JP2011214798A - Underground heat exchanger using temporary underground continuous wall and method of constructing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underground heat exchanger using a temporary underground continuous wall capable of eliminating the necessity of excavation for embedding heat exchange piping and usable from an initial stage of a construction period.SOLUTION: In the underground heat exchanger 1, the heat exchange piping 12 is embedded in the ground and a heating medium is made to flow in the heat exchange piping 12 to exchange heat. The heat exchange piping 12 is arranged along core materials 112 within the temporary underground continuous wall 11, and is covered with protective materials 13.

Description

  The present invention relates to a geothermal heat exchanger for utilizing geothermal heat for a heat pump and a construction method thereof.

There is known a geothermal heat utilization system that uses geothermal heat, which has a high temperature stability compared to the outside air, for a heat pump for air conditioning or melting snow.
This system embeds heat exchanging pipes in the ground to form underground heat exchangers and distributes a heat medium such as water in the pipes to cool the underground heat, which is cooler than the outside air during cooling in summer. As a heat source, geothermal heat having a temperature higher than the outside air is used as a heat source during heating in winter.
In recent years, in order to reduce ground excavation costs when burying heat exchange pipes underground, heat exchange pipes are placed inside cast-in-place concrete piles that are the foundation piles of buildings. The method is adopted.

JP 2006-10133 A

However, the geothermal heat utilization system that uses the foundation pile as the underground heat exchanger has the following problems.
(1) Since the foundation pile is made of concrete with low permeability, the heat exchange efficiency between the heat medium in the heat exchange pipe arranged inside the foundation pile and the ground outside the foundation pile is low.
(2) Since there is a gap between the foundation piles, the length of the piping on the ground part becomes long, and the heat exchange efficiency as a system is lowered.
(3) Since the foundation pile is an underground heat exchanger, the system cannot be used during the construction period until the foundation pile is constructed.

  The present invention does not require excavation for burying heat exchange pipes, and can be used from the beginning of a construction period, and an underground heat exchanger using a temporary underground wall and its construction method The purpose is to provide.

The first invention of the present application made to achieve the above object is an underground heat exchanger in which a heat exchange pipe is arranged in the ground and a heat medium is circulated through the heat exchange pipe to exchange heat. The underground heat exchanger is characterized in that the heat exchanging pipe is arranged along a core material inside the temporary underground connecting wall, and the heat exchanging pipe is surrounded by a protective material.
According to a second aspect of the present invention, in the underground heat exchanger according to the first aspect, the underground heat exchanger is characterized in that the heat exchanging pipe is disposed on a natural mountain side inside the temporary underground connecting wall. provide.
3rd invention of this application is the construction method of the underground heat exchanger of 1st invention or 2nd invention, Comprising: The said heat exchange piping is arrange | positioned along the said core material before erection, and the said protective material The heat exchanger pipe is arranged inside the temporary underground wall by laying the core material that is surrounded by the heat exchanger pipe, and constructs the underground heat exchanger. Provide a method.
4th invention of this application is the construction method of the underground heat exchanger of 1st invention or 2nd invention, Comprising: The said protective material is arrange | positioned along the length direction of the said core material before erection, The said The core material on which the protective material is arranged is built and disposed inside the temporary underground connecting wall, the heat exchange pipe is inserted into a space surrounded by the protective material, and the heat exchange pipe is installed in the temporary construction. Provided is a method for constructing an underground heat exchanger, characterized in that the underground heat exchanger is disposed inside an underground wall.

The present invention can obtain at least one of the following effects by means for solving the above-described problems.
<1> The temporary underground underground wall in which the heat exchanging pipe is arranged is made of highly water-permeable soil cement, so that it can be an underground heat exchanger with high heat exchange efficiency.
<2> Since the heat exchanging pipes are arranged along the core material arranged side by side in the temporary underground connecting walls, the pipe length of the ground part can be shortened, and the heat exchanging efficiency as the system is hardly lowered.
<3> Excavation work for burying heat exchanging pipes is not necessary because it is arranged inside the temporary underground wall that is constructed for water retaining and earth retaining.
<4> Since the core material of the temporary underground underground connection wall is made of a steel material having a high thermal conductivity, the underground heat exchanger having a high heat exchange efficiency can be obtained.
<5> Since the heat exchanging pipe is arranged in advance on the core material before being built, the heat exchanging pipe can be arranged in the ground simultaneously with the construction of the core material.
<6> Since the heat exchange pipe arranged along the core material is protected by a protective material, it is not damaged or broken by gravel or the like in the soil cement during installation.
<7> Since the protection material is pre-arranged on the core material, the space for heat exchange piping is secured by the protection material, and the heat exchange piping is easily inserted after the core material is installed. Can be arranged.
<8> Temporary ground connection walls are constructed at the initial stage of the construction period, and can be used from the initial construction stage.

Explanatory drawing of the underground heat exchanger concerning this invention Sectional drawing of the underground heat exchanger concerning this invention Explanatory drawing of arrangement of heat exchange piping Illustration of protective material Explanatory drawing with protective material attached to the entire length of the core material Explanatory drawing of the ground heat utilization system using the ground heat exchanger of the present invention Explanatory drawing of construction method 2 Explanatory drawing of construction method 3

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[1] Configuration of the Present Invention FIG. 1 is an explanatory diagram of a ground heat exchanger according to the present invention.
The underground heat exchanger 1 of the present invention is configured by disposing a heat exchange pipe 12 in a temporary underground connecting wall 11. The heat exchange pipe 12 is surrounded by a protective material 13.
Hereinafter, each component of the underground heat exchanger 1 of this invention is explained in full detail.

<1> Temporary underground connecting wall The temporary underground connecting wall 11 is a wall constructed in the ground at the site, and is conventionally used as a water blocking wall or earth retaining wall.
The temporary underground connecting wall 11 is generally agitated and kneaded by injecting cement milk while excavating the ground using a multiple / multi-shaft drilling device having three or five augers. Thus, the wall body of the soil cement 111 is formed and hardened. (Figure 2)

<2> Core Material The core material 112 is for increasing the rigidity of the temporary underground wall 11 and is disposed inside the soil cement 111.
The core material 112 is a steel member such as an H shape.

<3> Heat Exchange Pipe The heat exchange pipe 12 is arranged in the temporary ground connection wall 11 and a heat medium such as water is circulated inside the temporary ground connection wall 11, thereby temporarily installing the temporary ground. Heat exchange is performed with the ground around the middle continuous wall 11.
The heat exchange pipe 12 is made of polyethylene and has flexibility.
The heat exchange pipe 12 is bent into a U shape to form an end 121, and the forward pipe 122 and the return pipe 123 are configured as a pair. (Figure 1)

<4> Arrangement of Heat Exchange Pipe The heat exchange pipe 12 is arranged along the length direction of the core material 112.
In the heat exchange pipe 12, an end 121 on the side bent in a U shape is arranged at the bottom of the core material 112.
The heat exchange pipe 12 is disposed inside the temporary underground wall 11 and on the natural mountain side.
The heat exchange pipe 12 may be disposed along the ground 112 side flange 112a of the core material 112, or may be disposed on the ground 112 side of the web 112b. (Figure 3)

<5> Protective Material The protective material 13 surrounds and protects the heat exchange pipe 12.
The protective material 13 is composed of a shape material, a bending material, a pipe material, and the like.
The protective material 13 surrounds the heat exchange pipe 12 (FIGS. 1, 3, and 4 b), but may be enclosed together with the core material 112. (Fig. 4a)
The lower end of the protective material 13 protects the end portion 121 by an inclined plate 131 that is arranged to be inclined with respect to the core material 112. (Fig. 5)

[2] Geothermal utilization system Next, a geothermal utilization system using the underground heat exchanger according to the present invention will be described.

<1> System Configuration The geothermal heat utilization system using the underground heat exchanger 1 is configured to connect the forward pipe 122 and the return pipe 123 of the heat exchange pipe 12 at the upper end of the temporary underground connecting wall 11 to the feed pipe 2. In addition, the heat pump 4 for air conditioning is connected to the air conditioning heat pump 4 through the return pipe 3 and the heat medium 5 is circulated therein, whereby the underground heat is used in the heat pump 4 for air conditioning. (Fig. 6)

<2> Use of Temporary Ground Connection Wall The underground heat exchanger 1 uses the temporary underground connection wall 11.
The temporary underground underground wall 11 is formed by curing the soil cement 111. Since the soil cement 111 has high water permeability, the underground heat exchanger 1 having high heat exchange efficiency can be obtained.

Moreover, the underground heat exchanger 1 arrange | positions the heat exchange piping 12 along the core material 112 inside the temporary underground underground connection wall 11.
Since the core material 112 consists of steel materials with high heat conductivity, it can be set as the underground heat exchanger 1 with high heat exchange efficiency.

In addition, the temporary underground connecting wall 11 is used as a water blocking wall or earth retaining wall, and is constructed at the time of underground work accompanying building work such as a building, that is, at the initial stage of the work period.
For this reason, the geothermal heat utilization system using the underground heat exchanger 1 can be used from the stage of construction work at the beginning of the construction period.

In addition, since the temporary underground connecting wall 11 is constructed using a multiple / multi-axis type drilling device having three or five augers, a plurality of core members can be formed by a single drilling operation. A temporary underground connecting wall 11 having 112 can be constructed.
For this reason, a plurality of heat exchange pipes 12 can be arranged by a single drilling operation, and the construction efficiency is good.

<3> Arrangement of Heat Exchange Pipe The underground heat exchanger 1 arranges the heat exchange pipe 12 along the core material 112 inside the temporary underground connecting wall 11, but the core material 112 is a temporary ground. A plurality of them are arranged in parallel in the middle continuous wall 11.
Since the plurality of heat exchange pipes 12 are arranged in parallel, the pipe lengths of the feed pipe 2, the return pipe 3, and other ground portions can be shortened, and the heat exchange efficiency as a geothermal heat utilization system is hardly lowered.
Moreover, since the core material 112 which arrange | positions the heat exchange piping 12 can be selected, the space | interval and the number of the heat exchange piping 12 with high heat efficiency can be selected, and the underground heat exchanger 1 can be constructed | assembled.

Moreover, since the temporary underground connecting wall 11 is constructed by using a multiple / multi-axis drilling device having three or five augers, only a part of the continuous temporary underground connecting wall 11 is provided. It can also be built deeper.
For this reason, since the length of the heat exchange pipe 12 can also be selected as appropriate, the underground heat exchanger 1 with high thermal efficiency can be constructed.

In addition, the heat exchange pipe 12 is arranged on the natural mountain side in the temporary underground connecting wall 11.
For this reason, even when the temporary underground connecting wall 11 is used as a retaining wall, the heat exchange pipe 12 is provided on the side in contact with the ground, so that the underground heat can be used efficiently.

[3] Construction method of underground heat exchanger Next, the construction method of the underground heat exchanger according to the present invention will be described.

[Construction method 1]
<1> Arrangement of Heat Exchange Pipe and Protective Material to Core Material In constructing the temporary underground wall 11, the heat exchange pipe 12 is arranged along the core material 112 before the core material 112 is built. And surrounded by the protective material 13.
Since the core material 112 can be laid on the ground, the heat exchange pipe 12 and the protective material 13 can be easily arranged.

<2> Cutting / Kneading The ground and cement milk are stirred and kneaded using a hole-drilling device to form a wall of the soil cement 111.

<3> Construction of the core material Before the soil cement 111 is hardened, the core material 112 on which the heat exchange pipe 12 is arranged is built.
Since the heat exchange pipe 12 is buried at the same time as the core material 112 is built, which is an essential work in the construction of the temporary underground connecting wall 11, the work of burying the heat exchange pipe 12 becomes unnecessary.
The heat exchange pipe 12 is surrounded and protected by a protective material 13. (Fig. 5)
By configuring in this way, it is possible to prevent the heat exchange pipe 12 from being damaged or broken by the obstacle 6 such as gravel during the erection.
Further, since the inclined plate 131 is disposed below the protective material 13, the soil cement 111 and the obstacle 6 are pushed out by the inclined plate 131 in the opposite direction to the core material 112, and thus the core material provided with the protective material 13. 112 can be built stably.

<4> Construction of underground heat exchanger When the soil cement 111 is hardened, an underground heat exchanger using the temporary underground underground wall 11 is obtained.
The feed pipe 2 and the return pipe 3 connected at one end to the heat pump 4 for air conditioning are connected to the heat exchanging pipe 12 of the temporary underground connecting wall 11, and the heat medium 5 is circulated to use the underground heat. A ground heat utilization system.

[Construction method 2]
In the construction method 1, the heat exchange pipe 12 is arranged along the core material 112 before being built and surrounded by the protective material 13, but only the protective material 13 is arranged on the core material 112 before being built. The heat exchange pipe 12 may be arranged along the core material 112 after the core material 112 is built. (Fig. 7)

Since the protective material 13 is disposed on the core material 112, a space S surrounded by the protective material 13 is formed in the temporary underground connecting wall 11 along the core material 112 in the placed state.
Since this space S is surrounded and formed by the protective material 13, there is no obstacle 6 such as gravel inside.
By inserting the heat exchange pipe 12 into the space S from the upper part 121 from above, the heat exchange pipe 12 can be easily placed in the ground.
In addition, it is possible to cope with the rearrangement of the work process in accordance with the progress of the site by making the process of laying the core material 112 and the process of arranging the heat exchange pipe 12 as separate processes.

[Construction method 3]
In the construction method 2 described above, when the core material 112 is constructed by building up the steel material, the protective material 13 is divided at the construction position of the core material 112, and after the core material 112 is built up, the protective material 13 is bolted. Connect them together to form one unit. (Fig. 8)

When the core material 112 is constructed by continuation of steel, the lower core material 112a and the protective material 13a are placed in advance so that the upper portion is exposed from the ground with a predetermined height. (Fig. 8a)
And the upper core material 112b of the state lifted with the crane etc. is arrange | positioned above the core material 112a. A protective material 13b is disposed on the core material 112b.
And after connecting core material 112a and 112b (Drawing 8b), protection material connecting tool 132 and protection materials 13a and 13b are connected, and protection material 13 is united. (Fig. 8c)
Since the protective material 13 is divided at the position where the core material 112 is connected and integrated after the connection, it is not necessary to connect the core material 112 over the entire length in advance on the ground, and it is possible to cope with a narrow site.

DESCRIPTION OF SYMBOLS 1 Ground heat exchanger 11 Temporary underground connecting wall 111 Soil cement 112 Core material 12 Heat exchange piping 121 End 122 Outward piping 123 Return piping 13 Protective material 131 Inclined plate 132 Protective material connector 2 Feeding pipe 3 Return pipe 4 Heat pump 5 for air conditioning

Claims (4)

A ground heat exchanger that arranges heat exchanging pipes in the ground and exchanges heat by circulating a heat medium in the heat exchanging pipes,
The heat exchange pipe is arranged along the core material inside the temporary underground wall.
An underground heat exchanger characterized in that the heat exchange pipe is surrounded by a protective material. The underground heat exchanger according to claim 1,
The heat exchanging pipe is arranged on a natural mountain side inside the temporary ground wall.
Underground heat exchanger. A construction method of the underground heat exchanger according to claim 1 or 2,
The heat exchange pipe is arranged along the core material before being built and surrounded by the protective material,
By laying the core material on which the heat exchange pipe is arranged, the heat exchange pipe is arranged inside the temporary ground wall.
Construction method of underground heat exchanger. A construction method of the underground heat exchanger according to claim 1 or 2,
The protective material is disposed along the length direction of the core material before being built,
The core material in which the protective material is arranged is built and arranged inside the temporary ground wall.
The heat exchange pipe is inserted into a space surrounded by the protective material, and the heat exchange pipe is disposed inside the temporary ground wall.
Construction method of underground heat exchanger.

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