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Zero Zone Partners with Emerson for Warm Climate CO2 Solution

Andre Patenaude | Director – Solutions Integration,

Emerson’s Commercial and Residential Solution’s Business

As environmental regulations and sustainability initiatives drive the shift toward refrigerants with lower global warming potential (GWP), food retailers are looking more closely at CO2 (refrigerant name R-744). But transitioning to a refrigeration strategy that utilizes CO2 transcritical booster systems will require technologies that maintain CO2 system efficiencies in warmer climates. In a recent article that appeared in R744, I explored how Emerson partnered with Zero Zone to develop a solution that overcomes these challenges. To view the full article, click here.

From an environmental perspective, CO2 is a natural refrigerant with zero ozone depletion potential (ODP) and a GWP of 1 — making it a leading alternative to higher-GWP hydrofluorocarbon (HFC) refrigerants. Although these characteristics are appealing to grocery chain operators, their primary refrigeration system requirement is to providereliable cooling that supports food safety and freshness.

Overcoming high ambient temperature concerns

As a leading manufacturer of refrigerated display cases and refrigeration systems for food retail and commercial operations, Zero Zone set out to create CO2 transcritical booster systems that meet retailers’ sustainability and reliability goals. To help them develop a solution for a retailer’s outlet in Joplin, Mo., Zero Zone tapped Emerson — its long-time product development partner — for its deep experience in CO2 compression technologies and system components.

A key enabling feature is the use of an adiabatic gas cooler that is designed to operate in high ambient temperatures and keep the CO2 refrigerant below its critical point for as long as possible. The adiabatic gas cooler rejects the heat load from all the refrigerated cases within the CO2 transcritical booster system.

During warmer periods, air entering the finned heat exchangers is pre-cooled to a temperature approaching the wet-bulb temperature via wetted adiabatic cooling pads. This pre-cooling process dramatically improves refrigeration efficiency without having to spray water mist onto the finned heat exchanger surface.

Leveraging Emerson compression, controls and components

Another unique aspect of CO2 transcritical booster systems is their use of only R-744 for both medium- (MT) and low-temperature (LT) loads. Zero Zone’s CO2 rack refrigeration system features three Copeland™ CO2 transcritical semi-hermetic compressors, two Copeland ZO scroll compressors and one digital scroll compressor that provides 20–100% capacity control over system suction pressure. In addition, the lead CO2 transcritical compressor operates with the assistance of a variable-frequency drive (VFD) to enable variable-capacity modulation. Copeland’s CO2 compressors are designed to manage CO2’s high-pressure requirements and benefit from its thermodynamic properties.

To oversee the operation of the CO2 transcritical booster system — which includes managing 12 electronic case controls and optimizing the facility’s overall energy management profile — Zero Zone installed Emerson’s E2 supervisory control. The E2 facility control is part of Emerson’s portfolio of facility management and refrigeration control devices, including Emerson’s new Lumity™ E3 supervisory control with an integrated touch-screen display — which are designed to improve CO2 transcritical booster performance in multiple ways:

  • Controls the variable speed of the fans on the adiabatic gas cooler in response to operating conditions
  • Manages MT and LT compressors by controlling suction pressure variations to enable tight case temperature control and lower energy consumption
  • Controls the temperature difference on the gas cooler and provides visibility into the operation of the high-pressure controller, enabling the monitoring of gas cooler and flash tank pressures, as well as the operation of high-pressure and bypass valves
  • Provides complete oil management control of all CO2 refrigeration compressors
  • Communicates with and captures information from individual case-control units
  • Provides complete control of building HVAC and refrigeration systems, and supports the retailer’s energy and maintenance reduction strategies
  • Enables access from anywhere (mobile, tablet or PC) via a web-based user interface (UI)

The system also utilizes Emerson’s CO2 high-pressure controller, which provides a variety of system management functions, including:

  • High-pressure and flash gas bypass valves directly based on the gas cooler outlet temperature, as well as the pressure of the receiver
  • Subcritical and transcritical modes of operation based on temperature input
  • High-pressure valve to control constant sub-cooling during subcritical operation and ensure optimum efficiency during transcritical operation
  • Communication with the E2, which allows users to manage and monitor all aspects of the high-pressure controller

All the Emerson controls are designed to integrate seamlessly with each other and with the system’s electronic expansion valves (EEVs), enabling real-time visibility to various aspects of refrigeration system status.

Preparing for wider CO2 adoption

Today, the retailer’s Joplin store is operating efficiently and effectively on the CO2 transcritical booster system provided by the Zero Zone and Emerson partnership. This installation is a proof-of-concept for how manufacturers are overcoming end-user concerns over CO2’s operating pressures, maintenance levels and energy efficiency. Emerson CO2 technologies helped to ease those concerns for Zero Zone and their retail customers.

As we expect to see a significant increase in CO2 system adoption in the U.S. over the next few years, Emerson is committed to supporting our original equipment manufacturer (OEM) and end-user partners to drive further CO2 system innovations.

 

Refrigerant Strategies for Achieving Regulatory Compliance

Andre Patenaude | Director – Solutions Integration,

Emerson’s Commercial and Residential Solution’s Business

Choosing a refrigerant is one of the most important decisions facing food retailers today. With regulatory mandates set to take effect soon, questions about refrigerants and equipment strategies continue to dominate industry conversations. In a recent article that appeared in Contracting Business, I offered tips for achieving regulatory compliance using a variety of lower-global warming potential (GWP) refrigerants. You can also view our formatted article here.

After years of regulatory uncertainty, supermarket owners and operators have developed varying degrees of refrigerant transition fatigue. But with the passing of the American Innovation and Manufacturing (AIM) Act in late 2020, regulatory compliance is again becoming a top priority. The AIM Act brings hydrofluorocarbon (HFC) regulations back into focus at a national level and proposes a significant phasedown of HFC refrigerants over the next five years.

Because compliance will no longer be a concern only for those located within California and U.S. Climate Alliance states, many operators are evaluating their retrofit and replacement options for the first time. But it’s important to understand that there is no one-size-fits-all strategy. In addition to regulatory compliance, operators must consider other key decision criteria, including operational safety, reliable system performance, the total cost of ownership (TCO) and their own corporate sustainability objectives.

At one end of the continuum, some are pursuing a one-time investment that can get them to the end game of compliance. Others may prefer to take a more incremental approach, i.e., focusing on a strategy that meets near-term compliance targets but is also capable of adapting to future standards. No matter how far along your company is on its sustainability journey — or how much progress (or lack thereof) you’ve made on your refrigerant transition — there are a wide variety of options from which to choose.

Retrofit to R-448A/R-449A in existing centralized direct expansion (DX) systems

For operators hoping to preserve their existing investments, replacing R-404A with R-448A will allow them to achieve sustainability improvements with minimal retrofit requirements. R-448A’s slightly higher discharge temperatures require additional compressor cooling, such as: head cooling fans and/or demand cooling modules or the installation of a vapor-injected scroll compressor. While this strategy may be viable for lowering carbon emissions, it may not satisfy future low-GWP regulatory requirements.

Move the condensing unit outdoors

Outdoor condensing units (OCUs) that utilize R-448A are designed to deliver lower-GWP refrigeration by servicing a limited number of medium- (MT) or low-temperature (LT) fixtures. Ideal for small, urban store formats or large supermarkets deploying new refrigeration capabilities outside of their existing DX systems, OCUs offer installation flexibility and reliability in a variety of scenarios. As A2L refrigerants become available for use in the future, this distributed OCU approach will enable even lower-GWP refrigeration.

Distribute scroll racks throughout the supermarket

Scroll racks provide a scaled-down, distributed version of a conventional rack system that can be strategically installed in proximity to different refrigerated sections. This allows retailers to significantly reduce their overall refrigerant charge — today with R-448A and potentially A2Ls in the future — while benefiting from increased system reliability and energy efficiency. In Europe, A2L versions of these systems have already been successfully trialed and deployed.

Deploy micro-distributed (self-contained) units

Ideal for retrofits, remodels and spot merchandising, flexible stand-alone (aka self-contained) units are factory-charged with R-290 and a 150g charge limit. With the recent Underwriters Laboratories (UL) approval of potentially larger R-290 and A2L charges, this micro-distributed approach will support even greater system capacity in the future. They also utilize lower-GWP HFCs. Manufacturers are designing larger self-contained cases that can integrate a single compressor, refrigeration circuit and electronic controls within the unit itself. This approach can then be scaled from one to multiple units with all cases connected to a shared water loop to remove heat from the store.

Simplify with a distributed scroll booster

Another emerging distributed approach utilizes the low-pressure, lower-GWP R-513A for LT and MT circuits in a scroll booster architecture. This system is designed to eliminate the high discharge temperatures and compression ratios typically found in LT systems. Today, distributed scroll booster systems deliver improved energy efficiencies and high reliability within a familiar A1 operating envelope. This architecture also provides future-state regulatory assurance by offering compatibility with very low-GWP A2Ls.

Boost compliance with CO2 (centralized)

CO2 transcritical booster systems offer an environmentally friendly alternative to HFC-based centralized DX systems. Utilizing R-744 for LT and MT loads, this proven architecture allows operators to achieve compliance with regulations for the foreseeable future. However, the refrigerant’s high-pressure and unique performance characteristics increase system complexities and require the assistance of CO2-trained technicians. This system strategy is already widely adopted globally and is becoming more popular among U.S. retailers suffering from refrigerant transition fatigue.

At Emerson, we are developing refrigeration technologies to help industry stakeholders meet their current and future regulatory mandates. Not only can we help you successfully deploy any of the strategies discussed in this blog, but we’re also ready to help you make the transition to a low-GWP refrigeration strategy that aligns with your operational and sustainability objectives.

Join Emerson at the Virtual ATMOsphere America Summit

Andre Patenaude | Director – Solutions Integration,

Emerson’s Commercial and Residential Solution’s Business

In an era shaped by environmental regulations and corporate sustainability initiatives, natural refrigerants have become viable alternatives in the transition away from hydrofluorocarbon (HFC) refrigerants with high global warming potential (GWP). From the increased adoption of CO2 transcritical booster systems to the prospect of larger R-290 charge limits in self-contained applications, natural refrigerants continue to play ever-expanding roles within the U.S. commercial refrigeration sector. This dynamic landscape will be explored in-depth at the upcoming ATMOsphere America Online Summit on Wednesday, Nov. 3, where Emerson will be showcasing some of its latest natural refrigerant solutions in our virtual booth. Register for the event here.

The 10th edition of ATMOsphere America will be held online, gathering key industry experts, policymakers, end-users and contractors for a free, daylong event where attendees can network with peers and learn about the latest developments in natural refrigerant-based solutions. The program will cover market and technological trends, policy and standards updates, the impact of refrigerants, and end users’ perspectives on their experiences with natural refrigerants.

As a champion for the development of natural refrigerant technologies and a gold sponsor for this year’s event, Emerson is pleased to be hosting a virtual booth at this important industry conference. Not only will it give us an opportunity to highlight some of our new natural refrigerant capabilities, but it will also allow us to speak with industry stakeholders about the many developments that impact the use of natural refrigerants. Highlights will include:

CARB compliance — Under the California Air Resources Board’s (CARB) current proposal, the installation of new refrigeration systems containing more than 50 pounds of refrigerant in a new facility must use refrigerants with a GWP rating less than 150. In existing facilities, new installations of systems greater than 50 pounds would be subject to company-wide, fleet GWP reduction targets by 2030 compared to their 2019 baselines. These reductions may be achieved via one of two methods: by reducing the weighted-average GWP (WAGWP) to less than 1,400 GWP, or reducing greenhouse gas potential (GHGp) by 55%. CARB’s proposal could take effect as soon as this January.

R-290 charge limit increases — Recently, the Underwriters Laboratories (UL) approved the second edition of the UL 60335-2-89 standard, which raises the charge limits on commercial self-contained, plug-in displays based on whether they have an open or closed design. For open appliances without doors, the maximum charge limit has been raised to 500g; in closed appliances with doors or drawers, the new charge limit is 300g. These higher charge limits will help original equipment manufacturers (OEMs) to increase system capacities and sizes while capitalizing on R-290’s high efficiency and low GWP. Although additional regulatory approvals and building code updates are needed before these charge increases can fully take effect, this is a critical first step toward wider applicability of R-290.

To support OEMs that develop these self-contained units, Emerson has been producing R-290 compressors and condensing units for many years. Emerson has also been conducting trainings to help contractors and advising OEMs to better understand the new safety considerations for using R-290 to ensure that it can be used safely in these new applications. As manufacturers begin to adopt R-290 systems, they should ensure their systems meet the requirements of UL 60335-2-89 and ASHRAE standard 15.   Today, this portfolio is being updated to accommodate larger charges while expanding into new R-290 qualified products.

New CO2 testing facilities — In addition to Emerson’s CO2 transcritical labs in Europe and at The Helix Innovation Center in Dayton, Ohio, we are currently building new testing labs in our Sidney, Ohio, location. These additions will provide more than 110,000 square feet of engineering and lab space and enable the support of system and component-level testing of CO2 products — including Copeland™ semi-hermetic and scroll compression platforms for CO2 transcritical applications — as well as supporting R-290 and other lower-GWP refrigerant alternatives. In addition, these new test labs will be staffed by dedicated engineering and technician personnel and include testing capabilities for compressors, controls, valves, electronics and supporting components.

To learn more about these policy updates and expanding capabilities, be sure to register for ATMOsphere America’s Online Summit and visit Emerson in our virtual booth.

 

 

 

Natural Refrigerants Remain Viable Among Emerging Options

AndrePatenaude_Blog_Image Andre Patenaude | Director, Food Retail Marketing & Growth Strategy, Cold Chain

Emerson Commercial & Residential Solutions

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.

Safety first

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.

 

Why Contractors Need to Prepare Now for the Coming CO2 Refrigerant Revolution

DonGillis Don Gillis | Technical Training Specialist

Emerson Commercial & Residential Solutions

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

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.

 

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