June 6, 2007
Concrete answer to commercial zero carbon challenge
The Government is to launch an urgent drive to reduce the carbon emissions of commercial buildings, in particular the amount of CO2 emissions resulting from their day-to-day use. The operation of buildings in the UK accounts from some
50% of total CO2 emissions.
Yvette Cooper, the housing and planning minister, has commissioned a task force drawn up from representatives from the property industry, retailers and environmental groups, to draw up a series of deadlines by which all new commercial buildings will
have to be ‘zero carbon’. The move follows the Government’s announcement at the end of 2006 that all new homes must be zero carbon within the decade. Announcing the initiative, Ms Cooper said: “Buildings account for half of the country’s carbon emissions. We have set ambitious targets for housing and are now determined to make rapid progress on commercial buildings too.”
Air conditioning is responsible for a growing proportion of this. Uptake of air-conditioning in the UK is rising by 8% annually, an increase which could lead to six million extra tonnes of CO2 per year by 2020. Predictions from the UK Climate Impacts Programme show that by 2080 the summer temperature for the UK could increase by 60. Unfortunately, many commercial buildings are already suffering from overheating and are increasing their reliance on energy guzzling air conditioning.
However, there is a relatively simple and environmentally benign solution. “Utilising the thermal mass of a building in combination with night-time cooling can reduce or even eliminate the need for air-conditioning,” explained Steve Elliott, project director of the
British Association of Reinforcement (BAR) “This is usually referred to as Fabric Energy Storage (FES) and should be at the heart of low-energy building design.”
The thermal mass of FES allows a building fabric to interact with and stabilise the internal and external environmental. Here, the unrivalled, inherent thermal mass of concrete can be used to play an increasingly important role in ensuring comfortable internal temperatures in commercial buildings without recourse to air-conditioning. The basic approach is to expose the soffit of floor slabs which can then absorb heat gains. Cool night air is then used to ventilate the building and remove the accumulated heat from the soffits in readiness for the next day. Similarly, the heat absorption ability of concrete can reduce heating requirements during the winter. Here, the concrete absorbs heat from the sun and from electrical equipment. This heat is then released during the night. FES has been used by an increasing number of offices in the UK as designers and developers meet the demand for more energy efficient buildings.
“Concrete’s thermal mass is inherent and free of charge. FES offers energy efficiency that is integral to the building fabric rather than a further add-on”, said Elliott. “This makes it particularly able to answer the zero carbon challenge.”
