El Commerzbank, con sus 53 plantas de altura, es el primer rascacielos de oficinas ecológico del mundo y el edificio más alto de Europa. El proyecto planteaba explorar la naturaleza de la torre de oficinas y concebir nuevas ideas sobre su utilización y aprovechamiento ecológico. Un aspecto central de este enfoque es la apuesta por los sistemas de iluminación y ventilación naturales. Todas las oficinas cuentan con luz natural y con ventanas practicables, que permite a sus ocupantes controlar su propio entorno laboral. El resultado es un edificio con unos niveles de consumo energéticos equivalentes a la mitad de los de una torre de oficinas convencional.

El edificio presenta una planta triangular compuesta por tres «pétalos» (las plantas de las oficinas) y un «tallo» formado por un atrio central de altura completa. Los jardines de invierno ascienden en espiral alrededor del patio y se convierten en el foco visual y social de los grupos de oficinas de cuatro plantas. Desde el exterior, estos «jardines en azoteas» otorgan al edificio sensación de transparencia y ligereza. En términos sociales, vendrían a representar el papel de la plaza del pueblo de cada grupo de oficinas y proporcionan un lugar para reunirse con los colegas y relajarse durante las pausas. En términos ambientales, los jardines aportan luz diurna y aire fresco al atrio central, que sirve como «chimenea» de ventilación natural a las oficinas orientadas hacia el interior. En función de la orientación del  jardín, se ha seleccionado vegetación oriunda de tres regiones: Norteamérica, Asia o el Mediterráneo.

La torre posee una presencia característica en el perfil urbano de Fráncfort, aunque también se integra en el tejido urbano de menor escala mediante la restauración y una reconstrucción apropiada de las estructuras perimetrales para reforzar la escala original de esta manzana de la ciudad. Estos edificios acogen comercios, zonas de estacionamiento, apartamentos y un banco, y ayudan a forjar lazos entre el Commerzbank y la comunidad circundante. En el corazón del proyecto reside una galería pública con restaurantes y cafeterías, además de espacios para actos sociales y culturales. La galería se ha convertido, además, en una concurrida calle peatonal. Curiosamente, el día de la inauguración del edificio del Commerzbank, el Financial Times lo adoptó como símbolo de Fráncfort, al igual que había hecho con el Parlamento y la Torre Eiffel como símbolos de Londres y París, respectivamente.

Bocetos y dibujos

Desarrollo

Construcción

Sostenibilidad

Site + Climate

The building design responds to prevailing winds and solar orientation, to ensure optimum ventilation and daylight penetration.

Form + Massing

The triangular shape and central atrium assisted in the creation of a zone of negative pressure, that drives natural ventilation through the building.

Passive Design

The building was designed to be naturally ventilated for 60% of the year, with the sky gardens allowing natural ventilation during shoulder seasons. This approach was expected to reduce energy consumption by up to 50% compared to an equivalent air conditioned office.

Environmental Systems

Cooling is provided by chilled ceilings, while heating is from perimeter heating. Windows are connected to the BMS to ensure that the mechanical ventilation only works when the windows are closed. Artificial lighting is connected to motion sensors and timers.

Renewable Energy

From 1st January 2008, the Commerzbank Tower has been supplied exclusively with green energy that is derived from renewable energy sources.

Mobility + Connectivity

The central infill site location of the project, is also key to its connectivity and access as it is close to public transport links.

Materials + Waste

The development reused and restored the existing perimeter buildings which reduced materials consumption. Even before the existence of the Forestry Stewardship Council, all timber used in the building was taken from managed sources. Operational waste segregation facilities are provided and catering waste is composted.

Water

To reduce potable water consumption, the condensate from the chillers was recycled, and used for WC flushing

Land + Ecology

Large sky gardens with a diverse ecological profile were used to provide informal break out spaces with views of the city. This incorporation of landscaping, and the other sustainable design responses, led to Commerzbank being dubbed as the world’s first ‘ecological office tower’.

Culture + Heritage

The tower, built in the centre of Frankfurt, was designed with respect to existing historical structures and the buildings surround. The project reused and restored the existing perimeter buildings of the site, which helped to maintain the streetscape.

Wellbeing

Designed with the end user in mind, office areas are naturally ventilated and flooded with daylight. Users can regulate their own environments and sky gardens act as a breakout space.

Prosperity

The tower has been embraced by the city, and Commerzbank is now regularly shown as an iconic structure of Frankfurt, and the German stock exchange.

Planning for Change

As the first ‘ecological office tower’, the sustainable approach for the project was ahead of its time. The design planned for a future of increasing resource scarcity and cost, by minimising energy and water consumption, whilst providing solutions for enhanced comfort.

Performance in Use

Post occupancy studies have shown that the tower actually consumes 20% less energy than predicted, and there has been a year on year reduction in energy consumption since 2000. This is largely because the building users have extended the period of natural ventilation up to 85% of the year, as opposed to the 60% designed for.

Cita

"We now have five years' experience of running the building

and I am very happy to report that it is actually far more efficient in energy terms than was anticipated at the design stage. For example, whereas it was estimated that the building would be naturally ventilated for 60 per cent of the year, we are in fact able to use natural ventilation for more than 80 per cent of the time. This means that our present electricity usage is approximately 20 per cent less than predicted. As you might imagine, we are very happy."Peter Muschelknautz, the Commerzbank Facilities Manager 2002 "We now have five years’ experience of running the building, and I am very happy to report that it is actually far more efficient in energy terms than was anticipated at the design stage. For example, whereas it was estimated for 60 per cent of the year, we are in fact able to use natural ventilation for more than 80 per cent of the time. This means that our present electricity usage is approximately 20 per cent less than predicted. As you might imagine, we are very happy."Peter Muschelknautz, The Commerzbank Facilities Manager 2002 "We are given lots of praise when our office workers leave at night and tell us that they don't feel tired - this means that their productivity increases. This is more important to me than great architecture or sky gardens."Dr Horst Gruneis, director of Commerzbank's Central Building department quoted in Architectural Record, January 1998 "At last we can open the windows whenever we like, we can feel the air and the noises of the street - we feel freer."Unnamed Commerzbank employee quoted in Frame 1, December 1997 "As the interiors of Foster’s Commerzbank come together, the most striking effect is one of glistening transparency." Barrie Evans, The Architects’ Journal, 27 March 1997 "This architecture speaks of a better world – on the one hand, highly technical; on the other, ecologically defensible."Manuel Cuadra, Domus, November, 1997 "At last we can open the windows whenever we like we can feel the air and the noises of the street – we feel freer." Unnamed Commerzbank employee, quoted in Frame, 1 December 1997 "You sense that a kind of community has been created, one that could become familiar and intimate, so unlike the usual downtown tower."Mary Pepchinski, Architectural Record, January 1998 "With the Commerzbank we combined an ambitious structural and aesthetic vision with a quest for natural ecological solutions and the well-being of the individual. For me, it is in this synthesis of these themes that the real achievement lies."Norman Foster

Datos y cifras

  • Adjudicación: 1991
  • Finalización: 1997
  • Superficie: 120 736m²
  • Altura: 298m
  • Capacidad: 2400
  • Cliente: Commerzbank AG
  • Ingeniero estructural: Ove Arup & Partners / Krebs & Kiefer
  • Supervisor de cantidades: Davis Langdon & Everest
  • Ingeniero de M+E: Roger Preston & Partners/ RP&K Sozietat GmbH/ Petterson & Ahrens
  • Arquitecto Paisajista: Sommerland & Partners
  • Ingeniero de iluminación: Lichtdesign

Premioss

  • Green Building Award of the City of Frankfurt
  • RIBA Architecture Award
  • Bund Deutscher Architekten - Martin-Elsaesser-Plakette Award
  • British Construction Industry Awards, International Award to

Características:

Winter gardens linked to a central atrium spiral up the tower to become the visual and social focus for four-storey clusters of offices.