Solar energy coupled geothermal energy energy cascade utilization system and control method thereof

Abstract

This invention discloses a solar-geothermal energy cascade utilization system and its control method, comprising a solar thermal collector subsystem, a solar hot water circulation subsystem, a user and underground pipe subsystem, and a controller. The solar thermal collector subsystem includes a solar collector device, a first heat exchanger, and an insulated water tank. The solar hot water circulation subsystem includes a phase change heat storage device, a second heat exchanger, a third heat exchanger, a domestic hot water user terminal, an absorption chiller / heater unit, and an insulated water tank. The user and underground pipe subsystem includes a ground source heat pump, underground pipe assemblies, and user terminals for heating and cooling needs. Each subsystem utilizes the circulation pipeline and the control method to achieve corresponding heat exchange. Using this system, cooling, heating, and hot water production functions can be integrated, thereby reducing investment and construction costs. Using the system's control method, the energy cascade utilization of solar and geothermal resources can be achieved year-round, providing a stable source of heat and cold water, domestic hot water, and ensuring underground thermal balance.

Description

Technical Field

[0001] This invention relates to the field of new energy clean heating technology, specifically to an energy cascade utilization system and control method of solar coupled geothermal energy. Background Technology

[0002] Against the backdrop of energy shortages and increasingly serious environmental pollution, the use of clean energy is playing an increasingly important role.

[0003] Solar energy resources, with their abundance, lack of pollution, and environmental friendliness, have become a hot topic for utilization. Based on the characteristics of solar energy, it is currently mainly used for power generation, hot water production, heating, and cooling. Although solar energy resources are very abundant, their efficiency is unstable due to the influence of the seasons, time of day, and weather throughout the year. Furthermore, there is a mismatch between system energy demand and solar energy supply; for example, when solar radiation is strong, the system's demand for solar energy may be low, resulting in energy waste.

[0004] Geothermal energy also boasts advantages such as large reserves, wide distribution, cleanliness, environmental friendliness, and stability. Based on these characteristics, geothermal energy is currently primarily used for power generation and heating. While geothermal energy is stable, reliable, and has large reserves, its relatively low thermal quality results in low efficiency for energy conversion systems. Furthermore, when using geothermal energy solely for heating, it is gradually absorbed and converted over time. When subsequent geothermal energy cannot be effectively replenished, the heating efficiency of the geothermal heating system decreases progressively.

[0005] Currently, when using clean energy to achieve cooling, heating, or hot water functions, the cooling system is only used for cooling and the heating system is only used for heating. This results in the need to build two sets of operating equipment, leading to redundant construction and investment to meet various functional requirements, and causing a waste of resources.

[0006] Therefore, how to integrate cooling, heating and hot water supply functions to reduce construction and investment costs, while maximizing the utilization and conversion of solar energy and effectively supplementing geothermal energy based on the integration of various functions, is an urgent problem to be solved. Summary of the Invention

[0007] The purpose of this invention is to provide a solar-coupled geothermal energy cascade utilization system and its control method. Using this system, cooling, heating and hot water production functions can be integrated, thereby reducing investment and construction costs. Using the system control method, the energy gradient utilization of solar and geothermal energy resources can be realized throughout the year, providing a stable source of cold and heat and domestic hot water, while ensuring underground thermal balance.

[0008] The technical solution adopted by this invention to solve its technical problem is: a solar-coupled geothermal energy cascade utilization system, including a solar thermal collector subsystem, a solar hot water circulation subsystem, a user and underground pipe subsystem, and a controller; the solar thermal collector subsystem includes a solar collector device, a first heat exchanger, and an insulated water tank; the solar hot water circulation subsystem includes a phase change heat storage device, a second heat exchanger, a third heat exchanger, a domestic hot water user terminal, an absorption chiller / heater unit, and the insulated water tank; the user and underground pipe system includes a ground source heat pump, underground pipe assembly, and a user terminal for heating and cooling needs; the solar thermal collector device, the first heat exchanger, and the insulated water tank achieve corresponding heat exchange through a first circulation pipeline; the insulated water tank, the phase change heat storage device, the second heat exchanger, and the third heat exchanger achieve corresponding heat exchange through a second circulation pipeline; and the heat source drive side of the absorption chiller / heater unit achieves corresponding heat exchange through a third circulation pipeline. The loop pipe connects to the second circulation pipe. The second heat exchanger exchanges heat with the user end requiring hot or cold water via the fourth circulation pipe. The user side of the ground source heat pump connects to the fourth circulation pipe via the fifth circulation pipe. The condenser side of the absorption chiller connects to the cold or heat source input side of the ground source heat pump via the sixth circulation pipe. The evaporator side of the absorption chiller connects to the buried pipe group via the seventh circulation pipe. The fourth circulation pipe connects to the sixth and seventh circulation pipes via the eighth circulation pipe. The ninth circulation pipe connects to the sixth and seventh circulation pipes. The third heat exchanger connects to the domestic hot water user end via the tenth circulation pipe. The controller controls the operation of the absorption chiller, the ground source heat pump, the tenth circulation pipe, and the first to eighth circulation pipes.

[0009] Preferably, the first circulation pipeline includes a first pipeline, a second pipeline, a third pipeline, and a fourth pipeline. The first and second pipelines connect the solar thermal collector to the first heat exchanger. A first circulating water pump is connected in series on the second pipeline. The third and fourth pipelines connect the first heat exchanger to the insulated water tank. A second circulating water pump is connected in series on the fourth pipeline.

[0010] Furthermore, the second circulation pipeline includes a fifth pipeline, a sixth pipeline, a seventh pipeline, an eighth pipeline, and a ninth pipeline. The fifth pipeline connects the insulated water tank and the phase change heat storage device. The sixth pipeline connects the phase change heat storage device and the second heat exchanger. The seventh pipeline connects the second heat exchanger and the third heat exchanger. The eighth pipeline connects the third heat exchanger and the insulated water tank. The ninth pipeline is connected in series between the fifth and sixth pipelines. A V3 regulating valve is connected in series on the ninth pipeline. A third circulating water pump and a V1 switching valve are connected in series on the fifth pipeline, with the V1 switching valve located downstream of the connection between the ninth and fifth pipelines. A V2 switching valve and a V4 switching valve are connected in series on the sixth pipeline, with the V2 and V4 switching valves located upstream and downstream of the connection between the ninth and sixth pipelines, respectively. A V5 switching valve is connected in series on the seventh pipeline.

[0011] Furthermore, the third circulation pipeline includes a tenth pipeline and an eleventh pipeline. The heat source drive side of the absorption chiller unit is connected to the sixth pipeline through the tenth pipeline, and the connection point between the tenth pipeline and the sixth pipeline is located upstream of the V4 switch valve. The heat source drive side of the absorption chiller unit is connected to the sixth and seventh pipelines through the eleventh pipeline. The connection point between the eleventh pipeline and the sixth pipeline is located upstream of the V4 switch valve, and the connection point between the eleventh pipeline and the seventh pipeline is located upstream of the V5 switch valve. A V6 switch valve is connected in series on the eleventh pipeline section located between the sixth and seventh pipelines. A V7 switch valve and a V8 switch valve are connected in series on the tenth pipeline and the eleventh pipeline, respectively.

[0012] Furthermore, the fourth circulation pipeline includes a twelfth pipeline and a thirteenth pipeline. The twelfth and thirteenth pipelines connect the second heat exchanger to the user side with heating and cooling requirements. A V10 switch valve is connected in series on the twelfth pipeline, and a V9 switch valve and a fifth circulating water pump are connected in series on the thirteenth pipeline. The fifth circulation pipeline includes a fourteenth pipeline and a fifteenth pipeline. The user side of the ground source heat pump connects to the twelfth and thirteenth pipelines through the fourteenth pipeline. The connection point between the fourteenth and twelfth pipelines is located downstream of the V10 switch valve, and the connection point between the fourteenth and thirteenth pipelines is located upstream of the V9 switch valve. A V19 switch valve is connected in series on the section of the fourteenth pipeline located between the twelfth and thirteenth pipelines. A V11 switch valve and a V12 switch valve are connected in series on the fourteenth and fifteenth pipelines, respectively.

[0013] Furthermore, the sixth circulation pipeline includes a sixteenth pipeline and a seventeenth pipeline, which connect the cold and heat source input side of the ground source heat pump to the condenser side of the absorption chiller unit. A V14 switch valve and a V13 switch valve are connected in series on the sixteenth pipeline and the seventeenth pipeline, respectively. The seventh circulation pipeline includes an eighteenth pipeline and a nineteenth pipeline, which connect the buried pipe assembly to the evaporator side of the absorption chiller unit. A fourth circulation water pump is connected in series on the eighteenth pipeline.

[0014] Furthermore, the eighth circulation pipeline includes a twentieth pipeline and a twenty-first pipeline. One end of the twentieth pipeline is connected to the thirteenth pipeline, and the other end of the twentieth pipeline is connected in parallel to the V16 three-way switch valve on the sixteenth pipeline and the V18 three-way switch valve on the nineteenth pipeline. One end of the twenty-first pipeline connects the twelfth and thirteenth pipelines, and a V20 switch valve is connected in series on the section of the twenty-first pipeline connecting the twelfth and thirteenth pipelines. The connection between the twenty-first and thirteenth pipelines is located downstream of the fifth circulating water pump. A V21 switch valve is connected in series on the thirteenth pipeline, and the V21 switch valve is located at the twenty-first pipeline. The connection between the pipeline and the thirteenth pipeline is between the thirteenth pipeline and the twentieth pipeline; the other end of the twentieth pipeline is connected in parallel to the V15 three-way switch valve on the seventeenth pipeline and the V17 three-way switch valve on the eighteenth pipeline; the ninth circulation pipeline includes the twenty-second pipeline and the twenty-third pipeline, the twenty-second pipeline connects the seventeenth pipeline and the eighteenth pipeline, and the twenty-third pipeline connects the sixteenth pipeline and the nineteenth pipeline; the tenth circulation pipeline includes the twenty-fourth pipeline and the twenty-fifth pipeline, the twenty-fourth pipeline and the twenty-fifth pipeline connect the third heat exchanger and the domestic hot water user end, and a sixth circulation water pump is connected in series on the twenty-fifth pipeline.

[0015] Furthermore, a first temperature sensor for monitoring the outlet water temperature of the solar thermal collector is installed on the first pipeline; a second temperature sensor for monitoring the water temperature inside the insulated water tank is installed on the insulated water tank; a third temperature sensor for monitoring the molten salt temperature is installed on the phase change heat storage device; a fourth temperature sensor for monitoring the outlet water temperature of the phase change heat storage device is installed on the sixth pipeline; a fifth temperature sensor for monitoring the outlet water temperature at the user end of the heating and cooling demand is installed on the thirteenth pipeline; and a sixth temperature sensor for monitoring the return water temperature of the second heat exchanger is installed on the seventh pipeline. The solar thermal collector is a solar collector, the phase change heat storage device is a phase change heat storage device, the absorption chiller is an absorption heat pump, and the first to third heat exchangers are all plate heat exchangers.

[0016] This invention also provides an operation control method for a solar-coupled geothermal energy cascade utilization system, comprising the following steps:

[0017] S1. Check all relevant operating components within the system to ensure that each component is capable of normal operation.

[0018] S2. Start the controller. After the controller starts, the operator will enter the operation mode selection interface through the start screen.

[0019] S3. Operators can adjust the system's operation mode (heating, insulation, cooling, or geothermal well storage) based on the real-time season.

[0020] 10. The operation control method for a solar-coupled geothermal energy cascade utilization system according to claim 9, characterized in that,

[0021] S3.1 The operation control logic of the heating mode is as follows: When the system enters the heating operation mode, the operator sets the values ​​of Ta1-Ta6 in sequence; Ta1 is the solar collector circulation temperature difference; Ta2 is the heat storage device start-up temperature; Ta3 is the absorption chiller / heater unit drive temperature; Ta4 is the domestic hot water supply set temperature; Ta5 is the user-side return water set temperature; Ta6 is the heat storage device release start-up temperature; after setting the above values, the controller controls each valve according to the set program, that is, opens the V3, V6 and V19 switch valves, opens V15 and V16 to the bc passage state; opens V17 and V18 to the ab passage state, and the controller simultaneously operates the solar collector subsystem, the solar hot water circulation subsystem and the user and underground pipe subsystem;

[0022] When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time. T1 is the outlet water temperature of the solar thermal collector; T2 is the hot water temperature of the insulated water tank. At the same time, the controller compares T1-T2 with Ta1 in real time. When T1-T2≥Ta1, the first and second circulating water pumps are running; when T1-T2<Ta1, the first and second circulating water pumps are stopped.

[0023] During the operation of the solar water heating circulation subsystem, the controller monitors the values ​​of T2, T3, and T4 in real time. T3 is the molten salt temperature of the heat storage device, and T4 is the downstream water temperature of the heat storage device. Simultaneously, the controller compares T2 with T4 in real time. When T2 ≥ T4, the third circulating water pump starts. Then, T2 is compared with T2 and T3. When T2 ≥ T2, the phase change heat storage process begins. At this time, the V1 and V2 switching valves open, and the opening of the V3 regulating valve is adjusted to decrease according to the set requirements. During the phase change heat storage process, T4 is compared with T3. When T4 ≥ T3, the heating flow of the absorption chiller unit begins. In the next phase change heat storage process, valves V7 and V8 are opened, while valve V6 is closed. When T4 < Ta3, the phase change heat storage process is stopped. At this time, valves V1 and V2 are closed, and valve V3 is fully opened. Then, the absorption chiller heating process is resumed. When Ta2 > T2 ≥ Ta3, the system directly enters the absorption chiller heating process. When T2 < Ta3, T3 and Ta6 are compared again. When T3 ≥ Ta6, the phase change heat release process begins. At this time, valves V1 and V2 are opened, and the opening of valve V3 is adjusted to be smaller according to the set requirements. When T3 < Ta6, the process directly... The system initiates the domestic hot water supply mode. During the phase change heat release process, T4 is compared with Ta3. When T4 ≥ Ta3, the system operates the absorption chiller heating process. When T4 < Ta3, the system first stops the phase change heat release process. At this time, valves V1 and V2 are closed, and valve V3 is fully open. Then, the domestic hot water supply mode is activated. After the system operates the absorption chiller heating process, the domestic hot water supply mode is activated, providing domestic hot water to users. When T2 < Ta4, the comparison between T3 and Ta6 continues. When T3 ≥ Ta3... At 6:00, the phase change heat release process begins. At this time, valves V1 and V2 are opened, and the opening of regulating valve V3 is adjusted to be smaller according to the set requirements. During the phase change heat release process, T6 and Ta4 are compared. T6 is the outlet water temperature after heat exchange in the second heat exchanger. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the operation of the third circulating water pump is stopped, and valves V3 and V6 are opened while valves V1, V2, V7, and V8 are closed. When T3 < Ta6, the operation of the third circulating water pump is stopped, and valves V3 and V6 are opened while valves V1, V2, V7, and V8 are closed.

[0024] When operating the user and underground pipe subsystem, the fourth and fifth circulating water pumps are started. Simultaneously, the value of T5 is monitored in real time, and the value of Ta5 (the user-side return water temperature) is automatically adjusted according to a set program based on the ambient temperature. The system calculates whether T5 equals Ta5. If T5 = Ta5, the fourth and fifth circulating water pumps 204 and 205 remain running. If T5 is not equal to Ta5, and if T5 > Ta5, the system checks whether the ground source heat pump 109 is running. If the ground source heat pump 109 is running, its operating load is reduced. During operation, V19 switch valve 319 is opened while V11-V14 switch valves are closed. Then, the operating load of the absorption chiller unit 108 is reduced to decrease the load. When T5 is not equal to Ta5, if T5 < Ta5, then under the current driving heat source, it is determined whether the absorption chiller unit 108 is at its maximum load. If it is at its maximum load, the ground source heat pump 109 is started. At this time, V19 switch valve 319 is closed, while V11-V14 switch valves are opened. Then, the operating load of the ground source heat pump 109 is increased to increase the load. If it is not at its maximum load, the operating load of the absorption chiller unit 108 is increased to increase the load.

[0025] The operating control logic of the heat preservation mode described in S3.2 is as follows: When the system enters the heat preservation mode, the operator sets the values ​​of Ta1, Ta2, Ta5, and Ta6 in sequence; after the setting is completed, the controller controls each valve according to the set program, that is, opens the on / off valves V3, V4, V5, V9, V10, and V21. Then, the controller synchronously operates the solar thermal collector subsystem, the solar hot water circulation subsystem, and the user and underground pipe subsystem.

[0026] When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time, and compares T1-T2 with Ta1 in real time. When T1-T2≥Ta1, the first and second circulating water pumps are running; when T1-T2<Ta1, the first and second circulating water pumps are stopped.

[0027] When operating the solar water heating circulation subsystem and the user and underground pipe subsystem, the controller determines whether T5 is less than Ta5. If T5 < Ta5, it continues to compare T2 with Ta5. If T2 ≥ Ta5, the third circulating water pump 203 is activated. During the operation of the third circulating water pump 203, T2 is compared with Ta2. If T2 ≥ Ta2, the phase change heat storage process begins. At this time, the V1 and V2 switching valves open, and the opening of the V3 regulating valve 303 is adjusted to decrease according to the set requirements. During the heat treatment process, T4 is compared with Ta5. When T4 ≥ Ta5, the fifth circulating water pump 205 is run alone. When T4 < Ta5, the phase change heat storage process is stopped. At this time, the V1 and V2 switching valves are closed, while the V3 regulating valve is fully open. Then, the fifth circulating water pump is run alone again. When comparing T2 with Ta2, if T2 < Ta2, the fifth circulating water pump is run alone. When comparing T2 with Ta5, if T2 < Ta5, then T3 is compared with Ta6. When T3 ≥ Ta6, ... The third circulating water pump then operates, and the phase change heat release process begins. At this time, valves V1 and V2 are opened, and the opening of regulating valve V3 is adjusted to be smaller according to the set requirements. During the phase change heat release process, T4 and Ta5 are compared. When T4 ≥ Ta5, the ground source heat pump heating process begins, and the fifth circulating water pump operates alone. When T4 < Ta5, the ground source heat pump, the fourth circulating pump, and the fifth circulating pump are started, valves V11-V14 are opened, regulating valve V3 is fully opened, and valves V1, V2, and V9 are closed. The system operates by using the V10 switching valve and the third circulating water pump. When comparing T3 and Ta6, if T3 < Ta6, the system enters the ground source heat pump heating process. After the fifth circulating water pump is turned on, the second heat exchanger enters the heat exchange working state. When the system determines whether T5 is less than Ta5, if T5 ≥ Ta5, the system stops operating. At this time, the V9 and V10 switching valves are opened, the V3 regulating valve opening is at its maximum, and the V1, V2, and V11-V14 switching valves are closed, stopping the operation of the third, fourth, and fifth circulating water pumps.

[0028] The operation control logic of the cooling mode described in S3.3 is as follows: When the system enters the cooling operation mode, the operator sets the values ​​of Ta1-Ta6 in sequence; after the above values ​​are set, the controller controls each valve according to the set program, that is, opens the on / off valves V3, V6 and V19, opens V15 and V16 to the ab passage state, and opens V17 and V18 to the bc passage state; the controller simultaneously operates the solar thermal collector subsystem, the solar hot water circulation subsystem and the user and underground pipe subsystem.

[0029] When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time; at the same time, the controller compares T1-T2 with Ta1 in real time; when T1-T2≥Ta1, the first circulating water pump 201 and the second circulating water pump 202 are running; when T1-T2<Ta1, the operation of the first circulating water pump 201 and the second circulating water pump 202 is stopped.

[0030] During the operation of the solar water heating circulation subsystem, the controller monitors the values ​​of T2, T3, and T4 in real time, and simultaneously compares T2 with Ta4. When T2 ≥ Ta4, the third circulating water pump is activated. Then, T2 is compared with Ta2 and Ta3. When T2 ≥ Ta2, the phase change heat storage process begins. At this time, valves V1 and V2 are opened, and the opening of regulating valve V3 is adjusted to be smaller according to the set requirements. During the phase change heat storage process, T4 is compared with Ta3. When T4 ≥ Ta3, the absorption chiller cooling process begins. At this time, valves V7 and V8 are opened. When T4 < Ta3, the phase change heat storage process is stopped. At this time, the V1 and V2 switch valves are closed, and the V3 regulating valve is fully opened. Then, the absorption chiller cooling process is resumed. When Ta2 > T2 ≥ Ta3, the system directly enters the absorption chiller cooling process. When T2 < Ta3, T3 and Ta6 are compared again. When T3 ≥ Ta6, the phase change heat release process is started. At this time, the V1 and V2 switch valves are opened, and the opening of the V3 regulating valve is adjusted to be smaller according to the set requirements. When T3 < Ta6, the domestic hot water supply mode is directly started. During the phase change heat release process, T4 is compared with Ta3. When T4 ≥ Ta3, the system operates the absorption chiller cooling process. When T4 < Ta3, the system first stops the phase change heat release process. At this time, the V1 and V2 switching valves are closed, and the V3 regulating valve is fully open. Then, the domestic hot water supply mode is activated. After the system operates the absorption chiller cooling process, the system activates the domestic hot water supply mode, which provides domestic hot water to users. When T2 < Ta4, the comparison between T3 and Ta6 continues. When T3 ≥ Ta6, the system activates the absorption chiller cooling process. The third circulating water pump then enters the phase change heat release process. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve is adjusted to be smaller according to the set requirements. In the phase change heat release process, T6 and Ta4 are compared. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the operation of the third circulating water pump 203 is stopped, and at the same time, the V3 and V6 valves are opened and the V1, V2, V7 and V8 valves are closed. When T3 < Ta6, the operation of the third circulating water pump 203 is stopped, and at the same time, the V3 and V6 valves are opened and the V1, V2, V7 and V8 valves are closed.

[0031] When operating the user and underground pipe subsystem, the fourth circulating water pump 204 and the fifth circulating water pump 205 are started. Simultaneously, the value of T5 is monitored in real time, and the value of Ta5 (the user-side return water temperature) is automatically adjusted according to a set program based on the ambient temperature. The system calculates whether T5 equals Ta5. If T5 = Ta5, the fourth and fifth circulating water pumps 204 and 205 continue operating. If T5 is not equal to Ta5, and if T5 > Ta5, it checks whether the ground source heat pump 109 is operating. If the ground source heat pump 109 is operating, its operating load is reduced to decrease the load. When not in operation, open switch valve 319 (V19) and simultaneously close switch valves V11-V14. Then, reduce the operating load of the absorption chiller unit 108 to lower the load. When T5 is not equal to Ta5, if T5 < Ta5, determine whether the absorption chiller unit 108 is at its maximum load under the current driving heat source. If it is at its maximum load, start the ground source heat pump 109. At this time, close switch valve 319 (V19) and simultaneously open switch valves V11-V14. Then, increase the operating load of the ground source heat pump 109 to increase the load. If it is not at its maximum load, increase the operating load of the absorption chiller unit 108 to increase the load.

[0032] The geothermal well heat storage mode operation control logic described in S3.4 is as follows: When the system enters the geothermal well heat storage operation mode, the operator sets Ta1, Ta2, Ta4, Ta6, and Ta7 in sequence; Ta7 is the operating start temperature of the second heat exchanger 105; after setting the above values, the controller controls each valve according to the set program, that is, opens the on / off valves V3, V6, V9, V10, and V20, and opens V15, V16 or V17, V18 to the ac passage state. The controller simultaneously operates the solar thermal collector subsystem, the solar hot water circulation subsystem, and the user and buried pipe subsystem.

[0033] When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time; at the same time, the controller compares T1-T2 with Ta1 in real time; when T1-T2≥Ta1, the first and second circulating water pumps are running; when T1-T2<Ta1, the first and second circulating water pumps are stopped.

[0034] During the operation of the solar water heating circulation subsystem and the underground pipe subsystem, the controller monitors the values ​​of T2, T3, T4, and T6 in real time. Simultaneously, the controller compares T2 with Ta4 in real time. When T2 ≥ Ta4, the third circulating water pump starts. Then, T2 is compared with Ta2 and Ta7. When T2 ≥ Ta2, the phase change heat storage process begins. At this time, the V1 and V2 switching valves open, and the opening of the V3 regulating valve is adjusted to decrease according to the set requirements. During the phase change heat storage process, T4 is compared with Ta7. When T4 ≥ Ta7, the second heat exchanger heat exchange mode is entered. In the second heat exchanger heat exchange mode, the second heat exchanger performs heat exchange. 4. With valve V5 open and valve V6 closed, when T4 < Ta7, the phase change heat storage process stops. At this time, valves V1 and V2 are closed, and valve V3 is fully opened. Then, the system enters the second heat exchanger mode. When Ta2 > T2 ≥ Ta7, the system directly enters the second heat exchanger mode. When T2 < Ta7, T3 and Ta6 are compared again. When T3 ≥ Ta6, the phase change heat release process begins. At this time, valves V1 and V2 are opened, and the opening of valve V3 is adjusted to be smaller according to the set requirements. When T3 < Ta6, the domestic hot water supply mode is directly activated. During the phase change heat release process... The system compares T4 with Ta7. When T4 ≥ Ta7, the system operates in the second heat exchanger mode. When T4 < Ta7, the system first stops the phase change heat release process. At this time, valves V1 and V2 are closed, and valve V3 is fully open. Then, the domestic hot water supply mode is activated. After the system enters the second heat exchanger mode, T6 is compared with Ta4. When T6 ≥ Ta4, the domestic hot water supply mode is directly activated. When T6 < Ta4, the fourth circulating water pump stops. At this time, valve V6 is opened, and valves V4 and V5 are closed. Then, the domestic hot water supply mode is activated again. When T2 < Ta4, the process continues. The system compares T3 with Ta6. When T3 ≥ Ta6, the third circulating water pump is activated, and the phase change heat release process begins. At this time, valves V1 and V2 are opened, and the opening of valve V3 is adjusted to be smaller according to the set requirements. During the phase change heat release process, T6 is compared with Ta4. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the third circulating water pump stops operating, and valves V3 and V6 are opened while valves V1, V2, V4, and V5 are closed. When T3 < Ta6, the third circulating water pump stops operating, and valves V3 and V6 are opened while valves V1, V2, V7, and V8 are closed.

[0035] The beneficial effects of this invention are:

[0036] This system integrates cooling and heating functions using absorption chillers and solar collectors to produce domestic hot water. Therefore, the combination of absorption chillers and solar collectors effectively unifies cooling, heating, and hot water production, thereby reducing investment and construction costs and avoiding waste of resources. Furthermore, by utilizing the system's operation and control methods, solar energy and hot water with different temperature gradients can be fully utilized throughout the year, achieving multifunctionality and improving the utilization rate and economy of the solar energy system.

[0037] During the summer and transitional seasons, this system can supplement geothermal energy, thereby achieving geothermal balance and enabling the use of geothermal energy throughout the year. This can effectively guarantee the COP of the ground source heat pump (COP is often used to represent the ratio of the cooling or heating capacity that a heat pump system can achieve to the input power. Under the same conditions, the larger the ratio, the higher the efficiency and energy saving of the heat pump system).

[0038] Phase change thermal storage devices can store excess heat and release it when heat is insufficient, adjusting fluctuating solar energy resources, smoothing out peaks and filling valleys to meet usage needs; at the same time, phase change thermal storage has a high thermal density per unit volume, which can save space.

[0039] The working fluid used in absorption chiller units is a non-chlorofluorocarbon compound, which does not damage the atmospheric ozone layer and is beneficial to environmental protection. The absorption chiller unit system has fewer moving parts, the operating environment is relatively quiet, and the noise pollution is very low.

[0040] The use of solar energy and absorption chiller units reduces the start-up time of ground source heat pumps, reduces electricity consumption, and reduces operating costs. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a system flowchart of the present invention;

[0043] Figure 2 This is the heating mode control logic diagram of the present invention;

[0044] Figure 3 This is the heat preservation mode control logic diagram of the present invention;

[0045] Figure 4 This is the cooling mode control logic diagram of the present invention;

[0046] Figure 5 This is the control logic diagram for the geothermal well heat storage mode of the present invention;

[0047] In the diagram: 101 Solar thermal collector, 102 First heat exchanger, 103 Insulated water tank, 104 Phase change thermal storage device, 105 Second heat exchanger, 106 Third heat exchanger, 107 Domestic hot water user terminal, 108 Absorption chiller / heater unit, 109 Ground source heat pump, 110 Buried pipe assembly, 111 Heating / cooling demand user terminal, 201 First circulating water pump, 202 Second circulating water pump, 203 Third circulating water pump, 204 Fourth circulating water pump, 205 Fifth circulating water pump, 206 Sixth circulating water pump, 207 Seventh circulating water pump, 301 V1 switch valve, 302 V2 switch valve, 303 V3 regulating valve, 304 V4 switch valve, 305 V5 switch valve, 306 V6 switch valve, 307 V7 switch valve, 308 V8 switch valve, 309 V9 switch valve, 310 V10 switch valve, 311 V11 switch valve, 312 V12 switch valve, 313V13 switch valve, 314V14 switch valve, 315V15 three-way switch valve, 316V16 three-way switch valve, 317V17 three-way switch valve, 318V18 three-way switch valve, 319V19 switch valve, 320 V20 Switch Valve, 401 First Pipe, 402 Second Pipe, 403 Third Pipe, 404 Fourth Pipe, 405 Fifth Pipe, 406 Sixth Pipe, 407 Seventh Pipe, 408 Eighth Pipe, 409 Ninth Pipe, 410 Tenth Pipe, 411 Eleventh Pipe, 412 Twelfth Pipe, 413 Thirteenth Pipe, 414 Fourteenth Pipe, 415 Fifteenth Pipe, 416 Sixteenth Pipe, 417 Seventeenth Pipe, 418 Eighteenth Pipe, 419 Nineteenth Pipe, 420 Twentieth Pipe, 421 Twenty-first Pipe, 422 Twenty-second Pipe, 423 Twenty-third Pipe, 424 Twenty-fourth Pipe, 425 Twenty-fifth Pipe, 501 First Temperature Sensor, 502 Second Temperature Sensor, 503 Third Temperature Sensor, 504 Fourth Temperature Sensor, 505 Fifth Temperature Sensor. Detailed Implementation

[0048] The following will describe specific embodiments and appendices. Figure 1-5 The technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only some preferred embodiments of the present invention, and not all embodiments. Those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0049] This invention provides a solar-coupled geothermal energy cascade utilization system, characterized by comprising a solar thermal collector subsystem, a solar hot water circulation subsystem, a user and underground pipe subsystem, and a controller. The solar thermal collector subsystem is mainly used for the absorption and storage of solar energy. The solar hot water circulation subsystem mainly converts and outputs the energy absorbed and stored by the solar thermal collector subsystem, and also has a hot water production function. The user and underground pipe system is mainly used for geothermal extraction and meeting the user's heating and cooling needs. The solar thermal collector subsystem includes a solar collector device 101, a first heat exchanger 102, and an insulated water tank 103. In practical applications, the solar collector device 101 absorbs solar heat, and then... The heat is transported through pipelines to the first heat exchanger 102, which then uses pipelines to transfer the heat to the insulated water tank 103. The water in the insulated water tank 103 absorbs the heat, causing its temperature to rise and thus storing the heat. The solar water heating circulation subsystem includes a phase change heat storage device 104, a second heat exchanger 105, a third heat exchanger 106, a domestic hot water user terminal 107, an absorption chiller unit 108, and the insulated water tank 103. In practical applications, both the insulated water tank 103 and the phase change heat storage device 104 are used for outputting the stored heat. Under different temperature conditions, the insulated water tank 103 and the phase change heat storage device 104 can output heat at different stages according to set conditions. For example, when the temperature inside the insulated water tank 103... Highly, the heat in the insulated water tank 103 can directly provide heat to the phase change heat storage device 104, the domestic hot water user terminal 107, and the absorption chiller unit 108 in sequence. When the temperature in the insulated water tank 103 cannot meet the heat storage conditions of the phase change heat storage device 104, the insulated water tank 103 and the phase change heat storage device 104 can be combined to provide heat to the domestic hot water user terminal 107 and the absorption chiller unit 108. The user and underground pipe subsystem includes a ground source heat pump 109, an underground pipe assembly 110, and a user terminal 111 for heating and cooling needs. The ground source heat pump 109 is mainly used to realize the conversion of geothermal energy, and the underground pipe assembly 110 is used for the absorption and replenishment of geothermal energy. In practical applications, the underground pipe assembly 110 is usually combined with the geothermal... The solar collector 101, the first heat exchanger 102, and the insulated water tank 103 exchange heat through a first circulation pipeline. In practical applications, the solar collector 101 can be a solar collector already available on the market, and the first heat exchanger 102 can be a plate heat exchanger already available on the market. The insulated water tank 103, the phase change heat storage device 104, the second heat exchanger 105, and the third heat exchanger 106 exchange heat through a second circulation pipeline. In practical applications, the phase change heat storage device 104 can be a phase change heat storage device already available on the market. The second heat exchanger 105 and the third heat exchanger 106 can also use existing plate heat exchangers as the specific components.The absorption chiller unit 108 primarily utilizes a heat source to convert energy, resulting in low electricity consumption. In practical applications, the absorption chiller unit 108 can directly utilize commercially available absorption heat pumps as its implementation components. The heat source drive side of the absorption chiller unit 108 is connected to the second circulation pipeline via a third circulation pipeline. The second heat exchanger 105 and the user end 111 with heating and cooling demands are connected via a fourth circulation pipeline. The user side of the ground source heat pump 109 is connected to the fourth circulation pipeline via a fifth circulation pipeline. The condenser side of the absorption chiller unit 108 is connected to the heat source input side of the ground source heat pump 109 via a sixth circulation pipeline. The evaporator side of the absorption chiller unit 108 is connected to the buried pipe assembly 110 via a seventh circulation pipeline. The fourth circulation pipeline is connected via an eighth circulation pipeline. The circulation pipeline connects to the sixth and seventh circulation pipelines; the ninth circulation pipeline connects to the sixth and seventh circulation pipelines; the third heat exchanger 106 connects to the domestic hot water user terminal 107 via the tenth circulation pipeline, and the heat in the third heat exchanger 106 is continuously input to the domestic hot water user terminal 107 through the tenth circulation pipeline. At this time, the hot water in the domestic hot water user terminal 107 can be directly used to meet domestic needs. In practical applications, in order to ensure the water balance in the domestic hot water user terminal 107, a seventh circulation water pump 207 is added to the domestic hot water user terminal 107 side to realize the water replenishment function of the domestic hot water user terminal 107; the controller is used to control the operation of the absorption chiller unit 108, the ground source heat pump 109, the tenth circulation pipeline, and the first to eighth circulation pipelines. This system integrates cooling and heating functions using absorption chillers and solar collectors to produce domestic hot water. Therefore, the combination of absorption chillers and solar collectors effectively unifies cooling, heating, and hot water production, reducing investment and construction costs and avoiding waste of resources. Furthermore, the system's operation and control methods allow for year-round full utilization of solar energy and the generation of hot water at different temperature gradients, achieving multi-functionality and improving both the utilization rate and economic efficiency of the solar energy system.

[0050] Based on the above embodiments, the specific implementation of the first circulation pipeline is as follows: The first circulation pipeline includes a first pipeline 401, a second pipeline 402, a third pipeline 403, and a fourth pipeline 404. The first pipeline 401 and the second pipeline 402 connect the solar collector 101 to the first heat exchanger 102. A first circulating water pump 201 is connected in series on the second pipeline 102. The first circulating water pump 201 enables the water in the solar collector 101 to circulate between the collector and the first heat exchanger 102. The characteristics of the first heat exchanger 201 are used to realize the solar collector... The heat output of the water in the container 101 is achieved by the third pipe 403 and the fourth pipe 404 connecting the first heat exchanger 102 and the insulated water tank 103. A second circulating water pump 202 is connected in series on the fourth pipe 404. The second circulating water pump 202 enables the water in the insulated water tank 103 to circulate between the first heat exchanger 102 and the insulated water tank 103. By utilizing the characteristics of the first heat exchanger 102, heat exchange is achieved between the solar collector 101 and the insulated water tank 103, thereby storing the solar heat absorbed by the solar collector 101 in the insulated water tank 103 in the form of hydrothermal energy.

[0051] Further, the specific implementation of the second circulation pipeline is as follows: The second circulation pipeline includes a fifth pipeline 405, a sixth pipeline 406, a seventh pipeline 407, an eighth pipeline 408, and a ninth pipeline 409. The fifth pipeline 405 connects the insulated water tank 103 and the phase change heat storage device 104; the sixth pipeline 406 connects the phase change heat storage device 104 and the second heat exchanger 105; the seventh pipeline 407 connects the second heat exchanger 105 and the third heat exchanger 106; the eighth pipeline 408 connects the third heat exchanger 106 and the insulated water tank 103; the ninth pipeline 409 is connected in series between the fifth pipeline 405 and the sixth pipeline 406; and a V3 regulating valve 303 is connected in series on the ninth pipeline 409. During use, when the phase change heat storage device 104 is not releasing or storing heat, the V3 regulating valve 303 is adjusted to the fully open state. A third circulating water pump 203 and a V1 switching valve 301 are connected in series on the fifth pipe 405, and the V1 switching valve 301 is located downstream of the connection between the ninth pipe 409 and the fifth pipe 405. When the V1 switching valve 301 is opened, the third circulating water pump 203 can transport the water in the heat preservation tank 103 to the phase change heat storage device 104. A V2 switching valve 302 and a V4 switching valve 304 are connected in series on the sixth pipe 406, and the V2 switching valve 302 and the V4 switching valve 304 are located upstream and downstream of the connection between the ninth pipe 409 and the sixth pipe 406, respectively. A V5 switching valve 305 is connected in series on the seventh pipe 407. Using the second circulation pipeline, heat in the insulated water tank 103 can be transferred to the phase change heat storage device 104, the second heat exchanger 105, and the third heat exchanger 106. Heat in the phase change heat storage device 104 can also be transferred to the second heat exchanger 105 and the third heat exchanger 106. The phase change heat storage device can store excess heat and release it when heat is insufficient, adjusting fluctuating solar energy resources, smoothing peaks and filling valleys to meet usage needs. At the same time, the phase change heat storage has a high thermal density per unit volume, which can save space.

[0052] Further, the specific implementation of the third circulation pipeline is as follows: the third circulation pipeline includes a tenth pipeline 410 and an eleventh pipeline 411. The heat source driving side of the absorption chiller 108 is connected to the sixth pipeline 406 through the tenth pipeline 410, and the connection point between the tenth pipeline 410 and the sixth pipeline 406 is located upstream of the V4 switch valve 304. The tenth pipeline 410 serves as the driving heat source inflow pipe for the absorption chiller 108. The heat source driving side of the absorption chiller 108 is connected to the sixth pipeline 406 and the seventh pipeline 407 through the eleventh pipeline 411. The eleventh pipeline 411... The connection point between the 1st and 6th pipe 406 is located upstream of the V4 switch valve 304. The connection point between the 11th pipe 411 and the 7th pipe 407 is located upstream of the V5 switch valve 305. A V6 switch valve 306 is connected in series on the section of the 11th pipe 411 located between the 6th and 7th pipe 407. In practical applications, a V7 switch valve 307 and a V8 switch valve 308 are connected in series on the 10th and 11th pipes, respectively. When the absorption chiller unit 108 needs to work, the V6 switch valve 306 needs to be closed, while the V7 switch valve 307 and the V8 switch valve 308 are opened simultaneously.

[0053] Further, the specific implementation of the fourth circulation pipeline is as follows: The fourth circulation pipeline includes a twelfth pipeline 412 and a thirteenth pipeline 413. The twelfth pipeline 412 and the thirteenth pipeline 413 connect the second heat exchanger 105 to the user end 111 with heating and cooling demand. A V10 switching valve 310 is connected in series on the twelfth pipeline 412. A V9 switching valve 309 and a fifth circulating water pump 205 are connected in series on the thirteenth pipeline 413. The fifth circulating water pump 205 is used to realize the return water flow of the user end 111 with heating and cooling demand. The fifth circulation pipeline includes a fourteenth pipeline 414 and a fifteenth pipeline 415. The user side of the ground source heat pump 109 is connected through the fourteenth pipeline 414. To achieve connection with the twelfth pipe 412 and the thirteenth pipe 413, the connection point of the fourteenth pipe 414 and the twelfth pipe 412 is located downstream of the V10 switch valve 310, and the connection point of the fourteenth pipe 414 and the thirteenth pipe 413 is located upstream of the V9 switch valve 309. A V19 switch valve 319 is connected in series on the pipe section of the fourteenth pipe 414 located between the twelfth pipe 412 and the thirteenth pipe 413. A V11 switch valve 311 and a V12 switch valve 312 are connected in series on the fourteenth pipe and the fifteenth pipe, respectively. When the ground source heat pump 109 is turned on, the V19 switch valve 319 is closed, and the V11 switch valve 3111 and the V12 switch valve 312 are opened.

[0054] Further, the specific implementation of the sixth circulation pipeline is as follows: the sixth circulation pipeline includes a sixteenth pipeline 416 and a seventeenth pipeline 417. The sixteenth pipeline 416 and the seventeenth pipeline 417 connect the cold and heat source input side of the ground source heat pump 109 to the condenser side of the absorption chiller unit 108. The cold and heat source input side of the ground source heat pump 109 refers to the heat source or cold source required when the ground source heat pump 109 is working. A V14 switching valve 314 and a V14 switching valve 314 are connected in series on the sixteenth pipeline 416 and the seventeenth pipeline 417 respectively. When the ground source heat pump 109 is not working, the V13 switch valve 313, the V14 switch valve 314 and the V13 switch valve 313 are in the closed state. The seventh circulation pipeline includes the eighteenth pipeline 418 and the nineteenth pipeline 419. The eighteenth pipeline 418 and the nineteenth pipeline 419 connect the buried pipe group 110 to the evaporator side of the absorption chiller unit 108. A fourth circulation water pump 204 is connected in series on the eighteenth pipeline 418 to transport the water source in the buried pipe group 110 to the outside.

[0055] Based on the above embodiments, the specific implementation of the eighth circulation pipeline is as follows: The eighth circulation pipeline includes a twentieth pipeline 420 and a twenty-first pipeline 421. One end of the twentieth pipeline 420 is connected to the thirteenth pipeline 413, and the other end of the twentieth pipeline 420 is connected in parallel to the V16 three-way switch valve 316 on the sixteenth pipeline and the V18 three-way switch valve 318 on the nineteenth pipeline. One end of the twenty-first pipeline 421 is connected to the twelfth pipeline 412 and the thirteenth pipeline 413. A V20 switch valve 320 is connected in series on the section of the twenty-first pipeline 421 that connects the twelfth pipeline 412 and the thirteenth pipeline 413. The connection between the twenty-first pipeline 421 and the thirteenth pipeline 413 is located downstream of the fifth circulating water pump 205. A V21 switch valve 321 is connected in series on the thirteenth pipeline 413, and the V21 switch valve 321 is located on the twenty-first pipeline. The connection between pipeline 421 and the thirteenth pipeline 413 is between the thirteenth pipeline 413 and the twentieth pipeline 420; the other end of the twentieth pipeline 421 is connected in parallel to the V15 three-way switch valve 315 on the seventeenth pipeline and the V17 three-way switch valve 317 on the eighteenth pipeline; in practical applications, the V16 three-way switch valve 316, V18 three-way switch valve 318, V15 three-way switch valve 315 and V17 three-way switch valve 31... All 7 have three connection ports: a, b, and c. For the V15 three-way switch valve 315, ports a and b are connected in series to the seventeenth pipe 417, and port c is connected to the twenty-first pipe 421. For the V16 three-way switch valve 316, ports a and b are connected in series to the sixteenth pipe 416, and port c is connected to the twentieth pipe 420. For the V17 three-way switch valve 317, ports a and b are connected in series to the eighteenth pipe 418, and port c is connected to the twenty-first pipe 421.The a and b ports of the V18 three-way valve 318 are connected in series to the nineteenth pipe 419, and the c port is connected to the twentieth pipe 420. That is, when the a and b ports of the V16 three-way valve 316 are connected in series, water in the sixteenth pipe 416 flows through the V16 three-way valve 316 and re-enters the sixteenth pipe 416. When the c port of the V16 three-way valve 316 is connected in series with either the a or b port, the twentieth pipe 420 is connected to the sixteenth pipe 416. Similarly, when the a and b ports of the V15 three-way valve 315 are connected in series, water in the seventeenth pipe 417 flows through the V15 three-way valve 315 and re-enters the seventeenth pipe 417. When the c port of the V15 three-way valve 315 is connected in series with either the a or b port, the twentieth pipe 420 is connected to the sixteenth pipe 416. The connection between the 21st pipeline 421 and the 17th pipeline 417 is achieved when ports a and b of the V17 three-way valve 317 are connected in series. Water flowing in the 18th pipeline 418 re-enters the 18th pipeline 418 after passing through the V17 three-way valve 317. When port c of the V17 three-way valve 317 is connected in series with port a or b, the connection between the 21st pipeline 421 and the 18th pipeline 416 is achieved. When ports a and b of the V18 three-way valve 318 are connected in series, water flowing in the 19th pipeline 419 re-enters the 19th pipeline 419 after passing through the V19 three-way valve 319. When port c of the V19 three-way valve 319 is connected in series with port a or b, the connection between the 20th pipeline 420 and the 19th pipeline 419 is achieved. The ninth circulation pipeline includes the twenty-second pipeline 422 and the twenty-third pipeline 423. The twenty-second pipeline 422 connects to the seventeenth pipeline 417 and the eighteenth pipeline 418, and the twenty-third pipeline 423 connects to the sixteenth pipeline 416 and the nineteenth pipeline 419. The tenth circulation pipeline includes the twenty-fourth pipeline 424 and the twenty-fifth pipeline 425. The twenty-fourth pipeline 424 and the twenty-fifth pipeline 425 connect to the third heat exchanger 106 and the domestic hot water user terminal 107. A sixth circulation water pump 206 is connected in series on the twenty-fifth pipeline 425. The sixth circulation water pump 206 continuously draws heat from the third heat exchanger 106 to heat the water, thereby providing users with domestic hot water at a suitable temperature.

[0056] After the above subsystems are connected through their corresponding circulation pipelines, a stable supply of cooling, heating, and domestic hot water is achieved. To facilitate replacement and ensure stable system control, and to fully utilize heat at each temperature gradient stage, a first temperature sensor 501 for monitoring the outlet water temperature of the solar collector 101 is installed on the first pipeline 401; a second temperature sensor 502 for monitoring the water temperature inside the insulated water tank 102 is installed on the insulated water tank 102; a third temperature sensor 503 for monitoring the molten salt temperature is installed on the phase change heat storage device 103; a fourth temperature sensor 504 for monitoring the outlet water temperature of the phase change heat storage device is installed on the sixth pipeline 406; a fifth temperature sensor 505 for monitoring the outlet water temperature of the user terminal 111 for monitoring the cooling and heating demand is installed on the thirteenth pipeline 413; and a sixth temperature sensor 506 for monitoring the return water temperature of the second heat exchanger 105 is installed on the seventh pipeline 407. All of the above temperature sensors are electrically connected to the controller.

[0057] After integrating cooling, heating, and domestic hot water functions using the aforementioned system, to further improve the system's coupling utilization of solar and geothermal energy, and to maximize the comprehensive and effective utilization of solar and geothermal energy, this invention also provides an operation control method for a solar-coupled geothermal energy cascade utilization system, comprising the following steps:

[0058] S1. Check all relevant operating components within the system to ensure that each component is capable of normal operation.

[0059] S2. Start the controller. After the controller starts, the operator will enter the operation mode selection interface through the start screen.

[0060] S3. The operator adjusts the system's operation according to the real-time season, using either heating mode, insulation mode, cooling mode, or geothermal well storage mode. The heating mode described in this invention provides heating to users during the winter heating season. The insulation mode is used when some public office spaces temporarily do not require heating or cooling for a certain period due to reasons such as unified holidays. The cooling mode provides cooling to users during the summer heating season. The geothermal well storage mode allows excess heat to be stored in geothermal wells via underground pipe systems during transitional seasons when heating or cooling is not required.

[0061] The specific operation control logic for the aforementioned heating mode, insulation mode, cooling mode, or geothermal well storage mode includes the following:

[0062] S3.1, the operation control logic of the heating mode (such as...) Figure 2As shown (in the diagram): After the system enters the heating operation mode, the operator sets the values ​​of Ta1-Ta6 sequentially; Ta1 is the solar collector circulation temperature difference; Ta2 is the thermal storage device's start-up temperature; Ta3 is the absorption chiller / heater unit's drive temperature; Ta4 is the domestic hot water supply set temperature; Ta5 is the user-side return water set temperature; Ta6 is the thermal storage device's heat release start-up temperature. The values ​​of Ta1-Ta6 are generally given by the staff based on the local geographical environment and their work experience. Typically, Ta1-Ta4 and Ta6 can be set as follows: The values ​​are set sequentially to 3℃, 85℃, 70℃, 45℃, and 85℃; in winter, the value of Ta6 is set to 40℃, and in summer, the value of Ta6 is set to 12℃; after setting the above values, the controller controls each valve according to the set program, that is, opening the on / off valves V3, V6, and V19, opening V15 and V16 to the bc passage state; opening V17 and V18 to the ab passage state, and keeping the other valves closed. The controller synchronously operates the solar thermal collector subsystem, the solar hot water circulation subsystem, and the user and underground pipe subsystem.

[0063] When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time. T1 is the outlet water temperature of the solar thermal collector, and T2 is the hot water temperature of the insulated water tank. At the same time, the controller compares T1-T2 with Ta1 in real time. When T1-T2≥Ta1, the first and second circulating water pumps are running. When T1-T2<Ta1, the first and second circulating water pumps are stopped. The operation of the first circulating water pump 201 and the second circulating water pump 202 is controlled by comparing the difference between T1 and T2 with Ta1. The control principle is that when the temperature difference is large, the operation can transfer the heat in the solar thermal collector to the insulated water tank 103, thereby realizing heat storage.

[0064] During the operation of the solar water heating circulation subsystem, the controller monitors the values ​​of T2, T3, and T4 in real time. T3 is the molten salt temperature of the heat storage device, and T4 is the downstream water temperature of the heat storage device. Simultaneously, the controller compares T2 with T4 in real time. When T2 ≥ T4, the third circulating water pump 203 is activated. Then, T2 is compared with T2 and T3. When T2 ≥ T2, the phase change heat storage process (i.e., heat storage using a phase change heat storage device) is initiated. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve 303 is adjusted to be smaller according to the set requirements. During the phase change heat storage process, T4 is compared with T3. When T4 ≥ T3, the absorption chiller / heater unit is activated. In the heating process, valves V7 and V8 are opened, while valve V6 is closed. When T4 < Ta3, the phase change heat storage process stops. At this time, valves V1 and V2 are closed, and regulating valve V3 303 is fully opened. Then, the absorption chiller heating process resumes. When Ta2 > T2 ≥ Ta3, the system directly enters the absorption chiller heating process. When T2 < Ta3, T3 and Ta6 are compared again. When T3 ≥ Ta6, the phase change heat release process begins (releasing the heat from the phase change accumulator). At this time, valves V1 and V2 are opened, and the opening of regulating valve V3 303 is adjusted to be smaller according to the set requirements. When T3 < T2 < Ta3, the phase change heat release process resumes. When T6 is reached, the domestic hot water supply mode is directly activated. During the phase change heat release process, T4 is compared with Ta3. When T4 ≥ Ta3, the system operates the absorption chiller heating process. When T4 < Ta3, the system first stops the phase change heat release process. At this time, the V1 and V2 switching valves are closed, and the V3 regulating valve 303 is fully open. Then, the domestic hot water supply mode is activated. After the system operates the absorption chiller heating process, the domestic hot water supply mode is activated, and domestic hot water can be provided to users. When comparing T2 and Ta4, if T2 < Ta4, the comparison between T3 and Ta6 continues. When T3 ≥ Ta6, the phase change heat release process begins. At this time, valves V1 and V2 are opened, and the opening of regulating valve V3 303 is adjusted to be smaller according to the set requirements. During the phase change heat release process, T6 is compared with Ta4, where T6 is the outlet water temperature after heat exchange in the second heat exchanger 105. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the operation of the third circulating water pump 203 is stopped, and valves V3 and V6 are opened while valves V1, V2, V7, and V8 are closed. When T3 < Ta6, the operation of the third circulating water pump 203 is stopped, and valves V3 and V6 are opened while valves V1, V2, V7, and V8 are closed.

[0065] When operating the user and underground pipe subsystem, the fourth circulating water pump 204 and the fifth circulating water pump 205 are started. Simultaneously, the value of T5 is monitored in real time, and the value of Ta5 (the user-side return water temperature) is automatically adjusted according to a set program based on the ambient temperature. The system calculates whether T5 equals Ta5. If T5 = Ta5, the fourth and fifth circulating water pumps 204 and 205 continue operating. If T5 is not equal to Ta5, and if T5 > Ta5, it checks whether the ground source heat pump 109 is operating. If the ground source heat pump 109 is operating, its operating load is reduced to decrease the load. When 109 is in an inactive state, the V19 switch valve is opened, and the V11-V14 switch valves are closed simultaneously. Then, the operating load of the absorption chiller unit is reduced to lower the load. When T5 is not equal to Ta5, if T5 < Ta5, then under the current driving heat source, it is determined whether the absorption chiller unit 108 is at its maximum load. If it is at its maximum load, the ground source heat pump 109 is started. At this time, the V19 switch valve 319 is closed, and the V11-V14 switch valves are opened simultaneously. Then, the operating load of the ground source heat pump 109 is increased to increase the load. If it is not at its maximum load, the operating load of the absorption chiller unit 108 is increased to increase the load.

[0066] The operation control logic of the heat preservation mode described in S3.2 (such as...) Figure 3 As shown in the diagram: When the system enters the heat preservation mode, the operator sets the values ​​of Ta1, Ta2, Ta5, and Ta6 in sequence; after the setting is completed, the controller controls each valve according to the set program, that is, opens the V3, V4, V5, V9, V10, and V21 switching valves, while the remaining switching valves are in the closed state. Then, the controller synchronously runs the solar thermal collector subsystem, the solar hot water circulation subsystem, and the user and underground pipe subsystem.

[0067] When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time, and compares T1-T2 with Ta1 in real time. When T1-T2≥Ta1, the first circulating water pump 201 and the second circulating water pump 202 are running. When T1-T2<Ta1, the operation of the first circulating water pump 201 and the second circulating water pump 202 is stopped.

[0068] When operating the solar water heating circulation subsystem and the user and underground pipe subsystem, the controller determines whether T5 is less than Ta5. If T5 < Ta5, it continues to compare T2 with Ta5. If T2 ≥ Ta5, the third circulating water pump 203 is started. During the operation of the third circulating water pump 203, T2 is compared with Ta2. If T2 ≥ Ta2, the phase change heat storage process begins. At this time, the V1 and V2 switching valves open, and the opening of the V3 regulating valve 303 is adjusted to be smaller according to the set requirements. During the phase change heat storage process, T4 is compared with... When comparing T4 and Ta5, if T4 ≥ Ta5, then the fifth circulating water pump 205 operates alone; if T4 < Ta5, the phase change heat storage process stops. At this time, the V1 and V2 switching valves are closed, while the V3 regulating valve 303 is fully open. Then, the fifth circulating water pump 205 operates alone again. When comparing T2 and Ta2, if T2 < Ta2, then the fifth circulating water pump operates alone. When comparing T2 and Ta5, if T2 < Ta5, then T3 and Ta6 are compared. If T3 ≥ Ta6, then the third circulating water pump 203 operates. Upon entering the phase change heat release process, valves V1 and V2 open, and the opening of regulating valve V3 is adjusted to be smaller according to the set requirements. During the phase change heat release process, the comparison between T4 and Ta5 continues. When T4 ≥ Ta5, the heating process of ground source heat pump 109 begins, and the fifth circulating water pump 205 operates independently. When T4 < Ta5, ground source heat pump 109, the fourth circulating pump 204, and the fifth circulating pump 205 are started, valves V11-V14 are opened, regulating valve V3 is fully opened, and valves V1, V2, V9, and V10 are closed. The third circulating water pump 203; when comparing T3 and Ta6, if T3 < Ta6, the ground source heat pump heating process is initiated; when the fifth circulating water pump 205 is turned on, the second heat exchanger 105 enters the heat exchange working state; when the system determines whether T5 is less than Ta5, if T5 ≥ Ta5, the system operation is stopped. At this time, the V9 and V10 switching valves are opened, the V3 regulating valve 303 is at its maximum opening, and the V1, V2, and V11-V14 switching valves are closed, stopping the operation of the third circulating water pump 203, the fourth circulating water pump 204, and the fifth circulating water pump 205;

[0069] The operating control logic of the cooling mode described in S3.3 is as follows: When the system enters the cooling operation mode, the operator sets the values ​​of Ta1-Ta6 in sequence; after the above values ​​are set, the controller controls each valve according to the set program, that is, opens the V3, V6 and V19 switching valves, opens V15 and V16 to the ab passage state, opens V17 and V18 to the bc passage state, and the remaining switching valves are in the closed state; the controller simultaneously operates the solar thermal collector subsystem, the solar hot water circulation subsystem and the user and underground pipe subsystem;

[0070] When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time; at the same time, the controller compares T1-T2 with Ta1 in real time; when T1-T2≥Ta1, the first and second circulating water pumps are running; when T1-T2<Ta1, the first and second circulating water pumps are stopped.

[0071] During the operation of the solar water heating circulation subsystem, the controller monitors the values ​​of T2, T3, and T4 in real time, and simultaneously compares T2 with Ta4. When T2 ≥ Ta4, the third circulating water pump 203 is activated. Then, T2 is compared with Ta2 and Ta3. When T2 ≥ Ta2, the phase change heat storage process is initiated. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve 303 is adjusted to be smaller according to the set requirements. During the phase change heat storage process, T4 is compared with Ta3. When T4 ≥ Ta3, the cooling process of the absorption chiller unit 108 is initiated. At this time, the V7 and V8 switching valves are opened. Simultaneously, close the V6 switch valve; when T4 < Ta3, stop the phase change heat storage process. At this time, close the V1 and V2 switch valves, and fully open the V3 regulating valve 303. Then, enter the absorption chiller cooling process. When Ta2 > T2 ≥ Ta3, the system directly enters the absorption chiller cooling process. When T2 < Ta3, compare T3 and Ta6 again. When T3 ≥ Ta6, enter the phase change heat release process. At this time, open the V1 and V2 switch valves, and adjust the opening of the V3 regulating valve 303 to be smaller according to the set requirements. When T3 < Ta6, directly start the domestic hot water supply mode. In the phase change heat release process, T4 is compared with Ta3. When T4 ≥ Ta3, the system operates the absorption chiller cooling process. When T4 < Ta3, the system first stops the phase change heat release process. At this time, the V1 and V2 switching valves are closed, and the V3 regulating valve 303 is fully open. Then, the domestic hot water supply mode is activated. After the system operates the absorption chiller cooling process, the domestic hot water supply mode is activated, and domestic hot water can be provided to users. When comparing T2 with Ta4, if T2 < Ta4, the comparison between T3 and Ta6 continues. When T4 < Ta3, the comparison continues. When T6 ≥ Ta6, the third circulating water pump 203 is turned on, and then the phase change heat release process begins. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve 303 is adjusted to be smaller according to the set requirements. In the phase change heat release process, T6 and Ta4 are compared. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the operation of the third circulating water pump is stopped, and at the same time, the V3 and V6 valves are opened and the V1, V2, V7 and V8 valves are closed. When T3 < Ta6, the operation of the third circulating water pump is stopped, and at the same time, the V3 and V6 valves are opened and the V1, V2, V7 and V8 valves are closed.

[0072] When operating the user and underground pipe subsystems, the fourth and fifth circulating water pumps are started. Simultaneously, the value of T5 is monitored in real time, and the value of Ta5 (the user-side return water temperature) is automatically adjusted according to a set program based on the ambient temperature. The system calculates whether T5 equals Ta5. If T5 = Ta5, the fourth and fifth circulating water pumps continue operating. If T5 is not equal to Ta5, and if T5 > Ta5, it checks whether the ground source heat pump is running. If the ground source heat pump is running, the operating load is reduced to lower the load. When not in operation, open valve V19 and close valves V11-V14 simultaneously. Then, reduce the operating load of the absorption chiller unit to lower the load. When T5 is not equal to Ta5, if T5 < Ta5, determine whether the absorption chiller unit is at its maximum load under the current driving heat source. If it is at its maximum load, start the ground source heat pump. At this time, close valve V19 and open valves V11-V14 simultaneously. Then, increase the operating load of the ground source heat pump to increase the load. If it is not at its maximum load, increase the operating load of the absorption chiller unit to increase the load.

[0073] When the absorption heat and cooling unit 108 is running in the cooling mode, the underground pipe group 110 provides a large amount of cooling water to the absorption heat and cooling unit 108. After the cooling water flows out of the absorption heat and cooling unit 108, its temperature is maintained at about 35°C. At this time, this part of the heat can be stored in the geothermal well to balance the heat loss in winter.

[0074] The geothermal well heat storage mode operation control logic described in S3.4 is as follows: When the system enters the geothermal well heat storage operation mode, the operator sets Ta1, Ta2, Ta4, Ta6, and Ta7 in sequence; Ta7 is the operating start temperature of the second heat exchanger 105; after setting the above values, the controller controls each valve according to the set program, that is, opens the V3, V6, V9, V10, and V20 switch valves, opens V15, V16 or V17, and V18 to the ac passage state, and the remaining switch valves are in the closed state. The controller synchronously operates the solar thermal collector subsystem, the solar hot water circulation subsystem, and the user and buried pipe subsystem.

[0075] When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time; at the same time, the controller compares T1-T2 with Ta1 in real time; when T1-T2≥Ta1, the first circulating water pump 201 and the second circulating water pump 202 are running; when T1-T2<Ta1, the operation of the first circulating water pump 201 and the second circulating water pump 202 is stopped.

[0076] During the operation of the solar water heating circulation subsystem and the underground pipe subsystem, the controller monitors the values ​​of T2, T3, T4, and T6 in real time. Simultaneously, the controller compares T2 with Ta4 in real time. When T2 ≥ Ta4, the third circulating water pump 203 is activated. Then, T2 is compared with Ta2 and Ta7. When T2 ≥ Ta2, the phase change heat storage process begins. At this time, the V1 and V2 switching valves open, and the opening of the V3 regulating valve 303 is adjusted to decrease according to the set requirements. During the phase change heat storage process, T4 is compared with Ta7. When T4 ≥ Ta7, the second heat exchanger 105 enters the heat exchange mode. In the second heat exchanger mode, the second heat exchanger 105 performs heat exchange. When V5 switch valve is open and V6 switch valve is closed, the phase change heat storage process stops when T4 < Ta7. At this time, V1 and V2 switch valves are closed, and V3 regulating valve is fully opened. Then, the system enters the heat exchange mode of the second heat exchanger 105. When Ta2 > T2 ≥ Ta7, the system directly enters the heat exchange mode of the second heat exchanger. When T2 < Ta7, T3 and Ta6 are compared again. When T3 ≥ Ta6, the phase change heat release process begins. At this time, V1 and V2 switch valves are opened, and the opening of V3 regulating valve 303 is adjusted to be smaller according to the set requirements. When T3 < Ta6, the domestic hot water supply mode is directly started. During the phase change heat release process, T4 and Ta7 are compared... The comparison process is as follows: When T4 ≥ Ta7, the system operates in the second heat exchanger heat exchange mode; when T4 < Ta7, the system first stops the phase change heat release process. At this time, the V1 and V2 switching valves are closed, and the V3 regulating valve 303 is fully open. Then, the domestic hot water supply mode is activated. After the system enters the second heat exchanger heat exchange mode, T6 is compared with Ta4. When T6 ≥ Ta4, the domestic hot water supply mode is directly activated. When T6 < Ta4, the operation of the fourth circulating water pump 204 is stopped. At this time, the V6 switching valve 306 is opened, and the V4 and V5 switching valves are closed. Then, the domestic hot water supply mode is activated again. When comparing T2 with Ta4, if T2 < Ta4, the process continues... A comparison is made between T3 and Ta6. When T3 ≥ Ta6, the third circulating water pump 203 is started, and then the phase change heat release process begins. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve 303 is adjusted to be smaller according to the set requirements. During the phase change heat release process, a comparison is made between T6 and Ta4. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the operation of the third circulating water pump 203 is stopped, and at the same time, the V3 and V6 valves are opened, and the V1, V2, V4 and V5 valves are closed. When T3 < Ta6, the operation of the third circulating water pump 203 is stopped, and at the same time, the V3 and V6 valves are opened, and the V1, V2, V4 and V5 valves are closed.

[0077] In the geothermal well heat storage mode, the heat stored in the solar collector can be exchanged with the buried pipe group 110 through the second heat exchanger 105 under certain conditions, so that the heat is stored in the soil and geothermal balance is achieved, so that the soil can provide an effective and stable heat source for the ground source heat pump 109 in winter.

[0078] Except for the technical features described in the specification, all other technologies are known to those skilled in the art.

[0079] The preferred embodiments and examples of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments and examples. For those skilled in the art, several improvements and modifications can be made without departing from the concept of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A solar-coupled geothermal energy cascade utilization system, characterized in that, The system includes a solar thermal collector subsystem, a solar hot water circulation subsystem, a user and underground pipe subsystem, and a controller. The solar thermal collector subsystem includes a solar collector device, a first heat exchanger, and an insulated water tank. The solar hot water circulation subsystem includes a phase change heat storage device, a second heat exchanger, a third heat exchanger, a domestic hot water user terminal, an absorption chiller / heater unit, and the insulated water tank. The user and underground pipe system includes a ground source heat pump, underground pipe assemblies, and a user terminal for heating and cooling needs. The solar thermal collector device, the first heat exchanger, and the insulated water tank exchange heat through a first circulation pipeline. The insulated water tank, the phase change heat storage device, the second heat exchanger, and the third heat exchanger exchange heat through a second circulation pipeline. The heat source drive side of the absorption chiller / heater unit connects to the second circulation pipeline through a third circulation pipeline. The second heat exchanger exchanges heat with the user end requiring hot and cold water through the fourth circulation pipeline. The user side of the ground source heat pump is connected to the fourth circulation pipeline through the fifth circulation pipeline. The condenser side of the absorption chiller unit is connected to the cold and heat source input side of the ground source heat pump through the sixth circulation pipeline. The evaporator side of the absorption chiller unit is connected to the buried pipe group through the seventh circulation pipeline. The fourth circulation pipeline is connected to the sixth and seventh circulation pipelines through the eighth circulation pipeline. The ninth circulation pipeline connects the sixth and seventh circulation pipelines. The third heat exchanger is connected to the domestic hot water user end through the tenth circulation pipeline. The controller is used to control the operation of the absorption chiller unit, the ground source heat pump, the tenth circulation pipeline, and the first to eighth circulation pipelines.

2. The energy cascade utilization system of solar coupled geothermal energy according to claim 1, characterized in that, The first circulation pipeline includes a first pipeline, a second pipeline, a third pipeline, and a fourth pipeline. The first and second pipelines connect the solar thermal collector to the first heat exchanger. A first circulating water pump is connected in series on the second pipeline. The third and fourth pipelines connect the first heat exchanger to the insulated water tank. A second circulating water pump is connected in series on the fourth pipeline.

3. The energy cascade utilization system of solar coupled geothermal energy according to claim 2, characterized in that, The second circulation pipeline includes a fifth pipeline, a sixth pipeline, a seventh pipeline, an eighth pipeline, and a ninth pipeline. The fifth pipeline connects the insulated water tank and the phase change heat storage device. The sixth pipeline connects the phase change heat storage device and the second heat exchanger. The seventh pipeline connects the second heat exchanger and the third heat exchanger. The eighth pipeline connects the third heat exchanger and the insulated water tank. The ninth pipeline is connected in series between the fifth and sixth pipelines. A V3 regulating valve is connected in series on the ninth pipeline. A third circulating water pump and a V1 switching valve are connected in series on the fifth pipeline, with the V1 switching valve located downstream of the connection between the ninth and fifth pipelines. A V2 switching valve and a V4 switching valve are connected in series on the sixth pipeline, with the V2 and V4 switching valves located upstream and downstream of the connection between the ninth and sixth pipelines, respectively. A V5 switching valve is connected in series on the seventh pipeline.

4. The energy cascade utilization system of solar energy coupled with geothermal energy according to claim 3, characterized in that, The third circulation pipeline includes a tenth pipeline and an eleventh pipeline. The heat source drive side of the absorption chiller unit is connected to the sixth pipeline through the tenth pipeline, and the connection point between the tenth pipeline and the sixth pipeline is located upstream of the V4 switch valve. The heat source drive side of the absorption chiller unit is connected to the sixth and seventh pipelines through the eleventh pipeline. The connection point between the eleventh pipeline and the sixth pipeline is located upstream of the V4 switch valve, and the connection point between the eleventh pipeline and the seventh pipeline is located upstream of the V5 switch valve. A V6 switch valve is connected in series on the eleventh pipeline section located between the sixth and seventh pipelines. A V7 switch valve and a V8 switch valve are connected in series on the tenth pipeline and the eleventh pipeline, respectively.

5. The energy cascade utilization system of solar coupled geothermal energy according to claim 4, characterized in that, The fourth circulation pipeline includes the twelfth and thirteenth pipelines, which connect the second heat exchanger to the user side with heating and cooling requirements. A V10 switch valve is connected in series on the twelfth pipeline, and a V9 switch valve and a fifth circulating water pump are connected in series on the thirteenth pipeline. The fifth circulation pipeline includes the fourteenth and fifteenth pipelines. The user side of the ground source heat pump connects to the twelfth and thirteenth pipelines through the fourteenth pipeline. The connection point between the fourteenth and twelfth pipelines is located downstream of the V10 switch valve, and the connection point between the fourteenth and thirteenth pipelines is located upstream of the V9 switch valve. A V19 switch valve is connected in series on the section of the fourteenth pipeline located between the twelfth and thirteenth pipelines. A V11 switch valve and a V12 switch valve are connected in series on the fourteenth and fifteenth pipelines, respectively.

6. The energy cascade utilization system of solar coupled geothermal energy according to claim 5, characterized in that, The sixth circulation pipeline includes the sixteenth and seventeenth pipelines, which connect the cold and heat source input side of the ground source heat pump to the condenser side of the absorption chiller unit. A V14 switch valve and a V13 switch valve are connected in series on the sixteenth and seventeenth pipelines, respectively. The seventh circulation pipeline includes the eighteenth and nineteenth pipelines, which connect the buried pipe assembly to the evaporator side of the absorption chiller unit. A fourth circulation water pump is connected in series on the eighteenth pipeline.

7. The energy cascade utilization system of solar energy coupled with geothermal energy according to claim 6, characterized in that, The eighth circulation pipeline includes the twentieth and twentieth pipelines. One end of the twentieth pipeline is connected to the thirteenth pipeline, and the other end of the twentieth pipeline is connected in parallel to the V16 three-way valve on the sixteenth pipeline and the V18 three-way valve on the nineteenth pipeline. One end of the twentieth pipeline connects the twelfth and thirteenth pipelines, and a V20 valve is connected in series on the section of the twentieth pipeline connecting the twelfth and thirteenth pipelines. The connection between the twentieth and thirteenth pipelines is located downstream of the fifth circulating water pump. A V21 valve is connected in series on the thirteenth pipeline, and the V21 valve is located on the twentieth pipeline. The connection between the thirteenth and twentieth pipelines is as follows: The other end of the twentieth pipeline is connected in parallel to the V15 three-way valve on the seventeenth pipeline and the V17 three-way valve on the eighteenth pipeline; The ninth circulation pipeline includes the twentieth and twentieth pipelines, with the twentieth pipeline connecting the seventeenth and eighteenth pipelines and the twentieth pipeline connecting the sixteenth and nineteenth pipelines; The tenth circulation pipeline includes the twentieth and twentieth pipelines, with the twentieth and twentieth pipelines connecting the third heat exchanger and the domestic hot water user end, and a sixth circulation pump is connected in series on the twentieth pipeline.

8. A solar-coupled geothermal energy cascade utilization system according to claim 7, characterized in that, in A first temperature sensor for monitoring the outlet water temperature of the solar thermal collector is installed on the first pipeline; a second temperature sensor for monitoring the water temperature inside the insulated water tank is installed on the insulated water tank; a third temperature sensor for monitoring the molten salt temperature is installed on the phase change heat storage device; a fourth temperature sensor for monitoring the outlet water temperature of the phase change heat storage device is installed on the sixth pipeline; a fifth temperature sensor for monitoring the outlet water temperature at the user end of the heating and cooling demand is installed on the thirteenth pipeline; and a sixth temperature sensor for monitoring the return water temperature of the second heat exchanger is installed on the seventh pipeline. The solar thermal collector is a solar collector, the phase change heat storage device is a phase change heat storage device, the absorption chiller is an absorption heat pump, and the first to third heat exchangers are all plate heat exchangers.

9. A method for operating and controlling a solar-coupled geothermal energy cascade utilization system according to claim 8, characterized in that, Includes the following steps: S1. Check all relevant operating components within the system to ensure that each component is capable of normal operation. S2. Start the controller. After the controller starts, the operator will enter the operation mode selection interface through the start screen. S3. Operators can adjust the system's operation mode (heating, insulation, cooling, or geothermal well storage) based on the real-time season.

10. The operation control method for a solar-coupled geothermal energy cascade utilization system according to claim 9, characterized in that, S3.1 The operation control logic of the heating mode is as follows: When the system enters the heating operation mode, the operator sets the values ​​of Ta1-Ta6 in sequence; Ta1 is the solar collector circulation temperature difference; Ta2 is the start-up temperature of the heat storage device. Ta3 is the driving temperature of the absorption chiller / heater unit; Ta4 is the set temperature for domestic hot water supply; Ta5 is the set temperature for user-side return water; Ta6 is the start-up temperature for the heat storage device. After setting the above values, the controller controls each valve according to the set program, that is, opening the V3, V6, and V19 switching valves; opening V15 and V16 to the bc passage state; opening V17 and V18 to the ab passage state. The controller simultaneously operates the solar collector subsystem, the solar hot water circulation subsystem, and the user and underground pipe subsystem. The a and b ports of the V15 three-way switching valve are connected in series to the seventeenth pipe, and the c port is connected to the twenty-first pipe. The a and b ports of the V16 three-way switching valve are connected in series to the sixteenth pipe, and the c port is connected to the twentieth pipe. The a and b ports of the V17 three-way switching valve are connected in series to the eighteenth pipe, and the c port is connected to the twenty-first pipe. The a and b ports of the V18 three-way switching valve are connected in series to the nineteenth pipe, and the c port is connected to the twentieth pipe. When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time. T1 is the outlet water temperature of the solar thermal collector; T2 is the hot water temperature of the insulated water tank. At the same time, the controller compares T1-T2 with Ta1 in real time. When T1-T2≥Ta1, the first and second circulating water pumps are running; when T1-T2<Ta1, the first and second circulating water pumps are stopped. During the operation of the solar water heating circulation subsystem, the controller monitors the values ​​of T2, T3, and T4 in real time. T3 is the molten salt temperature of the heat storage device, and T4 is the downstream water temperature of the heat storage device. Simultaneously, the controller compares T2 with T4 in real time. When T2 ≥ T4, the third circulating water pump starts. Then, T2 is compared with T2 and T3. When T2 ≥ T2, the phase change heat storage process begins. At this time, the V1 and V2 switching valves open, and the opening of the V3 regulating valve is adjusted to decrease according to the set requirements. During the phase change heat storage process, T4 is compared with T3. When T4 ≥ T3, the heating process of the absorption chiller / heater unit begins. Open valves V7 and V8, and simultaneously close valve V6. When T4 < Ta3, stop the phase change heat storage process. At this time, close valves V1 and V2, and fully open valve V3. Then, enter the absorption chiller heating process. When Ta2 > T2 ≥ Ta3, the system directly enters the absorption chiller heating process. When T2 < Ta3, compare T3 and Ta6 again. When T3 ≥ Ta6, enter the phase change heat release process. At this time, valves V1 and V2 are opened, and the opening of valve V3 is adjusted to be smaller according to the set requirements. When T3 < Ta6, directly start the domestic hot water supply mode. During the phase change heat release process, T4 is compared with Ta3. When T4 ≥ Ta3, the system operates the absorption chiller heating process. When T4 < Ta3, the system first stops the phase change heat release process. At this time, the V1 and V2 switching valves are closed, and the V3 regulating valve is fully open. Then, the domestic hot water supply mode is started. After the system operates the absorption chiller heating process, the system starts the domestic hot water supply mode. Under the domestic hot water supply mode, domestic hot water can be provided to users. When T2 < Ta4, the comparison between T3 and Ta6 continues. When T3 ≥ Ta6, the phase change heat release process begins. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve is adjusted to be smaller according to the set requirements. During the phase change heat release process, the comparison between T6 and Ta4 is performed. T6 is the outlet water temperature after heat exchange in the second heat exchanger. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the operation of the third circulating water pump is stopped, and the V3 and V6 valves are opened while the V1, V2, V7, and V8 valves are closed. When T3 < Ta6, the operation of the third circulating water pump is stopped, and the V3 and V6 valves are opened while the V1, V2, V7, and V8 valves are closed. When operating the user and underground pipe subsystems, the fourth and fifth circulating water pumps are started. Simultaneously, the value of T5 is monitored in real time, and the value of Ta5 (the user-side return water temperature) is automatically adjusted according to a set program based on the ambient temperature. The system calculates whether T5 equals Ta5. If T5 = Ta5, the fourth and fifth circulating water pumps continue operating. If T5 is not equal to Ta5, and if T5 > Ta5, it checks whether the ground source heat pump is running. If the ground source heat pump is running, the operating load is reduced to lower the load. When not in operation, open valve V19 and close valves V11-V14 simultaneously. Then, reduce the operating load of the absorption chiller unit to lower the load. When T5 is not equal to Ta5, if T5 < Ta5, determine whether the absorption chiller unit is at its maximum load under the current driving heat source. If it is at its maximum load, start the ground source heat pump. At this time, close valve V19 and open valves V11-V14 simultaneously. Then, increase the operating load of the ground source heat pump to increase the load. If it is not at its maximum load, increase the operating load of the absorption chiller unit to increase the load. The operating control logic of the heat preservation mode described in S3.2 is as follows: When the system enters the heat preservation mode, the operator sets the values ​​of Ta1, Ta2, Ta5, and Ta6 in sequence; after the setting is completed, the controller controls each valve according to the set program, that is, opens the on / off valves V3, V4, V5, V9, V10, and V21. Then, the controller synchronously operates the solar thermal collector subsystem, the solar hot water circulation subsystem, and the user and underground pipe subsystem. When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time, and compares T1-T2 with Ta1 in real time; when T1-T2≥Ta1, the first and second circulating water pumps are activated. When T1-T2 < Ta1, stop the operation of the first and second circulating water pumps; When operating the solar water heating circulation subsystem and the user and underground pipe subsystem, the controller determines whether T5 is less than Ta5. If T5 < Ta5, it continues to compare T2 with Ta5. If T2 ≥ Ta5, the third circulating water pump is started. During the operation of the third circulating water pump, T2 is compared with Ta2. If T2 ≥ Ta2, the phase change heat storage process begins. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve is adjusted to be smaller according to the set requirements. During the phase change heat storage process, T4 is compared with Ta5. If T4 ≥ Ta5, the fifth circulating water pump runs alone. If T4 < Ta5, the phase change heat storage process stops. At this time, the V1 and V2 switching valves are closed, and the V3 regulating valve is fully opened. Then, the fifth circulating water pump runs alone. When comparing T2 with Ta2, if T2 < Ta5, the process continues. If T2 < Ta5, then T3 is compared with Ta6. If T3 ≥ Ta6, then the third circulating water pump is run. Then, the phase change heat release process begins. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve is adjusted to be smaller according to the set requirements. During the phase change heat release process, the comparison between T4 and Ta5 continues. If T4 ≥ Ta5, then the ground source heat pump heating process begins. At this time, the fifth circulating water pump runs alone. If T4 < Ta5, the ground source heat pump, the fourth circulating pump, and the fifth circulating pump are started. The V11-V14 switching valves are opened, the V3 regulating valve is fully opened, and the V1, V2, V9, V10 switching valves and the third circulating water pump are closed. If T3 < Ta6, then the ground source heat pump heating process begins. When the fifth circulating water pump is turned on, the second heat exchanger enters the heat exchange working state. When the system judges whether T5 is less than Ta5, if T5 ≥ Ta5, the system stops running. At this time, the V9 and V10 switch valves are opened, the V3 regulating valve opening is at its maximum, and the V1, V2, V11-V14 switch valves are closed, stopping the operation of the third, fourth and fifth circulating water pumps. The operation control logic of the cooling mode described in S3.3 is as follows: When the system enters the cooling operation mode, the operator sets the values ​​of Ta1-Ta6 in sequence; after the above values ​​are set, the controller controls each valve according to the set program, that is, opens the on / off valves V3, V6 and V19, opens V15 and V16 to the ab passage state, and opens V17 and V18 to the bc passage state; the controller simultaneously operates the solar thermal collector subsystem, the solar hot water circulation subsystem and the user and underground pipe subsystem. When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time; at the same time, the controller compares T1-T2 with Ta1 in real time; when T1-T2≥Ta1, the first and second circulating water pumps are running; when T1-T2<Ta1, the first and second circulating water pumps are stopped. During the operation of the solar water heating circulation subsystem, the controller monitors the values ​​of T2, T3, and T4 in real time, and simultaneously compares T2 with Ta4. When T2 ≥ Ta4, the third circulating water pump is activated. Then, T2 is compared with Ta2 and Ta3. When T2 ≥ Ta2, the phase change heat storage process begins. At this time, valves V1 and V2 are opened, and the opening of regulating valve V3 is adjusted to be smaller according to the set requirements. During the phase change heat storage process, T4 is compared with Ta3. When T4 ≥ Ta3, the absorption chiller cooling process begins. At this time, valves V7 and V8 are opened. When T4 < Ta3, the phase change heat storage process is stopped. At this time, the V1 and V2 switch valves are closed, and the V3 regulating valve is fully opened. Then, the absorption chiller cooling process is started. When Ta2 > T2 ≥ Ta3, the system directly enters the absorption chiller cooling process. When T2 < Ta3, T3 and Ta6 are compared again. When T3 ≥ Ta6, the phase change heat release process is started. At this time, the V1 and V2 switch valves are opened, and the opening of the V3 regulating valve is adjusted to be smaller according to the set requirements. When T3 < Ta6, the domestic hot water supply mode is directly started. During the phase change heat release process, T4 is compared with Ta3. When T4 ≥ Ta3, the system operates the absorption chiller cooling process. When T4 < Ta3, the system first stops the phase change heat release process. At this time, the V1 and V2 switching valves are closed, and the V3 regulating valve is fully open. Then, the domestic hot water supply mode is started. After the system operates the absorption chiller cooling process, the system starts the domestic hot water supply mode. Under the domestic hot water supply mode, domestic hot water can be provided to users. When T2 < Ta4, the comparison between T3 and Ta6 continues. When T3 ≥ Ta6, the third circulating water pump is started, and the phase change heat release process begins. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve is adjusted to be smaller according to the set requirements. During the phase change heat release process, the comparison between T6 and Ta4 is performed. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the operation of the third circulating water pump is stopped, and the V3 and V6 valves are opened while the V1, V2, V7, and V8 valves are closed. When T3 < Ta6, the operation of the third circulating water pump is stopped, and the V3 and V6 valves are opened while the V1, V2, V7, and V8 valves are closed. When operating the user and underground pipe subsystems, the fourth and fifth circulating water pumps are started. Simultaneously, the value of T5 is monitored in real time, and the value of Ta5 (the user-side return water temperature) is automatically adjusted according to a set program based on the ambient temperature. The system calculates whether T5 equals Ta5. If T5 = Ta5, the fourth and fifth circulating water pumps continue operating. If T5 is not equal to Ta5, and if T5 > Ta5, it checks whether the ground source heat pump is running. If the ground source heat pump is running, the operating load is reduced to lower the load. When not in operation, open valve V19 and close valves V11-V14 simultaneously. Then, reduce the operating load of the absorption chiller unit to lower the load. When T5 is not equal to Ta5, if T5 < Ta5, determine whether the absorption chiller unit is at its maximum load under the current driving heat source. If it is at its maximum load, start the ground source heat pump. At this time, close valve V19 and open valves V11-V14 simultaneously. Then, increase the operating load of the ground source heat pump to increase the load. If it is not at its maximum load, increase the operating load of the absorption chiller unit to increase the load. The geothermal well heat storage mode operation control logic described in S3.4 is as follows: When the system enters the geothermal well heat storage operation mode, the operator sets Ta1, Ta2, Ta4, Ta6, and Ta7 in sequence; Ta7 is the start-up temperature of the second heat exchanger; after setting the above values, the controller controls each valve according to the set program, that is, opens the on / off valves V3, V6, V9, V10, and V20, and opens V15, V16 or V17, V18 to the ac passage state. The controller simultaneously operates the solar thermal collector subsystem, the solar hot water circulation subsystem, and the user and buried pipe subsystem. When the solar thermal collector subsystem is running, the controller monitors the values ​​of T1 and T2 in real time; at the same time, the controller compares T1-T2 with Ta1 in real time; when T1-T2≥Ta1, the first circulating water pump and the second circulating water pump are activated. When T1-T2 < Ta1, stop the operation of the first and second circulating water pumps; During the operation of the solar water heating circulation subsystem and the underground pipe subsystem, the controller monitors the values ​​of T2, T3, T4, and T6 in real time. Simultaneously, the controller compares T2 with Ta4 in real time. When T2 ≥ Ta4, the third circulating water pump starts. Then, T2 is compared with Ta2 and Ta7. When T2 ≥ Ta2, the phase change heat storage process begins. At this time, the V1 and V2 switching valves open, and the opening of the V3 regulating valve is adjusted to decrease according to the set requirements. During the phase change heat storage process, T4 is compared with Ta7. When T4 ≥ Ta7, the second heat exchanger heat exchange mode is entered. In the second heat exchanger heat exchange mode, the second heat exchanger... During heat exchange, valves V4 and V5 are opened, and valve V6 is closed. When T4 < Ta7, the phase change heat storage process stops. At this time, valves V1 and V2 are closed, and valve V3 is fully opened. Then, the system enters the second heat exchanger mode. When Ta2 > T2 ≥ Ta7, the system directly enters the second heat exchanger mode. When T2 < Ta7, T3 and Ta6 are compared again. When T3 ≥ Ta6, the system enters the phase change heat release process. At this time, valves V1 and V2 are opened, and the opening of valve V3 is adjusted to be smaller according to the set requirements. When T3 < Ta6, the domestic hot water supply mode is directly started. During the phase change heat release process, T4 is compared with Ta7. When T4 ≥ Ta7, the system operates in the second heat exchanger heat exchange mode. When T4 < Ta7, the system first stops the phase change heat release process. At this time, the V1 and V2 switching valves are closed, and the V3 regulating valve is fully open. Then, the domestic hot water supply mode is started. After the system enters the second heat exchanger heat exchange mode, T6 is compared with Ta4. When T6 ≥ Ta4, the domestic hot water supply mode is directly started. When T6 < Ta4, the operation of the fourth circulating water pump is stopped. At this time, the V6 switching valve is opened, and the V4 and V5 switching valves are closed. Then, the domestic hot water supply mode is started again. When T2 < Ta4... The comparison between T3 and Ta6 continues. When T3 ≥ Ta6, the third circulating water pump is started, and then the phase change heat release process begins. At this time, the V1 and V2 switching valves are opened, and the opening of the V3 regulating valve is adjusted to be smaller according to the set requirements. In the phase change heat release process, the comparison between T6 and Ta4 is performed. When T6 ≥ Ta4, the system starts the domestic hot water supply mode. When T6 < Ta4, the operation of the third circulating water pump is stopped, and at the same time, the V3 and V6 valves are opened, and the V1, V2, V4 and V5 valves are closed. When T3 < Ta6, the operation of the third circulating water pump is stopped, and at the same time, the V3 and V6 valves are opened, and the V1, V2, V7 and V8 valves are closed.

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