JP7010751B2 - How to bury a geothermal heat exchanger - Google Patents

Description

The present invention relates to a method of burying a geothermal heat exchanger connected to a heat pump.

Conventionally, equipment that uses the heat energy possessed by groundwater flowing through a sandy soil layer in the ground as a heat source for a heat pump has been used. These facilities are used for air conditioning, hot water supply, snow melting, etc.

FIG. 8 is a diagram showing a conventional geothermal heat pump system 119. The geothermal heat pump system 119 includes a heat pump 111, a geothermal heat exchanger 121 and the like. The heat pump 111 is installed in the vicinity of the building 115 that utilizes heat. The geothermal heat exchanger 121 is installed in the ground 101 by drilling a vertical hole by boring.

The geothermal heat exchanger 121 is installed so as to reach the aquifer 109 through the cohesive soil layer 103, the aquifer 105, and the aquifer 107 of the ground 101, for example. In the geothermal heat pump system 119, a fluid serving as a heat medium is continuously circulated between the geothermal heat exchanger 121 and the heat pump 111, and the heat energy collected from the ground is used as the heat source of the heat pump 111. At this time, in particular, the aquifer 105 and the aquifer 109, which can efficiently exchange heat, have an underground heat utilization range of 117.

In addition, excavation shafts and connecting shafts are excavated from the ground surface to the water layer, and the inside of the water layer is bored horizontally from the excavation shaft to the connecting shaft to install heat sampling pipes and heat pipes. A method of collecting heat (see, for example, Patent Document 1), excavating a shaft for excavation from the ground surface to the groundwater layer, boring laterally from the excavation shaft, laying a pumping strainer pipe and an injection strainer pipe, and pumping strainer. A method has been proposed in which groundwater is pumped from a pipe, used as a heat source, and then circulated in an injection strainer pipe (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2000-179276 Japanese Unexamined Patent Publication No. 2004-270412

However, in the geothermal heat pump system 119 shown in FIG. 8, the effective length arranged in the underground heat utilization range 117 is limited with respect to the installation length of the geothermal heat exchanger 121. Therefore, in order to obtain the required effective length, it is necessary to increase the number of installed geothermal heat exchangers or lengthen the installation length, which causes a problem that the construction cost increases.

The method of drilling a boring hole horizontally to collect heat can solve the above-mentioned problems, but it is necessary to construct a shaft for boring. In addition, if the aquifer is not deposited horizontally, there is a possibility that the boring hole for installing the pipe cannot be drilled at a position suitable for heat collection.

The present invention has been made in view of the above-mentioned problems, and an object thereof is an geothermal heat exchanger that can easily install a heat collecting pipe at a position where heat can be efficiently collected from an aquifer. Is to provide a method of burying.

In order to achieve the above-mentioned object, the present invention is a method of burying a geothermal heat exchanger connected to a heat pump, in which a drilling rod is started from the ground, and the drilling rod is vibrated or drilled. A step of drilling a curved boring hole so as to include a buried route located in the geothermal layer of the ground by controlling the rotation and non-rotation of the drilling rod while hitting the tip bit of the rod. A step b of installing a heat collecting pipe in the buried route and pulling out the drilling rod by using the curved boring hole is provided, and the exploration provided in the tip bit in the step a is provided. This is a method for burying a geothermal heat exchanger, which comprises drilling a curved boring hole while exploring the position of the water zone and determining the burial route .

If the rotation and non-rotation of the drilling rod are controlled while vibrating the drilling rod or hitting the tip bit of the drilling rod, it is three-dimensional so as to include the buried route in the aquifer of the ground. It is possible to drill a curved boring hole. As a result, not only when the aquifer is deposited horizontally, but also when it is deposited with an inclination or when it is deposited so that the thickness changes, the position where heat can be efficiently collected from the aquifer. It is possible to easily install a pipe for heat collection by drilling a curved boring hole. The vibration component applied to the drilling rod in the present invention may be in the axial direction or may be in a plurality of directions. By adding vibration components in a plurality of directions, even when the ground is hard or the hardness of the ground changes, the drilling direction can be performed in the planned direction without blurring.

It is desirable that the buried route is spiral or meandering in a plan view.
As a result, the pipes can be densely arranged in the aquifer with a small number of holes to lengthen the effective length used for heat collection, and heat can be collected efficiently.

In the present invention, in the step a, the curved boring hole is drilled while searching the position of the aquifer by the exploration section provided at the tip bit to determine the buried route .
This makes it possible to drill curved boring holes while exploring the depth, thickness, slope and horizontal extent of the aquifer to determine the burial route. In addition, since it is not necessary to explore the ground and determine the burial route in advance, the construction period can be shortened.

The exploration unit has, for example, a water injection unit that injects water into the ground, a packer that closes the curved boring hole, and a pore water pressure gauge that detects the permeability of the ground.
By using the exploration unit having such a configuration, it is possible to explore the permeability of the ground in real time during drilling.

In the step b, it is desirable to install the heat sampling pipe in the buried route using a water flow.
If the water flow is jetted backward from the tip of the pipe, the pipe can be easily installed in the drilling rod arranged in the buried route.

In the step a, it is desirable to start the drilling rod from the periphery of the heat utilization facility.
As a result, it is possible to drill a curved boring hole without interfering between the boring machine installed on the ground and the heat utilization facility.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for burying a geothermal heat exchanger in which a pipe for heat collection can be easily installed at a position where heat can be efficiently collected from the aquifer.

The figure which shows the process of drilling a curved boring hole 21 Cross-sectional view of the vicinity of the tip bit 12 of the drilling rod 11 The figure which shows the state which installed the geothermal heat exchanger 39 The figure which shows the method of arranging the pipe 29 of the underground heat exchanger 39 in the curved boring hole 21 drilled in the burial route 15. Top view of pipe 29 in underground heat utilization range 17 Plan view of pipe 29a in underground heat utilization range 17a The figure which shows the example which set the buried route 15a in the aquifer 5a three-dimensionally. The figure which shows the conventional geothermal heat pump system 119.

Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a process of drilling a curved boring hole 21. FIG. 1A is a diagram showing a state in which a drilling rod 11 is started from the ground to the ground 1, and FIG. 1B is a diagram showing a state in which a curved boring hole 21 is drilled in the ground 1. FIG. 2 is a cross-sectional view of the vicinity of the tip bit 12 of the drilling rod 11. FIG. 2A is a diagram showing a state in which the ground 1 is drilled, and FIG. 2B is a diagram showing a state in which the permeability of the ground 1 is being explored.

As shown in FIG. 1, in the ground 1, for example, an aquifer 5 which is a sandy soil layer exists below the cohesive soil layer 3, a cohesive soil layer 7 is further below the aquifer layer 5, and the aquifer layer is further below. It is assumed that 9 exists. A heat utilization facility 19 exists on the ground 1. A boring machine 13 for driving the drilling rod 11 is installed on the ground 1 around the heat utilization facility 19.

As shown in FIG. 2, the drilling rod 11 is a tubular material, and the tip bit 12 is provided with a drilling direction determining member 20. The drilling rod 11 has great toughness. The drilling direction determining member 20 is attached so as to form a predetermined angle with respect to the axial direction of the drilling rod 11 (the direction of the arrow X shown in FIG. 2A). A transmitter (not shown) for position search is installed on the tip bit 12 of the drilling rod 11. Further, the boring machine 13 is integrated with a gyro insertion / pulling device (not shown).

The boring machine 13 can rotate the entire drilling rod 11 as shown by the arrow A. Further, the drilling rod 11 can be pushed out toward the tip as needed. The drilling rod 11 is configured such that vibration is applied in the axial direction by the boring machine 13, or the tip bit 12 is hit by a hammer (not shown) installed on the base end side of the tip bit 12. It shall be configured.

The drilling rod 11 travels straight by combining rotation with axial vibration to the drilling rod 11 or impact on the tip bit 12. Further, by stopping the rotation of the drilling rod 11 and applying axial vibration to the drilling rod 11 or hitting the tip bit 12 in a non-rotating state, drilling in the direction of the drilling direction determining member 20 is performed. A hole is made and the drilling direction can be bent in any direction. It is also possible to adjust the curvature of the drilled hole by adjusting the vibration or the method of applying the batter and the pushing force by increasing or decreasing the number of hits per unit time according to the condition of the ground to be excavated. ..

As shown in FIG. 2, the drilling rod 11 is provided with a search unit 22 at the tip bit 12. The exploration unit 22 can move the tip bit 12 of the drilling rod 11 in and out of the tip bit 12 by pulling it back in the direction of the arrow B shown in FIG. 2 (b). The exploration unit 22 has a water injection unit 28 that injects water into the ground 1, a packer 25 that closes the curved boring hole 21, and a pore water pressure gauge 23 that detects the permeability of the ground 1.

A water injection pipe 27 is installed inside the drilling rod 11, and water injection portions 28 are provided at a plurality of locations of the water injection pipe 27 in the vicinity of the tip bit 12 of the drilling rod 11. The packer 25 is a member that can be expanded and contracted, and is provided around the water injection pipe 27 behind the water injection unit 28. The pore water pressure gauge 23 is provided on the surface of the water injection pipe 27 in front of the packer 25.

As shown in FIG. 2A, the exploration unit 22 is located inside the drilling rod 11 when the ground 1 is drilled. At this time, the packer 25 contracts, and the water injection pipe 27 stops water injection. As shown in FIG. 2B, in the state of exploring the ground 1, the exploration section 22 is exposed from the tip of the drilling rod 11. At this time, the packer 25 is pressed against the hole wall of the curved boring hole 21, and the water injection pipe 27 injects water from each water injection portion 28 in the direction indicated by the arrow C.

In the steps shown in FIGS. 1 (a) and 1 (b), the drilling rod 11 is started from above the ground 1, and a boring machine 13 is used to apply axial vibration to the drilling rod 11 or to the tip bit 12. By controlling the rotation and non-rotation of the drilling rod 11 while applying an impact, the drilling rod 11 bends into the ground 1 to drill a boring hole 21. When starting the drilling rod 11, the position of the aquifer 5 of the ground 1 shown in FIG. 1A has not been grasped, and the burial route 15 has not been determined. The drilling rod 11 repeats the work of drilling the ground 1 by a predetermined distance and the work of exploring the position of the aquifer 5 by the exploration unit 22 to determine the buried route 15, and makes the curved boring hole 21. Drill a hole.

When determining the burial route 15, the drilling rod 11 drills the ground 1 by a predetermined distance in the state shown in FIG. 2A, and then temporarily interrupts the drilling. Next, as shown in FIG. 2B, the tip bit 12 is pulled back in the direction of the arrow B to inflate the packer 25 and close the bent boring hole 21. After that, water is injected from the water injection section 28 as shown by the arrow C, water pressure is applied to the closed curved boring hole 21 to allow water to permeate the ground 1, and the pore pressure in the soil is measured by the pore water pressure gauge 23. The water permeability of the ground 1 is detected, the depth, the layer thickness, the degree of inclination and the horizontal spread of the aquifer 5 are grasped, and the burial route 15 of the drilling rod 11 is determined. After the burial route 15 is determined, the packer 25 is contracted, the tip bit 12 of the drilling rod 11 is returned to the original position, drilling is restarted, and drilling is performed again at a predetermined distance.

The underground heat utilization range 17 is usually set in the site of the heat utilization facility 19. The burial route 15 is determined to pass through the aquifer 5 in the underground heat utilization range 17. The buried route 15 is determined to be meandering in a plan view, for example.

In the process shown in FIG. 1, the position of a transmitter (not shown) installed on the tip bit 12 of the drilling rod 11 is searched for in real time from the ground portion during drilling of the ground 1 by the drilling rod 11. Further, by using a gyro insertion / pulling device (not shown) integrated with the boring machine 13 at an appropriate time during drilling, a gyroscope (not shown) is inserted and pulled in near the tip bit 12 of the drilling rod 11. , Measure the drilling locus of the drilling rod 11. If a problem occurs during drilling, pull back the drilling rod 11 to a few meters before, change the direction, and drill again.

FIG. 3 is a diagram showing a state in which the geothermal heat exchanger 39 is installed. FIG. 4 is a diagram showing a method of arranging the pipe 29 of the geothermal heat exchanger 39 in the curved boring hole 21 drilled in the buried route 15. 4 (a) is a diagram showing a state in which the exploration unit 22 is removed from the drilling rod 11, and FIG. 4 (b) is a diagram showing a state in which the pipe 29 is inserted into the drilling rod 11, FIG. 4 (c). Is a figure showing a state in which the drilling rod 11 is removed from the curved boring hole 21.

In the process shown in FIG. 3, the pipe 29 of the geothermal heat exchanger 39 is inserted and arranged from the ground in the curved boring hole 21 drilled in the buried route 15. The pipe 29 is, for example, a U tube. To arrange the pipe 29, first, as shown in FIG. 4A, the water injection pipe 27 is removed from the inside of the drilling rod 11 in the state shown in FIG. 2A. The water injection pipe 27 is pulled out from the ground side and removed.

Next, as shown in FIG. 4B, the water flow 35 is ejected rearward from the nozzle 33 provided at the tip of the pipe 29, so that the pipe 29 is inserted into the drilling rod 11 with the force of the water flow 35. do. After arranging the pipe 29 over the entire length of the buried route 15, the ejection of the water flow 35 is stopped, and the drilled rod 11 is removed from the curved boring hole 21 drilled in the buried route 15 as shown in FIG. 4 (c). .. At this time, if necessary, the space between the curved boring hole 21 and the pipe 29 is backfilled with sand.

In the geothermal heat pump system 37 shown in FIG. 3, after installing the pipe 29 of the geothermal heat exchanger 39 in the curved boring hole 21, the ground portion of the geothermal heat exchanger 39 is connected to the heat pump 31 installed on the ground. do. The geothermal heat pump system 37 circulates a medium such as an antifreeze liquid between the geothermal heat exchanger 39 and the heat pump 31, and heat is collected from the ground water in the underground heat utilization range 17 by the geothermal heat exchanger 39. , Used as a heat source for the heat pump 31.

As described above, according to the first embodiment, the rotation and non-rotation of the drilling rod are controlled while applying axial vibration to the drilling rod or hitting the tip bit of the drilling rod. The drilling rod 11 that can bend the drilling direction in any direction is started from the ground, and the drilling hole 21 is bent so as to include the buried route 15 in the aquifer 5 of the ground 1. As a result, the bending bore 21 can be drilled at a position where heat can be efficiently collected from the aquifer 5, and the heat collection pipe 29 can be installed. Further, by arranging the pipes 29 in the aquifer 5 in a meandering shape in a plan view, the effective length used for heat collection of the pipes 29 can be lengthened, and the number of holes can be reduced.

Further, the exploration section 22 is provided on the tip bit 12 of the drilling rod 11, and the exploration section 22 detects the permeability of the ground 1 in real time during drilling, whereby the depth, thickness, and inclination of the aquifer 5 are about. The curved boring hole 21 can be drilled while exploring the horizontal spread and determining the buried route 15 at the optimum position. Further, since it is not necessary to search the ground 1 in advance to determine the burial route 15, the construction period can be shortened.

In the first embodiment, the pipe 29 is easily installed in the drilling rod 11 arranged in the buried route 15 by injecting the water flow 35 rearward from the tip of the pipe 29 of the geothermal heat exchanger 39. can. Further, by starting the drilling rod 11 from the periphery of the heat utilization facility 19, the curved boring hole 21 can be drilled without the boring machine 13 installed on the ground and the heat utilization facility 19 interfering with each other.

Next, the second embodiment will be described. In the second embodiment, the points different from those in the first embodiment will be described, and the same configurations will be omitted by adding the same reference numerals in the drawings and the like.

In the second embodiment, the boring machine 13 shown in FIG. 1 applies vibrations in a plurality of directions to the drilling rod 11 shown in FIG. 2, and the entire drilling rod 11 is shown by an arrow A shown in FIG. Rotate to. The boring machine 13 may add a vibration component to the drilling rod 11 in the direction of the arrow Y shown in FIG. 2, or may apply vibration three-dimensionally to the drilling rod 11. Further, the boring machine 13 can push the drilling rod 11 toward the tip bit 12 as needed.

The drilling rod 11 travels straight by combining rotation and vibration. Further, by stopping the rotation of the drilling rod 11 and applying vibration in a non-rotating state, drilling is performed in the direction of the drilling direction determining member 20, and the drilling direction can be bent in any direction. .. It is also possible to adjust the curvature of the drilled hole by adjusting the method of applying vibration and the pushing force.

In the second embodiment, in the step shown in FIG. 1, the boring machine 13 is used to control the rotation and non-rotation of the drilling rod 11 while applying vibration to the drilling rod 11 from above the ground 1. The drilling rod 11 is started, and the drilling rod 11 bends into the ground 1 to drill a boring hole 21. In the second embodiment, after drilling the curved boring hole 21, the geothermal heat pump system 37 is constructed in the same procedure as in the first embodiment.

Also in the second embodiment, the same effect as that of the first embodiment can be obtained. In addition, since the vibration applied to the drilling rod 11 and the impact applied to the tip bit 12 in the first embodiment are axial impacts, the impact force is attenuated when the rod is long. Since the vibration of the drilling rod 11 of the second embodiment is applied in a plurality of directions and propagates without being dampened even when the rod is long, long-distance drilling is possible.

In the first embodiment, excavation of hard ground is difficult because forward excavation and excavation are performed by vibration or impact in the axial direction. However, in the second embodiment, the drilling rod 11 destroys the ground by vibration in a plurality of directions to drill a hole, and the pushing force in the axial direction from the rear hardly contributes to the drilling. Used only for advancing. Therefore, even if the ground is hard or concrete, it is possible to drill holes in the ground in front by vibration. Further, when drilling a hole in the vicinity of the boundary between the hard ground and the soft ground, in the first embodiment, the rod tip is on the soft ground side because the excavation is performed forward by vibration or impact in the axial direction. However, in the second embodiment, the drilling rod 11 destroys the ground in front of the drilling rod 11 by vibration in a plurality of directions to drill a hole, so that the traveling direction does not change. As described above, according to the second embodiment, even when the ground is hard or the hardness of the ground changes, the drilling direction is not deviated and the drilling is curved in the planned direction. It can be carried out. Further, by applying vibration in a plurality of directions, mud drainage is promoted and the hole wall of the curved boring hole 21 can be stabilized.

In the above-described embodiment, the drilling rod 11 is started from around the heat utilization facility 19 directly above the underground heat utilization range 17, and the drilling rod 11 is bent in a meandering shape to drill the boring hole 21 and the pipe 29 is installed. The starting position and drilling shape of the drilling rod 11 are not limited to this. If there is no structure or the like directly above the underground heat utilization range 17, a boring machine may be installed directly above the underground heat utilization range 17 to start the drilling rod 11. The drilling rod 11 can variably set the curvature of the curved boring hole, for example, between R10 and R20 by controlling rotation and non-rotation while applying vibrations in a plurality of directions as in the second embodiment. Therefore, it is possible to drill a hole in a shape other than the meandering shape.

5 and 6 are plan views of the pipe 29 in the underground heat utilization range 17. In the examples shown in FIGS. 5 and 6, the drilling rods 11 are started from the ground surface above the ground near the center of the underground heat utilization range 17, and four and eight are respectively directed from the center to the outside of the underground heat utilization range 17. The curved boring hole is drilled so as to be spiral in a plan view, and the pipe 29 is installed. As shown in FIGS. 5 and 6, even when the pipe 29 is arranged in a spiral shape, the effective length used for heat collection of the pipe 29 can be lengthened, and heat can be efficiently collected.

Further, in the above-described embodiment, the aquifer 5 is deposited in the horizontal direction to a substantially constant thickness, and the buried route 15 in the aquifer 5 is set substantially horizontally to install the pipe 29. An example is shown, but the burial route within the aquifer is not limited to horizontal. FIG. 7 is a diagram showing an example in which the buried route 15a in the aquifer 5a is set three-dimensionally. In the example shown in FIG. 7, the aquifer 5a of the ground 1 is deposited with an inclination and with a change in thickness.

Even in the ground 1a as shown in FIG. 7, the position of the aquifer 5a is searched by detecting the water permeability of the ground 1a by the exploration unit 22 every time the drilling rod 11 drills a predetermined distance. be able to. The drilling rod 11 bends in the ground 1a and drills a boring hole 21a while determining the burial route 15a so as to pass through the aquifer 5a in the underground heat utilization range 17.

In the geothermal heat pump system 37a shown in FIG. 7, the curved boring hole 21a is three-dimensionally drilled by the drilling rod 11 to arrange the pipe 29 of the geothermal heat exchanger 39. As a result, even when the aquifer 5a is deposited with an inclination or the thickness is changed, the boring hole 21a is bent at a position where heat can be efficiently collected, and a pipe for heat collection is made. 29 can be easily installed.

In the above-described embodiment, the exploration unit 22 searches for the position of the aquifer and determines the burial route while drilling a curved boring hole. However, the position of the aquifer is searched in advance for the burial route. After determining, the curved boring hole may be drilled. Further, in the above-described embodiment, the U tube is embedded as the pipe 29, but the method of burying the geothermal heat exchanger of the present invention can also be applied to the burying of the heat pipe.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modified examples or modified examples within the scope of the technical idea disclosed in the present application, and these also naturally belong to the technical scope of the present invention. Understood.

1, 1a, 101 ..... Ground 3,7,103,107 ......... Cohesive soil layer 5,5a, 9,105,109 ......... Water pressure layer 11 ......... Drilling rod 12 ......... Tip bit 13 ……… Boring machine 15, 15a ……… Buried route 17, 17a, 117 ……… Underground heat utilization range 19 ……… Heat utilization facility 20 ……… Drilling direction determining member 21, 21a ……… Bent boring Hole 22 ………… Exploration part 23 ………… Pore water pressure gauge 25 ………… Packer 27 ………… Water injection pipe 28 ………… Water injection part 29, 29a ………… Piping 31, 111 ………… Heat pump 33 ………… Nozzle 35 ……… Water flow 37, 37a, 119 ……… Geothermal heat pump system 39, 121 ……… Geothermal heat exchanger 115 ……… Building

Claims (5)

It is a method of burying a geothermal heat exchanger connected to a heat pump.
By starting the drilling rod from the ground and controlling the rotation and non-rotation of the drilling rod while vibrating the drilling rod or hitting the tip bit of the drilling rod, the band of the ground Step a of drilling a curved boring hole so as to include a buried route located in the water layer, and
In the step b of installing a heat collecting pipe in the buried route using the curved boring hole and pulling out the drilling rod,
Equipped with
In the step a, the geothermal heat exchange is characterized in that the curved boring hole is drilled while the position of the aquifer is searched by the exploration unit provided at the tip bit to determine the buried route. How to bury the vessel. The method for burying an underground heat exchanger according to claim 1, wherein the burial route is spiral or meandering in a plan view. The exploration unit has a water injection unit for injecting water into the ground, a packer for closing the curved boring hole, and a pore water pressure gauge for detecting the permeability of the ground, according to claim 1 or 2 . The method of burying the geothermal heat exchanger described. The method for burying a geothermal heat exchanger according to any one of claims 1 to 3 , wherein in the step b, the heat collecting pipe is installed in the burial route using a water flow. The method for burying an underground heat exchanger according to any one of claims 1 to 4 , wherein in the step a, the drilling rod is started from the periphery of the heat utilization facility.

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