JP2004278866A - Heat collection piping unit for underground heat exchange system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat collection piping unit for an underground heat exchange system capable of facilitating the inserting operation into a bored hole and decreasing the initial investment cost of the system which uses the underground heat by enlarging the heat exchange capacity of heat collection pipes and turning them into a unit system. <P>SOLUTION: The heat collection piping unit 1 is structured so that 10-m long pipes 3 made of titanium or stainless steel are threaded through flanges 2 in doughnut shape furnished with an even number of pipe holes 30 in the circumferential arrangement. Because the pipes 3 are connected at each flange 2, one end of each pipe 3 is protruded from the flange while the other end is positioned inside the flange 2. The heat collection piping unit 1 for the bottom with the pipe ends coupled together by a U-pipe is inserted into the bored hole, and the unit connection is made in compliance with the hole depth. An O-ring 33 is fitted on the pipe ends on the side protruding from the flange 2, and the pipes 3 are secured to the flange 2 using a sleeve 35 having a taper 34. The flanges 2 are fixed to each other by bolts 25. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention effectively utilizes a low-temperature heat source existing in a relatively shallow part of the ground at a depth of 10 m to 100 m underground, and efficiently uses underground heat to efficiently perform snow melting, heating, cooling, and the like. Tube unit for an underground heat exchange system.
[0002]
[Prior art]
In response to global warming, clean natural energy has been spotlighted as an alternative to fossil fuels.
The temperature below 10m below the ground is almost constant throughout the year, and the energy density is low, but it is a promising energy source.
[0003]
[Patent Document 1]
JP 2001-289533 A (claims, abstract, FIG. 1)
[0004]
As the underground heat exchange system, the following system is exemplified as shown in FIG.
(1) Double tube system.
(2) U tube method.
(3) WU tube method.
The double-pipe system consists of a double pipe consisting of an inner pipe and an outer pipe, and the circulating brine that has passed through the heat pump from the lower end of the inner pipe is discharged to the outer pipe and returned to the heat pump again through the outer pipe. It is a circulation method. A system in which the brine circulates from the outer pipe through the inner pipe is also possible.
[0005]
In the well method, the brine circulation path is the same as that of the double pipe method, but the outer pipe is larger than the inner pipe, and the brine passing through the outer pipe needs to be suctioned near the ground surface. From the point of view of the cyclic form of.
[0006]
The U-tube method is a system in which two high-density polyethylene pipes are connected by a U-pipe, attached to a weight, lowered into a drilled hole, filled with grout around the pipe, and fixed. Heat exchange through brine.
[0007]
The WU tube method is a method in which two sets of U-tubes are placed at right angles, lowered into a hole, filled with grout around the pipe and fixed, and heat is exchanged by passing brine through the WU tube. is there.
[0008]
[Problems to be solved by the invention]
In the geothermal heat exchange system, the cost of drilling accounts for a considerable proportion, so it is necessary to increase the heat extraction efficiency per drilling and to reduce the number of drillings. In addition, measures must be taken to prevent leakage of brine flowing down the heat collection tube, which is a medium for heat exchange, to ensure safety, and to further increase the efficiency of the heat collection tube to reduce the construction cost per hole. There is.
[0009]
The amount of heat exchange is proportional to the product of the amount of brine passing through the tube serving as the heat collection tube and the temperature difference between the inlet and the outlet of the tube. In order to increase the heat exchange efficiency, it is necessary to use a tube made of a material with high thermal conductivity, or to increase the surface area of the tube and the cross-sectional area to increase the heat exchange area. It is.
[0010]
The double tube method can maximize the amount of brine since the cross section through which the brine flows can be maximized within the same diameter hole as compared with the U tube method and the WU tube method. However, if the brine cross-section is the same as the converted cross-sectional area of the U-tube method or the WU-tube method, the amount of heat exchange is reduced because the surface area is small. Therefore, the amount of brine sent can be increased, but the heat exchange capacity is not so large.
In addition, in the double-pipe system, the filling pipe for the filler such as grout must be arranged outside the outer pipe, and if the outer pipe is not made smaller by the filler filling pipe, it can be inserted into the drilled hole. There is a problem that can not be.
[0011]
The U-tube method is made of a synthetic resin hose, so it has no seams, has high water-blocking properties, and can be easily installed in a drilled hole. In addition, since the thermal conductivity of the synthetic resin constituting the tube is small, the overall heat exchange rate is low.
[0012]
The WU tube method is excellent in water stopping performance and workability, like the U tube, and has a relatively high heat exchange efficiency because it has twice the surface area of the U tube.
However, the conventional method can achieve only about 10 to 30 W / m of the amount of heat collected, and the heat exchange efficiency is not sufficient. For this reason, the required heat quantity was secured by increasing the drilling depth or increasing the number of drilling holes, thereby causing an increase in initial investment cost.
The present invention seeks to increase the heat exchange capacity of the heat collection tube and to unitize the heat collection tube, thereby facilitating insertion work into the borehole and reducing the initial investment cost of a system using ground heat. Is what you do.
[0013]
[Means for Solving the Problems]
An even number of corrosion-resistant metal pipes are fixed at both ends with annular flanges provided with holes for pipes in the circumferential direction, and by connecting the pipes through the flanges, a larger number of heat sampling tubes than before Was inserted into the drilled hole to increase the heat collection.
In addition, an O-ring and an enlarged-diameter portion for accommodating the O-ring are used for pipe connection, thereby simplifying the connection work and increasing safety against liquid leakage.
[0014]
【Example】
Example 1
As shown in FIG. 1, the heat collecting tube unit 1 has a donut-shaped flange 2 having an even number of pipe holes 30 formed in the circumferential direction in FIG. It is a unit that passes through a pipe 3 of 10 to 10 m. Since the pipe 3 is connected at the flange 2, one end of the pipe 3 projects from the flange, and the other end is located inside the flange 2. After the heat collection tube unit 1 is inserted into the drilling hole, a grout injection pipe (not shown) is arranged to the drilling bottom using the hole 20 at the center of the flange 2 shown in FIG.
[0015]
As shown in FIG. 2, in the heat collecting tube unit installed at the bottom of the drilling hole, the ends of the pipes 3 facing each other are connected by a U-shaped tube 31, so that the brine circulates. Therefore, it is possible to arrange more pipes 3 than in the WU tube method in the drilled cross section, and it is possible to increase the amount of circulating brine and increase the heat exchange amount of the underground heat exchange system.
[0016]
FIG. 3 shows a plan view of the flange 2. The units are connected by bolts 25 with the flanges 2 in contact.
As shown in FIG. 4 and the details of the end of the pipe 3 in FIG. 5, a concave portion 32 is formed in the end of the pipe 3 protruding from the flange 2 and an O-ring 33 is inserted therein. On the rear side of the O-ring, a sleeve 35 having a taper 34 for fixing the pipe 3 to the flange is fitted into the pipe. An enlarged diameter portion 36 is formed at the end of the pipe of the unit on the other end of the connection so that an O-ring can be accommodated. After joining the pipes 3, bolts 25 are attached to the flanges 2 to fasten the units.
In the unlikely event that brine leaks, it must pass through different double joints, and a single watertight structure is formed by fastening with one bolt, so it is highly safe against liquid leakage .
Since the pipes 3 are connected in a watertight manner and the flanges 2 are fixed with bolts, the number of units can be increased or decreased to correspond to the depth of the drilled hole.
[0017]
Example 2
In the first embodiment, since one end of the pipe 3 protrudes from the flange 2 and the other end is located inside the flange, the pipe 3 has directionality and takes much time and effort to manufacture. As shown in FIG. The structure of the flange 2 can be economically manufactured as a single unit as the enlarged diameter portion 36 in which both ends of the pipe 3 are enlarged.
The connection of the unit is performed by inserting a connecting pipe 39 into the enlarged diameter portion 36 of the pipe 3 at the end of the unit, wherein O-rings are attached to both ends, and sleeves 38 each having a taper on both sides are attached at the center. Fix the pipe 3 to the flange.
[0018]
Example 3
In the first embodiment, since the unit has directionality in joining the units, when the pipe having the O-ring and the sleeve and the pipe having the enlarged diameter portion are fixed to the flange, they are alternately mounted in the circumferential holes. By doing so, the directionality of the unit is lost, and the production and on-site joining are facilitated.
[0019]
FIG. 7 shows a state in which the heat collecting tube unit 1 of the present invention is connected and inserted into the hole.
[0020]
【The invention's effect】
In the present invention, a corrosion-resistant metal tube having a large thermal conductivity is adopted as a heat collection tube, and the heat collection amount is increased by unitizing the heat collection tube so that a larger number of heat collection tubes than the conventional method can be inserted into the drilled hole.
In addition, the length of the unit is set to a length that can be transported by truck or the like, so that it can be easily connected with a flange, and a long heat sampling tube can be inserted and installed in the drilled hole efficiently.
[Brief description of the drawings]
FIG. 1 is a perspective view of a heat collection tube unit.
FIG. 2 is a perspective view in which a heat sampling tube unit provided with a U-shaped tube for a drill hole bottom is connected.
FIG. 3 is a plan view of a flange.
FIG. 4 is a sectional view of a flange portion of the heat collection tube unit.
FIG. 5 is a front view showing details of a joint end of the pipe.
FIG. 6 is a sectional view of a flange portion of a heat collection tube unit according to a second embodiment.
FIG. 7 is a cross-sectional view of a state in which the heat collection tube unit is installed in the hole.
FIG. 8 is a perspective view of various types of heat collecting tubes.
[Explanation of symbols]
1 Heat sampling tube unit 2 Flange 3 Pipe

Claims (5)

A heat collection tube unit in which an even number of corrosion-resistant metal pipes are fixed at both ends with annular flanges having holes for the pipes in the circumferential direction, and the pipes can be connected via the flanges. A heat collection tube unit in which a U-shaped pipe is attached so as to connect opposed holes of an annular flange provided with holes for pipes in a circumferential direction. In claim 1, an O-ring is provided at one end of the pipe, and a sleeve having a taper is attached to the pipe and fixed to the flange. The other end is an enlarged diameter portion capable of accommodating the O-ring and fixed to the flange. Has a sampling tube unit. 2. The heat collection tube unit according to claim 1, wherein both ends of the pipe are enlarged, and the pipes are connected by connecting short pipes having O-rings at both ends and a taper toward both sides at the center. 2. The heat collecting tube unit according to claim 1, wherein a pipe having an O-ring at one end and a sleeve at the other end and a pipe having an enlarged diameter portion are alternately fixed to a flange.

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