The resulting city heat island in Herdern Areal is used to maintain a windtower that works in both directions: by day as solar chimney, sucking warm air from the street level; by night as windcatcher that traps the cool west wind and brings it down to the street. In combination with an enormous de-sealing of the ground floor area, a change of the PET temperature of -5° C can be expected, allowing not only comfortable temperatures for pedestrians but also for the workers of Engros.In combination with solar power, the mere windtower offers itself as an energy hub, that can as well serve as energy reservoir. Sunlight is converted into power through Photovoltaic panels, placed on all sides of the tower. It is saved in form of warm water that is stored in a 1`000 m3 warm water reservoir inside the tower.
