Underground heat exchange structure and heat exchange well

Abstract

The utility model provides an underground heat exchange structure and a heat exchange well, and relates to the technical field of underground heat exchange, the underground heat exchange structure comprises at least two first pipes, the lower ends of the at least two first pipes are connected through a connecting pipe, and a slow flow structure is arranged in each first pipe; the flow slowing structure comprises two mounting plates and at least one coiled pipe arranged between the two mounting plates, the mounting plates are connected with the inner wall of the first pipe, and the coiled pipe penetrates through the two mounting plates; the lower end of the second pipe is connected with the connecting pipe, so that the second pipe is communicated with the first pipe through the connecting pipe; one end of the heat exchange water circulation structure is connected with the first pipe, the other end of the heat exchange water circulation structure is connected with the second pipe, and the heat exchange water circulation structure is used for enabling heat exchange water to flow into the first pipe and flow out of the second pipe; the problems that in the prior art, an underground heat exchange structure adopts a straight hole type structure as a circulating working medium flowing channel, the circulating working medium flowing process is likely to be caused, and the heat exchange effect is affected are solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of underground heat exchange, and more specifically, relates to an underground heat exchange structure and a heat exchange well. Background Art

[0002] Geothermal energy is a green energy source. The utilization of geothermal energy is increasingly attracting people's attention, especially the use of downhole heat exchangers to extract geothermal energy, which has two major economic and social benefits. Downhole heat exchangers exchange heat with the fluid in the wellbore and the surrounding porous layer in a natural convection manner. In order to accelerate the circulation of the downhole heat exchanger and the fluid in the wellbore and improve the heat exchange capacity, it is necessary to try to strengthen the natural convection heat exchange between the surface of the downhole heat exchanger and the fluid in the wellbore.

[0003] Patent document No. CN113124579A discloses a non-interference downhole heat exchanger for converting abandoned wells into geothermal wells, which is mainly used in abandoned well conversion projects, including an outer casing and a central tube arranged in the outer casing; and a porous heat exchange tube, wherein the porous heat exchange tube includes an inner ring wall and an outer ring wall, wherein the inner ring is provided with an intermediate channel having an inner diameter consistent with the inner diameter of the central tube, and a capillary channel is provided between the inner ring wall and the outer ring wall, which is beneficial to increase the contact area between the circulating working fluid and the heat conducting material and improve the heat exchange efficiency; the upper end of the porous heat exchange tube is respectively connected to the outer casing and the central tube, and the capillary channel is provided between the inner ring wall and the outer ring wall ... capillary channel, and the capillary channel is provided between the inner ring wall and the capillary channel, and the capillary channel is provided between the inner ring wall and the capillary channel, and the capillary channel is provided between the inner ring wall and the capillary channel, and the capillary channel is provided between the inner ring wall and the capillary channel, and the capillary channel The central tube is connected, and a plug is provided at the lower end of the porous heat exchange tube; the inner ring wall is provided with an insulating layer, the purpose of which is to prevent the heat loss of the circulating working fluid in the process of flowing into the central tube. The circulating working fluid flows from the outer sleeve into the capillary pores of the porous heat exchange tube. The heat of the geothermal layer is transferred to the porous heat exchange tube by heat conduction. The porous heat exchange tube then transfers the heat to the circulating working fluid in the capillary pores by heat transfer. The heated circulating working fluid enters the plug at the lower end of the porous heat exchange tube, and then the circulating working fluid enters the central tube through the middle pore of the porous heat exchange tube, and finally the circulating working fluid returns to the ground through the central tube. The contact area between the circulating working fluid and the heat-conducting material can be increased through the above-mentioned capillary pores, but when the circulating working fluid flows, since the capillary pores still adopt a straight hole structure, it is easy to cause the circulating working fluid to flow too fast, thereby affecting the heat exchange effect. Utility Model Content

[0004] The purpose of the utility model is to provide a downhole heat exchange structure and a heat exchange well in view of the deficiencies existing in the prior art, so as to solve the problem that the downhole heat exchange structure in the prior art adopts a straight hole structure as the flow channel of the circulating working fluid, which easily causes the flow process of the circulating working fluid and affects the heat exchange effect.

[0005] In order to achieve the above-mentioned purpose, the utility model provides a downhole heat exchange structure, comprising:

[0006] At least two first tubes, the lower ends of at least two of the first tubes are connected by a connecting tube, a slow-flow structure is arranged inside each of the first tubes, the slow-flow structure comprises two mounting plates and at least one serpentine tube arranged between the two mounting plates, the mounting plates are connected to the inner walls of the first tubes, and the serpentine tube runs through the two mounting plates;

[0007] a second tube, the lower end of which is connected to the connecting tube, so that the second tube is connected to the first tube through the connecting tube;

[0008] A hot water circulation structure, one end of which is connected to the first pipe, and the other end of which is connected to the second pipe, and is used to allow the hot water to flow into the first pipe and flow out of the second pipe.

[0009] Optionally, a fixing plate is provided at the upper ends of the first tube and the second tube, and the first tube and the second tube pass through the fixing plate and are fixedly connected to the fixing plate.

[0010] Optionally, a connecting frame is provided on the outer side of the second tube, and the second tube is connected to the outer wall of the first tube through the connecting frame.

[0011] Optionally, the inner wall of the second tube is provided with a heat insulating layer.

[0012] Optionally, the water exchange water circulation structure includes a circulating water container and an injection pipe and an output pipe connected to the circulating water container, the injection pipe and the output pipe are connected to the first pipe and the second pipe respectively, and an injection pump is provided on the injection pipe.

[0013] Optionally, two first tubes are provided, and one second tube is provided, and the two first tubes are provided on both sides of the second tube.

[0014] Optionally, each of the slow-flow structures includes two serpentine tubes, the serpentine tubes include a water inlet part, a serpentine part and a water outlet part connected in sequence from top to bottom, the two mounting plates are a first mounting plate and a second mounting plate, the water inlet part and the water outlet part respectively pass through the first mounting plate and the second mounting plate, and are respectively connected to the first mounting plate and the second mounting plate.

[0015] Optionally, the axes of the water inlet and the water outlet are parallel to the axis of the first tube, the serpentine portion includes alternately arranged curved pipe sections and straight pipe sections, and the axes of the straight pipe sections are perpendicular to the axis of the first tube.

[0016] The utility model also provides a heat exchange well, comprising:

[0017] Well body;

[0018] In the above-mentioned underground heat exchange structure, the first tube and the second tube of the underground heat exchange structure are arranged in the well body, and the hot water circulation structure is arranged above the well body.

[0019] Optionally, a fixing plate is provided at the upper end of the first tube and the second tube, and the first tube and the second tube pass through the fixing plate and are fixedly connected to the fixing plate; a cement layer is provided on the inner wall of the well body, and a step structure with a variable diameter is formed at the upper end of the cement layer, and the fixing plate is clamped and fixed to the step structure.

[0020] The utility model provides an underground heat exchange structure and a heat exchange well, which have the beneficial effects of: the underground heat exchange structure connects the lower ends of a first tube and a second tube through a connecting tube to form a circulating flow channel for hot water exchange, a slow flow structure is arranged inside each first tube, the slow flow structure is connected to the inner wall of the first tube through two mounting plates, and at least one serpentine tube is arranged between the two mounting plates, and the arrangement of the serpentine tube can change the flow path of the hot water exchange, slow down the flow rate of the hot water exchange, increase the heat exchange time, and improve the heat exchange effect.

[0021] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present invention.

[0023] Figure 1 A schematic diagram of a downhole heat exchange structure according to the first embodiment of the utility model is shown.

[0024] Figure 2 A schematic diagram of a slow flow structure of a downhole heat exchange structure according to the first embodiment of the utility model is shown.

[0025] Figure 3 Show Figure 1 A is an enlarged structural diagram of FIG.

[0026] Figure 4 A schematic structural diagram of a heat exchange well according to the second embodiment of the utility model is shown.

[0027] Figure 5 A schematic diagram of the external structure of a heat exchange well according to the second embodiment of the utility model is shown.

[0028] Description of reference numerals:

[0029] 1. First pipe; 2. Connecting pipe; 3. Slow-flow structure; 4. Serpentine pipe; 5. Second pipe; 6. Fixed plate; 7. Connecting frame; 8. Insulation layer; 9. Injection pipe; 10. Output pipe; 11. Injection pump; 12. Water inlet; 13. Water outlet; 14. First mounting plate; 15. Second mounting plate; 16. Bend section; 17. Straight section; 18. Well body; 19. Cement layer; 20. Step structure. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0031] In order to solve the problem that the downhole heat exchange structure in the prior art adopts a straight hole structure as the flow channel of the circulating working medium, which easily causes the flow process of the circulating working medium and affects the heat exchange effect; the utility model provides a downhole heat exchange structure, including:

[0032] At least two first tubes, the lower ends of the at least two first tubes are connected by a connecting tube, a slow flow structure is arranged inside each first tube, the slow flow structure comprises two mounting plates and at least one serpentine tube arranged between the two mounting plates, the mounting plates are connected to the inner wall of the first tube, and the serpentine tube runs through the two mounting plates;

[0033] A second pipe, the lower end of which is connected to the connecting pipe, so that the second pipe is connected to the first pipe through the connecting pipe;

[0034] The hot water circulation structure has one end connected to the first pipe and the other end connected to the second pipe, and is used to allow the hot water to flow into the first pipe and flow out from the second pipe.

[0035] Specifically, the first tube and the second tube of the underground heat exchange structure are used to be arranged in the heat exchange well, and the lower ends of the first tube and the second tube are connected by a connecting tube to form a circulating flow channel for hot water exchange. The hot water exchange water flows into the first tube and flows out of the second tube through the hot water exchange circulation structure, thereby realizing the circulating flow of the hot water exchange. A slow flow structure is arranged inside each first tube, and the slow flow structure is connected to the inner wall of the first tube through two mounting plates, and at least one serpentine tube is arranged between the two mounting plates. The arrangement of the serpentine tube can change the flow path of the hot water exchange, slow down the flow rate of the hot water exchange, increase the heat exchange time, and improve the heat exchange effect.

[0036] Optionally, a fixing plate is provided at the upper ends of the first tube and the second tube, and the first tube and the second tube pass through the fixing plate and are fixedly connected to the fixing plate.

[0037] Specifically, the fixing plate is used to be connected to the outer walls of the first tube and the second tube, and is used to fix the first tube and the second tube. The fixing plate can be fixed at the wellhead of the heat exchange well.

[0038] Optionally, a connecting frame is provided on the outer side of the second tube, and the second tube is connected to the outer wall of the first tube through the connecting frame.

[0039] Specifically, the connecting frame connects the second pipe with the first pipe to limit the relative position relationship between the second pipe and the first pipe, thereby improving the structural stability of the underground heat exchange structure when in use.

[0040] Optionally, the inner wall of the second tube is provided with a heat insulating layer.

[0041] Specifically, the provision of the thermal insulation layer can reduce the heat loss of the hot water after underground heat exchange and ensure the utilization rate of geothermal energy.

[0042] Optionally, the hot water circulation structure includes a circulating water container and an injection pipe and an output pipe connected to the circulating water container, the injection pipe and the output pipe are connected to the first pipe and the second pipe respectively, and an injection pump is provided on the injection pipe.

[0043] Specifically, the circulating water container is used to store hot water. Under the pumping action of the injection pump, the hot water can be injected into the first tube through the injection pipe and flow downward along the first tube. During this process, the hot water passes through the slow flow structure and flows downward through the serpentine tube, slowing down the flow rate, increasing the heat exchange time, and improving the heat exchange effect. After that, the hot water enters the connecting tube and flows upward along the second tube. After passing through the second tube, it is output through the output pipe and enters the circulating water container, thereby realizing the heat exchange of the hot water and extracting geothermal energy.

[0044] Optionally, two first tubes are provided, and one second tube is provided, and the two first tubes are provided on both sides of the second tube.

[0045] Specifically, the second tube is arranged at the center of the heat exchange well, the two first tubes are arranged on opposite sides of the second tube, and the lower ends of the first tube and the second tube are connected through a U-shaped connecting tube.

[0046] In one example, a plurality of first tubes may be provided, and the plurality of first tubes are evenly distributed around the second tube, and the lower ends thereof are connected via a connecting tube with a radial structure.

[0047] Optionally, each slow-flow structure includes two serpentine tubes, the serpentine tubes include a water inlet part, a serpentine part and a water outlet part connected in sequence from top to bottom, the two mounting plates are respectively a first mounting plate and a second mounting plate, the water inlet part and the water outlet part respectively pass through the first mounting plate and the second mounting plate, and are respectively connected to the first mounting plate and the second mounting plate.

[0048] Specifically, the slow-flow structure separates the lower part of the first tube by a first mounting plate and a second mounting plate spaced apart from top to bottom, and a serpentine tube is arranged between the first mounting plate and the second mounting plate. The serpentine tube serves as a flow channel for hot water exchange and plays a role in slowing the flow.

[0049] In one example, each slow-flow structure includes a plurality of serpentine tubes, and the plurality of serpentine tubes guide the hot water at the same time.

[0050] Optionally, the axes of the water inlet and the water outlet are parallel to the axis of the first tube, the serpentine portion includes alternately arranged curved pipe sections and straight pipe sections, and the axis of the straight pipe section is perpendicular to the axis of the first tube.

[0051] Specifically, the hot water flows downward into the first tube, enters the water inlet of the serpentine tube, and then flows through the curved pipe section and the straight pipe section to complete the heat exchange. The hot water and the curved pipe section have a certain impact, which slows down the flow rate of the hot water.

[0052] The utility model also provides a heat exchange well, comprising:

[0053] Well body;

[0054] In the above-mentioned downhole heat exchange structure, the first tube and the second tube of the downhole heat exchange structure are arranged in the well body, and the water exchange water circulation structure is arranged above the well body.

[0055] Specifically, the well body passes through multiple rock and soil layers, and the first tube and the second tube of the above-mentioned underground heat exchange structure are arranged in the well body. The hot water circulation structure arranged on the ground realizes the circulation of hot water in the first tube and the second tube, thereby realizing heat exchange and extracting geothermal energy.

[0056] Optionally, a fixing plate is provided at the upper ends of the first tube and the second tube, and the first tube and the second tube pass through the fixing plate and are fixedly connected to the fixing plate; a cement layer is provided on the inner wall of the well body, and a step structure with a variable diameter is formed at the upper end of the cement layer, and the fixing plate is clamped and fixed to the step structure.

[0057] Specifically, the first tube and the second tube are connected to the step structure at the wellhead through the fixing plate at their upper ends. A step structure with an enlarged aperture is provided at the upper end of the cement layer at the wellhead. The fixing plate is installed from top to bottom and clamped on the step structure to fix the insertion depth of the first tube and the second tube in the well.

[0058] Embodiment 1

[0059] like Figures 1 to 3 As shown, the utility model provides a downhole heat exchange structure, comprising:

[0060] At least two first tubes 1, the lower ends of at least two first tubes 1 are connected by a connecting tube 2, a slow flow structure 3 is arranged inside each first tube 1, the slow flow structure 3 includes two mounting plates and at least one serpentine tube 4 arranged between the two mounting plates, the mounting plates are connected to the inner wall of the first tube 1, and the serpentine tube 4 runs through the two mounting plates;

[0061] A second tube 5, the lower end of which is connected to the connecting tube 2, so that the second tube 5 is connected to the first tube 1 through the connecting tube 2;

[0062] The hot water circulation structure has one end connected to the first pipe 1 and the other end connected to the second pipe 5 , and is used to allow the hot water to flow into the first pipe 1 and out of the second pipe 5 .

[0063] In this embodiment, the connecting pipe 2 is a U-shaped pipe.

[0064] In this embodiment, a fixing plate 6 is provided at the upper ends of the first tube 1 and the second tube 5 , and the first tube 1 and the second tube 5 pass through the fixing plate 6 and are fixedly connected to the fixing plate 6 .

[0065] In this embodiment, a first hole and a second hole are formed inside the fixing plate 6 , and the first tube 1 and the second tube 5 pass through the first hole and the second hole respectively and are connected to the inner walls of the first hole and the second hole respectively.

[0066] In this embodiment, a connecting frame 7 is provided on the outer side of the second tube 5 , and the second tube 5 is connected to the outer wall of the first tube 1 through the connecting frame 7 .

[0067] In this embodiment, a third hole and a limiting groove are provided inside the connecting frame 7 , the second tube 5 passes through the third hole, and each first tube 1 can be embedded in a limiting groove.

[0068] In this embodiment, the inner wall of the second tube 5 is provided with a heat insulating layer 8 .

[0069] In this embodiment, the heat insulating layer 8 is formed by coating the inner wall of the second pipe 5 with a heat insulating material.

[0070] In this embodiment, the hot water circulation structure includes a circulating water container and an injection pipe 9 and an output pipe 10 connected to the circulating water container. The injection pipe 9 and the output pipe 10 are respectively connected to the first pipe 1 and the second pipe 5. An injection pump 11 is provided on the injection pipe 9.

[0071] In this embodiment, the injection pump 11 is a high-pressure pump.

[0072] In this embodiment, two first tubes 1 are provided, and one second tube 5 is provided, and the two first tubes 1 are provided on both sides of the second tube 5 .

[0073] In this embodiment, each slow-flow structure 3 includes two serpentine tubes 4, which include an inlet portion 12, a serpentine portion and an outlet portion 13 connected in sequence from top to bottom, and the two mounting plates are a first mounting plate 14 and a second mounting plate 15, respectively. The inlet portion 12 and the outlet portion 13 pass through the first mounting plate 14 and the second mounting plate 15, respectively, and are connected to the first mounting plate 14 and the second mounting plate 15, respectively.

[0074] In this embodiment, the axes of the water inlet 12 and the water outlet 13 are parallel to the axis of the first tube 1 , and the serpentine portion includes alternately arranged curved pipe sections 16 and straight pipe sections 17 , and the axis of the straight pipe section 17 is perpendicular to the axis of the first tube 1 .

[0075] Embodiment 2

[0076] like Figure 4 and Figure 5 As shown, the utility model also provides a heat exchange well, comprising:

[0077] Well 18;

[0078] In the above-mentioned downhole heat exchange structure, the first pipe 1 and the second pipe 5 of the downhole heat exchange structure are arranged in the well body 18 , and the water exchange water circulation structure is arranged above the well body 18 .

[0079] In this embodiment, a fixing plate 6 is provided at the upper ends of the first tube 1 and the second tube 5, and the first tube 1 and the second tube 5 pass through the fixing plate 6 and are fixedly connected to the fixing plate 6; a cement layer 19 is provided on the inner wall of the well body 18, and a step structure 20 with a variable diameter is formed at the upper end of the cement layer 19, and the fixing plate 6 is clamped and fixed to the step structure 20.

[0080] In summary, the heat exchange well provided by the utility model has the above-mentioned underground heat exchange structure arranged in its well body 18. The well body 18 is opened underground and passes through multiple rock and soil layers. A cement layer 19 is poured inside the well body 18. The first pipe 1 and the second pipe 5 of the underground heat exchange structure are fixed in the well body 18 through a fixing plate 6, and the second pipe 5 is connected to the first pipe 1 through a connecting frame 7 to increase stability during use; when in use, the injection pump 11 is started to allow the hot water to enter the first pipe 1, and the hot water flows downward and flows through the slow flow structure 3. The setting of the serpentine pipe 4 slows down the flow rate of the hot water, increases the heat exchange time, and improves the heat exchange effect; the hot water after heat exchange passes through the connecting pipe 2 and enters the second pipe 5, flows upward in the second pipe 5 until it is output through the output pipe 10, thereby realizing the extraction of geothermal energy so as to utilize the geothermal energy.

[0081] The various embodiments of the utility model have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A downhole heat exchange structure, characterized in that: include: At least two first tubes, the lower ends of at least two of the first tubes are connected by a connecting tube, a slow-flow structure is arranged inside each of the first tubes, the slow-flow structure comprises two mounting plates and at least one serpentine tube arranged between the two mounting plates, the mounting plates are connected to the inner walls of the first tubes, and the serpentine tube runs through the two mounting plates; a second tube, the lower end of which is connected to the connecting tube, so that the second tube is connected to the first tube through the connecting tube; A hot water circulation structure, one end of which is connected to the first pipe, and the other end of which is connected to the second pipe, and is used to allow the hot water to flow into the first pipe and flow out of the second pipe.

2. The downhole heat exchange structure according to claim 1, characterized in that: A fixing plate is disposed at the upper ends of the first tube and the second tube, and the first tube and the second tube pass through the fixing plate and are fixedly connected to the fixing plate.

3. The underground heat exchange structure according to claim 1, characterized in that: A connecting frame is arranged on the outer side of the second tube, and the second tube is connected to the outer wall of the first tube through the connecting frame.

4. The underground heat exchange structure according to claim 1, characterized in that: The inner wall of the second tube is provided with a heat insulating layer.

5. The underground heat exchange structure according to claim 1, characterized in that: The water exchange water circulation structure includes a circulating water container and an injection pipe and an output pipe connected to the circulating water container. The injection pipe and the output pipe are connected to the first pipe and the second pipe respectively. An injection pump is provided on the injection pipe.

6. The underground heat exchange structure according to claim 1, characterized in that: Two first tubes are provided, and one second tube is provided, and the two first tubes are provided on both sides of the second tube.

7. The downhole heat exchange structure according to claim 1, characterized in that: Each of the slow-flow structures includes two serpentine tubes, and the serpentine tubes include a water inlet part, a serpentine part and a water outlet part connected in sequence from top to bottom. The two mounting plates are respectively a first mounting plate and a second mounting plate. The water inlet part and the water outlet part respectively penetrate the first mounting plate and the second mounting plate, and are respectively connected to the first mounting plate and the second mounting plate.

8. The downhole heat exchange structure according to claim 7, characterized in that: The axes of the water inlet and the water outlet are parallel to the axis of the first tube, the serpentine portion includes alternately arranged curved pipe sections and straight pipe sections, and the axes of the straight pipe sections are perpendicular to the axis of the first tube.

9. A heat exchange well, characterized in that: include: Well body; According to the downhole heat exchange structure according to any one of claims 1 to 8, the first tube and the second tube of the downhole heat exchange structure are arranged in the well body, and the hot water circulation structure is arranged above the well body.

10. The heat exchange well according to claim 9, characterized in that: A fixing plate is provided at the upper end of the first tube and the second tube, and the first tube and the second tube pass through the fixing plate and are fixedly connected to the fixing plate; a cement layer is provided on the inner wall of the well body, and a step structure with a variable diameter is formed at the upper end of the cement layer, and the fixing plate is clamped and fixed to the step structure.

Images