For a long time, Strasbourg's harbour district was inaccessible to residents and visitors, and in parts was more reminiscent of an industrial wasteland than a residential district. The city of Strasbourg saw this as a good reason to plan the redevelopment of the district in 2008. The idea behind the restructuring was to develop an environmentally friendly metropolitan area that creates better living conditions for existing and future generations using as little resources as possible. As the city takes the issue of sustainability very seriously, the entire waterfront was transformed into an eco-district. It was important for the city planners to create green areas, parks, playgrounds, cycle paths and encourage the use of local public transport - because less traffic improves air quality. But numerous shops and localities as well as living space for 650 people were also created in the new district Danube. One thing that all buildings have in common is that they were built as zero or low-energy houses. Even the first Plus Energy Tower was completed in 2018: The Tour Elithis Danube produces more energy than it actually needs.
Positive energy balance in the Tour Elithis Danube
A base area of 554 square metres, 17 floors with 60 flats, 900 square metres of office space and a roof terrace at a height of about 50 metres result in a total usable floor space of 4,500 square metres - this would be one way to describe the Tour Elithis Danube. Another would be to say that the high-quality sheet-metal cassette curtain wall elements sparkle in the sun. But beside all these facts and external elements, energy efficiency plays the most important role in the Tour Elithis Danube. Because one of the key goals was to construct a residential tower that produces all the energy it needs (zero power calculation). Thanks to its optimal facilities, the Elithis Tower even produces slightly more energy than is actually required: the building is aerodynamically constructed and has a highly insulating curtain wall. Both the roof and the south-facing curtain wall are equipped with a photovoltaic plant covering total of 1,233 square metres. The window and lifting-sliding door elements are made of aluminium and also have a highly insulating effect. These and other measures were important to the Elithis SAS engineering group, because it was their aim to make residents more aware of the principle of energy saving in everyday life. They wanted to show that living comfort is not achieved through energy waste. The generated energy is equitably distributed to the residents of the house; any surpluses are fed into the grid. The energy consumption can be monitored on specially installed screens. Residents who consume very little power can even earn a bonus on their bills for the first six years. As a result, it is also possible to present the Tour Elithis Danube as a genuine living concept of the future.
heroal systems for more energy efficiency
The metal works were carried out by the French metal construction company ATALU SAS. The aluminium systems supplier heroal supplied the system "The demands on building shells have dramatically increased in recent years. Modern, future-oriented projects such as the Elithis Tower place the highest demands on heat insulation, aesthetics and workmanship. These can only be achieved through strong partnerships," says Julien Rohmer, Managing Director of ATALU SAS.
Almost 300 elements of the heroal W 72 window system were used in the sheet-metal cassette curtain wall. Especially narrow view widths were important to the property developer - an individually adapted solution that blends in perfectly with the building shell. Thanks to highly thermally insulated composite profiles made of aluminium half-shells, polyamide insulating webs and a completely foamed insulation zone, the heroal W 72 window system achieves a Uf value of up to 0.93 W/m²K with a frame depth of just 72 mm. At the same time, the innovative web geometry makes the time-consuming and material-intensive use of frame and glazing rebate insulation unnecessary. The modular design leads to an optimal use of energy and materials and thus to maximum energy efficiency throughout the entire useful life. In order to offer the residents a special view of the newly landscaped harbour district, the roof terrace was also equipped with large glazed areas. 30 lifting-sliding elements of the heroal S 77 SL system were installed here.
To increase the air quality and therefore the quality of life of the inhabitants of Strasbourg, the port district was transformed into an eco-district. In this context the first Plus Energy Tower was completed in 2018, producing more energy than it consumes.