Linear actuators ensure the right building climate at the new airport terminal in Singapore
 
In the construction of Terminal 3 for Changi Airport in Singapore architects and designers were faced with a challenging task: The building with its 52,000 square metres was to be flooded with natural light – this was one of the requirements placed by the airport operator CAAS. In order to fulfil this requirement with average temperatures of 27 degrees Celsius and more coupled with vertical solar radiation when the sun reaches its zenith, they designed a complex roof construction. An innovative daylighting system allows light to enter the interior of the building while at the same time excluding the heat energy of the sun’s rays. Following its opening in 2008 employees and travellers can benefit from natural, glare-free light at the check-in counters and the 28 gates.
 

 
Butterflies for sun protection
 
Each of the 919 skylights in the roof construction has its own shading system comprising two aluminium panels. These are aligned like the wings of a butterfly and have thus been given the name “butterfly panels”. In combination with the east-west alignment of the building this results in an intelligent sun protection solution: When the sun rises in the east, the eastern wing of the skylight is closed, with light continuing to enter the building through the open western wing. If the sun is vertically above the light shaft, both wings are folded half-way down. Thus light enters the building from the sides, but no direct rays of sun enter the building. In the afternoon the west-facing panel is closed and the east panel opened. Insulated glass reduces the amount of energy entering the building by a further 15 per cent.
 

 
Tested and found to be good: Actuators from Germany
 
The aluminium wings of the “butterfly panels” are operated by nearly 2,000 electric push rod drives from the German company elero Linearantriebstechnik. The decisive factors for the choice of these linear actuators were their precision when they are operated to intermediate positions, the necessary ease of maintenance and their reliability. These qualities had to be demonstrated before construction of the terminal actually began: In 2003 a model of the roof was created so as to test the functioning and interplay of the individual sun protection and daylighting elements. In this respect the actuators defied the impact of monsoons and tropical heat, thus proving they were perfectly suited to use in this major project.
 

 
Lamps supplement daylight
 
The central control of the entire plant is taken care of by a bus system which controls the some 3,000 addresses in the roof truss of the terminal. In addition to the shading created by the “butterfly panels”, this also regulates the artificial lighting. Lamps are switched on and off according to the weather conditions and time of day. For example, the panels are closed in the event of a sudden shift from sunny to cloudy conditions – with the effect that only 10 per cent of the available natural daylight enters the building. Uniform illumination is then ensured by lamps which are installed in the skylights. In the twilight hours the decreasing amount of natural light is gradually supplemented by artificial light. Thus the system guarantees natural illumination, while at the same time preventing the terminal from being overheated by the equatorial sun.


 

 
The perforated aluminium panels on the roof of Terminal 3 at Changi Airport look like the folded wings of a butterfly – hence the name “Butterfly Panels”.Source: elero Linearantriebstechnik/durlum
 

 
Sun protection and the lighting system are accessible via the roof and can thus be maintained from above with very little effort. Source: elero Linearantriebstechnik/durlum
 

 
Daylight contributes to a positive room climate, helping a building’s users to perform better, attain smaller error quotas and feel better.Source: elero Linearantriebstechnik/Bartenbach LichtLabor
 

 
In the morning the sun is low in the eastern sky. Thanks to the intelligent sun protection system the sun’s rays are deflected and nevertheless daylight is guided into the building. Source: elero Linearantriebstechnik/Bartenbach LichtLaborWe will be pleased to send you print-ready images by post or e-mail.