Energy from earth-coupled structures, foundations, tunnels and sewers

Ground-embedded structures such as shallow foundations, bored piles, diaphragm walls, tunnel cut-and-cover walls, tunnel linings, anchors for NATM tunnelling and even sewer systems can be used as absorber elements for ground heat exchange. The technology is based on absorber pipes installed within concrete elements and a heat carrier fluid circulated through the system; heat is extracted from the ground or stored in the ground for heating and cooling of associated buildings. This promising technology leads to a reduction of fossil energy consumption at moderate installation and low operation costs. This paper describes some of the varied applications of the technology in Austria, ranging from the high-rise building Uniqa Tower in the city of Vienna to the Vienna metro extension U2 and, most recently, at the new 15 km long Lainzer tunnel at construction lots LT44 and LT32.