A coaxial counter-rotating helical fin heat exchanger

Abstract

The present application relates to a kind of heat exchanger with coaxial reverse spiral fin, including heat pump unit, driving device and burying in rock-soil body underground heat exchanger, underground heat exchanger is connected with heat pump unit and forms closed loop;Heat pump unit includes compressor, condenser and expansion valve;Driving device can drive inner tube rotation, inner tube is also equipped with coaxial reverse device, can change the rotation direction of upper and lower inner tube, realize the reverse rotation between adjacent inner tube;Underground heat exchanger includes outer tube, backfill material, circulating working medium and inner tube fixing device;The working medium of inner tube outer wall space can enter heat pump unit through water pipe I in inner tube interior.This application increases the heat exchange area by installing driving device on the upper part of inner tube and adding bevel gear on inner tube, reduces heat transfer loss, improves the stability of heat exchanger;By installing outer sleeve bearing on inner tube and connecting support frame on inner wall of outer tube, the relative position of inner tube is fixed, the stability of heat exchanger is improved, and the heat exchange efficiency is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of deep coaxial sleeve geothermal heating technology, specifically relating to a spiral fin heat exchanger that utilizes coaxial reversal. Background Technology

[0002] Geothermal energy, as a new type of clean energy, has become the most promising renewable energy source after hydropower and biomass energy due to its wide distribution and lack of spatial limitations.

[0003] Medium-deep coaxial borehole heat exchangers utilize a vertically placed inner tube (insulated tube) in a coaxial configuration for closed-loop fluid circulation, extracting heat from the rock and soil mass via heat conduction, achieving heat extraction without water extraction. However, traditional medium-deep coaxial geothermal systems suffer from limited heat exchange areas, often exhibiting problems such as low heat extraction temperatures, significant heat loss, and unstable heat exchange efficiency, resulting in low efficiency. Therefore, there is an urgent need to develop a spiral finned heat exchanger utilizing coaxial reversal to effectively address these issues. Summary of the Invention

[0004] The purpose of this invention is to provide a coaxial reverse-rotating spiral fin heat exchanger to solve the problems of low efficiency in medium-deep coaxial heat exchange systems caused by factors such as low heat extraction temperature, severe heat loss, and unstable heat exchange efficiency.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A coaxially rotating spiral fin heat exchanger includes a heat pump unit 14, a drive device 18, and an underground heat exchanger 19 buried in the rock and soil mass 1; the underground heat exchanger 19 is connected to the heat pump unit 14 to form a closed loop.

[0007] The heat pump unit 14 includes a compressor 15, a condenser 16, and an expansion valve 17.

[0008] The drive device 18 is connected to the outlet of the inner tube 4 and can drive the inner tube 4 to rotate. The outer wall of the inner tube 4 is provided with spiral fins 6. The outer wall of the inner tube 4 is also equipped with a coaxial reversing device 26 composed of three connected bevel gears. The coaxial reversing device 26 can change the rotation direction of the upper and lower inner tubes 4 and realize the reverse rotation between adjacent inner tubes 4.

[0009] The underground heat exchanger 19 includes an outer pipe 3, a backfill material 2 between the soil and rock mass 1 and the outer pipe 3, a circulating working fluid 25 between the outer pipe 3 and the inner pipe 4, a coaxial reversal device 26, and multiple inner pipe fixing devices 27 located between the inner pipe 4 and the outer pipe 3.

[0010] The outlet of the inner pipe 4 is connected to the water pipe sleeve 24, and a drive device 18 is installed on the water pipe sleeve 24. The outlet of the water pipe sleeve 24 is connected to water pipe I 20. Water pipe I 20 is connected to the compressor 15. The compressor 15 is connected to the condenser 16 through water pipe II 21. The condenser 16 is connected to the expansion valve 17 through water pipe III 22. The expansion valve 17 is connected to water pipe IV 23. Water pipe IV 23 is connected to the water pipe sleeve 24, forming a closed circulation space. The working fluid 25 in the outer wall space of the inner pipe 4 can enter the heat pump unit 14 through the inner pipe 4 via water pipe I 20.

[0011] Furthermore, the outer tube 3 is made of carbon fiber material with high thermal conductivity, and the inner tube 4 is made of polyurethane material with low thermal conductivity.

[0012] Furthermore, the outer pipe 3 is fixed to the rock and soil body 1 by filling the gap with backfill material 2; the inner pipe 4 and the outer pipe 3 are coaxial sleeves, the inner pipe 4 is embedded inside the outer pipe 3, the space between the inner wall of the outer pipe 3 and the outer wall of the inner pipe 4 is connected by a water pipe sleeve 24 for inputting working fluid 25, the internal space of the inner pipe 4 is connected by a water pipe sleeve 24 for outputting working fluid, and the bottom of the inner pipe 4 is slightly lower than the outer pipe 3.

[0013] Furthermore, the spiral fins 6 are welded to the outer wall of the inner tube 4 at high temperature, and a driving device 18 is provided at the connection between the top of the inner tube 4 and the water pipe sleeve 24; the coaxial reversing device 26 can be installed between different inner tubes 4, and the driving device 18 can rotate at different speeds and drive the spiral fins 6.

[0014] Furthermore, the three bevel gears are an upper bevel gear 9, a vertical bevel gear 31, and a lower bevel gear 32. The driving device 18 drives the upper inner tube 4 to rotate clockwise, the upper inner tube 4 drives the upper bevel gear 9 to rotate clockwise, the upper bevel gear 9 drives the vertical bevel gear 31 to rotate clockwise, the vertical bevel gear 31 drives the lower bevel gear 32 to rotate counterclockwise, and the lower bevel gear 32 drives the lower inner tube 4 to rotate counterclockwise.

[0015] Furthermore, the inner tube 4 has a threaded inner tube inner wall spiral section 5 at its inner wall port; the lower bevel gear 9, the upper bevel gear 31 and the vertical bevel gear 32 are hollow inside, and the inner wall of the bevel gear is provided with bevel gear inner wall thread 10, and the inner tube 4 and the bevel gear are connected by threads.

[0016] Furthermore, an inner tube fixing device 27 is installed between every two inner tubes 4. The inner tube fixing device 27 is simultaneously connected to the outer wall of the inner tube 4, the inner wall of the outer tube 3, and the vertical bevel gear 32.

[0017] Furthermore, the inner tube fixing device 27 consists of a fixing nut 7, a bearing 11, and a support rod 13. One end of the support rod 13 is welded to the outer wall of the bearing 11 at high temperature. A total of 4 support rods 13 are welded to the outer wall of the bearing 11 at equal intervals. Among them, the distance between 3 straight support rods 13 and the inner wall of the outer tube 3 is equal, and the other I-shaped support rod 8 is slightly shorter, but longer than the vertical bevel gear 32.

[0018] Furthermore, the inner tube fixing device 27 of the upper inner tube 4 and the inner tube fixing device 27 of the lower inner tube are welded together by the fixing nut 7 at the end of the I-shaped support rod 8, and the vertical bevel gear 32 is fixed by the nut at the end of the I-shaped support rod 8, together forming a complete fixing device to prevent the inner tube 4 from shifting and generating centrifugal rotation.

[0019] Furthermore, the bearing 11 is composed of a ball 12, an outer ring 28, an inner ring 29, and a cage 30. The outer ring 28 is connected to the support rod 13, the inner ring 29 is connected to the outer wall of the inner tube 4, and the cage 30 fixes the ball 12 between the inner and outer rings. When the inner tube 4 rotates, the bearing keeps the inner ring 29 rotating while the outer ring 28 remains stationary, thus serving as a connecting and fixing device.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. The present invention increases the heat exchange area by installing a driving device on the upper part of the inner tube to drive the inner tube with spiral fins to rotate.

[0022] 2. By installing an outer bearing on the inner tube and a support frame connecting to the inner wall of the outer tube, the bearing keeps the outside of the bearing and the support frame stationary when the inner tube rotates. The two upper and lower bearings and six support frames fix the relative position of the inner tube, improving the stability of the heat exchanger and enhancing the heat exchange efficiency.

[0023] 3. By setting threads at the inner wall end of the inner tube and connecting them with the internal threads of the bevel gear, each section of the upper and lower sleeve is fixed, simplifying the installation process of the sleeve and improving operational efficiency.

[0024] 4. By adding bevel gears to the inner tube, the reverse rotation between every two sleeves is achieved under the drive of the drive device, which further increases the heat exchange area, reduces heat transfer loss, and improves the stability of heat exchange efficiency. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1This is a schematic diagram of the overall structure of the coaxial reverse-rotating spiral fin heat exchanger of the present invention.

[0027] Figure 2 This is a schematic diagram of the inner tube of the spiral fin;

[0028] Figure 3 This is a top view of the inner tube of the spiral fin;

[0029] Figure 4 This is a top view of a bevel gear;

[0030] Figure 5 This is a top view of the bearing.

[0031] In the diagram: 1. Soil and rock mass; 2. Backfill material; 3. Outer pipe; 4. Inner pipe; 5. Spiral section of inner wall of inner pipe; 6. Spiral fins; 7. Fixing nut; 8. I-shaped support rod; 9. Upper bevel gear; 10. Thread on inner wall of bevel gear; 11. Bearing; 12. Ball; 13. Support rod; 14. Heat pump unit; 15. Compressor; 16. Condenser; 17. Expansion valve; 18. Drive device; 19. Underground heat exchanger; 20. Water pipe I; 21. Water pipe II; 22. Water pipe III; 23. Water pipe IV; 24. Water pipe sleeve; 25. Working fluid; 26. Coaxial reversing device; 27. Inner pipe fixing device; 28. Outer ring; 29. ​​Inner ring; 30. Cage; 31. Vertical bevel gear; 32. Lower bevel gear. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments:

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0034] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] like Figures 1-5 As shown, the present invention utilizes a coaxially rotating spiral fin heat exchanger, including a heat pump unit 14, a drive device 18, and an underground heat exchanger 19 buried in the rock and soil mass 1.

[0036] The heat pump unit 14 includes a compressor 15, a condenser 16, and an expansion valve 17.

[0037] The drive device 18 is connected to the outlet of the inner tube 4.

[0038] The underground heat exchanger 19 includes an outer pipe 3, backfill material 2 between the soil and rock mass 1 and the outer pipe 3, a circulating working fluid 25 between the outer pipe 3 and the inner pipe 4, a coaxial reversing device 26, and an inner pipe fixing device 27.

[0039] Specifically, the underground heat exchanger 19, buried in the soil and rock mass 1, is connected to the heat pump unit 14 to form a closed loop. The outlet of the inner pipe 4 is connected to the water pipe sleeve 24, and a drive device 18 is installed on the water pipe sleeve 24. The outlet of the water pipe sleeve 24 is connected to water pipe I 20, which is connected to the compressor 15. The compressor 15 is connected to the condenser 16 via water pipe II 21, and the condenser 16 is connected to the expansion valve 17 via water pipe III 22. The expansion valve 17 is connected to water pipe IV 23, which is connected to the water pipe sleeve 24, forming a closed circulation space.

[0040] The outer pipe 3 is fixed to the soil mass 1 by filling the gap with backfill material 2. The inner pipe 4 and the outer pipe 3 are coaxial sleeves. The inner pipe 4 is embedded inside the outer pipe 3. The space between the inner wall of the outer pipe 3 and the outer wall of the inner pipe 4 is connected by a water pipe sleeve 24 for inputting the working fluid 25. The space inside the inner pipe 4 is connected by a water pipe sleeve 24 for outputting the working fluid. The bottom of the inner pipe 4 is slightly lower than the outer pipe 3 so that the working fluid 25 in the space of the outer wall of the inner pipe 4 can enter the heat pump unit 14 through the water pipe I 20 inside the inner pipe 4.

[0041] Specifically, the outer tube 3 is made of carbon fiber material with high thermal conductivity, which improves heat transfer efficiency while ensuring the strength and stability of the outer tube; the inner tube 4 is made of polyurethane material with low thermal conductivity, which isolates heat transfer while ensuring the wear resistance of the inner tube.

[0042] The outer wall of the inner tube 4 is equipped with spiral fins 6, which are welded to the outer wall of the inner tube 4 at high temperature. A driving device 18 is provided at the connection between the top of the inner tube 4 and the water pipe sleeve 24 to drive the inner tube 4 to rotate.

[0043] The outer wall of the inner tube 4 is fitted with an upper bevel gear 9, a vertical bevel gear 31, and a lower bevel gear 32. These bevel gears are made of aluminum alloy, and the three connected bevel gears form a coaxial reversing device 26. The driving device 18 drives the upper inner tube 4 to rotate clockwise, which in turn drives the upper bevel gear 9 to rotate clockwise. The upper bevel gear 9 then drives the vertical bevel gear 31 to rotate clockwise, which in turn drives the lower bevel gear 32 to rotate counterclockwise. The lower bevel gear 32 then drives the lower inner tube 4 to rotate counterclockwise. The coaxial reversing device 26 changes the rotation direction of the upper and lower inner tubes 4, achieving reverse rotation between adjacent inner tubes 4.

[0044] Specifically, the inner tube 4 has a threaded inner tube spiral section 5 at its inner wall port. The lower bevel gear 32, the upper bevel gear 9, and the vertical bevel gear 31 are hollow inside, and the inner wall of the bevel gear is provided with bevel gear inner wall thread 10. The inner tube 4 and the bevel gear are connected by threads. The rotation of the inner tube 4 can ensure that the inner tube 4 and the bevel gear are always stably and tightly connected, preventing the inner tube 4 from falling off.

[0045] There are multiple inner tube fixing devices 27 between the inner tube 4 and the outer tube 3. A set of inner tube fixing devices 27 is installed between every two inner tubes 4. The inner tube fixing devices 27 are simultaneously connected to the outer wall of the inner tube 4, the inner wall of the outer tube 3, and the vertical bevel gear 32.

[0046] Specifically, the inner tube fixing device 27 consists of a fixing nut 7, a bearing 11, and a support rod 13. One end of the support rod 13 is welded to the outer wall of the bearing 11 at high temperature. A total of four support rods 13 are welded to the outer wall of the bearing 11 at equal intervals. Among them, three straight support rods 13 are equidistant from the inner wall of the outer tube 3, and the other I-shaped support rod 8 is slightly shorter but longer than the vertical bevel gear 32.

[0047] Specifically, the bearing 11 consists of a ball 12, an outer ring 28, an inner ring 29, and a cage 30. The outer ring 28 is connected to the support rod 13, the inner ring 29 is connected to the outer wall of the inner tube 4, and the cage 30 fixes the ball 12 between the inner and outer rings. When the inner tube 4 rotates, the bearing keeps the inner ring 29 rotating while the outer ring 28 remains stationary, thus serving as a connecting and fixing device.

[0048] Specifically, the inner tube fixing device 27 of the upper inner tube 4 and the inner tube fixing device 27 of the lower inner tube are welded together by the fixing nut 7 at the end of the I-shaped support rod 8, and the vertical bevel gear 32 is fixed by the nut at the end of the I-shaped support rod 8, together forming a complete fixing device to prevent the inner tube 4 from shifting and generating centrifugal rotation, and to ensure the stable operation of the heat exchanger.

[0049] In this embodiment, the coaxial reversing device 26 can be installed between different inner tubes 4, and the driving device 18 can rotate at different speeds and drive the spiral fins 6 to generate eddies, enhance heat transfer, and improve heat transfer efficiency.

[0050] This invention employs a reversible spiral finned underground heat exchanger. By using a coaxial reversing device 26, the inner tube 4 can rotate in different directions in each section, effectively improving the stability of the heat exchange capacity and efficiency of the medium-deep coaxial casing. The spiral section 5 on the inner wall of the inner tube and the bevel gear spiral design effectively prevent the inner tube 4 from detaching and improve the installation efficiency of the casing. The addition of an inner tube fixing device 27 to the outside of the inner tube 4 solves the problems of inner tube 4 misalignment and centrifugal rotation, ensuring the stable operation of the heat exchanger. These technological innovations and system improvements contribute to improving the performance and economy of geothermal resources.

[0051] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A spiral fin heat exchanger utilizing coaxial reversal, characterized in that: It includes a heat pump unit (14), a drive unit (18), and an underground heat exchanger (19) buried in the rock and soil (1); the underground heat exchanger (19) is connected to the heat pump unit (14) to form a closed loop; The heat pump unit (14) includes a compressor (15), a condenser (16), and an expansion valve (17). The drive device (18) is connected to the outlet of the inner tube (4) and can drive the inner tube (4) to rotate. The outer wall of the inner tube (4) is provided with spiral fins (6). The outer wall of the inner tube (4) is also equipped with a coaxial reversing device (26) consisting of three connected bevel gears. The coaxial reversing device (26) can change the rotation direction of the upper and lower inner tubes (4) and realize the reverse rotation between adjacent inner tubes (4). The underground heat exchanger (19) includes an outer pipe (3), backfill material (2) between the soil and rock mass (1) and the outer pipe (3), circulating working fluid (25) between the outer pipe (3) and the inner pipe (4), a coaxial reversing device (26), and multiple inner pipe fixing devices (27) located between the inner pipe (4) and the outer pipe (3). The outlet of the inner pipe (4) is connected to the water pipe sleeve (24), and a drive device (18) is installed on the water pipe sleeve (24). The outlet of the water pipe sleeve (24) is connected to water pipe I (20). Water pipe I (20) is connected to the compressor (15). The compressor (15) is connected to the condenser (16) through water pipe II (21). The condenser (16) is connected to the expansion valve (17) through water pipe III (22). The expansion valve (17) is connected to water pipe IV (23). Water pipe IV (23) is connected to the water pipe sleeve (24), forming a closed circulation space. The working fluid (25) in the outer wall space of the inner pipe (4) can enter the heat pump unit (14) through the inner pipe (4) via water pipe I (20). The underground heat exchanger (19) buried in the rock and soil (1) is connected to the heat pump unit (14) to form a closed loop; the outer wall of the inner tube (4) is equipped with an upper bevel gear (9), a vertical bevel gear (31) and a lower bevel gear (32).

2. A coaxially rotating spiral fin heat exchanger according to claim 1, characterized in that: The outer tube (3) is made of carbon fiber material with high thermal conductivity, and the inner tube (4) is made of polyurethane material with low thermal conductivity.

3. A coaxially rotating spiral fin heat exchanger according to claim 1, characterized in that: The outer pipe (3) is fixed to the rock and soil body (1) by filling the gap with backfill material (2); the inner pipe (4) and the outer pipe (3) are coaxial sleeves, the inner pipe (4) is embedded inside the outer pipe (3), the space between the inner wall of the outer pipe (3) and the outer wall of the inner pipe (4) is connected by a water pipe sleeve (24) for inputting working medium (25), the internal space of the inner pipe (4) is connected by a water pipe sleeve (24) for outputting working medium, and the bottom of the inner pipe (4) is slightly lower than the outer pipe (3).

4. A coaxially rotating spiral fin heat exchanger according to claim 1, characterized in that: The spiral fins (6) are welded to the outer wall of the inner tube (4) at high temperature. A drive device (18) is provided at the connection between the top of the inner tube (4) and the water pipe sleeve (24). The coaxial reversing device (26) is installed between different inner tubes (4), and the drive device (18) rotates at different speeds and drives the spiral fins (6).

5. A spiral fin heat exchanger utilizing coaxial reversal as described in claim 1, characterized in that: The three bevel gears are an upper bevel gear (9), a vertical bevel gear (31), and a lower bevel gear (32). The driving device (18) drives the upper inner tube (4) to rotate clockwise, the upper inner tube (4) drives the upper bevel gear (9) to rotate clockwise, the upper bevel gear (9) drives the vertical bevel gear (31) to rotate clockwise, the vertical bevel gear (31) drives the lower bevel gear (32) to rotate counterclockwise, and the lower bevel gear (32) drives the lower inner tube (4) to rotate counterclockwise.

6. A coaxially rotating spiral fin heat exchanger according to claim 5, characterized in that: The inner tube (4) has a threaded inner tube inner wall spiral section (5) at the inner wall port; the upper bevel gear (9), the vertical bevel gear (31) and the lower bevel gear (32) are hollow inside, and the inner wall of the bevel gear is provided with bevel gear inner wall thread (10). The inner tube (4) and the bevel gear are connected by threads.

7. A spiral fin heat exchanger utilizing coaxial reversal as described in claim 5, characterized in that: An inner tube fixing device (27) is installed between every two inner tubes (4). The inner tube fixing device (27) is simultaneously connected to the outer wall of the inner tube (4), the inner wall of the outer tube (3), and the vertical bevel gear (31).

8. A coaxially rotating spiral fin heat exchanger according to claim 7, characterized in that: The inner tube fixing device (27) consists of a fixing nut (7), a bearing (11) and a support rod (13). One end of the support rod (13) is welded to the outer wall of the bearing (11) at high temperature. A total of 4 support rods (13) are welded to the outer wall of the bearing (11) at equal intervals. Among them, the distance between 3 straight support rods (13) and the inner wall of the outer tube (3) is equal. The other I-shaped support rod (8) is slightly shorter, but longer than the vertical bevel gear (31).

9. A spiral fin heat exchanger utilizing coaxial reversal as described in claim 8, characterized in that: The inner tube fixing device (27) of the upper inner tube (4) and the inner tube fixing device (27) of the lower inner tube are welded together by the fixing nut (7) at the end of the I-shaped support rod (8). The vertical bevel gear (31) is fixed by the nut at the end of the I-shaped support rod (8), together forming a complete fixing device to prevent the inner tube (4) from shifting and generating centrifugal rotation.

10. A coaxially rotating spiral fin heat exchanger according to claim 8, characterized in that: The bearing (11) consists of a ball (12), an outer ring (28), an inner ring (29), and a cage (30). The outer ring (28) is connected to the support rod (13), the inner ring (29) is connected to the outer wall of the inner tube (4), and the cage (30) fixes the ball (12) between the inner and outer rings. When the inner tube (4) rotates, the bearing keeps the inner ring (29) rotating while the outer ring (28) remains stationary, thus serving as a connecting and fixing device.

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