Hydrothermal geothermal energy multi-stage utilization high-efficiency heating system

Abstract

The utility model discloses a kind of hydrothermal geothermal energy multistage utilization high-efficiency heating system, including heat source device, heat exchange device and recharge device. Heat source device contains geothermal production well, recharge well;Heat exchange device contains heat extraction unit, plate exchange indirect heat exchange unit, heat pump cascade utilization unit and heat network circulation heating unit, heat extraction unit contains submersible pump, cyclone sand remover, geothermal water relay pump, plate exchange indirect heat exchange unit includes primary heat exchanger, secondary heat exchanger, tertiary heat exchanger, heat pump cascade utilization unit includes heat pump unit and supporting circulation system, recharge device contains water treatment facilities and recharge pressurizing pump. The system is realized hydrothermal geothermal energy multistage high-efficiency utilization by "plate exchange multistage indirect heat exchange, high-low temperature heat pump series-parallel cascade utilization, geothermal tail water closed recharge", compared with traditional hydrothermal geothermal energy utilization, geothermal resource utilization is more sufficient, system energy efficiency is high, significantly reduce system operating cost, improve geothermal energy comprehensive utilization efficiency, reduce resource waste.

Description

Technical Field

[0001] This utility model relates to the field of geothermal energy utilization technology, specifically a hydrothermal type geothermal energy multi-stage utilization high-efficiency heating system. Background Technology

[0002] A Chinese utility model patent with publication number CN220135760U discloses a geothermal energy cascade utilization and circulation device, which is equipped with a production well and a reinjection well. A primary, secondary, tertiary, and quaternary heat exchanger are sequentially connected between the production and reinjection wells via pipelines. The geothermal water in the pumping pipe of the next-stage heat exchanger forms an insulation layer on the pumping pipe of the previous-stage heat exchanger, achieving cascade utilization of heat. However, configuring multiple pumping pipes for gradient heat exchange requires the separate installation of corresponding sand removal equipment. This not only increases operating costs but also significantly increases the effective contact area between the geothermal water and the external environment, thus severely increasing heat loss and resulting in low overall geothermal energy utilization efficiency. Utility Model Content

[0003] In view of this, the purpose of this utility model is to provide a high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy, so as to solve the technical problems mentioned in the prior art.

[0004] A high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy includes a production well and a reinjection well, and a heat exchange device installed on the connecting pipeline between the production well and the reinjection well. The heat exchange device includes: The geothermal energy heat extraction unit includes a submersible pump that is lowered into the casing of the production well to extract geothermal water, which is then transported to the heat exchange unit through a geothermal heating pipeline. The geothermal heating pipeline is equipped with a cyclone desander and a geothermal water relay pump. One end of the geothermal heating pipeline extends to the production well and connects to the submersible pump, while the other end of the geothermal heating pipeline is connected to the heat source input end of the primary heat exchanger. The geothermal indirect heat exchange unit includes a primary heat exchanger, a secondary heat exchanger, and a tertiary heat exchanger connected in series via pipes. The heat source output end of the tertiary heat exchanger is connected to a water treatment device via a geothermal tailwater pipe. A heat network circulating heating unit includes a heat circulation water supply pipe, a heat circulation return water pipe, a heat network return water circulation pump, and heat users. The inlet of the heat circulation return water pipe is connected to the outlet of the heat user. The outlet of the heat circulation return water pipe is connected to the cold source input end of the primary heat exchanger and the electric-driven low-temperature heat pump unit, respectively. The inlet of the heat circulation water supply pipe is connected to the cold source output end of the primary heat exchanger and the electric-driven high-temperature heat pump unit, respectively. The outlet of the heat circulation water supply pipe is connected to the inlet of the heat user. The heat network return water circulation pump is installed in the heat circulation return water pipe or the heat circulation water supply pipe.

[0005] Optionally, the cold source side of the secondary heat exchanger is connected to the evaporator side of the electrically driven high-temperature heat pump unit through the secondary heat exchange and high-temperature heat pump internal circulation pipe; The evaporator inlet and outlet of the electric-driven high-temperature heat pump unit form an annular channel with the cold input and output ends of the secondary heat exchanger through a secondary heat exchanger and a high-temperature heat pump internal circulation pipe. A high-temperature heat pump evaporator-side circulation pump is installed on the annular channel. The condenser inlet of the electrically driven high-temperature heat pump unit can be connected to the heat circulation return water pipe or the condenser outlet of the electrically driven low-temperature heat pump unit, and the condenser outlet of the electrically driven high-temperature heat pump unit is connected to the water outlet pipe of the heat pump cascade utilization unit.

[0006] Optionally, the cold source side of the three-stage heat exchanger is connected to the evaporator side of the electrically driven low-temperature heat pump unit through the three-stage heat exchanger and the internal circulation pipe of the low-temperature heat pump. The evaporator inlet and outlet of the electrically driven low-temperature heat pump unit form an annular channel with the cold input and output ends of the three-stage heat exchanger through a three-stage heat exchanger and a low-temperature heat pump internal circulation pipe. A low-temperature heat pump evaporator-side circulation pump is installed on the annular channel.

[0007] Optionally, the condenser inlet of the electrically driven low-temperature heat pump unit can be connected to the heat circulation return water pipe, and the condenser outlet of the electrically driven low-temperature heat pump unit can be connected to the condenser inlet of the electrically driven high-temperature heat pump unit or the heat circulation supply water pipe.

[0008] Optionally, the inlet and outlet temperatures of the evaporator side of the electrically driven low-temperature heat pump unit are lower than those of the electrically driven high-temperature heat pump unit. The condenser-side outlet temperature of the electrically driven low-temperature heat pump unit is lower than that of the electrically driven high-temperature heat pump unit, and the condenser-side inlet temperature of the electrically driven high-temperature heat pump unit is equal to or equal to the condenser-side outlet temperature of the electrically driven low-temperature heat pump unit.

[0009] Optionally, the heat circulation return water pipe is connected to the condenser side liquid inlet of the electric-driven low-temperature heat pump unit and the electric-driven high-temperature heat pump unit, and there is a second valve on the pipe connecting the condenser side liquid inlet of the electric-driven high-temperature heat pump unit to the heat circulation return water pipe. The low-temperature heat pump condenser side water outlet pipe of the electric-driven low-temperature heat pump unit is connected to the condenser side liquid inlet of the electric-driven high-temperature heat pump unit, and there is a first valve on the connecting pipe. The low-temperature heat pump condenser side water outlet pipe of the electric-driven low-temperature heat pump unit is connected to the water outlet pipe of the heat pump cascade utilization unit, and there is a third valve on the connecting pipe. The liquid outlet of the electrically driven high-temperature heat pump unit is connected to the water outlet pipe of the heat pump cascade utilization unit.

[0010] Optionally, the heat source outlet of the primary heat exchanger is connected to the heat source inlet of the secondary heat exchanger through the primary heat source outlet water pipe, and the heat source outlet of the secondary heat exchanger is connected to the heat source inlet of the tertiary heat exchanger through the secondary heat source outlet water pipe.

[0011] Optionally, the cold source outlet of the primary heat exchanger intersects with the water outlet pipe of the heat pump cascade utilization unit and is connected to the heat circulation water supply pipeline.

[0012] Optionally, a reinjection unit is provided between the reinjection well and the outlet of the tertiary heat exchanger, the reinjection unit comprising: The water treatment equipment has its inlet connected to the heat source outlet of the three-stage heat exchanger via a geothermal tailwater pipe, and its outlet connected to the reinjection well via a geothermal reinjection pipe. The geothermal reinjection pipe is equipped with a reinjection pressurization pump.

[0013] The beneficial effects that this utility model can produce include: 1. This utility model provides a high-efficiency multi-stage geothermal energy utilization heating system. This system utilizes geothermal energy through a three-stage plate heat exchanger combined with a series-parallel connection of high and low temperature heat pumps. Compared to traditional single-stage heat extraction combined with mixed-energy utilization, this system makes fuller use of geothermal resources, has higher energy efficiency, significantly reduces system operating costs, improves the overall utilization efficiency of geothermal energy, and reduces resource waste. Simultaneously, it matches high-temperature, medium-temperature, and low-temperature geothermal energy to different heat demands, avoiding energy waste and improving overall utilization efficiency by 15%-25% (based on a comparison with traditional mixed-energy utilization).

[0014] 2. In this invention, the operation modes of the high and low temperature heat pump can be flexibly adjusted by controlling the opening and closing of the condenser-side valve of the heat pump cascade utilization unit to adapt to the temperature requirements of different heat loads. While meeting basic heating needs, it also achieves on-demand temperature increases, avoiding excessive energy waste. Furthermore, the reinjection unit filters and intercepts impurities on the ground, ensuring that the geothermal water entering the reinjection well is clean and preventing well blockage. This extends the service life of the geothermal well while achieving water-free geothermal heat extraction. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a hydrothermal geothermal energy multi-stage utilization heating system according to this utility model; In the diagram: 1. Production well, 2. Reinjection well, 3. Submersible pump, 4. Cyclone desander, 5. Geothermal relay pump, 6. Primary heat exchanger, 7. Secondary heat exchanger, 8. Tertiary heat exchanger, 9. Water treatment equipment, 10. Reinjection booster pump, 11. High-temperature heat pump evaporator-side circulation pump, 12. Electric-driven high-temperature heat pump unit, 13. Low-temperature heat pump evaporator-side circulation pump, 14. Electric-driven low-temperature heat pump unit, 15. Heat network return water circulation pump, 16. Heat user, 17. Geothermal heating pipeline, 18. 19. Primary heat exchanger heat source outlet pipe; 20. Secondary heat exchanger heat source outlet pipe; 21. Geothermal tailwater pipe; 22. Geothermal reinjection pipe; 23. Secondary heat exchanger and high-temperature heat pump internal circulation pipe; 24. Tertiary heat exchanger and low-temperature heat pump internal circulation pipe; 25. Heat circulation water supply pipe; 26. Heat circulation return water pipe; 27. Low-temperature heat pump condenser side outlet pipe; 28. Heat pump cascade utilization unit outlet pipe; 29. ​​Primary heat exchanger cold source outlet pipe; 30. First valve; 31. Second valve; 32. Third valve. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1 As shown, this utility model provides a hydrothermal geothermal energy multi-stage utilization high-efficiency heating system, including a production well 1 and a reinjection well 2, and a heat exchange device installed on the connecting pipeline between the production well 1 and the reinjection well 2. The heat exchange device includes a geothermal energy heat extraction unit, a geothermal energy indirect heat exchange unit, and a heat network circulation heating unit. The geothermal energy extraction unit includes a submersible pump 3, a cyclone separator 4, a geothermal water relay pump 5, and a geothermal heating pipeline 17. One end of the geothermal heating pipeline 17 extends to the production well 1 and connects to the submersible pump 3, while the other end connects to the geothermal indirect heat exchange unit. The geothermal indirect heat exchange unit includes a primary heat exchanger 6, a secondary heat exchanger 7, and a tertiary heat exchanger 8 connected in series via pipelines. The heat source outlet of the primary heat exchanger 6 is connected to the heat source inlet of the secondary heat exchanger 7 via a primary heat source outlet pipe 18, and the heat source outlet of the secondary heat exchanger 7 is connected to the heat source inlet of the tertiary heat exchanger 8 via a secondary heat source outlet pipe 19. The cold source output end of the tertiary heat exchanger 8 is connected to the reinjection well 2 via a geothermal tailwater pipeline 20. This heating system utilizes geothermal resources more fully and reduces resource waste compared to the traditional single-stage heat extraction combined with mixed heat energy utilization heating method.

[0018] Furthermore, the heat network circulating heating unit includes a heat circulation water supply pipe 24, a heat circulation return water pipe 25, a heat network return water circulation pump 15, and heat users 16. The inlet of the heat circulation return water pipe 25 is connected to the outlet of the heat user 16, and the outlet of the heat circulation return water pipe 25 is connected to the cold source input end of the primary heat exchanger 6 and the electric-driven low-temperature heat pump unit 14, respectively. The inlet of the heat circulation water supply pipe 24 is connected to the cold source output end of the primary heat exchanger 3 and the electric-driven high-temperature heat pump unit 12, respectively. The outlet of the heat circulation water supply pipe 24 is connected to the inlet of the heat user 16, and the heat network return water circulation pump 15 is installed in the heat circulation return water pipe 25 or the heat circulation water supply pipe 24.

[0019] Furthermore, the heat source input temperature of the primary heat exchanger 6, secondary heat exchanger 7, and tertiary heat exchanger 8 decreases progressively along their flow direction. Therefore, to improve the overall utilization efficiency of geothermal energy, the subsequent secondary heat exchanger 7 and tertiary heat exchanger 8 are respectively equipped with an electrically driven high-temperature heat pump unit 12 and an electrically driven low-temperature heat pump unit 14. Figure 1 As shown, in this embodiment, during the heat exchange stage, the cold source is sequentially pumped into the cold source side of the electrically driven high-temperature heat pump unit 12, the electrically driven low-temperature heat pump unit 14, and the first-stage heat exchanger 6 via the heat network return water circulation pump 15. This allows for indirect heat exchange with the second-stage heat exchanger 7 and the third-stage heat exchanger 8, and direct heat exchange with the first-stage heat exchanger 6, thus achieving cascaded heat exchange of geothermal energy. The evaporator inlet and outlet of the electrically driven high-temperature heat pump unit 12 form an annular channel with the cold input and output ends of the second-stage heat exchanger 7 via the second-stage heat exchanger and the high-temperature heat pump internal circulation pipe 22. A high-temperature heat pump evaporator-side circulation pump 11 is installed on this annular channel. Similarly, the evaporator inlet and outlet of the electrically driven low-temperature heat pump unit 14 form an annular channel with the cold input and output ends of the third-stage heat exchanger 8 via the third-stage heat exchanger and the low-temperature heat pump internal circulation pipe 23. A low-temperature heat pump evaporator-side circulation pump 13 is installed on this annular channel. The inlet and outlet temperatures of the electrically driven low-temperature centrifugal heat pump unit 14 located on the cold source side of the tertiary heat exchanger 8 are lower than those of the electrically driven low-temperature centrifugal heat pump unit 14 located on the cold source side of the secondary heat exchanger 7. This, combined with the connection sequence between the heat circulation water supply pipe 24 and each stage of the heat exchanger, allows for the sequential connection of low-temperature, medium-temperature, and high-temperature media. This reduces energy waste caused by direct mixing of heat sources at different temperatures and minimizes temperature difference losses during sequential mixing of heat media within the heat circulation water supply pipe 24 (e.g., waste of geothermal energy collection when connecting a high-temperature heat source first, followed by a low-temperature heat source). This further improves the overall utilization efficiency of geothermal energy. Furthermore, the heat exchange efficiency can be adjusted by controlling the delivery pressure of the high-temperature heat pump evaporator-side circulation pump 11 and the low-temperature heat pump evaporator-side circulation pump 13.

[0020] In the heat exchange stage described above, the heat network return water after heat consumption on the user side is pumped into the condenser inlet of the electrically driven low-temperature heat pump unit 14 by the heat network return water circulation pump 15. The condenser outlet of the electrically driven low-temperature heat pump unit 14 can be selectively connected to the condenser inlet of the electrically driven high-temperature heat pump unit 12 or the outlet pipe 27 of the heat pump cascade utilization unit. The condenser outlet of the electrically driven low-temperature heat pump unit 14 and the condenser inlet of the electrically driven high-temperature heat pump unit 12 are connected through the low-temperature heat pump condenser side outlet pipe 26. The low-temperature heat pump condenser side outlet pipe 26 is equipped with a first valve 29 and a third valve 31. By controlling the opening and closing of the first valve 29 and the third valve 31, the heat network circulation water after being heated by the electrically driven low-temperature heat pump unit 14 can be selectively connected to the inlet of the electrically driven high-temperature heat pump unit 12 for further heating, or directly sent to the outlet pipe 27 of the heat pump cascade utilization unit and then merged into the heat circulation water supply pipeline for use. Furthermore, a second valve 30 is installed on the heat circulation return water pipe 25. By controlling the opening and closing of the first valve 29 and the second valve 30, the connection between the condenser inlet of the electrically driven high-temperature heat pump unit 12 and the condenser outlet of the electrically driven low-temperature heat pump unit 14 or the heat circulation return water pipe 25 can be controlled. Thus, the opening and closing states of the first valve 29, the second valve 30, and the third valve 31 can be adjusted based on the heat demand of the heat user 16. For example, when the heat load of the heat user 16 is small, the electrically driven low-temperature heat pump unit 14 can be shut down and the first valve 29 and the third valve 31 can be closed, while the second valve 30 is opened. This allows the heat medium obtained by the heat exchanger 7 to be heated by the electrically driven high-temperature heat pump unit 12 and then sent to the heat user 16 for use, thereby improving the system's energy efficiency. When the heat demand is large and the heat temperature is not high, the second valve 30 and the third valve 31 are opened, and the first valve 29 is closed, so that the large network circulating return water is connected to the inlet of the condenser of the electric-driven high-temperature heat pump unit 12 and the electric-driven low-temperature heat pump unit 14 respectively. After the large network circulating return water exchanges heat and is raised by the electric-driven high-temperature heat pump unit 12 and the electric-driven low-temperature heat pump unit 14, it is connected to the outlet pipe 27 of the heat pump cascade utilization unit from the outlet of the condenser of the electric-driven high-temperature heat pump unit 12 and the electric-driven low-temperature heat pump unit 14 respectively, and then flows into the heat circulation water supply pipeline 24 and is sent to the heat user 16 for use. When the heat demand is high and the heating temperature is high, close the second valve 30 and the third valve 31, and open the first valve 29. This allows the circulating water from the main network to first flow into the inlet of the condenser of the electrically driven low-temperature heat pump unit 14. After heat exchange and temperature increase by the electrically driven low-temperature heat pump unit 14, the circulating water enters the inlet of the condenser of the electrically driven high-temperature heat pump unit 12. After heat exchange and temperature increase by the electrically driven high-temperature heat pump unit 12, it is connected to the outlet pipe 27 of the heat pump cascade utilization unit and then flows into the heat circulation water supply pipeline 24 to be delivered to the heat user 16 for use. This ensures that the geothermal energy system operates in a high-efficiency zone throughout the entire heating period.

[0021] Furthermore, a water treatment device 9 is installed between the reinjection well 2 and the outlet of the tertiary heat exchanger 8. The heat source outlet of the tertiary heat exchanger 8 is connected to the inlet of the water treatment device 9 through the geothermal tailwater pipe 20. The outlet of the water treatment device 9 is connected to the reinjection well 2 through the geothermal reinjection pipe 21. The geothermal reinjection pipe 21 is equipped with a reinjection pressurization pump 10 to realize the sustainable utilization of geothermal energy by extracting heat without extracting water.

Claims

1. A high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy, comprising a production well (1) and a reinjection well (2), and a heat exchange device disposed on the connecting pipeline between the production well (1) and the reinjection well (2), characterized in that, The heat exchange device includes: The geothermal energy extraction unit includes a submersible pump (3) that is lowered into the casing of the production well (1) to extract geothermal water, which is then transported to the heat exchange unit through a geothermal heating pipeline (17). The geothermal heating pipeline (17) is equipped with a cyclone separator (4) and a geothermal water relay pump (5). One end of the geothermal heating pipeline (17) extends to the production well (1) and connects to the submersible pump (3). The other end of the geothermal heating pipeline (17) is connected to the heat source input end of the primary heat exchanger (6). The geothermal indirect heat exchange unit includes a primary heat exchanger (6), a secondary heat exchanger (7) and a tertiary heat exchanger (8) connected in series via pipes. The heat source output end of the tertiary heat exchanger (8) is connected to the water treatment equipment (9) via the geothermal tailwater pipe (20). The heating network circulating heating unit includes a heating circulating water supply pipe (24), a heating circulating water return pipe (25), a heating network return water circulation pump (15), and a heat user (16). The inlet of the heating circulating water return pipe (25) is connected to the outlet of the heat user (16). The outlet of the heating circulating water return pipe (25) is connected to the cold source input end of the first-stage heat exchanger (6) and the electric-driven low-temperature heat pump unit (14), respectively. The inlet of the heating circulating water supply pipe (24) is connected to the cold source output end of the first-stage heat exchanger (6) and the electric-driven high-temperature heat pump unit (12), respectively. The outlet of the heating circulating water supply pipe (24) is connected to the inlet of the heat user (16). The heating network return water circulation pump (15) is installed on the heating circulating water return pipe (25) or the heating circulating water supply pipe (24).

2. The high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy according to claim 1, characterized in that, The cold source side of the secondary heat exchanger (7) is connected to the electric-driven high-temperature heat pump unit (12) through the secondary heat exchange and high-temperature heat pump internal circulation pipe (22); The evaporator inlet and outlet of the electric-driven high-temperature heat pump unit (12) form an annular channel with the cold input end and output end of the secondary heat exchanger (7) through the secondary heat exchange and the high-temperature heat pump internal circulation pipe (22). A high-temperature heat pump evaporation side circulation pump (11) is installed on the annular channel. The condenser inlet of the electric-driven high-temperature heat pump unit (12) can be connected to the heat circulation return water pipe (25) or the condenser outlet of the electric-driven low-temperature heat pump unit (14), and the condenser outlet of the electric-driven high-temperature heat pump unit (12) is connected to the water outlet pipe (27) of the heat pump cascade utilization unit.

3. The high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy according to claim 1, characterized in that, The cold source side of the three-stage heat exchanger (8) is connected to the electric-driven low-temperature heat pump unit (14) through the three-stage heat exchanger and low-temperature heat pump internal circulation pipe (23). The evaporator inlet and outlet of the electric-driven low-temperature heat pump unit (14) form an annular channel with the cold input end and output end of the three-stage heat exchanger (8) through the three-stage heat exchanger and the low-temperature heat pump internal circulation pipe (23). A low-temperature heat pump evaporation side circulation pump (13) is installed on the annular channel. The condenser inlet of the electric-driven low-temperature heat pump unit (14) can be connected to the heat circulation return water pipe (25), and the condenser outlet of the electric-driven low-temperature heat pump unit (14) can be connected to the condenser inlet of the electric-driven high-temperature heat pump unit (12) or the water outlet pipe (27) of the heat pump cascade utilization unit.

4. A high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy according to any one of claims 2 and 3, characterized in that, The inlet and outlet temperatures of the electric-driven low-temperature heat pump unit (14) on the evaporation side are lower than those of the electric-driven high-temperature heat pump unit (12) on the evaporation side. The condenser-side outlet temperature of the electric-driven low-temperature heat pump unit (14) is lower than that of the electric-driven high-temperature heat pump unit (12), and the condenser-side inlet temperature of the electric-driven high-temperature heat pump unit (12) is equal to the condenser-side outlet temperature of the electric-driven low-temperature heat pump unit (14) or equal to the condenser-side inlet temperature of the electric-driven low-temperature heat pump unit (14).

5. A high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy according to claim 4, characterized in that, The hot circulation return water pipe (25) is connected to the condenser side liquid inlet of the electric-driven low-temperature heat pump unit (14) and the electric-driven high-temperature heat pump unit (12). The condenser side liquid inlet of the electric-driven high-temperature heat pump unit (12) is connected to the hot circulation return water pipe (25). There is a second valve (30) on the pipe. The low-temperature heat pump condenser side outlet pipe (26) of the electric-driven low-temperature heat pump unit (14) is connected to the condenser side liquid inlet of the electric-driven high-temperature heat pump unit (12), and there is a first valve (29) on the connecting pipe. The low-temperature heat pump condenser side outlet pipe (26) of the electric-driven low-temperature heat pump unit (14) is connected to the heat pump cascade utilization unit outlet pipe (27), and there is a third valve (31) on the connecting pipe. The liquid outlet of the electrically driven high-temperature heat pump unit (12) is connected to the water outlet pipe (27) of the heat pump cascade utilization unit.

6. A high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy according to claim 1, characterized in that, The heat source outlet of the primary heat exchanger (6) is connected to the heat source inlet of the secondary heat exchanger (7) through the primary heat source outlet pipe (18), and the heat source outlet of the secondary heat exchanger (7) is connected to the heat source inlet of the tertiary heat exchanger (8) through the secondary heat source outlet pipe (19).

7. A high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy according to claim 1, characterized in that, The primary heat exchanger (6) has a primary heat exchange cold source outlet pipe (28) that intersects with the heat pump cascade utilization unit outlet pipe (27) and is connected to the heat circulation water supply pipe (24).

8. A high-efficiency heating system for multi-stage utilization of hydrothermal geothermal energy according to claim 1, characterized in that, A reinjection unit is provided between the reinjection well (2) and the outlet of the tertiary heat exchanger (8), and the reinjection unit includes: Water treatment equipment (9), the inlet of the water treatment equipment (9) is connected to the heat source outlet end of the three-stage heat exchanger (8) through the geothermal tailwater pipe (20), and the outlet of the water treatment equipment (9) is connected to the reinjection well (2) through the geothermal reinjection pipe (21). The geothermal reinjection pipe (21) is equipped with a reinjection pressurization pump (10).

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