JP2017210888A - Ground heat recovery device including three or more u-shaped inner pipe - Google Patents

Abstract

PURPOSE: To provide a ground heat recovery device including three or more U-shaped inner pipe, capable of efficiently exchanging heat between ground heat and fluid flowing underground for heat exchange with ground heat.CONSTITUTION: A ground heat recovery device includes: an outer pipe to which ground heat is transmitted under the ground, and whose lower portion containing at least a bottom part is blocked; and three or more U-shaped inner pipes arranged in the outer pipe. The three or more U-shaped inner pipes each are configured to circulate fluid between themselves and ground load equipment with heat exchanged between their insides and ground heat. The three or more U-shaped inner pipes are arranged so as to deviate from their positions in a gravity direction and cross with each other in a horizontal direction, in the outer pipe.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a geothermal recovery apparatus that can be used in a geothermal power generation system or the like.

  Conventionally, a geothermal power generation system that collects steam and hot water from geothermal heat from a production well excavated to a geothermal reservoir and uses it for power generation on the ground has been put into practical use. FIG. 5 is a diagram showing an example of such a conventional geothermal power generation system. In the conventional example shown in FIG. 5, after hot water and geothermal steam taken out from the production well 1 are separated by the separator 3, the turbine 4 is driven by the separated steam to generate power by the generator 5 and used for power generation. The steam is cooled by the cooling water in the condenser 6 to be condensed, and is reduced into the ground from the reduction well 2 together with the hot water from the separator 3.

JP 2010-270679 A Japanese Patent No. 4485465

  However, in the conventional geothermal power generation system as shown in FIG. 5 described above, hot water or steam from the geothermal reservoir is passed through the strainer (part having a large number of slits or holes) of the production well 1 into the production well 1. Since it was directly taken in and pumped up to the ground and used for power generation (partially returned to the ground with the reduction well 2), it has an adverse effect on the groundwater system around the geothermal reservoir, such as depleting nearby hot springs. In the process of geothermal power generation, components such as hot water from the geothermal reservoir or sulfur in the steam adhere to and accumulate on the equipment used for geothermal power generation as a scale, and the piping etc. deteriorates or removes a large amount of scale. There were problems such as maintenance costs.

  By the way, in order to solve such problems, a circulation type geothermal power generation system as shown in FIG. 6 has been invented (Japanese Patent Application No. 2014-239236). In FIG. 6, 11 is made of, for example, stainless steel (other materials may be used as long as they have good thermal conductivity) embedded in the geothermal reservoir 13 at a depth of about 300 to 600 m, for example, about 500 m in the ground. Outer pipe (This outer pipe 11 is a hot spring well pipe buried in the ground and used for hot spring wells in the past, but is currently not used as a hot spring well pipe. , 12 is an inner tube made of, for example, stainless steel, which is disposed in the outer tube 11, and an inner tube whose bottom 12c or its vicinity is open. In FIG. 6, the outer tube 11 has an inner diameter of, for example, 30 mm, and the side and lower portions are all closed. The inner tube 12 has an inner diameter of 15 mm, for example, and has an upper end opening 12b and a bottom (lower end) 12a as openings. The bottom portion 12c of the inner tube 12 is disposed at a position (for example, a position above about 100 m) near the bottom portion 11a of the outer tube 11 (or its upper surface 11aa).

  In the geothermal power generation system of FIG. 6, a fluid such as industrial water (which may be a heat medium) is lowered in the gap 15 between the outer tube 11 and the inner tube 12, and the bottom 12c of the inner tube 12 and the The geothermal heat in the external geothermal reservoir 13 is transferred to the bottom vicinity region 14 having a length of, for example, about 100 m between the outer tube 11 and the bottom tube 11 while flowing in the bottom vicinity region 14. After the heat is exchanged to become hot hot water, the inside of the inner pipe 12 rises in the ground direction.

  In the system of FIG. 6, the reference numeral 16 indicates that the hot water that has been lowered in the inner pipe 12 and exchanged with the geothermal heat in the region 14 near the bottom in the outer pipe 11 has risen to the ground in the inner pipe 12. An evaporator supplied via the upper end side opening 12b of the inner pipe 12 and heating (and depressurizing) the hot water to generate steam, 17 is driven by the steam from the evaporator 16 Turbine for power generation, 17a is a generator driven by the turbine 17, 18 is a condenser for returning the steam used to drive the turbine 17 to water, 19a is water from the condenser and the evaporator A water storage tank 19 temporarily stores the hot water separated from the steam in 16, and 19 adds hot water from the water storage tank 19 a into the gap 15 between the outer pipe 11 and the inner pipe 12 from the upper end side opening 11 b. Circulating pump for pressure injection It is. In the geothermal power generation system of FIG. 6, reference numeral 20 denotes the inner pipe 12, a bottom vicinity region 14 in the outer pipe 11, a gap 15 between the inner pipe 12 and the outer pipe 11, the evaporator 16, the turbine 17, It is a closed flow path connecting the condenser 18 and the water storage tank 19a, and is a closed flow path through which the hot water is circulated by the circulation pump 19.

  By the way, in the circulation type geothermal power generation system (FIG. 6) as described above, the hot water or the steam itself in the geothermal reservoir 13 is not pumped up to the ground, so that the nearby hot springs are depleted, for example, around the geothermal reservoir 13 Components such as sulfur contained in the hot water or steam in the geothermal reservoir 13 can be fixed and deposited on the device as a scale during the process of geothermal power generation, which can avoid adversely affecting the groundwater system. There is a merit that it is possible to prevent deterioration of piping and the like due to, and increase in running cost for removing scale. However, also in the above-mentioned circulation type geothermal power generation system (FIG. 6), the circulated water or the like is not generated in the gap 15 between the outer tube 11 and the inner tube 12 and the bottom vicinity region 14 in the outer tube 11. There has been a strong demand to further improve the heat exchange efficiency during heat exchange.

  The present invention was made paying attention to such a problem, and fluid such as water circulated for heat exchange with geothermal heat is more efficiently exchanged with geothermal heat in the underground pipe. An object of the present invention is to provide a geothermal recovery apparatus.

  The geothermal recovery apparatus having three or more U-shaped inner pipes according to the present invention for solving the above-described problems is an outer pipe through which geothermal heat is conducted in the underground, and at least a lower part including the bottom is blocked. And three or more U-shaped inner pipes disposed in the outer pipe, and each of the three or more U-shaped inner pipes is a fluid (for example, a power generation turbine). Between the load equipment on the ground (for example, the power generation turbine), while the fluid that becomes the steam that drives the steam or the fluid that generates the steam that drives the power generation turbine) It is configured to circulate in a circulating manner.

  Further, in the present invention, each of the three or more U-shaped inner pipes is such that each side surface thereof is close to or abuts on the inner wall surface of the outer pipe, and each bottom part is the bottom part of the outer pipe or its vicinity ( It may be arranged so as to be located above the bottom of the outer tube 11 (including within a range of about several tens to 200 m).

  In the present invention, the three or more U-shaped inner pipes may be arranged in the outer pipe while being shifted in the direction of gravity and intersecting each other in the horizontal direction.

  Furthermore, in the present invention, the gap between the outer tube and the three or more U-shaped inner tubes may be filled with a material having good thermal conductivity.

  In the present invention, three or more U-shaped inner pipes are arranged inside the outer pipe through which geothermal heat is conducted underground, and the fluid is conducted to the outer pipe while fluid flows through each of the U-shaped inner pipes. Exchanged with geothermal heat. In this case, according to the present invention, the flow distance of the fluid when the fluid flows through each U-shaped inner pipe and is exchanged with the geothermal heat conducted and held by the outer pipe is, for example, “the outer pipe and its When fluid is circulated in a “gap between linear pipes (not U-shaped pipes) arranged inside” (in the case shown in FIG. 6, fluid circulation when the fluid is heat-exchanged in this case) The distance extends substantially twice as much as the distance of the outer tube stays below the length of the outer tube in the gravitational direction. Therefore, according to the present invention, for example, compared with a case where a fluid is circulated in a gap between an outer tube and a linear (not U-shaped) inner tube disposed therein (as shown in FIG. 6). And the heat exchange efficiency with the geothermal heat of the said fluid (fluid which distribute | circulates each said U-shaped inner pipe | tube) in the said outer pipe | tube can be improved significantly.

  Further, in the present invention, the three or more U-shaped inner pipes are arranged such that the respective outer side surfaces thereof are close to or abut against the inner wall surface of the outer pipe, and the bottom parts thereof are the bottom parts of the outer pipes. Or, when arranged so as to be located in the vicinity thereof, the geothermal heat conducted and held in the outer pipe can be efficiently conducted to the three or more U-shaped inner pipes and the fluid inside thereof. Therefore, the efficiency of heat exchange with the geothermal heat of the fluid (fluid flowing in each U-shaped inner tube) in the outer tube can be further increased.

  In the present invention, when the three or more U-shaped inner pipes are arranged in the outer pipe while being shifted in the direction of gravity and intersecting each other in the horizontal direction, As a result of being able to efficiently arrange a plurality of U-shaped inner tubes in the space, the number of U-shaped inner tubes that can be arranged in the outer tube can be increased, so that the fluid ( The heat exchange efficiency with the geothermal heat of the fluid flowing through each U-shaped inner pipe can be further increased.

  Furthermore, in the present invention, when the gap between the outer tube and the three or more U-shaped inner tubes is filled with a material having good thermal conductivity (substance such as water), the outer tube Conducted and retained geothermal heat can be more efficiently conducted to the three or more U-shaped inner pipes and the fluid inside thereof through the material filled in the gap.

(A) is the schematic which includes a cross section in part for demonstrating the geothermal recovery apparatus provided with the three U-shaped inner pipes which concern on embodiment of this invention, (b) is the AA 'line cross section FIG. It is a figure for demonstrating the arrangement method in three U-shaped inner pipes used for manufacture of this embodiment, and those outer pipes. It is a figure for demonstrating the arrangement method in three U-shaped inner pipes used for manufacture of this embodiment, and those outer pipes. It is a figure for demonstrating the arrangement method in three U-shaped inner pipes used for manufacture of this embodiment, and those outer pipes. It is the schematic for demonstrating an example of the conventional geothermal power generation system. It is the schematic which shows the circulation type geothermal power generation system (Japanese Patent Application No. 2014-239236) invented although it is not yet well-known.

  Hereinafter, a geothermal recovery apparatus according to an embodiment of the present invention will be described with reference to the drawings (in FIG. 1 and the like, parts common to FIG. 6 are assigned the same reference numerals). FIG. 1A is a schematic diagram including a cross section in part for explaining a geothermal recovery apparatus including three U-shaped inner pipes according to an embodiment of the present invention, and FIG. It is A 'sectional view. In Fig.1 (a), 11 is an outer pipe | tube embed | buried to the depth of 50-1500m in the ground, for example, 500m. The outer diameter of the outer tube 11 is, for example, about 200 to 300 mm.

  In FIG. 1, reference numeral 12 denotes an inner tube disposed in the outer tube 11, which is formed by bending two parallel and elongated side tubes 12a and 12b at the bottom 12c. It is a letter-shaped inner tube. The bottom portion 12 c of the U-shaped inner tube 12 is disposed in the vicinity of the bottom portion 11 a of the outer tube 11. In the U-shaped inner tube 12, two parallel and elongated side tubes 12 a and 12 b are arranged such that the outer side surfaces (outer wall surfaces) 12 aa and 12 ba approach (or abut) the inner wall surface of the outer tube 11. Is arranged. The above configuration is the same for the other two U-shaped inner tubes 13 and 14 (the other two U-shaped inner tubes 13 and 14 are not shown in detail in FIG. Will be described later).

  FIG. 1 shows an example in which the present embodiment is applied to a circulation type geothermal power generation system as shown in FIG. 6, for example. In FIG. 1, the U-shaped inner pipe 12 has a circulating pump 19 connected to one upper end opening 12ab by a pipe 20 and an evaporator 16 connected to the other upper end opening 12bb. The circulation pump 19 and the evaporator 16 are connected to each other by a pipe 20 via a power generation turbine 17 and a condenser 18. Thereby, a closed flow path is formed by the evaporator 16, the power generation turbine 17, the condenser 18, the water storage tank 19 a, the circulation pump 19, and the U-shaped inner pipe 12. The same applies to the other two U-shaped inner tubes 13 and 14.

  Among the other two U-shaped inner tubes 13 and 14 arranged in the outer tube 11, the U-shaped inner tube 13 is formed in the U-shape as shown below in the outer tube 11 of FIG. Above the bottom portion 12c of the inner tube 12 (that is, with the position slightly shifted upward in the direction of gravity), and the two side tubes on the sides are only about 120 degrees in the horizontal direction with respect to the U-shaped inner tube 12 It arrange | positions so that it may become a crossing direction (refer FIG.1 (b)). Of the other two U-shaped inner tubes 13, 14, the U-shaped inner tube 14 is positioned above the bottom of the U-shaped inner tube 13 (that is, slightly shifted upward in the direction of gravity). ) And the two side pipes on the side are arranged so as to intersect the U-shaped inner pipes 12 and 13 by about 120 degrees in the horizontal direction (see FIG. 1B). (Note that the other two U-shaped inner tubes 13 and 14 are not shown in detail in FIG. 1, but will be described later with reference to FIG. 2 and subsequent figures).

  Further, in the gap between the outer tube 11 and the three U-shaped inner tubes 12 to 14, the geothermal heat conducted and held in the outer tube 11 is transmitted to the U-shaped inner tubes 12 to 14. In order to facilitate this, a material having good thermal conductivity, such as water, is filled.

  Next, the configuration of the three U-shaped inner pipes 12 to 14 will be described with reference to FIGS. 2 to 4, for convenience of illustration, the length in the gravity direction of the outer tube 11 and the three U-shaped inner tubes 12 to 14 is shown to be shorter than the actual length.

  FIG. 2A is a perspective view showing one U-shaped inner tube 12 among the three U-shaped inner tubes 12 to 14, and FIG. 2B is an outer tube on which the U-shaped inner tube 12 is arranged. 11 is a plan view showing a state in which only the U-shaped inner tube 12 is disposed in the outer tube 11 for the time being. As shown in FIG. 1C, the outer side surfaces (outer wall surfaces) 12aa and 12ba of the two side tubes 12a and 12b of the U-shaped inner tube 12 are close to (or are close to) the inner wall surface 11b of the outer tube 11 (or It is arranged so as to make contact.

  Next, FIG. 3A is a perspective view showing two U-shaped inner tubes 12 and 13 in the three U-shaped inner tubes 12 to 14, and FIG. 3B is the two U-shaped inner tubes. 12 is a side cross-sectional view of the outer tube 11 on which 12 and 13 are disposed, and FIG. 8C is a plan view showing a state in which the two U-shaped inner tubes 12 and 13 are disposed in the outer tube 11 for the time being. As shown in FIG. 3 (a), the bottom 13 c of the U-shaped inner tube 13 is above the bottom 12 c of the U-shaped inner tube 12 among the two U-shaped inner tubes 12, 13. It is arranged at a position (that is, at a position slightly shifted upward in the direction of gravity).

  As shown in FIG. 3C, the two U-shaped inner pipes 12 and 13 are arranged so as to intersect each other by about 120 degrees in the horizontal direction. As a result, the outer side surfaces (outer wall surfaces) 13aa and 13ba of the two side tubes 13a and 13b of the U-shaped inner tube 13 are respectively connected to the outer sides of the two side tubes 12a and 12b of the U-shaped inner tube 12. Similarly to the side surfaces (outer wall surfaces) 12aa and 12ba, the inner wall surface 11b of the outer tube 11 is disposed so as to come close (or abut).

  Next, FIG. 4A is a perspective view showing the three U-shaped inner tubes 12 to 14, and FIG. 4B is the outer tube 11 on which the three U-shaped inner tubes 12 to 14 are arranged. FIG. 3C is a side sectional view showing the state in which the three U-shaped inner tubes 12 to 14 are arranged in the outer tube 11. 4A, among the three U-shaped inner tubes 12 to 14, the bottom portion 14c of the U-shaped inner tube 14 is located above the bottom portion 13c of the U-shaped inner tube 13. (That is, at a position slightly shifted upward in the direction of gravity).

  Further, as shown in FIG. 4C, the three U-shaped inner tubes 12, 13, and 14 are arranged so as to cross each other in the horizontal direction sequentially by about 120 degrees. As a result, as shown in FIG. 4 (c), all of the outer side surfaces (outer wall surfaces) of the respective side tubes of the three U-shaped inner tubes 12 to 14, that is, (i) the U-shape The outer side surfaces (outer wall surfaces) 12aa, 12ba of the two side tubes 12a, 12b of the inner tube 12 (ii) The outer side surfaces (outer wall surfaces) of the two side tubes 13a, 13b of the U-shaped inner tube 13 ) 13aa, 13ba, and (iii) The outer side surfaces (outer wall surfaces) 14aa, 14ba of the two side tubes 14a, 14b of the U-shaped inner tube 14 are connected to the inner wall surface 11b of the outer tube 11, respectively. It arrange | positions so that it may adjoin (or contact | abut).

  Next, the operation of this embodiment will be described with reference to FIG. In the present embodiment, water is pressurized and injected from the upper end opening (for example, reference numeral 12ab in FIG. 1) of each of the three U-shaped inner pipes 12 to 14 by the circulation pump 19. (See arrow A in FIG. 1). The U-shaped inner pipe 12 will be described. The water injected under pressure is lowered in one side pipe 12a of the U-shaped inner pipe 12 (see arrow B in FIG. 1). 11 (inside the bottom vicinity region 11c) of 11 (see arrow C in FIG. 1), reverse, and ascend in the other side tube 12b (see arrow D in FIG. 1). As described above, the water descends in one side pipe 12a (see arrow B in FIG. 1) and descends to the bottom 12c (see arrow C in FIG. 1) and further rises in the other side pipe 12b (see FIG. 1). In the process (see arrow D in FIG. 1), heat is exchanged with the geothermal heat conducted and held in the outer pipe 11 (geothermal heat conducted and held from the underground geothermal reservoir to the outer pipe 11) to become hot water.

  The hot water subjected to heat exchange as described above rises in the other side pipe 12b by the force of the circulation pump 19, and then evaporates from the other upper end side opening 12bb of the U-shaped inner pipe 12. Supplied to the vessel 16. The hot water supplied to the evaporator 16 is converted into steam there, rotates the power generation turbine 17, and then circulates from the condenser 18 to the circulation pump 19 through the water storage tank 19 a. The hot water is further pressurized and injected into the one side pipe 12a of the U-shaped inner pipe 12 from the upper end side opening 12ab of the U-shaped inner pipe 12 by the circulation pump 19, and thereafter It circulates in the closed flow path as described above. In the present embodiment, when hot water is continuously circulated as described above, the temperature of the circulated hot water is approximately 50 to 60 ° C.

  Although the above description has been made with respect to the U-shaped inner tube 12, the same operation as described above is performed with respect to the other two U-shaped inner tubes 13, 14, and the water flows in the closed flow path in the same manner as described above. It circulates to.

  As described above, according to the present embodiment, unlike the conventional example (example shown in FIG. 5), the hot water or steam in the geothermal reservoir 13 is not directly pumped to the ground. It is possible to avoid the inconvenience of adversely affecting the groundwater system near the geothermal reservoir, such as depletion of hot springs. Further, according to the present embodiment, unlike the conventional example (example shown in FIG. 5), the hot water or steam in the geothermal reservoir 13 is not directly pumped to the ground. Components such as sulfur contained in the hot water or steam from the geothermal reservoir are fixed and deposited as scales on equipment used for geothermal power generation, etc., and pipes etc. deteriorate and large maintenance is required to remove the scales It is possible to avoid the disadvantage that costs are incurred.

  In the present embodiment, three U-shaped inner tubes 12 to 14 are arranged inside the outer tube 11 through which geothermal heat is conducted in the underground, and water flows through each of the U-shaped inner tubes 12 to 14. However, heat exchange with the geothermal heat conducted to the outer tube 11 is performed. In this case, according to the present embodiment, the water circulation distance when the heat is exchanged with the geothermal heat conducted to the outer pipe 11 while water flows through each of the U-shaped inner pipes 12 to 14 is, for example, “ When fluid is circulated in the “gap between the outer tube 11 and a straight (not U-shaped) inner tube disposed therein” (in the case shown in FIG. 6, water is exchanged in this case) The flow distance of water at that time is substantially less than the length of the outer tube 11 in the direction of gravity), and the water will extend substantially twice as much. Therefore, according to the present embodiment, for example, when fluid is circulated in the “gap between the outer tube 11 and a linear (not U-shaped) inner tube disposed therein” (shown in FIG. 6). Compared with the case), the heat exchange efficiency with the geothermal heat of the water in the outer pipe 11 (water flowing through the U-shaped inner pipes 12 to 14) can be greatly improved.

  In the present embodiment, the three U-shaped inner tubes 12 to 14 are respectively connected to the outer side surfaces thereof (for example, reference numerals 12aa, 12ba, 13aa, 13ba, 14aa, and 14ba in FIG. 4C). (Refer to reference numerals 12c, 13c, and 14c in FIG. 4 (a)) so that each of the bottom portions (see, for example, reference numerals 12c, 13c, and 14c) of the outer tube 11 Since it is arranged so as to be located at the bottom portion 11a or in the vicinity thereof, the geothermal heat conducted to the outer tube 11 is efficient with respect to the three U-shaped inner tubes 12 to 14 and the water inside thereof. The heat exchange efficiency with the geothermal heat of the water (water flowing through the U-shaped inner pipes 12 to 14) in the outer pipe 11 can be further increased.

  In the present embodiment, the three U-shaped inner pipes 12 to 14 are arranged in the outer pipe 11 while shifting their positions in the gravitational direction and intersecting each other in the horizontal direction ( 4 (a)), the three U-shaped inner tubes 12 to 14 can be efficiently arranged in the space in the outer tube 11, and the water in the outer tube 11 (each of the above-mentioned The heat exchange efficiency with the geothermal heat of water flowing through the U-shaped inner pipes 12 to 14 can be further increased.

  Furthermore, in this embodiment, since the gap between the outer tube 11 and the three U-shaped inner tubes 12 to 14 is filled with a material having good thermal conductivity, for example, water, The conducted and retained geothermal heat can be more efficiently conducted to the three U-shaped inner pipes 12 to 14 and the water therein.

  Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made. For example, in the above-described embodiment, the U-shaped inner tube for exchanging heat with the geothermal heat conducted and held in the outer tube 11 while flowing a fluid such as water is replaced with the three U-shaped inner tubes 12 to 14. However, in the present invention, the number is not limited to this, and any number of four, six, eight, etc. can be used.

  Further, for example, in the above-described embodiment, the example in which the outer tube 11 is directly embedded in the ground has been shown, but the present invention is not limited to this, for example, a depth of 500 m or more in the ground, for example. A hot spring well pipe buried in the past and used in the past for hot spring wells but not currently used for hot spring wells (in the lower part, an external geothermal reservoir 13 The outer pipe 11 and the like are arranged inside a strainer having a large number of slits or holes for introducing hot water and steam therein (hot spring well pipe). Also good.

  Further, in the example shown in FIG. 1 (the example in which the embodiment is applied to a circulation type geothermal power generation system as shown in FIG. 6), the geothermal heat is passed through the three U-shaped inner pipes 12-14. (The geothermal heat conducted from the geothermal reservoir to the outer tube 11) and the hot water exchanged with the heat are raised to the ground and vaporized by the evaporator 16, and the power generation turbine 17 is driven by this vapor. However, the geothermal power generation system to which the present invention is applicable is not limited to this. For example, after the hot water exchanged with the geothermal heat is raised to the ground, the hot water is The low boiling point heat medium is supplied to the primary side of the evaporator for vaporizing, the low boiling point heat medium steam is taken out from the secondary side of the evaporator, and the low temperature boiling point heat medium steam is used to generate a power generation turbine. It is also possible to adopt a driving binary power generation method In this case, the hot water heat-exchanged with the geothermal heat inside the three U-shaped inner pipes 12 to 14 evaporates after rising up to the ground in the three U-shaped inner pipes 12 to 14, for example. Is used to evaporate the heat medium, and is then press-fitted into, for example, the three U-shaped inner pipes 12 to 14 by a circulation pump. The hot water after the replacement only circulates in the closed flow path provided with the three U-shaped inner pipes 12 to 14, the evaporator, the circulation pump and the like as described above, thereby driving the power generation turbine. In such a case, since the geothermal energy existing in the geothermal reservoir 13 outside the outer tube 11 is weak, the geothermal energy contained in the hot water remains relatively small. Even in such a case, a low boiling point heat medium is vaporized by an evaporator. It becomes readily possible to generate power by driving the power generating turbine with a).

  Moreover, in the said embodiment, although the fluid press-fitted by the said circulation pump 19 and heat-exchanged with geothermal heat in the three U-shaped inner pipes 12-14 was made into water, in this invention, other various kinds Other fluids (including heat media) can be used. Moreover, although the said embodiment demonstrated the case where the outer pipe | tube 11 was embed | buried to 50-1500m in the ground, for example, about 500m, in this invention, it is not restricted to such a case, For example, an outer pipe | tube 11 may be embedded at a depth of about 100 to 400 m, or may be embedded at a depth of 600 to 1000 m. In addition, the geothermal recovery apparatus according to the present invention is typically applied to a circulation type geothermal power generation system as shown in FIG. 6, but is not limited thereto, and is used for other purposes such as a house. Of course, the present invention can be applied to other air conditioning systems.

11 Outer tube 11a Outer tube bottom 11aa Top surface 11b Outer tube upper end side opening 11b Outer tube inner wall surface 11c Outer tube bottom area 12, 13, 14 U-shaped inner tubes 12a, 12b, 13a, 13b, 14a , 14b U-shaped inner tube side tubes 12aa, 12ba, 13aa, 13ba, 14aa, 14ba Outer wall surface 12ab of the side tube in the U-shaped inner tube, 12bb Upper end side openings 12c, 13c of the U-shaped inner tube, 14c U-shaped inner pipe bottom 13, 14-shaped inner pipe 16 Evaporator 17 Power generation turbine 17a Generator 18 Condenser 19 Circulation pump 19a Water storage tank

Claims (4)

  An outer pipe through which geothermal heat is conducted in the underground and having a closed lower portion including at least a bottom, and three or more U-shaped inner pipes arranged in the outer pipe, Each of the three or more U-shaped inner tubes is configured so that the fluid circulates between its own interior and the load equipment on the ground so that the heat exchanges with the geothermal heat. A geothermal recovery device with three or more U-shaped inner tubes.   Each of the three or more U-shaped inner pipes is arranged such that the outer side surfaces thereof are close to or abut on the inner wall surface of the outer pipe and the bottom parts thereof are located at or near the bottom part of the outer pipe. The geothermal recovery apparatus provided with three or more U-shaped inner pipes according to claim 1, wherein   The three or more U-shaped inner pipes are arranged in the outer pipe while being displaced from each other in the direction of gravity and intersecting each other in the horizontal direction in the outer pipe. A geothermal recovery device with a U-shaped inner tube. The three or more U-characters according to claim 1, 2 or 3, wherein a gap between the outer tube and the three or more U-shaped inner tubes is filled with a material having good thermal conductivity. Geothermal recovery device with an inner pipe.

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