A switch is not absolutely necessary to light up a room. It is perfectly possible without – as Nimbus demonstrates in the new building of the Neckar-Fils regional arm of the Südwestmetall employers' association in Esslingen. The light activates itself autonomously – but only when necessary – in this markedly transparent building with its sweeping form. The architect was also convinced by the formal aspects of the Nimbus luminaires.
We are often surprised to find that a difficult piece of building land need not present an obstacle to outstanding architecture. Esslingen am Neckar is a case in point. Not far from Stuttgart, in the booming Mittlerer Neckar region, Esslingen is currently undergoing a transformation in terms of urban planning, whereby the former rail freight station and the adjoining industrial land are being redeveloped. To the west, this large area ends in an enclosed triangle – between the railway line, road and steep wine terraces. Clearly not a simple situation, but it did not prevent fritzen 28, a local firm of architects, fromconstructing a remarkable building that takes the client's specific requirements and the local framework conditions as the basis for an autonomous architectural and energy concept.
EFFICIENT ENERGY AND LIGHTING SYSTEMS
A heat pump draws energy for heating and cooling from a groundwater well; activated and largely unpanelled ceilings take on the task of regulating the room temperature. The mechanical displacement ventilation developed and simulated in collaboration with Transsolar introduces outside air through the cavity floors; the windows can be opened manually; used air is evacuated through the atrium via heat exchangers. In combination with the shading system and triple glazing, the lighting system helps to considerably reduce cooling loads, as it is based entirely on LED luminaires with a power requirement equivalent to just six watts per square metre of usable floor space. This value is achieved in part through the usage-based and daylight-related control of the lighting. Not only the luminaires but also the innovative light control system comes from Nimbus, the Stuttgart-based LED pioneer.
WIRELESS IQ – VERY SLIM CONTROLLER Suspended, round discs from the Modul R Project family spectacularly illuminate the atrium throughout its entire height. The LED discs from the Modul R Project range can even be found in those parts of the atrium in which, for acoustics reasons, suspended ceilings were installed. All of these luminaires work with light sensors that adjust the illuminance in relation to the level of ambient light – decentralised for individual groups of luminaires.
The controller can be so slim thanks to "Wireless IQ", a wireless interconnection developed by Nimbus based on the Zigbee standard. The offices in particular show just what this innovative Nimbus technology is able to do The light is automatically activated there whenever the presence sensor in the Modul Q Project ceiling luminaires detects that a person has entered. The ceiling luminaires then switch on without any delay and also send a radio signal via "Wireless IQ" to the "Force One Power" floor-standing luminaire at the workplace, which then brightens up to 50 percent output. When the employee approaches the floor-standing luminaire, it dims up to the individually set lighting level. Thanks to the integrated radio technology (Wireless IQ) and sensor system, the Nimbus ceiling luminaires can be collected into so-called "virtual groups" or "light clouds" depending on the specific requirement and usage profiles. The communication between floor-standing and ceiling luminaires is a real first.
If the proportion of ambient light in the room goes up or down, the sensor of the floor-standing luminaire detects the change, adjusts the target illuminance accordingly and also controls
the group of ceiling luminaires. And as long as the employee is working under the Force One and is detected by the presence sensor, the ceiling lighting naturally remains at a constant level. The employee can make his or her own individual changes at any time – using the sensor buttons on the "Force One Power". Once again, the ceiling luminaire will adjust to the settings selected on the floor-standing luminaire. The grouping of individual luminaires programmed in the software determines which luminaires communicate with one another to form a "light cloud".
DOING AWAY WITH SWITCHES AND CABLES
"Wireless IQ" also means that traditional light switches and cables are no longer needed – being free of fixed-positionelectrical fittings makes it easier and less expensive to carry out organisational changes or to use spaces for a different purpose. And as employees can easily override the settings, "Wireless IQ" enjoys a very high level of acceptance in Esslingen. Another reason is the fact that there is practically no delay in the switching process – after all, nobody wants to enter a darkened area, neither on the stairs nor in corridors. Of course, the building is not entirely without switches. In meeting rooms they are used to call up various lighting scenarios for presentations and different types of room usage. But even these switches are based on the Zigbee wireless standard and do not require a fixed position electrical fitting.
ANALOGOUS TO THE ARCHITECTURAL PRINCIPLE
It was not only energy-efficiency, convenience, flexibility and the simple control system that convinced the architects and clients to opt for Nimbus LED luminaires. "The formal aspect was also important to us. First of all, the slim luminaires fit in perfectly with our layers principle, and secondly we were able to stick to the same design idiom throughout the whole building," explains Katrin Kussina from fritzen 28. The architectural concept obeys the principle of horizontal layering; the floor plan of every storey has a different shape, receding in some places, jutting out in others. "It is intended to establish an analogy between the building and the wine terraces," adds Hansjörg Schwarz from fritzen 28. It is a lively, amorphous blurring of the floors into one another; towards the east, where future developments are planned, the motion abates, but otherwise "no points lie directly above one another"
INVITING GESTURE
The envelope of the elongated building boasts another distinguishing feature: it has been designed for a high degree of transparency. The space between the white bands of the mighty ceilings of the individual floors is filled with almost nothing but glass – in line with the client's wish for a communicative, open building. After all, the building commissioned by the metal industry employers' association is not merely a classical administration building. There are indeed offices behind glass partitions, but basically the building serves as a forum for events and provides members with rooms for meetings and consultation.
That is the reason for the large empty space that penetrates all levels, connects them with a wide staircase and constitutes a grand, inviting gesture. From here, visitors can make their way to the large conference room on the ground floor, to the smaller multi-media meeting rooms above or to the various offices. Wherever visitors happen to be, they can gain an impression of the building's framing, and different visual perspectives arise towards both the interior and exterior.
