Improving energy efficiency is revolutionising retail
Improving the energy efficiency of the UK’s food retail chain has been the focus of a team at Brunel led by Professor Savvas Tassou for more than a decade.
Since 2001, they have been working to refine three core processes that between them have the capacity to revolutionise heating, refrigeration and food handling in retail stores.
The three processes are:
- Combined Heat and Power (CHP), which is the simultaneous generation of electrical power and thermal energy,
- Tri-generation, which is simultaneous production of electricity, heat and refrigeration, and
- efficient refrigeration systems that use CO2 as a refrigerant, rather than the environmentally-unfriendly fluorocarbon gases commonly used today.
This work has been closely followed and well-supported by government and by the retail food industry. Refrigeration alone accounts for up to 60% of the total energy consumption of retail food stores and 15-20% of the carbon footprint of retail food chains in the UK, so any systems that can improve these figures would be very valuable in such a highly competitive sector.
Professor Tassou’s team has concentrated on demonstrating that these concepts can be made to work in a retail environment. For example, one feasibility study on a low temperature absorption refrigeration system, driven by the waste heat from a CHP system, showed that these could cut running costs by 25% compared with the cost of buying power from the national grid and using it to drive conventional vapour compression refrigeration systems in the store.
Major supermarkets including Marks and Spencer, Sainsburys and Tesco have responded rapidly to the potential benefits of these technologies. Marks and Spencer is using CO2 refrigeration systems to help reduce carbon emissions by 60% in 2013, compared with a 2006/7, saving over £4 million a year in the process.
Tesco has installed CHP and Tri-generation with CO2 refrigeration in its store in Cheetham Hill, Manchester, which opened in 2009. The retailer says that the store has a carbon footprint 70 percent smaller than equivalent stores built only three years previously. The CHP plant has reduced the carbon footprint by a third, and the CO2 refrigeration system by a fifth.
Professer Tassou is building on this work with the establishment in 2013 of the Centre for Sustainable Energy Use in Food Chains, intended to provide a focus for work on energy efficiency all the way from field to plate.