Geothermal heat exchange installation and method

A geothermal installation for collecting heat, the installation including a fluid transport system comprising at least one fluid injection passage extending from a ground-level facility including a pumping station located at the Earth's surface to a depth below the Earth's surface such that energy collected can be applied usefully, the at least one fluid injection passage connected at said depth, respectively to an array of heat collector micro-tunnels that are adapted to allow a heat transfer fluid to circulate therein, and which:

• a) extend outwardly substantially horizontally in an essentially horizontal plane drilled and located in bedrock and passing through said depth,
• b) extend diagonally downwardly from an essentially horizontal plane drilled and located in bedrock and passing through said depth, or
• c) extend vertically downwardly from horizontally laid out collecting tunnels drilled and located in bedrock and formed in the essentially horizontal plane, wherein the micro- tunnels are connected with at least one fluid return passage which is adapted to return the heat transfer fluid or another heat transfer fluid to the facility, the fluid transport system adapted for the flow of the heat transfer fluid or the another heat transfer fluid therethrough to and from the facility.