Asda, Marks and Spencer, Sainsbury’s, Somerfield, Tesco, and Waitrose told suppliers in March that the "future was natural refrigerants" with a "minimal impact on the environment".
Speaking at RAC 2007, the trade refrigeration and air conditioning event, the group called on companies to develop energy-efficient systems using natural fluids and link stores’ heating and cooling systems.
"We need companies that are looking wider than just refrigeration. The whole concept has to be revisited," said Andy Campbell, refrigeration manager at Tesco. "It’s a design challenge, but integration of systems is something we will have to do."
The group said systems must focus on sustainability, specifically life-cycle impacts, the role of renewable energy and end-of-life disposal.
The supermarkets have come together under the umbrella of the British Refrigeration Association’s End Users Group to work with suppliers and share experiences testing and using natural refrigerants. It signals a growing pressure on retailers to address refrigeration’s impacts.
Hydrofluorocarbon (HFC) gases, the industry standard for refrigeration, were introduced in the 1990s in the rush to replace ozone-depleting hydrochlorofluorocarbons (HCFCs) and chlorofluorocarbons.
With commitments under the Montreal Protocol to phase out remaining HCFCs, efforts to replace the chemicals with HFCs are accelerating (see table).
Both Marks and Spencer and Morrisons are replacing HCFC refrigerants with HFCs, with the former aiming to complete its £11 million programme by 2008. Last year, HFCs made up 91% of Tesco’s refrigerants.
However, critics have long called for a phase-out of HFCs because of their high global warming potential and tendency to leak. One tonne of the industry favourite HFC R404a is equivalent to 1,300 tonnes of CO2.
Many fear new controls to minimise leakage rates in the EU Regulation on F-gases, which takes effect this July, herald a total ban on the substance. If true, it could mean yet another costly replacement exercise for the sector - the third in less than 15 years.
Sainsbury’s refrigeration manager John Skelton said they could not carry on "trialling and investing in technologies which have a shorter life span than the equipment", a sentiment echoed by refrigeration manager at Marks and Spencer Bob Arthur.
In addition, the energy burden of refrigeration systems is significant, accounting for half of the supermarkets’ £1 billion annual electricity bill, leading to 2.8 million tonnes of CO2 every year. The overall efficiency of the systems will be just as important as the refrigerants used.
The key natural refrigerants being studied are ammonia, hydrocarbons and CO2, which have less global warming potential.
Frozen-food retailer Iceland first broke the mould and declared its support for hydrocarbon-based refrigeration technology in the late 1990s. This move followed several years of campaigning by Greenpeace to help companies offering hydrocarbon refrigerants overcome industry resistance (ENDS Report 285, pp 32-33 ).
While ammonia is increasingly used in distribution centres and hydrocarbons have become the norm for small and domestic fridges, CO2 continues to show the most promise for retail-size operations.
Professor Graeme Maidment of South Bank University, who is developing a sustainable refrigeration network with the Institute of Refrigeration, said that despite debates over the energy efficiency of CO2-based approaches new systems are showing "reasonable efficiencies" and when combined with hydrocarbons or HFCs they are demonstrating "better or more comparable efficiencies".
He agreed higher efficiencies could be achieved by linking demand for cooling and heating but stressed no one has tested this yet.
Last April, Tesco and Italian-based commercial refrigeration firm EPTA installed a CO2 system in Tesco’s Swansea Extra store which they claimed reduced the system’s global warming potential by 99.98%, equivalent to a CO2 reduction from 652 tonnes to 0.137 tonnes.
New energy-efficiency measures, such as low-energy evaporator fans, front risers to chiller cabinets and changes to lighting, were also incorporated. EPTA claims this halved energy use.
EPTA, which was the first to introduce CO2 systems into supermarkets, said the technology is viable but until components become more widely available setup costs will remain high.
Sainsbury’s, which also tested CO2 at its Clapham store in London, found that while the system had performed well, a lack of relevant skills and equipment to operate and maintain the high-pressure systems made it an expensive option in the short term.
"It’s chicken and egg. There needs to be a wholesale change in the components supply chain and in the competence of the people who maintain the system in order to bring down costs," said John Austin-Davies, EPTA’s product marketing director.
Cedric Sloan, BRA director general, warned it could take more than three years "to train people with the right skills and a similar amount of time for suppliers of components and systems to get into a position to get this up and running".