Energy Efficiency & Glass Façade Magnificence: Stadttor (City Gate)

Introducing yet another architectural wonder that has allowed concrete, steel and aluminium to give way to glass, for its much talked-about aesthetic and functional benefits - Stadttor (City Gate) in Düsseldorf, Germany. This is a building with a double-skin glass façade that keeps the premises well-lit, cool, energy-efficient and so on.

Stadttor (City Gate)

Stadttor (City Gate) is the President’s office and the seat of the State Chancellery NRW. This building was designed by Petzinka, Pink & Partners. It encompasses aspects of traditional design and well as state-of-the-art energy performance capabilities.

This spectacular building consists of two rhombic parallel glass towers with 16 floors each, and 3 attic floors connected to one another. Two glass towers enclose a 56m high atrium in the centre, designed to allow maximum natural daylight - a citywide building ordinance. Also, each of the towers has a corridor with a double-skin façade, and a single-storey interstitial space that is 90-140 cm deep and 20-m long.

Glass Façade

The interior glass façade features double-pane, low-E glazed doors operable at every other bay. The exterior of the building follows the "structural glazing" principle. The exterior façade is 12-mm fixed safety glass. High-reflectance Venetian blinds are located in the interstitial space. At each story, a climate buffer corridor circulates fresh air between facades, allowing natural ventilation for 60% of the year.

Efficient Ventilation

The two gate towers are built in a way to give a full view of the surrounding environment to the building occupants. Each floor has a 750 m² surface. Thanks to its ventilating systems, new air-conditioning and double glass façade, there are 70% lower incidental expenses than conventional full air-conditioning. The facade inner space natural ventilation of the building creates a climatic shield and it definitely supplies fresh air throughout the office. During the summer, even the extreme heat does not affect the room temperature, owing to the cooling system which extracts cold air from soil.

Mechanical ventilation is provided during peak summer and winter hours. The building is capable of being naturally ventilated for 60% of the year.

The Stadttor’s mechanical systems are fully computerized, with 14,000 sensors located throughout the building to moderate and maximize energy efficiency. In winter months, the structure uses on-site recaptured heat as well as excess thermal heat produced by Stromkraftwerks, an electrical plant upriver on the Rhine. An on-site geo-exchange system supplements heating with ceiling-integrated radiant transfer that also serves the building’s cooling needs.

Long-lasting lighting systems that are centrally programmed have been fixed; these can also be manually controlled within work spaces. Natural daylighting, natural ventilation and humidity control provide optimum thermal comfort that enhances occupant experience as well as the building’s energy performance.