Source-load-storage coupled deep geothermal long-time energy storage system and control method

Abstract

The invention discloses a source-load-storage coupled deep geothermal long-time energy storage system and a control method, and belongs to the technical field of geothermal energy storage, the system is composed of a deep heat storage unit, a combined heat and power generation unit, a heat supply plate exchanger, a heat storage plate exchanger, a power grid, a heat supply network and a valve group, and flexible linkage of all the units is achieved through the valve group. According to the control method, on the basis of the source load storage dynamic coordination and ground and underground coupling principle, the real-time electric heating load of the building serves as the requirement standard, a variable-working-condition operation strategy is formulated in the heating season and the non-heating season, and alternate operation of heat storage in the daytime and heat removal at night in the heating season is achieved; and in the non-heating season, the combined heat and power generation unit is controlled to perform pure condensation power generation and deep heat storage closed well operation. The system energy storage efficiency can be improved, the thermal plume diffusion and thermal breakthrough risks are reduced, meanwhile, the system operation cost is reduced, and the initial payback period is shortened.

Description

Technical Field

[0001] This invention belongs to the field of geothermal energy storage and clean energy heating technology, specifically involving the operation and control of deep geothermal long-term energy storage systems and cogeneration coupled building heating systems. Background Technology

[0002] Driven by the dual-carbon strategy, my country's dual demands for clean heating and high-proportion renewable energy consumption continue to escalate, leading to a mismatch between energy supply and demand in time and space for large-scale clean heating systems. On the one hand, wind and solar renewable energy sources are characterized by intermittent fluctuations, and curtailment issues constrain their large-scale grid connection. On the other hand, building heating and cooling loads exhibit significant seasonal and temporal fluctuations, making it difficult for traditional combined heat and power (CHP) units, operating on a heat-driven power generation model, to simultaneously ensure power supply reliability and heating flexibility.

[0003] Deep geothermal long-term energy storage technology, with its natural advantages of high reservoir temperature, large reserves, and stable output, is more suitable for large-scale, cross-seasonal energy buffering needs compared to conventional hydrothermal storage technology, becoming an important technical solution for solving the supply-demand mismatch in clean heating systems. Currently, scholars both domestically and internationally have conducted extensive numerical simulation studies on deep geothermal energy storage systems. Early research focused on single-physics simulations of underground thermal reservoirs, while subsequent studies have gradually attempted to correlate surface systems with underground thermal reservoirs. However, existing technologies still have significant limitations.

[0004] Most technologies employ a decoupled operation mode between the building load of the surface heat source and the underground thermal storage, neglecting the dynamic feedback of heat source fluctuations and cogeneration unit variations on the evolution of the underground thermal storage temperature field, thus failing to accurately reflect the dynamic characteristics of the system operation. Existing technologies simplify the thermal storage source temperature and heat extraction / reinjection temperature to constant values, failing to consider the thermal storage temperature fluctuations caused by adjustments in the cogeneration unit's extraction rate, as well as the changes in heat extraction / reinjection temperature due to dynamic building loads, resulting in poor matching with actual load demands. Existing technologies generally adopt a fixed mode of continuous heat extraction during the heating season and continuous heat storage during the non-heating season, leading to long storage periods, severe heat attenuation, excessive heat plume diffusion, and even the risk of thermal breakthrough. Furthermore, due to unreasonable heat storage capacity and significant heat loss, existing technologies result in high system operating costs, low energy storage efficiency, and long initial investment payback periods, hindering the large-scale application of the technology. Existing deep geothermal energy storage systems and control methods cannot achieve full-chain dynamic coordination between heat source load and thermal storage, making it difficult to adapt to the variable operating conditions required for large-scale clean heating. Summary of the Invention

[0005] The purpose of this invention is to provide a source-load-storage coupled deep geothermal long-term energy storage system and control method to solve the problems of low energy storage efficiency and excessive heat plume diffusion range caused by the decoupling of the surface and underground and the simplification of the operation mode in existing deep geothermal energy storage systems, while alleviating the spatiotemporal mismatch of energy supply and demand in clean heating systems.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a source-load-storage coupled deep geothermal long-term energy storage system, comprising:

[0008] The system comprises a deep geothermal storage unit, a combined heat and power (CHP) unit, a heating plate heat exchanger, a thermal storage plate heat exchanger, a power grid unit, a heating network unit, and a valve assembly. The CHP unit outputs electrical and thermal energy and is bidirectionally electrically connected to the power grid unit. The steam outlet and return water inlet of the CHP unit are connected to the primary side of the heating plate heat exchanger and the primary side of the thermal storage plate heat exchanger, respectively, via the valve assembly. The deep geothermal storage unit stores and releases geothermal energy and is connected to the secondary side of the thermal storage plate heat exchanger via the valve assembly. The heating network unit includes a supply water network and a return water network. The return water network is connected to the secondary side of the heating plate heat exchanger and the secondary side inlet of the thermal storage plate heat exchanger, respectively, via the valve assembly. The supply water network is connected to the secondary side of the heating plate heat exchanger and the secondary side outlet of the thermal storage plate heat exchanger, respectively, via the valve assembly. The valve assembly controls the on / off state and flow direction of each pipeline, with each valve installed on its corresponding connecting pipeline.

[0009] In one possible implementation, the deep thermal storage unit includes:

[0010] The system includes a cold well, a hot well, a cold well pump, and a hot well pump. The cold well pump is installed inside the cold well, and the hot well pump is installed inside the hot well. The outlet of the cold well pump is connected to the secondary inlet pipe of the thermal storage plate heat exchanger via a twelfth valve, and the secondary outlet of the thermal storage plate heat exchanger is connected to the inlet pipe of the hot well via an eleventh valve. The outlet of the hot well pump is connected to the secondary inlet pipe of the thermal storage plate heat exchanger via an eleventh valve, and the secondary outlet of the thermal storage plate heat exchanger is connected to the inlet pipe of the cold well via a twelfth valve.

[0011] In one possible implementation, the valve assembly includes:

[0012] First valve, second valve, third valve, fourth valve, fifth valve, sixth valve, seventh valve, eighth valve, ninth valve, tenth valve, eleventh valve, twelfth valve, thirteenth valve, and fourteenth valve; the first valve is connected in series to the steam outlet main pipe of the cogeneration unit, and the second valve is connected in series to the return water inlet main pipe of the cogeneration unit; the third valve is connected in series to the pipe between the first valve and the primary heat exchanger inlet of the heating plate, and the fourth valve is connected in series to the pipe between the primary heat exchanger outlet of the heating plate and the second valve; the seventh valve is connected in series to the pipe between the first valve and the primary heat exchanger inlet of the thermal storage plate, and the eighth valve is connected in series to the... The pipeline is connected between the primary outlet of the heat exchanger and the second valve; the ninth valve is connected in series in the pipeline between the primary outlet of the heat exchanger and the primary inlet of the heat exchanger; the tenth valve is connected in series in the pipeline between the primary outlet of the heat exchanger and the outlet end of the seventh valve; the fifth valve is connected in series in the pipeline between the secondary outlet of the heat exchanger and the water supply network; the sixth valve is connected in series in the pipeline between the return water network and the secondary inlet of the heat exchanger; the thirteenth valve is connected in series in the pipeline between the return water network and the secondary inlet of the heat exchanger; and the fourteenth valve is connected in series in the pipeline between the secondary outlet of the heat exchanger and the water supply network.

[0013] In one possible implementation, the cogeneration unit is a coal-fired cogeneration unit, the cogeneration unit adopts a condensing-heating medium-pressure cylinder exhaust steam supply mode, and the extraction steam outlet of the cogeneration unit is connected to the inlet pipeline of the first valve.

[0014] Secondly, the present invention provides a control method for a source-load-storage coupled deep geothermal long-term energy storage system, applicable to any of the systems described above, comprising the following steps:

[0015] The collected building environment parameters and system operating parameters are calculated and processed to obtain real-time building electric heating load data;

[0016] Based on the real-time building electric heating load data, the operating periods for the heating season and non-heating season are divided, and corresponding variable operating condition strategies are generated for each period.

[0017] Based on the aforementioned variable operating condition strategy, the cogeneration unit is adjusted to high load variable operating condition during the daytime heat storage period in the heating season, and heat storage control operation is performed on the deep heat storage.

[0018] Based on the aforementioned variable operating condition strategy, the cogeneration unit is adjusted to low load variable operating condition during the nighttime heat extraction period in the heating season, and heat extraction and heating control operations are performed on the deep thermal storage.

[0019] According to the aforementioned variable operating condition strategy, the cogeneration unit will be switched to pure condensing operation mode during the non-heating season, and well closure control operation will be performed on the deep thermal reservoir.

[0020] By using a multi-module dynamic iterative coupling method, the operating parameters of system equipment and the opening degree of valve groups are adjusted in real time to achieve source-load-storage coordinated control.

[0021] In one possible implementation, the calculation and processing of the collected building environment parameters and system operating parameters to obtain the real-time building electrical and heating load data includes: constructing a building dynamic load model using the lumped parameter method of 5 thermal resistance and 1 thermal capacity; discretizing time using the explicit Euler method; solving the building dynamic load model using the fourth-order Runge-Kutta method; and outputting the real-time building heat load and electrical load data.

[0022] In one possible implementation, the high-load variable operating condition adjustment of the cogeneration unit during the daytime heat storage period in the heating season, and the heat storage control operation of the deep heat storage, include: starting the cold well pump and shutting down the hot well pump and the heat exchanger; opening the corresponding valve group to connect the heat storage channel; constructing a variable operating condition mathematical model describing the coupling relationship between electricity, heat and fuel; using a sequential quadratic programming algorithm to solve the grid balance constraints; dynamically adjusting the pumping rate and load rate of the cogeneration unit; and completing the heat exchange between the cogeneration unit and the deep heat storage through the heat storage heat exchanger to realize the heat storage operation of the deep heat storage.

[0023] In one possible implementation, the low-load variable operating condition adjustment of the cogeneration unit during the nighttime heat extraction period in the heating season, and the heat extraction and supply operation of the deep thermal storage, include: starting the hot well pump and the heat exchanger and shutting down the cold well pump; opening the corresponding valve group to connect the heat extraction and supply flow channel; discretizing the reservoir space of the coupled model using the finite volume method, and completing the time dimension discretization by combining the explicit Euler method; solving the discretized coupled model hourly, dynamically adjusting the heat extraction power of the deep thermal storage, using the heat exchanger to complete the heat exchange between the deep thermal storage and the return water of the heating network, and then delivering the return water of the heating network to the building end after secondary heating through the heat exchanger, thereby realizing the heat extraction and supply operation of the deep thermal storage.

[0024] In one possible implementation, switching the cogeneration unit to pure condensing operation mode during the non-heating season and performing well-closure control operations on the deep thermal reservoir includes adjusting the cogeneration unit to pure condensing operation mode for full-load power generation, shutting down the cold well pump, hot well pump, heating plate heat exchanger and storage plate heat exchanger, and closing all valves in the valve group to cut off the water and heat flow channels between the surface and the underground, so as to keep the deep thermal reservoir temperature field stable by keeping the well closed throughout the process.

[0025] In one possible implementation, the method of using a multi-module dynamic iterative coupling method to adjust the system equipment operating parameters and valve group opening in real time includes solving the combined heat and power unit variable operating condition model, the building dynamic load model, and the deep thermal storage infiltration heat transfer coupling model, respectively, feeding back the solution results of each model to iterate until the temperature, flow rate, and power errors of adjacent iteration steps meet the preset threshold, and automatically adjusting the equipment operating parameters and valve group opening based on the iteration results and monitoring data.

[0026] Compared with the prior art, the advantages of this invention are as follows:

[0027] This invention constructs a source-load-storage coupled deep geothermal long-term energy storage system. Through the linkage architecture of deep geothermal storage, cogeneration units, heating plate heat exchangers, storage plate heat exchangers, heat network, and valve groups, it achieves full-chain dynamic linkage between cogeneration units, building dynamic loads, and deep geothermal storage, breaking the limitation of decoupled operation of ground heat source, building load, and underground geothermal storage in existing technologies. Existing technologies ignore the dynamic feedback of heat source fluctuations and unit operating conditions on the evolution of underground geothermal storage temperature field, and cannot truly reflect the dynamic characteristics of system operation. However, this system achieves flexible switching between geothermal storage, heating, and pure condensing power generation modes through the opening and closing combination of valve groups. This allows changes in unit operating status to be transmitted to deep geothermal storage in real time, and the storage and extraction status of geothermal storage can also be synchronously fed back to the operation adjustment of the ground system, realizing the coupling and linkage between the ground and underground, and truly restoring the dynamic operating characteristics of the entire system process.

[0028] This invention, based on the principle of dynamic synergy between heat source, load, and storage, proposes a time-segmented variable operating condition strategy. Using the building's real-time electric heating load as the demand benchmark, it employs an alternating operation mode during the heating season, storing heat during the day and extracting heat at night. This differs from the fixed mode commonly used in existing technologies, which involves continuous heat extraction during the heating season and continuous heat storage during the non-heating season. The fixed operation mode of existing technologies has a long heat storage cycle, easily leading to severe heat attenuation and causing excessive heat plume diffusion or even thermal breakthrough risks. The alternating operation mode of this invention significantly shortens the single heat storage cycle, reduces heat attenuation during the storage process, and dynamically adjusts the unit's air extraction rate through a sequential quadratic programming algorithm and dynamically adjusts the heat extraction power through a fourth-order Runge-Kutta method. This ensures that the heat storage temperature and the heat extraction and reinjection temperature can adapt to real-time changes in load fluctuations, solving the problem of existing technologies simplifying the heat storage and extraction temperatures to constant values, resulting in poor matching with actual load demand. This achieves adaptive matching between the building's dynamic load and the heat source and heat storage system.

[0029] The system and control method of this invention can effectively improve the operating efficiency of deep geothermal long-term energy storage, suppress heat plume diffusion, and reduce the risk of thermal breakthrough. Compared with conventional operation modes, the long-term energy storage efficiency of this scheme can be improved by approximately 26.4%, the heat plume radius can be reduced by 65.8% to 84.8%, and the system heat storage capacity can be reduced by 50.4% to 64.5%. Existing technologies are prone to unnecessary heat storage operations and heat loss due to unreasonable heat storage capacity settings. This scheme, however, uses a multi-module dynamic iterative coupling method to solve the deep geothermal storage seepage heat coupling equation in real time, update the geothermal storage temperature field, and monitor the heat plume diffusion range. It can adjust equipment operating parameters and valve openings in real time according to the geothermal storage operating status, achieving reasonable optimization of heat storage capacity while meeting heating demand, reducing unnecessary heat loss, and ensuring the long-term stability of deep geothermal storage, thus avoiding the occurrence of thermal breakthrough problems.

[0030] The system and control method of this invention can effectively improve the economics and resource utilization efficiency of deep geothermal long-term energy storage technology. Compared with conventional operation modes, the system operating cost of this solution can be reduced by 50.4% to 64.5%, the initial investment payback period can be shortened by 24.3% to 43.5%, and the operating benefits can be increased by 32.1% to 77.1%. Simultaneously, the system adopts a water-free operation mode where neither heat storage nor heat extraction consumes water. During heat storage, cold well water is heated and injected into the hot well; during heat extraction, the hot well water is released and reinjected into the cold well, achieving full recycling of geothermal fluids and improving water resource utilization efficiency. Furthermore, the combined heat and power (CHP) unit prioritizes the electricity generated to meet building loads, with surplus electricity sold to the grid. This enhances the unit's peak-shaving capacity while also promoting the consumption of renewable energy, adapting to the construction and operation needs of large-scale clean heating in cold regions. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of a source-load-storage coupled deep geothermal long-term energy storage system in an embodiment of the present invention;

[0033] Figure 2 This is a control flowchart of a source-load-storage coupled deep geothermal long-term energy storage system according to an embodiment of the present invention;

[0034] Figure 3 This is one of the comparison charts showing the simulation results of the deep geothermal long-term energy storage system according to an embodiment of the present invention.

[0035] Figure 4This is the second comparison chart of the simulation results of the deep geothermal long-term energy storage system according to an embodiment of the present invention.

[0036] In the picture: (attached) Figure 1 The components corresponding to each number are as follows: 1. Deep thermal storage; 11. Cold well; 12. Hot well; 13. Cold well pump; 14. Hot well pump; 2. Cogeneration unit; 3. Heating heat exchanger; 4. Thermal storage heat exchanger; 5. Power grid; 6. Heating network; 61. Water supply network; 62. Return water network; v1-v14 correspond to valves one through fourteen. Detailed Implementation

[0037] The technical solutions of 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 this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0038] Example:

[0039] It should be noted that the terms "comprising" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0040] See Figure 1 This embodiment of a source-load-storage coupled deep geothermal long-term energy storage system includes:

[0041] The system comprises a deep geothermal storage unit, a combined heat and power (CHP) unit, a heating plate heat exchanger, a thermal storage plate heat exchanger, a power grid unit, a heating network unit, and a valve assembly. The CHP unit outputs electrical and thermal energy and is bidirectionally electrically connected to the power grid unit. The steam outlet and return water inlet of the CHP unit are connected to the primary side of the heating plate heat exchanger and the primary side of the thermal storage plate heat exchanger, respectively, via the valve assembly. The deep geothermal storage unit stores and releases geothermal energy and is connected to the secondary side of the thermal storage plate heat exchanger via the valve assembly. The heating network unit includes a supply water network and a return water network. The return water network is connected to the secondary side of the heating plate heat exchanger and the secondary side inlet of the thermal storage plate heat exchanger, respectively, via the valve assembly. The supply water network is connected to the secondary side of the heating plate heat exchanger and the secondary side outlet of the thermal storage plate heat exchanger, respectively, via the valve assembly. The valve assembly controls the on / off state and flow direction of each pipeline, with each valve installed on its corresponding connecting pipeline.

[0042] Specifically, the deep geothermal reservoir unit can be a sandstone-type geothermal reservoir structure buried at a depth of 4000m; the cogeneration unit can be a coal-fired cogeneration unit with a rated power generation of 247MW and a rated heating capacity of 180MW; the heat exchange plate heat exchanger can be a plate heat exchanger with a heat exchange capacity of 50MW; the heat storage plate heat exchanger can be a plate heat exchanger with a heat exchange capacity of 40MW; the power grid unit can be a regional public power transmission and distribution network; the heating network unit can be a centralized heating network connecting the heat source and the building heating terminal; the valve group can be a pipeline on / off control assembly consisting of 14 electrically operated valves; the water supply network can be a pipeline that delivers high-temperature heating water to the building; and the return water network can be a pipeline that recovers low-temperature return water from the building.

[0043] In one possible implementation, the deep thermal storage unit includes:

[0044] The system includes a cold well, a hot well, a cold well pump, and a hot well pump. The cold well pump is installed inside the cold well, and the hot well pump is installed inside the hot well. The outlet of the cold well pump is connected to the secondary inlet pipe of the thermal storage plate heat exchanger via a twelfth valve, and the secondary outlet of the thermal storage plate heat exchanger is connected to the inlet pipe of the hot well via an eleventh valve. The outlet of the hot well pump is connected to the secondary inlet pipe of the thermal storage plate heat exchanger via an eleventh valve, and the secondary outlet of the thermal storage plate heat exchanger is connected to the inlet pipe of the cold well via a twelfth valve.

[0045] Specifically, the cold wells can be four geothermal reinjection wells with a depth of 4000m; the hot wells can be four geothermal production wells with a depth of 4000m; the cold well pumps can be deep well submersible pumps that reach a set rated flow rate; the hot well pumps can be deep well submersible pumps that reach a set rated flow rate; and the eleventh and twelfth valves can be electrically operated valves.

[0046] In one possible implementation, the valve assembly includes:

[0047] First valve, second valve, third valve, fourth valve, fifth valve, sixth valve, seventh valve, eighth valve, ninth valve, tenth valve, eleventh valve, twelfth valve, thirteenth valve, and fourteenth valve; the first valve is connected in series to the steam outlet main pipe of the cogeneration unit, and the second valve is connected in series to the return water inlet main pipe of the cogeneration unit; the third valve is connected in series to the pipe between the first valve and the primary heat exchanger inlet of the heating plate, and the fourth valve is connected in series to the pipe between the primary heat exchanger outlet of the heating plate and the second valve; the seventh valve is connected in series to the pipe between the first valve and the primary heat exchanger inlet of the thermal storage plate, and the eighth valve is connected in series to the... The pipeline is connected between the primary outlet of the heat exchanger and the second valve; the ninth valve is connected in series in the pipeline between the primary outlet of the heat exchanger and the primary inlet of the heat exchanger; the tenth valve is connected in series in the pipeline between the primary outlet of the heat exchanger and the outlet end of the seventh valve; the fifth valve is connected in series in the pipeline between the secondary outlet of the heat exchanger and the water supply network; the sixth valve is connected in series in the pipeline between the return water network and the secondary inlet of the heat exchanger; the thirteenth valve is connected in series in the pipeline between the return water network and the secondary inlet of the heat exchanger; and the fourteenth valve is connected in series in the pipeline between the secondary outlet of the heat exchanger and the water supply network.

[0048] Specifically, the first to fourteenth valves can all be electrically operated valves; the steam outlet main pipeline can be the main output pipeline for the exhaust steam from the intermediate pressure cylinder of the cogeneration unit; and the return water inlet main pipeline can be the main input pipeline for the return of condensate after heat exchange to the cogeneration unit.

[0049] In one possible implementation, the cogeneration unit is a coal-fired cogeneration unit, the cogeneration unit adopts a condensing-heating medium-pressure cylinder exhaust steam supply mode, and the extraction steam outlet of the cogeneration unit is connected to the inlet pipeline of the first valve.

[0050] Specifically, a coal-fired cogeneration unit can be a steam turbine generator unit equipped with a supercritical boiler and featuring extraction condensing steam; the condensing-heating intermediate-pressure cylinder exhaust steam supply mode can be an operating mode in which the extraction rate is continuously adjusted from 0 to 0.8 by adjusting the steam intake of the low-pressure cylinder; the extraction steam outlet can be the exhaust port of the intermediate-pressure cylinder of the steam turbine.

[0051] This embodiment also provides a control method for a source-load-storage coupled deep geothermal long-term energy storage system, applicable to any of the systems described above, including the following steps:

[0052] Step 101: Calculate and process the collected building environment parameters and system operating parameters to obtain real-time building electric heating load data.

[0053] Specifically, building environment parameters can be outdoor temperature, solar radiation intensity, and wind speed; system operating parameters can be combined heat and power unit power generation, extraction rate, deep thermal storage injection and extraction flow rate, and heating network supply and return water temperature.

[0054] The process of calculating and processing the collected building environment parameters and system operating parameters to obtain real-time building electrical and heating load data includes: constructing a building dynamic load model using the lumped parameter method of 5 thermal resistance and 1 thermal capacity; discretizing time using the explicit Euler method; solving the building dynamic load model using the fourth-order Runge-Kutta method; and outputting real-time building heat load and electrical load data.

[0055] Specifically, the 5 thermal resistance 1 heat capacity lumped parameter method can be a lumped parameter calculation method that simplifies the thermal process of a building envelope into 5 thermal resistances and 1 heat capacity; the building dynamic load model can be a differential equation model that describes the changes in building thermal process and electrical and heating load; the explicit Euler method can be a numerical calculation method that discretizes the time dimension; time discretization can be a method that divides continuous time into discrete time periods with a step size of 1 hour; the fourth-order Runge-Kutta method can be a high-precision numerical iterative method for solving differential equations; the real-time building heat load can be the hourly heating power demand of the building; and the real-time building electrical load can be the hourly electricity demand of the building.

[0056] For example, a building dynamic load model is constructed using the 5 thermal resistance 1 heat capacity lumped parameter method:

[0057] Time is discretized using the explicit Euler method:

[0058] In the above formula: The equivalent heat capacity of the building is expressed in J / ℃. , Let t be the indoor and outdoor temperatures, in °C. , Let W be the total heat gain and total heat loss of the building at time t; , Let W be the building's heat load and cooling load at time t; , Let W be the heat gain from solar radiation and the heat gain from indoor disturbances at time t. Let be the solar radiation intensity at time t, in W / m². , Areas of windows and exterior walls / roofs, both in m². , The solar radiation transmittance of windows and the solar radiation absorption heat gain coefficient of building envelope are both dimensionless. Let be the shading coefficient at time t, which is dimensionless; For the building's overall equivalent thermal resistance, ~ The external convection thermal resistance, the main body thermal conductivity thermal resistance, the internal convection thermal resistance, the window overall thermal resistance, and the equivalent thermal resistance of infiltration air are all expressed in °C / W. , Set the temperature for heating and cooling, in °C; , , , For time t, the heating load power, cooling load power, total building electrical load power, and personnel / equipment / lighting / rest load power are all in W; , The coefficients of performance for heating and cooling are dimensionless. For the time step, this invention uses 3600s (1h).

[0059] The collected environmental parameters, such as outdoor temperature and solar radiation intensity, are substituted into the building dynamic load model. The model is then solved hourly using the fourth-order Runge-Kutta method to output the real-time building heat load. With electrical load data .

[0060] Step 102: Based on the real-time building electric heating load data, divide the operating periods into heating season and non-heating season, and generate variable operating conditions strategies for the corresponding time periods.

[0061] Specifically, the real-time building electric heating load data can be the building's hourly heat load and hourly electric load; the heating season can be the cold period from November 15th of each year to March 15th of the following year; the non-heating season can be the warm period from March 16th of each year to November 14th.

[0062] Step 103: Based on the variable operating condition strategy, adjust the cogeneration unit to high load variable operating condition during the daytime heat storage period in the heating season, and perform heat storage control operation on the deep heat storage.

[0063] Specifically, the variable operating condition strategy can be to adapt the unit operating parameters, valve opening and closing combinations, and pump start-up and shutdown rules to different time periods of load. The daytime heat storage period can be from 7:00 to 19:00 every day.

[0064] The high-load variable operating condition adjustment of the cogeneration unit during the daytime heat storage period in the heating season, and the heat storage control operation of the deep heat storage, include: starting the cold well pump and shutting down the hot well pump and the heat exchanger; opening the corresponding valve group to connect the heat storage channel; constructing a variable operating condition mathematical model describing the coupling relationship between electricity, heat and fuel; using a sequential quadratic programming algorithm to solve the grid balance constraints; dynamically adjusting the pumping rate and load rate of the cogeneration unit; and completing the heat exchange between the cogeneration unit and the deep heat storage through the heat storage heat exchanger to realize the heat storage operation of the deep heat storage.

[0065] Specifically, the cold well pump can be a deep well submersible pump installed inside a cold well; the hot well pump can be a deep well submersible pump installed inside a hot well; the heat exchanger plate can be a plate heat exchanger connecting the cogeneration unit and the heating network; the heat storage channel can be a connecting pipeline between the cogeneration unit, the heat storage plate heat exchanger, and the deep heat storage; the sequential quadratic programming algorithm can be a numerical algorithm for solving constrained nonlinear optimization problems; the grid balance constraint can be the power balance constraint between the power generation of the cogeneration unit and the building's electrical load and the power sold by the grid; the extraction rate can be the proportion of steam from the intermediate-pressure cylinder exhaust of the cogeneration unit used for heating, with an adjustment range of 0 to 0.8; the load factor can be the ratio of the actual operating power of the cogeneration unit to its rated power; and the heat storage plate heat exchanger can be a plate heat exchanger connecting the cogeneration unit and the deep heat storage.

[0066] For example, for a cogeneration unit using a condensing heating medium-pressure cylinder exhaust steam supply mode, a variable operating condition mathematical model describing the coupling relationship between electricity, heat and fuel is constructed.

[0067] In the formula: Let be the extraction rate of the CHP unit at time t, which is dimensionless. Let t be the power generation capacity of the CHP unit, in kW; , ~ These are the fitting coefficients for the measured data; Let t be the cylinder cutting ratio. The maximum cylinder cutting ratio is dimensionless. Rated main steam flow rate, t / h; Minimum cooling flow rate for the low-pressure cylinder, t / h; Let be the load rate of the CHP unit at time t, which is dimensionless. , , Let t be the heating power of the medium-pressure cylinder extraction, the heating power of the low-pressure cylinder cutting, and the total heating power of CHP, all in kW. The specific enthalpy of the vacuum pump. For the specific enthalpy of the heating return water, For exhaust enthalpy, The main steam specific enthalpy is , all in kJ / kg; Let be the fuel input power at time t, in kW; For boiler efficiency, Let be the overall efficiency of the CHP unit at time t, which is dimensionless.

[0068] Combining the power grid balance constraints, a sequential quadratic programming algorithm is used to solve the mathematical model of the variable operating conditions, obtaining parameters such as the extraction rate, load rate, cylinder cut-off ratio, power generation and heating power of the cogeneration unit under the corresponding operating conditions; based on the solved parameters, the steam intake of the low-pressure cylinder of the cogeneration unit is adjusted to realize the variable operating condition adjustment of the unit's extraction rate and load rate.

[0069] Step 104: Based on the variable operating condition strategy, adjust the cogeneration unit to low load during the nighttime heat extraction period in the heating season, and perform heat extraction and heating control operations on the deep thermal storage.

[0070] Specifically, the nighttime heating period can be from 19:00 to 7:00 the next day.

[0071] The process of adjusting the cogeneration unit to low-load variable operating conditions during the nighttime heating period in the heating season and performing heat extraction and supply operations on the deep thermal storage includes: starting the hot well pump and the heat exchanger and shutting down the cold well pump; opening the corresponding valve group to connect the heat extraction and supply channels; constructing a deep thermal storage seepage heat transfer coupling model based on Darcy's law and the law of conservation of energy; discretizing the reservoir space of the coupling model using the finite volume method and completing the time dimension discretization using the explicit Euler method; solving the discretized coupling model hourly to dynamically adjust the heat extraction power of the deep thermal storage; using the heat exchanger to complete the heat exchange between the deep thermal storage and the return water of the heating network; and delivering the return water of the heating network to the building end after secondary heating through the heat exchanger, thereby realizing the heat extraction and supply operation of the deep thermal storage.

[0072] Specifically, the heat extraction and supply flow path can be the connecting pipeline between the deep heat storage, the heat storage heat exchanger, the heat supply heat exchanger and the heating network; the heat extraction power can be the heat energy released by the deep heat storage per unit time; the heating network return water can be the low-temperature heating water returning from the building end; the secondary heating can be the heating network return water being initially heated by the heat storage heat exchanger, and then further heated by the heat supply heat exchanger to the set supply water temperature.

[0073] For example, based on Darcy's law and the law of conservation of energy, a seepage heat transfer coupling model for deep thermal reservoirs is constructed:

[0074] Deep geothermal reservoir boundary and initial conditions:

[0075] In the above formula: Reservoir porosity, dimensionless; The density of the geothermal fluid is kg / m³. Darcy's velocity, in m / s; For fluid source / sink, kg / (m³·s); Let mD be the reservoir permeability. The viscosity of the geothermal fluid is Pa·s; The reservoir pressure is expressed in Pa. The acceleration due to gravity is expressed in m / s². Let m be the vertical coordinate of the reservoir. The equivalent heat capacity of the reservoir is kJ / (m³·℃). Let t be the reservoir space coordinate temperature, in °C; is the specific heat of geothermal fluid, kJ / (kg·℃); The equivalent thermal conductivity of the reservoir is W / (m·℃). The heat generated during injection is expressed in J / (m³·s). Let t be the heat storage of the reservoir, in kJ; , Let τ be the thermal storage power and thermal extraction power, both in kW; Let t be the reservoir heat loss, in kJ; Let be the energy storage efficiency at time t, which is dimensionless; Let be the radius of the thermal plume at time t, in meters. The coordinates of the grid center, in meters, represent the temperature rise not being lower than the set value. , Here are the center coordinates of the hot and cold well locations, in meters (m). The original formation temperature is given in °C. The geothermal gradient is expressed in °C / km. Let t be the hot well injection temperature at time t, in °C; Let t be the cold well reinjection temperature at time t, in °C.

[0076] The reservoir space of the coupled model is discretized using the finite volume method, and the time dimension is discretized using the explicit Euler method. The discretized coupled model is solved hourly to obtain the thermal power, heat extraction power, energy storage efficiency, reservoir temperature field and thermal plume radius parameters of the deep thermal reservoir.

[0077] Based on the obtained thermal plume radius parameters, the thermal plume diffusion range of the deep thermal reservoir is monitored in real time. Combined with the thermal storage power and heat extraction power parameters, the heating supply and heat extraction control of the deep thermal reservoir is completed.

[0078] Step 105: Based on the variable operating condition strategy, switch the cogeneration unit to pure condensing operation mode during the non-heating season and perform well closure control operation on the deep thermal reservoir.

[0079] The aforementioned switching of the cogeneration unit to pure condensing operation mode during the non-heating season and performing well-closure control operations on the deep thermal reservoir includes adjusting the cogeneration unit to pure condensing operation mode for full-load power generation, shutting down the cold well pump, hot well pump, heating plate heat exchanger and storage plate heat exchanger, and closing all valves in the valve group to cut off the water and heat flow channels between the surface and underground, so as to keep the deep thermal reservoir temperature field stable by keeping the well closed throughout the process.

[0080] Step 106: Using a multi-module dynamic iterative coupling method, the operating parameters of the system equipment and the valve group opening are adjusted in real time to complete the source-load-storage coordinated control.

[0081] The method of using a multi-module dynamic iterative coupling method to adjust the operating parameters of system equipment and valve group opening in real time includes solving the variable operating condition model of the cogeneration unit, the dynamic load model of the building, and the deep thermal storage infiltration heat transfer coupling model, respectively, feeding back the solution results of each model to iterate until the temperature, flow rate, and power errors of adjacent iteration steps meet the preset thresholds, and automatically adjusting the operating parameters of equipment and valve group opening based on the iteration results and monitoring data.

[0082] For example, the system is divided into an electric side module, a load module, and a thermal storage and heating module, and the model of each module is solved. The solution results of the electric side module, the load module, and the thermal storage and heating module are fed back to each other to complete a single iteration calculation. The temperature, flow rate, and power errors of adjacent iteration steps are checked to see if they meet the preset thresholds. If they do not meet the thresholds, the module solution and iteration feedback steps are repeated until the error meets the preset thresholds, thus completing the coupled solution of the system. Based on the coupled solution results, the operating parameters of the system equipment and the valve group opening are automatically adjusted.

[0083] The electrical balance constraint corresponding to the linkage relationship is:

[0084] In the formula: , Let t be the power purchased from the grid by the system and the power sold to the grid by the CHP unit, both in kW. Let t be the thermal power of the deep thermal storage at time t, in kW.

[0085] First, the grid balance constraints are solved using a sequential quadratic programming algorithm to complete the calculation of the cogeneration unit's variable operating condition model on the power side module, and then the cogeneration unit is output. and Then, the building dynamic load model is solved using the fourth-order Runge-Kutta method to complete the load module calculation and output the results. and Subsequently, the heat transfer equations of the deep thermal storage were solved using the finite volume method to complete the calculation of the thermal storage and heating module, and the output was generated. and Finally, the calculation results of each module are fed back to each other, and the calculation process of the aforementioned modules is repeated until the temperature, flow rate, and power errors of adjacent iteration steps are respectively less than [a certain value]. , , This completes the single-cycle system coupling solution.

[0086] See Figure 2 The system control method of this invention is divided into three operating modes: daytime heat storage mode during the heating season, nighttime heating mode during the heating season, and pure condensation power generation mode during the non-heating season. Each mode is based on the aforementioned mathematical model to achieve quantitative control. The daytime heat storage mode during the heating season operates from 7:00 to 19:00, and the specific operation process of this mode is as follows: First, the outdoor temperature is collected. Solar radiation intensity Environmental parameters are substituted into the building dynamic load model to solve for the building's real-time heat load. Real-time electrical load of buildings The obtained load data is used as the reference for system control. Then, the obtained real-time building electrical load is... Substituting the variable operating condition model and the electrical balance constraint model of the cogeneration unit, the extraction rate is solved using a sequential quadratic programming algorithm. Load factor Total heating power The high-load operating parameters of the unit are determined. Then, the cold well pump 13 is started, valves v1, v2, v7, v8, v9, v10, v11, and v12 are opened, and valves v3, v4, v5, v6, v13, and v14 are closed, cutting off the heating flow channel of the heating network 6 and connecting the heat storage flow channels of the cogeneration unit 2, the heat exchanger plate 4, and the deep heat storage 1. The relationship between the heating power supplied by the intermediate-pressure cylinder of the cogeneration unit and the heat storage power of the deep heat storage is then established. The thermal power of the deep thermal reservoir is determined, and this power value is substituted into the deep thermal reservoir seepage heat transfer coupling model to solve for the flow rate of the cold well pump 13 and the injection temperature of the hot well. This allows for the adjustment of the thermal storage flow rate. Simultaneously, the thermal plume radius is calculated hourly using a deep thermal storage model. Ensure it is within a safe threshold, if the thermal plume radius If the threshold is exceeded, the extraction rate will be reduced by using a combined heat and power unit. Reduce thermal storage power. Perform a multi-module dynamic iterative coupled solution every 1 hour to verify whether the temperature, flow rate, and power errors meet the threshold. If not, adjust the parameters of the cogeneration unit or the pump flow rate.

[0087] The nighttime heating mode operates from 7:00 PM to 7:00 AM the following day during the heating season. The specific operation process of this mode is as follows: First, environmental parameters are collected and substituted into the building dynamic load model to solve for the peak nighttime heat load. Then, the nighttime building's real-time electrical load will be recorded. Substitute the variable operating condition model of the cogeneration unit into the equation to solve for the total heating power of the cogeneration unit under low load. The reduced power generation and heating capacity of the generating units are then determined. This is subsequently determined by thermal balance constraints. Solve for the required additional heat extraction power of deep thermal storage. Then start the hot well pump 14 and the heating plate heat exchanger 3, open valves v9, v10, v11, v12, v13, and v14, and close valves v1, v2, v3, v4, v5, v6, v7, and v8 to connect the heating channels of deep thermal storage 1, thermal storage plate heat exchanger 4, and heating network 6. This will allow the deep thermal storage to extract heat. Substituting the data into the deep thermal reservoir seepage heat coupling model, we can solve for the flow rate of the hot well pump 14 and the cold well reinjection temperature. This allows for the adjustment of the heat extraction flow rate. Simultaneously, the energy storage efficiency is calculated hourly. And heating temperature, ensuring that the heating temperature is stable at the building's set heating temperature. Simultaneously monitor the radius of the thermal plume. To avoid excessive diffusion of the thermal plume, a multi-module dynamic iterative coupled solution is performed every hour. If the error does not meet the threshold, the cylinder cut-off ratio of the cogeneration unit is adjusted. Or the flow rate of a thermal well pump.

[0088] The specific operation process of the pure condensing power generation mode during the non-heating season is as follows. First, environmental parameters for the non-heating season are collected and substituted into the building dynamic load model to solve for the building foundation electrical load. During this period, the building has no heat or cooling load. Then, the cogeneration unit is switched to pure condensing power generation mode, and the full-load power generation is calculated by substituting the values ​​into the cogeneration unit's variable operating condition model. This ensures that the power generation capacity of the combined heat and power unit is greater than or equal to the electrical load of the building foundation. Excess electricity was sold through grid 5. Subsequently, cold well pump 13, hot well pump 14, heating plate heat exchanger 3, and storage plate heat exchanger 4 were shut down, and all valves v1 to v14 were closed, cutting off all water and heat flow channels between the surface and underground. Finally, the initial temperature field of the reservoir was solved using a deep thermal reservoir seepage heat coupling model. It monitors reservoir temperature changes in real time, maintains reservoir stability, and does not perform heat storage or extraction operations.

[0089] Specific verification: This embodiment takes a 4.5 million square meter residential building cluster in North China as the application object. This area is a cold building climate zone with a minimum temperature of -15℃ and a maximum temperature of 38℃. The following is a detailed description of the main system parameters and model solution results of this embodiment.

[0090] The basic system parameters used in this embodiment are as follows: the combined heat and power unit has a rated power generation of 247MW and a rated heating capacity of 180MW; the deep thermal reservoir has a burial depth of 4000m, adopts a ring arrangement of 4 hot wells and 4 cold wells, with a well group spacing of 500m, and the reservoir permeability is 2mD to 25mD and the porosity is 0.01 to 0.15.

[0091] By solving the mathematical model of this invention, the relevant operating results of the building load can be obtained. The maximum heat load of the building is 177.2MW and the maximum electrical load is 224.5MW. The load curve solved by the model has a fitting degree of more than 98% with the actual load.

[0092] The model solution results for the combined heat and power (CHP) unit show that the peak shaving depth is 32.8%, the maximum power output is 30.3MW, and the overall efficiency of the CHP unit is [not specified]. It has remained stable at over 85%.

[0093] The model results for deep thermal energy storage show that the storage temperature is 80℃ to 115℃, the maximum thermal storage power is 36.7MW, the maximum heat extraction power is 50MW, and the energy storage efficiency after 20 years of system operation is [data missing]. The thermal plume radius reaches 0.906. At only 53.7m, there is no risk of thermal breakthrough.

[0094] The model solution results for the system's economic indicators show that the system's annual operating cost is 1.776 million yuan, the annual net income is 7.424 million yuan, and the initial investment payback period is 8.6 years.

[0095] This embodiment demonstrates that the aforementioned mathematical model accurately describes the dynamic characteristics of each unit in the system, and the model-based control method achieves effective coupling of source, load, and storage. The system's technical and economic performance is superior to the traditional decoupled steady-state operation mode. This embodiment's system, through dynamic coordinated control of source, load, and storage, achieves a good match between the building's dynamic load and the heat source and storage system. The alternating operation mode of daytime heat storage and nighttime heat extraction during the heating season effectively reduces heat loss. The coupled operation mode of ground and underground systems truly reflects the system's dynamic characteristics. Compared to the traditional decoupled steady-state operation mode, the system and control method of this invention achieve significant improvements in both technical and economic performance, fully meeting the needs of large-scale clean heating in North China.

[0096] See Figure 3-4 , Figure 3-4 The above is a comparison chart of the simulation results of the operation performance of the deep geothermal long-term energy storage system according to the embodiment of the present invention. It is used to verify the difference in operation performance between the technical solution of the present invention and the conventional technical solution. Mode 1 is the operation mode corresponding to the source-load-storage coupled deep geothermal long-term energy storage system control method adopted in the embodiment of the present invention, while Mode 2 and Mode 3 are the operation modes corresponding to conventional technologies.

[0097] Figure 3 (a) Includes a year-on-year comparison curve of DGES energy storage efficiency. The horizontal axis of the curve represents the number of years of operation, and the vertical axis represents the energy storage efficiency, showing the trend of energy storage efficiency changes for different modes over a 20-year operating cycle. Mode 1, corresponding to this embodiment of the invention, initially achieves an energy storage efficiency of approximately 0.67. Throughout the operating cycle, the energy storage efficiency steadily increases, stabilizing above 0.9 after 20 years. The overall energy storage efficiency remains at a high level and is superior to Modes 2 and 3 corresponding to conventional technologies. Mode 2 has an initial energy storage efficiency of approximately 0.38, gradually increasing during operation, reaching approximately 0.92 after 20 years. Mode 3 has an initial energy storage efficiency of approximately 0.29, but after 20 years, the energy storage efficiency only reaches approximately 0.75, far lower than the technical solution of this embodiment of the invention.

[0098] Figure 3 (b) Includes an hourly heating temperature comparison curve for DGES. The horizontal axis of this curve represents the operating time in hours (h), and the vertical axis represents the heating temperature in degrees Celsius (°C), demonstrating the heating temperature fluctuations during system operation under different modes. In Mode 1, corresponding to this embodiment of the invention, the heating temperature remains consistently around 105°C with minimal fluctuations, effectively matching the building's heating temperature requirements. In Mode 2, corresponding to conventional technology, the heating temperature fluctuates significantly, dropping to a minimum of around 98°C, failing to maintain consistent heating temperature. In Mode 3, corresponding to conventional technology, the overall heating temperature is too high with minor fluctuations, resulting in poor matching with the building's set heating temperature.

[0099] Figure 4 Includes the DGES thermal plume distribution cloud map for the 20th year, showing the thermal plume diffusion of the deep geothermal reservoir under different modes when the system has been running for 239 months. The mode corresponding to this embodiment of the invention is Mode 1 (…). Figure 4 (a) The thermal plume is concentrated only in a very small area around the hot well, effectively suppressing the spread of the thermal plume and eliminating the risk of thermal breakthrough. Mode 2 corresponding to conventional technology ( Figure 4 (b) The thermal plume diffusion range is significantly expanded, and the thermal plume radius is much larger than that of the technical solution in this embodiment of the invention. Mode 3 corresponding to conventional technology ( Figure 4 (c) The hot plume spreads over a wide area, covering most of the area between the hot and cold wells, posing a very high risk of thermal breakthrough.

[0100]

[0101] The DGES system technical and economic indicator comparison table details the performance and economic indicators of different modes over a 20-year operating cycle. Regarding energy storage performance, the total heat storage capacity of Mode 1 in this embodiment is 320.5 TJ over 20 years, only 49.6% of Mode 2 and 35.4% of Mode 3. The 20-year energy storage efficiency reaches 0.906, the average heating temperature over 20 years is 105℃, and the heat plume radius over 20 years is only 53.7m, a significant reduction compared to 156.8m for Mode 2 and 352.4m for Mode 3. In terms of economic performance, the total operating cost of Mode 1 corresponding to the embodiments of the present invention is RMB 35.515 million over 20 years, and the annual operating cost is RMB 1.776 million, which is only 49.6% of that of Mode 2 and 35.4% of that of Mode 3. The annual net income reaches RMB 7.424 million, which is 32.1% higher than that of Mode 2 and 77.1% higher than that of Mode 3. The initial investment payback period is only 8.6 years, which is 24.6% shorter than that of Mode 2 and 43.8% shorter than that of Mode 3.

[0102] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0103] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A source-load-storage coupled deep geothermal long-term energy storage system, characterized in that, include: The system comprises a deep geothermal storage unit, a combined heat and power (CHP) unit, a heating plate heat exchanger, a thermal storage plate heat exchanger, a power grid unit, a heating network unit, and a valve assembly. The CHP unit outputs electrical and thermal energy and is bidirectionally electrically connected to the power grid unit. The steam outlet and return water inlet of the CHP unit are connected to the primary side of the heating plate heat exchanger and the primary side of the thermal storage plate heat exchanger, respectively, via the valve assembly. The deep geothermal storage unit stores and releases geothermal energy and is connected to the secondary side of the thermal storage plate heat exchanger via the valve assembly. The heating network unit includes a supply water network and a return water network. The return water network is connected to the secondary side of the heating plate heat exchanger and the secondary side inlet of the thermal storage plate heat exchanger, respectively, via the valve assembly. The supply water network is connected to the secondary side of the heating plate heat exchanger and the secondary side outlet of the thermal storage plate heat exchanger, respectively, via the valve assembly. The valve assembly controls the on / off state and flow direction of each pipeline, with each valve installed on its corresponding connecting pipeline.

2. The source-load-storage coupled deep geothermal long-term energy storage system according to claim 1, characterized in that, The deep geothermal storage unit includes: The system includes a cold well, a hot well, a cold well pump, and a hot well pump. The cold well pump is installed inside the cold well, and the hot well pump is installed inside the hot well. The outlet of the cold well pump is connected to the secondary inlet pipe of the thermal storage plate heat exchanger via a twelfth valve, and the secondary outlet of the thermal storage plate heat exchanger is connected to the inlet pipe of the hot well via an eleventh valve. The outlet of the hot well pump is connected to the secondary inlet pipe of the thermal storage plate heat exchanger via an eleventh valve, and the secondary outlet of the thermal storage plate heat exchanger is connected to the inlet pipe of the cold well via a twelfth valve.

3. The source-load-storage coupled deep geothermal long-term energy storage system according to claim 1, characterized in that, The valve assembly includes: First valve, second valve, third valve, fourth valve, fifth valve, sixth valve, seventh valve, eighth valve, ninth valve, tenth valve, eleventh valve, twelfth valve, thirteenth valve, and fourteenth valve; the first valve is connected in series to the steam outlet main pipe of the cogeneration unit, and the second valve is connected in series to the return water inlet main pipe of the cogeneration unit; the third valve is connected in series to the pipe between the first valve and the primary heat exchanger inlet of the heating plate, and the fourth valve is connected in series to the pipe between the primary heat exchanger outlet of the heating plate and the second valve; the seventh valve is connected in series to the pipe between the first valve and the primary heat exchanger inlet of the thermal storage plate, and the eighth valve is connected in series to the... The pipeline is connected between the primary outlet of the heat exchanger and the second valve; the ninth valve is connected in series in the pipeline between the primary outlet of the heat exchanger and the primary inlet of the heat exchanger; the tenth valve is connected in series in the pipeline between the primary outlet of the heat exchanger and the outlet end of the seventh valve; the fifth valve is connected in series in the pipeline between the secondary outlet of the heat exchanger and the water supply network; the sixth valve is connected in series in the pipeline between the return water network and the secondary inlet of the heat exchanger; the thirteenth valve is connected in series in the pipeline between the return water network and the secondary inlet of the heat exchanger; and the fourteenth valve is connected in series in the pipeline between the secondary outlet of the heat exchanger and the water supply network.

4. The source-load-storage coupled deep geothermal long-term energy storage system according to claim 1, characterized in that, The cogeneration unit is a coal-fired cogeneration unit. The cogeneration unit adopts a condensing-heating medium-pressure cylinder exhaust steam supply mode. The extraction steam outlet of the cogeneration unit is connected to the inlet pipeline of the first valve.

5. A control method for a source-load-storage coupled deep geothermal long-term energy storage system, applicable to the system described in any one of claims 1 to 4, characterized in that, Including the following steps: The collected building environment parameters and system operating parameters are calculated and processed to obtain real-time building electric heating load data; Based on the real-time building electric heating load data, the operating periods for the heating season and non-heating season are divided, and corresponding variable operating condition strategies are generated for each period. Based on the aforementioned variable operating condition strategy, the cogeneration unit is adjusted to high load variable operating condition during the daytime heat storage period in the heating season, and heat storage control operation is performed on the deep heat storage. Based on the aforementioned variable operating condition strategy, the cogeneration unit is adjusted to low load variable operating condition during the nighttime heat extraction period in the heating season, and heat extraction and heating control operations are performed on the deep thermal storage. According to the aforementioned variable operating condition strategy, the cogeneration unit will be switched to pure condensing operation mode during the non-heating season, and well closure control operation will be performed on the deep thermal reservoir. By using a multi-module dynamic iterative coupling method, the operating parameters of system equipment and the opening degree of valve groups are adjusted in real time to achieve source-load-storage coordinated control.

6. The method according to claim 5, characterized in that, The process of calculating and processing the collected building environment parameters and system operating parameters to obtain real-time building electrical and heating load data includes: constructing a building dynamic load model using the lumped parameter method of 5 thermal resistance and 1 thermal capacity; discretizing time using the explicit Euler method; solving the building dynamic load model using the fourth-order Runge-Kutta method; and outputting real-time building heat load and electrical load data.

7. The method according to claim 5, characterized in that, The high-load variable operating condition adjustment of the cogeneration unit during the daytime heat storage period in the heating season, and the heat storage control operation of the deep heat storage, include: starting the cold well pump and shutting down the hot well pump and the heat exchanger; opening the corresponding valve group to connect the heat storage channel; constructing a variable operating condition mathematical model describing the coupling relationship between electricity, heat and fuel; using a sequential quadratic programming algorithm to solve the grid balance constraints; dynamically adjusting the pumping rate and load rate of the cogeneration unit; and completing the heat exchange between the cogeneration unit and the deep heat storage through the heat storage heat exchanger to realize the heat storage operation of the deep heat storage.

8. The method according to claim 5, characterized in that, The process of adjusting the cogeneration unit to low-load variable operating conditions during the nighttime heating period in the heating season and performing heat extraction and supply operations on the deep thermal storage includes: starting the hot well pump and the heat exchanger and shutting down the cold well pump; opening the corresponding valve group to connect the heat extraction and supply channels; discretizing the reservoir space of the coupled model using the finite volume method and combining it with the explicit Euler method to complete the discretization of the time dimension; solving the discretized coupled model hourly to dynamically adjust the heat extraction power of the deep thermal storage; using the heat exchanger to complete the heat exchange between the deep thermal storage and the return water of the heating network; and using the heat exchanger to reheat the return water of the heating network before delivering it to the building end, thereby realizing the heat extraction and supply operation of the deep thermal storage.

9. The method according to claim 5, characterized in that, The aforementioned switching of the cogeneration unit to pure condensing operation mode during the non-heating season and the execution of well-closure control operations for deep thermal reservoirs include adjusting the cogeneration unit to pure condensing operation mode for full-load power generation, shutting down the cold well pump, hot well pump, heating plate heat exchanger and storage plate heat exchanger, and closing all valves in the valve group to cut off the water and heat flow channels between the surface and underground, so as to keep the reservoir temperature field stable by keeping the deep thermal reservoir closed throughout the entire process.

10. The method according to claim 5, characterized in that, The method of using a multi-module dynamic iterative coupling to adjust the operating parameters of system equipment and valve group opening in real time includes solving the combined heat and power unit variable operating condition model, the building dynamic load model and the deep thermal storage infiltration heat transfer coupling model respectively, feeding back the solution results of each model to iterate until the temperature, flow rate and power errors of adjacent iteration steps meet the preset threshold, and automatically adjusting the equipment operating parameters and valve group opening based on the iteration results and monitoring data.

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