EFFICIENT GEOTHERMAL HEAT ENERGY EXTRACTION SYSTEM

专利摘要:
Geothermal heat energy extraction system comprising: a geothermal wellbore in surrounding earth crust material extending from an upper wellbore portion to a lower lower wellbore portion at a depth where the surrounding earth crust material exhibits elevated geothermal temperatures, heating the heat medium at the lower wellbore portion by heat extracted from the surrounding earth material, evaporated and ascends, thereby transferring heat energy to the upper wellbore portion; and a heat extraction device that extracts from the upper wellbore the available heat energy carried by the heat medium; wherein at least one heat-conducting trajectory is provided in the surrounding earth crust material, the heat-conducting trajectory extending outwardly from the geothermal well into the earth's crust material to conduct geothermal heat from the earth's crust material surrounding the trajectory to the lower well bore.
公开号:BE1025635B1
申请号:E2018/5307
申请日:2018-05-09
公开日:2019-05-14
发明作者:Simon Maurice Gheysens
申请人:Sidlabz；
IPC主号:

专利说明:

Efficient qeothermal heat energy extraction system
BACKGROUND OF THE INVENTION
The present invention relates to the extraction of geothermal energy from earth material such as earth crust material, more particularly the efficient extraction of geothermal energy from earth material.
The rapidly shrinking sources of fossil fuels, combined with the polluting effects of that energy source and also of alternatives such as nuclear energy source, have led to a number of prior art attempts to convert the heat available in the earth material into alternative energy, such as electrical energy. Some prior art approaches require that multiple boreholes be drilled into the earth material, for example improved geothermal systems (enhanced geothermal systems, EGS), providing an injection well that is configured to pump a fluid such as water into the earth material, where it heats up and from which it is subsequently retrieved via a production well that is provided at some distance from the injection well. Such approaches involved many different problems, such as increased geothermal contamination due to the formation of corrosive water as it passes through the hot earth material from the injection well to the production well where the water absorbs minerals, salt and acidity; and such as increased subsidence, for example due to the breaking of earth material such as rock to form a passage from the injection well to the production well. Therefore, the general trend today is to use geothermal heat extraction systems with one partially insulated well that do not suffer from the problems of EGS systems, for example.
Many single bore heat extraction systems include a loop system within the partially insulated single borehole, such as a loop system that includes an input pipe for conveying heating fluid such as water to the uninsulated bottom of the borehole where the heating fluid heats up, and an output pipe for recovering the heated operating fluid. In such looped ones
BE2018 / 5307 single borehole geothermal energy extraction systems require a pumping mechanism, this pumping mechanism being configured to control the flow rate of the heating fluid through the loop system and also configured to ensure a controlled circulation of the heating fluid through the loop system, ie in one direction from the inlet tube to the outlet tube. These looped geothermal energy extraction systems with a single well that rely on active transport of the heating fluid by pumping the heating fluid are highly inefficient.
Therefore, passive geothermal heat extraction systems with a single well bore according to the preamble of the first claim of the present invention have been developed in the prior art, as disclosed in U.S. Patent Publication No. US 3911683. Although these passive geothermal heat extraction systems with a single well bore can show increased efficiency in certain situations compared to the looped geothermal heat extraction systems with a single well in terms of energy yield compared to energy input. , such as other single borehole heat extraction systems and unlike, for example, EGS systems, due to a shortage of available heat in the earth material, since the heat available in the relatively small area around the single borehole becomes relatively fast exhausted, for example limiting the long-term efficiency of the geothermal heat extraction system. Moreover, since the efficiency of heat transfer depends on the contact surface between the heat fluid and the heat source, for example the surrounding earth material, the efficiency of the applications with a single wellbore is rather limited compared to other systems such as EGS systems, whereby the heat fluid is dispersed in the surrounding earth material when it moves from the injection well to the production well.
However, it is known from the prior art, for example from U.S. Pat. No. US20150013981, how several short length and medium radius lateral holes can be drilled efficiently from a vertical wellbore, such as a single wellbore, from a
BE2018 / 5307 geothermal heat energy extraction system with a single closed loop borehole, to increase the efficiency of the closed loop systems. However, the prior art is only directed to non-efficient geothermal heat energy extraction systems with a single closed loop wellbore, i.e. active heat energy extraction systems.
Therefore, it is an object of the present invention to provide a single borehole passive heat extraction system with increased long-term efficiency, i.e., long service life.
Summary of the invention
In accordance with the present invention, a system is provided for extracting geothermal heat energy, the system comprising a geothermal well, such as a single geothermal well, in surrounding crust material, the geothermal well extending in a first direction, e.g. substantially along the gravitational acceleration vector, such as along the gravitational acceleration vector, from an upper wellbore portion that begins at an upper wellbore level on the surface of the earth's crust material, to a lower lower wellbore portion that is further from the surface of the earth's crust material, with the lower wellbore portion on a depth where the surrounding earth crust material exhibits geothermal temperatures higher than temperatures on the surface of the earth crust material, and ends at a lower wellbore level at the bottom of the wellbore. The geothermal well comprises a wall of the geothermal well that delimits the geothermal well relative to the surrounding earth crust material, for example by means of a small layer surrounding earth crust material or for example a reinforced wall that provides structural stability to the geothermal well. The geothermal well further comprises a heat medium configured, for example, to be heated by the surrounding earth crust material, and contained within the walls of the geothermal well, for example, not dispersed in the surrounding earth crust material as in EGS systems. The heat medium is heated at the lower wellbore portion by heat extracted from it
BE2018 / 5307 surrounding earth crust material, whereby its density decreases, for example due to evaporation, and it starts to rise, for example mainly along the first direction, and carries heat energy, for example passively without consuming energy for transport, towards the upper well section. The system further comprises a heat extraction device which extracts the available heat energy from the upper wellbore portion, which is at least partially carried by the heat medium. The system is characterized in that at least one heat-conducting path is provided in the surrounding earth crust material, the heat-conducting path extending outwards from the geothermal well into the earth's crust material to conduct geothermal heat, for example passively without using energy for transport of the earth's crust material surrounding the trajectory to the lower wellbore portion.
By providing the system with the characteristics described above, the advantage is obtained that the systems have to be installed once, after which geothermal heat energy will be extracted passively, and thus in an efficient manner, for example without having to consume energy, for example to heat transporting the surrounding earth crust material to the lower wellbore portion by natural heat conduction through at least one heat-conducting path, or, for example, to transport the heated heat medium through natural convection from the lower wellbore portion to the upper wellbore portion. More specifically, the passive, and hence efficient, extraction of geothermal heat energy will be an efficient process over a longer period of time compared to existing prior art systems, as already mentioned, due to the larger surface area surrounding the geothermal well, and which is formed by the extending heat-conducting pathways from which heat will be extracted. The extraction of the geothermal heat energy from the surrounding earth crust material of the one geothermal well depends, among other things, on the contact surface between the geothermal well and the surrounding earth crust material, for example largely determined by the surface of the wall of the geothermal well, for example completely determined through the wall of the geothermal
BE2018 / 5307 wellbore in the single-well geothermal heat extraction systems, as already mentioned. The present invention solves the efficiency problem encountered in prior art systems by providing a heat-conducting path in the earth crust material surrounding the geothermal well that extends outward from the geothermal well into the earth crust material to conducting geothermal heat from the earth's crust material surrounding the path to the lower wellbore portion, thereby increasing the contact surface between, on the one hand, the heat-conducting materials such as the heat-conducting path and the heat medium, and, on the other hand, the surrounding earth's crust material. Moreover, since the heat-conducting trajectory extends away from, ie outwards relative to, geothermal well, the conductive trajectory reaches zones of crust material outside the depletion zone, ie the zone of crust material in the vicinity of one geothermal well that after a long time of heat recovery is more geothermal heat energy stripped than zones far from the geothermal wellbore, thus reaching zones that are less affected by exhaustion, thus improving long-term efficiency, ie the long service life of the system .
According to embodiments of the present invention, the system for extracting geothermal heat energy comprises at least one single passive well. The geothermal heat energy extraction system of the present invention therefore comprises one or more single wells in which heat energy is passively extracted from the environment, i.e., without including pumps for pumping the heat medium within the single wellbore . The passive heat extraction system with a single well bore relies on passive transport of energy, on the one hand from the surrounding crust material to the heat medium, for example by heat conduction, and on the other hand from the heat medium to the heat extraction device, for example by convection of heat. Each of the single wells in the system is independent, that is, one particular, first single well does not function as a heat medium access point while another, second single well, at a remote location from the first single well,
BE2018 / 5307 functions as a starting point for heat medium, as would be the case in EGS systems, where one well functions as an injection well and another works as a production well. Providing independent wells reduces the need to pump heat medium from one well through earth crust to another well, a process that consumes energy and worsens the condition of the earth's crust, for example by breaking earth's crust material and by forming corrosive water .
It has been found that, in addition to the low energy consumption requirements, a passive single well bore according to the present invention can be easily designed with a view to obtaining a long operating time. The passive extraction of energy via the passive single well usually draws energy from the environment at a lower speed than an active single well system, creating a stable situation, ie a state of equilibrium, a situation that occurs after a lapse of a determined time after system start-up, whereby the flow that generates heat is removed, ie removed from the earth's crust material surrounding the lower wellbore portion, ie the area being depleted, by the natural conduction of geothermal heat from the earth's crust material to the heat medium which is located in the lower wellbore portion is equal to the heat flow with which the depleted zone is replenished, for example by generating heat energy or by conducting heat energy from earth crust material further away from the geothermal wellbore than the depleted zone.
According to embodiments of the present invention, the heat extraction device extracts the heat energy available at the upper wellbore portion carried by the heat medium, preferably passively carried by the heat medium.
According to embodiments of the present invention, the heat medium contained within the walls of the geothermal wellbore comprises a liquid phase and a gas phase.
According to embodiments of the present invention, the heat medium contained within the walls of the geothermal wellbore comprises a radioactive heat medium, such as radioactive waste material. It is
BE2018 / 5307 has shown that such radioactive waste material adds additional thermal energy to the heat medium, which makes it possible, for example, to reduce the depth of the geothermal well.
The presence of the two phases of the heat medium in the system makes it possible at the same time to optimize the extraction of the geothermal heat energy from the surrounding crust material, since the thermal conductivity of a liquid medium is generally higher than the thermal conductivity of a liquid medium. gaseous medium, wherein, for example, the thermal conductivity of liquid water is higher than the thermal conductivity of steam, thus improving the conduction of heat energy from the surrounding crust material to the heat medium, and on the other hand the transport of the thermal energy from the lower well section to the upper well section to be optimized, since a gaseous medium allows passive transport of heat energy through natural convection of the heat medium from the lower wellbore portion to the upper wellbore portion, for example with less flow resistance than a liquid medium heat medium .
According to embodiments of the present invention, the geothermal wellbore is filled with the liquid phase heat medium to a liquid-gas interface level at a depth where the surrounding crust material exhibits geothermal temperatures that are higher than those on the surface of the crust material.
Filling the geothermal wellbore with the liquid medium heat medium to a liquid-gas interface level at a depth where the surrounding crust material exhibits geothermal temperatures higher than those on the surface of the crust material offers the advantage that the liquid heat medium is capable of is set to extract geothermal heat energy from the surrounding crust material by changing phase, for example from liquid phase to gas phase, and allowing the extracted geothermal heat energy to be transported, for example by natural convection from the heat medium to the upper wellbore portion, where it can be used by the heat extraction device.
According to embodiments of the present invention, it extends
BE2018 / 5307 upper borehole portion extends between the upper level of the borehole and the liquid gas interface, the lower borehole portion extending between the liquid gas interface and the lower level of the borehole.
The two clearly distinct parts of the geothermal well, the lower part of the geothermal well and the upper part of the well, each have at least one function assigned thereto, for example, having the function of recovering the geothermal heat sink respectively. energy of the surrounding earth crust material and thereby heating up the liquid medium heat medium, and the function of incorporating the gas medium heat medium and thereby allowing the transport of the thermal energy, for example by natural convection of the heated gaseous heat medium along the first direction from the geothermal well to the upper level of the well. An additional function of the upper wellbore portion is thermally charging the earth's crust material surrounding the upper wellbore portion, ie supplying heat energy to the earth's crust material surrounding the upper wellbore portion, for the purpose of heating, such as raising the temperature of, the earth's crust material that surrounds the upper borehole portion such that the thermal gradient between the upper portion of the geothermal borehole and the earth's crust material that surrounds the upper borehole portion is lowered, causing the heat flow from the upper portion of the geothermal borehole to the earth's crust material after a period of time surrounding the upper wellbore portion is lowered such that a stable equilibrium situation is achieved with a minimum of heat loss to the surrounding earth crust material of the upper wellbore portion. In an alternative embodiment of the present invention, the thermal conductivity of the wall of the geothermal wellbore at the upper wellbore portion is lower than that of the surrounding crust material to reduce heat leakage to the surrounding crust material, for example by providing an insulating layer as the wall of the geothermal well at the upper part of the geothermal well. In the alternative embodiment, the thermal conductivity of the wall of the geothermal wellbore at the lower wellbore portion is higher than the thermal conductivity of the
BE2018 / 5307 surrounding earth crust material and the wall of the geothermal wellbore at the upper wellbore portion, to increase the introduction of heat energy into the geothermal wellbore through the lower portion of the geothermal wellbore.
According to embodiments of the present invention, the geothermal well comprises a heat pipe, ie it functions as a heat pipe, the heat pipe extending in a first direction from an upper portion of the heat pipe starting at an upper level of the heat pipe to a lower level lower portion of the heat pipe to terminate at a lower level of the heat pipe, wherein the heat pipe comprises a wall of the heat pipe defining the heat pipe relative to its environment and wherein the heat medium is contained within the walls of the heat pipe.
The fact that the heat pipe is provided within the geothermal well, for example with the wall of the heat pipe adjacent to the walls of the geothermal well or for example with the wall of the heat pipe at least partially integrated with the walls of the geothermal well, offers the advantage of possibility to disconnect the geothermal well and the component that delimits the heat medium, for example the pipe, for example the heat pipe. The decoupling of these two components makes it possible to optimize the characteristics of both components, it makes it possible, for example, to optimize the geothermal well in terms of structural integrity, for example robustness, or for example to apply insulation to the upper part of the geothermal well, and makes it possible to optimize the heat pipe for containing the heat medium, for example by providing a heat pipe optimized for containing a heat medium and for transporting heat energy. The provision of the heat pipe wall adjacent to the walls of the geothermal well, or at least partially integrated with the walls of the geothermal well, makes it possible to easily conduct the geothermal heat energy from the surrounding crust material to the heat medium and vice versa.
According to embodiments of the present invention, it extends
BE2018 / 5307 upper part of the heat pipe extends between the upper level of the heat pipe and the liquid-gas interface, the lower part of the heat pipe extending between the liquid-gas interface and the lower level of the heat pipe.
According to embodiments of the present invention, the heat pipe consists of a sealed, for example closed, hollow pipe, which comprises an evaporator on the lower part of the heat pipe and a capacitor on a part of the heat pipe adjacent to the upper level of the heat pipe. The walls of the heat pipe are generally made of a material that comprises at least one heat-conducting material on the lower part of the heat pipe and on the part of the heat pipe adjacent to the upper level of the heat pipe. Usually a vacuum pump is used to remove the air from the empty heat pipe before it is filled with a heat medium. The heat pipe is then partially filled with the heat medium and then sealed. The type and mass of the heat medium are selected such that the heat pipe contains both a gas phase and a liquid phase over the operating temperature range. The liquid phase will evaporate when extracting energy from the surrounding crust material and will move to the capacitor side at the upper level of the heat pipe, where it will be cooled and converted back to a liquid phase. In a standard heat pipe, the condensed liquid is returned to the evaporator at the lower part of the heat pipe by means of a wick structure provided along the side walls of the heat pipe and exerting a capillary action on the liquid phase of the heat medium. Alternatively, the heat pipe can be designed as a thermosiphon, with the condensed liquid being returned to the evaporator using gravity. A general advantage of heat pipes is that they do not contain any mechanical moving parts and therefore require little maintenance, nor do they require energy consumption for transporting the thermal energy, for example by driving a pump.
According to embodiments of the present invention, the wall of the geothermal well forms part of the wall of the heat pipe.
The system where the wall of the geothermal wellbore part
BE2018 / 5307 forms part of the wall of the heat pipe, such that the wall of the geothermal well and the wall of the heat pipe are integral, offers the advantage that the functions of delimiting the geothermal well relative to the surrounding earth crust material and the surrounding crust material containing the heat medium are integrated in the same wall.
According to embodiments of the present invention, the lower level of the heat pipe is higher than or substantially adjacent to the lower level of the wellbore. Making the lower level of the heat pipe adjacent to the lower level of the well bore optimizes the available space in the well bore.
According to embodiments of the present invention, the wall of the heat pipe extends from the lower level of the heat pipe, for example at the lower level of the wellbore, to an upper level of the heat pipe, at least the upper level of the wellbore.
Running the heat pipe from the lower level of the well bore to at least the upper level of the well bore offers the advantage that the length of the heat pipe within the geothermal well is maximized, thereby maximizing the contact surface of the heat pipe with the surrounding crust material .
According to embodiments of the present invention, the wall of the heat pipe extends above the upper level of the wellbore. In a preferred embodiment of the present invention, an upper portion of the heat pipe is provided that extends between the upper level of the heat pipe and the liquid-gas interface. In a preferred embodiment of the present invention, the heat energy carried by the heat medium and available at the upper wellbore portion is further carried to the upper portion of the heat pipe by the heat medium.
The advantage of the fact that the wall of the heat pipe extends above the upper level of the well bore is that the heat energy contained in and transported by the heat medium can be further transported from the lower well portion to the upper well portion a level that is higher than the upper level of the wellbore, which allows the heat extraction device to access more easily
BE2018 / 5307 to the heat energy, such as at a level higher than the upper level of the wellbore, i.e. the level of the surface of the earth's crust material.
According to alternative embodiments of the present invention, the wall of the heat pipe extends from a lower level of the heat pipe, e.g. at the lower level of the wellbore, to an upper level of the heat pipe below the upper level of the wellbore, e.g. half the depth of the borehole.
The provision of a heat pipe up to an upper level of the heat pipe which is substantially below the upper level of the well bore makes it possible to extract thermal energy from the earth's crust material which surrounds the lower part of the well / heat pipe and the dissipating energy extracted via the heat pipe to the earth's crust material that surrounds the upper part of the heat pipe adjacent to the upper level of the heat pipe. Under the influence of the heat released, the surrounding crust material tends to release gases into the crust material, such as methane gas, which is commonly known as mine gas. Without being bound by theory: these gases are produced by bacteria that live in water, for example mine water, at a higher speed under the influence of the elevated temperature. In addition, the heat released by the heat pipe increases the temperature of the water contained in the surrounding crust material at the upper part of the heat pipe, for example adjacent to the upper level of the heat pipe, such that the water vapor pressure increases, for example the water to boil, resulting in water vapor. The water can be naturally present water in the surrounding earth crust material, and / or water artificially added to the wellbore. Moreover, the water is not necessarily located in the surrounding crust material, but can also be located in the well above the upper part of the heat pipe, for example around it, preferably above the upper level of the heat pipe. The released gas, such as the mine gas, for example together with the water vapor, for example entrained by the water vapor, is carried passively, for example by convection, to the upper wellbore portion, preferably to the upper level of the
BE2018 / 5307 well. The heat extraction device may be configured, for example, as a group of electricity generating turbines disposed in the upper wellbore portion, for example above the upper level of the heat pipe and / or at the upper level of the wellbore, the turbines being driven by the kinetic energy from the passively rising gases, such as the mine gas, for example the methane gas, and such as the water vapor. Additionally, or alternatively, the heat extraction device may be configured to burn the released gases, such as the mine gas, to generate electrical energy. Both the kinetic energy of the rising gases and the released heat from the burning of the gases are considered as heat energy available at the upper wellbore portion, and which can be used by the heat extraction device for generating electrical energy or for directly utilizing the heat of the gases to heat a heating system.
In an embodiment of the present invention, the upper level of the heat pipe can be adjusted, for example, by providing an extendable heat pipe. The present embodiment offers the advantage that the heat pipe can be extended from an upper level of the heat pipe near the bottom of the well bore to an upper level of the heat pipe, at least at the upper level of the well bore, for example to contain gases such as methane gas in the surrounding earth crust material at any position of the wellbore. After all the gas has been recovered, for example due to the evaporation of the water in the surrounding crust material, the upper level of the heat pipe is at least the upper level of the wellbore, where the system continues to extract heat energy from the lower wellbore portion via the heat extraction device.
In one embodiment of the present invention, the heat pipe is provided in an existing wellbore, such as an abandoned mine shaft. This embodiment offers the advantage that the costs associated with drilling the well bore can be avoided. In one embodiment of the present invention, the heat pipe is provided in a new well that is dug into an existing well, such as an abandoned mine shaft. This embodiment offers the advantage that the costs associated with it
BE2018 / 5307 drilling of the wellbore can be partially avoided.
According to embodiments of the present invention, the wall of the heat pipe is made of a first heat-conducting material. According to preferred embodiments of the present invention, the first heat-conducting material has a heat conductivity of more than 30 W / (m.K), preferably more than 100 W / (m.K).
Providing the wall of the heat pipe with a heat-conducting material allows the geothermal heat energy to be transferred from the surrounding earth crust material to the heat medium and vice versa. The thermal conductivity of at least 30W / (m.K) appears to be suitable for many situations. The wall of the heat pipe preferably has a thermal conductivity of at least 100 W / (m.K), which appears to be most suitable for many situations.
According to embodiments of the present invention, the lower wellbore portion is a heat recovery component. In a preferred embodiment of the present invention, the heat recovery component is configured to exchange heat between the surrounding earth crust material around the heat recovery component and the heat medium contained within the heat recovery component. In order for the heat recovery component to exchange heat between the surrounding crust material of the heat recovery component and the heat medium, the borehole wall functions as a heat exchanger, providing an increased contact area to increase the heat inflow to the heat medium. In preferred embodiments of the present invention, both the borehole wall and the heat pipe wall, or the borehole wall as part of the heat pipe wall, function as a heat exchanger by providing an enlarged contact surface. to increase the heat inflow to the heat medium.
According to embodiments of the present invention, the geothermal temperatures of the earth's crust material surrounding the lower wellbore portion are at least the boiling temperature of the heat medium, such as the liquid heat medium, at the pressure present in the lower portion of the geothermal wellbore or heat pipe. More specifically
BE2018 / 5307, the earth's crust material surrounding the lower wellbore portion, adjacent the wellbore wall of the lower wellbore portion, is within a range of temperatures at least equal to the boiling temperature of the heat medium, such as the liquid heat medium, located within the walls of the bottom of the borehole, such as the wall of the boreholes or the walls of the heat pipe, at the time of the start-up of the geothermal borehole, ie the start-up whereby the geothermal borehole is filled with liquid heat medium. According to a preferred embodiment of the present invention, the earth's crust material surrounding the lower wellbore portion, adjacent to the borehole wall of the lower wellbore portion, is within a range of temperatures at least equal to the boiling temperature of the heat medium, such as the liquid heat medium, which is located inside the walls of the bottom of the borehole, such as the wall of the boreholes or the walls of the heat pipe, after establishing a stable situation, that is to say, in a state of equilibrium, a situation occurring occurs after a certain period of time after system start-up, whereby the flow that generates heat is removed, ie, from the earth's crust material surrounding the lower wellbore portion, that is, the zone being depleted, by the natural conduction of the geothermal heat from the earth's crust material to the heat medium located in the lower wellbore This part is equal to the heat flow with which the depleted zone is replenished, for example by generating heat energy or by conducting heat energy from earth crust material further away from the geothermal wellbore than the depleted zone. The provision of the at least one heat-conducting path has been found to be crucial for achieving such a balance.
According to embodiments of the present invention, the at least one heat-conducting path extends outwardly from the wall of the geothermal wellbore into the earth's crust material surrounding the wall of the geothermal wellbore.
That the system has at least one heat-conducting path extending outward from the wall of the geothermal well into the earth's crust material surrounding the wall of the geothermal well
BE2018 / 5307 has the advantage that the geothermal heat can be extracted from earth's crust material at a certain distance from the geothermal well. The embodiment is particularly advantageous in situations where the wall of the wellbore from which the at least one heat-conducting path branches off contains the heat medium in liquid phase, i.e. adjacent to the heat medium,
i.e., is in direct contact with the heat medium in liquid phase, and thus in situations where no heat pipe is provided in the geothermal well or in situations where the wall of the geothermal well forms part of the wall of the heat pipe.
According to embodiments of the present invention, the at least one heat-conducting path extends outwardly from the wall of the heat pipe into the earth's crust material.
The fact that the system has at least one heat-conducting path extending outward from the wall of the heat pipe into the earth's crust material surrounding the wall of the geothermal borehole offers the advantage that the geothermal heat from earth's crust material is at a certain distance from the geothermal well can be extracted. The embodiment is particularly advantageous in situations where the wall of the geothermal well is not part of the wall of the heat pipe, for example in situations where the wall of the geothermal well is optimized in terms of structural integrity but does not have good thermally conductive properties since in those situations the at least one conductive path can be arranged to extend outwardly from the wall of the heat pipe through the wall of the geothermal well and into the earth's crust material surrounding the wall of the geothermal well.
According to embodiments of the present invention, the at least one heat-conducting path extends outwardly from the lower portion of the geothermal wellbore into the earth's crust material surrounding the lower portion of the geothermal wellbore.
That the system has at least one heat-conducting path extending outward from the lower portion of the geothermal well into the earth's crust material surrounding the lower portion of the geothermal well offers the advantage that the geothermal
BE2018 / 5307 heat from earth's crust material at a certain distance from the geothermal well can be recovered and directed to the liquid heat medium located within the lower portion of the geothermal well.
According to embodiments of the present invention, the at least one heat-conducting pathway is a naturally occurring layer in the surrounding earth crust material, the naturally occurring layer having a thermal conductivity of more than 30 W / (m.K).
That the system has at least one heat-conducting trajectory that is a naturally occurring layer in the surrounding earth crust material offers the advantage that the conductive trajectory can reach far outward from the geothermal wellbore and thus recover geothermal energy from far from the geothermal borehole earth crust material. Naturally occurring layers with a thermal conductivity of more than 30 W / (mK) offer the advantage that they conduct the geothermal heat energy efficiently in comparison with the transport that takes place through the earth's crust material surrounding the geothermal wellbore with lower values of thermal conductivity.
According to embodiments of the present invention, the at least one heat-conducting path is a path that is made, for example, drilled, into the surrounding crust material and filled with a second heat-conducting material.
The system in which the at least one heat-conducting path is a path that is made, for example, drilled, into the surrounding earth crust material and filled with a second heat-conducting material, offers the advantage that it is not dependent on the location where the geothermal well is placed, since the geothermal well should not be placed at, for example, a location where the Earth's crust material comprises naturally occurring layers of material with a thermal conductivity of more than 30 W / (mK). Moreover, the heat-conducting pathways can be provided in any shape and dimensions. A preferred embodiment of the present invention is a system in which the at least one heat-conducting path is a drilled tap in the surrounding earth crust material, which extends over, for example, a certain
BE2018 / 5307 length, for example 10 meter, extends outwards in one direction relative to the geothermal well, for example at an angle with respect to the surface of the surface of the earth's crust material, for example in the surface of the surface of the earth's crust material, to any position in the lower part of the geothermal well. An additional embodiment of the present invention is a system in which the at least one heat-conducting path is a drilled disc in the surrounding crust material, ie a disc centered around the geothermal well with a radius of 10 meters, for example at an angle to the surface of the surface of the earth's crust material, for example in the surface of the surface of the earth's crust material, at any position in the lower part of the geothermal well. An additional embodiment of the present invention is a system in which the heat-conducting path is two drilled taps in the surrounding earth's crust material which, for example, extend over a certain length, for example 10 meters, in two different directions, for example in the same plane at an angle of 180 °, extend outwards with respect to the geothermal well.
According to embodiments of the present invention, the at least one heat-conducting path is a network of veins created in the surrounding earth's crust material, for example by fracking, and in the case of fracking, for example, by applying high-pressure fluid to the geothermal well. Advantageously, the network of cores that forms the at least one heat-conducting path is created by applying a liquid second heat-conducting material, for example under pressure, for example for fracking the surrounding earth crust material.
The at least one heat-conducting path, which is formed, for example, by the fracturing of the surrounding earth's crust material, offers the advantage that a huge network of veins is created in the surrounding earth's crust material, wherein the network of veins has a high surface-to-volume ratio compared to a heat-conducting path created as a drilled cylinder with the same volume. Such a high surface-to-volume ratio increases the efficiency with which thermal energy can be recovered by the heat-conducting path.
BE2018 / 5307
According to embodiments of the present invention, the at least one heat-conducting pathway is, for example, a naturally occurring network of veins in the surrounding earth's crust material, which is filled with the second heat-conducting material.
That the at least one heat-conducting pathway is provided as a naturally occurring network of veins in the surrounding earth's crust material, which is filled with the second heat-conducting material, offers the advantage that no additional time and energy have to be invested to create the network of veins.
According to embodiments of the present invention, the at least one heat-conducting path, for example a network of conductors or a drilled tap that is subsequently filled with a second heat-conducting material, is structurally stabilized by the second heat-conducting material. The second heat-conducting material fills the hole created, for example, as a drilled tap or as a network of cores formed by fracking, thereby reducing the risk of the hole collapsing. Filling the gaps greatly reduces the risk of subsidence.
According to embodiments of the present invention, the second heat-conducting material contained in the heat-conducting tap is a liquid.
According to embodiments of the present invention, the second heat-conducting material contained in the heat-conducting tap is a solid.
According to embodiments of the present invention, the heat transfer from the crust of the earth surrounding the heat-conducting path to the heat medium located within the geothermal well is carried out essentially, for example, exclusively by heat conduction, for example without any heat convection taking place in the heat-conducting path, ie the second heat-conducting material that is in the heat-conducting path does not undergo mass transport.
According to embodiments of the present invention, the second heat-conducting material has a thermal conductivity of at least 30W / (m.K). According to embodiments of the present invention
BE2018 / 5307 the second heat-conducting material comprises at least one of carbon, beryllium, sodium, magnesium, aluminum, silicon, potassium, calcium, iron, chromium, nickel, cobalt, copper, zinc, molybdenum, ruthenium, rhodium, silver, cadmium, tungsten, iridium and gold. The second heat-conducting material preferably occurs naturally in the surrounding crust material, and is, for example, a naturally occurring ore layer in the surrounding crust material.
Embodiments in which the second heat-conducting material is one of the above offer the advantage that good thermal conductivity is obtained. Preferably one of sodium, potassium and calcium is used, since these materials have a relatively low melting point, for example a melting point below 200 ° C, such as around 100 ° C, whereby they melt at the geothermal temperatures at the bottom of the wellbore, which offers the advantage that the molten materials easily penetrate into the created, for example, drilled, path to form the heat-conducting path.
According to embodiments of the present invention, the at least one heat-conducting path, for example, the conductors, is created by applying the second liquid-conducting liquid-phase material in the lower wellbore portion, for example, after drilling and / or fracking the path in the surrounding environment earth crust material.
The provision of the second liquid-conducting liquid-phase material in the lower wellbore portion offers the advantage that the efficiency of, for example, the fracking process is increased, since a liquid second heat-conducting material more easily induces and penetrates veins in the surrounding crust material than solid second heat-conducting material. Moreover, the provision of liquid second heat-conducting material in the lower wellbore portion makes it possible to more easily fill the at least one created, for example, drilled, heat-conducting path compared to filling with second solid-state heat-conducting material, because during the filling of the heat-conducting path the liquid second heat-conducting material easily flows into the at least one created, e.g., drilled path, and thus correctly fills the created, e.g., drilled path.
BE2018 / 5307
According to embodiments of the present invention, the heat extraction device during its operation uses thermal energy available at the upper portion of the heat pipe, which is entrained, for example, passively, by the heat medium.
The system whereby the heat extraction device during its operation uses thermal energy available at the upper part of the heat pipe, carried along, for example passively, through the heat medium, offers the advantage that the heat extraction device is above the upper level of the geothermal well, and thus above the level of the surface of the earth's crust material. This makes it possible to use above-ground installations that are easier to implement, for example because a heat extraction device for generating geothermal energy requires a cold side to condense the gaseous heat medium, which is difficult to implement underground is, for example, due to the higher underground geothermal temperatures. On the cold side, for example, a chimney or cooling tower can be provided, which can also gain additional energy, for example electrical energy, by capturing the energy of the naturally occurring air stream of heated air, for example by providing a wind turbine in the range of the heated air flow. Such energy capture improves the overall efficiency of energy generation by converting heat to electrical energy even more. As the heat is withdrawn from the gaseous heat medium at the heat extraction device, the heat medium loses thermal energy, thereby decreasing its temperature and releasing, for example, latent energy by changing phase, e.g. from gas to liquid. The phase change, for example, causes the density of the heat medium to decrease, whereby the heat medium tends to fall back to the lower wellbore portion under the influence of gravity. To minimize entrainment of the heat medium falling back to the lower wellbore portion, or to reduce the need for a wick structure in the heat pipe, or in embodiments where the gaseous heat medium can escape from the heat pipe or geothermal well, an embodiment of the present invention provides invention in addition to
BE2018 / 5307 heat medium in the heat pipe or geothermal well, for example by replenishing the heat pipe or geothermal well with liquid heat medium. In addition, a wick structure can be provided along the side walls of the heat pipe to promote the return of heat medium to the lower wellbore portion. In such an embodiment the heat medium will rise centrally in the heat pipe and will fall back via the side walls of the heat pipe, for example by means of capillary action by the wick and / or by means of gravity.
According to embodiments of the present invention, the heat extraction device comprises a conversion device for converting the heat energy into electrical energy. To this end, the heat extraction device can for instance comprise a turbine, a thermionic generator or other known electric generators which can convert the available thermal energy into electrical energy. In the embodiment, the heat extraction device comprises a usable heat circuit comprising a second heat medium, which is, for example, different from the heat medium located in the geothermal well, which is the first heat medium, for example in a gas phase, such as steam. According to an embodiment of the present invention, the second gas-phase heat medium drives a turbine, such as a steam turbine, for example for generating electricity. According to embodiments of the present invention, the heat extraction device comprises a chimney, for example provided with the heated usable heat circuit at the bottom of the chimney, configured to extract thermal energy from the heated usable heat circuit, for example by providing windmills in the chimney that electrically generate energy through the natural air flow created in the chimney because the heated usable heat circuit heats up air at the bottom of the chimney. According to embodiments of the present invention, thermal energy is converted to electrical energy by successively extracting thermal energy from the heated useful heat circuit through the steam turbine and through the chimney.
That the system comprises a heat extraction device which comprises a usable heat circuit with a second heat medium in a gas phase,
BE2018 / 5307 in which the second gas-fired heat medium drives a turbine, for example for generating electricity, offers the advantage that environmentally friendly electrical power is generated. The system in which the thermal energy is successively converted into electrical energy through the steam turbine and through the chimney offers the advantage that the thermal energy present in the heated usable heat circuit is optimally extracted, that is, a larger percentage of the heat present in the usable heat circuit is used, thereby improving the ratio of heat to electricity conversion.
According to embodiments of the present invention, the heat extraction device comprises a usable heat circuit comprising a second heat medium, such as water or steam, wherein the usable heat circuit located in the heat extraction device is configured to heat up a heating system. More specifically, the usable heat circuit located in the heat extraction device is configured to directly use the heat from the heated second heat medium located within the usable heat circuit, e.g. configured to directly heat, for example, a surface, e.g. covered road or a floor of a house, or configured, for example, to promote an endothermic chemical process such as cleaning carbon dioxide absorption devices after the absorption of carbon dioxide in the carbon dioxide absorption device. To this end, the usable heat circuit is arranged adjacent to the surface to be heated. According to embodiments of the present invention, the heat extraction device is configured to successively convert thermal energy present in the heated useful heat circuit to electrical energy and to directly use the thermal energy present in the heated useful heat circuit.
That the system comprises a heat extractor comprising a usable heat circuit with a second heat medium, the usable heat circuit located in the heat extractor being configured to directly use the heat of the heated second heat medium located within it
BE2018 / 5307 usable heat circuit, offers the advantage that an environmentally friendly heating system is provided. The heat extraction device with a carbon dioxide absorption device that uses the heat from the heated usable heat circuit offers the advantage that carbon dioxide is absorbed from the atmosphere in an environmentally friendly manner, ie without the heat required for endothermic cleaning of the carbon dioxide absorption - equipment must be generated with the help of environmental pollutants such as the traditional burning of fossil fuels. That the system is configured to successively convert thermal energy present in the heated usable heat circuit to electrical energy and to directly use the thermal energy present in the warmed usable heat circuit offers the advantage that the thermal energy present in the heated Heated usable heat circuit is optimally extracted, ie a larger percentage of the heat present in the usable heat circuit is used.
According to embodiments of the present invention, the heat extraction device comprises a heat exchanger for indirectly heating the usable heat circuit with heat available in the upper wellbore portion. According to embodiments of the present invention, the heat extraction device comprises a heat exchanger for indirectly heating the usable heat circuit with heat available in the upper portion of the heat pipe. For example, the heat exchanger would be an entanglement of, on the one hand, one of the upper portion of the heat pipe and the upper wellbore portion, and, on the other hand, the usable heat circuit. For example, in embodiments where the second heat medium located within the usable heat circuit and heated via a heat exchanger according to the present embodiment is in a gas phase, the transformation of the second heat medium can be promoted by providing a flash turbine is located in the heat extraction device, wherein the flash turbine uses the heated second heat medium, such as heated water, to generate a gas phase of the second heat medium, such as steam, to drive the turbine, for example for generating electricity. In
BE2018 / 5307 alternative embodiments of the present invention, the usable heat circuit is connected to one of the geothermal well and the heat pipe, such that the second heat medium is the first heat medium.
The system wherein the heat extraction device comprises a heat exchanger for indirectly heating the usable heat circuit with heat available in one of the upper wellbore portion and the upper portion of the heat pipe provides the advantage of disconnecting the usable heat circuit that is located in the heat exchanger and one of the upper part of the heat pipe and the upper well bore. The decoupling of the two components makes it possible to isolate one of the geothermal well and the heat pipe from the usable heat circuit, whereby the first heat medium remains contained within the geothermal well and the heat pipe, respectively. This embodiment is particularly advantageous when the first heat medium is a hazardous medium, such as a toxic medium or a radioactive medium, for which insulation with the second heat medium from the usable heat circuit is designated.
According to embodiments of the present invention, at least two heat pipes are provided in the geothermal well. More specifically, at least a first heat pipe is provided which comprises the heat medium of the first heat pipe, the lower level of the first heat pipe being adjacent to the lower level of the geothermal well, and a second heat pipe is provided comprising heat medium, the heat medium of the second heat pipe, wherein the upper level of the second heat pipe is located at least at the upper level of the geothermal well, such that the top of the first heat pipe, the upper level of the first heat pipe, and the bottom of the second heat pipe, lower level of the second heat pipe are configured to indirectly exchange heat, for example, because the lower level of the second heat pipe is adjacent to the upper level of the first heat pipe or because the upper part of the first heat pipe is entangled with the lower part of the second heat pipe. In an embodiment of the present invention, the heat medium of the first heat pipe located in the first heat pipe is a radioactive heat medium, such as radioactive
BE2018 / 5307 waste material, which supplies additional thermal energy to the heat medium of the second heat pipe located in the second heat pipe, which makes it possible, for example, to keep the depth more limited than without the radioactive heat medium. In this embodiment, the heat pipe wall material of the first wall of the heat pipe and the second wall of the heat pipe are different. The heat pipe wall material of the second wall of the heat pipe is the first heat-conducting material, and the heat pipe wall material of the first wall of the heat pipe, which borders the radioactive heat medium from the heat pipe, is made of a material that is resistant to radioactive radiation. The material that is resistant to radioactive radiation is preferably resistant to typical temperatures of radioactive heat medium material, which are dependent on the type of radioactive waste material used.
The system in which at least two heat pipes are provided in the geothermal well offers the advantage of disconnecting the two heat pipes, which makes it possible to isolate the two heat pipes, whereby the first heat medium remains enclosed in the first heat pipe. This embodiment is particularly advantageous when the first heat medium is a hazardous medium, such as a toxic medium or a radioactive medium, for which insulation with heat medium from the second heat pipe, for example water, is indicated.
According to embodiments of the present invention, the geothermal well has a well depth between the upper level of the well and the lower level of the well that is determined by the height of crust material temperatures as a function of depth at the location of the geothermal well. Since in general the temperature in the earth's crust rises in function of increasing depth, the following applies: the deeper the geothermal well, the better. More specifically, the depth of the geothermal well is adjusted such that at the time of starting up the geothermal well, the temperature range at the bottom of the geothermal well is at least the boiling temperature of the first heat medium. In a preferred embodiment of the present invention, the depth of the geothermal well is adjusted such that in equilibrium the temperature range at the bottom of
BE2018 / 5307 the geothermal well is at least the boiling temperature of the first heat medium at the pressure in the geothermal well. According to embodiments of the present invention, the depth of the well bore is between 1 and 6 kilometers, for example at least 3 kilometers. At such depths, such as, for example, at a depth of 6 km, temperatures of, for example, 200 ° C can be achieved, which results in conditions of improved energy conversion.
The fact that the system comprises a geothermal well where the depth of the geothermal well is adjusted such that in equilibrium the temperature range at the bottom of the geothermal well is at least the boiling temperature of the first heat medium provides the advantage that the first heat medium is enabled for boiling, thereby accelerating the formation of first heat medium in gas phase, which is optimal for transporting the thermal energy to one of the upper wellbore portion and the upper portion of the heat pipe.
According to embodiments of the present invention, the wall of the geothermal wellbore, preferably the wall of the wellbore of the lower wellbore portion, preferably the lower portion of the heat pipe, preferably including the heat-conducting trajectories, has an area determined on based on at least the required heat transfer capacity. More specifically, increasing the area of the lower part of the geothermal well usually leads to an increase in the rate at which heat can be extracted and transferred to the first heat medium, to a rate at which one of the limits on the replenishment rate is reached of the earth's crust material surrounding the lower wellbore portion, ie by generating heat energy and by conducting heat energy from earth's crust material further away from the geothermal wellbore than the depleted zone in the vicinity of the geothermal wellbore, and with regard to the heat transfer capacity of the first heat medium, ie the rate at which the heat medium can transport the recovered geothermal heat to one of the upper wellbore portion and the upper portion of the heat pipe. According to preferred embodiments of the present invention, a cylindrical geothermal becomes
BE2018 / 5307 borehole with a diameter of at least 10 cm. Determining the dimensions of the geothermal well, the heat pipe, the heat-conducting path, etc. is highly dependent on at least the type of surrounding crust material, the temperature at a given depth in the surrounding crust material, the desired amount of energy that is transported to the surface , etc.
The present invention also relates to a method for producing the heat extraction system according to any of the preceding embodiments of the present invention, the method comprising a set of steps. A first step involves making, such as drilling, the geothermal well in the surrounding crust material from the upper level of the well at the surface of the crust material to a lower lower level of the well at a depth where the surrounding earth crust material exhibits geothermal temperatures higher than those on the surface of the Earth's crust material. An additional step comprises at least partially filling the geothermal well with the heat medium such that the heat medium is kept within the walls of the geothermal well by the walls of the geothermal well. An additional step involves installing the heat extraction device at the upper level of the wellbore.
The method for producing the heat extraction system offers the advantage that a simple and fast way is provided for implementing an energy-efficient geothermal well, for example, by implementing the geothermal well in an area where the crust material has natural layers of heat-conducting material with a thermal conductivity of more than 30 W / (mK).
According to embodiments of the present invention, the method for producing the heat extraction system further comprises the steps of making, such as drilling, at least one path extending from the geothermal well into the surrounding earth crust material, and filling the at least one path with the second heat-conducting material. The method allows the production of an energy-efficient heat extraction system without the need to
BE2018 / 5307 for example to make excessively deep and wide wells, which is expensive and time-consuming.
The method for producing the heat extraction system according to the present embodiment offers the advantage that a simple and fast way is provided for implementing an energy efficient geothermal well, for example by implementing the geothermal well in an area where the crust material does not have natural layers of thermally conductive material with a thermal conductivity of more than 30 W / (mK). The method allows the production of an energy-efficient heat extraction system without the necessity of, for example, making excessively deep and wide wells, which is expensive and time-consuming.
According to embodiments of the present invention, the method for producing the heat extraction system further comprises the step of introducing the heat pipe into the geothermal well.
According to embodiments of the present invention, the method for producing the heat extraction system further comprises the step of introducing the heat pipe into the geothermal well from a lower level of the heat pipe at the lower level of the well to an upper level of the heat pipe, at least at the upper level of the well bore. According to an embodiment of the present invention, the at least one path extends through the wall of the borehole and is connected to the wall of the heat pipe, for example, by welding the filled path to the wall of the heat pipe.
The method for producing the heat extraction system according to the present embodiment offers the advantage of optimally producing a geothermal heat extraction system by concentrating on creating a structurally stable geothermal well, without the need to to worry about other aspects, such as the permeability of the borehole wall with respect to the heat medium located within the geothermal borehole wall. In addition, the present embodiment makes it possible to recover existing wells, such as wells previously drilled, for example for oil collection, or as naturally occurring ones
BE2018 / 5307 wells, for example by only integrating a heat pipe into the existing well in the surrounding earth crust material, or by only drilling at least one path and filling the at least one path before the heat pipe is introduced into the geothermal well, it is an economically interesting production process.
The present invention also relates to a use of the heat extraction system according to any of the preceding embodiments concerning the heat extraction system. More specifically, the present invention also relates to the use of the heat extraction system to extract heat from the surrounding earth crust material of the geothermal well.
The use of the heat extraction system enables the user to obtain environmentally friendly energy in an efficient and therefore cost-effective way.
According to embodiments of the present invention, the use of the heat extraction system comprises the use of the heat extraction device which uses the heated heat medium for generating electricity.
The use of the heated medium in the heat extraction system of the heat extraction system for generating electricity enables the user to obtain environmentally friendly electrical energy in an efficient and therefore cost-effective manner.
According to embodiments of the present invention, the use of the heat extraction system includes the use of the heat extraction device that utilizes the heat exchanger to indirectly heat the usable heat circuit with heat available in the upper wellbore portion. For this purpose, for example, a heat exchanger with concentric tube can be used, wherein the heat exchanger of the heat extraction device provides an outer tube which surrounds the heat pipe or the upper part of the geothermal well, such that heat is transferred between the outer tube, for example the usable heat circuit that is located in the outer tube, and the heat pipe or the upper part of the geothermal well.
The indirect use of the heated heat medium states
BE2018 / 5307 allows the user to be isolated from the heated heat medium, which may, for example, be toxic or radioactive.
Detailed description
Other details and advantages of the method according to the invention will be apparent from the enclosed figures and the preferred description of embodiments of the invention.
Figure 1 shows a cross-sectional side view of the geothermal heat extraction system.
Figure 1 shows an embodiment of a geothermal heat extraction system 1 comprising a heat extraction device 11 and a geothermal well 2, said geothermal well being in the earth's crust material 3.
The earth's crust material 3 forms part of the earth above the mantle of the earth and can consist of many different types of soil and rock material. The earth's crust material extends in the direction opposite to the gravitational acceleration vector to a surface of the earth's crust material 14 where the geothermal well 2 reaches an upper level of the geothermal well 5, and where the heat extraction device 11 is located. The geothermal wellbore 2 extends in a first direction along the gravitational acceleration vector, from an upper wellbore portion 4 that starts at an upper wellbore level 5 on the surface of the earth's crust material 14 to a lower lower wellbore portion 6 that is further away from the surface of the earth's crust material 14, wherein the lower wellbore portion 6 is at a depth where the surrounding earth's crust material 3 exhibits geothermal temperatures higher than temperatures on the surface of the earth's crust material 14 and ends at a lower wellbore level 7 at the bottom of the wellbore 2. The geothermal borehole comprises a wall of geothermal borehole 8 that delimits the geothermal borehole with respect to the surrounding crust material 3 by means of a thermally conductive reinforced wall providing structural stability to the geothermal borehole and acts as a heat pipe, the walls of the heat pipe p the walls
BE2018 / 5307 of the geothermal wellbore 8, and an upper part of the heat pipe and a lower part of the heat pipe are respectively the upper part of the geothermal wellbore 4 and the lower part of the geothermal wellbore 6. Preferably, the thermal conductivity of the upper part 4 is lower than the surrounding earth crust material to reduce the leakage of heat to the surrounding earth crust material, for example by providing an insulating layer on the upper part 4 of the geothermal well (not shown in the figure). ). Preferably, the thermal conductivity of the lower portion of the geothermal well 6 is higher than the surrounding earth crust material to increase the introduction of heat energy into the geothermal well. The geothermal well 2 further comprises a heat medium such as water 9,10 configured to be heated by the surrounding earth crust material 3 contained within the walls of the geothermal well 8. The heat medium 9,10 contained within the walls of the geothermal wellbore 8 comprises a liquid phase 9 and a gas phase 10, the geothermal wellbore 2 being filled with the heat medium in liquid phase 9 to a liquid-gas interface level 13 at a depth where the surrounding earth crust material 3 exhibits geothermal temperatures higher than temperatures on the surface of the earth's crust material 14, and wherein the upper wellbore portion 4 extends between the upper level of the wellbore 5 and the liquid gas interface 13, and wherein the lower wellbore portion 6 extends between the liquid gas interface 13 and the lower level of the borehole 7. The heat medium in liquid phase 9 is heated at the lower borehole section e 6 by heat extracted from the surrounding earth's crust material 3, whereby it evaporates, and consequently changes phase and absorbs energy, and then rises, mainly along the first direction, and carries heat energy, for example passively, without transporting energy for transport to the upper level of the borehole 5 in the upper borehole section 4. More specifically, heat energy is conducted from the earth's crust material 3 to the liquid heat medium 9 in the lower borehole section 6, via the heat-conducting wall of the heat pipe and the geothermal borehole 8. The conduction occurs due to the temperature difference between the liquid heat medium 9 in the lower one
BE2018 / 5307 borehole portion 6 and the surrounding earth crust material 3, wherein this earth crust material 3 is preferably at a temperature at least equal to the boiling temperature of the liquid heat medium 9 in equilibrium state, ie the state of thermal equilibrium that is established after a time span of heat extraction after the start-up of the geothermal well by filling the well 2 with the heat medium 9. The walls of the heat pipe and the geothermal well 8 on the lower part of the geothermal well 6 function as a hob for the liquid heat medium 9 which is brought to a boil, whereby the heat medium in gas phase 10 is formed. More specifically, as heat is added to the equilibrium liquid heat medium 9, the amount of gas phase 10 will increase relative to the amount of liquid phase 9. The liquid heat medium 9 will go through different stages as it rises along the first direction of the geothermal well 2 First, convection transport from the liquid heat medium 9 to the upper wellbore portion will take place, followed by a flow with bubble formation where bubbles are formed and rise due to their lower density and higher buoyancy, a stage called supercooled cooking, followed by a stage of saturated seed boiling, in which bubbles converge in a slug flow, followed by an annular flow in that the gaseous heat medium 10 presses the liquid heat medium 9 to the walls of the geothermal wellbore 8, followed by an annular flow with entrainment where the liquid heat medium 9 enters the wall of the geothermal wellbore 8 is reheated to the gas phase 10 heat medium, and is followed by a droplet flow where the walls of the geothermal wellbore 8 cool due to heat losses from the wall of the geothermal wellbore 8 in higher zones, resulting in the formation of droplets on the walls, these drops moving by gravity to the lower part of the geothermal well 6. The side walls of the heat pipe 8 are preferably provided with a wick which is provided along the side walls of the heat pipe and which allows the return of the condensed heat medium 10 to the lower wellbore section 6.
The system further comprises the heat extraction device 11 connected to it
BE2018 / 5307 upper wellbore section 4 extracts the available heat energy carried by the gaseous heat medium 10, for example by providing a heat extraction device 11 at the upper level of the wellbore 5 to extract the energy to a second usable heat circuit . The heat can, for example, be used to generate electricity.
The system is characterized in that at least one heat-conducting path 12 is provided in the surrounding earth crust material 3, the heat-conducting path extending outwards from the wall of the heat pipe and the geothermal wellbore 8 to the earth's crust material 3 to provide geothermal heat, for example passive without consuming energy for transport, to guide the earth crust material 3 surrounding the path 12 to the lower well bore section 6. The heat conducting path 12 is connected to, for example, welded to the wall of the heat pipe and the geothermal borehole 8 to maximize the heat-conducting path 12 and the wall of the heat pipe and the geothermal well 8. For the sake of clarity, the operation of a heat pipe as used in the present invention will be explained. A typical heat pipe consists of a sealed pipe 8 comprising an evaporator on the lower part of the heat pipe 6 and a capacitor on a part of the heat pipe adjacent to the upper level of the heat pipe 5. The walls of the heat pipe 8 are usually made of a material comprising at least one heat-conducting material on the lower part of the heat pipe 6 and on the part of the heat pipe adjacent to the upper level of the heat pipe 5. Usually a vacuum pump is used to remove the air from the empty heat pipe before being filled with a heat medium 9.10. The heat pipe is then partially filled with the heat medium 9.10 and then sealed. The type and mass of the heat medium 9, 10 are selected such that the heat pipe contains both a gas phase 10 and a liquid phase 9 over the operating temperature range. The saturated liquid phase 9 will evaporate when extracting energy from the surrounding earth crust material 3 and will move to the capacitor side at the upper level of the heat pipe 5, where it will be cooled and converted again into a saturated liquid phase 9. In a standard heat pipe
BE2018 / 5307, the condensed liquid 9 is returned to the evaporator on the lower part of the heat pipe 9 by means of a wick structure provided along the side walls of the heat pipe and exerting a capillary action on the liquid phase 10 of the heat medium. Alternatively, the heat pipe can be designed as a thermosiphon, with the condensed liquid 9 being returned to the evaporator using gravity. A general advantage of heat pipes is that they do not contain any mechanical moving parts and therefore require little maintenance, and they also do not require energy consumption for transporting the thermal energy, for example by driving a pump.

权利要求:
Claims (34)
[1]
Conclusions
1. Geothermal heat energy extraction system (1) comprising:
• a passive geothermal wellbore (2) in surrounding crust material (3), wherein the passive geothermal wellbore (2) extends in a first direction from an upper wellbore portion (4) that starts at an upper wellbore level (5) on the surface of the earth crust material (14) up to a lower lower well section (6) that is further from the surface of the earth crust material (14) and ends at a lower well level, the lower well section (6) being at a depth where the surrounding earth crust material (3) exhibits geothermal temperatures higher than temperatures on the surface of the earth crust material (14), wherein the geothermal well bore (2) comprises a wall of the geothermal well bore (8) defining the geothermal well bore (2) from the surrounding earth crust material (3), • a heat pipe located in the passive geothermal well (2), the heat pipe extending in a first direction from an upper part of the heat pipe starting from an upper level of the heat pipe to a lower lower part of the heat pipe to end at a lower level of the heat pipe, the heat pipe comprising a wall of the heat pipe that the heat pipe defines with respect to its environment and wherein the heat pipe further comprises a heat medium (9, 10) contained within the walls of the heat pipe,
BE2018 / 5307
BE2018 / 5307 wherein the heat medium (9) is heated at the lower portion of the heat pipe by heat extracted from the surrounding earth crust material (3), its density decreasing and rising, and passively carrying heat energy to the upper level of the heat pipe, wherein the heat pipe is provided with a wick along the side walls of the heat pipe, and wherein the wall of the heat pipe is made of a first heat-conducting material, • a heat extraction device (11), which is connected to the upper wellbore section (4) extracts the available heat energy, wherein at least one heat-conducting path (12) is provided in the surrounding earth crust material (3), the heat-conducting path (12) extending outwards from the geothermal well (2) to the earth's crust material (3) to conduct geothermal heat from the earth's crust material (3) that surrounds the pathway (12) to the lower part of the geothermal orput (6).
[2]
The geothermal heat extraction system (1) according to the preceding claim, wherein the at least one heat-conducting path is filled with a second heat-conducting material, and wherein the second heat-conducting material contained in the heat-conducting path is a solid .
[3]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the wall of the geothermal wellbore (8) forms part of the wall of the heat pipe.
[4]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein
BE2018 / 5307
BE2018 / 5307 the at least one heat-conducting path (12) extends outwardly from the wall of the heat pipe into the earth's crust material (3) that surrounds the wall of the geothermal well (8).
[5]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the heat medium (9, 10) contained within the walls of the heat pipe (8) is a liquid phase (9) and comprises a gas phase (10).
[6]
The geothermal heat extraction system (1) according to the preceding claim, wherein the heat medium (9, 10) after being heated from the liquid phase (9) evaporates to the gas phase (10).
[7]
The geothermal heat extraction system (1) according to any of the preceding claims 5-6, wherein the heat pipe (2) is filled with the liquid phase heat medium (9) to a liquid-gas interface level (13) at a depth where the surrounding crust material (3) exhibits geothermal temperatures higher than temperatures on the surface of the crust material (14).
[8]
The geothermal heat extraction system (1) according to the preceding claim, wherein the upper wellbore portion (4) extends between the upper level of the wellbore (5) and the liquid-gas interface (13), the upper portion of the heat pipe extends between the upper level of the heat pipe and the liquid gas interface (13).
[9]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the first heat-conducting material has a heat conductivity of more than 30 W / (mK), preferably more than 100 W / (mK) .
BE2018 / 5307
B E2018 / 5307
[10]
The geothermal heat extraction system (1) according to any of the preceding claims wherein the lower portion of the heat pipe is a heat recovery component.
[11]
The geothermal heat extraction system (1) according to the preceding claim, wherein the heat recovery component is configured to exchange heat between the surrounding earth crust material (3) of the heat recovery component and the heat medium (9) contained in the heat recovery component .
[12]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the geothermal temperatures of the earth's crust material (3) surrounding the lower portion of the heat pipe are at least the boiling temperature of the heat medium (9) ).
[13]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the at least one heat-conducting path (12) extends outwardly from the lower portion of the heat pipe (6) to the earth's crust material (3) that surrounds the lower part of the heat pipe (6).
[14]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the at least one heat-conducting path (12) is a naturally occurring layer in the surrounding crust material (3), the naturally occurring layer has a thermal conductivity of more than 30 W / (mK).
[15]
The geothermal heat extraction system (1) according to any of the preceding claims 1-13, wherein the at least one heat-conducting path (12) is a path which is drilled into the surrounding crust material (3) and
BE2018 / 5307
B E2018 / 5307 is filled with a second heat-conducting material.
[16]
The geothermal heat extraction system (1) according to the preceding claim, wherein the second heat-conducting material has a heat conductivity of at least 30 (W / m.K).
[17]
The system for extracting geothermal heat (1) according to any of the preceding claims 15-16, wherein the heat-conducting path (12) conducts heat via the second heat-conducting material by means of conduction.
[18]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the heat extraction device (11) extracts the heat energy available at the upper wellbore portion (4), and which is carried by the heat medium (10), preferably passively carried by the heat medium (10).
[19]
The geothermal heat extraction system (1) according to the preceding claims, wherein the wall of the heat pipe extends from the lower level of the heat pipe to the upper level of the heat pipe, at least at the upper level of the well bore (5).
[20]
The geothermal heat extraction system (1) according to the preceding claim, wherein the upper level of the heat pipe extends above the upper level of the wellbore (5).
[21]
The geothermal heat extraction system (1) according to any of the preceding claims 1-17, wherein the wall of the heat pipe extends from the lower level of the heat pipe to an upper level of the heat pipe below the upper level of the wellbore (5), gas being released from the earth's crust material and being carried passively to the upper wellbore portion (4).
BE2018 / 5307
B E2018 / 5307
[22]
The geothermal heat extraction system (1) according to the preceding claim, wherein the heat extraction device (11) uses during its operation thermal energy that is available at the upper wellbore portion, and that is passively carried by the released gases.
[23]
The geothermal heat extraction system (1) according to the preceding claim, wherein the released gas comprises methane gas.
[24]
The geothermal heat extraction system (1) according to any of the preceding claims 1-23, wherein the heat extraction device (11) comprises a usable heat circuit for heating a heating system.
[25]
The geothermal heat extraction system (1) according to the preceding claim, wherein the heat extraction device (11) comprises a heat exchanger for indirectly heating the usable heat circuit with heat available in the upper wellbore section (4).
[26]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the geothermal well bore (2) has a well bore depth between the upper level of the well bore (5) and the lower level of the well bore ( 7) has between 1 and 6 kilometers, preferably between 3 and 4 kilometers.
[27]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the geothermal wellbore (2) is a cylindrical geothermal wellbore with a diameter between 1 meter and 30 meters and with a depth of lower wellbore portion (6) between the liquid gas interface (13) and the lower level of the wellbore (7) in the first direction of the geothermal wellbore (2) of between 10 cm
BE2018 / 5307
BE2018 / 5307 and 5 meters, preferably 1 meter and 5 meters.
[28]
The geothermal heat extraction system (1) according to any of the preceding claims, wherein the heat medium (9, 10) contained in the walls of the heat pipe comprises a radioactive heat medium, such as radioactive waste material.
[29]
A method of producing the heat extraction system (1) according to any of the preceding claims, wherein the method comprises the following steps:
• making, such as drilling, the geothermal wellbore (2) in the surrounding earth crust material (3) from the upper level of the wellbore (5) on the surface of the earth crust material (14) to a lower lower level of the borehole (7) at a depth where the surrounding earth crust material (3) exhibits geothermal temperatures higher than temperatures on the surface of the earth crust material (14), • filling the heat pipe with the heat medium (9,10) at least partially that the heat medium (9, 10) is enclosed within the heat pipe by the walls of the heat pipe, • inserting the heat pipe into the geothermal well (2) and • installing the heat extraction device (11) at the upper level of the well bore (5).
[30]
A method of producing the heat extraction system (1) according to the preceding claim, wherein the method comprises the step of making, such as drilling, at least one path (12) extending from the geothermal
BE2018 / 5307
BE2018 / 5307 well (2) into the surrounding earth crust material (3), and filling the at least one path (12) with the second heat-conducting material.
[31]
A method of producing the heat extraction system (1) according to any of the preceding claims 29 to 30, wherein the method comprises the step of introducing the heat pipe into the geothermal well (2) from a lower level from the heat pipe at the lower level of the well bore (7) to an upper level of the heat pipe, at least the upper level of the well bore (5).
[32]
Use of the heat extraction system (1) according to any of the preceding claims 1-28, wherein the heat extraction system is used to extract heat from the surrounding earth crust material (3) of the geothermal wellbore (2) around the heat medium (9, 10) in the geothermal well (2).
[33]
Use of the heat extraction system (1) according to the preceding claim, wherein the heat extraction device (11) uses the heated heat medium (9, 10) to generate electricity.
[34]
Use of the heat extraction system (1) according to any of the preceding claims 32-33, at least in combination with claim 25, wherein the heat extraction device (11) uses the heat exchanger for indirectly heating the usable heat circuit with heat available in the upper wellbore portion (4).

类似技术:

---

公开号 | 公开日 | 专利标题

---

JP2014500420A|2014-01-09|Passive heat extraction and power generation

---

US8650875B2|2014-02-18|Direct exchange geothermal refrigerant power advanced generating system

---

JP2011524484A|2011-09-01|System and method for acquiring geothermal heat for generating electricity from a drilled well

---

US20090211757A1|2009-08-27|Utilization of geothermal energy

---

US20150101779A1|2015-04-16|System and Method of Maximizing Performance of a Solid-State Closed Loop Well Heat Exchanger

---

JP2013164062A|2013-08-22|Geothermal heat exchanger and geothermal power generation device

---

EP3961122A1|2022-03-02|Geothermal energy mining system using stepped gravity-assisted heat pipe having no accumulated liquid effect

---

US20150330670A1|2015-11-19|System and method for utilizing oil and gas wells for geothermal power generation

---

BE1025635B1|2019-05-14|EFFICIENT GEOTHERMAL HEAT ENERGY EXTRACTION SYSTEM

---

US20080223032A1|2008-09-18|Systems And Methods For Generating Electricity Using Heat From Within The Earth

---

RU2621440C1|2017-06-06|Device for converting geothermal energy into electrical energy

---

US4342197A|1982-08-03|Geothermal pump down-hole energy regeneration system

---

US20200217304A1|2020-07-09|Systems and methods of generating electricity using heat from within the earth

---

KR20200107928A|2020-09-16|A system and method for generating electricity using heat from the ground

---

WO2010016919A2|2010-02-11|System and method of maximizing performance of a solid-state closed loop well heat exchanger

---

US8418465B2|2013-04-16|Geothermal heat transfer and intensification system and method

---

CN105546860A|2016-05-04|Device and method for extracting and using geothermal energy

---

JP6085645B2|2017-02-22|Geothermal exchanger and geothermal power generator

---

KR20210031468A|2021-03-19|Method, system and apparatus for extracting thermal energy from geothermal brine fluid

---

WO2021148100A2|2021-07-29|Integrated geothermal tree power plant |

---

KR20180070502A|2018-06-26|apparatus of geothermal power generation

---

CN106321376A|2017-01-11|Method for generating electricity through high-temperature geothermal energy

---

SI23618A|2012-07-31|Gravitational heat pipe for the production of geothermal heat

同族专利:

---

公开号 | 公开日

---

WO2018206712A1|2018-11-15|

---

EP3622228A1|2020-03-18|

---

BE1025635A1|2019-05-08|

---

US20200072506A1|2020-03-05|

---

US11085671B2|2021-08-10|

引用文献:

---

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

---

JPH07286760A|1994-04-15|1995-10-31|Fujikura Ltd|Heat pipe type geothermal heat extractor|

---

JPH07332882A|1994-06-02|1995-12-22|Fujikura Ltd|Mounting device of continuous heat pipe suspension wire|

---

WO2009151649A2|2008-06-13|2009-12-17|Parrella Michael J|System and method of capturing geothermal heat from within a drilled well to generate electricity|

---

US20100276115A1|2008-08-05|2010-11-04|Parrella Michael J|System and method of maximizing heat transfer at the bottom of a well using heat conductive components and a predictive model|

---

US20150013981A1|2013-03-08|2015-01-15|Gtherm Inc.|Creation of SWEGS Appendages and Heat Pipe Structures|

---

US3911683A|1974-12-12|1975-10-14|John H Wolf|Efficient and nonpolluting method for recovering geothermal heat energy|

---

WO2014081911A2|2012-11-21|2014-05-30|Aavid Thermalloy, Llc|System and method for geothermal heat harvesting|

---

TW201629422A|2014-08-25|2016-08-16|席凡索斯公司|Heat capture, transfer and release for industrial applications|CN112113358A|2019-06-19|2020-12-22|中国石油天然气股份有限公司|Deep geothermal development well completion heat extraction device and manufacturing method thereof|

法律状态:
2019-06-13| FG| Patent granted|Effective date: 20190514 |

优先权:

---

申请号 | 申请日 | 专利标题

---

EPPCT/EP2017/061052|2017-05-09|

---

EP2017061052|2017-05-09|

---