There are several different motives behind the design and construction of the Sainsburys in Greenwich. Sainsburys as a company and corporate force wanted to create a supermarket showcasing their desire to be at the front of the drive for sustainability in retail. The project set was intended to include low energy technologies and be Britain’s first low energy supermarket. This wish to be perceived as ‘environmentally friendly’ has become common place amongst companies with large public interaction. In 2007 Sir Terry Leahy, chief executive of Tescos laid out a series of measures that he hoped would ignite “a revolution in green consumption.”
‘Compelled by economic necessity as much as by ecological awareness, many corporations now seem to compete as vigorously to display their environmental credentials as they do to sell their products.’ (Specter, 2008)
Before any design for the site in Greenwich had been finalised there was a two year research programme run by Sainsburys analysing energy usage in supermarkets across the country and low energy technologies that could be implemented or adapted to be used in the design of a new lower energy store. One of the points that emerged from the research that was undertaken was a tendency for supermarkets to be large artificially lit and ventilated, lifeless boxes. Designing a building that showed an alternative to this preconception and provided a light and airy experience became an important part of the brief. These changes described by Reid can cumulatively make significant changes in levels of C02 in the atomosphere.
‘Modest adjustments to investments by choosing low carbon technologies can, over time, bring much lower greenhouse gas emissions, even in cities with booming economies’ (Reid, 2007)
All aspects of the building are designed to aid its environmental, energy efficient plight, the building itself is set into five meter high earth banks, this decision was made to provide insulation for the store, integrating the build directly into the site and helping to cool the interior during the high temperatures of the summer months. The earth envelope also works to warm the spaces throughout the winter and create the dramatic curved appearance of the store.
The external walls are reinforced concrete, with a mineral or fibre based external insulation. During the day these walls draw heat from within the store which is retained throughout the day, the concrete acting as a heat sink. As temperatures drop into the evening and the store is closed, this heat begins to be released back into the store. The insulation and earth banks help to reduce the need for extra space heating, however Sainsburys has incorporated a floor level heating system into its design, where by waste heat generated through the stores refrigeration system is reused, passed through heated coils which are cast directly into the floor, running throughout the building. These provide most of the stores internal heating. A combined heat and power unit on site also provides extra power for the heating.
The flooring system also includes underground ductwork for use of passive ventilation. The ductwork draws air into the building from the outside, this air is then passed to secondary ducts which control the flow of air to grilles designed into the shelving units, distributing the fresh air to be circulated around the store.
The buildings roof as well as accentuating the designs curved appearance with its aerodynamic turtle shape is integral to the buildings sustainable design. The saw-toothed flat panelled steel and aluminium roof is designed to assist air flow, ventilation and heating. Continuous vents placed at the head of each of the saw toothed roof lights allow the air rising from the shelf grilles to escape. The ventilation and natural lighting is controlled by computer sensing technology, operated by a building management system. The extraction air vents and external aluminium louvres are both adjusted according to the weather conditions to provide the best natural lighting, passive heating and ventilation. The roof’s saw toothed design allows for a third of a mile of north faced glazed panels, maximising natural light in the store and helping to reduce solar gain on the glazing. The aluminium louvers on the outside act as thermal blinds to reduce thermal loss and artificial light pollution at night. A main feature of the supermarket’s design is the exploitation of natural lighting where by daylight enters through the glazed roof structure and is reflected back the white speckled terrazzo flooring creating a bright spacious atmosphere to the interior of the building. The shelf lighting system is only activated during overcast periods, minimising excess energy use.
The refrigeration system, essential to any supermarket is also custom designed to be more energy efficient and environmentally friendly. Water for the system is drawn from the London chalk through two 75 meter deep bore holes. The extensive refrigeration system does not use ozone damaging gases and an ozone benign propane refrigerant is used to cool the food stored for sale.
During the design process the orientation of the building was decided, the decision being made with the environmental aims of the building at the forefront of the reasoning. The building has a north south orientation, the main customer entrance located on the southern face. The orientation of the building was of the utmost importance because of the environmentally efficient aims of the design, the northern orientation allowing for the maximum possible daylight inside.
‘Integration of global environmental concerns into conventional building design strategies. Urban vision of the compact and dense city.’ (Guy, 2001)
This environmental logic is typical of organisations with large public engagement as the appearance of a ‘carbon aware’ business is the desired outcome. Showing the use of green technology is the most obvious way of communicating this point to customers.
When designing the store the surrounding area was also landscaped to provide a setting for the building, an artificial lake was included. This was incorporated for irrigation of the landscape surrounding the store, which has been planted with native woodland species and drought tolerant plants. The lake uses water from both the cooling system and rainwater from the roof to irrigate the surroundings. The rainwater is filtered before entering the lake, using the stores own reed bed system, removing any impurities before it is used for irrigation.
As well as an environmental ethic, resource efficiency was also an important factor in the design. The design was set out to be “lean” with major components and assemblies designed to cut out unnecessary duplications, so minimising resources required for the construction. The features such as under floor services and heating were part of this solution.
The supermarket was only a small part of the large millennium village master plan being implemented in the area. The addition of a green and sustainable supermarket not only provided local shopping for the community but also created job opportunities. The supermarket created 380 jobs for the local residents. The close proximity of the supermarket to the residential development also means that residents have the opportunity to travel to the supermarket on foot rather than by car, thereby eliminating unnecessary car travel.
One of the initial goals of the project was to produce a supermarket that would gain an “excellent” rating when assessed using the BREEAM environmental assessment method. Once completed the supermarket received 31 points, the only supermarket to achieve full marks on this assessment. This achievement and the serious environmental agenda behind its design has led to the claim of the Greenwich Sainsburys being the most energy efficient supermarket ever built, the sweeping aluminium roofed building uses 50% less energy than a standard supermarket.
