Building climate system regulates temperature of glass tube in Bocholt
 
The glass façade – one of the most striking style elements in modern architecture – has long been a topic of intense discussion among experts and laypersons alike. “Horrible sweat-boxes that waste electricity in an irresponsible manner” is how the German news magazine Der Spiegel has described fully-glazed buildings, for instance. Indeed in the summer months the climate in such glass palaces can be a real burden for the users of a building.

 

 
On the other hand, large glazed areas are of benefit in the cold winter months as the sun’s heat may be used to support the heating system. Moreover, the construction material glass means a building is uniquely transparent for its immediate environment, thus permitting rooms to be flooded with light and leaving a lasting impression in the eye of the beholder.
 

 
If an architect is not prepared to forego the design opportunities offered by glass and still wants to take into account building climate, ecological and economic aspects, a multi-component, coordinated building climate is indispensable. With a tube-shaped glass construction in Bocholt, for example, a combination of variable sun protection and natural ventilation using a smoke-heat extraction system, partial climatisation using concrete core activation and a photovoltaic unit ensures a balanced building climate and a favourable energy audit.
 

 
At the heart of the climate concept are slats made of green laminated glass with 50% of their area covered in white dots; these slats are moved in accordance with the position of the sun. Although shading was only necessary on the curved section facing south east, for design reasons the slats were also used on the north-west side. Initially it was not intended to use rotating shading slats for the building in Bocholt. However, a precise price calculation revealed that motorisation of the slats would only involve a marginal increase in costs, and the client decided to opt for dynamic, elements moved in accordance with the position of the sun, and thus for a more favourable energy audit.
 

 
The sun protection slats are moved by 60 drive units from the Econom 0 series from elero Linearantriebstechnik. The maintenance-free linear actuators ensure the precise alignment of the slats and keep them in the correct position. In this respect they combine intelligent technology with a robust, cylindrical construction in stainless steel, making them weather-resistant and ensuring a long service life.
Above all when a glass façade is chosen for aesthetic reasons, shading should be part of the architectural concept. In Bocholt, for instance, glass slats are used; in terms of appearance they correspond to that of the façade and emulate the convex shape of the exterior in an optimum manner.
 

 
When it comes to the automation of the slats, drive units such as the Econom, with its slender, inconspicuous design, have to be used so as not to detract from the appearance of the façade. In addition to its pleasing appearance, it is above all the adaptability of the linear actuator which makes it a suitable solution for numerous shading requirements: Not only glass slats such as those on the office and production building in Bocholt, but also horizontal or vertical aluminium slats, photovoltaic elements, ventilation windows and shutters/flaps, as well as innovative constructions such as folding elements, may be moved with the Econom 0.
 

 
Control of the slats is via a central regulation system in accordance with the level of solar radiation and local weather conditions. Thus in summer the best-possible protection against heat and glare is guaranteed, and in winter the sun’s energy is used to supplement the building’s heating systems. A photovoltaic unit, integrated into the front wall of the tube, rounds off the energy concept.
 

 
Natural ventilation of the production and office rooms was ensured using slat windows on the sides coupled with smoke and heat extraction systems in the ceilings. This sophisticated sun protection and ventilation system was supplemented by partial climatisation of the offices with the aid of so-called concrete core activation. In this respect concrete floors and walls are thermally activated, i.e. cooled or warmed using water-filled pipes. In summer the cooled concrete elements lower the inside temperature during the
day and, together with the other components, ensure a pleasant climate in the building. In winter the heated concrete warms offices and the production bay, ensuring a pleasant working temperature.

 

 
This optimum temperature regulation in a building can only be achieved through the interplay of several building technology elements. Individual drive units, controls, construction elements and technologies have to be integrated to form one system, for only with a holistic concept can a comfortable and productive climate be ensured in modern glass buildings.
 

 
Tube-shaped office and production building (lft) in Bocholt.
 

 
The Econom 0 from elero Linerantriebstechnik moves the sun protection slats.
 

 
Curved outer wall with closed sun protection slats.
 

 
Sun protection slats made of green laminated glass with 50% of their area covered in white dots.