A buried shallow geothermal spiral rod heat exchange system and a construction method thereof

Abstract

This application relates to the technical field of ground source heat pump heat exchange systems. Addressing the problem of traditional heat exchangers' difficulty in achieving close contact with soil, it proposes a buried shallow geothermal spiral heat exchange system, including a heat pump unit, a heat exchanger buried underground, and a heat exchange terminal located indoors. The heat pump unit is connected to the heat exchanger and the heat exchange terminal via a first circulation pipeline and a second circulation pipeline, respectively. The heat exchanger includes an outer tube with spiral blades coaxially fixed to its outer circumference. An inner tube is coaxially mounted inside the outer tube, and the outer and inner tubes are connected by a main connecting assembly, leaving a gap between them filled with a heat exchange fluid. The inner tube is filled with a circulating working fluid and is also connected to an output pipe and a return pipe. The output and return pipes are connected to the input and output ends of the first circulation pipeline, respectively, to connect the heat exchanger to the heat pump unit. This application effectively improves the heat exchange efficiency between the heat exchanger and the underground soil.

Description

Technical Field

[0001] This application relates to the technical field of ground source heat pump heat exchange systems, and in particular to a buried shallow geothermal spiral bar heat exchange system and its construction method. Background Technology

[0002] Ground source heat pump technology is a renewable energy utilization technology. In related technologies, a ground source heat pump heat exchange system includes a heat exchanger (containing a circulating working fluid) buried underground, a heat pump unit, and heat exchange terminals installed indoors. Both the heat exchanger and the indoor heat exchange terminals are connected to the heat pump unit via circulating pipelines.

[0003] When the local source heat pump heat exchange system is running in heating mode, the heat exchanger exchanges heat with the underground soil, and then the circulating working fluid in the heat exchanger circulates between the heat exchanger and the heat pump unit to achieve heat exchange between the heat exchanger and the heat pump unit. Then, the circulating working fluid in the heat pump unit circulates between the heat pump unit and the heat exchange terminal through the circulation pipeline to achieve heat exchange between the heat pump unit and the heat exchange terminal. Finally, the heat in the underground soil is transferred to the room for people's daily use.

[0004] Regarding the aforementioned technologies, the current installation of heat exchangers typically involves drilling holes in the ground using a drilling rig, placing the heat exchanger inside the holes, and then backfilling the gap between the holes and the heat exchanger with filler material to allow the heat exchanger to better contact the soil and exchange heat. The actual construction is quite complex, and the backfilling process is prone to gaps due to insufficient compaction, which affects the heat exchange between the underground soil and the heat exchanger. Summary of the Invention

[0005] In order to enable the soil to make better contact with the heat exchanger and improve the heat exchange efficiency between the heat exchanger and the soil, this application provides a buried shallow geothermal spiral bar heat exchange system and its construction method.

[0006] This application provides a buried shallow geothermal spiral heat exchange system and its construction method, which adopts the following technical solution:

[0007] A buried shallow geothermal spiral heat exchanger system includes a heat pump unit, a heat exchanger buried underground, and a heat exchange terminal located indoors. The heat pump unit is connected to the heat exchanger and the heat exchange terminal via a first circulation pipeline and a second circulation pipeline, respectively. The heat exchanger includes an outer tube with spiral blades coaxially fixed to its outer circumference. An inner tube is coaxially mounted inside the outer tube, and the outer tube and the inner tube are connected by a main connecting assembly. A gap is left between the outer tube and the inner tube, and the gap between the outer tube and the inner tube is filled with a heat exchange fluid. The inner tube is filled with a circulating working fluid and is also connected to an output pipe and a return pipe. The output pipe and the return pipe are respectively connected to the input end and the output end of the first circulation pipeline to realize the connection between the heat exchanger and the heat pump unit.

[0008] By adopting the above technical solution, with helical blades coaxially fixed to the outer circumference of the outer tube, during the construction of the heat exchanger, the outer tube can be screwed into the ground by a drilling rig, and then the inner tube is coaxially erected inside the outer tube and connected to the outer tube by the main connector. The gap between the outer and inner tubes is filled with heat exchange fluid to enable the soil to exchange heat with the circulating working fluid inside the inner tube. The helical blades fixed to the outer circumference of the outer tube facilitate drilling the outer tube into the ground. On the other hand, after the outer tube is screwed into the ground, the helical blades can achieve a tight connection with the underground soil, which facilitates better heat exchange between the underground soil and the circulating working fluid inside the inner tube. At the same time, the helical blades can also increase the contact area between the heat exchanger and the soil. Compared with the traditional method of backfilling the gap between the heat exchanger and the hole when installing the heat exchanger, this method is more efficient and helps to reduce the situation where the heat exchange efficiency between the underground soil and the heat exchanger is affected by the backfill material not being compacted.

[0009] Preferably, an annular support plate is coaxially fixed to the inner circumference of the top end of the outer tube, and an annular connecting plate is coaxially fixed to the outer circumference of the top end of the inner tube, with the annular connecting plate overlapping the annular support plate.

[0010] By adopting the above technical solution, the inner tube is coaxially mounted inside the outer tube by connecting the annular connecting plate to the annular support plate. This facilitates a uniform gap between the inner and outer tubes, allowing the heat exchange fluid inside the outer tube to evenly envelop the inner tube, thus enabling better heat exchange between the underground soil and the circulating working fluid in the inner tube.

[0011] Preferably, the inner tube has an opening at its top end, and the top of the inner tube is also provided with a sealing cap for closing the opening. The sealing cap is fixed to the annular connecting plate by a number of bolts. The main connecting assembly includes an annular fixing plate coaxially fixed to the outer periphery of the sealing cap. The main connecting assembly also includes a connecting flange coaxially fixed to the outer periphery of the top end of the outer tube. The annular fixing plate is fixed to the connecting flange by a number of bolt and nut pairs.

[0012] By adopting the above scheme, the sealing cap can be detachably connected to the inner tube, facilitating the injection and replacement of the circulating working fluid inside the inner tube. During installation, the inner tube is inserted into the outer tube, and the annular connecting plate is overlapped on the annular support plate, thus achieving coaxial mounting of the inner tube within the outer tube. This allows the heat exchange fluid inside the outer tube to evenly coat the inner tube. The annular fixing plate is secured to the connecting flange using several bolts and nuts, achieving the connection between the outer and inner tubes. This ensures the inner tube is more securely mounted within the outer tube. Simultaneously, the connecting flange facilitates connection between the outer tube and the output end of the drilling rig during installation, allowing the outer tube to be drilled into the underground soil.

[0013] Preferably, the outer pipe is assembled from several sub-pipes, and the ends of adjacent sub-pipes that are close to each other are connected by a sub-connecting assembly; the bottom end of the sub-pipe located at the bottom of the outer pipe is sealed.

[0014] By adopting the above technical solution, it is convenient to add the number of auxiliary pipe fittings according to actual needs to adjust the length of the outer pipe, which is conducive to expanding the application range of the outer pipe.

[0015] Preferably, the secondary connection assembly includes a main flange and a secondary flange coaxially fixed to one end of an adjacent secondary pipe fitting, and the main flange and the secondary flange are connected by a plurality of bolt and nut pairs; the main flange and the secondary flange are respectively coaxially provided with a first annular protrusion and a first annular groove on opposite sides, and the first annular protrusion and the first annular groove are inserted into each other.

[0016] By adopting the above technical solution, when splicing the secondary pipe fittings, the main flange and secondary flange of the adjacent secondary pipe fittings are brought close to each other and abutted against each other. The main flange and secondary flange are connected by bolt and nut pairs, which can realize the assembly of the outer pipe, making the assembly of the outer pipe simpler and more convenient. The setting of the first annular protrusion and the first annular groove facilitates the improvement of the overall strength and sealing of the connection between adjacent secondary pipe fittings.

[0017] Preferably, there is a gap between the bottom end of the inner tube and the bottom end of the outer tube.

[0018] By adopting the above technical solution, it is beneficial to increase the contact area between the inner tube and the heat exchange fluid, which facilitates better heat exchange between the underground soil and the circulating working fluid in the inner tube.

[0019] Preferably, a construction method for a buried shallow geothermal spiral heat exchanger system includes the following steps:

[0020] S1: External pipe installation: Drilling the external pipe into the ground using a drilling rig;

[0021] S2: Inner tube installation: Insert the inner tube into the outer tube and connect the outer tube and the inner tube through the main connection component;

[0022] S3: Inject heat exchange fluid into the gap between the outer tube and the inner tube;

[0023] S4: Connect the inner pipe to the heat pump unit through the first circulation pipe;

[0024] S5: Connect the heat pump unit to the heat exchange terminal through the second circulation pipeline;

[0025] The outer tube is also connected to an injection tube, and the connection between the injection tube and the outer tube is located below the annular support plate. A one-way valve is provided at the end of the injection tube away from the outer tube.

[0026] By adopting the above technical solution, the outer tube is equipped with helical blades on its outer periphery, which facilitates drilling the outer tube into the ground using a drilling rig. At the same time, the helical blades can achieve a tight connection between the outer tube and the soil, which facilitates better heat exchange between the circulating working fluid inside the inner tube and the soil. The helical blades can also increase the contact area between the heat exchanger and the soil. After connecting the outer tube and the inner tube using the main connecting component, the heat exchange fluid is injected into the outer tube through the injection pipe. This facilitates the early injection of heat exchange fluid into the outer tube, which prevents the inner tube from floating due to the heat exchange fluid during installation. This makes the installation and connection of the inner tube simpler and more convenient.

[0027] Preferably, the injection tube is also connected to an air extraction tube, which is located between the outer tube and the one-way valve; the end of the air extraction tube away from the injection tube is also connected to a shut-off valve.

[0028] By adopting the above technical solution, and by setting up the evacuation pipe, in step S3, before injecting the heat exchange liquid into the outer tube through the injection pipe, the inner cavity of the outer tube is first evacuated through the evacuation pipe, and then the heat exchange liquid is injected into the outer tube through the injection pipe, so that the heat exchange liquid can better fill the gap between the outer tube and the inner tube.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] 1. The heat exchanger includes an outer tube with helical blades coaxially fixed on its outer circumference. The helical blades facilitate drilling the outer tube into the ground, and also allow the outer tube to be tightly connected to the soil, enabling better heat exchange between the heat exchanger and the underground soil. Additionally, the helical blades increase the contact area between the heat exchanger and the underground soil.

[0031] 2. An injection pipe is connected to the outer periphery of the top of the outer tube. After the inner tube is inserted into the outer tube and the outer tube and the inner tube are connected by the main connecting assembly, heat exchange fluid is injected into the gap between the outer tube and the inner tube through the injection pipe. This makes it less likely that the heat exchange fluid in the outer tube will cause difficulties in lowering the inner tube during installation.

[0032] 3. The system is equipped with an injection pipe and an extraction pipe. Before injecting the heat exchange liquid into the gap between the outer and inner pipes, the outer pipe is evacuated first through the extraction pipe. This allows the heat exchange liquid to better fill the gap between the inner and outer pipes. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0034] Figure 2 This is a schematic diagram illustrating the overall structure of the heat exchanger.

[0035] Figure 3 This is a schematic diagram illustrating the internal structure of a buried heat exchanger, as shown in the embodiments of this application.

[0036] Figure 4 yes Figure 3 An enlarged schematic diagram of part A in the diagram.

[0037] Figure 5 yes Figure 3 An enlarged schematic diagram of part B in the diagram.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1. Heat exchanger; 11. Outer pipe; 111. Subsidiary pipe fitting; 112. Main flange; 113. Subsidiary flange; 114. First annular protrusion; 115. First annular groove; 116. Annular support plate; 117. Connecting flange; 12. Inner pipe; 121. Sealing cap; 122. Annular connecting plate; 123. Second annular protrusion; 124. Second annular groove; 125. Annular fixing plate; 13. Spiral blade; 14. Output pipe; 15. Return pipe; 2. Heat pump unit; 3. Heat exchange terminal; 4. First circulation pipeline; 5. Second circulation pipeline; 6. Liquid injection pipe; 61. Check valve; 62. Extraction pipe; 63. On / off valve. Detailed Implementation

[0040] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0041] This application discloses a buried shallow geothermal spiral heat exchange system and its construction method.

[0042] A buried shallow geothermal spiral bar heat exchanger system, referring to Figure 1 and Figure 2 It includes a heat pump unit 2, a heat exchanger 1 buried underground, and a heat exchange terminal 3 installed indoors. The heat exchanger 1 is connected to the heat pump unit 2 through a first circulation pipe 4, and the heat exchange terminal 3 is connected to the heat pump unit 2 through a second circulation pipe 5.

[0043] Reference Figure 2 and Figure 3 The heat exchanger 1 includes an outer tube 11 and an inner tube 12 coaxially mounted inside the outer tube 11. A gap is left between the inner circumference of the outer tube 11 and the outer circumference of the inner tube 12, and the gap between the outer tube 11 and the inner tube 12 is filled with heat exchange fluid. A gap is left between the bottom end of the inner tube 12 and the bottom end of the outer tube 11 to facilitate increasing the contact area between the heat exchange fluid and the inner tube 12.

[0044] Reference Figure 2 and Figure 3 The inner tube 12 is filled with circulating medium, and the top of the inner tube 12 is connected to the output pipe 14 and the return pipe 15. The output pipe 14 and the return pipe 15 are respectively connected to the input end and the output end of the first circulation pipeline 4 so that the circulating working medium in the heat exchanger 1 can circulate between the heat exchanger 1 and the heat pump unit 2.

[0045] In this embodiment, both the outer tube 11 and the inner tube 12 are made of metal, and the circulating medium in the inner tube 12 is a low-boiling-point working fluid. Both the first circulation pipeline 4 and the second circulation pipeline 5 are equipped with working fluid pumps to achieve the circulation of the working fluid. Heat exchanger 1 and heat pump unit 2 exchanging heat using a low-boiling-point working fluid is existing technology and will not be described further. During actual operation, the low-boiling-point working fluid in the inner tube 12 exchanges heat with the underground soil to form a high-temperature gaseous working fluid. This gaseous working fluid enters the first circulation pipeline 4 through the output pipe 14, exchanges heat with the heat pump unit 2, and then re-liquefies to form a low-temperature liquid working fluid. This liquid working fluid is then pumped back into the inner tube 12 by the working fluid pump on the first circulation pipeline 4, causing the circulating working fluid in the heat exchanger 1 to circulate repeatedly between the heat exchanger 1 and the heat pump unit 2, thereby achieving heat exchange between the two. In actual use, a vent pipe can be installed on the inner tube 12, and a pressure gauge and a pressure relief valve can be installed on the vent pipe to monitor and adjust the air pressure inside the inner tube 12 in a timely manner.

[0046] Reference Figure 3 and Figure 4 The outer tube 11 is coaxially fixed with a spiral blade 13. The spiral blade 13 facilitates drilling the outer tube 11 into the ground with a drilling rig. At the same time, the spiral blade 13 can achieve close contact between the outer tube 11 and the underground soil, which facilitates better heat exchange between the underground soil and the circulating working fluid in the inner tube 12. The spiral blade 13 can also increase the contact area between the outer tube 11 and the soil, which facilitates better heat exchange between the heat exchanger 1 and the soil.

[0047] Reference Figure 3 and Figure 4The outer pipe 11 is assembled from several secondary pipe fittings 111. The bottom end of the secondary pipe fittings 111 located at the bottom of the outer pipe 11 is sealed and has a sharp point, which facilitates the drilling of the outer pipe 11 into the ground by a drilling rig. Adjacent secondary pipe fittings 111 are connected by secondary connecting assemblies. The secondary connecting assemblies include a main flange 112 and a secondary flange 113 coaxially fixed at one end of the adjacent secondary pipe fittings 111. The main flange 112 and the secondary flange 113 are connected by several bolt and nut pairs to realize the assembly of adjacent secondary pipe fittings 111.

[0048] The main flange 112 and the secondary flange 113 are respectively coaxially fixed with a first annular protrusion 114 and a first annular groove 115 on the side close to each other. The first annular protrusion 114 and the first annular groove 115 are inserted and matched, which helps to improve the connection integrity and sealing between adjacent secondary pipe fittings 111.

[0049] Reference Figure 3 and Figure 5 An annular support plate 116 is coaxially fixed to the inner circumference of the top end of the outer tube 11, and an annular connecting plate 122 is coaxially fixed to the outer circumference of the top end of the inner tube 12, with the annular connecting plate 122 overlapping the annular support plate 116, thereby enabling the inner tube 12 to be coaxially mounted inside the outer tube 11.

[0050] The inner tube 12 has an opening at its top, and a sealing cap 121 for closing the opening is also provided at the top of the inner tube 12. The output pipe 14 and the return pipe 15 are both located on the sealing cap 121. The sealing cap 121 is fixed to the annular connecting plate 122 by several bolts, thereby closing the opening at the top of the inner tube 12. This arrangement facilitates the filling and replacement of the circulating medium.

[0051] The second annular protrusion 123 is coaxially fixed on the lower surface of the sealing cover 121, and the second annular groove 124 is coaxially provided on the upper surface of the annular connecting plate 122. The second annular protrusion 123 and the second annular groove 124 are inserted and matched, which helps to improve the sealing performance between the sealing cover 121 and the inner tube 12.

[0052] The main connection assembly includes a connecting flange 117 coaxially fixed to the outer periphery of the top end of the outer tube 11 and an annular fixing plate 125 coaxially fixed to the outer periphery of the sealing cover 121. The annular fixing plate 125 is fixed to the connecting flange 117 by several spiral nuts, thereby fixing the inner tube 12 to the outer tube 11 and restricting the displacement of the inner tube 12. At the same time, the setting of the connecting flange 117 facilitates the connection of the outer tube 11 to the output end of the drilling rig, thereby facilitating the drilling of the outer tube 11 into the ground by the drilling rig.

[0053] A construction method for a buried shallow geothermal spiral heat exchanger system includes the following steps:

[0054] S1: Installation of outer pipe 11: Drill the outer pipe 11 into the ground using a drilling rig; during actual construction, connect the connecting flange 117 of the outer pipe 11 to the output end of the drilling rig. After the outer pipe 11 is drilled to the specified depth, disconnect the connection between the drilling rig and the connecting flange 117 and remove the drilling rig.

[0055] S2: Inner tube 12 installation: Insert the inner tube 12 into the outer tube 11 and connect the outer tube 11 and the inner tube 12 through the main connecting assembly; the specific operation steps are as follows: move the inner tube 12 and insert the inner tube 12 into the outer tube 11 until the annular connecting plate 122 overlaps on the annular support plate 116, and fix the annular fixing plate 125 and the connecting flange 117 at the top of the outer tube 11 through the spiral nut pair to realize the installation and fixation of the inner tube 12.

[0056] S3: Inject heat exchange fluid into the gap between the outer tube 11 and the inner tube 12.

[0057] The outer tube 11 is also connected to the outer periphery of the top end of the outer tube 11. A one-way valve 61 is installed at the end of the injection pipe 6 away from the outer tube 11. After the inner tube 12 is connected to the outer tube 11, heat exchange liquid is injected into the outer tube 11 and the inner tube 12 through the injection pipe 6. This helps to reduce the situation where the inner tube 12 floats when it is installed due to the premature injection of heat exchange liquid.

[0058] The injection pipe 6 is also connected to the vacuum pipe 62. The vacuum pipe 62 is located between the one-way valve 61 and the outer pipe 11. The end of the vacuum pipe 62 away from the injection pipe 6 is also connected to the on / off valve 63. By setting the vacuum pipe 62, before injecting the heat exchange liquid into the outer pipe 11, the outer pipe 11 is first evacuated through the vacuum pipe 62, and then the heat exchange liquid is injected into the outer pipe 11 through the injection pipe 6, so that the heat exchange liquid can better fill the gap between the inner pipe 12 and the outer pipe 11.

[0059] S4: Connect the output pipe 14 and return pipe 15 on the inner pipe 12 to the heat pump unit 2 through the first circulation pipe 4;

[0060] S5: Connect the heat pump unit 2 to the heat exchange terminal 3 through the second circulation pipeline 5.

[0061] The outer tube 11 is coaxially fixed with spiral blades 13 on its outer periphery. When installing the heat exchanger 1, it is convenient to drill the outer tube 11 into the ground with a drilling rig. At the same time, the outer tube 11 can make closer contact with the underground soil through the spiral blades 13, which is beneficial to improving the heat exchange efficiency between the heat exchanger 1 and the underground soil.

[0062] After the outer tube 11 and the inner tube 12 are connected by the main connecting assembly, heat exchange fluid is injected into the gap between the outer tube 11 and the inner tube 12 through the injection pipe 6. This helps to reduce the possibility of the inner tube 12 floating due to the premature injection of heat exchange fluid. The injection pipe 6 is also connected to the evacuation pipe 62. Before injecting heat exchange fluid into the outer tube 11, the evacuation pipe 62 is used to evacuate the gap between the outer tube 11 and the inner tube 12, so that the heat exchange fluid can better fill the gap between the outer tube 11 and the inner tube 12 in the future.

[0063] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A buried shallow geothermal spiral heat exchange system, comprising a heat pump unit (2), a heat exchanger (1) buried underground, and a heat exchange terminal (3) located indoors; the heat pump unit (2) is connected to the heat exchanger (1) and the heat exchange terminal (3) respectively through a first circulation pipeline (4) and a second circulation pipeline (5); characterized in that: The heat exchanger (1) includes an outer tube (11) with a spiral blade (13) coaxially fixed on its outer circumference; an inner tube (12) is coaxially mounted inside the outer tube (11), and the outer tube (11) and the inner tube (12) are connected by a main connecting assembly. A gap is left between the outer tube (11) and the inner tube (12), and the gap between the outer tube (11) and the inner tube (12) is filled with heat exchange fluid; the inner tube (12) is filled with circulating working fluid, and the inner tube (12) is also connected to an output pipe (14) and a return pipe (15). The output pipe (14) and the return pipe (15) are respectively connected to the input end and the output end of the first circulation pipeline (4) to realize the connection between the heat exchanger (1) and the heat pump unit (2).

2. The buried shallow geothermal spiral heat exchanger system according to claim 1, characterized in that: An annular support plate (116) is coaxially fixed to the inner circumference of the top end of the outer tube (11), and an annular connecting plate (122) is coaxially fixed to the outer circumference of the top end of the inner tube (12). The annular connecting plate (122) overlaps the annular support plate (116).

3. The buried shallow geothermal spiral heat exchanger system according to claim 2, characterized in that: The inner tube (12) has an opening at its top end, and the top of the inner tube (12) is also provided with a sealing cap (121) for closing the opening. The sealing cap (121) is fixed to the annular connecting plate (122) by several bolts. The main connecting assembly includes an annular fixing plate (125) coaxially fixed to the outer periphery of the sealing cap (121). The main connecting assembly also includes a connecting flange (117) coaxially fixed to the outer periphery of the top end of the outer tube (11). The annular fixing plate (125) is fixed to the connecting flange (117) by several bolt and nut pairs.

4. The buried shallow geothermal spiral heat exchanger system according to claim 1, characterized in that: The outer tube (11) is spliced ​​together from several sub-pipes (111), and the ends of adjacent sub-pipes (111) that are close to each other are connected by a sub-connecting assembly; the bottom end of the sub-pipe (111) located at the bottom of the outer tube (11) is sealed.

5. A buried shallow geothermal spiral heat exchanger system according to claim 4, characterized in that: The secondary connection assembly includes a main flange (112) and a secondary flange (113) coaxially fixed to one end of an adjacent secondary pipe fitting (111), which are close to each other. The main flange (112) and the secondary flange (113) are connected by a plurality of bolts and nuts. The main flange (112) and the secondary flange (113) are respectively coaxially provided with a first annular protrusion (114) and a first annular groove (115) on opposite sides, and the first annular protrusion (114) and the first annular groove (115) are inserted into each other.

6. A buried shallow geothermal spiral heat exchanger system according to claim 5, characterized in that: There is a gap between the bottom end of the inner tube (12) and the bottom end of the outer tube (11).

7. A construction method for a buried shallow geothermal spiral heat exchanger system as described in any one of claims 1 to 6, characterized in that: Includes the following steps: S1: Installation of outer pipe (11): Drill the outer pipe (11) into the ground using a drilling rig; S2: Inner tube (12) installation: Insert the inner tube (12) into the outer tube (11) and connect the outer tube (11) and the inner tube (12) through the main connection assembly; S3: Inject heat exchange fluid into the gap between the outer tube (11) and the inner tube (12); S4: Connect the inner pipe (12) to the heat pump unit (2) through the first circulation pipe (4); S5: Connect the heat pump unit (2) to the heat exchange terminal (3) through the second circulation pipeline (5); The outer tube (11) is also connected to an injection tube (6). The connection between the injection tube (6) and the outer tube (11) is located below the annular support plate (116). A one-way valve (61) is provided at the end of the injection tube (6) away from the outer tube (11).

8. The construction method of a buried shallow geothermal spiral heat exchanger system according to claim 7, characterized in that: The injection tube (6) is also connected to an air extraction tube (62), which is located between the outer tube (11) and the one-way valve (61); the end of the air extraction tube (62) away from the injection tube (6) is also connected to a shut-off valve (63).

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