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CO2 as a Refrigerant — Series Introduction

CO2 offers refrigeration with low global warming impact, but with new application and handling considerations

Weighing up natural refrigerant alternatives

This is post number 1 of a series.

Commercial refrigeration has been in the environmental spotlight for more than a decade, especially as leakage studies have revealed the true effects of hydrofluorocarbon (HFC) emissions. Considerable reductions in emissions are possible, but implementing them is having a major impact on the refrigeration industry. In response, many new refrigerant options and system architectures have appeared — both on paper and in practice — creating tricky choices for decision makers in commercial refrigeration.

The significant environmental advantages of R744 (CO2) have guaranteed its position as a leading option for future refrigeration systems. It has demonstrated favorable results in different system configurations over many years, particularly in Europe, Australia and Canada. Initially high investment costs are now on a downward trend, while innovations in component technology and application methods continue to reveal potential performance gains. These results have ensured that CO2 will be a long-term option in the foreseeable future.

This post is the first in a series that will introduce CO2 as a refrigerant. The blog series will summarize the properties of R744 and examine how well it meets traditional and emerging needs for refrigerants. The series will also covers some of the reasons why CO2 refrigeration systems differ from conventional systems, notably the design considerations created by the need for transcritical operation under certain conditions. Other topics concerning R744 will also be examined, including the general aspects of R744 systems; more detailed information about the design of R744 cascade, transcritical booster and secondary systems; and key points about their commissioning, operation and service.

In the next post I will discuss the basics and considerations in criteria for choosing refrigerants. Multiple factors need to be carefully considered and we’ll take a look at how well R744 meets key criteria.

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


4 Comments Post a comment
  1. Laird Heinz #

    Is Emerson looking into larger compressor use for R744 ? ie Vilter screw and recip ? I believe cold storage use of R744 and R717 in the mechanical room would be great ! I have seen this in Japan in an ice block facility.

    April 7, 2016
    • Laird
      Thank for your question.
      Your are absolutely right. Growing Trends within the industrial refrigeration space from low charge ammonia DX systems, to removal of ammonia from occupied spaces and the increased popularity of using CO2 as a volatile brine and as a direct expansion refrigerant has cause manufacturers like EMERSON to carefully evaluate product needs.
      In the next several months Emerson will be launching a number of new large capacity compressors for CO2.
      First off we will launching our 4MTL(S) line of transcrirical compressors in 35, 40 and 50HP range. This will definitely help system designer tasked with building large capacity systems.
      We are also preparing to launch large capacity subcritical Low Temp line of industrial open drive recips. The 550 series will be initially launched in 50 and 200 ton models. At the end of next year we will add the 100 and 150 ton models.
      I hope this answers your question.

      August 23, 2016

Trackbacks & Pingbacks

  1. Carbon Dioxide: The future for a Cooler World - Principia Scientific International
  2. R-744 Carbon Dioxide Refrigerant Fact & Info Sheet - Refrigerant HQ

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