KR20190021122A - A method for protecting geothermal heat exchanging pipe by using protective pipe - Google Patents

Abstract

The present invention relates to a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe, and more particularly to, a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe for preventing a heat exchange pipe used for geothermal cooling and heating from being damaged by an external impact such as an excavator. The present invention includes a step of drilling a primary borehole by drilling a stratum in a direction perpendicular to the ground using a drill string having a drill bit coupled thereto at a lower end thereof; a step of inserting a protective pipe into the primary borehole; a step of drilling a secondary borehole for extension to a predetermined depth so that the heat exchange pipe is inserted into the primary borehole; a step of inserting the heat exchange pipe into the borehole; and a step of forming a grouting layer by injecting cement to the borehole to a predetermined height so that the heat exchange pipe does not move.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of protecting a heat exchange pipe for a geothermal heating /

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe and more particularly to a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe for preventing a heat exchange pipe used for geothermal cooling / .

Geothermal energy, which is a part of alternative energy, is used for power generation by using high-temperature geothermal heat in deep underground, and it is applied to heating and cooling system using geothermal heat at 10 ~ 20 ℃. It is applied to heating and cooling technology It is possible to save energy by 40% or more compared with the conventional heating and cooling apparatus, and it is known that it can reduce the energy generation cost by 40 ~ 70%.

Geothermal energy development is as follows: First, there is a small-scale vertical closed-type geothermal technology that drills a depth of 30 ~ 200m and uses a heat pump to heat and cool. Second, it drills 300 ~ 500m of small diameter and circulates underground groundwater directly And third, the method used in the Hassan region to drill more than 1000m of small diameter and bring the high temperature water above 200 ℃ directly to the ground to generate the geothermal power. Fourth, It can be roughly classified into deep geothermal technology, which is a technique to draw up heat to the ground by circulating the geothermal circulation medium by drilling a large diameter of 5,000 meters and to heat the geothermal without heating the heat pump.

The geothermal heat pump system, which is an electric device using natural heat storage such as ground water for the purpose of cooling and heating the building using the geothermal heat, is equipped with a geothermal heat exchanger so that heat is released to the ground during the summer season by the heat exchanger, So that the cooling and heating performance is not lowered due to the geothermal temperature maintaining a substantially constant temperature at 10 to 20 ° C throughout the year, and stable operation is possible.

The conventional cooling and heating apparatus using geothermal heat is composed of a geothermal exchanger for recovering geothermal heat and a heat pump for cooling and heating by moving the recovered geothermal heat to a required place.

However, such a system must be installed before the construction of the facility, and the heavy equipment such as an excavator is used to destroy the heat exchange pipe while performing the terrage and the ground reinforcement work, thereby increasing the time and cost required for the construction of the building There is a problem.

Korean Utility Model Registration No. 20-0417382 proposes a highly efficient geothermal heat exchanger for a heat pump, which protects the borehole from being broken by installing a steel pipe casing up to the depth of the soil in the borehole. However, in the earthquake- And the construction period is increased. Further, as the depth of the soil layer becomes deeper, the length of the steel pipe casing is increased, which is uneconomical.

Korean Patent Laid-Open Publication No. 10-2015-0094040 is related to a cooling / heating underground heat exchange system using geothermal heat. Since a grouting material is excessively consumed to form a grouting layer in the entire inside of a borehole into which a heat exchange pipe is inserted, There is a problem that an impact is transmitted to the heat exchange pipe when the grouting layer is broken due to a heavy equipment such as an excavator at the stage of the earthworks and the ground reinforcement.

Korean Patent Registration No. 10-0778936 discloses that a heat transfer grouting material is inserted into a borehole into which the heat exchange pipe is inserted to cure the material, and a cement grouting material is inserted thereinto to reinforce the ground. This is because the heat transfer grouting layer and the cement grouting material The grouting material is excessively consumed to form the layer, which is uneconomical. In addition, the casing is inserted to the boundary between the soil layer and the rock layer to prevent the ground from being weakened during excavation. However, the depth of the soil layer increases the length of the casing, which is uneconomical.

Korean Utility Model Registration No. 20-0417382 (Feb. 22, 2006) Korean Patent Publication No. 10-2015-0094040 (Aug. Korean Registered Patent No. 10-0778936 (November 16, 2017)

The object of the present invention is to prevent the heat exchange pipe used in the geothermal cooling and heating from being damaged due to an external impact and to reduce the time and cost that can be unnecessarily required for the construction of the building as the heat exchange pipe is broken, To provide a method for protecting a heat exchange pipe for cooling and heating a geothermal heat.

Another object of the present invention is to provide a geothermal cooling and heating system using a protective tube for preventing the soil layer from being collapsed and damaging the heat exchange pipe when the heat exchange pipe is installed on a ground layer composed of a relatively weak soil layer as compared with a rock layer. To provide a pipe protection method.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, according to a preferred embodiment of the present invention, there is provided a method for protecting a heat exchange pipe for a geothermal cooling / heating system using a protective pipe, comprising a drill string coupled with a drill bit at a lower end thereof, Drilling the primary borehole; Inserting a protective pipe into the primary borehole; Drilling the secondary borehole so that the primary borehole extends to a predetermined depth so that the heat exchange pipe is inserted; Inserting the heat exchange pipe into a borehole; And forming a grouting layer by injecting cement to a predetermined height to the borehole so that the heat exchange pipe does not move.

Preferably, the inner diameter of the primary borehole is larger than the inner diameter of the secondary borehole, the inner diameter of the protective pipe is greater than or equal to that of the secondary borehole, and the outer diameter of the protective pipe is smaller than the inner diameter of the primary borehole. do.

Preferably, the length of the protective pipe is 2 to 5 m.

Preferably, the method further comprises the step of covering an end cap inside the heat exchange pipe so that foreign matter is not inserted from the outside.

Preferably, the method further comprises the step of inserting a marking tool into the layer so as to identify the position of the heat exchange pipe, characterized in that the marking tool is formed of a colored cloth or vinyl .

According to the present invention, the method for protecting a heat exchange pipe for geothermal heating and cooling using the protective pipe of the present invention is such that the upper end of the heat exchange pipe is covered with a protective pipe to prevent the heat exchange pipe for geothermal cooling and heating from being damaged due to an external impact, , It is possible to reduce the time and cost that can be unnecessarily consumed in the construction of the building due to the breakage of the heat exchange pipe.

In addition, according to the present invention, when the heat exchange pipe is installed on a stratum composed of a relatively weak soil layer as compared with the rock layer, it is possible to prevent the heat exchange pipe from being collapsed by protecting the heat exchange pipe with a protective pipe, have.

1 is a flowchart of a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe according to a preferred embodiment of the present invention.
2 is a schematic representation of a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe according to a preferred embodiment of the present invention.
FIG. 3 is a schematic view of a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe according to a preferred embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. &Quot; and / or "include each and every combination of one or more of the mentioned items. ≪ RTI ID = 0.0 >

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

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

FIG. 1 is a flowchart of a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe according to a preferred embodiment of the present invention, and FIG. 3 is a schematic view according to FIG.

1 and 3, a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe is as follows.

First, when the heat exchange pipe installation work for geothermal heating and cooling starts, the primary borehole 30 is excavated (S10).

The primary borehole 30 should be excavated to a predetermined depth in a direction perpendicular to the stratum using a drill string (not shown) with a drill bit (not shown) at the lower end thereof.

The drill bit can be used in consideration of the material, shape and the like according to the ground condition of the excavation target area. Preferably, a metal drill bit is used for soft rock and heavy rock excavation, and a diamond drill bit is used for excavation of shear rock and extreme shear rock.

In addition, it is possible to provide a pleasant environment to the workers by preventing the dust that may be generated in the process of excavating the stratum by applying the wet drill bit.

The drill bit receives rotary force by a rotary drive unit (not shown) equipped with a motor, and is rotated to excavate the ground layer.

Next, a protective pipe 10 for protecting the heat exchange pipe 20 is inserted (S20).

The outer diameter of the protective pipe 10 is preferably smaller than the inner diameter of the primary borehole 30 so that the protective pipe 10 is inserted along the inner wall of the primary borehole 30.

The protective pipe 10 is preferably formed of a steel pipe, which is a concept including a steel product having a cylindrical shape with an empty space therein.

The length of the protective pipe 10 is preferably 2 to 5 m. If the length of the protection pipe is less than 2 m, the heat exchange pipe can not be sufficiently protected and foreign substances may enter the heat exchange pipe. If the length of the protection pipe is 5 m or more, the length is too long, which is inefficient.

Next, the secondary borehole 32 is drilled to a predetermined depth into which the heat exchange pipe 20 is inserted (S30).

It is preferable that the inner diameter of the primary borehole 30 is larger than the inner diameter of the secondary borehole 32 and the inner diameter of the protective pipe 10 is greater than or equal to the secondary borehole 32.

The depth of the borehole can be changed according to the geothermal energy generation technology. When using the small diameter vertically sealed type geothermal technology that uses the heat pump using the heat pump, it is possible to excavate a depth of 30 ~ 200m, circulate the groundwater directly, In case of using the small-diameter tubular type geothermal technology, it is possible to excavate a depth of 300 ~ 500m. In case of using geothermal power generation technology, Lt; / RTI >

Next, the heat exchange pipe 20 is inserted into the borehole (S40).

In general, PE pipes and PVC pipes are widely used in the heat exchange pipe 20, and the heat exchange pipe 20 is preferably formed of a synthetic resin pipe such as polystyrene (PE).

Next, in order to prevent the heat exchange pipe 20 from moving, the grouting material is injected into the borehole up to a predetermined height to form a grouting layer 40 (S50).

The grouting material is a concept including bentonite obtained by mixing cement mixed with a metal material having a high thermal conductivity or a metal material having a high thermal conductivity so that the heat of the stratum can be conducted to the heat exchange pipe 20 well.

The bentonite is a kind of clay mainly composed of montmorillonite, and the montmorillonite is formed into a crystal structure showing a fine, thin plate shape. In the crystal structure, there is a gap between the base layers, and exchangeable cations and water are contained in the base layer. They absorb a large amount of water depending on the surrounding conditions, and dehydrate them to change the layer spacing.

Because of the nature of these constituent minerals, bentonite is characterized by large shrinkage and expansion of the volume during drying and wetting. Actually, bentonite reacts with water under water to 5 times its normal weight and 13 to 16 times its volume Free-swelling to a thixotropic gel-state material.

The bentonite is classified into various types of bentonite depending on which component is substituted with a deficient charge.

Sodium bentonite is mainly used for sodium bentonite, calcium bentonite, and calcium bentonite. Sodium bentonite is superior to sodium bentonite because of its superior physical properties.

As such, bentonite reacts with water and has swelling property. In addition, it has a thickening and lubrication ability to concentrate other materials having low viscosity because it forms an adhesive or gel state in which other materials are mixed with other materials.

Meanwhile, the position of the heat exchange pipe 20 can be identified by inserting a display tool (not shown) in the layer where the heat exchange pipe 20 is installed. The display tool may be formed of a colored cloth or vinyl to facilitate removal after the construction is completed.

2 is a schematic representation of a method for protecting a heat exchange pipe for geothermal cooling and heating using a protective pipe according to a preferred embodiment of the present invention.

It is preferable that the heat exchange pipe 20 is inserted in a U-shape so as to circulate the heat medium in a closed manner.

An end cap (22) is installed on the upper end of the heat exchange pipe (20). The end cap 22 prevents the heat medium circulating inside the heat exchange pipe 20 from being contaminated by foreign substances that may flow from the outside during construction.

Then, in order to apply the heat pump for cooling and heating using the geothermal heat as a heat source, the end cap 22 may be removed and connected to the heat exchange pipe 20.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

10: Protective Pipe
20: Heat exchange pipe
22: End Cap
30: Primary borehole
32: Second borehole
40: Grouting layer

Claims (5)

Drilling a first borehole by drilling a stratum in a direction perpendicular to the ground using a drill string coupled with a drill bit at the bottom;
Inserting a protective pipe into the primary borehole;
Drilling the secondary borehole so that the primary borehole extends to a predetermined depth so that the heat exchange pipe is inserted;
Inserting the heat exchange pipe into a borehole; And
And forming a grouting layer by injecting cement to a predetermined height to the borehole so that the heat exchange pipe does not move. The method according to claim 1,
Wherein the inner diameter of the primary borehole is larger than the inner diameter of the secondary borehole and the inner diameter of the protective pipe is greater than or equal to that of the secondary borehole and the outer diameter of the protective pipe is smaller than the inner diameter of the primary borehole. Protection method of heat exchange pipes for geothermal heating and cooling. 3. The method of claim 2,
Wherein the length of the protection pipe is 2 to 5 m. The method according to claim 1,
Further comprising the step of covering an end cap inside the heat exchange pipe so as to prevent foreign matter from being inserted into the heat exchange pipe. The method according to claim 1,
Inserting a marking tool into the stratum so as to identify the location of the heat exchange pipe, characterized in that the marking tool is formed of a colored cloth or vinyl, How to protect heat exchange pipes for heating and cooling.

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