The Borgen Community Centre is located in a suburban area in Asker close to Oslo, the capital of Norway. The Borgen School was built in 1970 and retrofitted and converted in 2005 to Borgen Community Centre, a place for the whole neighbourhood. The Centre contains public services and private organisations. The main building contains a secondary school and facilities for health-care services and leisure-time arrangements. One goal was to increase the possibilities for the local community to use the facilities, and thereby obtain social and economic benefits. The main building consists of 4,000 m² of renovated areas and 2,000 m² of new constructions.
The renewal of the main building was comprehensive, making the building suited for new working methods in school and for a diversity of activities as a result of new tenants from the neighbourhood. The existing building was poorly ventilated, had minimal daylighting, and was not suited for modern working methods and cultural and social activities. The plan layout was totally changed. The most visible feature of the renewed building is the daylighting openings on the roof and the new facades.
The main building is a demonstration building in the EU project «Bringing Retrofit Innovation to Application in Public Buildings», which run from 2004 to 2008.
Objectives regarding energy efficiency were emphasised and put into specific terms:
• In accordance with standard practice, the school section should be space efficient and adaptable to various working methods and social events. A large part of the building should be accessible and suitable for various groups in the local community.
• In accordance with the Norwegian assessment method «EcoProfile» the building and yard should obtain the best quality class for each of the three main areas: Environment, Resources, and Indoor climate.
• Purchased energy consumption for space heating, ventilation and artificial lighting should be halved by applying energy-efficient solutions and utilising renewable energy.
• Strategy for energy efficiency: In aiming to reduce the consumption of energy, the strategy «trias energetica» was used, i.e. initially apply energy-efficient measures, then utilise renewable energy resources, and lastly supply remaining demand with an effective fuel burner.
• Area use: Space efficiency and building flexibility are probably the factors that contribute the most to reducing the consumption of resources in a life-cycle perspective. In the community centre, public services and private organisations share rooms and equipment.
• Insulation: Roof and facades are upgraded with respect to thermal insulation.
• Daylighting: Daylight is used to reduce the expenditure of electrical power for artificial lighting. Daylight sensors controll the use of artificial lighting. Due to new regulations on snow loads, the roof construction had to be strengthened. The roof surface had to be replaced, and this allowed the installation of daylighting openings. The windows in the facades are enlarged and upgraded with respect to thermal insulation and solar shading.
• Ventilation: The building is provided with decentralised hybrid ventilation systems utilizing natural driving forces, buoyancy and wind, in order to reduce the demand for fan power. Demand control of airflow, heat recovery and low-emitting building materials further contribute to the energy savings.
• Energy supply: Geothermal heat (heat pump) is utilised for space heating, preheating of ventilation air and domestic hot water. Under normal conditions the geothermal heat is enough, and the backup system of oil burners are used only a few days during winter.