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Selecting Condensing Units for Walk-in Coolers and Freezers

         Don Gillis | Lead Technical Trainer

          Emerson’s Educational Services

Outdoor condensing units (OCUs) have become essential for providing remote refrigeration in the walk-in coolers and freezers (WICFs) used by food retailers, foodservice operators, cold storage facilities and processing plants. As OCU technologies and end-user preferences continue to evolve, contractors need to understand many considerations when selecting an optimal OCU for their specific application and operational requirements. In a recent E360 article, we evaluated key selection criteria and explored today’s leading OCU options.

Sustainability goals, refrigerant regulations and efficiency standards

To help operators comply with environmental regulations and meet their sustainability initiatives, OCU equipment manufacturers are integrating lower-global warming potential (GWP) refrigerants. However, this doesn’t necessarily mean that contractors and end-users will need to adapt to completely new servicing and operating procedures. Many OCUs are designed to use a newer generation of lower-GWP A1 hydrofluorocarbon (HFC) refrigerants — such as R-448A and R-449A — which represent minimal changes in terms of safety protocols or servicing.

But since these lower-GWP A1 refrigerants have degrees of glide, contractors need to be aware of how the sizing and selection process may be impacted. Refrigerants with glide may have a diminishing impact upon system capacity, which might require you to select a slightly larger-horsepower OCU — and unit cooler/evaporator — to meet your refrigeration load requirements.

As safety standards and building codes evolve over the next few years, mildly flammable A2Ls will likely be added to the list of refrigerant alternatives used in OCUs. Today, Emerson is actively qualifying our OCUs for use with A2Ls and will be ready to support operators seeking even lower-GWP A2L options when they are approved.

When it comes to OCU use in WICFs, refrigerants are only part of the sustainability equation. Per the Department of Energy’s (DOE) 2020 rule, WICFs must meet 20–40 percent energy reductions on new and retrofit systems below 3,000 square feet. To calculate the energy efficiency of a complete WICF system, the DOE uses a metric created by the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) called the Annual Walk-In Energy Factor (AWEF).

If you are a contractor installing a condensing unit and/or unit cooler, you must ensure this equipment meets or exceeds the minimum AWEF ratings based on capacity and application — such as medium- (MT) or low-temperature (LT); indoor or outdoor; and refrigerant type. To comply with the DOE standard, simply combine a Copeland™ AWEF-rated condensing unit with an AWEF-rated unit cooler.

Copeland outdoor refrigeration units

Copeland outdoor refrigeration units are designed to comply with regulations and provide sustainable refrigeration for a wide variety of modern operator requirements. Combining the reliable efficiency of Copeland scroll compressor technology with variable speed fans, large condenser coils and smart electronic controls, Copeland X-Line Series outdoor refrigeration units provide whisper-quiet performance in compact enclosures, delivering maximum installation flexibility.

Copeland outdoor refrigeration unit, X-Line Series — available in a horsepower range from ¾ to 6 HP, the X-Line is designed for LT and MT applications, such as WICFs and display cases commonly found in convenience stores (c-stores), restaurants, supermarkets and cold storage facilities. It delivers best-in-class energy efficiencies, a slim profile, ultra-low sound levels, superior diagnostics and built-in compressor protection. Offering AWEF-rated efficiencies and lower-GWP (R-448A and R-449A) refrigerant options, the X-Line supports reliable refrigeration while solving many of today’s operational challenges.

Copeland digital outdoor refrigeration unit, X-Line Series — The digital X-Line Series builds upon the field-proven Copeland scroll and X-Line OCU platforms to deliver superior cooling and energy efficiency in MT applications. Providing variable-speed fan motor control, the digital X-Line Series enables variable-capacity modulation to deliver more precise, reliable refrigeration, longer-lasting equipment and lower energy bills. Available in 3, 4, 5 and 6 HP models, the digital X-Line Series also supports multiplex refrigeration architectures — where one OCU provides cooling for multiple fixtures — to meet a variety of modern refrigeration challenges:

  • Reducing the number of refrigeration fixtures and/or refrigeration loads
  • Precisely sizing refrigeration units and loads to an application
  • Eliminating compressor cycling, which negatively affects system performance and equipment longevity
  • Improving food quality and extending shelf life via tighter temperature control
  • Removing constraints that prevent the installation of multiple fixed-capacity OCUs

Calculate the capacity of your OCU

At Emerson, we are committed to helping contractors calculate refrigeration loads and select OCUs to meet a diverse range of LT and MT refrigeration requirements. By selecting the correct OCUs for your customers’ WICF applications, you can ensure reliable, efficient system performance throughout their lifecycles. To simplify this process, Emerson has created a free online Box Load Calculator tool to assist manufacturers and operators to select, purchase and identify the appropriate equipment for their application. Simply navigate to the Equipment Selection tab, enter your application parameters and estimated refrigeration load, and review your optimal equipment options as you evaluate your specific refrigeration requirements.

Refer to Emerson’s Box Load Calculator to help select a condensing unit for your application.

 

 

 

 

 

 

 

 

 

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.

 

Mobile CO2 Booster Transcritical Training Unit Launches North American Tour

Liborio Mendola Liborio Mendola | Product Planner
Emerson Commercial & Residential Solutions

Emerson’s new CO2 Booster training unit is preparing to make several stops across the U.S. and Canada in 2019. Learn more about what this hands-on experience will offer attendees.

Adoption of the natural refrigerant CO2 (R-744) in commercial and industrial refrigeration applications is on the rise in North America and around the globe. With 0 ozone depletion potential (ODP) and a global warming potential (GWP) of 1, CO2 is considered the environmental standard by which other refrigerants are measured. But with its high operating pressures and unique performance characteristics, industry stakeholders have many questions about how to design, operate and service a CO2 system. That’s why Emerson is pleased to introduce its new, mobile CO2 Booster training unit.

The CO2 training unit is designed to give contractors, manufacturers, wholesalers and end users a hands-on experience and learn what it’s like to work on a CO2 refrigeration system. Launched in Canada in September, the unit has already visited locations in Quebec and trained more than 50 contractors. In early 2019, the unit will travel to the U.S. and make several stops, starting with an appearance in the Atlanta area timed to correspond with the conclusion of the AHR Expo. The current schedule is as follows:

  • January 16–17: Atlanta, Ga.
  • January 30–31: Orlando, Fla.
  • February 13–14: Rancho Cordova, Calif.
  • February 27–28: Elmsford, N.Y.
  • March 20–21: Cudahy, Wis.
  • April 10–11: Brantford, Ont.

Each stop will feature a two-day training session designed to accommodate 20 attendees and cover a wide range of CO2-related topics, including:

  • Subcritical vs. transcritical modes of operation
  • Overview of CO2 system architectures
  • Safe handling, maintenance and charging
  • Startup and shutdown sequences

Become familiar with CO2 and refrigeration system components

The open 360° view of the training unit allows attendees to familiarize themselves with the refrigerant and the components which make up a CO2 system. To demonstrate the volatility of CO2, the unit includes a phase change cell that shows how the refrigerant reacts to pressure changes. Starting in its liquid state, R-744 is subject to increasing pressures and begins its transition into a vapor state, then to a supercritical fluid, until it ultimately becomes a transparent gas. Then, as pressure is dropped within the cell, attendees can see the reverse of this transition as CO2 returns to a liquid state and then forms into a solid piece of dry ice.

The CO2 Booster training unit utilizes a full Emerson system that includes: low- and medium-temperature compressors, electronic controls, protectors, variable-frequency drives and transcritically rated electronic expansion valves. For ease of use, the unit is designed to improve the visibility of all components and dial gauges to demonstrate pressures and temperatures of certain elements.

The transportation container is designed for simplified transport and protection against the rigors of over-the-road travel. This container is also equipped with Emerson’s Cargo Solutions that allow live tracking of the unit’s location, ambient temperature and other conditions through Emerson’s Oversight app.

Registration for scheduled two day sessions is now open. The cost is $700 per person and includes all course materials, breakfast and lunch.

If you’re interested in learning more about CO2, be sure to reserve your spot (Class Title: CO2 Refrigeration) at an upcoming training session.

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