JP2023112331A - Installation method of underground heat exchanger - Google Patents

Abstract

To install an underground heat exchanger with high accuracy in an efficient and inexpensive manner at, for example, large scale underground heat exchanger installation work.SOLUTION: An underground heat exchanger 5 having a continuous passage for causing a fluid to flow downward to the tip side relative to the ground surface side and upward to the ground surface side again. An installation method of the underground heat exchanger 5 includes: a heat exchanger pull-in step in which a cylindrical casing 4 which is inserted into the ground and pulled out by lifting means 3 is used to pull the underground heat exchanger 5 into the casing on the ground surface; a filler loading step in which a filler 6 is loaded into a gap between an inner periphery of the casing and the underground heat exchanger in the casing; an insertion step in which the casing 4 is inserted into the ground to a ground installation depth of the underground heat exchanger 5; and a pull-out step in which the casing 4 is pulled out and concurrently the underground heat exchanger 5 and the filler 6 in the casing are discharged from a lower end opening of the casing to be left in the ground.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a method of installing a subterranean heat exchanger suitable for utilizing subterranean heat.

The target underground heat exchanger is suitable for a vertical type that is installed vertically in the ground, among closed loops that indirectly utilize underground heat. Here, geothermal heat is the heat in the ground from the surface to a depth of about 200 m. It is colder and has the property of being warmer than the outside temperature in winter. Table 1 below lists installation methods, names, cross-sectional shapes, pipes, fillers (hereinafter referred to as fillers), etc. for the main vertical underground heat exchangers disclosed in Non-Patent Document 1. In the vertical type, the borehole method, in which several tens to hundreds of meters are drilled underground, is typical, but methods using structures such as foundation piles are also known.

(Table 1)

However, in the borehole method, a geothermal heat exchanger is inserted into a relatively small borehole formed by a boring machine or percussion drill, and the gap around the geothermal heat exchanger is backfilled with a filler such as silica sand. There must be. In the method of using structures such as foundation piles, since piles and continuous walls are essential along with heat exchangers, it is difficult to adopt when piles and continuous walls are not required due to the strength of the ground.

5 and 6 show other installation methods of the underground heat exchanger. FIG. 5 shows the installation method of Patent Document 1. FIG. This essential part is detachably attached to the tip of the casing 1 by connecting a tip shoe 5 made of a short tube having an excavating blade and a rotation receiving fitting 3 on the shoe side and a rotation transmitting fitting 4 on the casing side. In this state, a casing penetrating step of rotating and penetrating the casing 1 to a desired depth as shown in (a) to (c), and a picking step of connecting the extraction/radiation tube 11 to the tip shoe 5 through the inside of the casing 1 as shown in (d). A/radiating tube connecting process and a casing drawing process of pulling out the casing 1 with the tip shoe 5 and the collecting/radiating tube 11 left in the ground 19 as shown in (e).

FIG. 6 shows the installation method of Patent Document 2. FIG. As shown in (6A), the main part is a surface hole forming step of forming a surface hole 23a having a diameter larger than that of the drilled hole 23 in the ground surface layer, and a cylindrical hole in the surface hole 23a formed in the surface hole forming step. A hole wall protection material installation step of installing a curing pipe 28 which is a wall protection member, and a drilling hole forming step of forming a drilling hole 23 of a predetermined depth by a drilling pipe 24 penetrating the surface hole 23a as in (6B), A pipe member erecting step of erecting a U-shaped pipe 30, which is a pipe member as an underground heat exchanger, in the excavation hole 23 as shown in (6C), and an excavation pipe extraction step of pulling out the excavation pipe 24 from the excavation hole 23 as shown in (6D). and a filler filling step of filling the excavated hole 23 with the filler 40 until at least a portion of the curing pipe is filled with the curing pipe 28 left in the surface hole 23a.

JP 2011-133194 A JP 2015-98966 A

"Ground Heat Pump System" published by Ohmsha Co., Ltd., Hokkaido University Engineering Laboratory, October 20, 2020 (revised 2nd edition) pp. 52-79, especially the table on page 53

In the installation method of the underground heat exchanger shown in FIG. 5, since the tip shoe left in the ground is used, the cost increases, and the attachment and detachment operation of the tip shoe to the casing and the connection operation of the extraction/radiation pipe to the tip shoe are required. Therefore, the work becomes complicated. Also, it is explained that the gap formed around the intake/radiator tube when the casing is pulled out narrows with the lapse of time, but it is preferable to add a filler for treatment.

In the installation method of the underground heat exchanger of FIG. 6, curing pipes, which are pore wall protection members for preventing the surface layer from collapsing, and installation work thereof are required. It also requires the laborious task of filling the borehole or shaft formed by the withdrawal of the borehole tube or casing.

In view of the above background, an object of the present invention is to install a subterranean heat exchanger that can be installed efficiently and inexpensively with high accuracy, for example, in large-scale subterranean heat exchanger installation work. It is to provide a method. Other purposes will be made clear in the following description.

In order to achieve the above-mentioned object, the invention of claim 1, referring to FIGS. 1 to 4, provides a continuous passage where the fluid flows downward, i.e., the tip side, from the ground surface side, and then flows upward, i.e., the ground surface side. In the underground heat exchanger installation method, using a cylindrical casing (4 or 8) that is penetrated or withdrawn from the ground by a lifting means (3), the above-mentioned A heat exchanger hanging step for pulling in the underground heat exchanger (5 or 7), and a filling material (6) is put into the gap between the inner circumference of the casing and the underground heat exchanger in the casing. A filling material input step, a penetration step of penetrating the casing (4 or 8) into the ground to the underground installation depth of the underground heat exchanger (5 or 7), and pulling out the casing while inside the casing The underground heat exchanger (5 or 7) and the filler (6) are discharged from the lower end opening of the casing and left in the ground.

The above invention is more preferably embodied as specified in claims 2-6.
(A) When the underground heat exchanger is flexible, in the heat exchanger hanging step, the casing is held on the ground surface to provide a gap between the lower end of the casing and the ground surface, and the It is the structure which pulls an underground heat exchanger into the said casing (Claim 2).
(b) When the underground heat exchanger is non-flexible or rigid, in the heat exchanger hanging step, the underground heat exchanger is moved into the casing through an openable and closable opening formed around the casing. (Claim 3).

(c) In the underground heat exchanger suspending step, a winding drum provided on the upper part of the casing and on which a wire is wound so that the wire can be pulled out is used to suspend the underground heat exchanger from the wire of the winding drum. (Claim 4).
(d) In the filling material charging step, before starting the drawing step (specifically, before starting the penetration step, after starting the penetration step until finishing the penetration step) It is the structure thrown in in the said casing (Claim 5).

(E) In the penetration step, the casing is rotated or / and press-fitting or using a vibrating force to penetrate the casing, and in the withdrawal step, compressed air or / and liquid are injected to the upper side of the casing to cause the ground. It is configured to assist the discharge of the middle heat exchanger and the filler (Claim 6).

In the invention of claim 1, as a method of installing the underground heat exchanger, the essential members are only the underground heat exchanger and the filler, so the cost can be reduced compared to Patent Documents 1 and 2, and the installation state is underground. The medium heat exchanger is well covered with the filler, so the quality is also excellent. In addition, the construction machine used in this installation method can be a general pile driver or ground improvement machine, so if it is implemented together with ground improvement, indirect costs can be omitted or reduced.

In the invention of claim 2, when the underground heat exchanger is flexible, the casing is held on the ground surface in the heat exchanger hanging process, and a gap is provided between the lower end of the casing and the ground surface, and the ground is removed from the gap. The medium heat exchanger can be easily lifted into the casing using its flexibility. On the other hand, in the invention of claim 3, if the underground heat exchanger is non-flexible or rigid, the underground heat exchange is carried out through the openable and closable opening provided around the casing in the heat exchanger hanging process. It is also possible to pull the vessel into the casing.

In the invention of claim 4, in the underground heat exchanger suspending step, the winding drum provided at the top of the casing is used to efficiently insert the underground heat exchanger into the casing through the wire of the winding drum. can be drawn in.

In the invention of claim 5, in the filler charging step, the filler is charged into the casing before the penetration step is started or while the penetration step is performed, so it is difficult to cause insufficient filling of the filler or bias in the filling state. Become.

In the sixth aspect of the invention, in the penetration step, the casing is rotated and/or is penetrated using press-fitting or vibratory force. During the extraction process, compressed air and/or liquid is injected into the upper side of the casing to assist in the evacuation of the ground heat exchanger and packing material. These can be easily carried out by using ordinary pile drivers and soil improvement machines, and can efficiently carry out penetration and discharge work.

It is a schematic diagram which shows the ground improvement machine used for the installation method of the said underground heat exchanger, (a) shows the whole structure, (b) has shown the detailed structure of a casing. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the installation method of the underground heat exchanger of this invention form, (a) shows a heat exchanger hanging process, (b) shows a filler input process, (c) shows a penetration process. and (d) shows an underground leaving step. (a) and (b) are schematic diagrams showing before and after pulling the underground heat exchanger into the casing of the construction apparatus. 4(a) and 4(b) are schematic diagrams showing modifications of the casing of FIG. 3. FIG. FIG. 9 disclosed in Japanese Unexamined Patent Application Publication No. 2011-133194 of Patent Document 1 is shown. FIG. 6 disclosed in Japanese Unexamined Patent Application Publication No. 2015-98966 of Patent Document 2 is shown.

Hereinafter, embodiments to which the present invention is applied and modifications thereof will be described with reference to the drawings. In this explanation, a configuration example of a ground improvement machine for raising and lowering a casing, a method of installing a subterranean heat exchanger, and a modification of the casing will be described in this order. In addition, the drawings are simplified or the details are omitted, and the length of the underground heat exchanger is shorter than the actual size.

(Soil Improving Machine) A soil improving machine 1 shown in FIG. 1(a) is an example for supporting a cylindrical casing 4 which is a hollow tube so as to be able to move up and down and to rotate. This ground improvement machine 1 includes a base machine 10, a leader 2 erected movably via the base machine 10, and a casing 4 supported under an attachment 26, and moves up and down along the leader 2. a housing 27 coupled to the lower side of the attachment 26; an electric motor 28 provided on the housing 27 for rotating the casing 4; and a support plate 37 provided on the lower side of the housing 27 and supporting the winding drum 38. As it is pulled out, it is rotated forward or backward by the electric motor 28 or the like.

Here, the base machine 10 is a control room 12 in which the upper body is rotatably supported with respect to the caterpillar 11 side. It has a motor 14, an electric frame 15, and the like. The reader 2 is pivotally supported by a receiving member 16 and vertically supported by a three-point support stay 17 and the like. The reader 2 includes guide rods 20 provided on the front side of the reader (right side in the drawing) and extending vertically on both sides, a rack 21 provided between the guide rods 20 and extending vertically, and a lower rack. It has anti-vibration tools 29 and the like for anti-vibration of the casing provided on the side.

The lifting means 3 includes a pinion 24 that is incorporated in a box 22 that is moved up and down while being fitted to the guide rod 20 and that meshes with the rack 21 , and a hydraulic motor (not shown) that drives the pinion 24 . As the pinion 24 rotates, the attachment 26 and the casing 4 and the like connected to and supported by the attachment 26 are moved up and down as one unit. The upper end 4a side of the casing 4 is supported inside and below the attachment 26, and is operatively connected to a gear mechanism built in the housing 27, and the electric motor 28 held on the housing 27 is driven. and forward or reverse through the gear mechanism. A lower joint portion 30 is provided on the lower side of the housing 27 , and a support plate 37 is provided between the lower joint portion 30 and the lower flange portion 35 .

The casing 4 has an excavating edge 40 attached to the outer circumference of the lower end 4b. As can be inferred from FIG. 3, the underground heat exchanger 5 is a joint that connects the lower ends of a first pipe 5a through which a fluid such as a liquid flows downward and a second pipe 5b through which a fluid flows upward from the bottom. 5c is integrated. That is, the underground heat exchanger 5 is an example of a double U tube made of polyethylene, which is also listed in Table 1 above.

When the filler 6 is put into the hopper 25 from a bucket or the like, the filler 6 drops from the attachment 26 into the cylinder of the casing 4 by its own weight. As shown in FIG. 1B, the lower joint portion 30 is provided with an air valve 31 for opening and closing the inside of the joint portion, and an air supply nozzle 34 for supplying compressed air to pressurize the inside of the casing 4 . The air valve 31 comprises a valve body 32 mounted on the inner circumference of the lower joint portion 30 and a valve cover 33 pivotally supported on the valve body 32 . The valve cover 33 is normally in an open position hanging down by its own weight with respect to the valve main body 32, and when compressed air is injected from the air supply nozzle 34, the valve cover 33 is pressed by the air pressure to close the valve. However, the opening/closing mechanism of the air valve 31 may have a structure other than this. The air supply nozzle 34 is connected to a compressor on the ground surface side through a supply pipe so that compressed air of a required pressure can be injected when necessary. That is, the air supply nozzle 34 can switch the valve cover 33 to the closed state by the compressed air pressure to be injected, and easily discharge the filling material 6 and the underground heat exchanger 5 put into the casing 4 from the lower end 4b of the casing 4. do.

On the other hand, the support plate 37 holds a winding drum 38 on which a wire 39 is wound so as to be pulled out. A wire 39 pulled out from a winding drum 38 is introduced into the center of the cylinder of the casing 4 through a guide member 36 provided inside the lower flange portion 35, and a holder connected to the lead end of the wire 39. 45. The holder 45 is a member that detachably connects the upper end portion of the underground heat exchanger 5, and is changed according to the shape of the underground heat exchanger. Moreover, the holder 45 detachably supports two sets of the underground heat exchangers 5, that is, has holes or the like for detachably connecting the upper ends of the two sets of pipes 5a and 5b. Attachment and detachment of the pipes 5a and 5b can be performed by an operation unit on the ground surface side.

(Installation Method) Next, a method for installing the underground heat exchanger 5 in the ground using the soil improvement machine 1 will be described with reference to FIGS. 2 and 3. FIG. That is, in this installation method, there are a heat exchanger hanging step of drawing the underground heat exchanger 5 into the casing 4, a filler charging step of charging the filler 6 into the casing 4, and an underground heat exchanger 5 underground. A configuration in which a casing penetrating step of penetrating the casing 4 into the ground to the installation depth and an underground leaving step of discharging the underground heat exchanger 5 and the filler 6 from the casing 4 while pulling out the casing 4 and leaving them in the ground are sequentially performed. is.

I will elaborate. In the heat exchanger hoisting process, if the underground heat exchanger 5 is deformable or flexible, the casing 4 is lifted above the ground surface by the elevating means 3 as shown in FIG. Keep a certain distance. From this state, the holder 45 is pulled out from the lower end 4b of the casing through the wire 39 of the winding drum by manipulating the ground surface side. Then, the upper end portions of the first pipe 5 a and the second pipe 5 b that constitute the underground heat exchanger 5 are attached to the corresponding holes of the holder 45 . In this example, the wire 39 is wound up by the winding drum 38, so that two sets of underground heat exchangers are simultaneously inserted into the casing from the opening at the lower end of the casing as shown in FIGS. 2(a) and 3(b). be drawn in.

In the filler charging step, the filler 6 is charged from the hopper 5 into the casing 4, and the space or gap formed between the inner circumference of the casing 4 and the underground heat exchanger 5 is filled with the filler 6. make it This step is performed before the casing 4 is penetrated into the ground. In this example, since the casing 4 does not have a lid for opening and closing the lower end opening, the casing 4 is lowered to the ground surface to cover the lower end opening with the ground surface as shown in FIG. 2(b). Then, the filling material 6 is put into the casing 4 .

In the casing penetration step, the casing 4 is rotated forward by the electric motor 28 and the like, and lowered to the target depth by the lifting means 3 . In this case, the casing 4 may be penetrated by vibrating force such as a vibrating hammer.

In the underground leaving step, the underground heat exchanger 5 and the filling material 6 are pulled up to a predetermined height on the ground surface by the lifting means 3 while being discharged from the lower end opening of the casing 4 as shown in FIG. 2(d). In this extraction process, compressed air is injected from the air injection nozzle 34 to the upper side of the casing 4 (liquid may be injected from the injection nozzle 34) to assist the discharge of the underground heat exchanger 5 and the filler 6, That is, it is preferable that the underground heat exchanger 5 and the filler 6 are reliably discharged from the lower end opening of the casing 4 and left in the ground.

(Operation) In the underground heat exchanger installation method described above, first, the underground heat exchanger 5 is placed in the casing 4 suspended on the ground surface by the underground heat exchanger hanging step and the filling material charging step. It is possible to accurately perform the work of covering the surroundings of the base with the filling material 6. - 特許庁In addition, after the casing 4 is penetrated to a predetermined depth in the penetration process, the underground heat exchanger 5 and the filler 6 in the casing 4 are discharged into the ground as the casing 4 is pulled out in the extraction process, which makes construction easier and accuracy. It can be constructed well. In other words, in this underground heat exchanger installation method, the essential members are only the underground heat exchanger 5 and the filler 6, so the cost can be reduced compared to Patent Documents 1 and 2, and in the installed state Since the underground heat exchanger 5 is satisfactorily covered with the filler 6, the quality is excellent. Moreover, since the general ground improvement machine 1 can be used as the construction machine used in this installation method, indirect costs can be omitted or reduced by implementing the ground improvement together.

In addition, in this installation method, if the underground heat exchanger 5 is flexible as in the embodiment, the casing 4 is held on the ground surface in the heat exchanger hanging process, and the space between the casing lower end 4b and the ground surface is maintained. A gap is provided in the casing, and the underground heat exchanger can be easily lifted into the casing through the gap by utilizing its flexibility. In the underground heat exchanger suspension process, the winding drum 38 provided on the upper part of the casing 4 is used to efficiently load the underground heat exchanger 5 into the casing 4 through the wire 39 of the winding drum. can be drawn in. Furthermore, in the filling material charging process, since the filling material is charged into the casing before the casing penetration process is started, it is difficult for the filling material to be insufficiently filled or the filling state to be biased. However, the filling material charging step may be performed before starting the drawing step, and may be performed before starting the intruding step or before finishing the intruding step.

(Modification of underground heat exchanger) In this modification, if the underground heat exchanger 7 is non-flexible or rigid, the underground heat exchanger is moved from the lower end opening of the casing to the casing in the heat exchanger hanging process. Since it is difficult to pull it inside, one example of the countermeasure is schematically shown in FIG.

That is, in FIG. 4, the casing 8 is composed of halves 8A and 8B connected by a hinge 8a so as to be able to be opened and closed in the left-right direction. In the heat exchanger hanging process, the halves 8A and 8B are left and right separated with the hinge 8a as a fulcrum, and the underground heat exchanger 7 is lifted from the opening 8b formed therebetween by the holder 46 and the wire 39 while the halves are lifted. After the halves 8A and 8B are pulled inward, the halves 8A and 8B are kept closed by a band-like fastener 8c as shown in FIG. 4(b). The underground heat exchanger 7 is assumed to be the spiral tube shown in Table 1 above, and the first pipe 7a has a spiral shape and the second pipe 7b has a linear shape. It should be noted that the excavating blade and the like on the lower end side of the casing are omitted in FIG.

In this configuration, the lead-out end of the wire 39 is bifurcated 39 a and connected to the upper surface of the holder 46 . The holder 46 is a member that detachably connects the upper ends of the first pipe 7a and the second pipe 7b that constitute the underground heat exchanger 7, and detachably connects the upper ends of the pipes 7a and 7b. It has holes and the like. Attachment and detachment of each of the pipes 7a and 7b can be performed by an operation unit on the ground surface side.

It should be noted that the above embodiment examples and modifications do not limit the present invention in any way. The present invention only needs to include the technical elements specified in each claim, and the details can be variously changed or modified as necessary. Examples include single tube, double tube, and similar tube configurations for underground heat exchangers. Fillers include silica sand, pea gravel, cement, soil cement, and similar materials.

1 ・・・・・・・・Soil improvement machine 2 ・・・・・・・・ Leader 3 ・・・・・・・・ Elevating means 4 ・・・・・・・・ Casing (4a is the upper end, 4b is lower end)
5 ..... Underground heat exchanger (5a is the first pipe, 5b is the second pipe)
5c Joint 6 Filler 7 Underground heat exchanger (7a is the first pipe, 7b is the second pipe)
8 ..... Casing (8A, 8B are halves, 8a is hinge)
34 Air supply nozzle 38 Winding drum 39 Wire 40 Excavating blade 45 Holder 46......Holder

Claims (6)

In a method for installing a subterranean heat exchanger having a continuous passage through which the fluid flows downward, i.e., the tip side, from the ground surface side, and then flows upward, i.e., the ground surface side,
Using a cylindrical casing that is penetrated and withdrawn from the ground by lifting means,
A heat exchanger hanging step of pulling the underground heat exchanger into the casing on the ground surface;
A filler charging step of charging a filler into a gap formed between the inner periphery of the casing and the underground heat exchanger in the casing;
a penetration step of penetrating the casing into the ground to a depth of underground installation of the underground heat exchanger;
A subterranean heat exchanger characterized by passing through a pulling step of pulling out the casing and discharging the underground heat exchanger and the filler in the casing from the lower end opening of the casing and leaving them in the ground. Installation method. The underground heat exchanger is flexible, and in the heat exchanger hanging step, the casing is held on the ground surface to provide a gap between the lower end of the casing and the ground surface, and the underground heat exchange is performed through the gap. 2. The method of installing a subterranean heat exchanger according to claim 1, wherein the vessel is pulled into the casing from the opening at the lower end of the casing. The underground heat exchanger is a non-flexible or rigid body, and in the heat exchanger hanging step, the underground heat exchanger is pulled into the casing from an openable and closable opening formed around the casing. The installation method of the underground heat exchanger according to claim 1. In the underground heat exchanger suspending step, a winding drum provided on the upper part of the casing and winding a wire so that the wire can be pulled out is used to suspend the underground heat exchanger through the wire of the winding drum. The installation method of the underground heat exchanger according to any one of claims 1 to 3, wherein the underground heat exchanger is pulled into the casing. 5. The method of installing a subterranean heat exchanger according to claim 1, wherein in the filling material charging process, the filling material is charged into the casing before starting the drawing process. In the penetration step, the casing is rotated or / and press-fitting or using an exciting force to penetrate, and in the withdrawal step, compressed air or / and liquid are injected to the upper side of the casing to perform the underground heat exchange. 6. The method of installing an underground heat exchanger according to any one of claims 1 to 5, wherein the discharge of the vessel and the filling material is assisted.

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