Designed to serve the 1300-home millennium village, the new Sainsbury's aims to lead the world in design and energy efficiency. It has a sales area of 33,500m2, a bakery, delicatessen and restaurant, and a relatively modest 550-space car park. It has a breeam rating of 31 out of 31. Oscar Faber was the services engineer and wsp the structural engineer.
It is set into earth-sheltering bunds lined with massive concrete walls which help to reduce temperature fluctuations. The roof is supported on a relatively lightweight steel frame which was quick to erect, allowing construction of the roof to begin before the concrete walls were complete.
The majority (85 per cent) of the store's electricity is generated by a combined heat and power (chp) system. The waste heat produced is captured in water and used elsewhere in the store for heating.
Fresh air is drawn into the store through ground-level vents to a plenum beneath the floor. These vents connect to the sales area through grilles in the shelving and cabinets. The air is warmed when it passes over thin tubes, heated by the chp system, mounted at the entrance to the plenum. This causes the air to rise from the floor and pass out through louvres at high level.
There is also separate heating - or cooling - in the form of pipes embedded in the floor. A plate heat exchanger takes either waste heat from the chp plant to the pipes or cools them using borehole water, depending on the requirements at the time.