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Posts tagged ‘Andre Patenaude’

Blog 10: The Convergence of Ammonia/CO2 Technologies

AndrePatenaude_Blog_Image Andre Patenaude | Director Food Retail, Growth Strategy

Emerson Commercial & Residential Solutions

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In my previous blog, I explained why CO2 and ammonia (aka NH3) refrigerant technologies are crossing over into each other’s traditional market spaces, i.e., CO2 making its way into industrial settings and low-charge ammonia systems in use in commercial applications.

As regulatory compliance concerns and sustainability objectives drive end users toward natural refrigerants, original equipment manufacturers (OEMs) are responding with new innovations that draw from traditional CO2 and ammonia architectures.

Let’s look at some innovations that are indicative of this convergence.

NH3/CO2 cascade — Ammonia in commercial refrigeration

Owners of large (+100-ton) commercial HFC systems are now considering implementing smaller, lower-charge NH3/CO2 cascade systems. In turn, some industrial OEMs are expanding their product portfolios to target the emerging niche for natural, energy-efficient systems in commercial refrigeration. These NH3/CO2 cascade systems are designed to operate with very low charges of ammonia (100 pounds or less) on the high side of the refrigeration cycle (in a remote location, e.g., the roof) to chill the CO2 sent out to the cases in a store.

CO2 transcritical booster — CO2 in industrial refrigeration

CO2 offers a documentation-free refrigeration alternative to long-time operators of large-charge ammonia systems. Commercial OEMs with CO2 expertise are answering the call for CO2 transcritical booster systems, which have proved viable in cooler regions. This system utilizes several compressors in parallel to meet the desired cooling requirement. CO2 blast freezers are also effective in low temperatures, especially below -40 °F.

Smaller-platform applications for ammonia

Both commercial and industrial operators with smaller facilities have a variety of low-charge ammonia options from which to choose to meet their cooling requirements and sustainability goals:

  • NH3 low-charge centralized — this remote, distributed architecture is designed to reduce the liquid line length and subsequent refrigerant charge.
  • NH3 direct expansion — available in distributed or remote varieties, this system requires the circulation of much less refrigerant.
  • NH3 chiller with pumped CO2 secondary — ammonia chills CO2 (volatile brine), which is then pumped into the refrigerated areas.
  • NH3 chiller with pumped CO2 secondary, plus CO2 cascade — combines an NH3 chiller that provides the medium-temperature load via a CO2 secondary design, plus a CO2 cascade system for the low-temperature side.

This convergence also proves that operators of commercial and industrial facilities have more in common than they realize. Both are trying to balance capital expenditures, total cost of ownership and sustainability objectives in their selection of refrigeration systems. So, the blurring of lines between CO2 and ammonia technologies in these markets is ultimately beneficial to all involved.

Read the full Accelerate America article on the convergence of ammonia and CO2 technologies [pg.16].

Blog 9: Why CO2 and Ammonia Are Trading Places

AndrePatenaude_Blog_Image Andre Patenaude | Director Food Retail, Growth Strategy

Emerson Commercial & Residential Solutions

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CO2 and ammonia (aka NH3) are two natural refrigerants that have historically played predictable roles in refrigeration. Ammonia has long been considered a workhorse in low-temperature, industrial refrigeration. More recently, CO2 has emerged as a leading alternative to hydrofluorocarbon (HFC) refrigerants, especially in commercial applications. Just as we became accustomed to their familiar roles, manufacturers are developing new refrigeration technologies that blur the lines between these traditional applications.

Driven by sustainability objectives and regulatory compliance, these natural refrigerant technologies are converging into competing market spaces — where CO2 is becoming a viable option in industrial applications and low-charge ammonia systems are making inroads into commercial applications.

CO2 has the global HFC phase-down to thank for gaining a foothold in commercial refrigeration. With near-zero global warming potential (GWP), it is one of the few ultra-low GWP refrigerants to be listed as acceptable by the Environmental Protection Agency’s Significant New Alternatives Policy. CO2 also has minimal safety or toxicity barriers to adoption with respect to building and fire codes.

On the other hand, ammonia has been the subject of increasing regulatory activity to address its potential toxicity concerns. The Occupational Safety and Health Administration (OSHA) requires operators to provide documentation for systems charged with at least 10,000 pounds of ammonia.

Operators of these large-charge systems, which are typically found in industrial applications, must be prepared for rigorous inspections enforced by OSHA’s National Emphasis Program (NEP) on process safety management industries.

To mitigate safety and compliance concerns, a trend is emerging that favors lower-charge ammonia systems and moving the NH3 portion out of occupied spaces. This is enabling these systems to be deployed not only in industrial settings, but also in commercial applications. Likewise, adaptations of common CO2 architectures are making their way into what have historically been ammonia-based, industrial applications.

Regardless of potential installation caveats or market segment, many end users are primarily motivated by the desire to leave a smaller carbon footprint. Natural refrigerants like CO2 and ammonia are helping them meet this objective through the deployment of low-GWP, energy-efficient systems.

That’s why both commercial and industrial operators are turning to original equipment manufacturers (OEMs) to explore the potential of these natural refrigerant options. In turn, OEMs are responding with new innovations and system technologies that borrow from traditional architectures and cross over into competing market spaces.

In my next blog, I’ll look at some innovations that are indicative of this convergence.

Read the full Accelerate America article on the roles of CO2 and ammonia [pg.16].

Blog 8: CO2 System Architectures: Opportunities in Food Retail

AndrePatenaude_Blog_Image Andre Patenaude | Director Food Retail, Growth Strategy

Emerson Commercial & Residential Solutions

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Food retailers seeking to make the move to CO2 refrigeration have two primary system types from which to choose: CO2 transcritical booster and cascade systems. A closer look at each option may help you decide which is a better fit for your operations.

CO2 transcritical booster

A complete R-744 system, CO2 transcritical booster utilizes direct expansion (DX) for low- and medium-temperature suction groups. This system is called transcritical because it is designed to operate at pressures above CO2’s critical pressure (1,500 psig). Heat produced from low-temperature case compressors is rejected into the medium-temperature suction group’s compressors. The medium-temperature compressors are the workhorses of the system and must be sized to handle:

  • The total heat of rejection of low-temperature loads
  • 100 percent of the medium-temperature load
  • The flash tank bypass load

Only one condenser or gas cooler is needed for all low- and medium-temperature cases. CO2 pumped technology — where CO2 is used as a secondary fluid — is also available on both low- and medium-temperature stages.

CO2 cascade

CO2 cascade systems utilize two distinct refrigeration circuits: a CO2 circuit for the low-temperature suction group, and an HFC-based circuit (such as HFC-134a) for the medium-temperature needs. It’s called cascade because the heat produced from the low-temperature circuit is discharged into the suction stage of the medium-temperature circuit via an intermediate heat exchanger. Medium-temperature compressors send gas to an air-cooled condenser on the roof. Like a standard refrigerant, CO2 is maintained below its critical point (or subcritical mode) of 88 °F.

For an all-natural cascade alternative, some retailers have even experimented with using NH3 (ammonia) as the medium-temperature refrigerant. These low-charge ammonia circuits are typically housed on the facility roof, far removed from the store’s occupied spaces.

Evolution of electronics

Unlike traditional HFC systems, CO2 system architectures introduce the requirement for additional electronic components, including: case controllers, pressure transducers, temperature sensors and electronic expansion valves. While these components may contribute to increased system costs, they’re necessary for optimizing the refrigerant quality and pressures to the cases. From an end user and servicing perspective, these case controllers provide quick access to precise temperature controls and ongoing, optimized energy efficiencies.

The benefits of going green

For those U.S. retailers who have experimented with CO2 refrigeration, the benefits are obvious. New Seasons is a Northwestern grocer whose first CO2 system earned a GreenChill Platinum Certification award for green refrigeration. Their CO2 transcritical booster system delivered the following improvements:

  • Up to 30 percent lower total equivalent warming impacts (TEWI)
  • 95 percent fewer refrigerant emissions
  • Smaller refrigeration footprint

The retailer is currently planning additional CO2 installations.

  1., pg. 3

Read the full Accelerate America article on CO2 system architectures [pg.16].

Blog 7: CO2 Leaves a Smaller Carbon Footprint in Large-Format Food Retail Market

AndrePatenaude_Blog_Image Andre Patenaude | Director Food Retail, Growth Strategy

Emerson Commercial & Residential Solutions


Market drivers and refrigerant regulations in recent years have placed an increased focus on sustainability for large-format retailers. Among the natural refrigerant alternatives suitable for these centralized applications, CO2 (or refrigerant name R-744) leads the pack. Offering zero ozone depletion potential (ODP) and a global warming potential (GWP) of 1, CO2 is often considered the benchmark for environmentally friendly refrigerants. In terms of customer-facing peace of mind, CO2 has neither the flammability nor toxicity challenges posed by other natural refrigerant alternatives. And, as energy efficiencies and the reliability of CO2 refrigeration systems rise, system costs have fallen to levels typically found in traditional hydrofluorocarbon (HFC) systems.

Increasing global CO2 adoption

For all these reasons, CO2 has become the preferred natural refrigerant option for large-format food retailers. A recent Shecco study1 on CO2 adoption confirms this trend, showing a growing number of CO2 transcritical stores worldwide:

  • Canada: 150+
  • United States: 260+
  • Japan: 2,400+
  • Europe: 9,000

The number of CO2 stores in the E.U., Norway and Switzerland has tripled in the last three years, representing 8 percent of the overall food retail market share in these regions. In North America, retailers are still in an experimental “trial” phase to see how CO2 — and other natural refrigerants for that matter — can be used in their facilities and across varying climatic zones.

As older systems age and require upgrading or replacement, many large-format food retailers will be seizing the opportunity to transition from higher-GWP, HFC refrigeration architectures to lower-GWP systems. This trend toward eco-friendly refrigeration is being driven by multiple forces: 1) global regulatory efforts to phase down HFCs; 2) industry organizations like the Consumer Goods Forum that advocate the use of these systems; and 3) many retailers are stating corporate sustainability objectives.

Economies of scale reduce operating costs

The steady increase in global CO2 refrigeration adoption has led equipment and component manufacturers to not only increase production, but also make continued investments in research and development to refine CO2 technologies. These economies of scale are helping to lower CO2 system costs and reduce complexities for end users and service technicians alike.

CO2 training — both formal and hands-on types — has greatly improved as the industry becomes much more familiar with CO2 architectures and performance characteristics. Even refrigeration consultants are becoming well-versed in CO2 systems and can make more educated recommendations.

While the U.S. is still in the early phases of trials and experimentation, every successful implementation increases the likelihood of more stores making the transition to CO2. Safe, environmentally friendly, economical and reliable: CO2 has all the characteristics that make it a candidate as the large-format refrigerant of the future.

Read the full Accelerate America article on the large-format refrigerant of the future [pg.16].

[Webinar Recap] Factors in Evaluating and Selecting Refrigerants

AndrePatenaude_Blog_Image Andre Patenaude | Director Food Retail, Growth Strategy

Emerson Commercial & Residential Solutions

This blog is based on our most recent E360 Webinar, “Top Retailer Trends for Refrigeration, Controls and Facility Optimization.”


I recently participated in an E360 webinar where we explored trends in refrigeration systems and controls and discussed how they continue to evolve to keep up with changes in consumer preferences, global regulations and market dynamics. The webinar also featured John Wallace, Emerson’s director of innovation, and Andrew Knight, vice president of Henderson Engineers. Together, we presented insights into the factors driving refrigerant selection, controls architectures and design strategies.

The first of these trends is the continuing global transition toward the use of more environmentally friendly refrigerants. When we look at the market dynamics behind this movement, refrigerant selection is one factor among a long list of considerations for food retailers — but one that impacts system architectures, controls and long-term operational goals.

It’s important to keep in mind that food retailers are making refrigerant decisions within an increasingly complex cold chain. As the product journey from farm to fork requires many handling and transportation steps involving multiple intermediaries, the objective of maintaining consistent temperature remains paramount. But, once food arrives in their stores, retailers then face a combination of consumer-driven and operational requirements, including:

  • Producing consistently fresh, high-quality foods
  • Appealing to the growing demand for “experiential retail”
  • Meeting energy efficiency and sustainability objectives

As a result, retailers are making investments in improved shopping experiences, new refrigeration systems and facility management controls.

Natural Refrigerant Architectures

The current regulatory climate has paved the way for the resurgence of natural refrigerants — largely due to their ultra-low global warming and ozone depletion potentials. Commercial and industrial refrigeration manufacturers continue to develop systems that utilize the potential of these gases while mitigating their operating challenges. Among the leading natural refrigerant architectures used in supermarkets are:

  • CO2 booster transcritical — large-capacity system based completely on CO2; ideal for low ambient conditions; high ambient strategies are becoming more viable
  • Indirect chiller with cascade — niche application delivers a fully natural solution for large commercial or industrial applications; capable of utilizing multiple, low-charge refrigerant options, including: naturals, HFOs or A2Ls
  • Distributed — well-suited for smaller applications; allows for multiple refrigerant options (including CO2) and the flexibility to deploy individual systems for low- and medium-temperature suction groups
  • Integrated case (or micro-distributed) — integrates the refrigeration system into the case, typically using a low charge of R-290 (propane); unit condensers connect to a shared water loop for heat management

In our next blog, John Wallace will discuss the crucial role of controls in these systems and how refrigerants influence controls architectures.

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