From the autumn 2012 Stenlille School in Sorø Municipality is going to have a new building for the lower secondary classes. The 1,350 m² large building will have low energy consumption, great indoor climate, flexible and inspiring classrooms and double use of walking and common areas. ALECTIA will advise on all the engineering disciplines and has won the competition together with Kant Architects and Kragh & Berglund Landscape Architects.

The construction of a future building for the lower secondary classes on Stenlille School in Sorø Municipality has been won by the consultancy company ALECTIA, Kant Architects and Kragh & Berglund Landscape Architects.

The basis of the extension of Stenlille School is the connection with the existing buildings. The new building will be connected to the existing buildings at the same time as it will be individual with a modern expression that signals “school”.

ALECTIA’s advising includes all the engineering disciplines such as buildings, installations, fire and protection, electrical installations, HVVS, energy, lightning and indoor climate.

Low energy consumption and fantastic indoor climate
At the extension of Stenlille School great focus has been placed on establishing low energy consumption and fantastic indoor climate creating optimal indoor climate conditions for learning, health and well-being.

Time after time examinations have shown that the CO₂ concentration and the temperatures in classrooms are too high and that the learning process can be improved up to 15-20% by having a good indoor climate in the schools. At the same time the pupils will be more quiet and focused, and for certain, with better indoor climate reduced sickness absence will be registered, both among teachers as well as pupils.

Energy-optimized architecture and environmentally friendly materials
The compact form of the building and the moderate glass areas and large roof overhang are the primary cause of the low energy consumption of the building. Focus has been placed on exactly these energy elements as these are “free” compared to continuous energy production.

All surfaces, to which pupils and employees are exposed, consist of environmentally friendly materials in the form of green-labelled products or surface treatments. This minimizes the allergens in the indoor climate and reduces the need for ventilation.

Green roof and good daylight
The large green roof is a unifying element for the building. The roofs are suggested to be covered with sedum/stonecrop, which during the year will change colour from brown to green to flowering. Under the roof there is room for variation, which encourages both play and learning – the serious and the funny.

The window sections are placed so that they give good light to the rooms. In the classrooms there is a window section with glass door and niche that activate the window front at the same time as it gives a good view from the classrooms. The highly placed windows give light to the depth of the building making the need for artificial light minimal, even furthest away from the front. In the interior learning and play landscape there is either glass from floor to ceiling or north-facing skylight ensuring good daylight conditions at the same time as there is another “atmosphere of light” than in the classrooms.

Energy-efficient ventilation concept
Demand-driven ventilation with heat-recovery. Injection into the cavity between the roof deck underside and the suspended woodcrete ceiling makes it possible to cool the roof deck at night in order to release the stored cooling efficiency in the daytime. This injection principle both ensures cheap cooling and low injection velocity as the injected air is diffused throughout the woodcrete ceiling, and in that way the solution gives a pleasant air change without any draught problems.

The energy demand of the building
A preliminary Be10 calculation shows an energy demand of 33.9 kWh/m² every year, which is more than 50% lower than the minimum requirement in the building regulations. The low energy demand is mainly due to the passive measures incorporated into the building, including a relatively compact building shell, optimized window areas and orientation, rational position of ventilation units and electrical routings and the chosen injection principle with injection above the ceiling.

Optimal indoor climate conditions
Most of the time the thermal indoor climate is thermal indoor climate class 1, see the indoor climate standard DS/EN 15251.

The mechanical ventilation plant ensures that the air quality always meets the building regulation requirements. The daylight factor is higher than 2% in approx. 75% of the room and never lower than 1%. In that way the indoor climate has the most optimal indoor climate conditions for learning, health and well-being.

Energy-efficient ventilation

• Demand-driven
• Low power consumption, good heat recovery
• Injection above the ceiling gives a pleasant air change
• Efficient night cooling of the concrete deck improves the indoor climate

Constructions

• Low heat loss
• No thermal bridges

Energy-efficient lightning

• A daylight factor of 2% in the main part of the classroom
• General lightning 7 W/m² at 200 Lux

Windows

• Low heat loss
• Suitable energy subsidies
• Minimal superheating

Low-emitting materials

• Healthier indoor climate
• Lower energy consumption for ventilation

Solar energy

• Solar cells contribute to a CO₂-friendly operation

Green roofs (sedum)

• The plants absorb CO₂ and produce oxygen
• Retains large amounts of water
• Insulating effect