New glamour for an industrial monument – an extended silo tower glazed in Pilkington Activ Suncool™
The old industrial area of Heilbronn, near the shoreline of the river Neckar, has recently been rejuvenated. After two years of construction work, the “Am Kaiser’s Turm” (AKT) building is now completely renovated. Its architecture is impressive, making it a key feature of the new Neckarpark. This industrial monument was extended with new buildings, whose service and retail companies are bringing new life to the area. An “eye catcher” is the glass cube on top of the 30 metre high silo tower. The glass used for the cube is Pilkington Activ Suncool™ self-cleaning solar control glass.
The AKT was already a major landmark throughout the city. The top of the 30-metre-high main building features an illuminated red “Kaiser’s” commercial sign, which has long been a feature of the Heilbronner industrial area. Built in the period 1936–1939, the tower was originally surrounded only by a three storey industrial building with a delivery area. The constructor was Josef Kaiser, son of the founders of the eponymous supermarket chain. Up until 2001 the old industrial building was used by the Tengelmann Group, Kaiser’s parent company, for administration and storage.
Inspiration from “Neckar pebbles”
After an in-depth study on the redevelopment of the area, the decision was taken to commission the Heilbronn office of Müller Architects. They proposed a plan that envisaged a tripling of the base area of the existing building to around 14,500 m². The proposal included the addition of a new structure to the existing steel-concrete-clinker building, with two different sized, two-storey high ellipses. The architects took inspiration from the pebbles in the river Neckar, the organic forms of which are intended to give a counterpoint to the existing Bauhaus-architecture building. The ellipses are combined by a glass construction on the top floor and a membrane construction on the first floor on top of the patio.
The ellipses are of monolithic design, with flat slab, steel-concrete-stilts and combined carrier. Before construction work could start, extensive excavations, down to the level of the Neckar pebbles was required. The architects decided to use sheets of raw aluminium for the outer skin, which bends around both ovals and which, when the sun shines, are reminiscent of shiny pebbles in the water.
Crowning Glass cube
The architects have used an 8-metre-high, two-storey glass cube for the silo tower, with a steel-glass-façade, providing for a panorama restaurant and an impressive view on Heilbronn. The cube is surrounded by a glazed construction with filigree bars. The objective was to achieve a perfectly flat glass cube with frameless transverse air conditioning. Night time illumination is provided by special RGB-controlled lighting around the inside of the façade. The system makes it possible to display a range of colour scenarios and to dim the lighting at the same time. The entire interior lighting system is based on light emitting diodes, which generate very little heat and consequently do not impose an additional load on the air conditioning system.
State of the art functional glazing
The glass used provides both aesthetic appeal and functionality and the resulting neutral glazing preserves the essential qualities of the original listed industrial building. From the functional point of view 1.5 by 3.5 metre windows combine a couple of features. Pilkington Optilam™ 12,8 was used on the interior in order to meet all the requirements for occupant safety. The required maximum 40 per cent total solar heat transmission is achieved through the use of the two solar control products, Pilkington Activ Suncool™ 70/40 and Pilkington Activ Suncool™ Neutral 53/40*. Another feature is the self-cleaning properties of Pilkington Activ™ coating. The product features a special coated surface, which works in two stages: using a “photocatalytic” process, the surface reacts with ultra-violet rays from natural daylight to break down and disintegrate organic dirt. The second part of the process happens when rain or water hits the glass. Because Pilkington Activ™ is “hydrophilic,” instead of forming droplets the water spreads evenly over the surface, and as it runs off takes the dirt with it.
Compared with conventional glass, the water also dries off very quickly and does not leave unsightly “drying spots.” The owners of the building save money, because the glass does not have to be cleaned so often, and the occupants are able to enjoy their view of Heilbronn and its surrounding vineyards.
* Pilkington Activ Suncool™ Neutral 53/40 is not manufactured any more.