Single-well heat removal system

Abstract

The invention provides a single well heat extraction system which comprises a wellbay, a heat extraction device and a heat extraction device. The ground device is arranged on the wellbay and is provided with a first water inlet pipe and a first water return pipe which are communicated with an external water environment; the heat exchange device is arranged in the geothermal well and comprises a heat exchanger, the heat exchanger is provided with a circulation side and a heat exchange side, the circulation side is communicated with the first water inlet pipe and the first water return pipe, and the heat exchange side is communicated with a geothermal environment, so that geothermal water exchanges heat with the circulation side in the geothermal well; and the submersible pump is arranged below the heat exchanger, is communicated with the heat exchange side and is configured to pump the geothermal water to the heat exchange side.

Description

Technical Field

[0001] At least one embodiment of the present disclosure relates to the field of geothermal heat extraction technology, and in particular, to a single-well heat extraction system. Background Art

[0002] As a clean and renewable energy, geothermal energy is widely used in heating, power generation, hot springs and agricultural greenhouses. Geothermal energy is mostly exploited through geothermal wells, which generally include extraction wells and reinjection wells. As the name implies, extraction wells are suitable for extracting geothermal water to exchange heat with the external water environment on the well, while reinjection wells are used to re-inject low-temperature geothermal water into the ground after heat exchange.

[0003] In order to reduce the floor space occupied by geothermal wells, some geothermal wells are currently configured as a single well structure, that is, the extraction well and the reinjection well are integrated into one wellhead. In addition, with the emphasis on the recycling of geothermal energy and the requirement for groundwater balance, in order to prevent environmental problems such as ground subsidence and water source depletion caused by excessive groundwater extraction, and to maintain the pressure of underground heat reservoirs to maintain the sustainable use of geothermal resources, corresponding requirements are now made for the reinjection volume of geothermal wells. For example, the reinjection volume of geothermal tail water in the same layer of geothermal wells must reach more than 95% (even equal reinjection is required, that is, under ideal conditions, the reinjection volume of geothermal tail water should be equal to or slightly greater than the extraction volume).

[0004] Therefore, how to provide a single-well heat extraction system that can effectively increase the reinjection volume of geothermal water has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve at least one of the above and other technical problems in the prior art, the present disclosure provides a single-well heat extraction system to increase the reinjection volume of geothermal water.

[0006] The present disclosure provides a single-well heat extraction system, comprising: a well platform, arranged at the wellhead of a geothermal well; an above-the-well device, arranged on the well platform, having a first water inlet pipe and a first water return pipe connected to an external water use environment; a heat exchange device, arranged in the geothermal well, comprising: a heat exchanger, having a circulation side and a heat exchange side, the circulation side being connected to the first water inlet pipe and the first water return pipe, the heat exchange side being connected to the geothermal environment, so that geothermal water can exchange heat with the circulation side in the geothermal well; and a submersible pump, arranged below the heat exchanger, connected to and in communication with the heat exchange side, and configured to extract the geothermal water to the heat exchange side.

[0007] According to an embodiment of the present disclosure, the heat exchanger includes: an inner tube; a heat exchange tube group, which is arranged in the inner tube and has at least one heat exchange tube, the inner tube and the shell side outside the heat exchange tube group form the heat exchange side, and the tube side in the heat exchange tube forms the circulation side; a partition, which extends along the axial direction of the inner tube and has a water outlet formed at the upper part to separate the heat exchange side into a first part and a second part connected at the upper part; wherein the circulating water flowing through the circulation side and the geothermal water flowing through the heat exchange side are configured to flow in opposite directions to form countercurrent heat exchange.

[0008] According to an embodiment of the present disclosure, the heat exchanger further includes: a first connecting member, arranged at the upper portion of the inner tube, having a first water inlet connected to the first water inlet pipe, and a first water return port connected to the first water return pipe, the first water inlet and the first water return port being located on both sides of the partition to be isolated; and a second connecting member, arranged at the lower portion of the inner tube, having a second water inlet connected to the first portion and a second water return port connected to the second portion.

[0009] According to an embodiment of the present disclosure, the second water inlet is arranged in the middle part of the second connecting member, and in the projection along the axial direction of the inner tube, the projection of the center of the second water inlet coincides with the projection of the axis of the second connecting member; the second water return port is offset from the axis of the second connecting member.

[0010] According to an embodiment of the present disclosure, the heat exchange device further includes: a second water inlet pipe, the second water inlet pipe is connected to the second water inlet and is coaxially arranged with the second connecting member.

[0011] According to an embodiment of the present disclosure, the second water inlet pipe includes a first end located on the heat exchange side and a second end located outside the heat exchange side; wherein the first end is provided with a water retaining cover to connect the second water inlet pipe with the first part and isolate it from the second part.

[0012] According to an embodiment of the present disclosure, the single-well heat extraction system also includes: a temperature collection device configured to collect the inlet water temperature and / or return water temperature of the above-mentioned geothermal water; and a flow collection device configured to collect the inlet water flow and / or return water flow of the above-mentioned geothermal water.

[0013] According to an embodiment of the present disclosure, a first body of a temperature collection device suitable for collecting the inlet temperature of the above-mentioned geothermal water is arranged outside the above-mentioned second water inlet pipe, and a detection end of the above-mentioned first body is located in the above-mentioned second water inlet pipe; and / or, a second body of a flow collection device suitable for collecting the inlet flow of the above-mentioned geothermal water is arranged outside the above-mentioned second water inlet pipe, and a detection end of the above-mentioned first body is located in the above-mentioned second water inlet pipe.

[0014] According to an embodiment of the present disclosure, a first body of a temperature collection device suitable for collecting the return water temperature of the geothermal water is disposed on the second connecting member, and a detection end of the first body is located in the second portion.

[0015] According to an embodiment of the present disclosure, the temperature collection device and / or the flow collection device are communicatively connected to the submersible pump.

[0016] According to the technical solution provided by the exemplary embodiment of the present disclosure, the single-well heat extraction system sets the heat exchange device for exchanging heat between the geothermal water currently extracted from the geothermal well and the external water environment in the geothermal well. In other words, the geothermal water extracted from the geothermal well is no longer extracted outside the geothermal well and then exchanged with the heat exchanger, but the process of extracting geothermal water and exchanging heat between geothermal water and circulating water are both set in the geothermal well. For this reason, it can be regarded that the single-well heat extraction system meets the requirement of equal amount of recharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a single-well heat extraction system according to an embodiment of the present disclosure is schematically shown, in which the proportional relationship of each part along the vertical direction is modified;

[0018] Figure 2 yes Figure 1 a perspective view of an upper portion of a heat exchanger of the illustrated exemplary embodiment;

[0019] Figure 3 yes Figure 2 The heat exchanger of the exemplary embodiment shown is a perspective view with the outer tube omitted;

[0020] Figure 4 yes Figure 3 The heat exchanger of the exemplary embodiment shown is a perspective view with the first connecting member omitted;

[0021] Figure 5 yes Figure 4 A perspective view of the heat exchanger of the illustrated exemplary embodiment with the connector plate omitted; and

[0022] Figure 6 yes Figure 1 The illustrated exemplary embodiment is a perspective view of the lower portion of a heat exchanger with the inner tube omitted.

[0023] In the drawings, the meanings of the reference numerals are as follows:

[0024] 1. Well platform;

[0025] 2. Uphole equipment;

[0026] 21. First water inlet pipe;

[0027] 22. The first water return pipe;

[0028] 3. Heat exchange device;

[0029] 31. Heat exchanger;

[0030] 311, inner tube;

[0031] 312, first connecting member;

[0032] 313, connecting pipe;

[0033] 314. Heat exchange tube group;

[0034] 315, partition;

[0035] 3151, water outlet;

[0036] 316, connector plate;

[0037] 317, second connecting member;

[0038] 3171, second water inlet;

[0039] 3172, the second water return port;

[0040] 318, water shield;

[0041] 319, foreign control;

[0042] 32. Submersible pump;

[0043] 33. Insulation pipe;

[0044] 4. Temperature collection device;

[0045] 5. Flow collection device; and

[0046] 6. Second water inlet pipe. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0048] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0049] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0050] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0051] At present, the heat extraction system for geothermal wells generally extracts geothermal water from the geothermal well, then exchanges the extracted geothermal water with heat exchange equipment outside the well (such as a plate heat exchanger). After the heat exchange is completed, the low-temperature geothermal water is re-injected through the geothermal well.

[0052] With the emphasis on geothermal energy recycling and the requirement for groundwater balance, some standards have put forward corresponding requirements for the recharge volume of geothermal wells. For example, it is required that the recharge volume of geothermal tail water in the same layer of geothermal wells must reach more than 95% (even requiring equal recharge, that is, under ideal conditions, the recharge volume of geothermal tail water should be equal to or slightly greater than the extraction volume).

[0053] Therefore, how to provide a single-well heat extraction system that can effectively increase the reinjection volume of geothermal water has become a technical problem that needs to be solved urgently.

[0054] Figure 1 A schematic diagram of a single-well heat extraction system according to an embodiment of the present disclosure is schematically shown, in which the proportional relationship of each part along the vertical direction is modified.

[0055] According to the single well heat extraction system provided by the present disclosure, Figure 1 As shown, it includes a well platform 1, an above-the-hole device 2 and a heat exchange device 3. The well platform 1 is arranged at the wellhead of the geothermal well. The above-the-hole device 2 is arranged on the well platform 1, and has a first water inlet pipe 21 and a first water return pipe 22 connected to the external water environment. The heat exchange device 3 is arranged in the geothermal well, and the heat exchange device 3 includes a heat exchanger 31 and a submersible pump 32. The heat exchanger 31 has a circulation side (which can be regarded as the cold side of the heat exchanger) and a heat exchange side (which can be regarded as the hot side of the heat exchanger). The circulation side is connected to the first water inlet pipe 21 and the first water return pipe 22, and the heat exchange side is connected to the geothermal environment, so that the geothermal water exchanges heat with the circulation side in the geothermal well. The submersible pump 32 is arranged below the heat exchanger 31, connected to the heat exchange side, and the submersible pump 32 is also provided with an insulation pipe 33 outside, which is configured to extract the geothermal water to the heat exchange side.

[0056] In an illustrative embodiment, referring to Figure 1 As shown, the single-well heat extraction system includes but is not limited to being applied to any one of shallow geothermal wells (depth of about 200 meters to 500 meters), mid-level geothermal wells (depth of about 500 meters to 1500 meters) and deep geothermal wells (depth is usually about 1500 meters and above). In detail, a well platform is provided at the wellhead of the geothermal well, and the well platform includes but is not limited to a foundation provided at the wellhead, and a platform structure built on the foundation (such as a steel structure and / or a concrete structure). Furthermore, an above-the-hole device 2 is also provided on the well platform 1, which mainly includes a first water inlet pipe 21 and a first water return pipe 22, and the first water inlet pipe 21 and the first water return pipe 22 are configured to lead the circulating water of the external water use environment into the heat exchange device 3, so as to extract heat from the geothermal water as a cold source.

[0057] It should be noted that the first water inlet pipe 21 and the second water return pipe 22 are named with the heat exchanger 31 as the main body, that is, the first water inlet pipe 21 is suitable for supplying circulating water to the circulation side of the heat exchanger 31, and the first water return pipe 22 is suitable for guiding the circulating water to the outside of the heat exchanger 31. In other words, the first water inlet pipe 21 is equivalent to the return end of the external water environment, and the first water return pipe 22 is equivalent to the water inlet end of the external water environment. Taking this as an example, the second water inlet pipe 6, the second water return pipe, the first water inlet, the first water return, the second water inlet and the second water inlet described below are also named with the heat exchanger 31 as the main body, so they are not repeated here.

[0058] In such an implementation, the single-well heat extraction system sets the heat exchange device 3 for exchanging heat between the geothermal water currently extracted from the geothermal well and the external water environment in the geothermal well. In other words, the geothermal water extracted from the geothermal well is no longer extracted outside the geothermal well and then exchanged with the heat exchanger 31, but the process of extracting geothermal water and exchanging heat between geothermal water and circulating water are both set in the geothermal well. In this way, the single-well heat extraction system can achieve heat extraction only from geothermal water without extracting geothermal water outside the geothermal well. For this reason, the single-well heat extraction system can be regarded as meeting the requirement of equal amount of reinjection.

[0059] Figure 2 yes Figure 1 A perspective view of the upper portion of a heat exchanger of the exemplary embodiment shown. Figure 3 yes Figure 2 The heat exchanger of the exemplary embodiment shown is a perspective view in which the outer tube is omitted.

[0060] According to the embodiments of the present disclosure, Figures 2 to 4As shown, the heat exchanger 31 includes an inner tube 311, a heat exchange tube group 314 and a partition 315. The heat exchange tube group 314 is arranged in the inner tube 311 and has at least one heat exchange tube. The inner tube 311 and the shell side outside the heat exchange tube group 314 form a heat exchange side, and the tube side in the heat exchange tube forms a circulation side. The partition 315 extends along the axial direction of the inner tube 311 and has a water outlet 3151 formed on the upper part to separate the heat exchange side into a first part and a second part that are connected at the upper part.

[0061] In an illustrative embodiment, Figure 2 and Figure 3 As shown, the heat exchanger 31 further includes an outer tube 319 coaxially sleeved outside the inner tube 311 (ie, the axes of the inner tube 311 and the outer tube 319 coincide with each other). Figure 3 As shown, a plurality of ribs are provided on the outer wall of the inner tube 311, and a portion of the ribs are provided along the circumference of the inner tube 311 (such as Figure 3 The ribs are evenly spaced along the axial direction of the inner tube 311 (as shown in the clockwise or counterclockwise direction) and extend in the axial direction. The other part of the ribs are evenly spaced along the axial direction of the inner tube 311 (as shown in the clockwise or counterclockwise direction). Figure 3 The outer tube 319 is arranged in the vertical direction as shown in the figure, and extends in the circumferential direction to improve the structural strength of the heat exchanger 31. Furthermore, the outer tube 319 is arranged outside the rib plate and is spaced apart from the outer wall of the inner tube 311. The portion between the inner tube 311 and the outer tube 319 can be filled with insulation materials, such as insulation cotton, to isolate the heat transfer between the tube side of the heat exchanger and the external environment, thereby reducing the heat loss caused by the heat exchange between the geothermal water and the outside of the tube during the heat exchange process, so as to improve the heat exchange effect of the heat exchanger.

[0062] Figure 4 yes Figure 3 The heat exchanger of the exemplary embodiment shown is a perspective view in which the first connecting member is omitted. Figure 5 yes Figure 4 The heat exchanger of the exemplary embodiment shown is a perspective view omitting the connector plate. Figure 6 yes Figure 1 The illustrated exemplary embodiment is a perspective view of the lower portion of a heat exchanger with the inner tube omitted.

[0063] According to the embodiments of the present disclosure, Figures 4 to 6 As shown, the heat exchanger 31 also includes a first connecting member 312 and a second connecting member 317. The first connecting member 312 is arranged at the upper part of the inner tube 311, and has a first water inlet connected to the first water inlet pipe 21, and a first water return port connected to the first water return pipe 22. The first water inlet and the first water return port are located on both sides of the partition 315 to be isolated. The second connecting member 317 is arranged at the lower part of the inner tube 311, and has a second water inlet 3171 connected to the first part and a second water return port 3172 connected to the second part. Further, a connecting pipe 313 is also arranged on the first connecting member 312, and one end of the connecting pipe 313 (such as Figure 3 and Figure 4 The upper end (not shown) of the connecting pipe 313 passes through the first connecting piece 312, and the other end (the lower end, not shown) of the connecting pipe 313 passes through the first part or the second part to discharge the air in the heat exchange side to prevent the formation of an air layer in the heat exchange side.

[0064] According to the embodiments of the present disclosure, Figures 4 to 6 As shown, the circulating water flowing through the circulation side and the geothermal water flowing through the heat exchange side are configured to flow in opposite directions to form countercurrent heat exchange.

[0065] In an exemplary implementation, Figure 4 and Figure 5 As shown, a substantially cylindrical cavity is formed in the inner tube 311, and a partition 315 is arranged in the middle of the cavity. Figure 4 The cylindrical cavity is divided into two approximately semi-cylindrical sub-cavities, one of which (such as the one located at Figure 4 The upper sub-cavity shown in FIG. 1 is used as the first part, and the other sub-cavity (such as the one located at Figure 4 The lower sub-chamber shown in the figure is used as the second part. Further, a water outlet 3151 is provided at the upper end of the partition 315, and the length of the water outlet is configured to be substantially the same as the inner diameter of the inner tube 311, or slightly smaller than the inner diameter of the inner tube 311, and specifically should be suitable to meet the flow requirement of geothermal water.

[0066] In an exemplary implementation, as shown in 4 and Figure 6 As shown, the heat exchange tube group 314 includes a plurality of heat exchange tubes. In detail, the plurality of heat exchange tubes include but are not limited to being configured as a substantially U-shaped tube, and the U-shaped tube includes but is not limited to being made of a material with good thermal conductivity (such as copper). Further, one end of the plurality of heat exchange tubes is located in the first part, and the other end is located in the second part, and both ends of each heat exchange tube are arranged upward and connected to the porous joint plate 316.

[0067] In an exemplary implementation, Figure 4 and Figure 5 As shown, a plurality of heat exchange tubes are arranged in an array on the joint plate 316, and can be arranged in a row array and / or a column array. Among them, the position of the joint plate 316 close to the partition 315 has the largest number of heat exchange tubes because the width of this position is closest to the diameter of the inner tube; while the number of heat exchange tubes arranged at the edge position close to the joint plate 316 away from the partition 315 is relatively small. Furthermore, the axial length of the heat exchange tube close to the partition 315 is relatively short, while the axial length of the heat exchange tube away from the partition 315 is relatively long. In this way, through the above-mentioned arrangement, more heat exchange tubes can be arranged in the inner tube 311 to enhance the heat exchange effect between the heat exchange tube and the geothermal water.

[0068] In an illustrative embodiment, Figure 4 and Figure 6 As shown, the water inlet and water return ends of the circulation side (i.e., the heat exchange tube group 314) of the heat exchanger 31 are both arranged on the upper joint plate 316, while the water inlet and water return ends (i.e., the second water inlet 3171 and the second water return 3172) of the heat exchange side of the inner tube 311 are arranged on the second connector 317. Through the above design, the geothermal water flows upward in the heat exchange side first, and then flows downward after passing through the water outlet; while the circulation water flows downward in the circulation side first, and then flows upward after passing through the elbow part.

[0069] In such an embodiment, by configuring the relative positions of the first water inlet pipe 21 and the first water return pipe 22 and the first part and the second part, the flow direction of the circulating water when passing through the first part and the second part is always opposite to the flow direction of the geothermal water. In this way, the partition 315 not only extends the heat exchange length of the heat exchange pipe and the geothermal water, but also realizes the countercurrent heat exchange between the circulating water and the geothermal water, which can greatly improve the heat exchange effect of the heat exchanger 31.

[0070] According to the embodiments of the present disclosure, Figure 6 As shown, the second water inlet 3171 is disposed in the middle of the second connecting member 317, and in the projection along the axis direction of the inner tube 311, the projection of the center of the second water inlet 3171 coincides with the projection of the axis of the second connecting member 317. The second water return port 3172 is offset from the axis of the second connecting member 317.

[0071] According to the embodiments of the present disclosure, Figure 6 As shown, the heat exchange device 3 further includes a second water inlet pipe 6. The second water inlet pipe 6 is connected to the second water inlet 3171 and is coaxially arranged with the second connecting member 317.

[0072] According to the embodiments of the present disclosure, Figure 6 As shown, the second water inlet pipe 6 includes a first end located at the heat exchange side and a second end located outside the heat exchange side. The first end is provided with a water shield 318 to connect the second water inlet pipe 6 with the first part and isolate it from the second part.

[0073] In an illustrative embodiment, Figure 6 As shown, a roughly circular second water inlet 317 is concentrically arranged in the middle of the second connecting member 317. Further, the first end of the second water inlet pipe 6 is located in the second water inlet 317 and extends to the bottom of the heat exchange tube group 314. Furthermore, the first end is provided with a water shield 318, wherein the water shield 318 includes but is not limited to being configured as a roughly circular plate structure, and the water shield 318 is arranged in the axial direction of the inner tube (such as Figure 6 The second water inlet 3171 is spaced apart from each other in the up and down direction shown in FIG. Figure 6The right end shown in FIG. 10 ) forms a reversing flow channel with the second water inlet 3171 (even if the geothermal water is heated by Figure 6 As shown, the water flows upward to the right to allow the first water portion (such as Figure 6 The geothermal water in the right half shown in FIG. 31 is blocked and diffuses radially along the inner tube 311; the other end of the circular water shield 318 (as shown in FIG. Figure 6 The left end shown in FIG. 1 is connected to the partition plate 315 to form a sealing structure so that the second part (such as Figure 6 The geothermal water (left half as shown) is blocked from flowing back downward and slowly disperses through a plurality of second water return ports 3172 to reduce the flow rate of the geothermal water on the heat exchange side, thereby achieving more sufficient heat exchange with the heat exchange tube group 314.

[0074] In an illustrative embodiment, the sum of the areas of the plurality of second water return ports 3172 includes, but is not limited to, being configured to be substantially the same as the area of ​​the second water inlet 3171. In detail, the sum of the areas of the plurality of second water return ports 3172 can be configured to be 90% to 100% of the area of ​​the second water inlet 3171, so that the flow rate of the water inlet end (i.e., the second water inlet 3171) of the heat exchange side is greater than or equal to the flow rate of the water outlet end (i.e., the second water return port 3172). In this way, it is beneficial to make the heat exchange between the geothermal water and the circulating water in the heat exchange tube group 314 more sufficient.

[0075] According to the embodiments of the present disclosure, Figure 6 As shown, the single well heat extraction system further includes a temperature collection device 4 and a flow collection device 5. The temperature collection device 4 is configured to collect the inlet water temperature and / or the return water temperature of the geothermal water. The flow collection device 5 is configured to collect the inlet water flow and / or the return water flow of the geothermal water.

[0076] According to the embodiments of the present disclosure, Figure 6 As shown, the first body of the temperature collection device 4 for collecting the inlet temperature of geothermal water is arranged outside the second water inlet pipe 6, and the detection end of the first body is located inside the second water inlet pipe 6. And / or, the second body of the flow collection device 5 for collecting the inlet flow of geothermal water is arranged outside the second water inlet pipe 6, and the detection end of the first body is located inside the second water inlet pipe 6.

[0077] According to the embodiments of the present disclosure, Figure 6 As shown, the first body of the temperature collection device 4 suitable for collecting the return water temperature of geothermal water is arranged on the second connecting member 317, and the detection end of the first body is located in the second part.

[0078] In an exemplary embodiment, the temperature acquisition device 4 includes but is not limited to using two temperature transmitters (i.e., the first body). Specifically, a detection end of a temperature transmitter penetrates into the second part (e.g., the first body) through a hole (which may be the second water return port 3172 or other through hole similar to the second water return port 3172) provided by the second connecting member 317. Figure 6 The left half as shown in the figure is in the left half) to detect the return water temperature of the geothermal water after heat exchange, and the detection end of another temperature transmitter is set upstream of the second water inlet 3172 through the side wall of the second water inlet pipe 6 to detect the inlet water temperature of the geothermal water before heat exchange.

[0079] In an exemplary implementation, the flow collection device 5 includes but is not limited to using two flow transmitters (i.e., the second body). In detail, the detection ends of the two flow transmitters are arranged upstream of the second water inlet 3172 through the side wall of the second water inlet pipe 6 to detect the water inlet flow of the geothermal water before heat exchange. Further, the detection ends of the two flow transmitters are arranged at different positions upstream of the second water inlet 3172 to respectively detect the flow rate of the geothermal water at at least two positions entering the second water inlet 3172.

[0080] In such an embodiment, the reason why only the main bodies (i.e., the first body and the second body) of the collection devices (i.e., the temperature collection device 4 and the flow collection device 5) suitable for detecting the geothermal water parameters (such as the above-mentioned temperature and flow) located upstream of the second water inlet 3172 are arranged outside the second water inlet pipe 6, and only the detection end is arranged inside the second water inlet pipe 6 is to prevent the flow rate of the geothermal water entering the heat exchange side from being reduced due to the obstruction of the collection device (thus causing heat loss), so that the geothermal water can enter the heat exchange side at a higher temperature.

[0081] According to an embodiment of the present disclosure, the temperature collection device 4 and / or the flow collection device 5 are communicatively connected to the submersible pump 32 .

[0082] In an illustrative embodiment, the signal output ends of the temperature acquisition device 4 and the flow acquisition device 5 include but are not limited to communication connection with an external control device (such as an acquisition card, a single-chip microcomputer, a PLC, a computer, and other devices with signal acquisition functions, etc.) to collect the temperature difference of the geothermal water after heat exchange and the water inflow of the geothermal water. Further, the control device is also configured to be connected to the control end of the submersible pump 32, so as to adjust the operating power of the submersible pump 32.

[0083] In such an embodiment, the temperature acquisition device 4 and the flow acquisition device 5 are used to respectively acquire the temperature difference after the heat exchange of the geothermal water and the water inflow of the geothermal water, so as to calculate the heat exchange amount of the geothermal water flowing through the heat exchange side. On this basis, the submersible pump 32 is adjusted according to the heat exchange amount by adjusting the operating parameters (such as adjusting the operating power), and the water inflow of the geothermal water can be further adjusted, so that the circulating water after the heat exchange with the geothermal water can be maintained at (or adjusted to) a suitable temperature, so as to meet the heat collection requirements of the external water use environment.

[0084] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only for reference to the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0085] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A single well heat extraction system, characterized in that: include: A well platform (1), arranged at the wellhead of a geothermal well; An above-the-well device (2) is arranged on the well platform (1) and has a first water inlet pipe (21) and a first water return pipe (22) which are in communication with an external water environment; The heat exchange device (3) is arranged in the geothermal well and comprises: a heat exchanger (31) having a circulation side and a heat exchange side, the circulation side being connected to the first water inlet pipe (21) and the first water return pipe (22), and the heat exchange side being connected to a geothermal environment so that geothermal water in the geothermal well can exchange heat with the circulation side; and A submersible pump (32) is disposed below the heat exchanger (31), is connected to the heat exchange side, and is configured to extract the geothermal water to the heat exchange side.

2. The heat extraction system according to claim 1, characterized in that: The heat exchanger (31) comprises: Inner tube (311); A heat exchange tube group (314) is arranged in the inner tube (311) and comprises at least one heat exchange tube; the inner tube (311) and the shell side outside the heat exchange tube group (314) form the heat exchange side, and the tube side inside the heat exchange tube forms the circulation side; A partition plate (315) extending along the axial direction of the inner tube (311) and having a water outlet (3151) formed at an upper portion thereof, so as to separate the heat exchange side into a first portion and a second portion which are connected at the upper portion; The circulating water flowing through the circulation side and the geothermal water flowing through the heat exchange side are configured to flow in opposite directions to form countercurrent heat exchange.

3. The heat extraction system according to claim 2, characterized in that: The heat exchanger (31) further comprises: a first connecting member (312) disposed on the upper portion of the inner tube (311), having a first water inlet connected to the first water inlet pipe (21), and a first water return port connected to the first water return pipe (22), the first water inlet and the first water return port being located on both sides of the partition (315) to be isolated; and The second connecting member (317) is arranged at the lower part of the inner tube (311), and has a second water inlet (3171) connected to the first part and a second water return port (3172) connected to the second part.

4. The heat extraction system according to claim 3, characterized in that: The second water inlet (3171) is arranged in the middle of the second connecting member (317), and in the projection along the axial direction of the inner tube (311), the projection of the center of the second water inlet (3171) coincides with the projection of the axial line of the second connecting member (317); The second water return port (3172) is arranged offset from the axis of the second connecting member (317).

5. The heat extraction system according to claim 3 or 4, characterized in that: The heat exchange device (3) further comprises: A second water inlet pipe (6), the second water inlet pipe (6) is connected to the second water inlet (3171) and is coaxially arranged with the second connecting member (317).

6. The heat extraction system according to claim 5, characterized in that: The second water inlet pipe (6) comprises a first end located on the heat exchange side and a second end located outside the heat exchange side; The first end is provided with a water shield (318) to connect the second water inlet pipe (6) with the first part and isolate it from the second part.

7. The heat extraction system according to claim 6, characterized in that: Also includes: A temperature collection device (4) configured to collect the inlet water temperature and / or return water temperature of the geothermal water; as well as The flow collection device (5) is configured to collect the inflow flow and / or return flow of the geothermal water.

8. The heat extraction system according to claim 7, characterized in that: A first body of a temperature collection device (4) suitable for collecting the inlet temperature of the geothermal water is arranged outside the second inlet pipe (6), and a detection end of the first body is located inside the second inlet pipe (6); And / or, the second body of the flow rate collection device (5) suitable for collecting the water inlet flow rate of the geothermal water is arranged outside the second water inlet pipe (6), and the detection end of the first body is located inside the second water inlet pipe (6).

9. The heat extraction system according to claim 7, characterized in that: A first body of a temperature collection device (4) suitable for collecting the return water temperature of the geothermal water is arranged on the second connecting piece (317), and a detection end of the first body is located in the second part.

10. The heat extraction system according to any one of claims 7 to 9, characterized in that: The temperature collection device (4) and / or the flow collection device (5) are communicatively connected to the submersible pump (32).

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