A ladder-structural gravity-assisted-heat-pipe geothermal energy recovery system without liquid-accumulation effect, comprises a ladder-structural gravity-assisted heat pipe, a condenser, and a liquid tank. The ladder-structural gravity-assisted heat pipe comprises a return pipe, an outer pipe and an inner pipe. The return pipe is provided in a space between the outer pipe and the inner pipe and communicated with the liquid tank, and the space between the outer pipe and the inner pipe is divided to form a ladder structure. A liquid working medium flows from the liquid tank through the return pipe into each section sequentially, absorbs heat from a high-temperature rock through a wall of the outer pipe, vaporizes into a gaseous working medium, gets into the inner pipe, and rises to the condenser to condense and flows to the liquid tank to circulate. Such design greatly improves the heat transfer efficiency in geothermal energy recovery using ultra-long heat pipes.

A ladder-structural gravity-assisted-heat-pipe geothermal energy recovery system without liquid-accumulation effect, comprises a ladder-structural gravity-assisted heat pipe, a condenser, and a liquid tank. The ladder-structural gravity-assisted heat pipe comprises a return pipe, an outer pipe and an inner pipe. The return pipe is provided in a space between the outer pipe and the inner pipe and communicated with the liquid tank, and the space between the outer pipe and the inner pipe is divided to form a ladder structure. A liquid working medium flows from the liquid tank through the return pipe into each section sequentially, absorbs heat from a high-temperature rock through a wall of the outer pipe, vaporizes into a gaseous working medium, gets into the inner pipe, and rises to the condenser to condense and flows to the liquid tank to circulate. Such design greatly improves the heat transfer efficiency in geothermal energy recovery using ultra-long heat pipes.

The disclosure relates to a thermosiphon system operable to consistently maintain the permafrost and active frost layer in a frozen condition to adequately support buildings and other structures. During cooler seasons, the thermosiphon system uses a passive refrigeration cycle to efficiently maintain the frozen layers using the cold air. When the air temperature rises during the warmer months, the system transitions into an active refrigeration mode that uses a refrigeration system to minimize thawing or degradation of the permafrost and active frost layers.

A borehole is bored to a borehole target depth in a site and a geothermal heat exchanger is inserted into and then secured in the borehole at the desired depth. Once the heat exchanger has been secured in the borehole, the heat exchanger has a closed distal end and an open proximal end and has at least one fluid path between the closed distal end and the open proximal end, with installation fluid disposed in the fluid path(s). After securing the heat exchanger in the borehole and before excavation of a portion of the site immediately surrounding the borehole, the heat exchanger is temporarily sealed by installing, through the open proximal end, at least one respective internal seal in each fluid path. For each fluid path, the internal seal(s) will be disposed below a respective notional subgrade depth and excavation of the site immediately surrounding the borehole can proceed.

A refrigeration and/or heat transfer device includes a heating section and cooling section, a release member, and a one-way check valve affixed together in a continuous loop so working fluid may flow in one direction therein. The heating section absorbs heat and transfers such heat to the working fluid, thereby heating, expanding and increasing pressure upon the working fluid therein. The pressurized working fluid is released in a regulated manner from the heating section to the cooling section, thereby carrying the heat away. The released working fluid cools and transfers its heat to the surroundings within the cooling section. As released working fluid enters the cooling section, such fluid displaces already cooled working fluid, pushing such fluid through the one-way check valve back into the heating section to absorb heat. The working fluid may undergo a phase change or remain in a single phase throughout to enhance heat transfer.

Fluid classes for use in energy recovery in well and geothermal environments for power production are disclosed. The fluids fall into the classes of fluids being capable of increasing thermodynamic efficiency of electricity and/or heat generation from a closed-loop geothermal system. Numerous methods are disclosed which exploit the thermodynamics of the fluids for optimum energy recovery.

Fluid classes for use in energy recovery in well and geothermal environments for power production are disclosed. The fluids fall into the classes of fluids being capable of increasing thermodynamic efficiency of electricity and/or heat generation from a closed-loop geothermal system. Numerous methods are disclosed which exploit the thermodynamics of the fluids for optimum energy recovery.

A system for extracting geothermal heat energy: includes a geothermal well formed in surrounding crust material and extending from a well top part down to a depth where the surrounding crust material has elevated geothermal temperatures. The geothermal well includes a heat medium contained within geothermal well walls. The heat medium is heated at a well bottom part by heat extracted from the surrounding crust material, evaporating and rising to carry heat energy towards the well top part. A heat extractor, extracts heat energy from the heat medium at the well top part. At least one heat conductive path extends outwardly from the geothermal well into the crust material to conduct geothermal heat from the crust material surrounding the path towards the well bottom part.

A system for extracting geothermal heat energy: includes a geothermal well formed in surrounding crust material and extending from a well top part down to a depth where the surrounding crust material has elevated geothermal temperatures. The geothermal well includes a heat medium contained within geothermal well walls. The heat medium is heated at a well bottom part by heat extracted from the surrounding crust material, evaporating and rising to carry heat energy towards the well top part. A heat extractor, extracts heat energy from the heat medium at the well top part. At least one heat conductive path extends outwardly from the geothermal well into the crust material to conduct geothermal heat from the crust material surrounding the path towards the well bottom part.

A ladder-structural gravity-assisted-heat-pipe geothermal energy recovery system without liquid-accumulation effect, comprises a ladder-structural gravity-assisted heat pipe, a condenser, and a liquid tank. The ladder-structural gravity-assisted heat pipe comprises a return pipe, an outer pipe and an inner pipe. The return pipe is provided in a space between the outer pipe and the inner pipe and communicated with the liquid tank, and the space between the outer pipe and the inner pipe is divided to form a ladder structure. A liquid working medium flows from the liquid tank through the return pipe into each section sequentially, absorbs heat from a high-temperature rock through a wall of the outer pipe, vaporizes into a gaseous working medium, gets into the inner pipe, and rises to the condenser to condense and flows to the liquid tank to circulate. Such design greatly improves the heat transfer efficiency in geothermal energy recovery using ultra-long heat pipes.