Coaxial sleeve heat removal and supply system for medium-deep geothermal well

Abstract

The utility model provides a medium-deep layer geothermal well coaxial sleeve heat taking and heating system which comprises a heat supply circulation pipeline, a plate heat exchanger, a heat pump unit, a geothermal well heat exchange device, a geothermal circulation pipeline and a control unit. In the initial operation stage of the system and when the outlet water temperature of geothermal water is high, the plate heat exchanger is started preferentially for heat exchange, the high-temperature geothermal water is used for heating after heat exchange, and when the outlet water temperature of the geothermal water is reduced to the openable temperature of the heat pump unit, the plate heat exchanger is closed, the heat pump unit is started, and the heat pump unit is adopted for heating. Through arrangement of the plate heat exchanger and pipeline switching of the electric valve, rapid, stable, reliable and stable operation of the system can be ensured. The problem that the heat pump unit cannot be started due to the initial heating stage or the high geothermal water temperature is solved; meanwhile, through application of various automatic control instruments and automatic control systems, stable, safe, efficient and automatic operation of the system is achieved.

Description

Technical Field

[0001] This utility model relates to the field of geothermal heating systems, and more specifically, to a coaxial casing heat extraction and heating system for medium-deep geothermal wells. Background Technology

[0002] Existing medium-deep coaxial casing heating systems extract heat from geothermal wells and use heat pumps to enhance the heat quality for heating. However, because the inlet water temperature of the heat pump evaporator should not be too high, the heat pump may fail to start during the initial operation of the system and when the geothermal water outlet temperature is high, thus affecting the normal operation of the heating system. Utility Model Content

[0003] The main objective of this invention is to provide a coaxial casing heat extraction and heating system for medium-deep geothermal wells, so as to at least solve the problem that the heat pump cannot be turned on in the initial stage of operation and when the geothermal water outlet temperature is high in the existing medium-deep coaxial casing heating system, thereby affecting the normal operation of the heating system.

[0004] To achieve the above objectives, this utility model provides a coaxial casing heat extraction and heating system for medium-deep geothermal wells, comprising: a heating circulation pipeline connected to a heating user; a plate heat exchanger and a heat pump unit, the plate heat exchanger having a first heating end and a first heat absorption end, and the heat pump unit having a second heating end and a second heat absorption end, both the first heating end and the second heat absorption end being connected to the heating circulation pipeline to circulate heating water to the heating user through the heating circulation pipeline; a geothermal well heat exchange device installed inside the geothermal well to circulate heat exchange with the soil inside the geothermal well to form geothermal water at a preset temperature; and a geothermal circulation pipeline connected to the geothermal well heat exchange device. The heating device, the first heat-absorbing end, and the second heat-absorbing end are all connected. The geothermal circulation pipeline circulates and transports the geothermal water generated by the geothermal well heat exchange device to the first heat-absorbing end and the second heat-absorbing end to exchange heat with the heating water of the first heating end and the second heating end. The control unit is connected to the heating circulation pipeline, the plate heat exchanger, the heat pump unit, and the geothermal circulation pipeline. The control unit is used to automatically control and switch the plate heat exchanger or the heat pump unit to connect with the heating circulation pipeline and the geothermal circulation pipeline according to the outlet water temperature of the geothermal circulation pipeline so that the geothermal water in the geothermal circulation pipeline can exchange heat with the heating water in the heating circulation pipeline through one of the plate heat exchangers or the heat pump unit.

[0005] Furthermore, the heating circulation pipeline includes: a user-side circulation pipe connected to the heating user; a first electric valve installed at the return water port of the first heating end and connected to the return water pipe of the user-side circulation pipe; and a second electric valve installed at the return water port of the second heating end and connected to the return water pipe of the user-side circulation pipe. The control unit is connected to both the first and second electric valves to switch the operation of the plate heat exchanger or the heat pump unit.

[0006] Furthermore, the heating circulation pipeline also includes: a first control valve, installed on the return water pipe of the user-side circulation pipe, the first control valve being used to open or close the return water pipe of the user-side circulation pipe; a first temperature sensor, installed on the return water pipe of the user-side circulation pipe and adjacent to the first control valve, the first temperature sensor being used to monitor the temperature of the return water pipe of the user-side circulation pipe; a first pressure transmitter, installed on the return water pipe of the user-side circulation pipe and adjacent to the first temperature sensor, the first pressure transmitter being used to monitor the pressure of the return water pipe of the user-side circulation pipe; a first heat meter, installed on the return water pipe of the user-side circulation pipe and adjacent to the first pressure transmitter, the first heat meter being used to monitor the heat flowing through the return water pipe of the user-side circulation pipe; a first water replenishment and pressure stabilization device, connected to the user-side circulation pipe, for replenishing water to the user-side circulation pipe; and a heating circulation pump, installed on the return water pipe of the user-side circulation pipe, the heating circulation pump being used to drive the flow of heating water in the user-side circulation pipe.

[0007] Furthermore, the heating circulation pipeline also includes: a second control valve, installed on the inlet pipe of the user-side circulation pipe, the second control valve being used to open or close the inlet pipe of the user-side circulation pipe; a second temperature sensor, installed on the inlet pipe of the user-side circulation pipe and adjacent to the second control valve, the second temperature sensor being used to monitor the temperature of the inlet pipe of the user-side circulation pipe; and a second pressure transmitter, installed on the inlet pipe of the user-side circulation pipe and adjacent to the second temperature sensor, the second pressure transmitter being used to monitor the pressure of the inlet pipe of the user-side circulation pipe.

[0008] Furthermore, the geothermal circulation pipeline includes: a geothermal circulation pipe connected to the geothermal well heat exchange device; a third electric valve installed at the inlet of the first heat absorption end and connected to the inlet pipe of the geothermal circulation pipe; and a fourth electric valve installed at the inlet of the second heat absorption end and connected to the inlet pipe of the geothermal circulation pipe. The control unit is connected to both the third and fourth electric valves to switch the operation of the plate heat exchanger or the heat pump unit.

[0009] Furthermore, the geothermal circulation pipeline also includes: a third temperature sensor, installed on the inlet pipe of the geothermal circulation pipeline, which is used to monitor the temperature of the inlet pipe of the user-side circulation pipeline; and a third pressure transmitter, installed on the inlet pipe of the geothermal circulation pipeline and adjacent to the third temperature sensor, which is used to monitor the pressure of the inlet pipe of the geothermal circulation pipeline.

[0010] Furthermore, the geothermal circulation pipeline also includes: a second heat meter, installed on the return water pipe of the geothermal circulation pipe, used to monitor the heat flowing through the return water pipe of the geothermal circulation pipe; a second water replenishment and pressure stabilization device, connected to the geothermal circulation pipe, to replenish water to the geothermal circulation pipe; a geothermal circulation pump, installed on the return water pipe of the geothermal circulation pipe and adjacent to the second heat meter, used to drive the flow of geothermal water in the geothermal circulation pipe; a filter, installed on the return water pipe of the geothermal circulation pipe and adjacent to the geothermal circulation pump, used to filter impurities in the geothermal water in the geothermal circulation pipe; a fourth temperature sensor, installed on the return water pipe of the geothermal circulation pipe and adjacent to the filter, used to monitor the temperature of the return water pipe of the geothermal circulation pipe; and a fourth pressure transmitter, installed on the return water pipe of the geothermal circulation pipe and adjacent to the fourth temperature sensor, used to monitor the pressure of the return water pipe of the geothermal circulation pipe.

[0011] Furthermore, a regulating pipe is connected between the inlet and outlet pipes of the geothermal circulation pipe. The geothermal circulation pipeline also includes an electric regulating valve, which is installed on the regulating pipe. The electric regulating valve is used to regulate the flow rate through the regulating pipe to control the flow rate of geothermal water passing through the plate heat exchanger or heat pump unit.

[0012] This utility model discloses a coaxial casing heating system for medium-deep geothermal wells, comprising: a heating circulation pipeline connected to a user; a plate heat exchanger and a heat pump unit, the plate heat exchanger having a first heating end and a first heat absorption end, and the heat pump unit having a second heating end and a second heat absorption end, both the first and second heating ends being connected to the heating circulation pipeline to circulate heating water to the user; a geothermal well heat exchange device installed inside the geothermal well, circulating heat with the soil inside the well to form geothermal water at a preset temperature; and a geothermal circulation pipeline connected to the geothermal well heat exchange device. Both the first and second heat-absorbing ends are connected. The geothermal circulation pipeline circulates and transports the geothermal water generated by the geothermal well heat exchange device to the first and second heat-absorbing ends for heat exchange with the heating water of the first and second heating ends. The control unit is connected to the heating circulation pipeline, plate heat exchanger, heat pump unit, and geothermal circulation pipeline. The control unit is used to automatically control and switch the plate heat exchanger or heat pump unit to connect with the heating circulation pipeline and the geothermal circulation pipeline according to the outlet water temperature of the geothermal circulation pipeline, so that the geothermal water in the geothermal circulation pipeline can exchange heat with the heating water in the heating circulation pipeline through one of the plate heat exchanger or heat pump unit. This invention connects a plate heat exchanger in parallel with the heat pump unit in the system. During the initial operation of the system and when the geothermal water outlet temperature is high, the plate heat exchanger is activated first to exchange heat, using the high-temperature geothermal water for heating. Once the geothermal water outlet temperature drops to a temperature suitable for the heat pump unit to operate, the plate heat exchanger is shut off, and the heat pump unit is turned on for heating. Through the design of the plate heat exchanger and the switching of pipelines using electric valves, the system can be ensured to operate quickly, stably, and reliably. This avoids the problem of the heat pump unit failing to start due to the initial heating period or high geothermal water temperature. Furthermore, through the application of various automatic control instruments and systems, the system achieves stable, safe, efficient, and automated operation. Attached Figure Description

[0013] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0014] Figure 1 This is a schematic diagram of a coaxial casing heat extraction and heating system for a medium-deep geothermal well, which is an optional embodiment of this utility model.

[0015] The above figures include the following reference numerals:

[0016] 10. Heating circulation pipeline; 110. User-side circulation pipeline; 11. First electric valve; 12. Second electric valve; 13. First control valve; 14. First temperature sensor; 15. First pressure transmitter; 16. First heat meter; 17. First water supply and pressure stabilization device; 18. Heating circulation pump; 19. Second control valve; 111. Second temperature sensor; 112. Second pressure transmitter; 20. Plate heat exchanger; 21. First heating end; 22. First heat absorption end; 30. Heat pump unit; 31. Second heating end; 32. Hot end; 40. Second heat absorption end; 41. Geothermal well heat exchanger; 42. Outer protective pipe; 50. Central pipe; 51. Geothermal circulation pipeline; 52. Geothermal circulation pipe; 53. Third electric valve; 54. Fourth electric valve; 55. Third temperature sensor; 56. Third pressure transmitter; 57. Second heat meter; 58. Second water replenishment and pressure stabilization device; 59. Geothermal circulation pump; 510. Filter; 511. Fourth temperature sensor; 512. Fourth pressure transmitter; 60. Electric regulating valve; 513. Heating user. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] To achieve the above objectives, this utility model provides a coaxial casing heat extraction and heating system for medium-deep geothermal wells, comprising: a heating circulation pipeline 10, which is connected to a heating user 60; a plate heat exchanger 20 and a heat pump unit 30, wherein the plate heat exchanger 20 has a first heating end 21 and a first heat absorption end 22, and the heat pump unit 30 has a second heating end 31 and a second heat absorption end 32, both of which are connected to the heating circulation pipeline 10 to circulate heating water to the heating user 60; a geothermal well heat exchange device 40, installed inside the geothermal well, which circulates heat with the soil inside the geothermal well to form geothermal water at a preset temperature; and a geothermal circulation pipeline 50, which is connected to the geothermal well heat exchange device. The geothermal circulation pipeline 50 is connected to the first heat-absorbing end 22 and the second heat-absorbing end 32. The geothermal circulation pipeline 50 circulates and transports the geothermal water generated by the geothermal well heat exchange device 40 to the first heat-absorbing end 22 and the second heat-absorbing end 32 to exchange heat with the heating water of the first heating end 21 and the second heating end 31. The control unit is connected to the heating circulation pipeline 10, the plate heat exchanger 20, the heat pump unit 30 and the geothermal circulation pipeline 50. The control unit is used to automatically control and switch the plate heat exchanger 20 or the heat pump unit 30 to connect with the heating circulation pipeline 10 and the geothermal circulation pipeline 50 according to the outlet water temperature of the geothermal circulation pipeline 50 so that the geothermal water of the geothermal circulation pipeline 50 can exchange heat with the heating water of the heating circulation pipeline 10 through one of the plate heat exchanger 20 or the heat pump unit 30. This invention incorporates a plate heat exchanger 20 connected in parallel with the heat pump unit 30 within the system. During the initial operation of the system and when the geothermal water outlet temperature is high, the plate heat exchanger 20 is activated first to exchange heat, using the high-temperature geothermal water for heating. Once the geothermal water outlet temperature drops to a temperature suitable for the heat pump unit 30 to operate, the plate heat exchanger 20 is shut off, and the heat pump unit 30 is activated for heating. Through the design of the plate heat exchanger 20 and the switching of the electric valve pipeline, the system can be ensured to operate quickly, stably, and reliably. This avoids the problem of the heat pump unit 30 failing to start due to the initial heating period or high geothermal water temperature. Furthermore, the application of various automatic control instruments and systems achieves stable, safe, efficient, and automated operation of the system.

[0019] In specific implementation, the heating circulation pipeline 10 includes a user-side circulation pipe 110, a first electric valve 11, and a second electric valve 12. The user-side circulation pipe 110 is connected to the heating user 60. The first electric valve 11 is installed at the return water port of the first heating end 21 of the plate heat exchanger 20 and connected to the return water pipe of the user-side circulation pipe 110. The second electric valve 12 is installed at the return water port of the second heating end 31 of the heat pump unit 30 and connected to the return water pipe of the user-side circulation pipe 110. The control unit is connected to both the first electric valve 11 and the second electric valve 12 to control the opening of either the first electric valve 11 or the second electric valve 12, thereby switching the operation of the plate heat exchanger 20 or the heat pump unit 30. The return water of the plate heat exchanger 20 or the heat pump unit 30 can be flexibly closed through the first electric valve 11 and the second electric valve 12, thus achieving flexible switching between the plate heat exchanger 20 and the heat pump unit 30.

[0020] Furthermore, the heating circulation pipeline 10 also includes a first control valve 13, a first temperature sensor 14, a first pressure transmitter 15, a first heat meter 16, a first water replenishment and pressure stabilization device 17, and a heating circulation pump 18. The first control valve 13 is installed on the return water pipe of the user-side circulation pipe 110. The first control valve 13 is used to manually open or close the return water pipe of the user-side circulation pipe 110, thereby achieving connection and isolation between the return water pipe of the user-side circulation pipe 110 and the heating user 60. The first temperature sensor 14 is installed on the return water pipe of the user-side circulation pipe 110 and adjacent to the first control valve 13. The first temperature sensor 14 is used to monitor the temperature of the return water pipe of the user-side circulation pipe 110, thereby knowing the return water temperature of the heating user 60 in real time. The first pressure transmitter 15 is installed on the return water pipe of the user-side circulation pipe 110 and adjacent to the first temperature sensor 16. Adjacent to sensor 14, the first pressure transmitter 15 is used to monitor the pressure of the return water pipe of the user-side circulation pipe 110, thereby understanding the return water pressure of the heating user 60 in real time; the first heat meter 16 is installed on the return water pipe of the user-side circulation pipe 110 and adjacent to the first pressure transmitter 15. The first heat meter 16 is used to monitor the heat flowing through the return water pipe of the user-side circulation pipe 110, thereby understanding the heat loss after the heating water flows through the heating user 60 in real time; the first water replenishment and pressure stabilization device 17 is connected to the user-side circulation pipe 110 to replenish water to the user-side circulation pipe 110, thereby ensuring the internal pressure of the user-side circulation pipe 110 is stable; the heating circulation pump 18 is installed on the return water pipe of the user-side circulation pipe 110. The heating circulation pump 18 is used to drive the flow of heating water in the user-side circulation pipe 110, thereby providing water flow power for the entire user-side circulation pipe 110.

[0021] Furthermore, the heating circulation pipeline 10 also includes a second control valve 19, a second temperature sensor 111, and a second pressure transmitter 112. The second control valve 19 is installed on the inlet pipe of the user-side circulation pipeline 110. The second control valve 19 is used to open or close the inlet pipe of the user-side circulation pipeline 110. The second control valve 19 is opened or closed manually to realize the connection and isolation between the inlet pipe of the user-side circulation pipeline 110 and the heating user 60; the second temperature sensor 111... A first control valve 11 is installed on the inlet pipe of the user-side circulation pipe 110 and adjacent to the second control valve 19. The second temperature sensor 111 is used to monitor the temperature of the inlet pipe of the user-side circulation pipe 110, thereby knowing the inlet water temperature of the heating user 60 in real time. A second pressure transmitter 112 is installed on the inlet pipe of the user-side circulation pipe 110 and adjacent to the second temperature sensor 111. The second pressure transmitter 112 is used to monitor the pressure of the inlet pipe of the user-side circulation pipe 110, thereby knowing the inlet water pressure of the heating user 60 in real time. Through the application of automatic control instruments and automatic control systems such as the first control valve 13, the first temperature sensor 14, the first pressure transmitter 15, the first heat meter 16, the first water replenishment and pressure stabilization device 17, the heating circulation pump 18, the second control valve 19, the second temperature sensor 111, and the second pressure transmitter 112, the stable, safe, efficient, and automated operation of the system's heating circulation pipeline 10 is realized.

[0022] Furthermore, the geothermal circulation pipeline 50 includes a geothermal circulation pipe 51, a third electric valve 52, and a fourth electric valve 53. The geothermal circulation pipe 51 is connected to the geothermal well heat exchange device 40. The third electric valve 52 is located at the inlet of the first heat absorption end 22 and connected to the inlet pipe of the geothermal circulation pipe 51. The fourth electric valve 53 is located at the inlet of the second heat absorption end 32 and connected to the inlet pipe of the geothermal circulation pipe 51. The control unit is connected to both the third electric valve 52 and the fourth electric valve 53 to control one of them to open, thereby switching the operation of the plate heat exchanger 20 or the heat pump unit 30. The inlet water of the plate heat exchanger 20 or the heat pump unit 30 can be flexibly closed through the third electric valve 52 and the fourth electric valve 53, thereby realizing the flexible switching between the plate heat exchanger 20 and the heat pump unit 30.

[0023] Furthermore, the geothermal circulation pipeline 50 also includes a third temperature sensor 54 and a third pressure transmitter 55. The third temperature sensor 54 is installed on the inlet pipe of the geothermal circulation pipeline 51 and is used to monitor the temperature of the inlet pipe of the user-side circulation pipeline 110, thereby knowing the outlet water temperature of the geothermal well heat exchange device 40 in real time. The third pressure transmitter 55 is installed on the inlet pipe of the geothermal circulation pipeline 51 and is adjacent to the third temperature sensor 54. The third pressure transmitter 55 is used to monitor the pressure of the inlet pipe of the geothermal circulation pipeline 51, thereby knowing the outlet water pressure of the geothermal well heat exchange device 40 in real time.

[0024] Furthermore, the geothermal circulation pipeline 50 also includes a second heat meter 56, a second water replenishment and pressure stabilization device 57, a geothermal circulation pump 58, a filter 59, a fourth temperature sensor 510, and a fourth pressure transmitter 511. The second heat meter 56 is installed on the return water pipe of the geothermal circulation pipe 51 and is used to monitor the heat flowing through the return water pipe of the geothermal circulation pipe 51, thereby understanding in real time the heat loss of geothermal water after heat exchange through the plate heat exchanger 20 or the heat pump unit 30. The second water replenishment and pressure stabilization device 57 is connected to the geothermal circulation pipe 51 to replenish water to the geothermal circulation pipe 51, thereby ensuring the internal pressure of the geothermal circulation pipe 51 is stable. The geothermal circulation pump 58 is installed on the return water pipe of the geothermal circulation pipe 51 and is adjacent to the second heat meter 56. The geothermal circulation pump 58 is used to drive the geothermal circulation pipe. The geothermal water flows within the geothermal circulation pipe 51, providing water flow power for the entire geothermal circulation pipe 51. A filter 59 is installed on the return water pipe of the geothermal circulation pipe 51 and adjacent to the geothermal circulation pump 58. The filter 59 is used to filter impurities in the geothermal water within the geothermal circulation pipe 51. A fourth temperature sensor 510 is installed on the return water pipe of the geothermal circulation pipe 51 and adjacent to the filter 59. The fourth temperature sensor 510 is used to monitor the temperature of the return water pipe of the geothermal circulation pipe 51, thereby obtaining real-time information on the return water temperature of the geothermal well heat exchange device 40. A fourth pressure transmitter 511 is installed on the return water pipe of the geothermal circulation pipe 51 and adjacent to the fourth temperature sensor 510. The fourth pressure transmitter 511 is used to monitor the pressure of the return water pipe of the geothermal circulation pipe 51, thereby obtaining real-time information on the return water pressure of the geothermal well heat exchange device 40. Through the application of automatic control instruments and systems such as the second heat meter 56, the second water replenishment and pressure stabilization device 57, the geothermal circulation pump 58, the filter 59, the fourth temperature sensor 510 and the fourth pressure transmitter 511, the stable, safe and efficient automated operation of the geothermal circulation pipeline 50 of the system is realized.

[0025] Furthermore, a regulating pipe is connected between the inlet pipe and the return pipe of the geothermal circulation pipe 51. The geothermal circulation pipe 50 also includes an electric regulating valve 512, which is installed in the regulating pipe. The electric regulating valve 512 is used to regulate the flow rate through the regulating pipe to control the flow rate of geothermal water passing through the plate heat exchanger 20 or the heat pump unit 30.

[0026] In the specific installation and application of this utility model's medium-deep geothermal well coaxial casing heat extraction and heating system, the geothermal well is first drilled to a depth of 200-3000 meters (the specific depth depends on actual needs; 2500 meters is used as an example here). The geothermal well heat exchange device 40 includes an outer protective pipe 41 and a central pipe 42. The outer protective pipe 41 is made of J55 oil steel pipe with a diameter of Ф177.8×9.19, and the central pipe 42 is made of PE-RT-II type high-density polyethylene pipe with a diameter of Ф110×10. After well completion, they are connected by pipelines. The upper end of the cavity between the outer protective pipe 41 and the central pipe 42 is provided with a geothermal hot water return inlet, and the upper end of the central pipe 42 is provided with a heated geothermal hot water outlet. The above-ground machine room is equipped with a plate heat exchanger 20, a heat pump unit 30, a heating circulation pump 18, a geothermal circulation pump 58, a first water replenishment and pressure stabilization device 17, and a second water replenishment and pressure stabilization device 57. The heat pump unit 30 is a screw-type heat pump unit. According to the process schematic, the system is connected via pipelines. The analog signals, digital signals, and communication signals of the following components are connected to the control unit via low-voltage wiring: the first electric valve 11, the second electric valve 12, the third electric valve 52, the fourth electric valve 53, the first temperature sensor 14, the first pressure transmitter 15, the first heat meter 16, the first water supply and pressure stabilization device 17, the heating circulation pump 18, the second temperature sensor 111, the second pressure transmitter 112, the third temperature sensor 54, the third pressure transmitter 55, the second heat meter 56, the second water supply and pressure stabilization device 57, the geothermal circulation pump 58, the filter 59, the fourth temperature sensor 510, and the fourth pressure transmitter 511. The control unit uses a PLC control cabinet. The heat pump unit 30, the geothermal circulation pump 58, the heating circulation pump 18, the first electric valve 11, the second electric valve 12, the third electric valve 52, and the fourth electric valve 53 are connected to the equipment from the distribution box to complete the power supply for the electrical equipment. After the process piping and equipment system, low-voltage system, and high-voltage system are connected, the system is built. After the control logic and automatic control algorithm are written into the PLC controller, the system can run automatically after the equipment is powered on.

[0027] System Operation: When the system starts running, the first electric valve 11 and the third electric valve 52 are opened, and the second electric valve 12 and the fourth electric valve 53 are closed. The heating circulation pump 18 and the geothermal circulation pump 58 are started. At this time, the geothermal water outlet temperature at the third temperature sensor 54 is 58℃. After passing through the plate heat exchanger 20, the geothermal water temperature drops to 48℃. After passing through the second heat meter 56, the geothermal water enters the geothermal circulation pump 58 for pressurization, enters the geothermal well heat exchange device 40 through the pipeline for heating, and after passing through the outer protective pipe 41 for heat exchange, it flows out through the central pipe 42, and then enters the plate heat exchanger 20 through the pipeline for heat exchange. After cooling down, it flows out of the plate heat exchanger 20. The geothermal water circulates multiple times in the pipeline. As the heat is continuously absorbed by the heating users, the geothermal water outlet temperature gradually decreases from 58℃. At this time, the low-temperature water from heating user 60 is pressurized by heating circulation pump 18 and enters plate heat exchanger 20 to absorb heat from geothermal water and be heated. As the system circulates multiple times, the heating water temperature continuously increases. The control unit monitors the supply and return water temperatures of geothermal well heat exchange device 40 in real time through third temperature sensor 54 and fourth temperature sensor 510, monitors the supply and return water temperatures of heating in real time through second temperature sensor 111 and first temperature sensor 14, monitors the supply and return water pressure of geothermal well heat exchange device 40 in real time through third pressure transmitter 55 and fourth pressure transmitter 511, and monitors the supply and return water pressure of heating user 60 in real time through first pressure transmitter 15 and second pressure transmitter 112. As the system operates, the outlet water temperature of the geothermal well heat exchanger 40 gradually decreases. When the geothermal supply water temperature monitored by the third temperature sensor 54 drops to 25℃ (or the highest inlet water temperature of the heat pump unit evaporator), the control unit automatically closes the first electric valve 11 and the third electric valve 52, opens the second electric valve 12 and the fourth electric valve 53, and starts the heat pump unit 30. The heat provided by the water supplied by the geothermal well heat exchanger 40 passes through the evaporator of the heat pump unit 30, and the water temperature drops to 10℃. After being pressurized by the geothermal circulation pump 58 through the pipeline, it enters the... Inside the outer protective pipe 41 of the geothermal well heat exchange device 40, heat is exchanged with the medium-deep underground soil outside the outer protective pipe 41. After being fully heated at the deepest point, the water enters the central pipe 42 and flows out through the pipeline to continue circulating and supplying heat. The heating circulating water entering the heat pump unit 30 is heated to 45°C by the condenser of the heat pump unit 30 and then flows out to the heating user 60. After heating the room, the temperature drops to 35°C and then flows out. After being pressurized by the heating circulation pump 18, it flows through the pipeline to the condenser of the heat pump unit 30. This cycle continues, achieving continuous heating for the heating user 60. The above system utilizes the coaxial sleeve composed of the outer protective pipe 41 and the central pipe 42 to extract heat from the medium-deep geothermal well. Through the alternating switching of the plate heat exchanger 20 and the heat pump unit 30, a stable heating supply to the heating user 60 is achieved.

[0028] This invention combines a medium-deep geothermal heat extraction system with a heating system to construct a complete and feasible medium-deep geothermal well coaxial casing heat extraction and heating utilization system. The low-grade heat extracted from the geothermal well is upgraded by a heat pump unit 30 before being used for building heating. This invention incorporates a plate heat exchanger 20 in the system. During the initial operation of the system, or when the geothermal water temperature is high and exceeds the start-up temperature of the heat pump unit 30, the plate heat exchanger 20 can be used for heat exchange and heating. Temperature and pressure sensors are installed on the geothermal well supply and return water pipes to monitor the grade and operating status of the geothermal well heat extraction in real time. Once the system is stable, it can switch to the heat pump unit 30 for heating, solving the problem of the heat pump unit 30 failing to start due to the high geothermal water temperature in traditional systems. Furthermore, an electric valve is installed in the system, which opens and closes based on the real-time water temperature measured by the temperature sensor, thereby achieving automatic switching between the plate heat exchanger 20 and the heat pump unit 30, resulting in a high degree of automation in system operation. The system of this utility model has a simple process flow, is easy to implement, and is highly practical, with significant technological advancements and practical value.

[0029] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A coaxial casing heat extraction heating system for a medium-deep geothermal well, characterized in that, The application relates to a heat supply system, which comprises: a heat supply circulating pipeline (10) in communication with a heat supply user (60); a plate heat exchanger (20) having a first heat supply end (21) and a first heat absorption end (22), and a heat pump unit (30) having a second heat supply end (31) and a second heat absorption end (32), wherein the first heat supply end (21) and the second heat supply end (31) are both in communication with the heat supply circulating pipeline (10) to circulate heating water to the heat supply user (60) through the heat supply circulating pipeline (10); a geothermal well heat exchange device (40) installed in a geothermal well to exchange heat with soil in the geothermal well to form geothermal water with a preset temperature; a geothermal circulating pipeline (50) in communication with the geothermal well heat exchange device (40) and the first heat absorption end (22) and the second heat absorption end (32), wherein the geothermal circulating pipeline (50) circulates geothermal water formed by the geothermal well heat exchange device (40) to the first heat absorption end (22) and the second heat absorption end (32) to exchange heat with heating water of the first heat supply end (21) and the second heat supply end (31); a control unit connected with the heat supply circulating pipeline (10), the plate heat exchanger (20), the heat pump unit (30) and the geothermal circulating pipeline (50), and used for automatically controlling and switching the plate heat exchanger (20) or the heat pump unit (30) to be in communication with the heat supply circulating pipeline (10) and the geothermal circulating pipeline (50) according to the outlet water temperature of the geothermal circulating pipeline (50) so that the geothermal water of the geothermal circulating pipeline (50) exchanges heat with the heating water of the heat supply circulating pipeline (10) through one of the plate heat exchanger (20) or the heat pump unit (30).

2. The coaxial casing heat extraction system for heating according to claim 1, characterized in that, The heat supply circulating pipeline (10) comprises: a user side circulating pipeline (110) in communication with the heat supply user (60); a first electric valve (11) arranged at a water return port of the first heat supply end (21) and connected with a water return pipeline of the user side circulating pipeline (110); a second electric valve (12) arranged at a water return port of the second heat supply end (31) and connected with the water return pipeline of the user side circulating pipeline (110); wherein the control unit is connected with the first electric valve (11) and the second electric valve (12) to switch the plate heat exchanger (20) or the heat pump unit (30) to run.

3. The coaxial casing heat extraction system for heating according to claim 2, characterized in that, The heat supply circulating pipeline (10) further comprises: a first control valve (13) arranged at the water return pipeline of the user side circulating pipeline (110) and used for opening or closing the water return pipeline of the user side circulating pipeline (110); a first temperature sensor (14) arranged at the water return pipeline of the user side circulating pipeline (110) and adjacent to the first control valve (13), and used for monitoring the temperature of the water return pipeline of the user side circulating pipeline (110). A first pressure transmitter (15) is arranged on the return pipe of the user-side circulation pipe (110) and adjacent to the first temperature sensor (14), and is used to monitor the pressure of the return pipe of the user-side circulation pipe (110); A first heat meter (16) is arranged on the return pipe of the user-side circulation pipe (110) and adjacent to the first pressure transmitter (15), and is used to monitor the heat flow through the return pipe of the user-side circulation pipe (110); A first water supplementing constant pressure device (17) is in communication with the user-side circulation pipe (110) to supplement water to the user-side circulation pipe (110); A heating circulation pump (18) is arranged on the return pipe of the user-side circulation pipe (110), and is used to drive the heating water in the user-side circulation pipe (110) to flow.

4. The coaxial casing heat extraction system for heating according to claim 2, characterized in that, The heat supply circulation pipeline (10) further comprises: A second control valve (19) is arranged on the inlet pipe of the user-side circulation pipe (110), and is used to open or close the inlet pipe of the user-side circulation pipe (110); A second temperature sensor (111) is arranged on the inlet pipe of the user-side circulation pipe (110) and adjacent to the second control valve (19), and is used to monitor the temperature of the inlet pipe of the user-side circulation pipe (110); A second pressure transmitter (112) is arranged on the inlet pipe of the user-side circulation pipe (110) and adjacent to the second temperature sensor (111), and is used to monitor the pressure of the inlet pipe of the user-side circulation pipe (110).

5. The coaxial casing heat extraction system for heating according to claim 2, characterized in that, The geothermal circulation pipeline (50) comprises: A geothermal circulation pipe (51) in communication with the geothermal well heat exchange device (40); A third electric valve (52) is arranged on the water inlet of the first heat absorbing end (22) and connected to the inlet pipe of the geothermal circulation pipe (51); A fourth electric valve (53) is arranged on the water inlet of the second heat absorbing end (32) and connected to the inlet pipe of the geothermal circulation pipe (51); The control unit is connected to the third electric valve (52) and the fourth electric valve (53) to switch the operation of the plate heat exchanger (20) or the heat pump unit (30).

6. The geothermal well coaxial casing heat extraction system of claim 5, wherein, The geothermal circulation pipeline (50) further comprises: A third temperature sensor (54) is arranged on the inlet pipe of the geothermal circulation pipe (51), and is used to monitor the temperature of the inlet pipe of the user-side circulation pipe (110); A third pressure transmitter (55) is arranged on the inlet pipe of the geothermal circulation pipe (51) and adjacent to the third temperature sensor (54), and is used to monitor the pressure of the inlet pipe of the geothermal circulation pipe (51).

7. The coaxial casing heat extraction system for heating according to claim 5, characterized in that, The geothermal circulation pipeline (50) further comprises: a second heat meter (56) disposed on the return pipe of the geothermal circulation pipe (51), the second heat meter (56) being configured to monitor heat flowing through the return pipe of the geothermal circulation pipe (51); a second water supplementing and pressure maintaining device (57) in communication with the geothermal circulation pipe (51) to supplement water to the geothermal circulation pipe (51); a geothermal circulation pump (58) disposed on the return pipe of the geothermal circulation pipe (51) and adjacent to the second heat meter (56), the geothermal circulation pump (58) being configured to drive geothermal water in the geothermal circulation pipe (51) to flow; a filter (59) disposed on the return pipe of the geothermal circulation pipe (51) and adjacent to the geothermal circulation pump (58), the filter (59) being configured to filter impurities in the geothermal water in the geothermal circulation pipe (51); a fourth temperature sensor (510) disposed on the return pipe of the geothermal circulation pipe (51) and adjacent to the filter (59), the fourth temperature sensor (510) being configured to monitor the temperature of the return pipe of the geothermal circulation pipe (51); a fourth pressure transmitter (511) disposed on the return pipe of the geothermal circulation pipe (51) and adjacent to the fourth temperature sensor (510), the fourth pressure transmitter (511) being configured to monitor the pressure of the return pipe of the geothermal circulation pipe (51).

8. The coaxial casing heat extraction system for heating according to claim 5, characterized in that, The inlet pipe and the return pipe of the geothermal circulation pipe (51) are connected with an adjusting pipe, and the geothermal circulation pipeline (50) further comprises: an electric adjusting valve (512) disposed on the adjusting pipe, the electric adjusting valve (512) being configured to adjust the flow rate of the adjusting pipe to control the flow rate of the geothermal water passing through the plate heat exchanger (20) or the heat pump unit (30).

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