The Potsdamer Platz project was supported by experts in construction ecology right from the start. An ecological concept was developed and implemented covering both the period of construction as well as the operation of the buildings following completion. Construction materials were chosen with due consideration of health and environmental aspects; energy consumption and the emission of pollutants were minimized. A key feature of the construction phase was the implementation of the construction logistics concept through the establishment of the "Baulog" company and the delivery of all construction materials by rail. This kept noise and air pollution for the people of Berlin to a minimum.
All buildings are heated and cooled by "Heizkraftwerk Mitte". This is a modern and environmentally friendly power-heat cogeneration plant. The buildings are cooled without the use of energy-hungry air-conditioning units. All windows can be opened. The offices have a sophisticated ventilation and facade system that makes optimal use of temperature fluctuations at different times of the day or the year. The heat-storage properties of reinforced concrete are exploited, thus reducing temperature fluctuations inside the buildings. In rooms with higher cooling requirements, the temperature is regulated by cooling ceilings in which cold water circulates.
Some of the higher buildings have double frontages for better climate compatibility. Outer glass surfaces adjust to the current weather situation to reduce the effects of wind and noise, but let light and fresh air through to the actual windows. The use of this style of construction saves around 50% of primary energy compared with air-conditioning equipment. Due to the holistic approach of these measures, carbon-dioxide emissions were reduced by 70% compared with conventional construction methods.
The buildings’ roofs are used to collect rainwater. The 19 buildings have a total area of 50,000 square meters, on most of which grass or other plants grow. The rainwater is stored in three large cisterns, and covers part of the requirements of the lakes and the toilets in the buildings. As a result, approximately 20 million liters of drinking water are saved each year.
