When Asdas parent company Walmart decided that they would present their British operation with the challenge of producing their most energy efficient, low carbon store in the world SilcockLeedham LLP where approached to help deliver the challenge.

In the first instance appointed as Research and Development Consultants we were tasked with investigating the different sustainable options available and how they could be incorporated within a food store environment.

Secondly we were appointed as the Building Services consultants for their first Low Carbon Store. From previous experience Walmart were concerned that the building did not just become a standard store with a number of environmental bolt-ons. They were keen for us to investigate the whole of the stores operations and drastically improve its energy consumption even if this meant a change to their successful model store arrangement.

Taking the Research and Development knowledge we had developed we adapted solutions to suit the store and site constraints.

We developed a building services strategy that utilised the stores operations to enhance efficiencies. Using underfloor heating and cooling with occupancy driven ventilation we were able to treat the occupied zone with its exact requirements.

We are utilising an underground aquifer for our prime heating and cooling source. Which not only provides an extremely low energy source for the environmental systems. It also enables us to utilise it to significantly improve the efficiency of the refrigeration sytems. In turn the heat reclaimed from the refrigeration systems is our main energy source for hot water generation. Only being topped up by the Biomass boiler under peak demands.

With the introduction of CO² as the refrigerant coolant for all the stores requirements as well as any ancillary environmental requirements we were able to make the store completely HCFC free.

By introducing North lights and translucent curtain walling systems to the main sales floor area natural light has been introduced evenly across the sales floor. Coupled with an integrated lighting control system we are able to dramatically reduce the energy demand of the lighting systems.

By positioning Photovoltaic panels on the north lights we are able to improve the efficiency of their operation and by connecting them to the till area loads we are able to allow the store to operate under power loss.

Using these and other energy and control solutions we estimate that the energy saving to the store will be in excess of 40% when compared to an existing model store. Whilst recognising that the cost of the sustainable solutions must provide a cost effective solution for future store developments.

The completion of the Low Carbon Store is due for completion in early 2008 and is to become a Case Study by the Carbon Trust and progress of the project can be followed on their website.