In the cooling industry in the United Kingdom, perhaps more than in any country in Europe, it is the supermarkets that are in the forefront of technology change. For instance, most U.K. supermarkets are not particularly fazed by the increased emphasis on low-GWP refrigerants that is being prompted by the EU's forthcoming F-Gas regulation, because they are already pretty well advanced on their own natural refrigerant strategies.
It might be understandable that with large stores filled with refrigeration, the supermarkets' strategies are going to be of crucial importance to the fortunes of the cooling industry, but it doesn’t automatically follow that it will be them leading the charge towards new technique and technology.
That the U.K.’s Big Six supermarket brands — Tesco, Sainsbury’s, Morrisons, Marks and Spencer, Waitrose and ASDA — do have such a fundamental role in steering cooling’s direction is down to a series of distinctive factors. First, there is the fact that these six have such a large volume of stores between them, concentrating the responsibility in only a relatively few hands. Second, the U.K. has historically retained engineering knowledge within the retail groups — even if it is only one or two individuals — rather than outsourcing the engineering responsibility to the contractor, which tends to be the norm in continental Europe. And third, these individuals are under pressure from their colleagues to contribute to their companies' CSR and carbon emissions policies.
This is a potent combination that has put real pressure onto the supermarket refrigeration staff to be creative in their cooling strategies. But now, the rising cost of energy has added another element — it has given the refrigeration manager the opportunity of doing something to make a significant impact on the bottom line.
It is power as well as responsibility.
Thus it is perhaps not so surprising that some retail refrigeration heads have grasped the opportunity enthusiastically. And currently, the retailer making the most waves is Sainsbury's, where head of U.K. refrigeration John Skelton has been a key part of an ambitious carbon reduction strategy.
Three years ago Sainsbury's published its "20X20 Sustainability Plan," as part of a wider ambition to become "the UK's greenest grocer." Its focus was to deliver a 30 percent absolute reduction and 65 percent relative reduction in carbon emissions by 2020, based on a 2006-07 baseline.
Key amongst its commitments in the cooling sphere is a very ambitious program of transcritical carbon dioxide refrigeration installations in stores large and small, coupled with the promise to be the world's first supermarket to be completely HFC-free by 2030. The retailer has around 184 stores running on natural refrigerant CO2, and reports that it is on track to achieve 200 stores by March 2015. If achieved, that will be 200 CO2 installations in just a five-year period. If that seems ambitious, you should know that the original plan was to open 250 in that period.
In so doing, Skelton has had to engage a U.K. supply chain in the task of developing CO2 technology and techniques it was not too familiar with at the outset. The retailer did this by working closely with suppliers to develop initially three different plant-and-installation contractor configurations, subsequently further rationalized to two.
Interestingly, comparative electricity monitoring has found that energy consumption at its zero-carbon CO2-cooled store at Leicester North is reduced by around 50 percent against three comparable HFC-based stores. Although it doesn’t include summer data, the gains delivered during the remainder of the year are so substantial that it is likely that full-year results will remain significantly ahead.
This, Sainsbury's says, provides compelling evidence that CO2, in conjunction with energy initiatives, delivers substantial savings. It has carried out trials at stores across the country to test the effectiveness of promising alternative technologies and approaches including different refrigerants, cabinet modifications, lighting technologies and control strategies.
It says, "We believe that solutions that are good for the environment need not necessarily be bad for business or the customer experience. Indeed, our experience in practice has taught us that these needs often coincide. We have therefore consciously sought win-win possibilities, and encouraged our suppliers to think also in these terms."
The range of equipment that is currently being trialed or adopted forms a veritable showcase of HVAC technology.
- It has to-date installed 125,455 PV panels, believed to be the largest multiroof solar array in Europe.
- Last year, it opened its first CO2-based convenience store, at Haslucks Green, Solihull, part of a range of low and zero carbon technologies, which have led it to claim the achievement of the "UK's greenest convenience store."
- It has installed 91 biomass boilers to heat stores and produce hot water, and now generates around 2 percent of the heat required across its stores.
- It has developed new borehole techniques to store and tap waste refrigeration heat underground for heating and cooling on demand, as well as installing conventional ground source heat pumps at both new and existing stores.
- The refrigerated air curtain has been removed from front of glass-doored chillers, reducing condensation and saving energy; The reduced H&V load, due to decreased cold air spillage, removes the need for an 8 kW AC unit per store, the retailer contends, saving further energy, cost and maintenance.
Sainsbury’s says it has so far reduced absolute carbon emissions by 12.7 per cent since 2007-08, despite a 31 percent growth in sales area. Impressively, it claims it is on track to deliver a 30 percent absolute reduction by 2020, and a 50 percent reduction by 2050. It also claims an 11.1 percent absolute reduction in supermarket electricity consumption in the same period.
Sainsbury's next phase is to build "triple zero" stores, encompassing zero operational carbon, zero waste and zero water. In terms of technology, the next promising initiative is away from the store — in the food distribution fleet. The retailer is currently halfway through a two-year trial of a carbon dioxide refrigerated truck. The technology from Carrier Transicold represents the conversion of a marine refrigeration system to a road-based use. If it proves successful, the conversion of the fleet could save the retailer more than 70,000 tonnes of CO2, Sainsbury's believes.
Transicold has developed an innovative refrigerant management system to accommodate the CO2, including a new purpose-built, multistage compressor with variable-speed drive, a gas cooler with a wraparound design and a flash tank to manage the flow and phase change of the refrigerant after leaving the gas cooler. The gas cooler coil wraps around the fan, maximizing heat-transfer surface area for greater efficiency in a compact and lightweight design, and provides gas cooling after each compression stage for better efficiency. For efficient cooling performance, the patented design enables final separation of CO2 from its gas phase to the liquid state before entering the evaporator.
The retailer says, "In terms of our philosophy of approach, while some retailers have sought to champion one or another technology solution, our approach has been open-minded and empirical. The aim has been to establish the most effective solutions — from an environmental, customer and business point of view."
