SI23618A - Gravitational heat pipe for the production of geothermal heat - Google Patents

Abstract

Gravitational heat pipe for the production of geothermal heat solves the technical problem of exploitation of the heat potential land. The essence of the invention is that the tube wells (2) sequential vapor- tight tubing is inserted, which also includes a set of steam obstruction (6) and plug (9), in implementing the two cases. In the first operative case, the liquid refrigerant in the vapor barrier (6) and area in the evaporator (14) fed in the space (8), out of however, the superficial vapor refrigerant discharged by the ascension pipe(3). The second example is the implementation of the first implementation of the case differ in that they are in the upper part of the tube wells (2) parallel built-in delivery tube (16) and outlet pipe (17), using, first in the vapor barrier (6) and on the evaporator area (14) delivers liquid cooling substance, on the other hand, the vapor refrigerant discharged on the surface. The first implementation example has about 20% better efficiency of the implementation of the second case. Both may be undertaken in existing wells or new, purpose drilled borehole.

Description

GRAVITY HEAT PIPE FOR GEOTHERMAL HEAT PRODUCTION

The subject of the invention

The subject of the invention is a gravity heat pipe for the production of geothermal heat based on the utilization of the thermal potential of the earth.

According to the international patent classification, the claimed invention is envisaged to be classified in F24J3 / 08 and additionally in F28D15 / 02.

A technical problem

A technical problem solved by the invention is such a design of a gravity heat pipe that will allow efficient production of geothermal heat based on the exploitation of the earth's temperature potential up to a depth of 5000 m and using an environmentally friendly heat carrier. The exploitation of the temperature potential of the depths of the earth according to the invention will have a favorable long-term effect on the efficient use of renewable energy sources, while reducing the ecological burden on the environment. At the same time, the construction of the gravity heat pipe will be simple and compact, which can be implemented in existing unproductive oil and gas wells or in new ground wells with a large temperature gradient.

The prior art

With the development of technology and the need to exploit new energy sources, increasing emphasis is being placed on the exploitation of renewable energy sources, including geothermal energy, which is usually the carrier of heat. At lower temperatures it is used for heating buildings, greenhouses, in balneology, for drying and the like, and at higher temperatures for the production of electricity. Due to ecological requirements, in addition to the exploitation geothermal well, a re-injection well has to be carried out, which enables the return of energy-consumed water back into the earth. As a result, the investment costs of implementing such systems are significantly increased, and geothermal water at high temperatures often has a high content of dissolved minerals and CO ₂ , which makes it technically difficult to use. To avoid these drawbacks, a gravity heat pipe is designed to produce the geothermal heat of the present invention, in particular its construction and function.

The production of heat by exploiting the geothermal potential of the earth based on the design of the gravitational heat pipe, the method of its installation and the process of use which are the subject of the present invention is unknown to the applicant.

However, there are some other known solutions to the exploitation of geothermal energy or heat of the earth.

According to documents DE 202004007567, DE 2928414 and DE 4329269, geo-probe soil heat recovery solutions are known. A common feature of these solutions is that they allow the exploitation of the earth's heat by means of geosondes and heat pumps, and are used for low-temperature heating of buildings. The design of geosondes differs from one another in design, but all consider that a U tube or a tube is inserted in the well. Geosondes typically do not exceed a depth of 100 m, where the annual temperature of the Earth's layers is constant and is approximately 10 ° C. For low temperatures and economic reasons, they are only used for low-temperature heating of buildings by means of heat pumps. When performing

geosondes with a U tube a cold liquid is introduced into one well, which is heated in the well and returns to the surface after the other. Pipes that are inserted into a geosound well are usually made of plastic.

JP 59007856 describes a well-known solution for the exploitation of the geothermal potential of the earth, which is made as a thermosyphon, which is essentially a tube-type heat exchanger inserted into the pipe. Water in the thermosyphon circulates in a closed circuit by means of a pump or by the difference in the density of hot and cold water. Cold water is introduced into the interstitial space, between the borehole tube and the center tube, which, when flowing down the hole, heats up and returns to the surface via the insulated center tube. A center tube inserted into the borehole is enclosed on the outside by an insulating liner to minimize heat losses during the circulation of the liquid working fluid. The thermosiphon technical solution for harnessing the geothermal potential of deep wells with high temperature can be used for high temperature heating and / or for the production of electricity. The disadvantage of this solution is that it does not allow the exploitation of the full available temperature potential in the production of electricity. For example, at a water temperature of 100 ° C, only a temperature difference between 100 ° C and 80 ° C can be utilized with this power generation system, ie only ΔΤ 20 ° C, and the remaining low-temperature energy potential remains untapped.

JP 8285480 is a known solution for the exploitation of geothermal energy, where a water-filled heat pipe is inserted into the upper part of the well, which is heated in the lower part of the well and circulates along the heat pipe through the pump system and evaporates the refrigerant therein. Liquid refrigerant, which evaporates in the heat pipe, is discharged as steam into the condenser, where the condensation of the refrigerant vapor produces thermal energy. The solution is based on the supply of liquid coolant into the heat pipe through the center pipe and the discharge of steam through the intermediate interstitial space to the surface. The disadvantage of such a heat pipe design is that due to the formation of high hydrostatic pressure it does not allow the liquid coolant to evaporate along its entire length or depth. The disadvantage of this solution is also in the difficult implementation, that is, in the complicated process of inserting a heat pipe into the well. Another disadvantage is that due to the lower circulating water temperatures that heat the pipe in the higher layers, a portion of the refrigerant vapor begins to condense and return to the bottom of the heat pipe. As a result, only part of the vapor phase of the refrigerant is brought to the surface where their condensation produces heat.

Another well-known solution for the exploitation of geothermal energy is the so-called Advanced Geothermal System (EEC), where high temperature wells are used to produce heat and / or electricity. It consists of two parallel vertical wells, one of which is a production well and the other a reverse, injection well. A heat exchanger installed on the surface of the earth is used for heat removal. Water, which circulates within the system by means of suitable pumps, is used as the working fluid or heat carrier of geothermal energy. The most famous example of the use of EEC technology is described in a pilot scientific research project carried out in Soultz-sous-Fortes, France. This system has the disadvantage of requiring the drilling of two holes that are perforated at the bottom and is only applicable in geothermal areas where porous earth layers do not contain liquid or gaseous fluids that can contaminate the workpiece with impurities. Such geothermal areas on earth are very rare. A disadvantage of this system is the requirement to install special filters and separators to clean solids and gases from the feed fluid. Namely, only clean water should be fed into the return, re-injection well to prevent clogging of porous earth layers.

A common feature of all the known known solutions for the exploitation of geothermal energy is that a cool liquid medium is introduced into the borehole, which returns to the surface of the earth when heated. The problem that remains unsolved is, in particular, the limited geothermal capacity of deep wells, which is a consequence of the flow limitation of the fluid medium due to pressure drop. Limiting the flow velocity of a fluid medium in a well results in less heat input to the surface of the earth. To make the topic • * »··· · · · · · · · · · · · · · · · · · · · · · · · · · · ·,. ·· · ······· A designed gravity heat pipe for geothermal heat production according to the invention has been avoided.

The solution to a technical problem

According to the invention, the technical problem of exploiting the temperature potential of the earth's wells is solved by a gravity heat pipe for the production of geothermal heat and by processes in this connection. The gravitational heat pipe uses refrigerant R717 or R718 as the heat carrier. It is designed as a gas-tight borehole, into which a smaller diameter tube and a larger diameter tube are inserted, with a hydraulic vapor barrier system designed at the depth of the start of evaporation of the refrigerant, which uniformly feeds the liquid refrigerant into the evaporation zone of the gravitational heat pipe. The process of the invention is based on the production of a R717 or R718 refrigerant pair in a gravity heat pipe and the production of geothermal heat by condensing a refrigerant pair on the earth's surface. The heat produced in this way can be used for heating, and also for the production of electricity using accessories.

The invention is explained in more detail by way of two embodiments and the accompanying drawings illustrating FIG. 1 is a first embodiment of a gravitational heat pipe according to the invention in longitudinal section; 2 in the same way as in FIG. 1, only a cross-sectional view of the A-A gravity heat pipe above the vapor barrier FIG. 3 in the same way as in FIG. 1, only an enlarged view of a gravity heat pipe in the vapor barrier region, in the longitudinal section of FIG. 4 the same as in FIG. 3, cross-sectional view only of the B-B vapor barrier FIG. 5 is a second embodiment of a gravitational heat pipe according to the invention in longitudinal section; 6 is the same as in FIG. 5, only a cross-sectional view of the C-C gravity heat pipe above the vapor bar FIG. 7 in the same way as in FIG. 5, only an enlarged view of a gravity heat pipe in the vapor barrier region, in the longitudinal section of FIG. 8 is the same as in FIG. 7, D-D vapor barrier cross section only

The structural design of the two presented versions of the gravity heat pipe for the production of geothermal heat is characterized in that it is useful for exploiting the thermal potential of the earth in wells up to 5000 m deep or more. The design of the gravitational heat pipe is designed to evaporate a coolant by exploiting the geothermal heat of the earth in the well, whose vapor condenses on the surface in the condenser and returns to the well. The condensation of a refrigerant vapor produced by heat is used to produce heat and, using an ORC device, to produce electricity.

The above applies to both embodiments of the invention.

The essence of the claimed invention of a gravity heat pipe for the production of geothermal heat is in the borehole 2, which is sealed at the bottom with a plug 7, a sequentially inserted superimposed steam-tight pipe, the components of which are a vapor barrier 6 and a plug 9. As previously mentioned, it comprises the present invention are two embodiments of a gravity heat pipe that differ from each other in the manner of delivery of the liquid refrigerant and in the manner of discharge of the refrigerant vapor to the surface.

In the first embodiment of the gravitational heat pipe shown in FIG. 1, the liquid refrigerant is introduced into the vapor barrier 6 and further into the evaporation zone 14, through the interstitial space 8, which is located between the borehole pipe 2 and the intermediate pipe 4. The drainage pipe 3, which is located in the intermediate pipe 4, is intended for the removal of a coolant vapor from the evaporation zone 14 to the surface.

In another embodiment, the gravitational heat pipe shown in FIG. 5, the liquid refrigerant is introduced into the vapor barrier 6 and further into the evaporation zone 14 via the inlet pipe 16, which is positioned inside the borehole pipe 2 in parallel with the drainage pipe 17, through which the refrigerant vapors are directed to a condenser located on the earth's surface. .

In both embodiments, gravity heat pipes can be considered to be made in an existing well, a so-called unproductive well, providing a sufficiently large geothermal heat potential, or in a well-drilled hole into which individual components and assemblies of a gravity heat pipe are installed. The joints of the individual tube segments of the borehole tube 2 are gas-tight to prevent vdorfluids present in the earth layers.

Embodiments of the gravity heat pipe of the invention are described in more detail below.

A first embodiment of a gravity heat pipe for producing geothermal heat according to the invention is shown in FIG. 1, FIG. 2, FIG. 3 and FIG. 4. It is a system of pipes or tubes installed in a borehole with a inserted inlet pipe 1 into which a borehole pipe 2 is installed, whose diameter is usually gradually reduced in depth. An assembly of the vapor barrel 6, the plug 9, the drainage pipe 3 and the intermediate tube 4 is inserted into the borehole 2, which is assembled on the ground surface and is lowered into the borehole tube 2 by means of a hermetically sealed seal at the bottom. the intermediate pipe 4 is therefore smaller in diameter than the borehole pipe 2 and larger in diameter than the drainage pipe 3. The pipe 3 is intended for the discharge of hot refrigerant vapor from the evaporation zone 14 to the surface.

The drainage tube 3 and the intermediate tube 4 are thus centrally inserted into the borehole tube 2, thus forming the interconnecting spaces 5 and 8. The intermediate tube 4 is sealed at both ends hermetically with a reducing insert 19. During the tube wells 2 and the intermediate tube 4 is an interconnecting space 8 intended to supply the liquid coolant to the vapor barrier 6 and further to the evaporation zone 14. There is a hermetically sealed interconnecting space 5 between the discharge tube 3 and the intermediate tube 4, which represents vacuum insulation. The description is shown in FIG. 1 and FIG. 2.

The vapor barrier 6 is made under the plug 9 and is located adjacent to the wall of the borehole pipe 2. It consists of a pipe 12, which is closed below with the bottom 13, and a pipe 11, which is connected to the tube space 8. The pipe 11 is intended for supplying liquid refrigerants from • ·

of the tubing space 8 into the vapor barrel 6. The tube 11 is fixed to the plug 9 by the upper end, and its lower end extends into the tube 12 of the vapor barrier 6 and ends slightly above the bottom 13. A perforation 15 is designed into the wall of the tube 12, intended for uniform dispersion of the liquid coolant into the evaporation zone 14 in the borehole pipe 2, which is located below the vapor barrel 6. The perforation 15 is carried out on the upper third of the tube casing 12 and is formed by a number of holes of a suitable size to be made above the lower end of the pipe 11.

The description is shown in FIG. 3 and FIG. 4.

The vapor barrier 6 may also be designed differently from that shown in FIG. 3, which is not specifically shown and described.

The gravity heat pipe according to the first embodiment can also be provided without a steam stop 6, which can be replaced by the installation of a suitable non-return valve at the lower end of the pipe 11.

All pipes 1, 2, 3, 4, 11 and 12 are of standard diameters, the dimensions of which are chosen so that they can be inserted into one another and at the same time allow the necessary flow of fluid within them and through the interstitial space 8.

Referring to the preceding description of the first embodiment of the invention, there is in the upper part of the gravitational heat pipe between the borehole 2 and the intermediate pipe 4 an interstitial space 8, through which a liquid coolant which flows through the pipe 11 is supplied from the surface in the X direction. attached to the plug 9 into the vapor barrel 6. In the vapor barrel 6, the liquid refrigerant partially escapes through the perforation 15, and the remainder flows in the Y direction through the upper edge of the pipe 12 or the surface 10 into the evaporation zone 14. The liquid refrigerant at the downward paths in the evaporation zone 14 evaporate due to the heat flow passing through the wall of the borehole tube 2 from the hot earth layers surrounding it. By evaporation of the coolant, the resulting vapors flow in the Z direction, which is opposite to the liquid phase flow direction in the liquid phase Y direction. The steam in the Z direction at the plug 9 enters the drainage pipe 3, after which it is discharged to the surface.

The evaporation zone 14 extends from the plug 9 above the vapor barrier 6 to the plug 7 at the bottom of the borehole tube 2, with the plugs 7 and 9 sealing zone 14 sealed.

Plug 9 is installed in the borehole tube 2 in order to hermetically separate the upper part of the gravity heat pipe from the lower one, where the refrigerant evaporation takes place.

The plug 9 lies above the vapor barrier 6 and is hermetically inserted and secured into the borehole tube 2. The drainage tube 3 and the pipe 11 are guided through the plug 9. The pipes 3 and 11 are secured to the plug 9 so that the liquid phase in the X direction is passed through the pipe 11 into the vapor barrier 6 and the refrigerant vapor in the Z direction through the drain pipe 3 at surface.

The plug 7, which seals the borehole tube 2 at the bottom, is activated and solidified with a layer of concrete after insertion.

Studs 7 and 9 are standard construction designs because they are used in oil and natural gas extraction technology. The process of their activation is performed according to the manufacturer's instructions.

Following the installation of the plug 7 at the bottom of the borehole pipe 2, the insertion of the steam pipe 11 with the steam seal 6 into the plug 9 is followed by the simultaneous mounting and lowering of the drainage pipe 3 and the intermediate pipe 4. All hermetically sealed components of this assembly are assembled. on the surface of the earth and with a lifting device they lower wells 2.

The choice of coolant as a heat carrier depends on the depth of the borehole or the length of the borehole pipe 2 and on the geothermal heat potential. The most environmentally friendly liquid refrigerant that can be used as a heat carrier in a gravity heat pipe is R717, and R718 can be used at very high temperatures and deep wells. Coolants R290, R600, R600a, R744, R170 or refrigerants commonly used in refrigeration such as R134a, R245fa and the like may also be used to produce heat at lower temperatures and shallow wells.

The amount of geothermal heat produced by the gravity heat pipe of the invention is regulated on the surface by returning an adequate amount of liquid coolant to the well. The optimal depth of installation of the vapor barrier 6 is determined on the basis of a computer simulation of the operation of the gravity heat pipe for each well. The vapor barrier 6 is not required for the operation of the geothermal well above the critical temperature and coolant pressure (super critical coolant), but in this case the drainage pipe 3 must be extended almost to the plug 7 at the bottom of the borehole pipe 2. Intensity of heat transfer from the inner surface of the pipe of the well 2 per coolant depends on the temperature difference, the thermal conductivity of the geological layers of the well and the evaporation surface of the coolant.

Steady-state refrigerant vapor pressure and temperature depend on the temperature, thermal conductivity of the borehole geological layers, and the mass flow rate of the liquid coolant. The heat losses between the liquid and the vapor phase of the coolant above the vapor barrier 6 are prevented by vacuuming the interstitial space 5 between the walls of the drainage pipe 3 and the intermediate pipe 4. This reduces heat losses and prevents condensation of the refrigerant vapor from flowing through the central drainage pipe 3 to surface. Air and water must be removed from the well before filling the gravity heat pipe with a coolant.

A structural embodiment of a gravity tube for the production of geothermal heat according to another embodiment of the invention is shown in FIG. 5 to and including FIG. 8. It is a system of pipes or tubes fitted into a borehole with an inserted inlet pipe 1 into which a borehole pipe 2 is installed, the diameter of which is usually gradually reduced in depth. An assembly of the vapor barrel 6, the plug 9, the locking element 18, the inlet pipe 16 and the discharge pipe 17 is inserted into the borehole tube 2 and assembled on the surface of the earth and lowered into the borehole pipe 2, which is sealed with the plug at the bottom. 7. In this case, the discharge pipe 17 is smaller than the borehole pipe 2 and larger than the feed pipe 16. The feed pipe 16 is intended for supplying the liquid refrigerant to the vapor barrier 6 and through it to the evaporation zone 14, via the discharge pipe. 17, however, hot refrigerant vapors are discharged from the evaporation zone 14 to the surface.

The inlet pipe 16 and the outlet pipe 17 are inserted parallel to one another in the borehole tube 2, forming a tubular space 5, which is sealed on each side by a plug 9 and a sealing element 18. The tubular space 5 is a vacuum insulation. The description is shown in FIG. 1 and FIG. 2.

The vapor barrier 6, which is made under the plug 9 and located adjacent to the wall of the borehole tube 2, forms a tube 12 with the bottom 13 and a supply pipe 16 that passes through the plug 9 through the interstitial space 5 from the surface of the earth. The inlet pipe 16 is attached to the closure element 18 by the upper end and the plug end 9 to the lower end and leads to a vapor barrier 6. A perforation 15 is carried out into the wall of the pipe 12, the purpose of which is to disperse the liquid coolant evenly into the evaporation zone 14 in the pipe bore 2, which is located below the vapor barrier 6. The perforation 15 is made on the upper third of the tube sleeve 12 and is formed by a number of holes of a suitable size to be provided above the lower end of the supply pipe 16.

The description is shown in FIG. 7 and FIG. 8.

The vapor barrier 6 may also be designed differently from that shown in FIG. 3, which is not specifically shown and described.

According to another embodiment, the gravity heat pipe may also be provided without a steam stop 6, which may be replaced by the installation of a suitable non-return valve at the lower end of the supply pipe 16.

All tubes 1, 2, 12, 16 and 17 are standard diameters, the dimensions of which are chosen so that they can be inserted side by side while allowing the necessary fluid flow.

Referring to the foregoing description of another embodiment of the invention, there is a vacuum space 5 in the upper part of the gravitational heat pipe, that is, in the borehole pipe 2 and between the feed pipe 16 and the discharge pipe 17.

Liquid refrigerant is introduced into the vapor barrier 6 from the supply line 16 in the direction of the inlet pipe 16, which passes through the plug 9 and the closure element 18. From the vapor barrier 6, the liquid refrigerant partly flows through the perforation 15 into the evaporation zone 14 into which the evaporation zone 14 in the Y direction and over the edge of the pipe 12 with a level 10, the remainder of the liquid coolant also overflows. The liquid refrigerant on the way down in the evaporation zone 14 evaporates due to heat flowing through the wall of the borehole tube 2 from the hot earth layers surrounding it. By evaporation of the refrigerant, the vapor produced flows in the Z direction upwards, which is opposite to the flow direction of the liquid phase Y. The vapor at the plug 9 in the Z direction enters the drainage pipe 17, after which it is discharged to the surface.

The evaporation zone 14 extends from the plug 9 above the vapor barrier 6 to the plug 7 at the bottom of the borehole tube 2 and is sealed by the plugs 7 and 9.

The plug 9 is mounted in the borehole pipe 2 in order to hermetically separate the upper part of the gravity heat pipe from the lower one, where the refrigerant evaporation takes place, and is placed above the vapor barrier 6.

The plug 9 and the locking element 18 hermetically seal the tubular space 5, which represents vacuum insulation.

A drain pipe 17 and a supply pipe are passed through the plug 9 and the locking element 18

16. The tubes 16 and 17 are secured to the plug 9 and the closure element 18 to allow the flow of liquid refrigerant in the X direction through the inlet pipe 16 into the steam stop 6 and the flow of the refrigerant pair in the Z direction through the drain pipe 17 to the surface.

The plug 7, which seals the borehole tube 2 at the bottom, is activated and cured with a layer of concrete after insertion.

Plugs 7 and 9 and locking element 18 are standard construction designs and are used in oil and natural gas extraction technology. The process of their activation is performed according to the manufacturer's instructions. The locking element 18 is specially designed for this purpose.

After the plug 7 is installed at the bottom of the borehole pipe 2, insertion of the supply pipe 16 with a steam stop 6 into the plug 9 is followed by the simultaneous installation and lowering of the supply pipe 16 and the drainage pipe 17. All components of this assembly are hermetically connected and assembled at the surface of the earth and are lowered by a lifting device into the borehole 2.

The conditions for selecting a refrigerant as a heat carrier are the same as in the first embodiment.

In fact, the second embodiment differs from the first embodiment of the gravity heat pipe for the production of geothermal heat in that parallel pipes 16 and 17 are installed side by side in the upper part of the borehole pipe 2 and 17. Liquid pipe 16 is supplied from the surface with a smaller diameter. refrigerant through the plug 9 to the vapor barrier 6, and vapor coolant vapors are discharged to the surface via the outlet pipe 17 of a larger diameter through the evaporation zone 14 in the borehole tube 2. The rest of the construction is the same as in the first embodiment. The same applies to the installation of components in the borehole tube 2.

The second embodiment of the geothermal gravity heat pipe has, according to the first embodiment, about 20% lower efficiency of the geothermal well potential.

Claims (15)

Gravity heat pipe for producing geothermal heat according to the first embodiment, characterized in that a vapor barrier assembly (6), a plug (9), a discharge pipe (3) and an intermediate pipe (4) are inserted into the borehole tube (2). ), which consists entirely of the surface of the earth and is lowered by a lifting device into the borehole pipe (2) to a depth determined by the length of the interconnected successive segments of the drainage pipe (3), the steam barrier (6) being by the pipe ( 11) located below the plug (9) within the evaporation zone (14); that the vapor barrier (6) comprises a tube (12) with perforation (15) and a bottom (13) and a tube (11) which is secured to the plug (9) with the upper end and extends into the tube (12) with the lower end; ends slightly above the bottom (13); that the drainage tube (3) and the intermediate tube (4) are centrally inserted into the borehole tube (2), so that the intermediate tube (4) is sealed to the drainage tube (3) at both ends through the reducing inserts (19). ), with the tubes forming interconnecting spaces (5) and (8). Gravity heat pipe according to claim 1, characterized in that the diameter of the intermediate pipe (4) is smaller than the diameter of the borehole pipe (2) and larger than the diameter of the drainage pipe (3). 3. Gravity heat pipe for the production of geothermal heat according to another embodiment, characterized in that a vapor barrier assembly (6), a plug (9), a stop element (18), a supply pipe (16) are inserted into the borehole tube (2). ) and a drainage pipe (17), which is assembled on the ground surface and is lowered by a lifting device into the borehole pipe (2) to a depth determined by the length of the sewerage pipe segments (17) connected in series, with the steam lock ( 6) fitted with a supply pipe (16) inside the evaporation zone (14) under the plug (9); that the vapor barrier (6) comprises a pipe (12) with perforation (15) and a bottom (13) and a supply pipe (16) which is secured to the plug (9) with the upper end and extends into the pipe (12) with the lower end. so that it ends slightly above the bottom (13); that a supply pipe (16) and a drainage pipe (17) are positioned parallel to each other in a borehole pipe (2) in such a way that they are hermetically inserted into the borehole pipe (2) via the plug (9) and the locking element (18); in this way, the tubes form an intertidal space with each other (5). Gravity heat pipe according to claim 1, characterized in that the diameter of the drainage pipe (17) is smaller than the diameter of the borehole pipe (2) and larger than the diameter of the supply pipe (16). Gravity heat pipe according to claim 1 or 3, characterized in that the plug (9) and the plug (7) hermetically close the evaporation zone (14). Gravity heat pipe according to claim 1 or 3, characterized in that the hermetically sealed interconnector (5) is vacuum insulated. Gravity heat pipe according to claim 1 or 3, characterized in that the perforation (15) in the wall of the pipe (12) is arranged so that it is located above the lower end of the pipe (11) or the supply pipe (16). Gravity heat pipe according to claim 1 or 3, characterized in that the steam stop (6) can be replaced by a suitable non-return valve mounted on the lower end of the pipe (11) or the supply pipe (16). Gravity heat pipe according to claim 1 or 3, characterized in that the vapor barrier (6) is mounted below the cap (9), the optimal depth of vapor barrier installation (6) being determined by computer simulation of operation for each well separately. Gravity heat pipe according to claims 1 and 3, characterized in that the environmentally friendly liquid coolant R717 is used as the heat carrier, and R718 at very high temperatures and deep holes. Method for the production of geothermal heat by means of a gravitational heat pipe according to the first embodiment, characterized in that the liquid coolant is supplied through the tube space (8) through the tube (11) in the X direction to and from the vapor barrier (6). the evaporation region (14), partly through the perforation (15), and the remainder flows over the upper edge of the tube (12) in the Y direction. Method according to claim 11, characterized in that in the evaporation zone (14) the liquid coolant is evaporated and is fed into the condenser on the surface in the direction of X as a heated steam via the drainage pipe (3). 13. A process for the production of geothermal heat by a gravity heat pipe according to another embodiment, characterized in that the liquid coolant • is fed via the inlet pipe (16) in the X direction directly into the vapor barrier (6) and through it through the perforation ( 15) and through the upper edge of the tube (12) in the Y direction to the evaporation zone (14). Method according to claim 13, characterized in that in the evaporation zone (14) the liquid coolant is evaporated and is fed into the condenser on the surface in the Z direction via a heated vapor (17). A method according to claim 11 or 13, characterized in that the heat losses between the liquid and the vapor phase of the coolant are reduced by vacuuming the tubular space (5), thus preventing condensation of the refrigerant vapor in the drain pipe (3) or in the drain tube (17).