A system for coupling geotechnical energy storage to recover cooling water energy from a power plant

Abstract

The application relates to the technical field of energy storage, and discloses a system for coupling and recycling cooling water energy of a power plant by using a rock-soil energy storage system, which comprises a partitioned rock-soil energy storage subsystem, a heat pump unit and a dynamic weight heat flow scheduling module. The partitioned rock-soil energy storage subsystem comprises a high-temperature core heat storage area and a low-temperature coating heat storage area surrounding the periphery of the high-temperature core heat storage area. During heat storage, the dynamic weight heat flow scheduling module calculates a multi-target heat storage weight factor based on real-time electricity prices and system thermodynamic state parameters, determines a heat flow distribution ratio, intelligently distributes waste heat from the power plant to the low-temperature coating heat storage area and the high-temperature core heat storage area after being heated by the heat pump unit, and mixes the heat flows extracted from the two heat storage areas to form a heat source matched with the temperature of a target medium to supply the heat pump unit during heat extraction. The heat barrier structure formed by partitioned heat storage and the full-cycle dynamic optimization scheduling strategy solve the problems of serious heat loss of large-scale heat storage and low heat extraction efficiency.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to a system that utilizes a geotechnical energy storage system to couple and recover energy from power plant cooling water. Background Technology

[0002] The geothermal energy storage and recycling system is a technology that exchanges heat with the formation through a downhole heat exchanger. It develops and utilizes shallow geothermal energy in a "heat extraction without water extraction" manner, or uses geothermal material as an energy storage medium to store industrial waste heat, power plant waste heat, and abandoned electricity generated by fluctuations in wind and solar power generation.

[0003] In thermal power plants, a significant amount of energy is lost through the cooling water circulation system. Exhaust steam from the turbine condenses into water in the condenser, releasing a substantial amount of heat that is carried away by the circulating cooling water and ultimately released into the atmosphere through cooling towers. This heat loss accounts for approximately 50% of the total heat output of the power plant's boilers, resulting not only in enormous energy waste but also exacerbating the regional heat island effect.

[0004] Therefore, combining geotechnical energy storage technology with power plant cooling water circulation systems to recover this low-grade waste heat and use it to meet seasonal heating needs has become an important technological development direction. However, in current technological practices, large-scale cross-seasonal geotechnical energy storage of power plant waste heat still faces significant technical bottlenecks. When using conventional integrated geotechnical energy storage schemes, the large temperature gradient between the storage area and the surrounding ambient-temperature geotechnical environment causes the stored high-grade heat to continuously dissipate, severely reducing the long-term heat storage efficiency of the system. Furthermore, the existing system's operation and control strategies are often rather crude, such as starting and stopping heat pumps and other heating equipment based solely on a single electricity price signal, failing to comprehensively consider the system's thermodynamic efficiency under different operating conditions and the real-time status of the storage area, resulting in poor system economics. During the heat extraction phase, there is also a lack of refined management of energy quality, failing to achieve effective matching between the heat source and the heat pump unit's requirements, causing unnecessary energy quality losses and limiting the improvement of overall energy utilization.

[0005] Therefore, this invention proposes a system that utilizes a geotechnical energy storage system to couple and recover energy from power plant cooling water, in order to overcome the shortcomings of existing technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a system that utilizes a geotechnical energy storage system coupled with the recovery of cooling water energy from power plants. This system solves the problems of severe heat loss during large-scale cross-seasonal heat storage, low economic efficiency of the heat storage / extraction process, and low heat extraction efficiency when recovering and utilizing low-grade waste heat from power plants.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a system for recovering energy from power plant cooling water using a geotechnical energy storage system, comprising:

[0008] A zoned geotechnical energy storage subsystem, comprising a high-temperature core thermal storage zone and a low-temperature encased thermal storage zone geographically surrounding the high-temperature core thermal storage zone;

[0009] The heat pump unit is connected to the power plant cooling water circulation system and the high-temperature core heat storage area. The power plant cooling water circulation system includes a condenser for cooling the exhaust steam of the steam turbine and a cooling tower for cooling the circulating water, forming a cooling water flow that carries the waste heat from the condensation of the exhaust steam.

[0010] Sensor networks are used to collect real-time electricity prices and system operating parameters;

[0011] Actuator network is used to regulate heat flow path and flow rate;

[0012] The dynamic weighted heat flow scheduling module receives signals from the sensor network and controls the actuator network.

[0013] The dynamic weighted heat flow scheduling module is used for:

[0014] In thermal storage mode, based on the real-time electricity price and system thermodynamic state parameters collected by the sensor network, a multi-objective thermal storage weight factor is calculated. The heat flow distribution ratio is determined according to the multi-objective thermal storage weight factor. Based on the heat flow distribution ratio, the heat flow introduced from the power plant is simultaneously distributed to the low-temperature encased thermal storage area and the high-temperature core thermal storage area after being heated by the heat pump unit through the actuator network.

[0015] In heat extraction mode, the target medium temperature is calculated based on the real-time heat load of the terminal, and the heat flow extracted from the high-temperature core heat storage area and the low-temperature covered heat storage area is mixed to make the temperature of the mixed heat flow match the target medium temperature, and the mixed heat flow is used as the heat source of the heat pump unit.

[0016] Preferably, the buried pipe heat exchangers in the high-temperature core heat storage area constitute a first independent closed-loop network, and the buried pipe heat exchangers in the low-temperature encased heat storage area constitute a second independent closed-loop network physically isolated from the first independent closed-loop network; the dynamic weighted heat flow scheduling module independently controls the first and second independent closed-loop networks through the actuator network.

[0017] Preferably, the low-temperature coated thermal storage area is used to directly store low-grade thermal energy originating from the power plant's cooling water circulation system, and by increasing the temperature of the soil and rock within the low-temperature coated thermal storage area, a thermal barrier is formed for the high-temperature core thermal storage area, thereby reducing the temperature gradient between the high-temperature core thermal storage area and the surrounding soil and rock, and thus reducing the rate of loss of high-grade heat.

[0018] Preferably, the value of the heat flow allocation ratio is determined by the value of the multi-objective thermal storage weight factor, and the heat flow allocation ratio is the proportion of the flow rate directed to the high-temperature core thermal storage area heated by the heat pump unit to the total introduced flow rate.

[0019] Preferably, the multi-objective thermal storage weighting factor is obtained by weighted summation of economic factor, thermodynamic potential difference factor and energy storage capacity factor; the economic factor is determined based on the relationship between real-time electricity price and preset electricity price range, the thermodynamic potential difference factor is determined based on the relationship between heat source temperature and average temperature of high-temperature core thermal storage area, and the energy storage capacity factor is determined based on the relationship between average temperature of high-temperature core thermal storage area and upper and lower limits of design thermal storage temperature of high-temperature core thermal storage area.

[0020] Preferably, the system further includes:

[0021] An adaptive heat extraction circuit is provided, wherein a three-way proportional-integral regulating valve is provided on the adaptive heat extraction circuit;

[0022] In heat extraction mode, the dynamic weighted heat flow scheduling module adjusts the mixing ratio of heat flows extracted from the high-temperature core heat storage area and the low-temperature covered heat storage area by controlling the three-way proportional-integral regulating valve.

[0023] Preferably, the dynamic weighted heat flow scheduling module controls the three-way proportional-integral regulating valve through a closed-loop feedback control program. The target medium temperature calculated by the closed-loop feedback control program is the set value, and the real-time measurement value of the second temperature sensor installed downstream of the three-way proportional-integral regulating valve is the process variable.

[0024] Preferably, the sensor network includes:

[0025] A first temperature sensor used to measure the temperature of a heat source;

[0026] Multiple temperature sensors are used to measure the inlet and outlet water temperatures of each thermal storage zone;

[0027] Ground temperature sensors are installed inside the partitioned geotechnical energy storage subsystem;

[0028] A second temperature sensor for measuring the temperature of the mixed medium;

[0029] Electricity price signal receiver.

[0030] Preferably, the actuator network includes:

[0031] Multiple variable frequency circulating water pumps;

[0032] Multiple electrically operated regulating valves and on / off valves for switching fluid paths or regulating flow through each branch.

[0033] This invention also provides a method for recovering energy from power plant cooling water using a geotechnical energy storage system, the method comprising:

[0034] In thermal storage mode, real-time electricity prices and system thermodynamic state parameters are continuously collected to calculate multi-objective thermal storage weight factors, and the heat flow allocation ratio is determined based on the multi-objective thermal storage weight factors. Based on the heat flow allocation ratio, a portion of the heat flow from the cooling water circulation system of the power plant is controlled to directly enter the low-temperature encapsulated thermal storage area for storage, while another portion of the introduced heat flow is controlled to enter the evaporator of the heat pump unit, and the heat flow heated by the condenser of the heat pump unit is sent to the high-temperature core thermal storage area for storage.

[0035] In heat extraction mode, the target medium temperature required is calculated based on the real-time heat load of the terminal; based on the target medium temperature and the outlet temperatures of the high-temperature core heat storage area and the low-temperature covered heat storage area, the optimal heat source mixing ratio is calculated; and the heat flow extracted from the two heat storage areas is controlled to be mixed according to the optimal heat source mixing ratio, and the mixed heat flow is sent to the heat pump unit as a heat source to provide heat to the terminal.

[0036] This invention provides a system for recovering energy from power plant cooling water using a geotechnical energy storage system. It offers the following advantages:

[0037] 1. This invention improves the overall thermal efficiency of large-scale cross-seasonal thermal storage by setting up a zoned geotechnical energy storage subsystem, effectively reducing the loss of high-grade heat. The low-temperature encapsulated thermal storage zone in this system not only stores low-grade waste heat, but also forms an active thermal barrier for the high-temperature core thermal storage zone by increasing the geotechnical temperature of its own area. This thermal barrier reduces the temperature gradient between the high-temperature core thermal storage zone and the surrounding far-field geotechnical zone, physically inhibiting the rate of heat conduction outward, thereby sealing high-grade thermal energy in the core area for a longer period of time.

[0038] 2. This invention achieves dynamic optimization of the operating cost of the thermal storage process by designing a dynamic weighted heat flow scheduling module, thereby improving the overall economic efficiency of the system. The multi-objective thermal storage weight factor adopted by this module can comprehensively weigh the economic cost represented by the real-time electricity price, the operating efficiency represented by the thermodynamic potential difference, and the system state represented by the energy storage capacity. Based on this comprehensive judgment, the system can intelligently determine the heat flow distribution ratio, ensuring that power-consuming equipment such as heat pump units operate at the time with the most comprehensive benefits, thereby minimizing the total operating cost of the entire thermal storage cycle.

[0039] 3. This invention improves the energy cascade utilization efficiency and the operating performance of the heat pump unit in the heat extraction mode by constructing an adaptive coefficient-of-performance matching heat extraction loop. During heat extraction, the system does not directly use the high-grade heat source from the high-temperature core heat storage area, but precisely mixes it with the heat flow from the low-temperature encased heat storage area to generate a target medium temperature that just meets the requirements for efficient operation of the heat pump unit. This strategy avoids energy loss caused by using excessively high-temperature heat sources, ensures that the heat pump unit always operates in the optimal coefficient of performance range, and thus maximizes the overall heat extraction efficiency of the system.

[0040] 4. This invention improves the power plant's power generation efficiency by recovering and utilizing the waste heat from the condensation of exhaust steam, achieving bidirectional gains between the energy storage system and the heat source side. In heat storage mode, this system continuously extracts heat from the power plant's cooling water circulation system, effectively adding extra cooling capacity to the power plant. This reduces the temperature of the cooling water entering the cooling tower, thereby reducing the operating back pressure of the condenser, increasing the effective enthalpy drop of the turbine, and ultimately improving the overall power generation efficiency of the thermal power unit. Attached Figure Description

[0041] Figure 1 This is a system process diagram of the present invention;

[0042] Figure 2 This is a schematic diagram of the overall system structure of the present invention;

[0043] Figure 3 This is a flowchart of the dynamic coordinated thermal storage and adaptive heat extraction control logic of the present invention.

[0044] Figure 4 This is a schematic diagram of the partitioned geotechnical energy storage subsystem of the present invention.

[0045] Among them, 1. Boiler; 2. High-pressure heater; 3. Feed water pump; 4. Deaerator; 5. Low-pressure heater; 6. Condensate pump; 7. Condenser; 8. Steam turbine; 9. Generator; 10. Cooling tower; 11. Circulating pump one; 12. Heat exchanger; 13. Circulating pump two; 14. Heat pump main unit;

[0046] 10. Dynamic weighted heat flow scheduling module; 20. Zonal geotechnical energy storage subsystem; 21. High-temperature core thermal storage area; 22. Low-temperature coated thermal storage area. Detailed Implementation

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] See attached document Figure 2 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention. The present invention provides a geotechnical energy storage coupling system based on thermal grade zoning and full-cycle dynamic scheduling. This system is connected to the power plant cooling water circulation system, the geotechnical energy storage field, and the terminal heat user pipeline network. The system may include: a dynamic weighted heat flow scheduling module 10, a zoned geotechnical energy storage subsystem 20, and an adaptive heat extraction loop.

[0049] In the implementation environment of this invention, the system is connected to the cooling water circulation main pipeline of the condenser 7 of the thermal power plant through pipelines and valve groups to obtain the waste heat released during the condensation of exhaust steam of the turbine 8; the zoned geotechnical energy storage subsystem 20 is set in a site with heat storage geological conditions; the adaptive matching heat extraction loop connects the zoned geotechnical energy storage subsystem 20 to the heating network of the end heat user;

[0050] The dynamic weighted heat flow scheduling module 10, as the central control unit of the system, is responsible for executing the core control method of the system. The dynamic weighted heat flow scheduling module 10 receives signals from the sensor network at various parts of the system, including but not limited to the power plant cooling water temperature and flow rate, the temperature of each area of ​​the zoned geotechnical energy storage subsystem 20, and the real-time electricity price of the power grid. The dynamic weighted heat flow scheduling module 10 performs decision calculations based on the received signals and outputs control commands to the actuator network such as circulating pump 11, circulating pump 13, and regulating valve in the system.

[0051] A zoned geotechnical energy storage subsystem 20 is used to store heat recovered from a power plant in stages. The zoned geotechnical energy storage subsystem 20 is physically divided into at least two independent heat exchange zones. In this embodiment, it includes a high-temperature core heat storage zone 21 and a low-temperature covered heat storage zone 22.

[0052] The high-temperature core thermal storage area 21 is located in the central area of ​​the energy storage site, and the buried pipe heat exchangers inside are connected by independent pipeline junction points; this high-temperature core thermal storage area 21 is specifically used to store high-temperature thermal energy after its grade has been improved by the heat pump unit.

[0053] The low-temperature encased thermal storage area 22 is geographically located around the high-temperature core thermal storage area 21. The buried pipe heat exchanger inside is also connected to the junction point through another independent set of pipelines. The low-temperature encased thermal storage area 22 is used to directly store low-grade heat energy from power plant cooling water that has not been boosted by a heat pump, and to form thermodynamic isolation and insulation for the high-temperature core thermal storage area 21, so as to slow down the natural loss of heat to the surrounding rock and soil.

[0054] An adaptive heat extraction loop is used to extract heat from the zoned geotechnical energy storage subsystem 20 during the heating season, raise it to the temperature required by the user, and then deliver it to the outside. The adaptive heat extraction loop includes a heat pump unit 14 and a pipeline connecting its evaporator side to the zoned geotechnical energy storage subsystem 20. A key component is a three-way proportional-integral regulating valve located at the junction of the outlet pipeline of the high-temperature core heat storage area 21 and the outlet pipeline of the low-temperature covered heat storage area 22.

[0055] During the overall system operation, the dynamic weighted heat flow scheduling module 10 dynamically distributes the waste heat flow introduced from the power plant between the high-temperature core heat storage area 21 and the low-temperature covered heat storage area 22 based on real-time operating conditions and economic indicators during the non-heating season. During the heating season, this module 10 controls the three-way proportional-integral regulating valve in the adaptive heat extraction loop to achieve precise proportional mixing of the heat sources in the two heat storage areas, extracting energy with optimal efficiency to meet the heat load of end users.

[0056] See attached document Figure 1 , Figure 1 This is a schematic diagram of the overall structure of a cross-seasonal energy storage heating system integrated with the thermal system of a thermal power plant, according to an embodiment of the present invention.

[0057] In a typical thermal power plant, the power generation system is utilized, the core of which is a Rankine cycle steam power system. The main circulation process of this system begins with the condensate at the bottom of the condenser 7. After being pressurized by the condensate pump 6, the condensate enters the low-pressure heater 5 for preliminary preheating. Subsequently, the preheated condensate enters the deaerator 4, where it is heated to remove dissolved oxygen. At the same time, the makeup water from the tap water after water treatment is also incorporated into the main circulation here. The feedwater treated by the deaerator 4 is pressurized to a high-pressure state by the high-pressure feedwater pump 3 and sent to the high-pressure heater 2 for deep preheating. The preheated high-pressure feedwater enters the boiler 1, where it is heated into high-temperature and high-pressure superheated steam.

[0058] The high-temperature, high-pressure superheated steam is introduced into the turbine 8, impacting the turbine blades and driving the turbine 8 to rotate at high speed to perform work. The turbine 8 directly drives the generator 9 through the main shaft. The generator 9 uses the principle of electromagnetic induction to efficiently convert the mechanical energy output by the turbine 8 into electrical energy. The exhaust steam after performing work in the turbine 8 has a significantly reduced pressure and temperature and is discharged into the condenser 7 to be cooled into condensate, thus completing one full main power cycle.

[0059] The cooling circulation system exchanges heat with the main circulation at the condenser 7. The cooling water flowing from the bottom of the cooling tower 10 is pressurized by the circulation pump 11 and flows into the heat exchange pipes of the condenser 7. The cooling water flowing in the pipes absorbs a large amount of latent heat of vaporization released by the exhaust steam outside the pipes, causing the exhaust steam to condense into water, while the cooling water itself is heated to warm water (i.e., utilizing a low-grade heat source). In the traditional thermal power plant process, this heated hot water would be pumped to the top of the cooling tower 10 through valve V1 for spray cooling and then recycled. It is at this point that it is coupled with the thermal system of the thermal power plant, providing a resource utilization path for this part of the waste heat that would otherwise be directly discharged into the atmosphere.

[0060] In the first operating mode, the valve status is as follows: adjust the opening of V1, open V2, V3, V6, and V7, and close V4, V5, V8, V9, V10, and V11; the system performs direct storage of low-grade thermal energy from the power plant; when this mode is activated, a portion of the warm water heated in condenser 7 no longer flows to cooling tower 10, but is diverted and enters this energy storage system through the main inlet valve V2; this heat flow enters the buried pipe heat exchanger network of the low-temperature enclosed thermal storage zone 22 through valve V6. Essentially, the heat is introduced into an array of geothermal energy storage wells, ranging in depth from 100 to 300 meters, which constitute the heat storage area. Inside the energy storage wells, the circulating medium exchanges heat with the cooler geothermal material around the well through the pipe wall of the buried pipe, thereby releasing and storing the heat. The cooling water after heat release is collected through valve V7 and finally returned to the main pipeline of the power plant's cooling water circulation via the main outlet valve V3, where it flows into the water flowing to the cooling tower 10. This mode achieves low-cost, large-scale storage of power plant waste heat.

[0061] In the second operating mode, the valve status is as follows: adjust the opening of V1, open V2, V3, V4, V5, V8, and V9, and close V6, V7, V10, and V11. The system performs the heating and high-grade storage of waste heat from the power plant. In this mode, a portion of the warm water from the condenser 7 also enters the system through the inlet main valve V2, but it is guided to the evaporator side of the heat pump unit. Here, the cooling water releases heat to the heat pump working fluid, cools itself, and then returns to the main cooling water line of the power plant through the outlet main valve V3. This is an open heat source side loop. At the same time, in an independent energy storage side closed loop that is physically isolated from the power plant cooling water, the circulating medium is heated to a high temperature on the condenser side of the heat pump and sent to the geotechnical energy storage well constituting the high-temperature core heat storage area 21 through valve V8 for high-grade heat storage. Then, it returns to the heat pump condenser inlet through valve V9, completing one heating and heat storage cycle.

[0062] In the third operating mode, with valves V1, V8, V9, V10, and V11 open and V2, V3, V4, V5, V6, and V7 closed (i.e., the winter heating mode), this energy storage system is completely decoupled from the power plant's cooling circulation system. Both the inlet main valve V2 and the outlet main valve V3 are closed. At this time, the power plant's cooling water returns directly to the cooling tower 10 via valve V1 according to its original flow. This energy storage system operates independently, with the circulating medium driven by the internal circulation pump 13. Heat is extracted from the geotechnical energy storage wells that constitute the high-temperature core heat storage area 21 and the low-temperature covered heat storage area 22 (via pipelines V8 and V9 respectively), mixed, and sent as a heat source to the evaporator of the heat pump unit 14; after the heat pump unit improves the heat quality, it heats the user's heating circuit through its condenser side, and finally provides heat energy to the end user through valves V10 and V11; this series of working modes constitutes a complete technical solution that can realize the cross-seasonal storage and efficient utilization of industrial waste heat.

[0063] See attached document Figures 2-4 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention. The zoned geotechnical energy storage subsystem 20 of the present invention is an improvement on the conventional geotechnical energy storage field composed of multiple buried pipe heat exchange wells at the physical structure level. Its core lies in dividing a single homogeneous energy storage geotechnical body into independently controllable thermodynamic zones with different functions through the structured design of the pipeline system.

[0064] S201. The physical zoning of the energy storage well area is based on the pre-determined spatial topological location of the buried pipe heat exchange wells in various locations within the energy storage field. During the design phase, a group of buried pipe heat exchange wells located in the geographical center of the energy storage field is defined as the high-temperature core heat storage area 21; the remaining group of buried pipe heat exchange wells surrounding this core area and located in the peripheral zone is defined as the low-temperature encased heat storage area 22. This division ensures that the high-temperature core heat storage area 21 is completely encased by the low-temperature encased heat storage area 22 in the horizontal direction.

[0065] S202. All buried pipe heat exchangers (e.g., U-shaped buried pipes) within the high-temperature core heat storage area 21 constitute a first independent closed-loop pipe network. Specifically, the two ends of all U-shaped pipes in this area are connected to a dedicated high-temperature zone water supply main pipe and a dedicated high-temperature zone water return main pipe via branch pipes. These two main pipes serve as the only interface for fluid exchange between this independent pipe network and the system's main loop. Their connection and disconnection are managed by valve groups controlled by the dynamic weighted heat flow scheduling module 10. This connection method ensures that the circulating medium flowing through the high-temperature core heat storage area 21 forms an independent and controllable fluid loop within the pipe network.

[0066] S203 Similarly, all the buried pipe heat exchangers in the low-temperature enclosed heat storage area 22 constitute a second independent closed-loop pipe network that is physically isolated from the aforementioned first pipe network. The ports of all U-shaped pipes in this area are also connected to another dedicated low-temperature zone water supply main pipe and a dedicated low-temperature zone water return main pipe through branch pipes. The interfaces of this second independent pipe network are also independently controlled by the dynamic weighted heat flow scheduling module 10.

[0067] S204. Through the structured pipeline network design of configuring dedicated supply and return water mains for different areas, two physically isolated thermal storage units with independent flow paths and which can be scheduled separately or simultaneously are constructed within the same geotechnical energy storage field. As a result, the system can perform differentiated heat injection or extraction operations on the high-temperature core thermal storage area 21 and the low-temperature covered thermal storage area 22.

[0068] S205. An important function of this partitioned structure is that the low-temperature encased thermal storage zone 22 forms an effective thermal barrier for the high-temperature core thermal storage zone 21. Under thermal storage conditions, the low-grade heat injected into the low-temperature encased thermal storage zone 22 will raise the temperature of the rock and soil in its area, thereby reducing the temperature gradient between the high-temperature core thermal storage zone 21 and the surrounding rock and soil. According to the basic law of heat conduction, the heat flux density is proportional to the temperature gradient. Therefore, this structure can significantly reduce the rate of loss of high-grade heat stored in the high-temperature core thermal storage zone 21 to the far-field rock and soil, and improve the effective energy storage cycle and storage efficiency.

[0069] See attached document Figure 2 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention.

[0070] The piping system of S211, the high-temperature core heat storage area 21, is the first independent closed-loop pipe network. Its internal structure is designed to achieve efficient and rapid access to high-grade thermal energy. This design aims to minimize hydraulic resistance and heat loss during fluid transport and maximize heat exchange power per unit time.

[0071] S212. In a preferred embodiment, the buried pipe heat exchangers in the high-temperature core heat storage area 21 are connected in a completely parallel manner; specifically, a dedicated high-temperature zone water supply main pipe and a dedicated high-temperature zone water return main pipe are arranged in parallel; the inlet end of each buried pipe heat exchanger in this area is connected to the high-temperature zone water supply main pipe through an independent branch pipe, and its outlet end is connected to the high-temperature zone water return main pipe through an independent branch pipe.

[0072] S213. This fully parallel pipe network structure has a significantly lower overall hydraulic resistance. This characteristic enables the circulating pump 13 to drive a large amount of circulating medium through the entire high-temperature core heat storage area 21 with reasonable energy consumption, achieving high flow rate and low head operation. High flow rate is a prerequisite for achieving high heat exchange power, thus providing a fluid dynamic basis for the rapid injection and extraction of high-grade heat energy.

[0073] S214. When storing heat in the high-temperature core heat storage area 21, the high-temperature circulating medium from the condenser side of the heat pump unit is simultaneously distributed to all parallel buried pipe heat exchangers through the high-temperature zone water supply main. This distribution method enables the high-temperature medium to exchange heat with the largest area of ​​soil and rock in the area at the same time, greatly increasing the instantaneous heat exchange area, thereby realizing rapid heat storage. When extracting heat, this parallel structure also allows the circulating medium to absorb heat from all buried pipe heat exchangers simultaneously and in parallel and flow into the high-temperature zone return water main, ensuring a rapid and sufficient heat supply to the heat pump evaporator side.

[0074] S215. In some other embodiments, in order to adapt to larger-scale or irregularly shaped well site layouts and to better balance the flow distribution among the loops, the pipe network of the high-temperature core heat storage area 21 can also adopt a series-parallel connection method; for example, several adjacent buried pipe heat exchangers can be connected in series to form a basic heat exchange unit group, and then multiple such unit groups can be connected in parallel; this design increases the local flow resistance through the series part, which helps to achieve natural hydraulic balance between different parallel branches, but its overall design principle is still to ensure large flow and high heat exchange efficiency.

[0075] S216. Regardless of the specific internal connection method adopted, the pipe network of the high-temperature core heat storage area 21 is connected to the main circuit of the system through its dedicated supply and return water mains. The control valves set at these two interfaces (such as valves V8 and V9 in the attached diagram) are precisely controlled by the dynamic weighted heat flow scheduling module 10 to ensure that the area can be used as an independent heat storage unit, participating in or leaving the system cycle according to system instructions, so as to realize the independence and controllability of its functions.

[0076] See attached document Figure 2 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention.

[0077] S221, the piping system of the low-temperature covered thermal storage area 22, as the second independent closed-loop pipe network, is designed to receive and store large-scale low-grade thermal energy economically and efficiently, while providing thermodynamic insulation for the high-temperature core thermal storage area 21 at the same time.

[0078] S222. In a specific embodiment, the buried pipe heat exchangers inside the low-temperature enclosed heat storage zone 22 are also connected in parallel. The dedicated low-temperature zone water supply main and low-temperature zone water return main receive the circulating medium from the main circuit of the system. Each buried pipe heat exchanger in this zone is independently connected in parallel between these two main pipes. This pipe network structure ensures that the circulating medium can be evenly distributed to each heat exchanger widely distributed in the peripheral area.

[0079] S223. The parallel pipe network has a low overall hydraulic resistance, which is crucial for receiving large flow and low temperature difference heat sources from power plant cooling water. It allows the system to drive a large amount of circulating medium through the entire low temperature covered heat storage area 22 with low pumping energy consumption, thereby achieving continuous heat exchange with the soil and rock over a large heat exchange area and meeting the requirements for receiving large-scale low-grade heat energy.

[0080] S224. A key function of this pipeline design is to enable the low-temperature coated thermal storage zone 22 to form an effective thermal barrier for the high-temperature core thermal storage zone 21. The principle is that, under thermal storage conditions, the low-grade heat injected into the low-temperature coated thermal storage zone 22 reduces the average temperature of the surrounding soil and rock. The temperature rises, exceeding the natural constant temperature of the far-field soil and rock; according to the law of heat conduction, the heat flux density lost from the high-temperature core reservoir 21 is proportional to its temperature gradient with the surrounding medium; due to the presence of the heated low-temperature enveloped reservoir 22, the main interface for heat transfer from the high-temperature core reservoir 21 changes from the far-field soil and rock to this region; therefore, the main driving temperature difference for heat loss changes from... Transform into ,in, The average temperature representing the high-temperature core thermal storage zone 21; This represents the average temperature of the low-temperature covered thermal storage zone 22 after it has been heated by receiving low-grade heat. This represents the natural constant temperature of the far-field soil and rock unaffected by thermal storage activity; because Therefore, the temperature gradient is significantly reduced, thereby effectively reducing the rate of loss of high-grade thermal energy in the high-temperature core thermal storage area 21.

[0081] S225, the pipeline network of the low-temperature coated thermal storage area 22 is an independent thermal storage unit, and is connected to the main circuit of the system through its dedicated supply and return water mains and interface valves (such as valves V6 and V7 in the attached diagram). The dynamic weighted heat flow scheduling module 10 can independently control the flow rate of the circulating medium entering the area, and even completely shut down the circuit under specific operating conditions. This independent controllability is the structural basis for realizing the dynamic and continuous adjustment of the system between different thermal storage strategies.

[0082] See attached document Figure 2 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention.

[0083] S301, the dynamic weighted heat flow scheduling module 10 is the technical carrier for implementing the control method of the present invention. It consists of a central processing unit, a sensor network, and an actuator network. The central processing unit is the core of the module. Its specific implementation can be a programmable logic controller (PLC), a controller station of a distributed control system (DCS), or an industrial computer with high reliability and real-time performance. The central processing unit has the control algorithm of the present invention embedded in it. It is responsible for receiving and processing real-time data from the sensor network, performing decision calculations, and generating control commands to output to the actuator network.

[0084] S302. The sensor network is the sensing foundation of this system, used to comprehensively monitor the system's thermodynamic state, operating conditions, and external environmental parameters; this network includes, but is not limited to, the following measuring devices:

[0085] Multiple temperature sensors are deployed at key nodes of the system to obtain temperature data; these include sensors installed on the main pipe into which the power plant's cooling water enters the system to measure the temperature of the heat source. The first temperature sensor; multiple temperature sensors installed on the supply and return water mains of the high-temperature core thermal storage area 21 and the low-temperature covered thermal storage area 22 to measure the inlet and outlet water temperatures of each area. These data can be used to calculate... and Multiple geothermal sensors pre-buried at different depths and locations within the energy storage site measure data, and the weighted average of these measurements yields the average temperature characterizing the energy storage system's state. and A second temperature sensor, installed downstream of the three-way proportional-integral control valve in the adaptive matching heat extraction circuit and before the evaporator inlet of the heat pump unit 14, is used to measure the temperature of the mixed medium; and a sensor is used to measure the outdoor ambient temperature. Weather sensors;

[0086] S303, the sensor network also includes flow sensors, which are deployed in the main pipelines and key branches of the system to measure the flow rate of the circulating medium through each part, such as measuring the total inlet flow rate. The primary flow sensor is used; in addition, pressure sensors are installed at the inlet and outlet of key equipment such as circulating water pumps to monitor the hydraulic status of the system and provide a basis for equipment operation protection; and to receive real-time time-of-use electricity prices from the power grid. The electricity price signal receiver is also included in the network. Its specific implementation can be a data interface module that communicates with the power grid data center or a third-party energy data service provider through network protocols (such as Modbus-TCP / IP, OPC-UA).

[0087] S304, the actuator network is the specific execution unit of the control commands of this system, responsible for the precise delivery and distribution of fluids within the system; this network includes multiple variable frequency circulating water pumps controlled by the central processing unit, which can continuously regulate the flow rate of the circulating medium by adjusting their operating frequency; this network also includes multiple electric regulating valves and on / off valves, which are installed at various branches and nodes of the pipeline network to switch fluid paths or regulate the flow rate through each branch.

[0088] S305. In this actuator network, a key component is a three-way proportional-integral regulating valve in the adaptive matching heat extraction circuit. This valve is installed at the junction of the return water main of the high-temperature core heat storage area 21 and the return water main of the low-temperature covered heat storage area 22. Its function is to precisely adjust the mixing ratio of the two return waters according to the continuous control signal (e.g., 4-20mA current signal or 0-10V voltage signal) output by the central processing unit. Through precise control of the valve opening, the central processing unit can achieve adaptive matching of the heat source quality under the heat extraction conditions during the heating season.

[0089] The core software of the S311 dynamic weighted heat flow scheduling module 10 is embedded in its internal central processing unit, forming an automated control logic. This control logic is executed cyclically with a preset scanning cycle (e.g., 1-5 seconds). Through a structured program framework, it realizes the reception of sensor data, decision calculation, and instruction output to the actuator network.

[0090] S312. Within a complete control cycle, the software core first executes data acquisition and preprocessing tasks; it reads real-time data from all measurement points in the sensor network through the input / output interface, including but not limited to heat source temperature. Average temperature of each thermal storage area and Electricity price and user heat load The program performs validity checks and digital filtering on the collected raw data to eliminate random noise interference and provide a stable and reliable data foundation for subsequent decision-making operations.

[0091] S313. After data processing is complete, the control logic enters the top-level operation mode judgment module; this module determines the operation mode based on preset calendar information (e.g., defining the heating season as November to March of the following year) and outdoor ambient temperature. Whether the temperature is below a certain threshold (e.g., 10°C) or a received manual instruction determines whether the system should currently be in the non-heating season heat storage mode or the heating season heat extraction mode; the result of this judgment will determine the program flow to the next specific control subroutine.

[0092] S314. If the system is in thermal storage mode, the control logic will call the non-heating season dynamic coordination thermal storage algorithm module; this module will adjust the real-time input... , and Parameters such as the thermal storage weighting factor, which will be detailed later in this invention, will be applied. The calculations were performed to determine the proportion of heat flow distribution to the high-temperature and low-temperature thermal storage circuits. .

[0093] S315. If the system is in heating mode, the control logic calls the heating season adaptive matching heating algorithm module; this module is based on real-time user heat load. Based on the built-in heat pump performance curve, the optimal target evaporation temperature is calculated. And based on actual measurements and Furthermore, the optimal heat source mixing ratio required to achieve the target temperature was calculated. ;

[0094] S316. After the decision calculation is completed, the software core enters the control output generation and execution stage; the key control parameters calculated in the previous step (such as...) are then processed. or This is translated into specific operational instructions for the actuator network; for example, in thermal storage mode, the allocation ratio is... This translates into specific opening commands for the electric regulating valves on the corresponding pipelines; in heat extraction mode, it will adjust the mixing ratio. As a setpoint, a closed-loop controller (e.g., a PID controller) is driven, which uses the measured temperature downstream of the three-way proportional-integral control valve as the process variable. By continuously adjusting the opening of the three-way proportional-integral regulating valve to the target set point, the heat source is precisely mixed on demand; at the same time, the program at this stage is also responsible for issuing the corresponding frequency command to the variable frequency circulating water pump according to the required total flow rate.

[0095] S317. The entire process from data acquisition to command output constitutes a complete control scan cycle. The high-frequency repetition of this cycle ensures that the system can respond quickly, continuously, and smoothly to changes in internal and external operating conditions, thereby achieving dynamic optimization operation throughout the entire cycle.

[0096] See attached document Figure 2 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention.

[0097] S401. After the system is started, the core dynamic weighted heat flow scheduling module 10 of the control method of the present invention enters a continuous and periodic state perception and data processing preparation stage; this stage provides a real-time, accurate and reliable data foundation for the implementation of all subsequent advanced control strategies.

[0098] S402. In each control cycle, the dynamic weighted heat flow scheduling module 10 first collects a series of real-time parameters characterizing the internal and external states of the system through its sensor network; these parameters include at least:

[0099] The real-time temperature of the heat source medium entering this system from the power plant's cooling water circulation system;

[0100] The total real-time flow rate of the heat source medium available for use by this system from the power plant;

[0101] Real-time temperature of the circulating medium returning from the high-temperature core thermal storage zone 21;

[0102] Real-time temperature of the circulating medium returning from the low-temperature coated thermal storage zone 22;

[0103] The real-time outdoor air temperature of the system's operating location;

[0104] Real-time time-of-use electricity prices obtained through an electricity price signal receiver;

[0105] Real-time heat load demand at the terminal level, obtained from metering devices on the heat user side during the heating season.

[0106] S403. For the acquired raw electrical signal, the central processing unit first performs an validity check, such as determining whether the converted physical quantity value is within the preset reasonable range, in order to identify and eliminate obvious abnormal data points caused by sensor malfunction or signal transmission interference.

[0107] S404. Subsequently, a digital filtering algorithm is applied to the data that has passed the validity check. In one embodiment, a moving average filter or a low-pass filter algorithm can be used to process the data of multiple consecutive sampling periods to smooth out high-frequency noise and random fluctuations in the data and extract stable values ​​that can reflect the changing trend of the real physical process.

[0108] S405. For some key state parameters that are not directly measured, they are obtained through calculation; for example, the average temperature of the high-temperature core thermal storage zone, which characterizes the thermodynamic state of the energy storage body. and the average temperature of the low-temperature coated thermal storage area It is calculated by weighted averaging the filtered readings of multiple ground temperature sensors (number n) deployed in their respective areas; the calculation formula can be expressed as:

[0109] ;

[0110] in: This represents the calculated regional average temperature, i.e. or ; It is the first in the region Real-time temperature readings from a single ground temperature sensor; Is assigned to the first The weighting coefficients for each sensor can be preset based on the representativeness of the sensor's spatial location or its burial depth, and the sum of all weighting coefficients satisfies the following conditions: .

[0111] S406. After the above-mentioned acquisition, verification, filtering and calculation processing, the set of high-confidence state parameters will be updated and stored in the internal data register of the central processing unit. These data serve as the unified input for all subsequent decision-making algorithm modules in the current control cycle, ensuring the real-time performance and accuracy of the system control decisions.

[0112] Example 1: Refer to Appendix Figure 2 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention.

[0113] S411. When the dynamic weighted heat flow scheduling module 10 determines that the system is in the heat storage mode during the non-heating season, it will activate the dynamic coordinated heat storage control method. The core of this method is to replace the traditional discrete switching operation between different heat storage modes with a continuous and parallel dynamic heat flow allocation strategy. The decision basis of this strategy is a comprehensive multi-objective heat storage weight factor. ;

[0114] S412, the multi-objective thermal storage weighting factor It is a normalized value ranging from 0 to 1, and its magnitude directly quantifies the comprehensive benefits at the current moment of heating up the heat energy by starting the heat pump unit and then storing it in the high-temperature core heat storage area 21; the calculation formula for this factor is as follows:

[0115] ;

[0116] in: For multi-objective thermal storage weighting factors; As an economic factor, it reflects the electricity cost of operating a heat pump; Thermodynamic potential difference factor reflects the efficiency of heat extraction from a heat source; The energy storage capacity factor reflects the receiving capacity of the high-temperature core thermal storage area 21. , , These are the weighting coefficients for the three sub-factors mentioned above. These coefficients can be pre-calibrated according to the long-term operational goals of the project and satisfy the following conditions: .

[0117] S413, Economic Factors The calculation aims to prioritize the operation of the heat pump during periods of low electricity prices; the calculation formula is as follows:

[0118] ;

[0119] in: It is the highest electricity price charged by the power grid within a complete billing cycle; It is the lowest electricity price charged by the power grid within the same billing cycle;

[0120] S414, thermodynamic potential difference factor The calculation aims to assess the ease and thermodynamic value of extracting heat from power plant cooling water, and the calculation formula is as follows:

[0121] ;

[0122] in: The average temperature of the current high-temperature core thermal storage zone 21 is obtained through calculation. It is the upper limit of the heat source temperature calibrated based on system design or historical operating data; It is the lower limit of the design thermal storage temperature for the high-temperature core thermal storage zone 21;

[0123] S415, Energy Storage Capacity Factor The calculation aims to avoid overheating of the high-temperature core thermal storage zone 21 and to reflect its remaining capacity to continue receiving high-grade thermal energy; the calculation formula is as follows:

[0124] ;

[0125] S416, Dynamic Weighted Heat Flow Scheduling Module 10 calculates in each control cycle... After determining the value, this value is directly used as the proportional coefficient for heat flow distribution. ;Right now:

[0126] ;

[0127] Here Defined as the proportion of the total inflow that should be directed to the heat pump heating loop (i.e., the high-temperature heat storage loop);

[0128] S417, Based on this traffic allocation ratio The dynamic weighted heat flow scheduling module 10 will calculate the specific target flow values ​​for the two thermal storage branches:

[0129] Target flow rate into the high-temperature thermal storage circuit: ;

[0130] Target flow rate into the cryogenic thermal storage circuit: ;

[0131] in: The target flow rate into the high-temperature thermal storage circuit; The target flow rate into the low-temperature thermal storage circuit;

[0132] S418. Subsequently, the dynamic weighted heat flow scheduling module 10 outputs control commands to the actuator network to achieve the aforementioned flow allocation; specifically, it adjusts the opening degree of the corresponding electric regulating valves on the pipeline by outputting continuous control signals. For example, by controlling the combination of the opening degrees of the valve upstream of the heat pump heating loop (logically corresponding to valve V4 in the attached diagram) and the valve upstream of the direct heat storage loop (logically corresponding to valve V6 in the attached diagram), the actual flow rate through the two branches is precisely equal to the calculated target flow rate. and In this way, the present invention achieves continuous, dynamic and optimized coordinated control of the two thermal storage methods.

[0133] Example 2: Refer to Appendix Figure 2 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention.

[0134] S421. When the dynamic weighted heat flow scheduling module 10 determines that the system is in the heat extraction mode during the heating season, it will start the adaptive heat matching heat extraction control method. The method aims to extract heat from the zoned geotechnical energy storage subsystem 20 with the highest efficiency based on the real-time heat load of the end user. Its core is not to directly use a heat source with a higher temperature, but to form a heat source with the lowest available temperature that just meets the high-efficiency operation of the heat pump unit by precisely mixing heat sources from the high-temperature and low-temperature heat storage zones.

[0135] S422. The first step of this control method is to dynamically determine an optimal target evaporation temperature; the central processing unit of the dynamic weighted heat flow scheduling module 10 determines the terminal real-time heat load based on the sensor network. And the water supply temperature required by the user (this temperature determines the condensing temperature of the heat pump). The minimum effective evaporation temperature that meets the current operating conditions is calculated by querying the heat pump performance spectrum function stored internally. The heat pump performance spectrum function exists in the form of a mathematical model or lookup table, describing the relationship between the heat pump's heating capacity and the evaporation and condensation temperatures, and can be expressed as follows: The central processing unit solves equations. To obtain the evaporation temperature that meets the load requirements This is the lowest effective evaporation temperature. .

[0136] S423, after determining the minimum effective evaporation temperature The system will then calculate the target medium temperature required at the inlet of the heat pump evaporator. The target temperature setting takes into account the actual temperature difference required for heat exchange within the evaporator, and its calculation formula is as follows:

[0137] ;

[0138] in: The design heat exchange temperature difference for a heat pump evaporator is a constant preset according to the characteristics of the equipment, such as 3℃-5℃.

[0139] S424, Obtain the target medium temperature Then, the scheduling module 10 will calculate the optimal heat source mixing ratio required to achieve this temperature. This ratio is derived based on the principle of heat balance, and its calculation formula is as follows:

[0140] ;

[0141] in: The optimal heat source mixing ratio is, in physical terms, the proportion of the flow rate from the high-temperature core heat storage zone 21 to the total flow rate.

[0142] S425. Calculate the optimal mixing ratio. Subsequently, the scheduling module 10 does not directly use it as a control command, but instead uses the calculated target temperature. As a setpoint, a closed-loop feedback control program is initiated to precisely control the three-way proportional-integral regulating valve in the adaptive matching heat extraction circuit.

[0143] S426. In a specific embodiment, the closed-loop control program is a proportional-integral-derivative (PID) controller; the PID controller uses... The target setpoint is set using the real-time measurement value of a second temperature sensor located downstream of the three-way proportional-integral control valve as the process variable. Based on the deviation between the target value and the measured value, the controller continuously calculates and outputs a continuous control signal (e.g., a 4-20mA current signal) to the actuator of the three-way proportional-integral control valve using its built-in PID algorithm. The valve actuator adjusts the valve core position according to this signal, thereby changing the mixing ratio of the two fluids from the high-temperature core heat storage zone 21 and the low-temperature coated heat storage zone 22. This closed-loop control process ensures that the temperature of the mixed medium can quickly, stably, and accurately track the dynamically changing target temperature. Ultimately, adaptive matching of heat source quality was achieved.

[0144] Example 3: Refer to Appendix Figure 2 , Figure 2 This is a schematic diagram of the overall system structure according to an embodiment of the present invention.

[0145] S431. The control system of the present invention includes a set of preset timing logic for automatic and smooth transition between different working modes. Taking a typical scenario of switching from the heat storage mode in the non-heating season to the heat extraction mode in the heating season as an example, the dynamic weighted heat flow scheduling module 10 will perform the following series of coordination actions.

[0146] S432. This switching process is triggered by an external command or an internal calendar event. Once the switching command is received, the dynamic weighted heat flow scheduling module 10 first starts the orderly exit procedure of the heat storage circuit. It sends a command to the electric regulating valves (logically corresponding to valves V4 and V6 in the attached diagram) that control the entry into the high-temperature heat storage circuit and the low-temperature heat storage circuit, and linearly reduces the valve opening to zero within a certain time (e.g., 60 seconds) according to the preset ramp function. At the same time, it sends a command to the variable frequency water pump responsible for driving the power plant cooling water circulation, and synchronously and smoothly reduces its operating frequency to zero.

[0147] S433. After the flow on the thermal storage side is completely cut off, the dynamic weighted heat flow scheduling module 10 will perform pipeline isolation and reconfiguration operations. It will issue a command to completely close the main valve V2 used to introduce cooling water into the power plant and the main valve V3 used to return cooling water to the main line of the power plant, so as to achieve physical isolation between this system and the heat source of the power plant. This step includes logical interlocks, that is, the system will confirm that V4 and V6 are fully closed before performing the closing action of V2 and V3 to prevent hydraulic impact.

[0148] S434. After the pipeline isolation is completed, the system enters the pre-start stage of the heat extraction loop; the dynamic weighted heat flow scheduling module 10 issues an instruction to open the supply and return water valves V10 and V11 connected to the heat user side; then, the water pump used to drive the circulating medium on the energy storage well side and the circulating water pump on the user side are started and run at a low initial frequency to establish a stable fluid circulation.

[0149] S435. After confirming that the fluid circulation on the heat extraction side is established and stable, the dynamic weighted heat flow scheduling module 10 will start the heat pump unit; the heat pump unit starts to run according to its own startup procedure and gradually enters a stable working state; at this time, the control of the dynamic weighted heat flow scheduling module 10 will be transferred to the heating season adaptive matching heat extraction algorithm module.

[0150] After the S436 adaptive matching heat extraction algorithm module takes over control, it begins to adjust the user heat load data collected in real time. Calculate target temperature The system activates PID closed-loop control of the three-way proportional-integral regulating valve; at the same time, according to the load demand, the operating frequency of the circulating water pumps on the energy storage well side and the user side is gradually increased until the heat output of the system matches the user demand; at this point, the entire mode switching process from heat storage to heat extraction is smoothly completed, and the system enters a stable heating operation state.

[0151] S437. The process of switching from heat extraction mode back to heat storage mode follows a reverse but equally sequential logic. By first smoothly shutting down the heat pump and user circuit, and then reconstructing the pipeline and smoothly starting the heat storage circuit, the stability and safety of the entire cycle operation are ensured.

[0152] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A system for recovering energy from power plant cooling water using a geotechnical energy storage system coupled with a geotechnical energy storage system, characterized in that, The system comprises: a partitioned rock-soil energy storage subsystem, which comprises a high-temperature core heat storage area and a low-temperature cladding heat storage area surrounding the high-temperature core heat storage area in geographical position; a heat pump unit, which is connected with a circulating system of cooling water of a power plant and the high-temperature core heat storage area, wherein the circulating system of cooling water of the power plant comprises a condenser for cooling turbine exhaust steam and a cooling tower for cooling circulating water, and forms a warm-up cooling water flow carrying residual heat of condensation of the exhaust steam; a sensor network for collecting real-time electricity price and system operation parameters; an actuator network for regulating heat flow path and flow rate; a dynamic weight heat flow scheduling module receiving signals of the sensor network and controlling the actuator network; wherein the dynamic weight heat flow scheduling module is configured to: in a heat storage mode, based on the real-time electricity price and system thermodynamic state parameters collected by the sensor network, calculate a multi-objective heat storage weight factor, determine a heat flow distribution ratio according to the multi-objective heat storage weight factor, and based on the heat flow distribution ratio, control the heat flow introduced from the power plant to be distributed to the low-temperature cladding heat storage area and the high-temperature core heat storage area after being warmed up by the heat pump unit at the same time; in a heat extraction mode, based on a terminal real-time heat load, calculate a target medium temperature, and control the heat flow extracted from the high-temperature core heat storage area and the low-temperature cladding heat storage area to be mixed so that the temperature of the mixed heat flow matches the target medium temperature, and the mixed heat flow is used as a heat source of the heat pump unit.

2. The system for coupling the energy of cooling water of a power plant with the geotechnical energy storage system according to claim 1, characterized in that, The ground heat exchanger in the high-temperature core heat storage area forms a first independent closed circulation pipe network, and the ground heat exchanger in the low-temperature cladding heat storage area forms a second independent closed circulation pipe network which is physically isolated from the first independent closed circulation pipe network; the dynamic weight heat flow scheduling module controls the first independent closed circulation pipe network and the second independent closed circulation pipe network independently through the actuator network.

3. The system for coupling geotechnical energy storage to recover cooling water energy from a power plant of claim 2, wherein, The low-temperature cladding heat storage area is used for directly storing low-grade heat energy from the circulating system of cooling water of the power plant, and by increasing the rock-soil temperature in the low-temperature cladding heat storage area, a heat shield is formed around the high-temperature core heat storage area to reduce the temperature gradient between the high-temperature core heat storage area and the surrounding rock-soil, thereby reducing the dissipation rate of high-grade heat.

4. The system for coupling geotechnical energy storage to recover cooling water energy from a power plant of claim 1, wherein, The value of the heat flow distribution ratio is determined by the value of the multi-objective heat storage weight factor, and the heat flow distribution ratio is the ratio of the flow rate of the heat flow directed to the high-temperature core heat storage area after being warmed up by the heat pump unit to the total introduced flow rate.

5. The system for coupling geotechnical energy storage to recover cooling water energy from a power plant of claim 4, wherein, The multi-objective heat storage weight factor is obtained by weighted summation of an economic factor, a thermodynamic potential difference factor and an energy storage capacity factor; the economic factor is determined based on the relationship between the real-time electricity price and a preset electricity price interval, the thermodynamic potential difference factor is determined based on the relationship between the heat source temperature and the average temperature of the high-temperature core heat storage area, and the energy storage capacity factor is determined based on the relationship between the average temperature of the high-temperature core heat storage area and the upper and lower limits of the design heat storage temperature of the high-temperature core heat storage area.

6. The system for coupling geotechnical energy storage to recover cooling water energy from a power plant of claim 1, wherein, The system further comprises: an adaptive pressure matching heat extraction circuit, which is provided with a three-way proportional integral adjusting valve. The dynamic weight heat flow scheduling module adjusts the mixing ratio of the heat flow extracted from the high-temperature core heat storage area and the low-temperature coated heat storage area by controlling the three-way proportional integral adjusting valve in the heat extraction mode.

7. The system for coupling geotechnical energy storage to recover cooling water energy from a power plant of claim 6, wherein, The dynamic weight heat flow scheduling module controls the three-way proportional integral adjusting valve through a closed-loop feedback control program, and the target medium temperature calculated by the closed-loop feedback control program is a set value, and the real-time measurement value of the second temperature sensor arranged downstream of the three-way proportional integral adjusting valve is a process variable.

8. The system for coupling geotechnical energy storage to recover cooling water energy from a power plant of claim 1, wherein, The sensor network comprises: a first temperature sensor for measuring the temperature of the heat source; a plurality of temperature sensors for measuring the water temperature at the inlet and outlet of each heat storage area; a geothermal temperature sensor arranged inside the partitioned rock-soil energy storage subsystem; a second temperature sensor for measuring the temperature of the mixed medium; a power price signal receiver.

9. The system for coupling geotechnical energy storage to recover cooling water energy from a power plant of claim 1, wherein, The actuator network comprises: a plurality of variable frequency circulating water pumps; a plurality of electric regulating valves and on-off valves for switching fluid paths or adjusting the flow through each branch.

10. A method for coupling the energy of cooling water of a power plant with a geotechnical energy storage system, applied to the system of any one of claims 1-9, characterized in that, The method comprises: In the heat storage mode, continuously collect real-time electricity prices and system thermodynamic state parameters, calculate multi-objective heat storage weight factors, and determine the heat flow distribution ratio according to the multi-objective heat storage weight factors; based on the heat flow distribution ratio, control a part of the temperature rise cooling water flow introduced from the power plant cooling water circulation system to directly enter the low-temperature coated heat storage area for storage, while controlling another part of the introduced heat flow to enter the evaporator of the heat pump unit, and sending the heat flow after being heated by the condenser of the heat pump unit to the high-temperature core heat storage area for storage; In the heat extraction mode, calculate the required target medium temperature according to the real-time heat load of the terminal; based on the target medium temperature and the outlet temperatures of the high-temperature core heat storage area and the low-temperature coated heat storage area, calculate the optimal heat source mixing ratio; and control the heat flow extracted from the two heat storage areas to be mixed according to the optimal heat source mixing ratio, and send the mixed heat flow as a heat source to the heat pump unit to supply heat to the terminal.

Images