A downhole heat exchanger based on rock and soil energy storage

Abstract

The utility model discloses a downhole heat exchanger based on rock and soil energy storage, including an outer sleeve and an inner sleeve, the inner wall of the outer sleeve is provided with multiple groups of spiral guide rails, the inner sleeve is rotated and inserted into the outer sleeve through a fixed frame, the end of the inner sleeve located inside the outer sleeve is fixedly provided with a conical cover, the inner wall of the conical cover is fixedly provided with a plurality of guide plates, the outer wall of the inner sleeve is fixedly provided with multiple groups of blades, and each group of the blades is correspondingly provided below each group of the spiral guide rails. The beneficial effect of the utility model is that the laminar flow state of the fluid is broken by the design of the spiral guide rail, the flow path and flow direction of the fluid are changed, the fluid is guided to rotate along the spiral guide rail, the fluid is prompted to form turbulence, more efficient heat conduction and lower energy loss are achieved, and at the same time, the circulating fluid is formed into a turbulent state, which can increase the impact on the inner wall of the outer sleeve and the outer wall of the inner sleeve, reduce the formation of scale and the adhesion of scale, and improve the service life.

Description

Technical Field

[0001] The utility model belongs to the field of geothermal energy storage and utilization, and in particular relates to an underground heat exchanger based on rock and soil energy storage. Background Art

[0002] Geothermal energy is natural heat extracted from the earth's crust. This energy comes from the molten rock inside the earth and exists in the form of heat. It is the energy that causes volcanic eruptions and earthquakes. Geothermal energy does not rely on non-renewable resources such as coal and oil. It is a clean energy that can provide more sustainable energy for the future.

[0003] In the process of geotechnical energy storage development and utilization, it is necessary to exchange energy between the fluid injected into the well and the underground geotechnical body to utilize the heat or cold energy stored in the geotechnical body and use it for heating, cooling or other energy needs. The inner and outer casings of the existing coaxial tube heat exchanger are both smooth petroleum casings. The heat exchange medium flows downward from the annulus between the outer and inner casings and returns from the inner casing after heat exchange. The heat conduction efficiency of the entire heat exchange process is low, and underground resources cannot be extracted more efficiently, which limits its use in practical applications.

[0004] Therefore, we need to design a downhole heat exchanger based on rock and soil energy storage to solve these problems. Utility Model Content

[0005] The problem to be solved by the utility model is to provide an underground heat exchanger based on rock and soil energy storage.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0007] A downhole heat exchanger based on rock and soil energy storage comprises an outer casing and an inner casing, wherein a plurality of groups of spiral guide rails are arranged on the inner wall of the outer casing, the inner casing is inserted into the outer casing by rotation through a fixing frame, a conical cover is fixedly arranged on the end of the inner casing located inside the outer casing, a plurality of guide plates are fixedly arranged on the inner wall of the conical cover, a plurality of groups of blades are fixedly arranged on the outer wall of the inner casing, and each group of blades is correspondingly arranged below each group of the spiral guide rails.

[0008] Preferably, a bottom plate is provided below the conical cover, and the bottom plate is sealingly connected to the outer sleeve.

[0009] Such an arrangement can prevent fluid leakage and avoid affecting groundwater.

[0010] Preferably, the number of the spiral guide rails in each group is three, the three spiral guide rails are evenly fixed on the inner wall of the outer sleeve along the circumference of the outer sleeve, and each of the spiral guide rails is provided with a guide groove, and the width of the outflow end on the guide groove does not exceed the width of the outflow end.

[0011] With such an arrangement, the three spiral guide rails in each group can ensure the pitch of the spiral guide rails and the length of each spiral guide rail, while avoiding mutual interference between adjacent spiral guide rails in each group.

[0012] Preferably, the number of blades in each group is five.

[0013] Such an arrangement can ensure that the fluid flowing through the guide grooves on the spiral guide rail exerts a continuous and balanced impact on the rotating blades, thereby avoiding gaps in the force applied to the blades when the number of blades is the same as or a multiple of the number of spiral grooves.

[0014] Preferably, a bearing is provided at the connection between the fixing frame and the inner sleeve.

[0015] Such an arrangement can reduce the friction between the inner sleeve and the fixed frame when the inner sleeve rotates, thereby increasing the rotation speed of the inner sleeve.

[0016] The advantages and positive effects of the utility model are:

[0017] 1. The utility model utilizes flowing heat-conducting fluid for circulation. The fluid flows downward from the annular gap between the inner and outer casings, absorbing or releasing heat to the surrounding strata. The entire system only takes energy but not water, and has no impact on groundwater resources.

[0018] 2. The utility model can be equipped with spiral guide rails of different pitches and widths and blades of different sizes and numbers according to the different diameters of geothermal wells to meet the processing requirements of different heat transfer fluids and has a wide range of applications.

[0019] 3. The utility model can break the laminar flow state of the fluid through the blades and the spiral guide rail, change the flow path and direction of the fluid, guide the fluid to rotate along the guide groove on the spiral guide rail, promote the fluid to form turbulence, achieve more efficient heat conduction and lower energy loss, and at the same time increase the impact on the inner wall of the outer casing and the outer wall of the inner casing, reduce the formation and adhesion of scale, and increase the service life of the heat exchanger.

[0020] 4. The utility model arranges a conical cover at the bottom of the inner sleeve and a guide plate in the conical cover, and uses a spiral guide rail to guide the fluid so that the fluid drives the inner sleeve to rotate through the blades. The rotated inner sleeve can guide the fluid in the outer sleeve through the conical cover and the guide plate, thereby improving the circulation efficiency of the heat transfer fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 It is a cross-sectional schematic diagram of the geothermal well heat exchange structure of the utility model;

[0023] Figure 2 It is a schematic diagram of the positional relationship between multiple sets of spiral guide rails and multiple sets of blades of the utility model;

[0024] Figure 3 It is a schematic diagram of the structure of the guide plate inside the conical cover of the utility model;

[0025] Figure 4 It is a schematic diagram of the guide groove structure on the spiral guide rail of the utility model.

[0026] The following are the descriptions of the reference numerals:

[0027] 1. Outer casing; 2. Inner casing; 3. Fixed frame; 4. Spiral guide rail; 5. Guide groove; 6. Blade; 7. Conical cover; 8. Guide plate; 9. Bearing; 10. Inflow end; 11. Outflow end; 12. Cementing material; 13. Geothermal well; 14. Base plate. DETAILED DESCRIPTION

[0028] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be 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 it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0030] The utility model is further described below in conjunction with the accompanying drawings:

[0031] Example 1: Figure 1-Figure 4 As shown, a downhole heat exchanger based on rock and soil energy storage includes an outer sleeve 1 and an inner sleeve 2. A plurality of groups of spiral guide rails 4 are arranged on the inner wall of the outer sleeve 1. The inner sleeve 2 is rotated and inserted into the outer sleeve 1 through a fixing frame 3. A conical cover 7 is fixedly arranged at the end of the inner sleeve 2 located inside the outer sleeve 1. A plurality of guide plates 8 are fixedly arranged on the inner wall of the conical cover 7. A plurality of groups of blades 6 are fixedly arranged on the outer wall of the inner sleeve 2, and each group of blades 6 is correspondingly arranged under each group of spiral guide rails 4.

[0032] Preferably, a bottom plate 14 is provided below the conical cover 7, and the bottom plate 14 is sealed and connected to the outer casing 1, so that leakage of fluid can be prevented and influence on groundwater can be avoided.

[0033] Preferably, the number of each group of spiral guide rails 4 is three, and the three spiral guide rails 4 are evenly fixed on the inner wall of the outer sleeve 1 along the circumference of the outer sleeve 1, and each spiral guide rail 4 is provided with a guide groove 5, and the width of the outflow end 11 on the guide groove 5 does not exceed the width of the outflow end 11. Such a setting can ensure the pitch of the spiral guide rail 4 and the length of each spiral guide rail 4 through the three spiral guide rails 4 set in each group, and can also avoid interference between each group of adjacent spiral guide rails 4.

[0034] Preferably, the number of blades 6 in each group is five. Such an arrangement can ensure that the impact of the fluid flowing through the guide groove 5 on the spiral guide rail 4 on the rotating blades 6 is continuous and balanced, avoiding gaps in the force applied to the blades 6 when the number of blades 6 is the same as the number of spiral grooves or is a multiple of the number of spiral grooves.

[0035] Preferably, a bearing 9 is provided at the connection between the fixing frame 3 and the inner sleeve 2 , and such a configuration can reduce the friction between the inner sleeve 2 and the fixing frame 3 when the inner sleeve 2 rotates, thereby increasing the rotation speed of the inner sleeve 2 .

[0036] The working process of this embodiment is as follows: during operation, after the heat-conducting fluid flows into the gap between the inner sleeve 2 and the outer sleeve 1, a part of the fluid will be blocked by the spiral guide rail 4, causing the fluid to flow along the guide groove 5 on the spiral guide rail 4, destroying the laminar flow state of the fluid. At the same time, the width of the inlet end 10 of the guide groove 5 is greater than the width of the outlet end 11, and the flow velocity of the fluid flowing out of the guide groove 5 will increase. After the fluid flows along the guide groove 5, it will push the inner sleeve 2 to rotate through the baffle plate. After the inner sleeve 2 rotates, it will drive the conical cover 7 to rotate. After the conical cover 7 rotates, the guide plate 8 arranged on the inner wall will generate suction on the fluid in the outer sleeve 1, causing the fluid in the outer sleeve 1 to flow from the outer sleeve 1 into the inner sleeve 2, and finally flow out from the other end of the inner sleeve 2.

[0037] In the utility model, a high thermal conductivity cementing material 12 is filled between the geothermal well 13 and the outer casing 1, so as to facilitate heat exchange between the fluid in the outer casing 1 and the dry hot rock formation, thereby reinforcing the outer casing 1 and improving the heat exchange effect.

[0038] The above is a detailed description of an embodiment of the utility model, but the content is only a preferred embodiment of the utility model and cannot be considered to limit the scope of implementation of the utility model. All equivalent changes and improvements made within the scope of application of the utility model should still fall within the scope of the patent coverage of the utility model.

Claims

1. A downhole heat exchanger based on rock and soil energy storage, characterized in that: The invention comprises an outer sleeve (1) and an inner sleeve (2), wherein the inner wall of the outer sleeve (1) is provided with a plurality of groups of spiral guide rails (4), the inner sleeve (2) is inserted into the outer sleeve (1) by rotation through a fixing frame (3), a conical cover (7) is fixedly provided at the end of the inner sleeve (2) located inside the outer sleeve (1), a plurality of guide plates (8) are fixedly provided on the inner wall of the conical cover (7), and a plurality of groups of blades (6) are fixedly provided on the outer wall of the inner sleeve (2), and each group of blades (6) is correspondingly provided below each group of the spiral guide rails (4).

2. The downhole heat exchanger based on rock and soil energy storage according to claim 1, characterized in that: A bottom plate (14) is provided below the conical cover (7), and the bottom plate (14) is sealedly connected to the outer sleeve (1).

3. The downhole heat exchanger based on rock and soil energy storage according to claim 1, characterized in that: The number of the spiral guide rails (4) in each group is three, and the three spiral guide rails (4) are evenly fixed on the inner wall of the outer sleeve (1) along the circumference of the outer sleeve (1), and each of the spiral guide rails (4) is provided with a guide groove (5), and the width of the outflow end (11) on the guide groove (5) does not exceed the width of the inflow end (10).

4. The downhole heat exchanger based on rock and soil energy storage according to claim 1, characterized in that: The number of blades (6) in each group is five.

5. The downhole heat exchanger based on rock and soil energy storage according to claim 1, characterized in that: A bearing (9) is provided at the connection between the fixing frame (3) and the inner sleeve (2).

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