Underground heat exchanger

Abstract

The utility model relates to an underground heat exchanger, which comprises: a pre-buried spiral pipe, which comprises a pipe body with an inlet and an outlet, and a plurality of heat exchange ribs arranged along the circumference and fixed on the inner wall of the pipe body; a core column, which is inserted into the pipe body of the pre-buried spiral pipe along the extension direction of the pre-buried spiral pipe and is fixed in the pipe body by the plurality of heat exchange ribs; and a flow passage, which is formed between the pre-buried spiral pipe and the core column and communicates the inlet and the outlet of the pipe body. The underground heat exchanger has higher heat exchange efficiency and better structural stability and durability.

Description

Technical Field

[0001] The embodiments of this utility model relate to the field of heat exchangers. More specifically, this utility model relates to an underground heat exchanger. Background Technology

[0002] As a key component in geothermal energy utilization, the performance of underground heat exchangers directly affects the efficiency and feasibility of geothermal energy utilization systems. For example, underground heat exchangers can be used in the thermal management system of energy storage devices to exchange heat with the underground soil, ensuring that the thermal management system can utilize geothermal energy to cool or heat the energy storage device, especially the built-in battery pack, through the underground heat exchanger.

[0003] Existing underground heat exchangers typically employ a single spiral tube structure, with the heat exchange medium (such as water or oil) flowing inside the spiral tube. While this allows for heat exchange between the medium and the soil through the tube, the heat exchange efficiency is relatively low. Therefore, there is an urgent need for an underground heat exchanger with higher heat exchange efficiency. Utility Model Content

[0004] In order to solve one or more of the technical problems mentioned above, this utility model provides an underground heat exchanger with higher heat exchange efficiency and better structural stability and durability.

[0005] This utility model provides an underground heat exchanger, comprising: a pre-embedded spiral tube, including a tube body having an inlet and an outlet, and a plurality of heat exchange ribs arranged circumferentially and fixedly disposed on the inner wall of the tube body; a core column, which is inserted into the tube body of the pre-embedded spiral tube along the extension direction of the pre-embedded spiral tube and fixed in the tube body by the plurality of heat exchange ribs; and a flow channel formed between the pre-embedded spiral tube and the core column and communicating with the inlet and outlet of the tube body.

[0006] This invention relates to an underground heat exchanger that significantly improves heat exchange efficiency by adding heat exchange support ribs and a core column inside the pre-embedded spiral tube. Specifically, the heat exchange support ribs are fixed to the inner wall of the tube, increasing the contact area between the heat exchange medium and the pre-embedded spiral tube. The core column brings the heat exchange medium closer to the tube body, allowing for more effective heat exchange with the underground soil as the medium flows through the flow channel between the pre-embedded spiral tube and the core column. This structural design not only improves heat exchange efficiency but also enhances the structural stability and durability of the underground heat exchanger, enabling it to maintain good performance under various geological conditions. Attached Figure Description

[0007] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0008] Figure 1 This diagram illustrates the usage status of the underground heat exchange system according to an embodiment of the present invention.

[0009] Figure 2 A top view of an underground heat exchange according to an embodiment of the present invention is shown;

[0010] Figure 3 A cross-sectional view of the underground heat exchange in an embodiment of the present invention is shown at the location of the insulation material.

[0011] Explanation of reference numerals in the attached drawings: 100, underground heat exchanger; 1, pre-embedded spiral tube; 11, tube body; 12, heat exchange support rib; 111, inlet; 112, outlet; 11a, liquid inlet section; 11b, liquid outlet section; 11c, cylindrical spiral section; 2, core column; 3, flow channel; 4, insulation material. Detailed Implementation

[0012] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0013] Figures 1 to 3 The structure of the underground heat exchanger according to embodiments of this utility model is shown in all examples. Figure 1 , Figure 2 and Figure 3As shown, the underground heat exchanger 100 includes a pre-embedded spiral tube 1. The pre-embedded spiral tube 1 includes a tube body 11 having an inlet 111 and an outlet 112, and a plurality of heat exchange support ribs 12 arranged circumferentially and fixed to the inner wall of the tube body 11. The underground heat exchanger 100 also includes a core column 2, which is inserted into the tube body 11 along the extension direction of the pre-embedded spiral tube 1 and fixed within the tube body 11 by the plurality of heat exchange support ribs 12. Furthermore, the underground heat exchanger 100 includes a flow channel 3, which is formed between the pre-embedded spiral tube 1 and the core column 2 and connects the inlet 111 and outlet 112 of the tube body 11. In use, the heat exchange medium (such as water or oil) enters the flow channel 3 through the inlet 111 of the pipe body 11 and then flows out of the flow channel 3 through the outlet 112 of the pipe body 11. During this process, the heat exchange medium can exchange heat with the underground soil through the pipe body 11 and heat exchange support 12 of the pre-embedded spiral pipe 1, and carry out the heat or cold energy for cooling or heating selected equipment such as energy storage equipment.

[0014] To consider the comprehensive requirements of heat exchange performance, corrosion resistance, mechanical strength, cost, and processing performance of the underground heat exchanger 100, and to achieve the optimal match between material properties and functional requirements, the pre-embedded spiral tube 1 can be made of stainless steel or copper, and the core column 2 can be made of resin or rubber. This ensures the long-term stable operation and efficient heat exchange of the underground heat exchanger 100. As a preferred example, the pre-embedded spiral tube 1 is made of 304L stainless steel, and the core column 2 is made of high-density polyethylene (HDPE). This can increase the lifespan of the underground heat exchanger 100 by 3 times, ensuring that it is virtually maintenance-free for 50 years.

[0015] Preferably, the heat exchange ribs 12 are configured to extend from the inlet 111 of the tube body 11 to the outlet 112 of the tube body 11, such that the flow channel 3 is divided into sub-channels equal in number by each heat exchange rib 12. The design of the heat exchange ribs 12 extending continuously from the inlet 111 to the outlet 112 of the tube body 11 not only helps to increase the contact area between the heat exchange medium and the embedded spiral tube 1, improving heat exchange efficiency, but also simplifies the manufacturing difficulty of the embedded spiral tube 1 and reduces manufacturing costs.

[0016] In this embodiment, at any radial section (reference) of the pre-embedded spiral pipe 1 Figure 2 In the underground heat exchanger 100, each heat exchange support rib 12 is either straight or curved. Straight or curved heat exchange support ribs 12 are easier to manufacture, reducing manufacturing costs, and also enhance the structural stability of the underground heat exchanger 100. It is important to emphasize that, compared to straight heat exchange support ribs 12, curved heat exchange support ribs 12 can further increase the contact area between the heat exchange medium and the pre-embedded spiral tube 1, thereby further improving heat exchange efficiency.

[0017] In this embodiment, there are 3-5 heat exchange support ribs 12, which are evenly distributed along the circumference of the inner wall of the tube body 11. The 3-5 evenly distributed heat exchange support ribs 12 ensure sufficient heat exchange area while avoiding excessive structural complexity, so that the underground heat exchanger 100 maintains high heat exchange performance while also having good economy and maintainability.

[0018] In this embodiment, the radial cross-sectional area of ​​the flow channel 3 of the underground heat exchanger 100 is 0.23 to 0.48 times the radial cross-sectional area of ​​the inner cavity of the tube body 11. Experimental verification shows that when the aforementioned conditions are met, the heat exchange performance and flow resistance of the underground heat exchanger 100 can be effectively balanced, ensuring both efficient heat exchange and avoiding excessive flow resistance.

[0019] In this embodiment, the pre-embedded spiral pipe 1 includes an inlet section 11a with an inlet 111, an outlet section 11b with an outlet 112, and a cylindrical spiral section 11c connecting the inlet section 11a and the outlet section 11b. The pre-embedded spiral pipe 1 is configured such that when the cylindrical spiral section 11c is buried underground, the inlet section 11a extends from the top of the cylindrical spiral section 11c toward the ground and exits through the ground, while the outlet section 11b extends from the bottom of the cylindrical spiral section 11c toward the ground and exits through the ground. Since the cylindrical spiral section 11c, as the main heat exchange part, is entirely buried underground and has a large area of ​​contact with the soil, the underground space can be utilized to the maximum extent for heat exchange. The inlet section 11a and the outlet section 11b ensure the smooth entry and exit of the heat exchange medium in the cylindrical spiral section 11c and facilitate the connection with external equipment.

[0020] As an example, the vertical height of the outlet section 11b is 10m-30m, the vertical height of the cylindrical spiral section 11c is 2m-5m, and the vertical height of the inlet section 11a is approximately equal to the vertical height of the outlet section 11b minus the vertical height of the cylindrical spiral section 11c. The research results show that a vertical height of the outlet section 11b within the range of 10m-30m ensures that the underground heat exchanger 100 can penetrate deep underground, thus effectively utilizing geothermal energy. Since the soil temperature at a depth of 10m-30m is relatively stable and less affected by surface temperature fluctuations, it is closer to the geothermal constant temperature layer, ensuring that the cylindrical spiral section 11c can utilize a stable ground temperature (16℃-22℃), while also considering the economics and feasibility of burial. That is, too shallow a depth may be greatly affected by surface temperature, while too deep a depth would result in higher burial costs. A vertical height of 2m-5m provides the cylindrical spiral section 11c with sufficient heat exchange area, improving the heat exchange efficiency of the underground heat exchanger 100.

[0021] In this embodiment, the underground heat exchanger 100 also includes insulation material 4, which can be selected as polyurethane foam or sponge, etc. The insulation material 4 is used to cover at least selected portions of the liquid outlet section 11b. These selected portions include the portion above ground and the portion above a predetermined underground depth, where the predetermined underground depth ranges from 3m to 8m. Considering that the soil temperature in the 3m-8m depth range is greatly affected by the ambient temperature and can easily reduce the effectiveness of the underground heat exchanger 100, the use of insulation material 4 can reduce heat exchange between the underground heat exchanger 100, especially the upper part of the liquid outlet section 11b, and the soil at this depth, reducing heat loss of the heat exchange medium during transport and easily improving the final cooling or heating effect.

[0022] As an example, the diameter of the cylinder containing the centerline of the cylindrical helical segment 11c (i.e., the line connecting the midpoints of the radial cross-section of the tube body) is 16 to 20 times the outer diameter of the tube body 11. Experimental verification shows that when the aforementioned conditions are met, the heat exchange performance, structural stability, and ease of installation of the underground heat exchanger 100 can be balanced. On the one hand, it ensures that the pre-embedded helical tube 1 has sufficient heat exchange area, allowing the heat exchange medium to undergo sufficient heat exchange when passing through the underground heat exchanger 100. On the other hand, it avoids the defects of poor structural stability and difficult installation caused by an excessively large diameter of the cylindrical helical segment 11c.

[0023] In summary, the underground heat exchanger 100 of the present invention has higher heat exchange efficiency and better structural stability and durability.

[0024] In the foregoing description of this application, unless otherwise expressly specified and limited, the terms "fixed," "installed," "connected," or "linked" should be interpreted broadly. For example, the term "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this application, those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0025] Based on the above description of this application, those skilled in the art will also understand that the terms used, such as "upper," "lower," "vertical," and "horizontal," which indicate orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings of this application. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as a limitation on the present invention.

[0026] Furthermore, the terms "first" or "second," etc., used in this application to refer to numbers or ordinal numbers are for descriptive purposes only and should not be construed as explicitly or implicitly indicating relative importance or specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0027] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of the present invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in the practice of the present invention. The appended claims are intended to define the scope of protection of the present invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. An underground heat exchanger, characterized in that, include: The embedded spiral pipe includes a pipe body with an inlet and an outlet, and multiple heat exchange ribs arranged circumferentially and fixed to the inner wall of the pipe body. The core column is inserted into the body of the pre-embedded spiral tube along the extension direction of the pre-embedded spiral tube and is fixed in the body of the tube by a plurality of heat exchange support ribs. A flow channel is formed between the pre-embedded spiral tube and the core column and connects the inlet and outlet of the tube body.

2. The underground heat exchanger according to claim 1, characterized in that, The embedded spiral tube is made of stainless steel or copper, and the core column is made of resin or rubber.

3. The underground heat exchanger according to claim 1 or 2, characterized in that, The heat exchange ribs extend from the inlet of the tube to the outlet of the tube, and the flow passage is divided into sub-channels equal in number by each of the heat exchange ribs.

4. The underground heat exchanger according to claim 3, characterized in that, In any radial section of the pre-embedded spiral tube, each of the heat exchange support ribs is either straight or arc-shaped.

5. The underground heat exchanger according to claim 3, characterized in that, The number of heat exchange support ribs is 3-5, and they are evenly distributed along the circumference inside the inner wall of the tube.

6. The underground heat exchanger according to claim 1, characterized in that, The radial cross-sectional area of ​​the flow channel is 0.23 to 0.48 times the radial cross-sectional area of ​​the inner cavity of the tube.

7. The underground heat exchanger according to claim 2, characterized in that, The pre-embedded spiral pipe includes an inlet section having the inlet, an outlet section having the outlet, and a cylindrical spiral section connecting the inlet section and the outlet section. The pre-embedded spiral pipe is configured such that when the cylindrical spiral section is buried underground, the inlet section extends from the top of the cylindrical spiral section toward the ground and exits through the ground, while the outlet section extends from the bottom of the cylindrical spiral section toward the ground and exits through the ground.

8. The underground heat exchanger according to claim 7, characterized in that, The vertical height of the liquid outlet section is 10m-30m, and the vertical height of the cylindrical spiral section is 2m-5m.

9. The underground heat exchanger according to claim 8, characterized in that, The underground heat exchanger also includes insulation material, which is used to cover selected parts of the liquid outlet section. The selected parts include the part above ground and the part above a predetermined underground depth, wherein the predetermined underground depth ranges from 3m to 8m.

10. The underground heat exchanger according to claim 7, characterized in that, The diameter of the cylinder containing the centerline of the cylindrical helical segment is 16 to 20 times the outer diameter of the tube.

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