Leading U.K.-based grocery retailer Tesco has installed transcritical CO2 systems at about 1,000 stores, or about one-third of its food outlets, with plans to be HFC-free chain-wide by 2035.
That update was provided by Philipp Holzer, Tesco’s Refrigeration Engineering Manager, Property – UK & Group Energy Engineering, during an interview at an ATMOsphere Network event in the booth of German OEM TEKO at the Chillventa trade show last week.
“Six years ago we decided all new [refrigeration] systems would be CO2,” said Holzer, who took questions from Marc Chasserot, CEO of ATMOsphere, publisher of R744.com. “We plan to phase out all HFCs by 2035.” CO2 systems will continue to be the prototype, supplemented by hydrocarbon-based integral (self-contained) display cases.
Tesco operates primarily in the U.K., where it is the leading grocery chain by revenue. It also has stores in Ireland, the Czech Republic, Slovakia and Hungary.
Moving to natural refrigerants is “a big driver” of Tesco’s overall effort to become net zero in emissions by 2035, said Holzer. In addition, all of its electricity is derived from renewable sources, and it is working with suppliers on their net-zero programs.
Another factor in the net-zero plan is the decarbonization of heating, for which Tesco is using heat reclaimed from refrigeration and heat pumps using natural refrigerants, particularly hydrocarbons, he said. “Our model is to use heat recovery, and top it off with heat pumps.”
A water system, managed by controls, is connected to the refrigeration to “extract as much heat as possible,” at optimal times, said Holzer.
Challenge of extremely high ambients
Holzer acknowledged that last summer, extremely high ambient temperatures in the U.K., reaching a record 40°C (104°F), challenged the operation of the CO2 systems, which were designed for 32°C (90°F) and capable of going up to 36°C (97°F), causing some to fail.
Projected higher temperatures will change the types of systems that Tesco selects. “Higher ambient temps and higher discharge pressures requires consideration of things like ejectors and parallel compression,” he said. Control systems will also play a key role.
Notwithstanding the exceptionally high summer temperatures, “we are confident of our choice to go to CO2,” Holzer said.
Last year, a Tesco Metro store located on the ground, basement and first floors of a building in central Birmingham, West Midlands, U.K., installed two of TEKO’s ROXSTAcube transcritical CO2 units on the roof, seven floors up and 40 meters in from the nearest (very narrow) street.
“Six years ago we decided all new [refrigeration] systems would be CO2.”Philipp Holzer, Tesco
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