Middle-deep layer hydrothermal type geothermal heating system and method

Abstract

The invention provides a medium-deep layer hydrothermal type geothermal heating system and method, and particularly relates to the field of energy and power engineering. The system comprises a geothermal well, a direct heat exchange device, a water source heat pump device and a user heating device. The geothermal well achieves mining and recharging of geothermal water, the direct heat exchange equipment supplies heat to the user heating equipment through primary heat exchange, the water source heat pump equipment supplies heat to the user heating equipment through secondary heat exchange and improvement of the secondary heat grade, and the user heating equipment achieves accurate heat supply to a heating building. Due to the application of the system, full utilization of geothermal water heat, safe and pollution-free same-layer equivalent recharge, great improvement of heat supply efficiency and automatic control of a heating system are achieved, many defects of a traditional utilization process are overcome, environment-friendly and efficient utilization of medium-deep geothermal water can be achieved, and the system has remarkable technical progress and practical value.

Description

Technical Field

[0001] This invention relates to the field of energy and power engineering, and more specifically, to a medium-deep hydrothermal geothermal heating system and method. Background Technology

[0002] Geothermal energy is a green, low-carbon, and renewable energy source, characterized by large reserves, wide distribution, cleanliness, environmental friendliness, stability, and reliability. Among these, medium-deep geothermal water resources, as an important type of geothermal energy, have high development and utilization potential. Medium-deep geothermal water resources are renewable and clean energy sources. Compared to fossil fuels, geothermal water resources are low-carbon, environmentally friendly, have high energy density, strong stability, low investment, and sustainable utilization. Therefore, medium-deep hydrothermal geothermal heating is an important way to achieve clean heating.

[0003] Currently, medium-deep hydrothermal geothermal heating systems have been widely used in northern my country and parts of central and eastern China. Their basic structure consists of geothermal wells, heat exchange equipment, heating pipe networks, and reinjection systems. The system typically extracts geothermal water from medium-deep aquifers through production wells, converts it into heat energy using plate heat exchangers or heat pump systems, and then supplies it to buildings for heating or domestic hot water. The utilized geothermal water is reinjected into the formation through reinjection wells to maintain reservoir pressure and thermal balance.

[0004] In engineering practice, a combination of direct heat exchange and heat pump-assisted heat exchange is often used, along with an intermediate water system, to achieve cascaded utilization of heat. The layout and operation of geothermal wells generally follow the principle of "pump-back balance and same-layer reinjection" to ensure resource sustainability. Before reinjection, geothermal water typically undergoes sedimentation, filtration, or simple water treatment to improve water quality and reduce the risk of blockage.

[0005] The control method of hydrothermal geothermal heating systems is still mainly based on traditional logic control, and the system operation relies on preset temperature or flow parameters for adjustment. Some projects have begun to adopt automation or centralized monitoring methods to achieve basic control of geothermal well operation and heat exchange equipment.

[0006] However, existing medium-deep geothermal heating systems still have many problems. These include: crude geothermal water utilization processes leading to high reinjection temperatures and insufficient extraction of heat energy; incomplete and equal-volume reinjection of extracted geothermal water within the same layer, resulting in water leakage or pollution; inadequate water treatment during reinjection, leading to changes in water quality and blockage of reinjection wells; insufficient geological exploration and assessment, resulting in decreased or even impossible reinjection capacity after a period of operation; unreasonable intermediate water system design leading to low efficiency of the heat pump system; lack of continuous monitoring and metering of extracted and reinjected geothermal resources, resulting in inadequate geothermal resource utilization management; and complex geothermal utilization processes with unreasonable control logic and methods. Summary of the Invention

[0007] The main objective of this invention is to provide a medium-deep geothermal heating system and method, which at least solves the problems of insufficient heat energy utilization in traditional geothermal heating systems. It achieves full utilization of geothermal heat, safe and pollution-free same-layer equal-volume reinjection, a significant improvement in heating efficiency, and automated control of the heating system, thereby realizing the environmentally friendly and efficient utilization of medium-deep geothermal water.

[0008] To achieve the above objectives, the present invention provides a medium-deep hydrothermal geothermal heating system and method.

[0009] In a first aspect, the present invention provides a medium-deep hydrothermal geothermal heating system, the system comprising: Geothermal wells are used for the extraction and reinjection of geothermal water; geothermal wells include production wells and reinjection wells. The direct heat exchanger is connected to the production well on the heating side to collect geothermal energy from the production well, and to the user's heating equipment on the heating side to supply the collected geothermal energy to the user's heating equipment after one heat exchange. The water source heat pump equipment connects its heating side to the heating side of the direct heat exchange equipment to collect geothermal energy after the first heat exchange of the direct heat exchange equipment. The water source heat pump equipment connects its heating side to the user's heating equipment to supply the collected geothermal energy after the first heat exchange to the user's heating equipment through a second heat exchange. User heating equipment is installed inside heated buildings to supply heat to the buildings.

[0010] Furthermore, a submersible pump is installed inside the production well to extract high-temperature geothermal water; a cyclone desander is installed between the submersible pump and the direct heat exchange equipment to remove sand from the high-temperature geothermal water.

[0011] Furthermore, the direct-heating heat exchange equipment includes a direct-heating plate heat exchanger and a hot water circulation pump; the heating-side inlet of the direct-heating plate heat exchanger is connected to a cyclone separator, and the heating-side inlet of the direct-heating plate heat exchanger is connected to the hot water circulation pump; the direct-heating plate heat exchanger is used to transfer the heat of the high-temperature geothermal water after sand removal to the heating return water to obtain low-temperature geothermal water and heating supply water, and the heating supply water is delivered to the user's heating equipment and provides heat to the user's heating equipment; the hot water circulation pump is used to regulate the flow rate of the heating return water entering the heating side of the direct-heating plate heat exchanger through frequency conversion; wherein, a first electric three-way regulating valve is installed at the heating-side inlet of the direct-heating plate heat exchanger; the first electric three-way regulating valve is used to regulate the flow rate of the high-temperature geothermal water after sand removal entering the heating side of the direct-heating plate heat exchanger.

[0012] Furthermore, the water source heat pump equipment includes: an intermediate plate heat exchanger, the heating-side inlet of which is connected to the heating-side outlet of the direct-heating plate heat exchanger; the intermediate plate heat exchanger is used to transfer the heat of low-temperature geothermal water to low-temperature intermediate water to obtain geothermal tailwater and high-temperature intermediate water; a water source heat pump unit, the evaporator side of which is connected to the heating side of the intermediate plate heat exchanger; the water source heat pump unit is used to enhance the heat of the high-temperature intermediate water and transfer it to the heating return water to obtain heating supply water, which is then delivered to the user's heating equipment and provides heat to the user's heating equipment; wherein, a second electric three-way regulating valve is installed at the heating-side inlet of the intermediate plate heat exchanger; the second electric three-way regulating valve is used to regulate the flow rate of low-temperature geothermal water entering the heating side of the intermediate plate heat exchanger; the heating-side outlet of the intermediate plate heat exchanger is connected to a reinjection well to allow geothermal tailwater to be reinjected into the reinjection well.

[0013] Furthermore, the water source heat pump equipment also includes: an intermediate circulation pump, which is connected to the heating side inlet of the intermediate plate heat exchanger; the intermediate circulation pump regulates the flow rate of the low-temperature intermediate water entering the heating side of the intermediate plate heat exchanger via frequency conversion; and a heat pump circulation pump, which is connected to the condenser side inlet of the water source heat pump unit; the heat pump circulation pump regulates the flow rate of the heating return water entering the condenser side of the water source heat pump unit via frequency conversion.

[0014] Furthermore, a filtration and pressurization module is installed between the intermediate heat exchanger and the reinjection well; the filtration and pressurization module includes: a filtration submodule, which is used to remove impurities from the geothermal tailwater; and a pressurization submodule, which is connected to the filtration submodule; the pressurization submodule is used to pressurize and reinject the impurity-removed geothermal tailwater when natural reinjection is difficult.

[0015] Furthermore, the system also includes a pipeline network, which comprises: pipelines, including geothermal water pipelines, intermediate water pipelines, and heating pipelines; a high-level expansion tank, located between the evaporator end of the water source heat pump unit and the heating-side inlet of the intermediate plate heat exchanger, with the bottom height of the high-level expansion tank required to be at least 0.5m higher than the highest point of the intermediate water pipeline; the high-level expansion tank relies on the gravity of the water in the high-level expansion tank to maintain the normal water level and static pressure of the intermediate water pipeline, thereby ensuring that the intermediate water pipeline is filled with water and does not become empty; a valve module, including multiple valves and a check valve; wherein, the multiple valves are located above the geothermal water pipelines and heating pipelines to control the flow direction of the corresponding fluids; the check valve is used to selectively pressurize the geothermal tailwater; and a constant pressure water supply device, connected to the heating pipelines; the constant pressure water supply device is used for water supply and pressure regulation of the heating pipelines.

[0016] Furthermore, the system also includes an automation control unit, which comprises: a monitoring module installed on the geothermal water pipes, intermediate water pipes, and heating pipes; the monitoring module includes multiple temperature sensors, multiple pressure sensors, multiple flow meters, and a heat meter; wherein, the multiple temperature sensors are used to monitor the temperature of all nodes in the pipes, the multiple pressure sensors are used to monitor the pressure of most nodes in the pipes, the multiple flow meters are used to monitor the flow rate of the main nodes in the pipes, and the heat meter is installed on the heating pipes to monitor the heat taken by the user's heating equipment; and low-voltage wiring, which connects the submersible pump, hot water circulation pump, intermediate circulation pump, etc. The system includes a heat pump circulating pump, a first electric three-way regulating valve, a second electric three-way regulating valve, a pressurization submodule, multiple valves, a check valve, a constant pressure water supply device, multiple temperature sensors, multiple pressure sensors, multiple flow meters, and a heat meter; low-voltage wiring is used to transmit monitoring signals and control commands; a control cabinet receives and integrates the low-voltage wiring, and automatically sends control commands to the submersible pump, hot water circulating pump, intermediate circulating pump, heat pump circulating pump, first electric three-way regulating valve, second electric three-way regulating valve, pressurization submodule, multiple valves, check valve, and constant pressure water supply device to switch operating modes according to the set logic.

[0017] Secondly, the present invention provides a method for medium-deep hydrothermal geothermal heating, the method comprising: Geothermal energy is extracted from production wells; The collected geothermal energy is supplied to users' heating equipment after undergoing a single heat exchange through direct heat exchange equipment. The geothermal energy collected after the first heat exchange is processed through a water source heat pump device, and after being subjected to a second heat exchange and improved in quality, it is supplied to the user's heating equipment. Heating is supplied to heated buildings through user heating equipment; The geothermal water after secondary heat exchange is reinjected into the reinjection well to achieve equal-volume reinjection.

[0018] This application provides a medium-deep geothermal heating system and method, which includes a geothermal well, a direct heat exchanger, a water source heat pump, and user heating equipment. The geothermal well enables the extraction and reinjection of geothermal water. The direct heat exchanger provides heat to the user heating equipment through primary heat exchange, and the water source heat pump provides heat to the user heating equipment through secondary heat exchange and improved secondary heat quality. The user heating equipment provides precise heating to the building. The application of this system achieves full utilization of geothermal heat, safe and pollution-free same-layer equal-volume reinjection, a significant improvement in heating efficiency, and automated control of the heating system. It solves many drawbacks of traditional utilization processes and enables the environmentally friendly and efficient utilization of medium-deep geothermal water, demonstrating significant technological progress and practical value. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A partial connection diagram of the medium-deep hydrothermal geothermal heating system provided in this application; Figure 2 A schematic diagram of the process for the medium-deep hydrothermal geothermal heating method provided in this application; Figure 3 A connection diagram of the medium-deep hydrothermal geothermal heating system provided in this application; Figure 4 This is a structural diagram of the pipeline provided in this application; Figure 5 This is a schematic diagram of the structure of the automation control unit provided in this application; Figure 6 A construction diagram of the medium-deep hydrothermal geothermal heating system provided in this application.

[0020] The above figures include the following reference numerals: 10. Geothermal well; 11. Production well; 12. Reinjection well; 111. Submersible pump; 13. Cyclone desander; 14. Filtration and pressurization module; 141. Filtration submodule; 142. Pressurization submodule; 20. Direct heat exchanger; 21. Direct heat plate heat exchanger; 22. Hot water circulation pump; 211. First electric three-way regulating valve; 30. Water source heat pump equipment; 31. Intermediate plate heat exchanger; 311. Second electric three-way regulating valve; 32. Water source heat pump unit; 33. Intermediate circulation pump; 34. 40. Heat pump circulating pump; 50. User heating equipment; 51. Piping network; 51. Pipes; 511. Geothermal water pipes; 512. Intermediate water pipes; 513. Heating pipes; 52. High-level expansion tank; 53. Valves; 531. Check valves; 54. Constant pressure water supply device; 60. Automation control unit; 61. Monitoring module; 611. Temperature sensor; 612. Pressure sensor; 613. Flow meter; 614. Heat meter; 62. Low-voltage wiring; 63. Control cabinet. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0023] In this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0024] The medium-deep hydrothermal geothermal heating system and method provided in this application include a geothermal well 10, a direct heat exchange device 20, a water source heat pump device 30, and a user heating device 40. The geothermal well 10 realizes the extraction and reinjection of geothermal water. The direct heat exchange device 20 provides heat to the user heating device 40 through primary heat exchange. The water source heat pump device 30 provides heat to the user heating device 40 through secondary heat exchange and improving the quality of secondary heat. The user heating device 40 realizes precise heating of the heated building.

[0025] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0026] Figure 1 A partial connection diagram of the medium-deep hydrothermal geothermal heating system provided in this application is shown below. Figure 1 As shown, this is a medium-deep hydrothermal geothermal heating system provided in this embodiment. The system includes: Geothermal well 10 is used for the extraction and reinjection of geothermal water; geothermal well 10 includes a production well 11 and a reinjection well 12; The direct heat exchanger 20 has its heating side connected to the production well 11 to collect geothermal energy from the production well 11, and its heating side connected to the user heating equipment 40 to supply the collected geothermal energy to the user heating equipment 40 after one heat exchange. The water source heat pump equipment 30 is connected to the heating side of the direct heat exchange equipment 20 to collect geothermal energy after the first heat exchange in the direct heat exchange equipment 20. The heating side of the water source heat pump equipment 30 is connected to the user heating equipment 40 to supply the collected geothermal energy after the first heat exchange to the user heating equipment 40 after a second heat exchange and improvement in quality. The user heating equipment 40 is installed in the heating building to supply heat to the building.

[0027] In specific implementation, the porosity of the filter pipes of production well 11 and reinjection well 12 shall not be less than 20% to ensure the efficiency of geothermal water extraction and reinjection. Furthermore, the insertion position of the filter pipes in both wells shall be basically consistent with the geothermal reservoir aquifer to ensure geothermal water reinjection within the same layer. After production well 11 and reinjection well 12 are completed, nitrogen gas shall be injected into the part above the water surface at the wellhead to replace the air in the well. After the replacement is completed, production well 11 and reinjection well 12 shall be sealed to reduce the contact between well water and air, effectively preventing the generation of microorganisms and changes in geothermal water quality.

[0028] Specifically, the heating system is a dual-source combined heating system. The heating side of the direct heat exchanger 20 is connected in series with the heating side of the water source heat pump 30 to achieve cascaded utilization of geothermal energy and full utilization of geothermal energy. Simultaneously, the heating side of the direct heat exchanger 20 is connected in parallel with the heating side of the water source heat pump 30 to achieve independent, mutual backup, and coordinated heating of the user's heating equipment 40 by the direct heat exchanger 20 and the water source heat pump 30. Furthermore, if any one of the heat exchangers fails, the other heat exchanger can operate independently to ensure uninterrupted heating. This design significantly improves the safety and reliability of the heating system.

[0029] Specifically, installing user heating equipment 40 in a heated building enables flexible and directional heating of the building.

[0030] Furthermore, by Figure 6 As shown, a submersible pump 111 is installed in the production well 11. The submersible pump 111 is used to extract high-temperature geothermal water. A cyclone desander 13 is installed between the submersible pump 111 and the direct heat exchange equipment 20. The cyclone desander 13 is used to remove sand from the high-temperature geothermal water.

[0031] In practice, the submersible pump 111 is a variable frequency pumping device that can flexibly adjust the amount of high-temperature geothermal water to be pumped and provide some pressure for the reinjection of geothermal tailwater; the cyclone separator 13 separates and effectively removes denser sand particles from the high-temperature geothermal water through cyclone action. This sand removal operation can effectively extend the service life of the pipeline network 50, thereby extending the working life of the entire system.

[0032] Furthermore, by Figure 3 and Figure 6As shown, the direct heat exchanger 20 includes a direct heat exchange plate 21 and a hot water circulation pump 22; the heating side inlet of the direct heat exchange plate 21 is connected to the cyclone sand separator 13, and the heating side inlet of the direct heat exchange plate 21 is connected to the hot water circulation pump 22; the direct heat exchange plate 21 is used to transfer the heat of the high-temperature geothermal water after sand removal to the heating return water to obtain low-temperature geothermal water and heating supply water, and the heating supply water is delivered to the user's heating equipment 40 and provides heat to the user's heating equipment 40; the hot water circulation pump 22 is used to regulate the flow rate of the heating return water entering the heating side of the direct heat exchange plate 21 through frequency conversion; wherein, a first electric three-way regulating valve 211 is provided at the heating side inlet of the direct heat exchange plate 21; the first electric three-way regulating valve 211 is used to regulate the flow rate of the high-temperature geothermal water after sand removal entering the heating side of the direct heat exchange plate 21.

[0033] In practice, the temperature of the heating water supply is calculated based on the outdoor temperature, which is determined by the climate compensator after calculating the outdoor temperature; while the temperature of the heating return water is determined by the heating water supply temperature, and the temperature difference between the two is preferably set at 10℃; the temperature of the heating water supply is usually 35-45℃, and the corresponding temperature of the heating return water is usually 25-35℃.

[0034] Specifically, regarding the outlet on the heating side and the inlet on the heating side of the direct-heating plate heat exchanger 21, considering the economic efficiency of the plate heat exchanger unit, the temperature difference between the two ends should be minimized. Maintain within the range of 2~3℃; specifically, the temperature of low-temperature geothermal water = +Heating return water temperature, among which .

[0035] Furthermore, by Figure 3 and Figure 6 As shown, the water source heat pump equipment 30 includes: an intermediate plate heat exchanger 31, the heating-side inlet of which is connected to the heating-side outlet of the direct-heating plate heat exchanger 21; the intermediate plate heat exchanger 31 is used to transfer the heat of low-temperature geothermal water to low-temperature intermediate water to obtain geothermal tailwater and high-temperature intermediate water; a water source heat pump unit 32, the evaporation side of which is connected to the heating side of the intermediate plate heat exchanger 31; the water source heat pump unit 32 is used to transfer the heat of high-temperature intermediate water to heating return water to obtain heating supply water, which is delivered to the user's heating equipment 40 and provides heat to the user's heating equipment 40; wherein, a second electric three-way regulating valve 311 is provided at the heating-side inlet of the intermediate plate heat exchanger 31; the second electric three-way regulating valve 311 is used to regulate the flow rate of low-temperature geothermal water entering the heating side of the intermediate plate heat exchanger 31; the heating-side outlet of the intermediate plate heat exchanger 31 is connected to the reinjection well 12 to allow the geothermal tailwater to be reinjected into the reinjection well 12.

[0036] In practice, the heating efficiency of the water source heat pump unit 32 is linked to the temperature of the high-temperature intermediate water entering its evaporation side. By steadily increasing the temperature of the high-temperature intermediate water as much as possible below the maximum allowable inlet water temperature on the evaporation side of the water source heat pump unit 32, the heating efficiency of the water source heat pump unit 32 can be significantly improved.

[0037] Specifically, the intermediate plate heat exchanger 31 has the same limitations as the direct-heating plate heat exchanger 21; regarding the outlet on the heating side and the inlet on the heating side of the intermediate plate heat exchanger 31, considering the economic efficiency of the plate heat exchanger unit, the temperature difference between the two ends should be minimized. Maintain within the range of 2~3℃; specifically, the geothermal tailwater temperature = + Low temperature intermediate water temperature, among which .

[0038] Furthermore, by Figure 6 As shown, the water source heat pump equipment 30 also includes: an intermediate circulation pump 33, which is connected to the heating side inlet of the intermediate plate heat exchanger 31; the intermediate circulation pump 33 regulates the flow rate of the low-temperature intermediate water entering the heating side of the intermediate plate heat exchanger 31 through frequency conversion; and a heat pump circulation pump 34, which is connected to the condenser side inlet of the water source heat pump unit 32; the heat pump circulation pump 34 regulates the flow rate of the heating return water entering the condenser side of the water source heat pump unit 32 through frequency conversion.

[0039] In practice, the flow rate of the low-temperature intermediate water entering the heating side of the intermediate heat exchanger 31 through the intermediate circulation pump 33 via frequency conversion is the same as the flow rate entering the evaporation side of the water source heat pump unit 32. Among them, the flow rates regulated by the two circulation pumps (intermediate water pump and heat pump circulation pump 34) that connect the evaporation side and condensation side of the water source heat pump respectively should be greater than the minimum flow rate requirement of the water source heat pump unit 32, and the rate of change of flow rate should be less than the rate of change that the water source heat pump unit 32 can withstand. This ensures that the unit can operate normally and does not cause protective shutdown due to insufficient flow or too rapid change of water flow.

[0040] In addition, the hot water circulation pump 22 and the heat pump circulation pump 34 are set independently and can be frequency-controlled, which can ensure that the direct heat exchanger 21 and the water source heat pump unit 32 can operate independently when the heating system is running. When any heating device fails, the other heating device can operate normally.

[0041] Furthermore, by Figure 6 As shown, a filtration and pressurization module 14 is provided between the intermediate plate heat exchanger 31 and the reinjection well 12; the filtration and pressurization module 14 includes: a filtration submodule 141, which is used to remove impurities from the geothermal tailwater; and a pressurization submodule 142, which is connected to the filtration submodule 141; the pressurization submodule 142 is used to pressurize and reinject the impurity-removed geothermal tailwater when natural reinjection is difficult.

[0042] In specific implementation, the filtration submodule 141 includes a coarse filtration device and a fine filtration device, which can powerfully remove impurities from the geothermal tailwater through a distributed design; the pressurization submodule 142 includes a first pressurization pump and a second pressurization pump. When natural reinjection cannot be achieved using the residual pressure of the submersible pump 111, the pressurization submodule 142 is activated to perform pressurization reinjection; the use of the first pressurization pump and the second pressurization pump is selected according to the pressure of the geothermal tailwater in the specific situation.

[0043] Furthermore, by Figure 3 , Figure 4 and Figure 6 As shown, the system also includes a pipe network 50, which includes: pipes 51, including geothermal water pipes 511, intermediate water pipes 512, and heating pipes 513; and a high-level expansion tank 52, located between the evaporator end of the water source heat pump unit 32 and the heating-side inlet of the intermediate plate heat exchanger 31. The bottom height of the high-level expansion tank 52 is required to be at least 0.5m higher than the highest point of the intermediate water pipes 512. The high-level expansion tank 52 maintains the intermediate water supply by the gravity of the water in it. The normal water level and static pressure of pipe 512 ensure that the intermediate water pipe 512 is filled with water and does not become empty; the valve module includes multiple valves 53 and a check valve 531; wherein, the multiple valves 53 are located on the geothermal water pipe 511 and the heating pipe 513 to control the flow direction of the corresponding fluids; the check valve 531 is used to selectively pressurize the geothermal tailwater; the constant pressure water supply device 54 is connected to the heating pipe 513; the constant pressure water supply device 54 is used to replenish and maintain the pressure of the heating pipe 513.

[0044] In practice, all pipes 51 are sealed together and between pipes 51 and components to form a closed system and maintain the airtightness of the system; the high-level expansion tank 52 has the maximum water pressure due to its location to passively replenish water to the intermediate water pipe 512, thereby ensuring that the intermediate water pipe 512 is filled with water and does not become empty.

[0045] Specifically, the constant pressure water supply device 54 includes a water supply pump and is equipped with a solenoid valve and a safety valve. When the heating pipe 513 is overpressurized, the solenoid valve is opened first to release pressure. If the pressure continues to rise and reaches the limit, the safety valve is opened to release pressure, ensuring that the pressure in the heating pipe 513 does not exceed the set value and protecting the heating pipe 513 and the equipment on it. When the pressure in the heating pipe 513 is lower than the set value, the water supply pump is activated to replenish the heating pipe 513 with softened water.

[0046] Specifically, the heating system has six valves 53, including a first valve 53 located at the pumping outlet of the production well 11, a second valve 53 located at the return water inlet of the reinjection well 12, a third valve 53 located on the heating return water branch near the user's heating equipment 40, a fourth valve 53 located on the heating supply water branch near the user's heating equipment 40, a fifth valve 53 connected in parallel with the coarse filter, and a sixth valve 53 connected in parallel with the fine filter; furthermore, the check valve 531 is connected in parallel with the first booster pump and the second booster pump.

[0047] Furthermore, by Figure 5 As shown, the system also includes an automation control unit 60, which includes: a monitoring module 61, which is installed on the geothermal water pipe 511, the intermediate water pipe 512, and the heating pipe 513; the monitoring module 61 includes multiple temperature sensors 611, multiple pressure sensors 612, multiple flow meters 613, and a heat meter 614; wherein, the multiple temperature sensors 611 are used to monitor the temperature of all nodes in the pipe 51, the multiple pressure sensors 612 are used to monitor the pressure of most nodes in the pipe 51, the multiple flow meters 613 are used to monitor the flow of the main nodes in the pipe 51, and the heat meter 614 is installed on the heating pipe 513 to monitor the heat taken by the user's heating equipment 40; and a low-voltage circuit 62, which connects the submersible pump 111, the hot water circulation pump 22, the intermediate circulation pump 33, and the heat pump circulation... The system includes a circulating pump 34, a first electric three-way regulating valve 211, a second electric three-way regulating valve 311, a pressurization submodule 142, multiple valves 53, a check valve 531, a constant pressure water supply device 54, multiple temperature sensors 611, multiple pressure sensors 612, multiple flow meters 613, and a heat meter 614; a low-voltage circuit 62 is used to transmit monitoring signals and control commands; a control cabinet 63 receives and integrates the low-voltage circuit 62, and automatically sends control commands for switching operating modes to the submersible pump 111, hot water circulating pump 22, intermediate circulating pump 33, heat pump circulating pump 34, first electric three-way regulating valve 211, second electric three-way regulating valve 311, pressurization submodule 142, multiple valves 53, check valve 531, and constant pressure water supply device 54 through the low-voltage circuit 62 according to the set logic.

[0048] Specifically, the monitoring module 61 preferably includes fifteen temperature sensors 611, including two at the wellhead of the geothermal well 10, four on both sides of the direct heat exchanger 21, four on both sides of the intermediate heat exchanger 31, two on the condenser side of the water source heat pump unit 32, one at the inlet of the coarse filter, and two on the heating supply and return branches of the heating pipe 513; preferably, the monitoring module 612 includes six pressure sensors 612, including two at the wellhead of the geothermal well 10, two on the heating supply and return branches of the heating pipe 513, one at the inlet of the coarse filter, and one at the inlet of the pressurization submodule 142; preferably, the monitoring module 613 includes four flow meters 613, including two at the wellhead of the geothermal well 10, one at the evaporator outlet of the water source heat pump unit 32, and one at the condenser inlet of the water source heat pump unit 32.

[0049] In practice, the setting logic of control cabinet 63 includes: Control of the first and second electric three-way regulating valves: The electric three-way regulating valves are adjusted based on the difference between the actual temperature on the heating side of the direct heating plate heat exchanger 21 and the intermediate plate heat exchanger 31 and the set value. The first electric three-way regulating valve 211 is adjusted according to the heating water temperature measured by the temperature sensor 611 at the heating side outlet of the direct heating plate heat exchanger 21. When the heating water temperature is higher than the set value, the flow rate into the bypass pipe is increased and the flow rate of the high-temperature geothermal water entering the direct heating plate heat exchanger 21 is reduced. When the heating water temperature is lower than the set value, the flow rate into the bypass pipe is reduced and the flow rate of the high-temperature geothermal water entering the direct heating plate heat exchanger 21 is increased. The second electric three-way regulating valve 311 is adjusted according to the high temperature of the intermediate water measured by the temperature sensor 611 at the heating side outlet of the intermediate heat exchanger 31. When the high temperature of the intermediate water is higher than the set value, the flow rate into the bypass pipe is increased and the flow rate of the high temperature intermediate water entering the intermediate heat exchanger 31 is reduced; when the high temperature of the intermediate water is lower than the set value, the flow rate into the bypass pipe is reduced and the flow rate of the high temperature intermediate water entering the intermediate heat exchanger 31 is reduced. Control of submersible pump 111: The operating frequency of submersible pump 111 is adjusted according to the geothermal tailwater temperature measured by temperature sensor 611 at the wellhead of reinjection well 12. When the geothermal tailwater temperature is higher than the set reinjection temperature, the frequency of submersible pump 111 is reduced; when the geothermal tailwater temperature is lower than the set reinjection temperature, the operating frequency of submersible pump 111 is increased. The preferred set reinjection temperature is 20℃. Control of hot water circulation pump 22: Hot water circulation pump 22 is adjusted according to the temperature difference between the supply and return water pipes on the heating side of direct heat exchanger 21; the heating supply water temperature is measured by the temperature sensor 611 at the heating side outlet of direct heat exchanger 21, and the heating return water temperature is measured by the temperature sensor 611 at the heating side inlet of direct heat exchanger 21. If the designed temperature difference is 10℃, the frequency of hot water circulation pump 22 is reduced when the temperature difference is less than 10℃, and the frequency of hot water circulation pump 22 is increased when the temperature difference is greater than 10℃. Control of heat pump circulation pump 34: Heat pump circulation pump 34 is adjusted according to the temperature difference of the supply and return water pipes connected to the condenser of water source heat pump unit 32; when the temperature difference is less than the set temperature difference, the frequency of heat pump circulation pump 34 is reduced, and when the temperature difference is greater than the set temperature difference, the frequency of heat pump circulation pump 34 is increased; wherein, the set temperature difference is also 10℃. Control of pressurization submodule 142: Pressurization submodule 142 adjusts the pressure of geothermal tailwater measured by pressure sensor 612 at the inlet of pressurization submodule 142; when the pressure is less than the set pressure, check valve 531 is closed to allow geothermal tailwater to enter pressurization submodule 142, and then the first pressurization pump or the second pressurization pump is selected and started according to the difference between the measured pressure and the set pressure; Control of multiple valves 53: The first to fourth valves 53 are normally open during system operation; while the fifth valve 53 connected in parallel with the coarse filter and the sixth valve 53 connected in parallel with the fine filter are normally closed during system operation to allow the geothermal tailwater to be filtered. The fifth and sixth valves 53 are only opened in case of system failure. Control of the constant pressure water supply device 54: Based on the comparison between the actual pressure measured by two pressure sensors 612 located on the heating water supply and return branches of the heating pipe 513 and the set pressure of the heating pipe 513, when the heating pipe 513 is over-pressurized, the solenoid valve is opened first to release pressure. If the pressure continues to rise and reaches the limit, the safety valve is opened to release pressure, ensuring that the pressure of the heating pipe 513 does not exceed the limit and protecting the heating pipe 513 and the equipment on it. When the pressure of the heating pipe 513 is lower than the set pressure value, the water supply pump is turned on to replenish the heating pipe 513 with softened water.

[0050] This automated control unit 60 enables real-time monitoring and precise control of various important parts of the heating system. By rationally setting up monitoring units and managing energy consumption, clarifying the control logic of each device, and making full use of intelligent means, the system can achieve efficient automated control to reach an unattended intelligent operation mode, thereby improving the overall efficiency of the system.

[0051] This system includes a geothermal well 10, a direct heat exchanger 20, a water source heat pump 30, and user heating equipment 40. The geothermal well 10 realizes the extraction and reinjection of geothermal water. The direct heat exchanger 20 supplies heat to the user heating equipment 40 through primary heat exchange, and the water source heat pump 30 supplies heat to the user heating equipment 40 through secondary heat exchange. The user heating equipment 40 achieves precise heating of the building. This system can fully utilize the heat of geothermal water, safely and pollution-free reinjection of equal amounts within the same floor, significantly improve heating efficiency, and automate the control of the heating system. It solves many drawbacks of traditional utilization processes and has significant technological progress and practical value.

[0052] Figure 2 A schematic diagram of the heating method for the medium-deep hydrothermal geothermal heating system provided in this application is shown below. Figure 2 The image shows a heating method for a medium-deep hydrothermal geothermal heating system provided in this embodiment. This method is applied to... Figure 1 The heating system of the medium-deep hydrothermal geothermal heating system in the embodiment includes the following method: Geothermal energy is extracted from production well 11; The collected geothermal energy is supplied to the user's heating equipment 40 after one heat exchange through the direct heat exchange equipment 20. The geothermal energy collected after the first heat exchange is processed by the water source heat pump equipment 30, and after the second heat exchange and quality improvement, it is supplied to the user's heating equipment 40. Heat is supplied to the building through the user's heating equipment 40; The geothermal water after secondary heat exchange is reinjected into reinjection well 12 to achieve equal-volume reinjection.

[0053] The following example illustrates this: First, well 10 (a hydrothermal geothermal well) will be drilled. Well 11 (a production well) will be a vertical well with a depth of 200-3000 meters (the specific depth will be determined based on actual needs; 3000 meters is used as an example here). The production section will be 1730-2950 meters deep, extracting hot water from the fractured pores of the Upper Miocene Lantian-Bahe Formation and the Upper Miocene Gaoling Group of the Neogene. The section from 0 to 450 meters will be the pump chamber section, with a borehole diameter of Φ444.5 mm. A Φ339.7 mm J55 grade oil casing will be installed, and the casing will be cemented with G-grade oil well cement throughout. The effective length of the pump chamber section will be no less than 420 meters. From 450 meters to the final depth, the borehole diameter must be no less than Φ241.3 mm. A Φ177.8 mm casing and filter pipe will be installed, with a filter pipe porosity of no less than 20%. The filter pipe's location should be basically consistent with the geothermal reservoir aquifer. Recharge well 12 is a directional well with a depth of 3043m (vertical depth 3000m). The first section, from 0 to 450m, requires a well diameter of at least Φ450mm, with Φ339.76mm J55 grade casing installed. The casing is cemented with G-grade oil well cement throughout, and the effective length of this first section is at least 420m. Starting 50m below 450m from this first section, the well is built up with an azimuth of 285.5° and a maximum inclination angle of 10.59°. From 450m to the final borehole depth of 3043m (vertical depth 3000m), the well diameter is required to be at least Φ241.3mm, with Φ177.8mm casing and a filter pipe installed. The filter pipe porosity is at least 20%, and its installation location should be basically consistent with the aquifer. In practice, the heating method involves extracting geothermal water (94℃) from production well 11 and utilizing it in stages through heat exchangers. Specifically, the high-temperature geothermal water is cooled to a low temperature of 47°C by direct heat exchanger 21. The heating side of direct heat exchanger 21 heats the return water from 35 / 25°C to obtain heating supply water from 45 / 35°C for use as a heat source for heating buildings. The low-temperature geothermal water (47°C) after passing through direct heat exchanger 21 enters intermediate heat exchanger 31 to heat the intermediate water from 22°C to 32°C. The heat carried by the high-temperature intermediate water is upgraded by water source heat pump unit 32 to heat the return water from 35 / 25°C to obtain heating supply water from 45 / 35°C for use as a heat source for heating buildings. The low-temperature geothermal water is cooled to below 20°C after passing through intermediate heat exchanger 31 to obtain geothermal tailwater. The geothermal tailwater is treated and finally reinjected into the geothermal water reinjection well 12 through pipelines.

[0054] This heating method achieves efficient recovery and utilization of geothermal heat energy, possesses the characteristics of safe and pollution-free same-layer equal-volume reinjection, and significantly improves heating efficiency and automation level. It overcomes many defects of traditional utilization methods, demonstrates the high efficiency and environmental friendliness of medium-deep geothermal water development and utilization, and has good promotion and application value.

[0055] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0056] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A medium-deep hydrothermal geothermal heating system, characterized in that, The system includes: Geothermal well (10), the geothermal well (10) is used for the extraction and reinjection of geothermal water; the geothermal well (10) includes a production well (11) and a reinjection well (12). A direct heat exchange device (20) is provided, wherein the heating side of the direct heat exchange device (20) is connected to the production well (11) to collect geothermal energy from the production well (11), and the heating side of the direct heat exchange device (20) is connected to the user heating equipment (40) to supply the collected geothermal energy to the user heating equipment (40) after one heat exchange. A water source heat pump device (30) is provided, wherein the heating side of the water source heat pump device (30) is connected to the heating side of the direct heat exchange device (20) to collect geothermal energy after the first heat exchange of the direct heat exchange device (20), and the heating side of the water source heat pump device (30) is connected to the user heating device (40) to supply the collected geothermal energy after the first heat exchange to the user heating device (40) after a second heat exchange and improvement in quality. The user heating equipment (40) is installed inside the heating building to supply heat to the building.

2. The medium-deep hydrothermal geothermal heating system according to claim 1, characterized in that, The production well (11) is equipped with a submersible pump (111), which is used to extract high-temperature geothermal water. A cyclone separator (13) is provided between the submersible pump (111) and the direct heat exchanger (20); the cyclone separator (13) is used to remove sand from the high-temperature geothermal water.

3. The medium-deep hydrothermal geothermal heating system according to claim 2, characterized in that, The direct heat exchange equipment (20) includes a direct heat plate heat exchanger (21) and a hot water circulation pump (22); The heating side inlet of the direct heat exchanger (21) is connected to the cyclone sand separator (13), and the heating side inlet of the direct heat exchanger (21) is connected to the hot water circulation pump (22). The direct heat exchanger (21) is used to transfer the heat of the high-temperature geothermal water after sand removal to the heating return water to obtain the low-temperature geothermal water and heating supply water. The heating supply water is delivered to the user heating equipment (40) and provides heat to the user heating equipment (40). The hot water circulation pump (22) is used to adjust the flow rate of the heating return water entering the heating side of the direct heat exchanger (21) by frequency conversion; The heating side inlet of the direct heat exchanger (21) is equipped with a first electric three-way regulating valve (211); the first electric three-way regulating valve (211) is used to regulate the flow rate of the high-temperature geothermal water after sand removal into the heating side of the direct heat exchanger (21).

4. The medium-deep hydrothermal geothermal heating system according to claim 3, characterized in that, The water source heat pump equipment (30) includes: Intermediate heat exchanger (31), the heating side inlet of the intermediate heat exchanger (31) is connected to the heating side outlet of the direct heat exchanger (21); the intermediate heat exchanger (31) is used to transfer the heat of the low temperature geothermal water to the low temperature intermediate water to obtain geothermal tailwater and the high temperature intermediate water. A water source heat pump unit (32) is provided, the evaporation side of which is connected to the heating side of the intermediate heat exchanger (31); the water source heat pump unit (32) is used to increase the heat of the high-temperature intermediate water and transfer it to the heating return water to obtain the heating supply water, which is then delivered to the user heating equipment (40) and provides heat to the user heating equipment (40); The intermediate heat exchanger (31) is equipped with a second electric three-way regulating valve (311) at its heating side inlet; the second electric three-way regulating valve (311) is used to regulate the flow rate of the low-temperature geothermal water into the heating side of the intermediate heat exchanger (31); the heating side outlet of the intermediate heat exchanger (31) is connected to the reinjection well (12) so that the geothermal tailwater is reinjected into the reinjection well (12).

5. The medium-deep hydrothermal geothermal heating system according to claim 4, characterized in that, The water source heat pump equipment (30) also includes: Intermediate circulation pump (33), the intermediate circulation pump (33) is connected to the heating side inlet of the intermediate heat exchanger (31); the intermediate circulation pump (33) adjusts the flow rate of the low-temperature intermediate water entering the heating side of the intermediate heat exchanger (31) by frequency conversion. A heat pump circulation pump (34) is connected to the condenser side inlet of the water source heat pump unit (32); the heat pump circulation pump (34) regulates the flow rate of the heating return water entering the condenser side of the water source heat pump unit (32) by frequency conversion.

6. The medium-deep hydrothermal geothermal heating system according to claim 5, characterized in that, A filtration and pressurization module (14) is provided between the intermediate plate heat exchanger (31) and the reinjection well (12); the filtration and pressurization module (14) includes: A filter submodule (141) is used to remove impurities from the geothermal tailwater; A pressurization submodule (142) is connected to the filtration submodule (141); the pressurization submodule (142) is used to pressurize and reinject the geothermal tailwater after impurity removal when natural reinjection is difficult.

7. The medium-deep hydrothermal geothermal heating system according to claim 6, characterized in that, The system also includes a pipe network (50), which comprises: Pipeline (51), the pipeline (51) includes geothermal water pipeline (511), intermediate water pipeline (512) and heating pipeline (513); An elevated expansion tank (52) is located between the evaporation end of the water source heat pump unit (32) and the heating side inlet of the intermediate plate heat exchanger (31). The bottom height of the elevated expansion tank (52) is required to be at least 0.5m higher than the highest point of the intermediate water pipe (512). The elevated expansion tank (52) relies on the gravity of the water in the elevated expansion tank (52) to maintain the normal water level and static pressure of the intermediate water pipe (512), thereby ensuring that the intermediate water pipe (512) is filled with water and does not become empty. The valve module includes multiple valves (53) and a check valve (531); wherein the multiple valves (53) are located above the geothermal water pipe (511) and the heating pipe (513) to control the flow direction of the corresponding fluids; the check valve (531) is used to selectively pressurize the geothermal tailwater. A constant pressure water supply device (54) is connected to the heating pipe (513); the constant pressure water supply device (54) is used for water supply and constant pressure of the heating pipe (513).

8. The medium-deep hydrothermal geothermal heating system according to claim 7, characterized in that, The system also includes an automation control unit (60), which includes: A monitoring module (61) is installed on the geothermal water pipe (511), the intermediate water pipe (512), and the heating pipe (513). The monitoring module (61) includes multiple temperature sensors (611), multiple pressure sensors (612), multiple flow meters (613), and a heat meter (614). The multiple temperature sensors (611) are used to monitor the temperature of all nodes in the pipe (51), the multiple pressure sensors (612) are used to monitor the pressure of most of the nodes in the pipe (51), the multiple flow meters (613) are used to monitor the flow rate of the main nodes in the pipe (51), and the heat meter (614) is installed on the heating pipe (513) to monitor the heat taken by the user heating equipment (40). The low-voltage circuit (62) connects the submersible pump (111), the hot water circulation pump (22), the intermediate circulation pump (33), the heat pump circulation pump (34), the first electric three-way regulating valve (211), the second electric three-way regulating valve (311), the pressurization submodule (142), multiple valves (53), the check valve (531), the constant pressure water supply device (54), multiple temperature sensors (611), multiple pressure sensors (612), multiple flow meters (613), and the heat meter (614); the low-voltage circuit is used to transmit monitoring signals and control commands. The control cabinet (63) receives and integrates the low-voltage circuit (62). According to the monitoring signal transmitted from the low-voltage circuit (62), the control cabinet (63) automatically sends the control command to the submersible pump (111), the hot water circulation pump (22), the intermediate circulation pump (33), the heat pump circulation pump (34), the first electric three-way regulating valve (211), the second electric three-way regulating valve (311), the pressurization submodule (142), multiple valves (53), the check valve (531), and the constant pressure water supply device (54) to switch the operating mode.

9. A heating method for a medium-deep hydrothermal geothermal heating system, characterized in that, The heating method is applied to the heating system according to any one of claims 1-8, and the heating method includes: Geothermal energy is extracted from the production well (11); The collected geothermal energy is supplied to the user's heating equipment (40) after one heat exchange through the direct heat exchange device (20); The geothermal energy collected after the first heat exchange is supplied to the user's heating equipment (40) through the water source heat pump equipment (30) after the second heat exchange and the quality is improved. Heating is supplied to the building through the user heating equipment (40); The geothermal water after secondary heat exchange is reinjected into the reinjection well (12) to achieve equal-volume reinjection.

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