Sainsbury's fitted F1-style aerofoils to open chillers to keep cold air in

Supermarkets keep chillers open because, as Sainsbury's sustainability head put it, shoppers disliked opening doors; a Carbon Trust director suspected it was more about marketing. Open fronts spill cold air into the aisle. Refrigeration typically accounts for half of a supermarket's energy bill, and Sainsbury's electricity bill runs to hundreds of millions of pounds.

Williams Advanced Engineering, the spin-off of the Williams F1 team, worked with Aerofoil Energy on a thin strip of aluminium and plastic shaped like a wing and attached to the front of the shelves. WAE's managing director said it acts like an F1 rear wing, guiding air into an air curtain.

Sainsbury's decided to fit the strips in as many of its 1,400 supermarkets and convenience stores as it could, and said it cut refrigeration costs by up to 15%.

Borrow Formula 1 airflow control: a wing-shaped strip on each shelf edge turns spilled air into a curtain.

Open cabinets lose cold air into the store, so the compressors work harder.

A wing shape keeps airflow attached close to the cabinet and forms the curtain.

The strip is a cheap bolt-on that needs no new cabinets or doors.

Formula 1 teams are skilled at managing airflow, so the idea came from outside retail.

Look to an unrelated industry for a cheap retrofit to a chronic loss, instead of redesigning the whole system.

BBC reported in 2017 that Sainsbury's put the saving at up to 15%, nearly 10 million pounds a year. The Carbon Trust's Myles McCarthy called it a stop-gap and said sliding or pull-out doors could cut electricity use by 30-40%. The claimed savings are the retailer's own figures.