KR101499768B1 - Construction method of vertical type geothermal exchanger using safety guide - Google Patents

Abstract

The present invention relates to a method for constructing a vertically-closed type submerged heat exchanger using a safety guide, in which a submerged heat exchanger is provided with a safety guide provided with a predetermined dropping rod or the like at an end portion thereof directed toward the underground, The U-band is prevented from colliding with the bottom of the bore hole when the ground heat exchanger is inserted, and the one or more spacer members are spaced apart from each other by a predetermined distance The U-band is further protected, and an underground heat exchanger can be inserted into the bore hole.

Description

TECHNICAL FIELD [0001] The present invention relates to a vertical airtight submerged heat exchanger construction method using a safety guide,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a vertical closed type submerged heat exchanger construction method, and more particularly, to a vertical closed type submerged heat exchanger construction method using a U-tube type heat exchanger (U-tube pipe)

Humans have long been using various heat sources for heating or cooling. Recently, the international community is making efforts to minimize carbon emissions due to global warming.

The development of new and renewable energy utilization technology is a demand of the times, and it is also the mission of this era that the earth will be passed on to the descendants thoroughly. Among them, the use of geothermal heat is getting a lot of attention as a breakthrough technology for reducing the use of fossil fuels. However, it has a disadvantage that the initial investment cost is higher than other technologies of using heat energy.

Of the technologies for utilizing geothermal heat, a vertically-closed type geothermal heat exchanger uses heat transfer media (medium) irrespective of presence or absence of ground water, and is disclosed in Korean Patent No. 10-0985854 and No. 10-0981527.

The U-tube heat exchanger (U-tube tube) 10 is installed in the borehole 100 as shown in Fig.

To this end, the soil is first pierced through the soil layer (1) and the boundary layer (2) in a vertical direction until the rock layer (3) is exposed and then the outcasing (4) is installed to prevent the soil from falling down and contamination of surface water The U-tube heat exchanger (U-tube 10) is inserted into the rock layer 3, and then the grouting operation is performed.

The U-tube (10) is composed of a supply pipe and a return pipe, and is connected to a heat pump (not shown). Then, a grouting operation is performed in the bore hole 100 so that heat conduction between the U-tube tube 10 and the rock layer 3 is smooth.

At this time, the U-tube 10 is connected to the lower end of the bore hole by a U-band. The U-tube 10 is a continuous tube of a certain length (for example, a length of 150 m) which is stronger than the impact of a PVC tube, and a PE pipe made of HDPE (high density polyethylene) is used.

However, the PE pipe has a small specific gravity and is difficult to insert into the borehole 100 filled with groundwater because it is light. In addition, when the U-tube 10 is inserted, the U-band portion is difficult to descend vertically, so that it collides with the rock fragments protruding from the inner wall of the bore hole and is damaged. In the vicinity of the U-band, The U-band is easily broken. Particularly, when the U-band is broken, there is a problem that the cost of construction such as the entire inserted U-tube 10 must be removed and reinstalled.

In Korean Patent No. 10-1065330 (underground heat exchanger construction method), a rope member is formed outside the lower stiffener of the underground excavator so that one end of the rope is connected to the upper retractor and the other end is connected to the rope hanger And inserting the U-tube tube into the underground excavator.

However, since the prior art has to connect the rope to each bore hole, it is troublesome to apply it to a case where a plurality of bore holes are drilled. In particular, in the case of deep and small bore holes, , The U-band portion connecting the rope at the time of upward pulling of the rope may be damaged by the pulling force, and the U-band breakage problem still remains.

Korean Patent Laid-Open No. 10-2008-0009844 (an underground heat exchanger pipe having a connecting member) discloses a pipe in which a supply pipe, a water return pipe and a connecting member are integrally formed.

Although the prior art can prevent U-band breakage by twisting, it is still difficult to insert into the borehole due to buoyancy of the groundwater, and there is a possibility that the U-band collides with the inner wall of the borehole and is damaged.

In Korean Patent No. 10-0958208 (a geothermal underground heat exchanger with improved heat exchange performance), a body for separating an inlet pipe and an outlet pipe from each other in a non-contact manner, and a bending unit And a load member formed of a weight and a weight formed by the U-band portion.

However, in the above-mentioned prior art, it is troublesome to separately provide the spacing member and the weight, and the load of the weight is concentrated in the U-band, and the impact when the weight is further touched to the bottom of the borehole is transmitted to the U- Electrolytes can still remain and the possibility of fracture of the U-band still remains.

On the other hand, after the U-tube 10 is inserted into the bore hole 100, bentonite, which is generally higher in thermal conductivity than water, is used as a grout.

However, when the bentonite mixed with water through the injection pipe (Trami pipe) is filled from the bottom of the bore hole in the conventional manner, when the underground water etc. are accumulated in the bore hole due to the water expansion characteristic of the bentonite, There has been a problem that the efficiency of the grouting operation is deteriorated.

In addition, when the bentonite is used as the grout material because the groundwater in the borehole is contained in the vicinity of the shore, the bonding property of the bentonite is inhibited and the grouting material can not exhibit its original function.

BRIEF SUMMARY OF THE INVENTION The present invention is conceived to solve the problems of the prior art described above, and it is an object of the present invention to prevent U-band from colliding with the bottom of a bore hole when a U-tube type underground heat exchanger is inserted into a borehole formed in an underground rock layer, And to provide a method of constructing a vertical closed type submerged heat exchanger by using a safety guide that easily vertically descends.

According to another aspect of the present invention, there is provided a method of constructing an underground heat exchanger including a first step of forming a borehole having a predetermined depth in a basement, a second step of inserting an underground heat exchanger into the borehole, And a third step of grouting the bottom of the underground heat exchanger, wherein the second step comprises attaching a safety guide to an underground portion of the underground heat exchanger toward the underground, And a heat exchanger inserted into the bore hole, wherein the safety guide includes a drop bar provided to be capable of sinking the buoyancy of the groundwater in the bore hole and capable of sinking; A seating guide attached to a distal end of the dropping bar; And at least one spacer member spaced from the seating guide in the longitudinal direction of the drop bar and fastened to the drop bar.

The underground heat exchanger is a U-tube type heat exchanger, and the seating guide has an opening so as to be inserted into a U-band of the U-tube type heat exchanger. It is another feature of the base construction method.

The seating guide is formed with the opening at a lower portion thereof. The center of each of the spacer members is formed with a cylindrical insertion port so that the drop bar is inserted and fixed by a predetermined fastener. The U- Another aspect of the method for constructing an underground heat exchanger according to the present invention is that a concave connection portion is formed symmetrically so as to be coupled to a supply pipe and a water return pipe of a heat exchanger.

Further, each of the spacer members is fastened to the feed pipe of the U-tube type heat exchanger located at the connection portion and the lower end portion of the return pipe with tape, and is another feature of the method of constructing the underground heat exchanger according to the present invention.

The dropping rod is a tube stick having a water-expandable grout material filled in a packing member having a metal or a plurality of micropores having a specific gravity larger than that of water, the seating guide is made of an elastic material, and each of the spacer members is made of plastic Another feature of the method of constructing an underground heat exchanger according to the present invention is that it is formed.

The first step includes drilling the soil layer and the boundary layer in the vertical direction until the rock layer is exposed, and then installing the outcasing, wherein the third step includes the step of removing, from the bottom of the bore hole, (3-1) filling up to the upper end, (3-2) filling up to the bottom of the out casing, And filling the upper portion of the borehole with an aggregate having an average diameter of 10 mm or less up to a height to which the safety guide is attached when the dropping bar is formed of the metal, When the drop bar is formed of the tube stick, the water expandable grout material is expanded by water or moisture in the bore hole to rupture and fill the packing member, and in the step 3-2, the aggregate having an average diameter of 11 to 30 mm And the step 3 - 3 is filled with non-shrinkage mortar. The method for constructing the underground heat exchanger according to the present invention is further characterized in that:

In the present invention, a safety guide provided with a predetermined drop rod or the like is attached to an end portion of the underground heat exchanger facing the underground, so that the underground heat exchanger not only buoys the underground water but also easily sinks, The U-band is prevented from colliding with the bottom of the borehole when inserting the underground heat exchanger, and the U-band is further protected by making at least one spacer member to separate the supply pipe and the return pipe from each other without being twisted, So that it is possible to insert and install the machine.

In addition, when the drop bar is formed of a tube stick filled with a water inflating grout material in a packing member having a plurality of micropores formed therein, the drop bar can be automatically filled up to a predetermined height from the bottom of the bore hole without injecting additional grout material.

Further, the step of filling the borehole is divided into the steps from the bottom of the borehole to the position of the safety guide, to the rock layer, and the step of filling the ground, and by changing the grout material in each step, the heat conduction performance to the underground heat exchanger is improved, It is possible to effectively block the inflow of contaminants and to construct an underground heat exchanger without any spatial limitations such as a coastal area.

FIG. 1 is a cross-sectional view illustrating an installation of an underground heat exchanger according to an embodiment of the present invention. Referring to FIG.
FIG. 2 is a cross-sectional view illustrating a state in which grouting is performed according to an embodiment of the present invention.
3 is an exploded perspective view showing the configuration of the safety guide shown in FIG.
FIG. 4 is a perspective view showing a state in which the safety guide shown in FIG. 3 is fastened to the U-tube type heat exchanger.

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

As shown in FIGS. 1 and 2, a method of constructing an underground heat exchanger according to an embodiment of the present invention includes a first step S1 of forming a bore hole 100 having a predetermined depth in a basement, A second step S2 of inserting the underground heat exchanger 200 into the hole 100 and a third step S3 of filling the bore hole 100 and performing grouting.

1, a safety guide 20 is attached to an end portion of the underground heat exchanger 200 facing the underground, and the safety guide 20 is connected to the underground heat exchanger 200 200 are inserted into the bore hole 100.

1, the underground heat exchanger 200 is a U-tube type heat exchanger 10, and the inserting safety guide is configured to overcome the buoyancy of groundwater in the borehole 100, A dropping rod 21 provided so as to be able to rotate; A seating guide (23) attached to the tip of the drop bar (21); And at least one spacer member (25, 27, 29) spaced from the seating guide (23) in the longitudinal direction of the drop bar (21) and fastened to the drop bar (21).

When the safety guide 20 is inserted into the bore hole 100 after being fastened to the U-tube heat exchanger 10, the drop rod 21 has a function of fastening the respective components of the safety guide 20 at the center, The borehole 100 can be formed into a rod having a predetermined length by a metal material having a specific gravity much greater than that of water.

Although the drop bar 21 is not shown, the drop bar 21 is formed to have a predetermined length by a tube stick filled with a water expandable grout material (for example, bentonite) in a packing member having a plurality of micropores formed therein, The inflatable grout material is inflated by water or moisture in the borehole without injecting the filling material, so that the packing member can be ruptured to automatically fill the borehole from the bottom to a predetermined height.

In the latter case, the grout material is a mixture of 20 to 30 wt% of bentonite and 70 to 80 wt% of a silica sand, and the packing member is any one selected from the group consisting of paper, synthetic resin and vinyl (especially, hard polyethylene) The micropores may be implemented to have a smaller size than the bentonite and the silica sand.

3, the seating guide 23 is attached to the distal end of the drop rod 21 to protect the U-band 16 from being directly closed to the bottom of the bore hole 100 as shown in Fig. 1 .

Therefore, the seating guide 23 is attached to the tip of the drop rod 21 so that the safety guide 20 according to the present embodiment is fastened to the underground heat exchanger 200 and then the U- 3, a specific example of the seat guide 23 has an opening at the bottom to be inserted into the U-band 16 of the U-tube heat exchanger 10, and U - It is shown as a rod bent to surround the band 16, but it is possible to be in plane or mesh form.

Since the opening guide 23 is for inserting the seating guide 23 into the U-band 16, it can be formed on a side surface other than the lower side, and when the seating guide 23 is a rod, Of course.

In this case, the end of the seat guide 23 is connected to the inner wall of the bore hole 100 when the U-tube type heat exchanger 10 is inserted. It is preferable that the U-band 16 be bent in an inward direction (see FIG. 4) so as not to catch it.

1, the seating guide 23 is formed of an elastic material to relieve an impact due to the load of the dropping rod 21 and the underground heat exchanger 10 when it touches the bottom of the borehole 100 desirable. For example, if the drop bar 21 is made of cast iron, the seating guide 23 can be formed of steel having elasticity.

Since the one or more spacer members 25, 27 and 29 are fastened to the drop bar 21 and fixed to the lower end of the U-tube heat exchanger 10, .

For example, each of the spacer members may be connected and supported between the drop bar 21 and the supply pipe 12 or the water return pipe 14 of the U-tube type heat exchanger 10, and as shown in FIG. 3, The cylindrical inlet 22 is formed to be inserted into the rod 21 and fixed by a predetermined fastener 28. The cylindrical inlet 22 is formed at both ends thereof with a concave connecting portion 22 to be fastened to the supply pipe 12 and the water return pipe 14 of the U- The heat exchanger 26 is formed and can be fastened to the lower end of the U-tube heat exchanger 10 as shown in Fig. 4 (a).

When the spacer members 25, 27 and 29 are fastened to the lower end of the supply pipe 12 and the return pipe 14 of the U-tube type heat exchanger 10 with the same structure as the latter, , The both end connecting portions 26 of the respective spacer members are positioned at the lower end of the supply pipe 12 and the water return pipe 14 of the U-tube type heat exchanger and are fastened to the banding 32 of the tape 30 as shown in Fig. So that it is preferable to fasten it.

As shown in Fig. 4 (b), the tape 30 surrounds the supply pipe 12 and the water return pipe 14 of the U-tube type heat exchanger and each spacer member and is bent 32, After the fastening, when the U-tube heat exchanger 10 is inserted into the bore hole 100, the impact that can be received from the bottom of the bore hole can be relieved secondarily.

That is, when the U-tube heat exchanger 10 touches the bottom of the bore hole 100, the impact is firstly relieved by the seat guide 23, and secondarily, the seat guide 23 -> the drop rod 21, The impact is transmitted to the respective spacer members 25, 27 and 29 so that the connecting portions 26 at both ends of the spacer members 25, 27 and 29 are connected to the supply pipe 12 of the U- It is pushed up along the pipe (14) and exhausts the impact.

Thus, the conventional problem that the U-band 16 of the U-tube heat exchanger 10 is damaged by being directly contacted with the bottom of the bore hole 100 can be fundamentally solved.

4, the spacer member is inserted into the drop bar 21 and has a symmetrical structure on both sides. The spacer member is spaced apart from the drop bar 21 by a predetermined distance in the longitudinal direction thereof and fastened to the drop bar 21 , Both ends of which are fixed from the lower end of the supply pipe 12 and the water return pipe 14 of the U-tubular heat exchanger, the supply pipe 12 of the U-tubular heat exchanger joined via the U- The twist of the water return pipe 14 can be prevented.

The spacer members 25, 27 and 29 are formed of a plastic material having a low thermal conductivity (for example, a hard polyethylene material) so that mutual thermal interference between the supply pipe 12 and the return pipe 14 can be maximized .

3, the third step S3 includes filling the first grout material 110 from the bottom of the bore hole 100 to the height of the safety guide 20, (3-2) filling the second grout material (120) to the rock layer (3) of the bore hole (100); And filling the third grout material 130 up to the upper portion of the bore hole (i.e., up to the ground surface).

If the drop rod 21 is formed of metal, the aggregate having an average diameter of 10 mm or less up to the height to which the safety guide 20 is attached may be used as the first grout material 110 to fill the gaps between the spacer members 25, 27, 29 of the safety guide 20 so as to increase the thermal conductivity.

At this time, if the aggregate has a size exceeding 10 mm by a natural stone, an artificial stone, or a silica sand in an acid, a steel or the like, the space between the spacer members 25, 27 and 29 of the safety guide 20 is completely filled, Therefore, it is preferable to use a high-density stone having an average diameter of 10 mm or less and an average density of 3,203 kg / m 3 and a thermal conductivity of 3,462 W / m ° C.

When the drop bar (21) is formed as a tube stick in another embodiment, a water inflating grout material (e.g., water) used as the first grout material (110) by water (ground water) or moisture in the bore hole , Bentonite) is expanded and the packing member surrounding it expands and is automatically filled. Therefore, it is not necessary to inject the first grout material 110 separately.

In the step 3-2, an aggregate having an average diameter of 11-30 mm is filled as the second grout material 120 from the portion filled in the previous step, so that the thermal conductivity transmitted from the rock layer 3 is converted into water ). Specifically, the second grout material 120 may be a natural or artificial stone having an average diameter of 11 to 30 mm, and may be a medium density stone having an average density of 2,803 kg / m 3 and a thermal conductivity of 2,423 W / m ° C.

In this step, the second grout material 120 is preferably filled up to the rock layer 3 of the borehole 100, but it may be filled up to the bottom of the outcasing 4 as shown in FIG.

Next, in the step 3-3, the remaining via hole 100 is filled with the non-shrinkage mortar as the third grout material 130, thereby preventing external contaminants from flowing into the via hole 100 to contaminate the ground water , The ground subsidence of the landfill is also prevented, and the HDPE (high density polyethylene) pipe normally used in the U-tube type heat exchanger 10 can be prevented from being damaged.

Here, the use of the non-shrinkable mortar is intended to prevent the problem that shrinkage occurs in the curing process when general cement mortar is used, and the heat transfer effect due to the shrinkage is lowered.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It is intended to be within the scope of the invention.

1: soil layer
2: boundary layer
3:
4: Out casing
10: U-tube heat exchanger (U-tube)
12: Supply pipe
14: Water pipe
16: U-band
20: Safety guide
21: Drop bar
22: Cylindrical inserting hole
23: Seat Guide
24: spacer member arm
25, 27, 29:
26: Connection
28: Fastener
30: tape
32: Banding
100: bore hole
200: Underground heat exchanger

Claims (6)

A first step of forming a borehole having a predetermined depth in the ground, a second step of inserting an underground heat exchanger into the borehole, and a third step of grouting by burying the borehole, In the base construction method,
The second step is to attach a safety guide to an end of the underground heat exchanger facing the basement so that the underground heat exchanger is inserted into the bore hole with the safety guide,
In the safety guide,
A dropping bar provided to be capable of sinking the buoyancy of the groundwater in the borehole;
A seating guide attached to a distal end of the dropping bar; And
And at least one spacer member spaced from the seating guide in the longitudinal direction of the drop bar and fastened to the drop bar.
The method according to claim 1,
The underground heat exchanger is a U-tube type heat exchanger,
Wherein the seating guide has an opening to be inserted into the U-band of the U-tube heat exchanger and is bent to surround the U-band.
3. The method of claim 2,
Wherein the seating guide has an opening at a lower portion thereof,
A cylindrical insertion port is formed in the center of each of the spacer members so that the drop rod is inserted and fixed by a predetermined fastener,
Wherein the spacer members are symmetrically formed at both ends of the spacer members so as to be coupled to the supply pipe and the water return pipe of the U-tube type heat exchanger.
The method of claim 3,
Wherein the spacer members are fastened to the feed pipe of the U-tube type heat exchanger located at the connection portion and the lower end portion of the return pipe by tape.
5. The method according to any one of claims 1 to 4,
Wherein the drop bar is a tube stick filled with a water expandable grout material in a packing member formed with a metal or a plurality of micropores having a specific gravity larger than that of water,
The seating guide is formed of an elastic material,
Wherein each of the spacer members is formed of a plastic material having a low thermal conductivity.
6. The method of claim 5,
Wherein the first step includes drilling through the soil layer and the boundary layer in the vertical direction until the rock layer is exposed, and then installing the outcasing,
(3-1) filling the bottom of the bail hole to the top of the drop rod of the safety guide, (3-2) filling the bottom of the outcasing, And filling the upper portion of the bore hole up to the upper portion of the bore hole,
In the step 3-1, when the drop bar is formed of the metal, it is filled with an aggregate having an average diameter of 10 mm or less up to the height to which the safety guide is attached. When the drop bar is formed into the tube stick, The water expandable grout material is inflated with moisture to rupture and fill the packing member,
In the step 3-2, an aggregate having an average diameter of 11 to 30 mm is filled,
And the step (3-3) is filled with non-shrinkage mortar.

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