A refrigeration appliance includes a refrigeration circuit having a condenser and a heat circulation system for heating an element of the refrigeration appliance. The heat circulation system includes a heat conducting region. A heat exchanging element includes the condenser and the heat conducting region. The condenser and the heat conducting region in the heat exchanger element are thermally coupled in order to output heat from the refrigeration circuit to the heat conducting region of the heat circulation system.

An underground heat exchanger has a bottomed tubular flexible bag body accommodated in an accommodation hole portion in the ground, and an outer tube accommodated in the accommodation hole portion, vertically extending along an outer surface portion of the bag body and communicating in its lower end with a lower end of the bag body. The outer surface portion of the hardening resin bag body can cover an inner wall portion of the accommodation hole portion in a closely contact state with the bag body being inflated. The bag body is hardened in the covering state, a lining tubular body formed by the hardening can form a liquid storage tank for storing a heat medium liquid in its internal space, and the outer tube is pinched between the outer surface portion of the bag body and the inner wall portion.

A plant for exploiting geothermal energy by circulating water or another fluid through a non-porous geological formation at a substantial depth below the earth surface, comprising multiple heat absorbing/production holes penetrating the said formation, with a total length of several kilometers and spaced more than 50 m apart. The production holes are connected to the surface by one single combined supply and return hole in which upward and downward flow is separated by a pipe comprising an insulating material and a seal. At the given positions of the common supply and return hole manifold zone designs connect the hole to the multiple production holes. The supply and return holes and production holes are closed circuits for transport of a fluid such as water through the said formation. A method for designing and establishing the plant is also disclosed.

The invention relates to a thermal energy storage having a fluid source comprising one or more primary boreholes (110; 210; 311, 312, 313; 411, 412, 413; 511; 611; 711; 811; 911) extending from ground level to a predetermined depth in a rock body; and one or more secondary boreholes (120; 220; 751; 851; 951) located remote from the fluid source. At least an upper and a lower fracture plane (P.sub.1, P.sub.2, P.sub.3) intersects the one or more primary boreholes (110; 210; 311, 312, 313; 411, 412, 413; 511; 611; 711; 811; 911) and said secondary boreholes (120; 220; 751; 851; 951), which fracture planes (P.sub.1, P.sub.2, P.sub.3) permit a hydraulic flow of fluid between the primary borehole and at least one of the secondary boreholes (120; 220; 751; 851; 951). The fluid source comprises a well system comprising at least two wells (311, 312, 313; 431, 432, 433; 531, 532, 533; 631, 632, 633; 731; 831, 832, 833; 931) where each well is in fluid communication with one or more fracture planes; and where at least one sealing element positioned to prevent hydraulic flow between wells. The hydraulic flow in each well is controllable to permit a hydraulic flow of fluid between one or more primary boreholes (110; 210; 311, 312, 313; 411, 412, 413; 511; 611; 711; 811; 911) and at least one of the secondary boreholes (120; 220; 751; 851; 951) in at least one fracture plane (P.sub.1, P.sub.2, P.sub.3).

The present disclosure describes a system and a method for generating energy from geothermal sources. The system includes an injection well and a production well extending underground into a rock formation, a first lateral section connected to the injection well and a second lateral section connected to the production well, the first and second lateral sections connected with a multilateral connector, defining a pressure-tested downhole well loop within the rock formation and in a heat transfer arrangement therewith. The downhole well loop cased in steel and cemented in place within the rock formation. The downhole well loop to receive working fluid capable of undergoing phase change between liquid and gas within the downhole well loop as a result of heat transferred from the rock formation. The system also includes a pump to circulate working fluid, a turbine system to convert the flow of working fluid into electricity, and a cooler.

The present disclosure describes a system and a method for generating energy from geothermal sources. The system includes an injection well and a production well extending underground into a rock formation, a first lateral section connected to the injection well and a second lateral section connected to the production well, the first and second lateral sections connected with a multilateral connector, defining a pressure-tested downhole well loop within the rock formation and in a heat transfer arrangement therewith. The downhole well loop cased in steel and cemented in place within the rock formation. The downhole well loop to receive working fluid capable of undergoing phase change between liquid and gas within the downhole well loop as a result of heat transferred from the rock formation. The system also includes a pump to circulate working fluid, a turbine system to convert the flow of working fluid into electricity, and a cooler.

A system and method of harvesting geothermal energy in a subterranean formation includes providing an injection wellbore that extends into the subterranean formation, positioning a plurality of selectively opening sleeves in the injection wellbore spaced apart the subterranean formation, providing at least one producing wellbore that extends into the subterranean formation in a predetermined location proximate to the injection wellbore, and fracturing the subterranean formation in a plurality of locations proximate to the plurality of selectively opening sleeves to enhance a fluid pathway between the injection wellbore and the at least one producing wellbore. Fluid is injected down the injection wellbore at a first temperature, and the fluid is produced from the at least one producing wellbore at a second temperature higher than said first temperature.

A system and method of harvesting geothermal energy in a subterranean formation includes providing an injection wellbore that extends into the subterranean formation, positioning a plurality of selectively opening sleeves in the injection wellbore spaced apart the subterranean formation, providing at least one producing wellbore that extends into the subterranean formation in a predetermined location proximate to the injection wellbore, and fracturing the subterranean formation in a plurality of locations proximate to the plurality of selectively opening sleeves to enhance a fluid pathway between the injection wellbore and the at least one producing wellbore. Fluid is injected down the injection wellbore at a first temperature, and the fluid is produced from the at least one producing wellbore at a second temperature higher than said first temperature.

The disclosed technology includes methods of extracting geothermal energy, generally comprising the steps of: insertion of a thermal mass into a Heat Absorption Zone, absorbing heat in thermal mass, raising the thermal mass to a Heat Transfer Zone, and transferring the heat from the thermal mass. The acquired heat can be used to generate electricity or to drive an industrial process. The thermal mass can have internal chambers containing a liquid such as molten salt, and can also have structures facilitating heat exchange using a thermal exchange fluid, such as a gas or a glycol-based fluid. In some embodiments, two thermal masses are used as counterweights, reducing the energy consumed in bringing the heat in the thermal masses to the surface. In other embodiments, solid or molten salt can be directly supplied to a well shaft to acquire geothermal heat and returned to the surface in a closed loop system.

This invention provides a method of extracting geothermal energy, comprising providing salt into a well shaft that ends in a chamber in the Earth surrounded by a source of geothermal energy. The salt melts and heats up to the temperature within the chamber. The hot molten salt is then extracted, and the heat from the molten salt is used as a source of energy to generate electricity or drive an industrial process. The salt can be re-used once the heat is extracted in a closed-loop system.

In some embodiments of the invention, the salt is conveyed down the well by a pneumatic conveyer system, or in other cases by using a mechanical system, such as a screw drive. Once returned to the surface, the molten salt can be used to heat graphite blocks for energy storage, or be stored and transported to remote locations to extract the heat energy.