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Warm-weather CO2 Strategy Helps Retailer to Hit Sustainability Target

Andre Patenaude | Director – Solutions Strategy

Emerson’s Commercial and Residential Solution’s Business

The transition from hydrofluorocarbon (HFC) refrigerants to lower-global warming potential (GWP) alternatives has become a common denominator in many food retailers’ sustainability strategies. Whether your company is in the early phases of its sustainability journey or has already made significant progress in the race to Net Zero, you’ve likely evaluated the potential of CO2-based refrigeration. Among the many misperceptions about CO2 transcritical booster systems is that they are not well-suited for installations in warmer climates. Emerson recently partnered with Zero Zone to help a leading food retailer prove the business case for warm-weather CO2 refrigeration. To view the full article, click here.

Expanding application potential

When calculating the sustainability potential of a refrigeration system, it’s important to look at its total equivalent warming impact (TEWI), including direct carbon emissions from refrigerant leaks and indirect emissions from energy consumption. Although the natural refrigerant CO2 (or R-744) has a GWP of 1, many supermarket owners and operators have questions about the efficiency of CO2 transcritical booster systems, especially in warmer climates.

CO2 transcritical booster refrigeration systems have been installed in Europe for decades and are expanding rapidly around the globe. Today, nearly 1,000 CO2 transcritical booster systems are installed in the U.S., with adoption projected to increase more than 50% by 2025. System designers, original equipment manufacturers (OEMs) and component manufacturers (e.g., Emerson) have made tremendous strides in developing smart CO2 transcritical booster system strategies that:

  • Improve energy efficiencies in warmer climates
  • Optimize system performance and reliability
  • Lower the total cost of ownership (TCO)
  • Simplify system start-up, operation, high-pressure management and maintenance

Retailers who are now looking at CO2 for the first time will benefit from years of installations and supermarket trials that have significantly improved upon CO2 transcritical booster equipment technologies.

Proving the business case

In a recent collaboration, Emerson partnered with refrigeration OEM Zero Zone to help them design and install a CO2 transcritical booster system for a new supermarket in Joplin, Mo. Due to the location’s warm climate, the design team recommended an emerging high-ambient mitigation strategy designed to maximize the efficiency of CO2 during the summer season. The goals of the project were to help the retailer to meet their sustainability targets while maintaining the highest standards for food quality and safety.

The climate in Joplin averages more than 200 annual hours above R-744’s critical point of 87.8 °F. During these warmer temperatures, a CO2 transcritical booster system would typically enter transcritical mode and consume electricity at a higher rate, but the Emerson and Zero Zone system has been designed to operate efficiently across even these high-temperature ranges. With recent advances in system technologies, stakeholders can choose from multiple CO2 strategies designed to mitigate high-ambient temperatures, minimize transcritical operation, and maximize energy efficiencies.

For the Joplin installation, Zero Zone and Emerson opted to utilize an adiabatic gas cooling strategy on the system’s outdoor condenser/gas cooler. When summer heat builds and R-744 pressures begin to rise within the gas cooler, water is misted onto adiabatic cooling pads — effectively keeping R-744 below its critical point during warm stretches and dramatically improving system efficiency. Today, this installation is operating as designed for Zero Zone’s food retail customer, delivering year-round efficiencies and refrigeration reliability.

The system features a full suite of integrated Emerson CO2 technologies — from low- (LT) and medium temperature (MT) compressors to CO2 refrigeration rack controls case controls and high-pressure controls — that are helping Zero Zone to prove the business case for warm-climate CO2 systems. Not only have these technological advances greatly expanded the potential of CO2 applications in diverse climates, but they’re accelerating CO2 adoption for a new generation of end-users and service technicians.

For more information about the high-ambient CO2 mitigation strategy used in this installation, you can read our case study. To learn about Emerson’s commitment to developing integrated CO2 technologies, please visit our CO2 information hub.

Regulatory Round-up: AIM Act, CARB, A3 and A2L Charge Limit Increases

Jennifer Butsch | Regulatory Affairs Director

Emerson’s Commercial & Residential Solutions Business

If you’re like many stakeholders in the commercial refrigeration industry, you know how important it is to keep track of the dynamic regulatory climate. From making refrigerant decisions and selecting next-generation equipment to plan for compliance and meeting sustainability goals, many companies are basing some of their most important decisions on these developments. I recently provided an article to HVACR Business that reviewed several key regulatory updates taking place this year. If you’re hoping to bring the sometimes-confusing regulatory picture into clearer focus, hopefully this will help. You can also view our formatted article here.

AIM Act establishes federal HFC legislation

Signed into law in late 2020, the American Innovation & Manufacturing Act (AIM Act) gave the Environmental Protection Agency’s (EPA) authority to regulate hydrofluorocarbon (HFC) refrigerants in three primary ways:

  1. Phasing down HFC refrigerant supplies by reducing their production and consumption over a 15-year period. Supply-side restrictions began on Jan. 1, 2022, requiring a 10% reduction in HFC production and consumption through 2023. An additional 30% reduction will take effect between 2024 and 2028 with 70% and 80% reductions needed by 2029 and 2034, respectively. These phasedowns are expected to drive up HFC prices significantly as supplies decrease.
  2. Establishing sector-based approvals and HFC restrictions to support the industry-wide transition to lower-global warming potential (GWP) refrigerant technologies. Use restrictions will enable specific sectors to transition more quickly while providing additional flexibility for those who may need more time. The EPA can approve new lower-GWP alternatives per sector-based rulemakings, which are expected to begin in 2022.
  3. Regulating HFC management by establishing and enforcing standards in servicing and repair best practices, such as: lowering leak rate thresholds and requiring proper recovery of “used” HFCs for purification and resale (aka reclaim). Previously, the EPA had created Section 608 to govern these best practices; we expect their revised HFC management rulemaking could be built off the Section 608 framework.

CARB rulemaking takes effect

After several years of collaboration with state and HVACR industry stakeholders, the California Air Resources Board’s (CARB) proposed rulemaking became final in late 2021 and went into effect on Jan. 1, 2022. The final rule establishes HFC phasedown requirements for new and existing facilities, including a company-wide provision for food retailers operating with a fleet of existing stores within California.

  • New facilities — Installation of new refrigeration systems containing more than 50 pounds of refrigerant are required to use refrigerants with less than 150 GWP.
  • Existing facilities — Refrigeration equipment containing more than 50lbs of refrigerant in existing facilities are subject to company-wide, fleet GWP reduction targets by 2030 compared to their 2019 baselines — with two potential paths to compliance: 1) Weighted-average GWP (WAGWP) reduction <1,400 GWP by 2030, where WAGWP is the sum of the total refrigerant charge of every system greater than 50 pounds in every store in California; 2) Greenhouse gas emissions potential (GHGp) reduction by 55%, where GHGp is the sum of the total refrigerant charge of every system greater than 50 pounds in every store in California multiplied by the GWP values of the refrigerant types in use.

Regarding new stationary air conditioning (AC) equipment, refrigerants with a GWP greater than or equal to 750 will be prohibited, starting in 2025.

Evolving safety standards for flammable (A3) and mildly flammable A2L refrigerants

Governing bodies that regulate the safe use of refrigerants in the U.S. have long been evaluating the prospect of increasing charge limits in the flammable A3 (propane, aka R-290) and mildly flammable A2L refrigerants. In 2021, the Underwriters Laboratories (UL) approved the second edition of its UL 60335-2-89 standard, which included higher charge limits that would expand the potential uses of R-290 and A2Ls in commercial refrigeration.

R-290 charge limit increases — R-290 has a long-held maximum charge limit of 150g and has primarily been used in smaller, self-contained units. The updated UL standard raises the charge limits on these commercial stand-alone displays based on whether they have an open or closed design:

  • 500g maximum charge limit in open appliances (without doors)
  • 300g maximum charge limit in closed appliances (with doors or drawers)

From an application design perspective, higher charge limits will help to increase system capacities while capitalizing on R-290’s high efficiency and low-GWP rating (GWP = 3).

A2L charge limit increases — Per the recently updated UL 60335-2-89 safety standard, new A2L charge limit guidelines have been established for self-contained and remote refrigeration systems. For self-contained equipment, charge limits are determined by equipment design (e.g., open or closed with doors or drawers). Degrees of flammability will vary among different A2L refrigerants, so it’s important to calculate charge limits based on the specific A2L characteristics.

For example, R-454C has a lower flammability limit (LFL) of 0.291 kg/m3, thus:

  • A closed-door case can be charged with up to 2.33 kg (5.1 lbs.) of R-454C.
  • An open case with R-454C can be charged with up to 3.78 kg (8.3 lbs.) of R-454C.
  • In remote or field-erected systems, UL 60335-2-89 supports R-454C charge sizes up to 75.7 kg (166 lbs.) per circuit.

The updated standard requires remote A2L systems to be designed with requisite safety strategies and mitigation measures to keep gas concentrations below flammable thresholds:

  • Leak detection at various points of the refrigeration circuit (e.g., compressor, condensing unit and case)
  • Action plans that immediately mitigate flammability risks

The UL 60335-2-89 second edition update is only the first step in a larger series of regulatory approvals needed to enable higher charges of R-290 and the use of A2Ls in U.S. commercial refrigeration. Additional regulatory and/or policy changes will also need to be approved:

  • EPA Significant New Alternatives Policy (SNAP) approval of specific A2L refrigerants and increased R-290 charge limits
  • ASHRAE 15 safety standard update for refrigeration systems
  • Model code updates in the upcoming code revision cycle, such as: Uniform Mechanical Code (UMC), International Mechanical Code (IMC) and International Fire Code (IFC)
  • State and local building code updates

In the meantime, installing an A2L-based refrigeration system would typically require the approval of local authorities having jurisdiction (AHJ), such as fire marshals and/or building inspectors.

To stay informed of the latest regulatory updates that could impact your operational decision-making, please visit our regulations hub.

 

 

 

Simplifying CO2 Refrigeration

Andre Patenaude | Director – Solutions Strategy

Emerson’s Commercial and Residential Solution’s Business

Interest in CO2 transcritical booster systems is growing rapidly within the U.S. commercial refrigeration industry. In recent years, many supermarkets have tested the waters with CO2 system trials in select stores. Others have already made CO2 the foundation of their long-term refrigeration strategy. But with sustainability goals becoming higher priorities, we expect up to 800 new CO2 transcritical booster systems to be installed in the next 3–4 years.

Although CO2 (refrigerant name R-744) offers a variety of sustainability and reliability benefits, a lack of familiarity with the nuances of CO2 technology can make it seem complex to end-users and service technicians alike. I recently spoke with R744.com about how Emerson is helping to alleviate these concerns by simplifying the applications of CO2 refrigeration systems.

Smart controls to make it easier

To help facilitate these increased adoption levels, Emerson recently launched the Lumity™ E3 supervisory control, designed specifically for CO2 applications. As the successor to our venerable E2 controller system — which is already used in CO2 transcritical booster systems globally — this next-generation refrigeration and facility control device offers native CO2 functionality to better manage a wide spectrum of CO2-specific capabilities:

  • High-pressure system and valve control
  • System start-up and shut-down protocols
  • Hot-gas and liquid injection modulation (de-superheating)
  • Adiabatic gas cooling control
  • Parallel compression management

R-744 refrigerant and CO2 refrigeration system properties are unique and need their own specific control logic and programming requirements. Within the Lumity E3 controller for CO2, we’ve integrated machine-learning algorithms and other native programming that will make CO2 systems easier to own, operate and troubleshoot — while still providing the customization options end-users need to tailor controls to their store requirements. The E3 controller platform is also web-enabled to support remote monitoring and servicing via smartphone, tablet or other web-enabled browsers.

We are also launching a new Lumity CC200 case controller, which includes a specific model for CO2 system cases. This device integrates seamlessly with the E3 supervisory control platform to provide key case-level functions, such as:

  • Demand defrost control
  • Management of up to three evaporator coils with three stepper motor or pulse width modulated (PWM) electronic expansion valves (EEVs)
  • Integrated evaporator pressure regulating (EPR) valve

The CO2 versions of these control products are currently being field-tested and will be available globally later this year. Upcoming E3-CO2 functions include mechanical subcooling and ejector control. Also, hot-gas defrost will be added to the E3-CO2 platform to support the North American trend of using hot-gas defrost — rather than traditional electric defrost — in industrial and commercial CO2 transcritical booster applications.

The upcoming E3-CO2 model is designed to enable current E2 end-users to easily replace their control device when it becomes available. End-users of the standard E3 controller will have the option to upgrade it to the CO2 version.

Expanded CO2 compression capacities

To further support increased CO2 adoption in supermarkets, Emerson will be expanding the capacity of our current Copeland™ 4MTLS transcritical CO2 semi-hermetic compressor lineup. Within months, we will be launching a new option that delivers our largest displacement in the 4MTLS product line — with 330,000 BTU at 20 °F.

In addition to our transcritical CO2 semi-hermetic lineup, we offer Copeland ZOD subcritical CO2 digital scroll compressor products designed to exploit the characteristics of CO2 refrigeration in low-temperature (LT) applications. And, since all lead and parallel compressors in CO2 transcritical booster systems require a variable frequency drive (VFD), we also leverage the new Copeland EVM/EVH Series VFDs in these CO2 system applications.

In Europe, Emerson recently launched Copeland transcritical CO2 scroll compressors for the food retail market. We expect these to be available for use in U.S. markets within the next 18 months. Later this year, we will be launching a new CO2 test lab that will enable us to fully examine the use of these scroll compressors in CO2 transcritical scenarios.

To learn more about how we’re helping to simplify the use of CO2 refrigeration, please visit our CO2 resources webpage.

 

 

Tracking CO2 Refrigeration Trends in the U.S.

Andre Patenaude | Director – Solutions Strategy

Emerson’s Commercial and Residential Solution’s Business

Until recently, CO2 refrigeration systems in the U.S. have been perceived as exceptions to the rule in commercial refrigeration. But as corporate sustainability initiatives and refrigerant regulations continue to reshape refrigeration decisions, many supermarket retailers are exploring CO2’s long-term potential. I recently contributed an article for Supermarket News in which I examined the regulatory, market and technological trends behind its increased adoption in the U.S. To view the full article, click here.

To date, most CO2 installations in the U.S. have been deployed as proofs-of-concept. Although there are some sustainably-minded retailers that have made it the basis of their refrigeration strategy, CO2 hasn’t yet experienced the industry-wide acceptance we’ve seen in Europe. But that appears to be changing.

Among the environmental strategies identified to combat climate change, the greening of commercial and industrial refrigeration equipment has been recognized as an essential tactic of decarbonization plans and corporate sustainability initiatives. Food retail stakeholders are rethinking their approaches to refrigeration and transitioning away from legacy hydrofluorocarbon (HFC) refrigerants with high global warming potential (GWP). More than ever, retailers are evaluating long-term refrigeration strategies that support:

  • Environmental, social and governance (ESG) efforts
  • Energy efficiency and emissions reductions targets
  • Net-zero goals

Stage is set for wider adoption

With zero ozone depletion potential (ODP) and a GWP of 1, the natural refrigerant CO2 (aka R-744) is a proven alternative to higher-GWP HFC refrigerants. CO2’s inherent energy efficiency in most climates allows it to deliver direct and indirect emissions reductions — a lower total equivalent warming impact (TEWI). For more than a decade, CO2 refrigeration has become a leading sustainability strategy for European retailers. Today, that trend continues with adoption steadily increasing in the U.S. and other countries.

Per recent industry data, nearly 46,500 CO2 transcritical booster systems are currently installed worldwide.

  • 900 in the U.S. (1,400 in North America with the inclusion of Canada)
  • 40k in the E.U.
  • 5k in Japan

If CO2 growth trends continue as they have from 2020–2021, the U.S. commercial refrigeration industry can anticipate CO2 adoption to increase up to 50% by 2025. This trend is expected to follow a similar trajectory throughout the next decade, with the possibility that the U.S. could potentially mirror E.U. levels of adoption.

Regulations drive down GWP levels

Global, federal and state regulations are steering the industry away from HFCs and toward lower-GWP alternatives. Using the Kigali Amendment to the Montreal Protocol as a framework, the next step in the HFC production and consumption phasedown schedule will be a 40% reduction in 2024 (compared to the baseline established in 2011–2013).

The passing of the American Innovation and Manufacturing (AIM) Act in 2020 restored the Environmental Protection Agency’s (EPA) authority to enforce HFC mandates and establish sector-based guidelines. As the EPA follows the Kigali Amendment’s HFC phasedown, decreased supplies will continue to drive up HFC refrigerant prices.

The California Air Resources Board (CARB) continues its progressive efforts to phase down HFCs in the state of California. Under its recently adopted rule, all new refrigeration systems containing more than 50 pounds of refrigerant installed in new facilities must use refrigerants with less than 150 GWP. For existing installations with equipment greater than 50 pounds of refrigerant, retailers can take a fleet approach toward reducing their carbon footprint. CO2 refrigeration is becoming a leading option for achieving these regulatory targets.

Technological improvements and emerging applications

The proliferation of CO2 refrigeration systems around the globe has given equipment manufacturers opportunities to improve compression, controls and valve technologies. Emerson is at the forefront of efforts to simplify system management and help the industry transition from legacy high-GWP HFC systems.

Electronic system controllers

Emerson’s new Lumity™ E3 supervisory control for CO2 systems is designed to manage CO2’s high pressures and system volatilities, greatly simplifying commissioning and system management during standard operation. These improvements minimize system complexities, alleviate the burden from technicians, and provide peace of mind to end users.

Integrated CO2 transcritical booster system components

CO2 transcritical booster systems — where both medium- (MT) and low-temperature (LT) circuits run on R-744 — are the most widely adopted CO2 architectures in medium- to large-format food retail stores. Emerson is helping original equipment manufacturers (OEMs) and operators to ensure the system integration needed to maximize reliability and performance, including: compressors, electronic expansion valves (EEVs), high-pressure valves and an electronic controller.

Warm ambient strategies

CO2 transcritical booster systems are subject to declining efficiencies in warm ambient climates, but manufacturers have developed a variety of strategies to maintain efficiency levels.

  • Adiabatic gas coolers — keep the refrigerant below its critical point for as long as possible to maximize system efficiencies
  • Parallel compression — compresses excess flash gas at higher pressure via a dedicated intermediate- stage compressor, resulting in 8–10% annualized efficiency gains
  • Mechanical sub-cooling — provides increased refrigerant enthalpy
  • Gas ejectors, liquid ejectors — optimize efficiency
  • Low superheat of MT evaporators — delivers year-round efficiency improvements

Increasing our commitment to CO2 innovation

Emerson is expanding CO2 labs, testing facilities and development capabilities to further CO2 adoption and support our OEM and end user partners. As the market for CO2 refrigeration continues to expand, the proliferation of new products is creating economies of scale, which lower the costs and complexities of implementing CO2 technologies. To learn more about improving the efficiency, usability and simplicity of CO2 systems, please visit our CO2 resources hub.

 

 

 

 

 

 

 

CO2 Refrigeration Fundamentals: Energy Efficiency Strategies

Andre Patenaude | Director – Solutions Strategy

Emerson’s Commercial and Residential Solution’s Business

Welcome to the final installment of our CO2 Refrigeration Fundamentals blog series. So far, we’ve examined R-744’s unique properties, servicing tips, system operation and design strategies — all of which correspond with topics in our CO2 Chats educational videos. For our final blog, we’ll explore strategies for achieving CO2 transcritical booster system energy efficiencies in warm climates.

How do you achieve energy efficiency in a CO2 system?

The energy consumption of a refrigeration system is a key factor when evaluating its total cost of ownership (TCO). For a CO2 transcritical booster system, energy efficiency is dependent on many factors, including:

  • The ambient temperature range
  • The humidity of the region
  • The availability of and cost of water
  • The cost of peak demand charges

Among these factors, the goal of improving system energy efficiencies in warmer climates has become a major focus area for equipment manufacturers. Leading high ambient strategies include:

  • Adiabatic gas cooler
  • Parallel compression
  • Mechanical sub-cooling
  • Zero superheat control of medium-temperature (MT) evaporators
  • Ejector controls

Retailers must consider all of these variables and strategies when they work with their equipment suppliers and design engineers to specify a CO2 transcritical booster system — which also includes ensuring that qualified service technicians are available in their region to support CO2 refrigeration.

What is an adiabatic gas cooler used in CO2 systems?

An adiabatic gas cooler is very similar to a dry gas cooler, except that it uses adiabatic pre-cooling pads outside the condenser coils. When the ambient temperature reaches about 72 °F on a CO2 transcritical booster system, a water solenoid valve is energized, causing water to be sprayed along the top of the adiabatic pads. As the water trickles down the pads, a condenser pulls air through these wetted pads, causing moist, cooler air to hit the coils. In turn, the condenser reacts to this cooler air and drops the temperature and pressure, making the system significantly more energy-efficient by operating at lower pressures.

What is parallel compression in a CO2 system?

In a CO2 transcritical booster system, parallel compression refers to the practice of adding a separate suction group to the system. This could be confusing to service technicians, who may think we’re simply referring to a parallel rack used on a traditional hydrofluorocarbon (HFC)-based system.

The concept is relatively simple. A “parallel” compressor is added to the MT suction group, which essentially provides a separate suction group to the system. Thus, instead of the bypass gas circulating from the flash tank to the MT suction as in a standard transcritical booster system, the parallel compressor suction group compresses excess flash gas and circulates it to the gas cooler.

This allows the parallel compressor to operate at a suction pressure of about 550 psi (the same as the flash tank), instead of the MT suction of 425 psi. The net effect of leveraging the higher suction pressure is achieving higher compressor capacity for less effort, which translates into a lower heat of compression and reduces energy consumption. As a result, parallel compression is considered a leading high ambient strategy. When annualized in a typical environment, it can potentially save up to 10% in energy costs. Further, parallel compression can be used in combination with an adiabatic gas cooler to achieve additional energy efficiencies.

Thank you for following our CO2 Refrigeration Fundamentals blog series. To learn more about any topic discussed herein, please view the companion installments in our CO2 Chats video series. For more information about Emerson’s comprehensive CO2 products and capabilities, please visit Climate.Emerson.com/CO2Solutions.

 

 

 

 

 

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