KR102118986B1 - Soil Heat Exchanger - Google Patents

Abstract

The present invention provides an underground heat exchanger including: an inlet pipe for supplying heat-exchanged heat medium from a heat pump to one side of a bore hole formed in the ground; a return pipe arranged to surround the outer circumferential surface of the inlet pipe to exchange heat with an underground heat source and discharging the heat back to the heat pump; a thermal insulation layer interposed between the inlet pipe and the return pipe to prevent heat exchange between the heat medium moving between the inlet pipe and the return pipe; and a heat absorbing unit disposed on the outer circumferential surface of the return pipe to increase the underground heat source and a heat exchange area inside the bore hole.

Description

Underground heat exchanger {Soil Heat Exchanger}

The present invention relates to an underground heat exchanger, and more particularly, to an underground heat exchanger that is inserted into a bore hole in the underground and heats using an underground heat source.

In general, energy sources used for home and industrial heating and cooling include fossil fuels such as petroleum or natural gas, or nuclear fuels. The use of these energy sources not only creates a major cause of environmental pollution, but also limits the amount of reserves, thus developing alternative energy. It is actively progressing.

As an energy source used for heating and cooling, fossil fuels such as coal, oil, and natural gas are used, or energy produced by using fossil fuels or nuclear power is mainly used.

However, fossil fuels have a disadvantage of polluting the water quality and the environment due to various pollutants generated in the combustion process, and in recent years, alternative energy development has been actively conducted to replace them.

Among these alternative energy sources, research on wind power, solar heat, and geothermal energy, which has an infinite energy source, and air-conditioning and heating devices using the same are used. These energy sources have the advantage of obtaining energy with little effect on air pollution and climate change. On the other hand, there is a disadvantage that the energy density is relatively low.

In particular, in order to obtain energy using wind power and solar heat, a large area must be secured along with the limitations of the installation location, and these devices have a small energy production capacity per unit device and a high cost for installation and maintenance.

Geothermal energy, which is a member of alternative energy, is used for power generation by using geothermal heat in the deep underground as a heat source, and is applied to heating and cooling systems using geothermal heat at 10~20℃. When applied, it is known that energy savings of up to 40% or more can be achieved, and energy generation costs of 40-70% can be reduced compared to conventional air conditioning and heating devices.

Underground heat exchangers, which exchange heat using natural heat sources such as groundwater for the purpose of cooling and heating in buildings using such geothermal heat, place at least one or more underground heat exchangers inside the basement to release heat to the ground in the summer and from the ground in the winter. As a device that absorbs heat, it is possible to operate stably because the cooling and heating performance does not deteriorate through the underground heat source, which maintains a constant temperature of 10~20℃ throughout the year.

The underground heat exchanger that is commonly used is coupled to a cooling and heating system using geothermal heat, and is composed of a heat exchange pipe for recovering geothermal heat and a heat pump for heating and cooling air by moving the geothermal heat recovered from the heat exchange pipe to a required place.

The underground heat exchanger excavates a plurality of boreholes at a depth of about 150 m in the soil layer of the surface, and a U-shaped underground heat exchanger is inserted in each borehole, and heat exchange of the heat medium such as the underground heat source and the refrigerant to be supplied to the heat pump This is done.

However, the underground heat exchanger as described above, the heat exchange pipe is buried in a bore hole in a U-shape to exchange heat in the supply and discharge process of the heating medium, and it is difficult to buried in the bore hole while maintaining a constant distance between the supply pipe and the discharge pipe, A problem has been pointed out that variations occur in heat exchange efficiency depending on the interval.

The present invention is to solve the above problems, by arranging the inlet pipe and the return pipe inside the pipe made of one pipe can maintain a constant distance between the inlet pipe and the return pipe, and also the heat exchange efficiency constant The purpose is to provide a sustainable underground heat exchanger.

The present invention for achieving the above object is an inlet pipe for supplying heat exchanged heat medium from the heat pump to one side of the bore hole formed in the ground; A return pipe disposed to surround the outer circumferential surface of the inlet pipe to exchange heat with the heat source of the underground and heat medium to discharge the heat pump again; An heat insulating layer interposed between the inlet pipe and the return pipe to prevent heat exchange between heat pipes flowing between the inlet pipe and the return pipe, and an endothermic heat disposed in the outer circumferential surface of the return pipe to increase the underground heat source and heat exchange area inside the bore hole It provides an underground heat exchanger, characterized in that it comprises a.

The underground heat exchanger may further include a direction changing unit for switching the direction of the heat medium from the inlet pipe to the return pipe from the other side of the bore hole.

The heat insulating layer may be formed to be spaced a predetermined distance between the inlet pipe and the return pipe.

The inlet pipe and the return pipe may each have a ratio of a cross-sectional area or volume in a range of 1:1.2 to 1:1.7.

The heat medium discharged to the return pipe may have a slower flow rate than the heat medium supplied to the inlet tube.

The heat absorbing portion may be formed in a curved or flat pattern that is close to the distance from the outer circumferential surface of the return pipe.

The heat absorbing portion may be formed in a pattern that alternately repeats contact and non-contact along the circumferential direction on the outer circumferential surface of the return pipe.

The heat absorbing portion may be formed with a through pattern so that grouting filled in the bore hole may be introduced into a space between at least part of the heat absorbing portion and the return pipe.

In addition, the present invention is an inlet pipe for supplying heat exchanged heat medium from a heat pump to one side of a bore hole formed in the ground; A return pipe that is spaced apart from the inlet pipe in the borehole to exchange heat with the heat source in the ground and discharge it back to the heat pump; An insulating layer interposed in a space between the inlet pipe and the return pipe to prevent heat exchange between heat pipes flowing between the inlet pipe and the return pipe, and disposed on an outer circumferential surface of the inlet pipe and the return pipe to exchange heat with underground heat inside the bore hole It provides an underground heat exchanger comprising a; heat absorbing portion to increase the area.

When the inlet pipe and the return pipe and the heat insulating layer are combined, one cross-section may be formed of any one of circular, elliptical and polygonal shapes.

The return pipe may be at least equal to or larger than the cross-sectional area or volume of the inlet pipe.

The heat absorbing portion may be formed with a through pattern so that grouting filled in the bore hole may be introduced into a space between at least part of the heat absorbing portion and the return pipe.

The inlet pipe and the return pipe or the inlet pipe, the return pipe and the heat insulating layer may be integrally formed inside one pipe.

The insulating layer may have a larger thickness than an upper region where the inlet pipe and the return pipe are inserted into the bore hole, and a lower region where the inlet pipe and the return pipe are connected to each other.

According to the underground heat exchanger according to the present invention,

First, it is easy to install inside the borehole by placing the inlet pipe and the return pipe inside one pipe,

Second, by providing an insulating layer between the inlet pipe and the return pipe, heat can be continuously exchanged in the direction of return from the intake of the heat medium,

Third, since the heat medium is slower in the return direction than the inlet direction, it is possible to increase the heat exchange time with the heat source in the ground.

Fourth, when a grouting pattern is formed in the heat absorbing part and the grouting is injected into the bore hole, the grouting is partially introduced into the through hole pattern to increase heat exchange performance.

1 is a reference diagram schematically showing a state in which an underground heat exchanger according to an embodiment of the present invention is installed.
Figure 2 is a side view showing a part of the outer shape of the underground heat exchanger according to the first embodiment of the present invention.
3 is a cross-sectional view showing a cross section of the underground heat exchanger shown in FIG. 2.
4 is a cross-sectional view showing an underground heat exchanger according to a second embodiment of the present invention.
FIG. 5 is an enlarged reference diagram showing a part of both end portions of the underground heat exchanger shown in FIG. 4.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described so that those skilled in the art can easily carry out. It should be noted that, in the accompanying drawings, the same reference number is used when the same number is indicated in the other drawings. In addition, in the description of the present invention, when it is determined that detailed descriptions of related well-known functions or known configurations may unnecessarily obscure the subject matter of the present invention, detailed descriptions thereof will be omitted. In addition, certain features shown in the drawings are enlarged or reduced or simplified for ease of description, and the drawings and their components are not necessarily drawn to scale. However, those skilled in the art will readily understand these details.

1 is a reference diagram schematically showing a state in which an underground heat exchanger according to an embodiment of the present invention is installed.

Referring to Figure 1, the underground heat exchanger 100 is installed inside a bore hole (Bore Hole; h) formed to a depth of about 150 ~ 200m in the ground is connected to one side and the air conditioning system using geothermal heat. At this time, the underground heat exchanger 100 may excavate a plurality of bore holes according to the performance of an air conditioning system using geothermal heat, and may be installed in each bore hole.

The underground heat exchanger 100 may be supplied to a heating/cooling system, that is, a heat pump 20 using geothermal heat, after heat exchange with geothermal (ground heat source) in the ground by injecting heat medium such as water or refrigerant. In addition, the heat pump 20 may exchange heat with the heat medium supplied from the underground heat exchanger 100 again to heat or cool the air through the indoor unit of the customer 10, or to supply hot water or to operate the boiler.

Here, the demand destination 10 includes a house or barn or a company or government office where people or livestock can live in a space of a certain area.

The heat pump 20 is a well-known technique, and more specifically, an evaporator for evaporating the refrigerant, a compressor for compressing the evaporated refrigerant from the evaporator to discharge a refrigerant of high temperature design, and a refrigerant discharged from the compressor to condense It consists of a condenser and an expansion valve.

The heat pump 20 may be a cooling/heating device (for example, a boiler) that transfers a low-temperature heat source to a high temperature or induces a high-temperature heat source to a low temperature using the invention of condensation or heat of condensation.

FIG. 2 is a side view showing a part of the external shape of the underground heat exchanger according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view showing one cross section of the underground heat exchanger shown in FIG. 2.

1 to 3, the underground heat exchanger 100 according to the first embodiment of the present invention receives the heat medium from the heat pump (see FIGS. 1 and 20), and the underground direction D1 inside the bore hole h. ) Is supplied to the inlet pipe 110 and the inlet pipe 110 is disposed around the inlet pipe 110, the return pipe 120 for transferring the heat medium in the direction of the heat pump 20 again, and the inlet pipe 110 ) And the heat exchange layer 140 disposed on the outer circumferential surface of the heat exchange layer 130 and the heat exchange area 140 which are disposed between the heat exchange area.

First, the inlet pipe 110 is located in the inner central region of the return pipe 120. Therefore, the return pipe 120 is disposed to surround the inlet pipe 110 at equal intervals. Therefore, the heat medium supplied in the underground direction (D1) through the inlet pipe 110 is not significantly changed in temperature due to heat exchange. Of course, heat exchange may be performed in the process of supplying the heat medium in the underground direction D1 through the inlet pipe 110.

An insulating layer 130 is disposed on the outer circumferential surface of the inlet pipe 110 to prevent heat transfer by directly contacting the return pipe 120. The insulating layer 130 may be filled with air therein, or may be filled with an insulating material (not shown) that interferes with heat transfer. Therefore, the heat insulating layer 130 is provided to be spaced apart between the set pipe 110 and the return pipe 120.

Couplings for supplying heat medium from the heat pump 20 to the upper ends of the inlet tube 110 and the return tube 120, or to transfer the heat medium that has completed the heat exchange from the underground heat exchanger 100 to the heat pump 20 again. (Not shown) may be provided. Although the coupling is not shown in the drawing, there is an effect that can be easily combined in correspondence with the shape or position of the inlet pipe 110 and the return pipe 120.

In addition, at the lower end of the inlet pipe 110 and the return pipe 120, a direction changing unit (refer to FIG. 5, 300) connecting the inlet pipe 110 and the return pipe 120 is provided. The direction changing unit 300 supplies the heat medium in the underground direction (D1) from the inside of the inlet pipe 110 and then supplies the heat medium in the heat pump direction (opposite to the underground direction; D2) inside the return pipe 120. The supply direction of the heating medium can be switched.

In addition, the heat exchange pipe 120 exchanges heat with the underground heat source while supplying the heat medium from the ground in the heat pump direction D2. It is preferable that the supply speed of the heat medium supplied in the heat pump direction (D2) inside the return pipe (120) is slower than the supply speed of the heat medium supplied in the underground direction (D1) inside the inlet tube (110). Therefore, the ratio of the cross-sectional area or volume of the inlet pipe 110 and the return pipe 120 may be in the range of about 1:1.2 to 1:1.7. Most preferably, the cross-sectional area of the return pipe 120 compared to the inlet pipe 110 is 120 to 130%. Since the size of the return pipe 120 is larger than that of the inlet pipe 110, the flow rate of the heat medium supplied from the inside of the return pipe 120 is slower than the inside of the inlet pipe 110, and accordingly, the heat pump direction from the return pipe 120 ( In the process of supplying to D2), a time during which heat exchange is performed can be further secured, and of course, heat exchange efficiency may be increased.

Between the return pipe 120 and the heat insulating layer 130 is provided with a support 123 that maintains the gap between them. As illustrated in FIG. 2, the support part 123 is described as an example, but may be formed of a plurality of two or more. For example, it may be composed of two or three at equal intervals, and the support portion 123 may be configured in a distorted shape (for example, a pre-exhaust shape) so as to interfere with the transfer direction of the heating medium. In this way, the heat exchange performance can be increased by causing turbulence in the transfer direction of the heat medium through the shape in which the support part 123 is distorted.

On the outer circumferential surface of the return pipe 120, an endothermic portion 140 is provided to increase the heat exchange area with the underground heat source inside the bore hole h. The heat absorbing portion 140 is configured to increase the contact area, such as a corrugated cardboard or sandwich panel. For example, the heat absorbing part 140 may be provided in a curved surface or a flat pattern that becomes farther away from the outer circumferential surface of the return pipe 120 and then closes again. In addition, the heat absorbing unit 140 may be formed in a pattern that alternately repeats contact and non-contact along the circumferential direction on the outer circumferential surface of the return pipe 120.

In addition, a through-hole pattern p may be selectively formed in the heat absorbing portion 140 to communicate with the outside of the heat absorbing portion 140 on the outer circumferential surface of the return pipe 120. The through-hole pattern p may be formed in various sizes and shapes, and the main function is when the grouting is placed outside the heat-absorbing portion 140 inside the bore hole h, the grouting part absorbs the heat through the through-hole pattern p. ) It can be made to flow inside. When the through pattern p is formed in the heat absorbing portion 140, the heat exchange performance may be increased while grouting contacts the outer circumferential surface of the return pipe 120, and the heat absorbing area is partially disposed inside the grouting part. There is an effect that can increase the heat exchange efficiency by increasing. This is that the heat transfer area can be increased compared to a conventional underground heat exchanger equipped with an ordinary heat sink fin. In addition, the effect of maintaining the independence of the borehole in the long term can be expected compared to the conventional heat sink fin structure.

4 is a cross-sectional view showing an underground heat exchanger according to a second embodiment of the present invention, and FIG. 5 is a reference diagram showing an enlarged portion of both ends of the underground heat exchanger shown in FIG. 4.

4, the underground heat exchanger according to the second embodiment of the present invention (having the same position as the underground heat exchanger 100 of FIG. 1, 200) has one inlet pipe 210 and a return pipe 220 It is arranged to face each other while forming a pipe structure of.

At this time, an insulating layer 230 is provided between the inlet pipe 210 and the return pipe 220, and an endothermic portion 240 is provided on the outer circumferential surfaces of the inlet pipe 210 and the return pipe 220.

The inlet pipe 210 and the return pipe 220 are formed in a substantially semicircular tube shape, and as the insulating layer 230 is disposed between the inlet pipe 210 and the return pipe 220, the inlet pipe 210 and the return pipe 220 and the heat insulating layer 230 is composed of one circular pipe shape.

The insulating layer 230 has the largest thickness at one end (top region; 230a) connected to the heat pump (see FIG. 1, 20), and conversely, the thickness at the other end (bottom region; 230b) farthest from the heat pump. It can be formed small. This is because the difference between the heat energy of the heat medium inside one end of the inlet pipe 210 and one end of the return pipe 220 is large, and the thickness of the heat insulating layer 230 is thick, and the other end of the inlet pipe 210 is recovered. Since the other end of the tube 220 is a process in which heat exchange is already performed in the ground and supplied to the heat pump again, the difference in heat energy of the heat medium in this part is small, so the function of heat insulation is minimal, so the thickness of the heat insulating layer 230 is reduced. Can be minimized. Therefore, an unnecessary material cost of the heat insulating layer 230 can be reduced, and the volume occupied by the heat insulating layer 230 in the underground heat exchanger 200 can be reduced, thereby increasing heat exchange performance.

In addition, since the heat absorbing unit 240 is the same as the structure described in the above-described embodiment, a duplicate description is omitted.

In FIG. 5, the direction changing unit 300 may be coupled to be detachably attached to an end of the underground heat exchanger 200. The direction switching unit 300 provides a function to induce the heat medium supplied through the inlet pipe 210 to smoothly change direction in the direction of the return pipe 220. In addition, the direction changing unit 300 may have a round shape in the underground direction so that the underground heat exchanger 200 is inserted into the ground more easily. The direction changer 300 may have the same diameter as the outer circumferential surface of the underground heat exchanger 200 or may have a larger diameter.

On the outer circumferential surface of the direction changing part 300, a plurality of guide parts 310 for guiding the direction inserted into the ground may be formed at equal intervals. The guide part 310 further protrudes from the outer circumferential surface of the direction changing part 300. Therefore, the rigidity of the direction changing part 300 can be further reinforced, and the heat exchange performance of the heat medium flowing inside the direction changing part 300 can be increased by increasing the heat transfer area of the direction changing part 300.

A through hole 320 may be formed at an end of the direction changing part 300 to easily handle the direction changing part 300.

The underground heat exchanger 200 is separated so as to be detachable for each unit length, and the length may be increased in a combined manner. That is, a direction changing part 300 is coupled to the final end of the underground heat exchanger 200, and the length of the underground heat exchangers 200 can be adjusted while being combined in a combined manner according to the length inserted into the underground. Of course, when the length of the plurality of underground heat exchangers 200 is adjusted in a combined manner, the insulating layer 230 may also be adjusted in length in a combined manner.

In the above, although illustrated and described as a specific embodiment to illustrate the technical spirit of the present invention, the present invention is not limited to the same configuration and operation as the specific embodiment as described above, and various modifications are within the scope of the present invention. Can be carried out within. Therefore, such modifications should also be regarded as belonging to the scope of the present invention, and the scope of the present invention should be determined by the claims below.

100, 200: underground heat exchanger
110, 210: incoming pipe
120, 220: water pipe
130, 230: insulating layer
140, 240: endothermic
h: Borehole

Claims (14)

An inlet pipe supplying a heat medium having completed heat exchange from a heat pump to one side of a bore hole formed in the ground;
A return pipe disposed to surround the outside of the inlet pipe, the front surface of the outer circumference contacting a heat source in the ground to heat-exchange the heat medium, and then discharged again to the heat pump;
An insulating layer interposed between the inlet pipe and the return pipe to prevent heat exchange between heat mediums flowing between the inlet pipe and the return pipe, and
It is disposed on the outer circumferential surface of the water return pipe and an endothermic portion for increasing the heat exchange area with the underground heat source inside the bore hole.
The inlet pipe and the return pipe each have a ratio of a cross-sectional area or volume in a range of 1:1.2 to 1:1.7,
The speed of the heat medium that is exchanged with the underground heat source while being discharged from the return pipe is slower than the speed of the heat medium supplied to the inlet tube,
The heat absorbing part is arranged to alternately contact and non-contact while alternately encircling the curved pattern along the outer periphery of the return pipe, and forming a through hole pattern so that grouting filled in the bore hole flows into the inner space of the curved pattern. heat exchanger. The method according to claim 1,
In the other side of the bore hole, the underground heat exchanger further comprising a direction switching unit for switching the direction of the heat medium from the inlet pipe to the return pipe. The method according to claim 2,
The insulating layer,
Underground heat exchanger, characterized in that formed so as to be spaced a predetermined distance between the inlet pipe and the return pipe. delete delete delete delete delete An inlet pipe supplying a heat medium having completed heat exchange from a heat pump to one side of a bore hole formed in the ground;
A return pipe that is spaced apart from the inlet pipe in the borehole to exchange heat with the heat source in the ground and discharge it back to the heat pump;
An insulating layer interposed in a space between the inlet pipe and the return pipe to prevent heat exchange between heat mediums flowing between the inlet pipe and the return pipe, and
Includes a heat absorbing portion disposed on the outer circumferential surface of the inlet pipe and the return pipe to increase the heat exchange area with the underground heat source inside the bore hole.
The return pipe is formed larger than the cross-sectional area or volume of the inlet pipe,
The heat absorbing part is arranged to alternately contact and non-contact alternately while surrounding the curved pattern along the outer periphery of the return pipe, and forming a through pattern so that grouting filled in the bore hole flows into the inner space of the curved pattern. Underground heat exchanger characterized by. The method according to claim 9,
When the inlet pipe and the return pipe and the heat insulating layer are combined, an underground heat exchanger, characterized in that one cross section is formed of any one of circular, elliptical and polygonal shapes. delete delete The method according to claim 9,
An underground heat exchanger, wherein the inlet pipe and the return pipe or the inlet pipe, the return pipe and the heat insulating layer are integrally formed inside one pipe. The method according to claim 9,
The insulating layer,
An underground heat exchanger characterized in that the upper region where the inlet pipe and the return pipe are inserted into the bore hole has a greater thickness than the lower region where the inlet pipe and the return pipe are connected to each other.

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