When Waitrose began looking at tough energy and carbon reduction targets to be rolled out across the entire business, it was clear that the energy consumption within its retail branches was a major element to consider.
Within that energy consumption, by far the most energy hungry equipment was refrigeration. The energy consumption of refrigeration contributed heavily to Waitrose’s carbon footprint; the existing refrigeration systems leaked gasses, as all Direct Expansion systems do, which caused further environmental concern. How did Waitrose solve this tricky issue? Read on to find out.
Since 2007, Waitrose has had in place a Responsible Development Framework, which stipulates that that all development works must be carried out in a sustainable and responsible manner. This is what led Waitrose to ask us at Synergy, working in collaboration with others, to devise an entirely new solution that would help them to achieve their targets. These included a reduction in absolute operational CO2 emissions by 15% by 2020/21, as well as the removal of harmful refrigeration gasses.
The existing type of refrigeration used at Waitrose, and indeed throughout UK retail stores, was fed through Direct Expansion refrigeration. This uses gases that are pumped around the refrigeration system to create cooling. However, there is one inherent flaw in this system (apart from its high energy consumption) – they leak the gas. These gases have a global warming potential of around 3.5 thousand and were a significant factor in the carbon emissions of each store.
In the face of new legislation on gas leakage and emissions, some other retailers opted to install a refrigeration solution utilising CO2 as the refrigerant replacement to HFC gases, a system widely used in America. Whilst this did in fact reduce CO2 emissions, it simultaneously increased the amount of electrical energy used, which effectively removed one problem and created another. Another reason that Waitrose wanted to avoid this option was that it was a relatively new process, at least in the UK, and there was a lack of engineers that were fully experienced in its maintenance.
Synergy, along with its partners, used a new technique derived from existing technology. The Mark 1 water-cooled refrigeration solution was developed using water, along with a low global warming impact natural refrigerant. Whilst the notion of water-cooled solution was not new, its application with a natural refrigerant chiller was. This solution provides minimum environmental impact, a 20% reduction in energy, and increased reliability. In addition, a water-cooled solution increases the possibility of integration with the store’s existing heating and water heating systems.
To date, no gas has been lost since using this system. The other major benefit is that because it uses existing technology, the maintenance of the system is straightforward and the need for, and cost of, re-training has been greatly reduced.
Waitrose continue to be very happy with the solution and, six years on, all new stores since 2009 have had this system installed.