Refurb completes boasting lowest CO2 emissions in the UK
The recently completed refurbishment of Elizabeth II Court (formerly Ashburton Court) in the centre of Winchester turned a tired, dilapidated 1960s office block into a modern, efficient and highly sustainable working environment for Hampshire County Council (HCC).
Undertaken in two main phases between Spring 2007 and Summer 2009, the 12,600 sq m building replaces the previous institutional working environment of corridors and cellular rooms with modern, flexible open-plan office space. An area of car parking has been cleared to create a welcoming new entrance together with a 200 seat auditorium, meeting rooms, a café and restaurant laid out around new landscaped courtyards. Externally the appearance has been transformed into a modern building using local materials that is much more in harmony with its historic context.
But it's the project's green credentials that will get chins wagging. The new building, designed by Bennetts Associates is predicted to be BREEAM Excellent and to produce one of the lowest levels of CO2 emissions of any building in the UK, according to early design modelling and analysis keeping the project on plan to meet the UK government’s 2050 target for carbon reduction.
Answering conditions such as the introduction of flexible working, a tight budget, the congregation of several units into one building an of course, sustainability, the design solution has reduced the carbon emissions level for the transformed building from 90kg CO2/m2/annum to a targeted level of 39kg CO2/m2/annum. Over time it is believed the building could achieve around 30kg CO2/m2/annum, possibly even lower representing an annual reduction of around 70%, equivalent to 200 average UK households. The Carbon Trust is using Elizabeth II Court as a case study to evaluate reductions in carbon emissions that can be achieved through refurbishment
The building is predominantly naturally ventilated via a carefully engineered and innovative solution. Acoustic studies indicated that open windows were not feasible on the street facing elevations due to noise levels from traffic, so a system was devised whereby air is drawn from the internal courtyards across the floorplates and expelled through ducts or ‘chimneys’ along the street façades. The ducts have devices at the top called ‘wind troughs’ that use ‘renewable’ wind energy to create the suction force that drives the system. The new street elevations self shade the building and break up the massing of the façade in a way that relates to the character and materiality of the historic Winchester townscape.
Retention of the concrete frame saved 50% of the embodied energy normally required to construct a building and use of local bricks and timber based window systems helped to significantly reduce related CO2 emissions. A large proportion of demolition materials were recycled through the contractor’s supply chain, including former pre-cast concrete cladding panels that were crushed off-site and re-used as aggregate in other Hampshire projects. Waste heat from cooling plant required to service the Council’s Data Centre will be recycled to heat areas of the building in winter. Solar shading, intelligent lighting systems that switch off when not required, exposing of the concrete soffits for thermal mass and a new energy-efficient building envelope, all contribute to energy savings. Water saving devices in toilets and washrooms have also been installed to keep consumption within previous levels despite nearly doubling the occupancy. The new working environment is flexible and stimulating with a very positive reaction from staff and users thus far.
Leader of Hampshire County Council, Councillor Ken Thornber said: “As we rightly predicted, Elizabeth II Court’s environmental credentials are exemplary and it represents a clear example to other public bodies of what can be achieved with sustainable and creative reuse. In developing the design for the building, we have worked with some of the UK's leading experts in sustainable design, and it is expected to secure a BREEAM (Building Research Establishment Environmental Assessment Method) rating of `Excellent' - the highest possible achievement."