Southeastern U.S. retailer Publix Super Markets plans to install transcritical CO2 (R744) refrigeration in five new stores opening between August and December, adding to the three new stores already equipped with a transcritical CO2 system.
In addition, in September Publix will replace an HFC-based system with a transcritical CO2 system at an existing store in the Atlanta, Georgia, area – the chain’s first CO2 retrofit project. All of the transcritical CO2 systems for the new stores and retrofit are supplied by Conyers, Georgia-based manufacturer Hillphoenix, part of Dover Food Retail.
Publix’s plans were presented by Doug Milu, Refrigeration and Energy Program Manager for the Lakeland, Florida-based chain, and Derek Gosselin, Director of Technical Product Support, Hillphoenix during a Refrigeration Case Studies session at the ATMOsphere (ATMO) America Summit 2022 on natural refrigerants. The conference, which took place June 7-8 in Alexandria, Virginia, was organized by ATMOsphere (formerly shecco), publisher of R744.com.
While the new stores will all be equipped with two “dual-suction” (medium and low temperature) Advansor rack systems, the retrofit store will have three dual-suction AdvansorFlex-Mini racks – Hillphoenix’s smallest CO2 rack system – on the roof. The three racks will provide redundancy, Milu noted.
The retrofit will be rolled out in stages to keep the store open – the biggest challenge with retrofits, said Milu.
This retrofit installation will be used to gain operational experience, with Milu stating that “if it succeeds, it will become the standard” for the chain’s existing 1,300 stores. According to Milu, Publix changes out the rack system in 10-12 stores per year.
Publix’s next new store to use a transcritical CO2 system will open August 3 in Chamblee, Georgia, followed by new transcritical CO2 stores in St. Augustine, Florida (August 6); Auburn, Alabama (September 7); Pembroke Pines, Florida (September 22); and Neptune Beach, Florida (December 8).
Publix installed its first transcritical CO2 system at a new store in Longwood, Florida, opened in June 2020, and its second at a new store in Tampa, Florida, opened in August 2021. A third new transcritical CO2 store opened in November 2021 in Chattanooga, Tennessee.
In addition to the Hillphoenix racks installed at Publix’s CO2-based stores, display cases come from a variety of providers, including Hillphoenix, Zero Zone, Structural Concepts and Southern CaseArts.
Energy parity achieved
As detailed in Milu’s presentation, CO2 has many benefits as a refrigerant including being a natural product with a GWP of one, achieving energy parity with HFC-based systems, and offering high-quality heat reclaim opportunities. Publix also views CO2 as a future-proof solution due to little threat of becoming regulated.
“Our position is not just about what we’re managing today, but what we’re looking at for 15 and 20 years into the future,” said Milu. “We believe that transcritical CO2 is the future for Publix.”
“We believe that transcritical CO2 is the future for Publix.”Doug Milu, Publix
Publix began using CO2 as a working refrigeration fluid 11 years ago at a store in Conyers, Georgia, in a R407/CO2 cascade system. In July 2019, the chain opened its first store with DX CO2 for low-temperature cases and liquid CO2 overfeed, linked to a small R449A topside system, for medium-temperature cases.
According to Milu, Publix now has around 100 stores using CO2 as a refrigerant in some capacity.
Publix has supermarkets based across seven southeastern states in the U.S., where ambient temperatures are higher on average. In this climate, transcritical CO2 systems need additional equipment to maintain their efficiency.
As detailed by Gosselin, adiabatic gas coolers offer a “warm-weather solution.” Other important technologies that could help improve efficiency in all climates include sub-cooling, parallel compression, gas/liquid ejectors and pressure exchangers.
Both Milu and Gosselin emphasized the need for retailers and suppliers to work closely together to “create an environmentally sustainable refrigeration solution for store operations.”
This includes addressing the CO2 training challenge, for which Hillphoenix has a Learning Center at its Conyers, Georgia, headquarters while Publix has an in-house training facility.
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