This is a method and apparatus for practicing the method, for the utilization of geothermal energy for the production of power, wherein a fluid (stream and/or hot liquid, or the like) from a geothermal aquifer is brought up the surface of the Earth through several wells of a group, and returned as condensate after passing through an energy extractor through another well, or wells of the group, and wherein a reversible flow arangement is provided whereby the fluid may be taken from different wells and utilized with the condensate going back through different wells successively and in turn by means of which salt deposits are eliminated, the heat of the aquifer is maintained, and maximum energy exraction is achieved.

For the exploitation of the geothermal energy in an active submarine volcano an elongated, substantially vertical, columnar concrete body is arranged above the orifice of the volcano so as to extend from the water surface vertically downwards through the water and into the magma in the orifice of the volcano so that the lower portion of the concrete body is submerged in the magma. The concrete body has such a displacement and such a weight that it floats in a balanced vertical position in the water and the magma. A coolant, preferably water, is circulated through internal cooling ducts or pipes in the concrete body from the upper end of the body downwards into the lower portion of the concrete body, which is submerged in the magma and where the coolant is heated by heat transfer from the surrounding magma, whereafter the heated coolant is returned through internal cooling ducts or pipes in the concrete body to the upper end thereof, where the heat content in the heated coolant is utilized.

The flow from geothermal wells is stimulated by injecting a liquid at selected levels in the well with the liquid having a boiling point below the temperature of the geothermal fluid at the levels of injection at the operating pressure at the levels of injection. The geothermal fluid and vaporized injected fluid from the well are applied to a system for extracting the heat energy as well as for cleaning sand and other well depositions that may accumulate in the geothermal well. The system may include a direct contact heat exchanger having either a vertical chamber or a horizontal chamber. The contactor has a plurality of zones including a boiler zone, one or more separation zones, and at least one heat exchange zone. The contactor may also include a wash zone and a flash zone. In the wash zone there is advantageously included recirculation trays vertically spaced for washing the vapor to remove entrained substances, such as minerals dissolved in the fluid from the geothermal wells. The recirculation trays include a manway for ease of access and service. The vaporized fluids from the contactor are passed through a power extracting gas expansion device, with the composition of the vapor being controlled to maximize the power extractable by the gas expansion device.

An isothermal heat pipe system for transferring heat from a primary fluid, such as geothermal water or steam, municipal water system, solar heated water, or the like, to another medium to be heated isothermally, such as a road or bridge deck surface, includes an elongated enclosed chamber with a volatile liquid, such as ammonia or freon, contained therein, a heat exchanger tube positioned to run through the chamber in contact with the volatile liquid, and elongated distribution pipes connected in fluid-flow relation to and extending upwardly from the upper portion of the common chamber above the level of the volatile fluid and extending into divers portions of the medium to be heated in spaced-apart relation to each other in such a manner that there is a continuous downward gradient in each of the distributor tubes from the distal end thereof to the chamber. The primary heated fluid is circulated through the heat exchanger tubes, and a wick material is attached to the external surface of the heat exchanger tube to increase surface area for transfer of heat from the heated primary fluid in the heat exchanger tube to the volatile fluid in the chamber around the heat exchanger tube.

Apparatus and method for recovering resources from subterranean rock formations, particularly heat energy, and more particularly geothermal energy. A heat-drill, which has means associated therewith for removing some rock from the earth and forming other rock into shafts, drills into the earth and forms two shafts at the same time. Both shafts communicate with each other and with the surface and are used to circulate a drilling mud which passes through the drill body and carries off the rock being removed. The heating means is shaped in a coil or grid pattern and operates at a temperature well above the melting point of the rock, heating the rock it displaces to well above its melting point, while raising the average temperature of the total rock melted to slightly above its melting point. The drilling mud absorbs heat as it circulates and the absorbed heat is put to any desirable use, particularly by being recovered from the drilling mud by a heat-exchanger on the surface. The drill has means associated therewith for automatically controlling its rate of advance into the earth and its general downward direction. The drill has means associated therewith for preparing the shafts, particularly the downflow shaft, for a particular type of fracturing of the surrounding rock formations to facilitate the collection of heat therefrom. Later heat recovery is facilitated by forming convection cells within the factures which encourage circulation of fluids at a distance from the shafts.t