Winners of StartUp-Impuls special Prize 2008

Innovations are worthwhile : At the award ceremony of the ideas competition StartUp-Impuls in 2008 drew the enercity fund proKlima particularly innovative approaches with the special " proKlima ". "We hereby acknowledge entrepreneurs and scientists who support them with new products and technologies a sustainable energy future," said Tobias Timm , Acting Managing Director of the enercity funds ...

... and the winner 2008 is: The sandwich tower with high-strength steel and composite materials for more stability and sustainabilit .

For this research and development work were Prof. Dr. -Ing. Peter Schaumann and Dr. -Ing.  Christian Keindorf by the Institute for Steel Construction Leibniz Universität Hannover awarded the 1st place. The scientists have developed a new tower concept in sandwich construction specifically for wind turbines. As an alternative to the existing tower versions they had to develop the idea of a sandwich tower. The difference to the previous steel towers is that the required thickness is divided into an inner and outer tube. This reduces the welding effort because this otherwise squared increases with the plate thickness.

The annular gap between the inner and outer tube is replenished from below in ascending order with a composite material, which not only stabilizes the steel sheets against the shell buckling, but also participates in the load transfer . In addition, the high-strength composite material serves as a force-transmitting element to the next tower section . This joining technique in the form of a tube-in-tube connection has also been investigated by the farmers steel and is referred to as a sandwich joint. This fatigue- critical annular flanges and a variety of maintenance-intensive screws can be saved between the tower sections.

By the sandwich principle, the stability and sustainability of towers can be increased , and that, although less steel is used for can also generally higher strength steels (eg S460 ) are at lower thicknesses used instead of the normal-strength steel grades (S235 and S355 ) by the higher stability . The fact is the tower easier despite additional composite material.

It can, however, say more benefits. Since the sandwich tower consists of longitudinally oriented individual subshells, the limited headroom is maintained with bridges. It can therefore be towers built with larger diameters and transported over land.

Overall, larger towers can be realized with the technical innovation, bringing the energy output of the wind turbine increases disproportionately. The higher costs for the production and assembly of the sandwich tower disappear after a few years. In addition, lower maintenance costs incurred and resource- intensive steel tonnages can be saved.

In the picture Prof. Schaumann (right) to detect and Dr. Keindorf (left) at the award ceremony. The prize money was gratefully completely as share capital in the construction of the SKI Ingenieurges. mbH invested.