynamic properties, operational efficiencies and eco-friendliness, natural refrigerants are often referred to as “future proof”.
As modern refrigeration technologies continue to improve, equipment manufacturers are working closely with early adopters to develop innovative solutions. This has resulted in several creative natural refrigeration applications that belie their traditional uses — like ammonia being used in supermarket systems and CO2 playing a larger role in industrial process cooling.
Ammonia trials in food retail In September 2015, the Piggly Wiggly supermarket company opened a new 36,000 square-foot store in Columbus, Ga., that utilizes an NH3/CO2 cascade system manufactured by Heatcraft Worldwide Refrigeration. The all-natural refrigerant system uses an ultra-low charge of ammonia (53 pounds) located away from occupied spaces (on the facility’s roof).
CO2 adoption in industrial cooling In cold storage applications, where ammonia has been the preferred refrigerant for decades, companies are also seeking to lower ammonia charges. As older ammonia systems near replacement, many operators are determining the best option to expand their facility’s low-temperature capabilities. They’re accomplishing this by adopting NH3/CO2 cascade systems that not only utilize very low charges of ammonia, but also keep the R-717 circuit out of occupied spaces.
Propane in food retail When major retailers like Target publicly announce their intentions to use only propane in their self-contained units, it’s an indication that the perceptions about the mainstream viability of R-290 are shifting. The smaller charge limits make R-290 a logical fit for Target’s smaller, stand-alone refrigerated display cases and coolers.
While efforts are needed to mitigate their associated risks and ensure their safe use, natural refrigerants represent true sustainable alternatives that do not sacrifice performance. As regulatory bodies and industry organizations work to refine these standards, natural refrigerants will continue to play a key role in the future of commercial and industrial refrigeration
Table 1 outlines the advantages and disadvantages of R744 as a refrigerant. The list of disadvantages appears smaller than the advantages list, but these issues should not be overlooked, as they have a significant impact on the safety and reliability of R744 systems.
Table 1: Advantages and disadvantages of R744 as a refrigerant
Future articles in this series will cover additional topics concerning R744 in more detail, including the general aspects of R744 systems; more specific information about the design of R744 cascade, transcritical booster and secondary systems; and key points about their commissioning, operation and service.
Director – CO2 Business Development, Emerson Climate Technologies
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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