Built Expressions Bangalore :: Commerzebank Tower, A Sustainable Obelisk

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Commerzebank Tower, a sustainable obelisk

Commerzbank Tower, head office of Commerzebank, a leading bank in Germany and Poland is an outstanding architectural landmark of the financial capital Frankfurt. This remarkable building, designed by Lord Norman Foster, founder and chairman, Foster+Parnters has been a feature on Frankfurt's skyline since 1997 and is considered an excellent example of environmentally-friendly and energy-saving architecture.

When construction completed on the 53-story Commerzbank Headquarters in 1997 it set out as the tallest building in Europe, but what made it innovative, was its combination of form, ingenuity and technical expertise to create an entirely new building type: the humane and socially responsible skyscraper. The Commerzbank Tower has air conditioned structures with a central service core and identical, spatially separated floors; Commerzbank tower is flooded with daylight and naturally ventilated, has a full-height atrium, and four-storey landscaped gardens evenly distributed over

the height of the building. Working in combination, these architectural elements unlock the internal space of Commerzbank, transforming the entire work environment.

While Commerzbank Tower has a distinctive presence on the Frankfurt skyline, it is also fastened into the lower-scale city fabric, with restoration and rebuilding of perimeter structures reinforcing the original scale of the block. The developments at street level provide shops, car parking, apartments and a banking hall, and forge links between the Commerzbank and the broader community. At the heart of the scheme is a public galleria with restaurants, cafes and spaces for social and cultural events.

Considered to be the world's first ecological office tower, Commerzbank Headquarters relies heavily on passive strategies to create a pleasant work environment for its occupants. These strategies include a triangular (doughnut) floor plan, sky gardens, and a full-height atrium that allows for every office in the tower to have operable windows for views, natural ventilation, and daylight. The four-storey sky gardens (which spiral up the sides of the tower) provide fresh air and allow for passive solar gain, while the central atrium space acts like a natural ventilation chimney for the inward-facing offices. A computer controlled building management system decides whether passive or active systems are most appropriate for use at a given time and adjusts openings and shading devices accordingly. Commerzbank tower also uses water, instead of air, to condition the building, which saves a tremendous amount of energy over the life of the building.

Green Building Frankfurt

The Commerzbank tower was well ahead of its time when it was built, and not just architecturally. The tower, which has been a landmark on the Frankfurt skyline ever since, is also a leading example of environmentally-friendly and energy-saving architecture. Commerzbank received the ‘Green Building Frankfurt’ award in 2009 in recognition of the building's pioneering role.

A feature that makes the building unusual throughout the world is its framework construction, which allows the integrated tower gardens to be stretched over the upper levels without support. Each of these ‘green lungs’ features a different type of vegetation (Mediterranean, Asian, etc.).

At the same time, the gardens are part of a special ventilation system; a double-shell climate façade encloses the glass tower. Through openings in the outer shell, fresh air enters the space in the façade, while the windows of the

inner shell can be closed or opened individually by the employees. One of the main reasons as to why Commerzbank Tower is considered to be the first “ecological skyscraper” is that passive strategies are utilized at all scales ranging from window detailing to the full-height atrium. Typically, modern office buildings full of heat-producing machinery have a higher demand for cooling, but Frankfurt winters typically require heating as well.

Commerzbank has multiple other systems in place to lower energy consumption and improve its sustainability. With the building’s high insulation quality and abundance of glazing, heat is provided through 3 conventional radiators located at the sides of the windows. The cooling system, however, is far more innovative. Cool water – absorbed through environmentally friendly refrigerating machines attached to municipal streams - is pumped through tubes in the ceiling panels and cools the building down without resorting to energy-intense air conditioning. Water has a high capacity for absorbing heat and moving it around uses less energy than circulating air, which needs to be constantly replaced.

Facts

Official Name: Commerzbank Tower

Country : Germany

City: Frankfurt

Building Function: Office

Structural Material: Composite

Start of Construction: 1994

Completion: 1997

Global Ranking: #173 tallest in the World

Regional Ranking: #6 tallest in Europe

National Ranking: #1 tallest in Germany

City Ranking: #1 tallest in Frankfurt am Main