nef and the national
energy centre
The National Energy Foundation (NEF) is a registered charity set up in Milton Keynes in 1990 to encouarge the more efficient use of energy and sustainable energy sources. Its initial work was to develop some of the ideas created in Milton Keynes and to take them forward onto a national stage, including the National Home Energy Rating scheme (NHER). The Foundation works through practical advice and help in installing energy saving measures and implementing appropriate renewable energy sources.
In 1999, the National Energy Foundation moved into the National Energy Centre, a purpose-built low energy office complex in Knowlhill.
The National Energy Foundation
NEF aims to help people and businesses throughout the UK to reduce their carbon emissions through the use of energy efficiency measures and renewable energy sources to help combat climate change. It undertakes this through the following activities:
- Offering Information, Advice and more Technical Support through its websites and consultancy team;
- Providing Infrastructure support, especially in the areas of Energy Certification and Standards, for example though its work in support of the Carbon Tust Standard, the Solar Trade Association;
- Working in Education, including its Green Energy Machine shown here;
- Undertaking Projects in collaboration with other organisations at a local, regional and European level.
The National Energy Centre
The National Energy Centre is the headquarters of NEF as well as United Sustainable Energy Agency (USEA, which operates the Energy Saving Trust Advice Centre), National Energy Services Ltd, the National Home Energy Rating scheme and a number of trade associations active in the field of solar energy and ground source heating. It consists of two contrasting low energy buildings completed in 1999 and 2004.
Phase I
The initial brief for the Phase I of the Centre was to create a building that would use 40% less energy for space heating/cooling than CIBSE standards, yet be constructed at no extra cost to more conventional buildings and have a long design life and provide a pleasant working atmosphere. Weston Williamson, architects, won a competition to design the Centre, with a team including Ove Arup who were responsible for the energy strategy.
The strategy was to provide a high thermal inertia (mass) using exposed concrete ceilings on ground floor, multiple layer dense cement fibre boards on first floor ceiling and blockwork walls. Heating comes from a domestic scale condensing boiler through conventional radiators. The building is able to passively vent overnight in summer and has external overshading designed to prevent solar gain in summer, but to allow natural daylight deep into the building in winter.
Phase II
In contrast, the second phase of the National Energy Centre in Milton Keynes was designed to have a low thermal mass and low embodied thermal energy. This building was designed by the local firm of Avebury Projects.
The building is highly insulated and uses a 13kW Viessmann heat pump to provide warm water to an underfloor low temperature central heating system, avoiding the need for radiators on the limited wall space. Initial plans to marry the heat pump to a highly efficient condensing boiler were changed when it was realised that cost savings through omitting the gas supply, boilers and sequencing controls would permit the entire building to be heated from a heat pump unit. A small pellet-fired wood burning stove has been fitted as an auxiliary heating system, although it is only rarely used, even in the middle of winter.
On bright days, the heat pump can be powered by a 6.47kWp photovoltaic (PV) array. Hot water for the kitchen and toilets is pre-heated by a Thermomax evacuated tube solar collector. The National Energy Foundation has worked closely with Avebury International in creating this design for a low energy building; Avebury also provided the construction management services for the new building.
The west elevation of the building has a mixture of horizontal and vertical glazed areas including high level natural ventilation and vertical/horizontal shade panels. This has been constructed using a timber frame, with brick walls below the windows and on the North and South aspects, and low maintenance 'Thermowood' cladding produced from sustainable (Scandinavian) timber elsewhere. The east elevation is partly buried to achieve thermal stability and reduce the visual impact from the office area of the Phase I building. A four-ridged mono-pitch North light style roof sloping at 7.5° towards the East and 15° to the south has been used to improve the angle for the PV installation.
The building has been closely monitored since its construction and has an exemplary energy performance of around 65kWh/m2 (gross), reduced to 55kWh/m2 in net terms after allowing for the solar electricity production.
Please note...
The National Energy Centre is a working office building and is not open to the public. For more information, including public access opportunities, please visit the NEF website.
