Newsletter - June 2010 - Issue 3
From the very outset of the preparations for the international urban planning and architectural design competition, it had been the stated aim of the European Central Bank (ECB) that its new premises should be 30% more energy-efficient than stipulated by the Energieeinsparverordnung 2007 (German energy-saving directive of 2007). Within the scope of that competition, it had laid down the spatial and functional specifications, as well as precise energy consumption requirements, in 2002. One of the key requirements was that of an integrated planning process, which meant that the architect had to work together from the outset not only with a structural engineer, but also with an energy and air conditioning designer in order to optimise the building’s energy efficiency and sustainability. The criteria of sustainability and optimal energy efficiency already had to be taken into account in the first drafts of the designs for the ECB’s new premises: economic, ecological and social aspects had to be weighed against the future cost of maintenance and repairs, as well as energy consumption. Throughout the competition and the subsequent tender procedure, great emphasis was placed on the design’s energy efficiency and on the needs of sustainability.
The resultant energy concept has the following features.
The Grossmarkthalle itself has a roof area of 10,000 m2. A system will be installed for collecting rainwater, so that it can then be used both to irrigate the gardens when there is not enough rain and to flush toilets.
The waste heat generated by the computer centre will be fed back into a ceiling heating system in order to heat the offices, as well as into the underfloor heating system of the Grossmarkthalle. The new ECB premises will moreover be connected to the energy-efficient combined heat and power system of the City of Frankfurt am Main.
The Grossmarkthalle’s surface areas, i.e. the roof and windows, will be insulated in order to create a thermal envelope between the outside and inside areas. The inside areas, such as the conference rooms, will have their own microclimate, as they will be integrated into the market hall as a separate house-in-house system.
Natural ventilation of office spaces
In addition to the central ventilation systems, motorised ventilation elements incorporated into the building facades will allow for the direct natural ventilation of the offices. As a result, individual fresh air requirements can thus be met as desired without the use of mechanical ventilation. People in the building will consequently also have more of an idea of what is going on outside.
Efficient solar protection and low-energy lighting
Highly efficient sun screens/glare shields will be integrated into the facades in order to prevent the buildings from absorbing too much heat from the sun.
Another way to save energy is to use natural daylight. The offices will be fitted with daylight sensors, so that the lights switch off automatically when there is sufficient daylight. In terms of the artificial lighting for the offices, as well as for the atrium and the market hall, there has been much research into ensuring that they are lit sufficiently and efficiently at all times of the day.
Use of geothermal energy for heating and cooling
In order to further reduce the energy costs of the building, geothermal loops were incorporated into the pile foundations, which descend about 30 metres until they hit Frankfurt’s bedrock. These loops can be connected to the water circuit and the heating pumps in the heating centre in order to extract heat from the ground in winter and coolness from the ground in summer.