| Abstract |
Tunnels drain the rock zones located above them; as a result a considerable amount of warm water flows into the tunnels and subsequently to the portals. On accounts of its temperature this water cannot be released into nearby rivers without previously being cooled down, due to environmental regulation This energy reserve (drained hot water and heated air) can, however, be used at the tunnel portals for various applications. From Switzerland a whole suite of uses can be reported: space heating, greenhouses, balneology and wellness, fish farming (incl. caviar production). |