R454A system in Trafford Park store claims efficiency improvement over natural alternatives
Retailer Asda is claiming a world-first with its Trafford Park store, which is now running a system on the ‘very-low-GWP’ HFO R454A. The installation is being hailed as a breakthrough for HFOs as it is not only running with a greatly reduced GWP of 238, but its operational costs are better than the available ultra-low alternatives - and equivalent to the system it replaced.
The designation ’very low-GWP’ is being used where the GWP approaches that of the ’ultra-low’ cutoff of 150 GWP.
According to Asda’s head of construction and design standards Brian Churchyard this makes it the ‘world’s first truly commercially viable HFO system’. He said: “The system is delivered at a lower cost to the industry-leading technologies, such as CO2 with equivalent lifecycle costs to our current model. Our aim is to create an A2L design stand over time so any lower flammability HFO can be used.”
The R454A system - a medium temperature application which is less than 40 kW in capacity and below the required 54 kg charge limit, and a low temperature application of circa 15 kW capacity with an 11 kg charge - has been tested and evaluated in detail in Asda’s test centre in Leeds.
Mr Churchyard says arriving at the Trafford Park configuration has followed extensive trialling. “Asda has trialled numerous alternative refrigeration technologies to support the continued phase down of potent HFC refrigerants with varied levels of success. All of these trials have been benchmarked against the most recent Asda model design standard on a like-for-like basis. With the release of HFO refrigerant technology, Asda has now been able to develop a commercially viable HFO based system for the Asda Trafford Park store, fully operational and on a similar basis of design to the original test trial.”
He said the key was that even with ‘belt and braces’ mitigation of the lower flammability of the HFO (see below), the system has been achieved at a significantly lower cost versus against alternative F-gas compliant refrigeration systems trialled by Asda over the past decade. He said: “Further energy savings have been achieved, verified through independent evaluation, and the maintenance requirements are very familiar for the existing service engineering base. System reliability, in combination with safety performance (being paramount), are expected to mirror the near 100 per cent uptime trading success that Asda have become accustomed to.”
The development of the HFO system has seen Asda take a conservative approach to the risks of the A2L refrigerant. A collaborative technical working group has designed and landed these systems to the A3 (flammable) safety standard, he said: “A detailed DSEAR assessment has been conducted within a controlled, non-public facing environment. From the rigours of testing, the working group have learnt a great deal and collated a large compendium of technical detail and data, trial findings and next steps. Asda and its technical partners are now able to confidently assess where they can safely and viably align this standard to a 2L equivalent.”
This year will see more HFO technology landed in Asda’s new Worksop store, with plans in the pipeline for a further rollout in 2020.
Mr Churchyard said that the system proves the worth of Asda’s refrigeration strategy of continuous innovation: “This guarantees the art of the possible, by not only meeting the needs of Asda customers but also looking to address critical environmental challenges in the face of rigorous and challenging regulation.”
Asda believes that the past decade’s achievements bears out the importance of a focus on containment – the headline figure of 2.5 million tonnes CO₂e mitigated emissions for refrigeration comes against the back drop of a rapidly growing estate and increase in additional cooling capacity. Mr Churchyard said: “Through specification change, innovation and consistent application of engineering best practice, Asda has reduced the power absorbed for its standard refrigeration model design by over 30 per cent; the average estate annual leakage rate remains below 8 per cent; and new installations are below 4 per cent.”
The retailer is also proclaiming significant success with another ‘disruptive’ innovation: its Mistral ducted display case system. As it rolls out the system, it has achieved 50 per cent savings in maintenance costs, Mr Churchyard claims, along with 40 per cent lower refrigerant gas charge and, most significantly, an 11 per cent reduction in energy.
A further success in Asda’s refrigeration strategy involves demand side management. This initiative currently creates up to 20MW of virtual power which can support up to 80,000 homes. Asda’s aim is to double this in 2020, Mr Churchyard said: “Having the ability to shut down and restart refrigeration systems when required, continuing to support grid balancing whist also saving money, will allow Asda to continue on their low carbon and energy efficiency journey with confidence.”