JP2012097984A - Cast-in-place concrete pile with steel pipe for extracting geothermal heat - Google Patents

Abstract

In a cast-in-place concrete pile, underground heat can be efficiently transmitted to a heat medium circulating in a heat exchange pipe disposed in the pile, and underground heat can be efficiently utilized at low cost. Provide a way to do it.
In a cast-in-place concrete pile 11 provided with a heat exchange pipe 2 for circulating a heat transfer medium for underground heat exchange in the depth direction in the pile, a thermal conductivity is partially applied to the outer periphery 11a of the pile. Is installed, and the entire outer peripheral surface of the steel pipe 1 is brought into contact with the ground. By disposing the heat exchange pipe 2 so as to be in contact with the inner surface of the steel pipe 1, the underground heat can be efficiently transmitted to the heat medium circulating in the heat exchange pipe 2. Moreover, if the steel pipe 1 is installed in the pile outer peripheral part 11a which hits the depth of the specific formation (for example, the water permeable layer 22) which can collect heat of underground heat efficiently, it will be efficient and economical.
[Selection] Figure 1

Description

  The present invention relates to a cast-in-place concrete pile provided with a steel pipe having a high thermal conductivity in order to efficiently use underground heat.

In recent years, attention has been focused on geothermal utilization technology that is effective in reducing CO ₂ that is a cause of global warming and mitigating the heat island phenomenon. This technology pays attention to the fact that the temperature of the ground is little changed throughout the year, and uses thermal energy obtained from the temperature difference between the ground and the ground, and is used for air conditioning in buildings.

  There are two methods of using geothermal heat: the underground heat exchange type and the groundwater use type, both of which require a well for collecting ground heat, but the cost of digging this well is high. This is a factor that hinders the spread of medium heat utilization technology. For this reason, the method of using the foundation pile of a building as a well has been devised, and a foundation pile use type in which a heat exchange pipe is inserted into the foundation pile to collect ground heat has been attracting attention.

  Pile types of building foundation piles include precast concrete piles, steel pipe piles and cast-in-place concrete piles, and ground heat utilization technology has been devised for each pile type. In cast-in-place concrete piles, for example, a heat exchange pipe made of a resin tube or the like is installed in a reinforcing steel cage, and a heat medium such as water is circulated in the heat exchange pipe to perform underground heat exchange, so-called underground heat exchange. A mold is used.

JP 2004-324913 A JP 2004-332330 A

  Conventionally, there is a method of installing a heat exchange pipe (resin tube etc.) to circulate the heat medium in the cast-in-place concrete pile along the rebar cage, but usually the outer edge of the rebar cage is at least 10cm from the ground Since it is constructed separately, the distance from the ground to the heat exchange pipe is also 10 cm or more, and there is a problem that the heat conduction is poor and the underground heat cannot be effectively utilized.

  In Patent Document 1, in a cast-in-place concrete pile, a heat exchange pipe formed in a spiral shape is disposed inside a reinforcing bar and / or a steel pipe. In this case, steel pipe and concrete are interposed between the ground and the heat exchange pipe, and underground heat is transmitted through them. However, in Patent Document 1, which is considered to be at least 10 cm or more away from the ground to the heat exchange pipe as described above, the underground heat is not effectively utilized because the thermal conductivity of concrete is low.

  Further, in Patent Document 2, in a cast-in-place concrete pile, a heat exchange pipe is disposed in the gap between the design pile diameter of the foundation pile and the excavation hole, and is attached to a spacer for preventing eccentricity installed on the outer periphery of the reinforcing bar cage. Supporting configurations have been proposed. In this case, since the heat exchange pipe is arranged near the wall of the excavation hole, heat transfer with the underground heat can be performed more efficiently than the conventional heat exchange pipe arranged inside the pile. On the other hand, when the heat exchange pipe is inserted into the pile, it is conceivable that the heat exchange pipe contacts the borehole wall and is damaged.

  In addition, since there is a small gap between the excavation hole wall and the heat exchange pipe, the concrete filling performance in pile construction is poor, and the excavation hole wall and the concrete do not adhere to each other. There is also concern that the necessary peripheral frictional force will not be ensured.

  The present invention has been made to solve the above-described problems in the prior art, and in a cast-in-place concrete pile, a steel pipe having a high thermal conductivity is provided on a part of the outer peripheral portion of the pile to reduce underground heat. It aims at providing the cast-in-place concrete pile which has the function which can utilize geothermal heat efficiently by heat-collecting efficiently and arrange | positioning a heat exchange pipe on the inner surface of a steel pipe.

  The cast-in-place concrete pile according to claim 1, wherein the cast-in-place concrete pile is provided with a heat exchange pipe for circulating a heat medium for underground heat exchange in a depth direction in the pile. A steel pipe is installed in a part of the part, and the heat exchange pipe is arranged so as to contact the inner surface of the steel pipe.

  According to the present invention, by providing a steel pipe with high thermal conductivity in a part of the outer peripheral portion of the cast-in-place concrete pile, the entire outer peripheral surface of the steel pipe is brought into contact with the ground, and the underground heat possessed by the ground is heat-exchanged. It can be efficiently transmitted to the heat medium in the pipe via the steel pipe.

  In other words, by installing a steel pipe for underground heat collection on a part of the outer periphery of the cast-in-place concrete pile, and by providing a heat exchange pipe so as to be in contact with the inner surface of the steel pipe, first, the steel pipe that is in direct contact with the ground The underground heat is transmitted to the heat transfer medium, and then the underground heat is transmitted to the heat transfer medium flowing in the heat exchange pipe in contact with the steel pipe.

  In this way, because the heat exchange pipe is arranged on the inner surface of the steel pipe provided on a part of the outer peripheral part of the cast-in-place concrete pile, there is almost no space from the ground to the heat exchange pipe, and heat is generated inside the pile such as a rebar cage. Efficient heat transfer can be expected compared to the case where an exchange pipe is provided.

  In addition, since the heat exchange pipe is fixed on the ground in advance so as to be in contact with the inner surface of the steel pipe, there is no problem in concrete filling properties in concrete placement in pile construction as in Patent Document 2. The function as a pile is sufficiently secured.

  Furthermore, in the design of piles, steel pipes are provided on a part of the outer periphery of cast-in-place concrete piles, so-called cast-in-place steel pipe concrete piles. Since there is no need to provide, underground heat can be used at a lower cost. Cast-in-place concrete piles include cast-in-place steel pipe concrete piles.

  The cast-in-place concrete pile provided with the steel pipe for underground heat collection according to claim 2 is the cast-in-place concrete pile provided with the steel pipe according to claim 1, wherein the steel pipe is efficient in collecting ground heat. It is characterized by being installed at a position that includes a well-formed stratum with high thermal conductivity or a bedrock or a permeable layer with groundwater flow.

  According to the present invention, a specific formation capable of efficiently collecting geothermal heat, such as a formation having high thermal conductivity or a bedrock or a permeable layer having a groundwater flow, without using a steel pipe over the entire length of a cast-in-place concrete pile. By installing a steel pipe having a high thermal conductivity at a position including, a greater amount of underground heat can be taken into the pile than conventional concrete.

  The steel pipe should be installed in the depth direction at a part of the outer peripheral part of the cast-in-place concrete pile, and if the outer peripheral part of the pile is made into a steel pipe against the formation with high thermal conductivity, the underground heat Can be used efficiently and is economical.

  The cast-in-place concrete pile in the present invention is characterized in that a steel pipe for underground heat collection is arranged in a part of the outer peripheral portion of the pile to efficiently use the underground heat. It goes without saying that ground heat is also collected through the pile concrete in the heat exchange pipe disposed in the depth direction.

  The cast-in-place concrete pile provided with the steel pipe for underground heat collection according to claim 3 is the cast-in-place concrete pile provided with the steel pipe according to claim 1 or 2, wherein the heat exchange pipe is an inner surface of the steel pipe. In addition, one or a plurality of folds are arranged in the vertical direction or the horizontal direction, or are arranged in a spiral shape.

  If the heat exchange pipe provided on the inner surface of the steel pipe is arranged vertically, horizontally, or spirally to increase the contact area of the heat exchange pipe that contacts the inner surface of the steel pipe, the underground heat captured in the pile Can be more transferred to the heat medium in the heat exchange pipe.

  According to the present invention, in the cast-in-place concrete pile provided with the steel pipe according to claim 1 and claim 2, by taking a large contact area of the heat exchange pipe in contact with the inner surface of the steel pipe, Can be more transferred to the heat medium in the heat exchange pipe.

  Since the present invention is configured as described above, the following effects can be obtained.

  By providing a steel pipe with high thermal conductivity on a part of the outer periphery of the cast-in-place concrete pile, collecting ground heat efficiently, and arranging one or more heat exchange pipes so as to contact the inner surface of the steel pipe, The underground heat can be efficiently transmitted to the heat medium circulating in the heat exchange pipe.

  In addition, if steel pipes are installed in a specific position, such as a geological layer with high thermal conductivity that can efficiently collect ground heat in the depth direction of cast-in-place concrete piles, or a permeable layer with bedrock or groundwater flow, It is possible to efficiently use geothermal heat at a low cost.

It is the front view which showed notionally one Embodiment of the cast-in-place concrete pile which provided the steel pipe for underground heat collection which concerns on this invention. It is sectional drawing of embodiment of FIG. 1, (a) shows the AA cross section, (b) shows the BB cross section. It is the perspective view which showed notionally the inside of the steel pipe of embodiment of FIG. In a cast-in-place concrete pile provided with a steel pipe for underground heat collection according to the present invention, it is a perspective view in the case where a plurality of heat exchange pipes are folded back in the vertical direction inside the steel pipe.

  Hereinafter, the present invention will be described with reference to the accompanying drawings. In addition, this invention is not limited to embodiment shown below.

  FIG. 1 is a front view showing an embodiment of a cast-in-place concrete pile 11 provided with a steel pipe 1 according to the present invention, FIG. 2 (a) is a cross-sectional view of AA, and FIG. It is -B sectional drawing. In FIG. 3, the arrangement position of the heat exchange pipe 2 inside the steel pipe 1 is shown in a perspective view.

  First, excavate the ground and provide pile holes. Since the heat exchange pipe 2 for circulating the heat medium is built at the same time as the rebar cage 12, it is connected to the rebar cage 12.

  The steel pipe 1 is connected to the reinforcing steel basket 12 so as to be installed on the pile outer peripheral portion 11a corresponding to the depth of a specific formation (for example, the water permeable layer 22) that can efficiently collect ground heat.

  Further, the outer diameter of the steel pipe 1 is generally the same as the pile diameter A of the cast-in-place concrete pile 11 and is generally easy to construct. However, when the steel pipe 1 is used at the top of the pile, the surface area of the steel pipe 1 is increased. If the contact area with the ground is widened, a large amount of underground heat can be taken in. Therefore, an outer diameter larger than the pile diameter A may be used.

  Examples of the method of connecting the steel pipe 1 and the rebar cage 12 include a method of fixing by welding using a steel material produced by bending a reinforcing bar or a flat steel, and a method of fixing by bolting via a steel material (illustrated). (Omitted) Any material or fixing method may be used as long as it does not come off from the reinforcing steel basket 12 and there is no problem in strength and durability.

  As shown in FIGS. 2A and 3, the heat exchange pipe 2 is located outside the reinforcing bar 12 in the range from the upper end of the pile to the height of the upper end of the steel pipe 1 and the range from the lower end of the steel pipe 1 to the tip of the pile. It fixes so that it may circumscribe to the hoop muscle arrange | positioned in (2), and it installs so that it may become parallel to the main muscle 13.

  Moreover, the range of the depth which installs the steel pipe 1 is arrange | positioned so that the heat exchange pipe 2 may contact the inner surface of the steel pipe 1, as shown in FIG.2 (b).

  In addition, the heat exchange pipe 2 does not necessarily need to be installed in the entire range over the entire length of the pile, and may be installed in an arbitrary range in order to effectively use the underground heat.

  For example, as shown in FIG. 1, when the steel pipe 1 is installed at an intermediate depth of the pile, the heat exchange pipe 2 may be installed from the upper end of the pile to the lower end of the steel pipe 1 or installed over the entire length of the pile. May be.

  If the heat exchange pipe 2 is installed over the entire length of the pile, the amount of heat collected will increase. However, if the thermal conductivity of the formation below the steel pipe 1 is small, the efficiency of the entire underground heat utilization may decrease. Conceivable.

  FIG. 4 is a perspective view of a cast-in-place concrete pile 11 provided with a steel pipe 1 for underground heat collection according to the present invention, in which a plurality of heat exchange pipes 2 are vertically folded inside the steel pipe 1. The figure is shown.

  By exchanging a plurality of heat exchange pipes 2 arranged inside the steel pipe 1 in the vertical direction within the range of the steel pipe 1, the surface area in contact with the inside of the steel pipe 1 is increased, and the underground taken into the pile via the steel pipe 1 More heat can be transferred to the heat medium in the heat exchange pipe 2.

  Although FIG. 4 shows a case where the heat exchange pipe 2 is folded back five times in the vertical direction, the number of turns is not limited as long as there is no problem in the arrangement position.

  3 and 4 show an embodiment in which the heat exchange pipe 2 is folded back in the vertical direction, it may be folded back horizontally on the inner surface of the steel pipe 1 or may be arranged in a spiral shape. .

  In order to fix the heat exchange pipe 2 to the inner surface of the steel pipe 1, for example, a plurality of ring-shaped metal fittings are passed through the heat exchange pipe 2 in advance before inserting the steel pipe 1 into the pile hole, The inner surface of the steel pipe 1 is fixed by welding or an adhesive, and the heat exchange pipe 2 is brought into close contact with the inner surface of the steel pipe 1. In addition, a metal pipe or the like can be connected to the tip of the heat exchange pipe 2 and can be fixed by welding to the inner surface of the steel pipe 1.

  In addition, the fixing method of the steel pipe 1 and the heat exchange pipe 2 may be any material or fixing method as long as there is no problem in terms of strength and durability, as in the connecting method of the steel pipe 1 and the rebar cage 12 described above. Absent.

  The heat exchange pipe 2 is made of resin or metal, so long as there is no problem in strength and durability, the material and type of the heat exchange pipe 2 are not limited. As long as the steel bars 1 are bound to the hoop bars 14 of the reinforcing bar 12 and the steel pipe 1 and the reinforcing bar 12 are connected as long as there is no problem in terms of strength and durability, the material and fixing method are not limited.

  In addition, as shown in FIG. 2A, if the heat exchange pipe 2 is fixed to the hoop bar 14 of the reinforcing bar 12 so as to circumscribe, the distance from the excavation hole wall 23 is a spacer 15 for preventing eccentricity. Therefore, when the heat exchange pipe 2 connected to the reinforcing bar 12 is inserted into the pile hole, the excavation hole wall 23 is not contacted, and the heat exchange pipe 2 is not damaged.

  In this way, the heat exchange pipe 2 fixed to the steel pipe 1 is filled with a heat medium such as water and circulated to transfer heat from the ground to the steel pipe 1 and from the steel pipe 1 to the heat medium in the heat exchange pipe 2. Can be done efficiently.

  After installing the steel pipe 1, the heat exchange pipe 2, and the rebar cage 12 in the pile hole, concrete is placed in the pile hole to complete the cast-in-place concrete pile 11 provided with the steel pipe.

1 ... steel pipe,
2 ... heat exchange pipe,
11 ... Cast-in-place concrete pile, 11a ... Pile outer periphery,
12 ... rebar basket,
13 ... Main muscle,
14 ... Hoop muscle,
15 ... Spacer
21 ... Geologic formation (impermeable layer, etc.)
22 ... Geologic formation (permeable layer, etc.)
23 ... Drilling hole wall,
A ... Pile diameter

The cast-in-place concrete pile according to claim 1, wherein the cast-in-place concrete pile is provided with a heat exchange pipe for circulating a heat medium for underground heat exchange in a depth direction in the pile. A steel pipe is installed at a position including a geothermal layer with high thermal conductivity or a rock layer or a permeable layer with a groundwater flow, which can efficiently collect a part of the geothermal heat in the depth direction of the section, and the heat exchange pipe Ri arranged to tear so as to contact the inner surface of the steel pipe, characterized in that through the steel pipe in direct contact with the ground, ground heat is transferred to the heat medium flowing through the heat exchanger pipe which is in contact with the steel pipe It is what.

According to the present invention, by providing a steel pipe with high thermal conductivity in a part of the depth direction of the outer peripheral part of the cast-in-place concrete pile, the entire outer peripheral surface of the steel pipe is brought into contact with the ground, and the ground has the ground. Heat can be efficiently transferred to the heat medium in the heat exchange pipe via the steel pipe.

That is, by installing a steel pipe for ground heat collection in a part of the depth direction of the outer periphery of the cast-in-place concrete pile, and by installing a heat exchange pipe so as to contact the inner surface of the steel pipe, The underground heat is transmitted to the steel pipe in contact with the steel pipe, and then the underground heat is transmitted to the heat medium flowing in the heat exchange pipe in contact with the steel pipe.

In this way, because the heat exchange pipe is arranged on the inner surface of the steel pipe provided in the depth direction part of the outer peripheral part of the cast-in-place concrete pile, there is almost no space from the ground to the heat exchange pipe, such as a rebar cage Efficient heat transfer can be expected compared to the case where a heat exchange pipe is arranged inside the pile.

Furthermore, in the design of the pile, in the so-called cast-in-place steel pipe concrete pile in which the steel pipe is provided in a part of the depth direction of the outer peripheral portion of the cast-in-place concrete pile, if a heat exchange pipe is disposed on the inner surface of the steel pipe, Since there is no need to provide a new steel pipe, geothermal heat can be used at a lower cost. Cast-in-place concrete piles include cast-in-place steel pipe concrete piles.

In addition, the cast-in-place concrete pile in the present invention is characterized by arranging a steel pipe for underground heat collection in a part of the depth direction of the outer peripheral portion of the pile, and efficiently using the underground heat, It goes without saying that ground heat is also collected through the concrete of the pile body in other heat exchange pipes arranged in the depth direction in the pile.

The cast-in-place concrete pile provided with the steel pipe for underground heat collection according to claim 2 is the cast-in-place concrete pile provided with the steel pipe according to claim 1 , wherein the heat exchange pipe is formed on the inner surface of the steel pipe. One or more folds are arranged in the vertical or horizontal direction, or are arranged in a spiral shape.

A steel pipe with high thermal conductivity is provided in part of the depth direction of the cast-in-place concrete pile to collect ground heat efficiently, and one or more heat exchange pipes are provided so as to contact the inner surface of the steel pipe By doing so, underground heat can be efficiently transmitted to the heat medium circulating in the heat exchange pipe.

Claims (3)

  In a cast-in-place concrete pile provided with a heat exchange pipe for circulating a heat medium for underground heat exchange in the depth direction in the pile, a steel pipe is installed on a part of the outer periphery of the concrete pile, and the heat A cast-in-place concrete pile provided with a steel pipe for underground heat collection, wherein an exchange pipe is disposed so as to be in contact with the inner surface of the steel pipe.   2. The underground according to claim 1, wherein the steel pipe is installed at a position including a geothermal layer with high thermal conductivity or a bedrock or a permeable layer with a groundwater flow, which can efficiently collect ground heat. Cast-in-place concrete pile with steel pipe for heat collection.   3. The heat exchange pipe according to claim 1, wherein the heat exchange pipe is arranged on the inner surface of the steel pipe by being folded one or more times in a vertical direction or a horizontal direction, or arranged in a spiral shape. Cast-in-place concrete piles with steel pipes for underground heat collection.

Images