Geothermal heat extractor

A geothermal heat extractor comprising:

• a heat transfer fluid;
• a heat transfer fluid supply conduit, the heat transfer fluid being maintained in the heat transfer fluid supply conduit in a liquid state at a pressure above its saturation pressure;
• a heat transfer fluid return conduit;
• a geothermal heat source coupled to the heat transfer fluid return conduit;
• at least one flow control valve configured to control the flow of the heat transfer fluid from the heat transfer fluid supply conduit to the heat transfer fluid return conduit to limit the pressure within the heat transfer fluid return conduit below the saturation pressure of fluid vaporized therein;
• and
• an external load coupled to the heat transfer fluid return conduit,
• wherein as the heat transfer fluid is provided to the heat transfer fluid return conduit in the liquid state, the heat transfer fluid vaporizes in the heat transfer fluid return conduit by heat supplied to the heat transfer fluid return conduit from the geothermal heat source, and
• wherein the vaporized heat transfer fluid is supplied from the heat transfer fluid return conduit to the external load.