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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.










Recruiting the Next Generation of HVACR Professionals

RajanRajendran2 Rajan Rajendran | Global Vice President, Environmental Sustainability

Emerson’s Commercial & Residential Solutions Business

The growing shortage of qualified HVACR service technicians is perhaps the greatest challenge facing the commercial refrigeration industry today. As we transition to lower-global warming potential (GWP) refrigerant technologies and system architectures, the collective role of our technician workforce will be more essential than ever. I recently explored ways to reverse this trend in an article published in HVACR Business.

Industry statistics reveal the urgency of the current situation:

  • 80,000 HVACR technician jobs are currently unfilled — representing 39 percent of the total industry workforce.
  • An estimated 20,000 technician jobs are lost annually due to the retirement of an aging workforce or career attrition rates.

For years, Emerson has been a champion of shoring up the technician workforce by collaborating with vocational schools, helping to shape curriculum and supporting students along their HVACR career journeys. But solving this problem will require the participation of all industry stakeholders — from contracting companies, manufacturers, end-users, wholesalers and trade associations to educators, adjacent industries and government agencies.

Engage locally

Stakeholders agree that one of the most effective strategies for recruiting the next generation of HVACR technicians is by supporting local vocational schools and technical colleges. Combined with incentives from state governance, industry-sponsored scholarship programs and pre-apprenticeship opportunities, this local approach can inspire a lifelong passion for HVACR careers.

We’ve seen examples of this local engagement model firsthand. Emerson’s The Helix Innovation Center often interacts with students enrolled in nearby vocational schools here in Ohio. We recently offered a pre-apprenticeship opportunity to Nicholas Didier, a student attending the Miami Valley Career Technology Center (MVCTC) near Dayton.

As a high school senior enrolled in an HVAC program, Didier was interested in learning more about the basics of refrigeration and getting hands-on field experience. During his time at The Helix, he gained a much more in-depth understanding of the challenges facing our industry, a greater appreciation of the service profession and a passion for system design.

Nicholas’ efforts were recognized by the Ohio Valley chapter of the Associated Builders and Contractors (ABC), who awarded him a new Ford Ranger truck and a $1,000 scholarship via its Today’s Opportunities Offering Lifetime Skills (TOOLS) program. He plans on using these funds to purchase HVACR technician tools and further his education.

Changing perceptions

Industry stakeholders attribute the declining interest in HVACR roles to a variety of misperceptions and an overall devaluing of trade professions. One primary example is the belief that HVACR professionals do not make a competitive wage or have long-term career path opportunities.

Social media streams — which often present unrealistic, idealized views of the four-year college experience and other professions — make it even more difficult to change these perceptions.

But upon closer inspection, these myths easily can be dispelled. HVACR technician jobs check important boxes for many young professionals that four-year college degrees simply cannot.

  • Make an impact with a meaningful career —HVACR professionals are implementing new environmentally-friendly solutions and technologies that will play an integral role in greening our planet.
  • Work with cutting-edge tools and technologies —Modern refrigeration and AC applications utilize advanced controls, software and remote diagnostics capabilities.
  • Achieve job security —With little competition for available jobs, HVACR professionals are virtually guaranteed employment and enter a field with both long-term security and growth potential.
  • Earn while you learn — HVACR technicians can earn a competitive wage with a two-year vocational certification and have the option to augment the certification process with on-the-job training in apprenticeship programs.

It’s important for all industry stakeholders to understand, highlight and promote these differentiating factors to help paint a more realistic — and positive — picture of modern HVACR professions. At Emerson, we will continue to reach out to local vocational schools and technical colleges to hopefully guide more students along this path.


STEM Day Brings Emerson’s Yearlong Efforts Into Focus

Ken Monnier | Chief Technology Officer,

Emerson’s Commercial and Residential Solution’s Business

November 8 is Science, Technology, Engineering, Art and Math (STEM/STEAM) Day — a time when the nation pauses to recognize the importance of these disciplines within our educational curricula. At Emerson, we are committed to supporting STEM initiatives year-round, and STEM Day allows us to reflect on the year’s activities and plan for what’s to come. In a historically male-dominated industry, it’s particularly important for Emerson to celebrate the contributions of women in our organization and create an environment where they can thrive and succeed. Let’s look at some of the ways we’re leveraging STEM initiatives to help create the next generation of engineers and support the increased inclusion of women within our industry.

Women in STEM (WiS) program charter and achievements

Emerson created its global WiS program to attract, develop and retain the top women candidates in STEM-related roles, enhance the diversity of ideas and approaches for the benefit of our customers, and fully deliver on our “Consider It Solved” promise. The program supports generations of women in all stages of their careers, from schoolchildren who are just beginning to think of their futures to professionals and senior executives who are navigating their career paths.

Based on some of the metrics gathered, we are well on our way to achieving the goals of this charter.

  • Membership increased to more than 5,000 global members
  • STEM-related webinar event attendance increased by 60%
  • Local chapter (Sidney, Ohio) membership increased by 10%
  • Launched a new global WiS SharePoint site
  • Ranked as #12 on Women Engineer Magazine’s list of top companies to work for
  • Awarded Gold, Best Practice Outreach and Best Practice Professional Partnerships by the Society of Women Engineers (SWE)

These achievements are indicative of the three guiding principles of our WiS program:

  1. Attract and inspire young girls to pursue STEM subjects and careers while recruiting top STEM female candidates to work at Emerson
  2. Provide opportunities to develop leadership skills and elevate the visibility for women in STEM-related roles
  3. Create an inclusive, connected community where women in STEM feel supported and have a sense of belonging throughout Emerson; provide a platform to highlight women in STEM as role models across Emerson

Emerson’s WiS program enables us to facilitate community outreach throughout our global offices and places of business. For example, the local WiS chapter in our Sidney, Ohio, location includes more than 100 members comprised not only of Sidney branch employees, but also extending out into other local manufacturing and engineering-related companies.

Ongoing commitment to STEM education, activities and events

Even though the past two years have made it difficult to plan and host in-person, STEM-related events, Emerson has continued to develop a series of educational webinars and promotional activities focused on professional development, social networking and STEM outreach to schools and universities. These activities include:

  • Sponsoring a cardboard boat race during the Summer Olympics
  • Celebrating Pi Day with pi-inspired games and the distribution of moon pies
  • Hosting a WiS online trivia event
  • Conducting educational webinars with prominent female executives and keynote speakers

Collectively, these achievements, educational events and promotional activities represent our ongoing commitment to furthering STEM careers and related disciplines — within Emerson and the global workforce. Emerson’s ongoing WiS efforts are having a direct impact on our business, transforming our culture and infusing it with fresh perspectives and insights that make us a more well-rounded and successful organization.


Refrigeration Basics: Addressing the HVACR Technician Shortage

         Don Gillis | Lead Technical Trainer

          Emerson’s Educational Services

Welcome to the fifth and final installment in our blog series intended to help not just beginning service technicians, but anyone who wants to learn more about the basics of refrigeration. In this blog, I explain what we at Emerson and others are doing about the growing shortage of skilled, qualified and certified HVACR technicians in the industry. For this series, we’ve also created companion videos about each topic that you can cross-reference while accessing other related information at

Nearly 40 percent of the jobs available in the HVACR industry are unfilled. That’s about 80,000 good-paying positions for technicians who can install, maintain and repair the critical refrigeration equipment upon which our customers depend. At the same time, our industry loses experienced technicians as aging workers retire and also as the result of normal attrition every year. If we do not hire and train new technicians, our industry could potentially face a deficit of 100,000 workers within the next five years.[i]

That’s one of the reasons I’ve written this series of blogs about refrigeration basics. With the help of others at Emerson, I’ve also created a related set of videos to explain what refrigeration technicians do — and what they must know to be successful in our business. We need more skilled, qualified and certified HVACR technicians. So we’re promoting our educational services, which include instructor-led and online courses.

Emerson also partners with industry organizations and leaders to create learning opportunities through events such as World Refrigeration Day. To mark that day in June, we shared a webinar, Exploring Cool Careers and Emerging Opportunities in HVACR, which showed how refrigeration technicians have a high earning potential and work with advanced technologies and modern tools. You can watch the webinar on-demand.

Young people should consider a career in HVCAR because they can:[ii]

  • Make an impact — Refrigeration technicians implement new environmentally friendly solutions that will play an integral role in making the world a better place to live.
  • Work with cutting-edge tools and technologies — Modern refrigeration and air conditioning applications utilize advanced controls, software and remote diagnostics capabilities.
  • Achieve job security — With little competition for available jobs, HVACR professionals are virtually guaranteed employment and will enter into a field with both long-term security and growth potential.
  • Earn while they learn — HVACR technicians can earn a competitive wage with a two-year vocational certification and have the option to augment the certification process with on-the-job training in apprenticeship programs.

At Emerson, we are committed to recruiting the next generation of HVACR technicians. Our company is addressing the technician gap in three ways by:

  1. Offering courses for upcoming technicians so that they can expand their knowledge of HVACR fundamentals
  2. Recruiting the next generation of HVACR technicians by providing real-life experiences through co-ops and internships
  3. Partnering with industry leaders so that we can brainstorm ways to bridge this gap

The reality is that there’s an abundance of lucrative opportunities for young people who want a long-term career path without the time commitment and cost of a four-year college education. That’s why I’m really excited about the future of the refrigeration industry. Indeed, jobs and training are available to enable people to acquire the necessary refrigeration skills. Emerson is helping in that regard, too. If you’re interested, let’s talk.


Read “Reversing the Trend: Recruiting the Next Generation of HVACR Professionals ” to discover how Emerson is working to make refrigeration technician careers ‘cool’ again.




[i] Rajan Rajendran, “Become a “Cooling Champion” for World Refrigeration Day 2021,” June 26, 2021, Emerson Climate Conversations, (accessed July 20, 2021).


[ii] Rajan Rajendran, “Reversing the Trend: Recruiting the Next Generation of HVACR Professionals,” E360 Outlook, June 2021, (accessed July 20, 2021).



Refrigeration Basics: Understanding the Refrigeration Cycle

         Don Gillis | Lead Technical Trainer

          Emerson’s Educational Services

Welcome to the fourth installment in our series of blogs intended to help not just beginning service technicians, but anyone who wants to learn more about the basics of refrigeration. In this blog, I explain the nuances of vapor injection along with the full refrigeration cycle. For this blog series, we have also created companion videos about each topic that you can cross-reference while accessing related information at

Comparing Refrigeration to a Baseball Diamond

The refrigeration cycle requires four main components. No matter how small or how large a cooling system might be, its design will include a compressor, a condenser, a metering device and an evaporator.

When I teach new technicians, I often compare the refrigeration cycle to the layout of the field for the game of baseball. I’ve found this analogy makes refrigeration equipment and processes easier for them to understand.












In my example, a compressor is located at home plate at the bottom of the baseball diamond (shown above). In a refrigeration or cooling system, compression is the first step:

  • Refrigerant enters as a low-pressure (LP), low-temperature (LT) superheated vapor and exits the compressor as a high-pressure (HP), high-temperature (HT) vapor.
  • The compressor mechanically compresses the refrigerant gas.
  • Under pressure, the refrigerant volume is reduced and the temperature is raised.

The second step involves a condenser, located at first base on the right side of the baseball diamond:

  • Hot, pressurized refrigerant gas arrives from the compressor into the condenser, which is designed to reject heat by lowering or returning the temperature of the refrigerant to its condensing temperature.
  • As it rejects heat, the condenser converts the vapor to a sub-cooled liquid.
  • In most condensers, the refrigerant gas enters at the top of the equipment and leaves at the bottom because the refrigerant in a liquid state is much heavier than the weight of refrigerant in a gas state.

In the third step, a metering device located at second base at the top of the baseball diamond regulates the amount of refrigerant released into the evaporator in response to the cooling load and causes a pressure drop.

The metering device also:

  • Measures the superheat at the evaporator outlet
  • Maintains a constant temperature by raising or lowering the amount of refrigerant flowing into the evaporator

At the fourth step, cold liquid refrigerant mixes with vapor causing the saturation temperature as it boils off or vaporizes in the evaporator, located at third base, on the left side of the baseball diamond:

  • The process allows the refrigerant to absorb heat through a series of metal coils.
  • The low-pressure superheated vapor refrigerant gas then returns to the compressor to continue the refrigeration process.

Here is the value of comparing the refrigeration process to a baseball diamond: If I draw a vertical line from home plate up to second base, everything in the system on the right side of that line is under high pressure; everything on the left side of that line is low pressure.

Likewise, if I draw a horizontal line from first base to third base, the refrigerant above the line is in a liquid state; below the line, the refrigerant is a vapor, regardless of whether it is under high or low pressure.

Liquid Injection Cools Compressor and Increases Capacity

A compressor is designed to operate at very high temperatures, so a liquid injection method has been developed to cool the compressor internally. How this works can be confusing; refrigerant is injected in a vapor state, not in a liquid state.

When necessary, liquid injection cools a compressor to enable it to run reliably under difficult high compression ratio conditions normally seen on low-temperature freezer applications.

  • Refrigerant is piped from the system liquid line, through an injector valve to the compressor; in scroll compressors, the refrigerant is injected directly into the scroll elements.
  • Without this cooling, the compression elements can get too hot and the oil breaks down, leading to compressor failures.

Another approach called enhanced vapor injection (EVI) increases refrigeration capacity and, in turn, the efficiency of the system:

  • A heat exchanger is utilized to provide subcooling to the refrigerant before it enters the evaporator.
  • A small amount of refrigerant is evaporated and superheated above its boiling point.
  • This superheated refrigerant is then injected mid-cycle into the scroll compressor and compressed to discharge pressure.

The diagram below shows how enhanced vapor injection (EVI) increases the efficiency of the system.










EVI increases the compression ratio and, in the process, boosts capacity for the refrigeration system. The greatest gains can be achieved during the summer months and other periods when warm ambient temperatures require more cooling.

View our new video series to learn more about the refrigeration cycle. For a deeper dive into all of our training content and access to our other educational resources, visit

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