CO2 transcritical proves more efficient in supermarkets and CVS

After a year of operation, it has been confirmed that the Sprouts Farmers Market, which utilises a transcritical CO2 system in the warm climate of Dunwoody, Georgia, is performing as well as the projected analysis presented in 2014, at 6.3% more efficient than an R407A store. The store utilises an adiabatic condenser/gas cooler to compensate for the higher ambient temperatures.

Harrison Horning, Director of Equipment Purchasing, Maintenance & Energy for Delhaize explained that the company’s natural refrigerant based pilot stores are meant to test the concepts of refrigerating naturally and determine if there is a business case, noting that when there is a business case for these technologies, it is important that retailers invest. According to Horning, there are more CO2 pilots in the pipeline for Delhaize America, including a transcritical store in North Carolina, and its first CO2 TC store is also piloting eight six-foot R290 plug-and-play coffin cases, from which good energy performance is also expected.

Whole Foods is taking charge of responsible refrigeration in the US with pilot stores featuring a variety of natural refrigerant solutions, across the country, including CO2 secondary, cascade and transcritical systems, an ammonia/CO2 system and even propane self-contained units. The energy performances of these different systems were co-presented by Tom Wolgamot, Principal of DC Engineering, and Tristam Coffin of Whole Foods, reporting that the natural refrigerant stores are performing efficiently in many cases. Energy comparisons show the CO2 cascade store outperformed the baseline store and that the transcritical systems’ energy consumption is less than the baseline store.

Kenneth Welter, Senior Manager of Engineering at Baltic Trail Engineering shared Ahold’s experience installing its first CO2 transcritical system. While initial costs of the system were higher than a traditional system, refrigeration and electrical installation costs were actually 7% and 6% less, respectively, compared to the cost of a typical new store.

Paul Bevington, from Carter Group, examined integrated transcritical CO2 refrigeration systems, incorporating refrigeration, heating and air conditioning, installed at convenience stores in both Europe and the United States. The installations have resulted in 50%+ energy reductions.

KAV Consulting’s Klass Visser primarily focused on the possibilities CO2 offers by providing both cooling and heating from the same source, thereby saving considerable energy and significantly reducing greenhouse gas emissions.

Major barriers highlighted include artificially high installation costs due to a lack of training among contractors, though this is steadily improving, and that refrigerant-grade CO2 is not immediately available. Also highlighted is the importance of collaboration among all parties involved in an installation, from OEMs to maintenance partners.

Hydrocarbons gaining traction in commercial refrigeration

Gary Cooper, Director of Refrigeration, Lowe’s Pay and Save, spoke about the company’s experience implementing R290 in a 34,000 ft2 (10,360m2) retail grocery store’s 35 condensing units in Texas. Throughout the entire store, there is a total refrigerant charge of 170oz. According to Cooper, the systems use less power than even those demonstrated in the lab, and 25% less than a traditional system. Cooper noted that a major limitation is the fixed capacity due to charge restraints.

Component suppliers push the limits of CO2

Tommaso Ferrarese examined Carel’s DC waterloop systems in commercial refrigeration and how they offer a new frontier for natural refrigerants. The presentation included the energy efficiency in CO2 systems and the components of DC compressor waterloop systems. Ferrarese concluded with factory-tested units and how they improve the ease of installation, flexibility, and energy efficiency.

Carel also presented in a technomercial its solutions for convenience store applications, in which integration of refrigeration, air conditioning, lighting and energy management are key.

Emerson Climate Technologies’ Reggie O’Donoghue, Director of Product Management, explained the advantages of using electronic controls in CO2 transcritical systems. Electronic controls use algorithms that can optimise the system based on changing environmental conditions, allowing them to manage the complexities of a CO2 TC system as the gas cooler switches between subcritical and supercritical mode.

Don Newlon, VP, Refrigeration Marketing & GM, Integrated Products, presented Emerson’s E360 programme and its Helix Innovation Centre, which are focused on driving innovation through collaboration among all industry stakeholders and encouraging holistic and out-of-the-box thinking. These initiatives are driven by the magnitude of changes facing the refrigeration industry, with particular regard to the quickly evolving regulatory environment and the emergence of electronics and other technological advancements in refrigeration applications. Emerson’s goal is for the industry to work together to find the best combinations to deliver the most cost effective and intelligent systems, keeping in mind that there is no ‘silver bullet’ solution, and to work together on the issues facing the industry in order to solve them.


ATMOsphere America 2015 event website
Presentation – Delhaize America’s experiences with natural refrigerants
Presentation – Whole Foods Market’s world of natural refrigerants
Presentation – The path to transcritical – TC or not TC: that is the question
Presentation – A case study of the CO2 systems in Whole Foods Market Northern California region
Presentation – Integrated CO2 convenience refrigeration installation
Presentation – New alternatives for natural refrigerants in US market: DC compressors waterloop system
Presentation – Case study with a national retailer – comparing calculated energy consumption and actual energy results of a CO2 booster system
Presentation – The advantages of using electronic controls in CO2 booster systems
Presentation – A desktop study into the energy efficiency and environmental benefits of CO2 refrigeration in USA supermarkets

Author Elke Milner