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Posts tagged ‘Commercial Refrigeration’

The Path From IIoT to Predictive Maintenance for Commercial Refrigeration

JohnWallace_Blog_Image John Wallace | Director of Innovation, Retail Solutions

Emerson Commercial & Residential Solutions

Emerson is writing a series of articles about the implications of new and transformative technologies for the commercial refrigeration industry. In our first article, I described the challenges and methodologies related to transforming a newfound wealth of data into true predictive maintenance capabilities. You can read the full article here.


One trend driving the commercial refrigeration industry’s rapid adoption of Industrial Internet of Things (IIoT) technologies is the promise of predictive maintenance. Collecting massive amounts of real-time data comes with the potential to develop data-driven algorithms that can accurately predict looming problems and failures in refrigeration systems and equipment.

In the commercial refrigeration space, operators’ goals related to predictive maintenance are to reduce energy savings, lower maintenance and service costs, improve food quality and safety (and indirectly, customer experiences), increase comfort, and reduce downtime. So as IIoT technologies become more affordable, widely deployed and interconnected, a question naturally arises: “When will we see the results of these predictive maintenance capabilities?”

It’s a fair question. After all, some industries, such as industrial automation, are seeing rapid advances in their predictive maintenance capabilities. But many of these industries also have an inherent advantage: they’re often monitoring identical devices with well-defined historical performance models, making early problem detection relatively easy.

However, commercial refrigeration is a different ballgame. Commercial refrigeration applications are diverse and complex, making the development of their predictive maintenance capabilities far more challenging. Commercial refrigeration systems consist of many diverse and interdependent components, which often originate from multiple vendors. They encompass a wide range from traditional centralized direct expansion systems to an ever-expanding array of emerging architectures designed to achieve very specific operational (and more often, sustainability) objectives. Industry trends further complicate the issue, such as the adoption of new refrigerants and the migration from centralized to distributed, self-contained and integrated systems.

These complex systems differ in the amount, type and quality of the data they can provide — making data modeling and writing algorithms for different equipment even more difficult. Add more variables into the mix, such as weather, humidity and climate — not to mention widely varying operator goals, processes and workflows — and you can start to comprehend the depth of the challenge.

Developing predictive maintenance capabilities for commercial refrigeration is not a matter of simply pouring more data into the cloud via the IIoT. That data is as diverse as the equipment and systems which produce it. Determining the predictive potential of all that data requires fundamentally changing how we understand and approach the needs of the commercial refrigeration industry.

At Emerson, we’re tackling this challenge head on, taking a methodical, deliberate approach to predictive maintenance. Our goal is not to simply throw more IIoT technologies at the challenge. We’re working to help deliver on the promise of predictive maintenance by applying our deep knowledge of the commercial refrigeration space to help operators uncover the predictive value of data gathered from many different applications. By doing so, we’re simplifying the complexities and uncovering insights into the industry’s most common refrigeration scenarios.

We’re deriving predictive maintenance solutions from IIoT data via a three-pronged methodology: 1) understand the complexity of the domain and its individual systems; 2) define what data is relevant to which situations; and 3) determine how application sensors should be used to generate the necessary data. Then we can take the crucial step of developing tools to extrapolate true predictive maintenance answers from real-time and historical data.

In upcoming articles, Emerson will expand on these learnings and provide examples of how new technology is already being used for successful predictive maintenance programs in commercial refrigeration.

Emerson Study Compares CO2 and Hydrocarbon Energy Efficiency in Europe

The study found that those opting for integral R-290 systems could potentially achieve up to €51,000 savings per store on maintenance, energy consumption and refurbishment. The study also points to the ongoing evolution of natural refrigerant technologies and highlights the differences between CO2 and hydrocarbon refrigeration strategies.

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The Rubber Meets the Road

Final rulings signify start of next phase of transition

 For two years, the commercial refrigeration industry has been reeling from a one-two regulatory punch from the Department of Energy and the Environmental Protection Agency. This convergence of aggressive regulations was unprecedented for our industry.


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Dallas E360 Forum Served up Lively Refrigeration Dialogue

Emerson Climate Technologies recently held its fifth E360 Forum on September 3 in Dallas. The event was attended by more than 120 refrigeration industry constituents, ranging from supermarket, restaurant and convenience store end users to trade media representatives, refrigerant providers and original equipment manufacturers. Coming off the heels of the EPA’s final ruling on refrigerant delisting, it was no surprise that the far-reaching regulatory implications — including the DOE’s energy efficiency measures on walk-ins, reach-ins and ice machines — were main topics of conversations.

E360 Forum -Dallas

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CO2 as a Refrigerant — Introduction to Transcritical Operation

This is post number 4 of a series.

Many R744 systems operate above the critical point some or all of the time. This is not a problem; the system merely works differently and is designed with these needs in mind.

  • R744 systems work subcritical when the condensing temperature is below 31 °C (88 °F).
  • R744 systems work transcritical when the gas cooler exit temperature is above 31 °C (88 °F).
  • HFC systems always work subcritical because the condensing temperature never exceeds the critical temperature (e.g., 101 °C / 214 °F in the case of R134a).

The pressure enthalpy chart in Figure 1 shows an example of a simple R744 system operating subcritically at a low ambient temperature and transcritically at a higher ambient temperature. The chart shows that the cooling capacity at the evaporator is significantly less for transcritical operation.

Figure 1: R744 pressure enthalpy chart showing subcritical and transcritical systems

Figure 1: R744 pressure enthalpy chart showing subcritical and transcritical systems

An efficiency drop also occurs with HFC systems when the ambient temperature increases, but the change is not as great as it is with R744 when the change is from sub- to transcritical.

It is important that appropriate control of the high side (gas cooler) pressure is used to optimize the cooling capacity and efficiency when transcritical. For example, increasing the high side pressure will increase the cooling capacity when operating above the critical point.

Behavior in the Reference Cycle

Simple comparisons between R744 and other refrigerants can be misleading because its low critical temperature either leads to differences in system design, such as the use of cascade systems, or to transcritical operation. As a result, like-for-like comparisons are not easy to make.

Theoretical comparisons between R744 and common HFC refrigerants are outlined in the list below.

  • R744 compares reasonably well with HFC systems when subcritical and at low condensing temperatures. But the comparison is less favorable at higher condensing temperatures and when transcritical.
  • The high suction pressure and high gas density of R744 results in very good evaporator performance. In like-for-like systems the evaporator temperature of an R744 system would, in reality, be higher than for an HFC equivalent.
  • The index of compression is very high for R744, so the discharge temperature is higher than for the HFCs. This can improve heat reclamation potential in retail systems, although the requirement for heat in the summer when the system is transcritical is limited.
  • The density of R744 results in very high volumetric capacity. This reduces the required compressor displacement, but not the motor size, which would be similar to that required for HFC refrigerants.
  • The required suction pipe cross-section area is in proportion to the volumetric capacity. For R744 the diameter of the suction line is approximately half that required for R404A.
  • The compression ratio for R744 is less than for HFCs. This can result in higher isentropic efficiency.

Upcoming CO2 as a Refrigerant series topics will cover the potential hazards of R744, compare it to other refrigerants (both traditional and new), and weigh its advantages and disadvantages as a refrigerant.

Andre Patenaude
Director – CO2 Business Development, Emerson Climate Technologies

Visit our website for additional information on CO2 Solutions from Emerson. 
Excerpt from original document; Commercial CO2 Refrigeration Systems, Guide for Subcritical and Transcritical CO2 Applications.

To read all posts in our series on CO2 as a Refrigerant, click on the links below:

  1. Series Introduction
  2. Criteria for Choosing Refrigerants
  3. Properties of R744
  4. Introduction to Trancritical Operation
  5. Five Potential Hazards of R744
  6. Comparison of R744 with Other Refrigerants
  7. R744 Advantages / Disadvantages
  8. Introduction to R744 Systems
  9. Introduction to Retail Transcritical Systems
  10. Retail Booster Systems
  11. Introduction to Retail Cascade Systems
  12. Introduction to Secondary Systems
  13. Selecting the Best System


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