Asda trial finds huge HFO savings versus CO2
Supermarket giant releases findings from store trial looking at energy efficiency impacts of switching from older CO2 solution to a lower flammability A2L system.
Asda has posted the results of a 12-week store trial which have shown its HFO-based system used significantly less energy than its previous transcritical CO2 refrigeration model.
The results from the retailer’s Bootle store will be closely studied, given that it is believed to be the first time that a transcritical system has been replaced by an A2L one.
Brian Churchyard, Asda’s senior manager for Engineering, Net Zero and Energy said, “The energy savings are significant, equivalent to the benefits you would typically see when fitting doors to chilled display cases, the HFO design has provided a 35-40 per cent energy saving and 94 per cent GWP reduction versus our previous model design.”
Significantly, the R454A system installation was achieved at lower cost than the CO2 version too, including all the necessary mitigations for use of lower-flammability A2Ls.
The systems also uses up to 70 per cent less refrigerant charge and is a familiar technology for engineers to design, install and service, he noted.
Mr Churchyard said the replacement was necessary as the transcritical system was showing significant signs of corrosion, bringing the risk of catastrophic pressure loss.
He said, “When the previous CO2 system was installed it was thought to be the way forward, but after a detailed performance evaluation this rollout stalled as we had concerns around energy impacts and the system’s high pressure operation.
“Though the system had been reliable over the past 12-years, it proved costly to maintain and energy use had also been a concern even though the chilled display cases had doors fitted to them.”
Mr Churchyard noted that the success of the Bootle installation was the result of over three years’ worth of trialling, analysis and engineering input to optimise the operation with HFOs.