Sustainable Cities™

Frankfurt: Harmony between humans, nature... and computers

Many people regard the Commerzbank Tower in Frankfurt am Main, Germany, as the mother of all ecological skyscrapers. However, it seems the children can still learn a few lessons from their mother. In a decade where a lot of attention is given to technologies such as solar panels, biomass burners, and wind turbines, designers and planners have perhaps neglected one of the most powerful technologies at their disposal – the computer.

Toppen af Commerzbank Tower med udsigt over Frankfurt, 22. April, 2007, af Chaouki, Flickr Creative Commons

Thinking back to the 1990's, some may recall a time of incredible excitement when visions of cyberspace were suddenly fulfilled and designers began fusing the worlds of electronic technology with the built environment. This former time represents the generation of the Commerzbank Tower, the world's first ecological skyscraper. Erected in Frankfurt, Germany, the building was originally commissioned in 1991 and was completed in 1997. The architecture firm Foster and Partners designed the Commerzbank Tower without the solar panels or renewable energy technologies that many ecological skyscrapers possess today. However, the tower has a number of truly remarkable characteristics with regard to the blossoming computer technology of the time and its integration into the built environment.

Nearly all of the building's internal environment-regulating systems are linked to one 'smart' computer. This computer regulates the cooling system by monitoring the flow of cool water through pipes in the ceiling. It also controls the heating system by permitting or prohibiting the use of the conventional radiators near the windows of each office. Perhaps most importantly, the ventilation system uses the computer to switch between air circulation induced by the building's cooling/heating systems and natural ventilation from the opening of specially-designed windows. When the weather is suitable, the heating/cooling system automatically closes down and a green indicator light, located on a panel in every office, signals that the normally-locked windows can be opened. Thanks to a protective outer layer of glass, these windows can be safely opened in high winds, driving rain and even on the highest floors of the building. The green light displays for roughly a third of the days of the year and helps Commerzbank use 25-30% less energy than buildings of comparable size.

Window and heating/cooling ventillation strategies used in the typical office, Copyright Foster Partners

The central computer gathers information from multiple sources throughout the building. Nine weather stations monitor solar radiation, air temperature, air pressure, and wind speed from each of the building's sides at varying heights. All of this is compiled into the intelligent algorithm system of the building's computer, which uses trial and error to decide when to switch modes. In this way, the computer helps determine the optimal balance between human comfort and energy efficiency. The building also has features that gather information about the presence or absence of people in the building's rooms. For example, sensors are used to determine whether an electric light should be switched on or off.

Looking at the Commerzbank Tower today, one can notice a bit of a shift in the technologies that sustainable architecture designers were fascinated with over the past two decades. While the computer seems to have developed immensely as a tool for communication between people in this time, it seems to have developed less as a tool for communication between people and their environment or between one aspect of the environment and another. Commerzbank illustrates the huge potential of technologies that communicate in such a way that have perhaps received less attention recently but are nevertheless very reliable and useful.

Sky gardens

The Commerzbank Tower has also been known for its innovations in terms of indoor gardens. Occurring at each of the 9 levels where the aforementioned weather stations are located, the "sky gardens" are each four stories tall and take up one of the three sides of the building's triangular plan. These green oases spiral up the building, each facing a different direction as one ascends. Additionally, they possess different vegetation depending on the direction they face; the East side displays Asian vegetation, the West side exhibits North American, and the South side shows Mediterranean.

The gardens have done a lot to improve the indoor air quality in terms of oxygen content and humidity but perhaps their most important dimensions is a social and psychological one. The gardens act as a gathering area for workers to meet people from other departments or who just need a break to recharge their working minds. Also, the offices in the other two sides of the triangle face the gardens and act as a constant source of natural scenery. They also let a lot of natural light into the core of the building and illuminate the inner offices with sunlight. As a result of this, a noticeable increase in worker efficiency has been observed by many individuals who transfer to the Commerzbank Tower.

Last updated Tuesday, January 21, 2014