A cross-seasonal heating system

Abstract

The application discloses a kind of cross-season heat supply systems, including photovoltaic photo-thermal heat collecting unit, underground heat storage unit and external heat supply interface, and the heat collecting side of photovoltaic photo-thermal heat collecting unit is connected with underground heat storage unit and is used as input heat source, and underground heat storage unit and external heat supply interface are connected and used for output heat;Its characterized in that, the power generation end of the photovoltaic photo-thermal heat collecting unit is connected with energy storage battery and is used as the power supply of system power component, and water source heat pump unit is further connected and arranged between underground heat storage unit and external heat supply interface through regulation and control pipeline system.This application has the advantages of low heat loss, fast heat response speed of heat storage temperature rise and heat release, higher energy utilization efficiency and the like.

Description

Technical Field

[0001] This invention relates to the field of renewable energy utilization and HVAC engineering technology, specifically to a cross-seasonal heating system utilizing solar and geothermal energy. Background Technology

[0002] Building heating is a core area for energy consumption and carbon emission control. Traditional coal-fired and gas-fired centralized heating models suffer from high carbon emission intensity, heavy reliance on fossil fuels, low energy efficiency, and localized environmental pollution. Clean and renewable energy heating, with solar energy as its core, has become the core technological path for decarbonization transformation in the building heating sector.

[0003] The core bottleneck of solar heating lies in its inherent intermittency, volatility, and seasonal supply-demand mismatch: solar resources are abundant in summer, but building heating demand is extremely low; conversely, peak heating demand in winter faces insufficient solar resources and poor irradiance stability. Cross-seasonal thermal storage technology is key to resolving this supply-demand contradiction and achieving stable year-round solar heating. Currently, cross-seasonal thermal storage technologies mainly fall into two categories: water tank storage and buried pipe storage in rock and soil. Both technologies have inherent shortcomings that cannot be solved by a single solution. Existing applications often implement them as independent thermal storage schemes, failing to form a deeply coupled system design that allows for complementary advantages. Technical bottlenecks still exist in practical engineering applications. Firstly, existing cross-seasonal water tank thermal storage systems suffer from deficiencies in thermal storage efficiency, thermal response speed, and thermal energy utilization. Traditional single-unit large-volume water tank thermal storage inherently suffers from high thermal inertia, resulting in slow temperature rise and long charging cycles in the early stages of the non-heating season. During the heating season, the thermal response speed is slow, failing to quickly match the dynamic changes in building heating load. Furthermore, while the water temperature may be sufficient for direct supply in the early stages of the heating season, it drops rapidly in the middle and later stages as heat is continuously released, drastically reducing the utilization efficiency of stored thermal energy. Simultaneously, the natural temperature stratification of the water body is easily disrupted during the charging and releasing process, leading to the mixing of high-grade and low-grade thermal energy, further reducing thermal energy utilization efficiency.

[0004] Secondly, existing cross-seasonal thermal storage systems lack sufficient long-term heat loss control capabilities. The cross-seasonal availability of water tank thermal storage is greatly affected by radial heat loss. Existing technologies mostly rely on adding insulation layers to reduce heat loss, which not only makes underground construction difficult and costly, but also makes the insulation layers prone to aging and damage when buried underground for a long time, resulting in a gradual decline in the heat loss control effect year by year. On the other hand, buried pipe thermal storage technology in rock and soil generally suffers from low thermal storage density, large footprint, high cost of high-grade thermal energy storage, and large fluctuations in winter heat extraction temperature, making it difficult to meet the stable load requirements of building heating when used alone. In existing technologies, water tank thermal storage and buried pipe thermal storage are mostly used as independent thermal storage solutions. There is no system design that deeply couples the two, and it is impossible to solve the core pain points of the two solutions through technological complementarity: it is impossible to use the buried pipes laid around the water tank to build a thermal barrier with the surplus low-grade solar energy in summer to fundamentally block the radial heat loss from the water tank to the surrounding soil and rock; it is also impossible to achieve graded storage and tiered utilization of thermal energy through the synergy of high-grade thermal storage in the water tank and low-grade thermal storage in the buried pipe. As a result, the availability rate and energy utilization efficiency of cross-seasonal thermal storage have always been difficult to break through the existing bottlenecks in the industry.

[0005] Third, existing photovoltaic-thermal (PVT) coupled systems suffer from low energy cascade utilization efficiency and poor system self-consistency. Many existing PVT systems suffer from insufficient synergy between photovoltaic conversion and solar thermal utilization. Either they prioritize photovoltaic power generation, leaving surplus low-grade thermal energy unused for effective storage and utilization, or they fail to classify the grade of collected thermal energy, resulting in high- and low-grade thermal energy being mixed in the same storage unit, thus failing to achieve cascade energy utilization. Furthermore, existing systems' pumps and other electrical equipment largely rely on municipal power grids, failing to achieve self-consumption of PVT photovoltaic power generation, leading to high system energy consumption and underutilizing the clean and low-carbon technological advantages.

[0006] Fourth, the existing heat pump coupled heating system lacks adaptability and heating stability. Most existing systems only have a single heat source heat pump mode and a direct water tank supply mode, resulting in poor flexibility in switching between modes and an inability to adapt to different seasons, irradiance conditions, and load demands across various scenarios. When the water temperature in the storage tank is at a moderate level and cannot meet the direct supply temperature requirements, there is a lack of a heat pump mode that uses the hot water from the tank as the primary heat source. Either the tank's heat energy is abandoned in favor of an auxiliary heat source, resulting in a waste of high-grade heat energy, or additional energy is consumed to supplement the tank's heat and raise the water temperature, increasing system energy consumption. Simultaneously, the system lacks sufficient safe heating capacity under extreme low temperatures, making it difficult to guarantee heating stability.

[0007] To address the core issues in existing technologies, such as insufficient synergy of cross-seasonal heat storage schemes, slow thermal response speed of heat storage and release, low heat storage efficiency, large heat loss over long periods, insufficient cascade utilization of solar energy, poor flexibility of heating conditions, and high energy consumption during system operation, there is an urgent need to develop a cross-seasonal heating system that couples photovoltaic thermal energy with hot water storage tank-soil thermal energy storage, features fast heat storage speed, sensitive thermal response, low heat loss, high energy utilization efficiency, stable heating, high safety, and convenient construction. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a cross-seasonal heating system with low heat loss, fast heat storage and heating and heat release response, and higher energy utilization efficiency.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A cross-seasonal heating system includes a photovoltaic thermal collector unit, an underground heat storage unit, and an external heat supply interface. The collector side of the photovoltaic thermal collector unit is connected to the underground heat storage unit and serves as the input heat source. The underground heat storage unit is connected to the external heat supply interface and is used to output heat. The system is characterized in that the power generation end of the photovoltaic thermal collector unit is connected to an energy storage battery and serves as the power source for the system's electrical components. A water source heat pump unit is also connected between the underground heat storage unit and the external heat supply interface through a control pipeline system.

[0010] In this way, the system achieves self-consumption of photovoltaic power generation, providing clean electricity for system operation. Simultaneously, the installed water source heat pump unit can enhance the heat source quality to provide heating during the later stages of the heating season when the underground heat storage unit's heat is insufficient, thus further improving energy utilization efficiency.

[0011] Furthermore, the photovoltaic-thermal heat collection unit includes a core photovoltaic-thermal integrated panel array (which can simultaneously realize photovoltaic power generation and solar heat collection). Its power generation end is connected to the battery via a charging cable. The battery is equipped with an inverter component, which is connected to each electrical component in the system through a corresponding power supply circuit.

[0012] More specifically, the battery supplies power to the solar collector hot water circulation pump, the charging circulation pump, the water tank and buried pipe heat release circulation pump, the water source heat pump, and the secondary side water pump of the water source heat pump through the power supply circuits for the collector hot water circulation pump, the charging circulation pump, the water tank and buried pipe heat release circulation pump, the water source heat pump, and the secondary side water pump of the water source heat pump. This enables the solar power generation to be self-consumed, effectively reducing the system's dependence on the municipal power grid and enhancing the system's clean and low-carbon attributes.

[0013] Furthermore, the collector side of the photovoltaic thermal collector unit is connected to the hot side of the collector side heat exchanger through the collector hot water circulation pipeline and the collector hot water circulation pump, forming a closed-loop heat collection cycle. (In practice, the collector side heat exchanger is preferably a partition plate heat exchanger.) The cold side of the collector side heat exchanger is connected to the charging circulation pipeline of the control pipeline system and connected to the underground thermal storage unit. The output end of the charging circulation pipeline is connected to the external heating interface. The charging circulation pipeline is also connected to the evaporator side of the water source heat pump unit. The output end of the water source heat pump unit is connected to the external heating interface.

[0014] This achieves isolated heat exchange between the collector side and the storage side, preventing impurities and scale in the collector circuit from entering the underground storage unit and ensuring long-term stable operation of the system. The collector-side heat exchanger can, according to the collector outlet water temperature of the photovoltaic-thermal integrated panel array, control the pipeline system to deliver heat energy of different grades to the high-grade and low-grade heat storage units of the underground storage unit, realizing graded storage and tiered utilization of solar thermal energy and avoiding energy waste caused by mixed storage of heat energy of different grades.

[0015] Furthermore, the underground thermal storage unit includes a high-grade thermal reservoir located in the center and a low-grade thermal reservoir located in the surrounding area; the high-grade thermal reservoir is a buried hot water storage tank, and the low-grade thermal reservoir is a network of buried pipes arranged in a closed loop around the hot water storage tank, the network of buried pipes being buried in the rock and soil surrounding the hot water storage tank. Furthermore, the drilling depth of the buried pipe network is greater than the bottom depth of the hot water storage tank.

[0016] In this way, a ring-shaped thermal enclosure layer is formed between the radial outer side of the hot water storage tank and the natural rock and soil, which blocks the radial heat loss from the high-grade heat storage to the surrounding natural rock and soil, thereby reducing heat loss and improving the efficiency of heat storage and utilization.

[0017] Furthermore, the hot water storage tank is a regional parallel hot water storage tank, which includes four independent water storage chambers arranged in a grid pattern, divided by an intermediate earthen embankment of the original soil mass. The four water storage chambers are connected in parallel. This allows for independent heat filling and release of a single chamber as well as coordinated operation of multiple chambers, making the use and control more flexible.

[0018] In this way, the hot water storage tank is divided into four independent water storage chambers—the first, second, third, and fourth—in a grid pattern by an in-situ pre-reserved intermediate earthen embankment. These four chambers are connected in parallel. This allows for independent heating and heat release in a single chamber or coordinated operation of multiple chambers. The intermediate earthen embankment does not require additional concrete partition walls, effectively reducing underground construction costs and operational difficulties.

[0019] Furthermore, the water storage cavity adopts a trapezoidal cross-section structure that is wider at the top and narrower at the bottom. This better adapts to the slope stability requirements of excavating undisturbed underground soil.

[0020] Furthermore, the entire inner wall of the water storage chamber is lined with a high-polymer waterproof and seepage-proof membrane. This ensures a reliable waterproof and seepage-proof effect.

[0021] Furthermore, each water storage chamber is equipped with a water tank insulation cover on top, which effectively reduces heat loss from the top of the hot water storage tank.

[0022] Furthermore, each water storage chamber is equipped with a layered water intake assembly, which includes three layers of tubular water intake devices arranged horizontally on the inner wall along the depth direction of the water storage chamber. The tubular water intake devices have water outlets along their length on the inner side facing the water storage chamber. Both ends of each layer of tubular water intake devices are connected upwards in parallel to the heat charging circulation pipeline of the control pipeline system through dedicated water intake device pipes. Then, they are connected upwards to the parallel water tank direct supply heat exchanger and water source heat pump unit through the water tank heat release pipeline. Each layer of tubular water intake devices is equipped with an independent solenoid valve group on its dedicated water intake device pipes at both ends.

[0023] This design allows for precise and independent control of water distribution and extraction within the storage chamber, enabling users to select either top-to-bottom, middle-to-bottom, or any combination of two tubular water extractors based on the water temperature stratification within the chamber. This ensures precise and independent control of water distribution and extraction within each chamber, with each tubular water extractor individually controllable via a corresponding solenoid valve assembly. The ability to select any two tubular water extractors based on the water temperature stratification within the storage chamber effectively preserves the high-grade heat energy within the chamber and avoids disrupting the water temperature stratification during the heat dissipation process.

[0024] Furthermore, the heat release pipeline of the water tank is sequentially equipped with a heat release valve group, a heat release circulation valve group, and a water tank direct supply operating condition valve group, and is connected to the input end of a water tank direct supply heat release exchanger. The output end of the water tank direct supply heat release exchanger is connected to the external heating interface through a water tank direct supply output pipeline equipped with a water tank direct supply operating condition load side circulation pump. A water tank and buried pipe heat release circulation pump is installed on the heat release pipeline between the heat release circulation valve group and the water tank direct supply operating condition valve group. A heat pump supplementary heating pipeline is also bypassed on the heat release pipeline between the heat release circulation valve group and the water tank direct supply operating condition valve group and is connected to the evaporator side of the water source heat pump unit. A water source heat pump primary side valve group is installed on the heat pump supplementary heating pipeline.

[0025] In this way, the heat supplied by the water tank can be directly output through the water tank direct supply heat exchanger, or it can be output after the heat quality is improved by the water source heat pump unit 17 when the heat is insufficient.

[0026] Furthermore, a flow stabilizing device is installed on the outside of the tubular water collector in the middle layer. The flow stabilizing device is a tubular cloth bag fixedly sleeved outside the water inlet. The lower surface of the tubular cloth bag has openings evenly spaced along its length.

[0027] In this way, during the heat storage process in the water tank, water is typically introduced from the top and extracted from the bottom, maintaining high-grade heat water at the top. At this time, the filter bags in the middle layer hang naturally without affecting the natural flow of water from top to bottom. However, when the upper part of the tank is full of high-grade heat water, and the heat grade of the input water decreases (due to insufficient sunlight, etc.), water can be introduced from the middle layer and discharged from the bottom. The water flow from the outlet will push the tubular filter bags outward to a horizontal position. At this point, the water flows downward from the lower surface of the filter bags into the lower part of the storage chamber, minimizing interference with the high-grade heat water at the top and ensuring that the high-grade heat water remains at the top. Then, when external heating is needed, hot water is output from the top and returned from the bottom, thus remaining unaffected. Therefore, this system better facilitates the management of water input and output.

[0028] Furthermore, the buried pipe group includes buried pipes buried in the surrounding soil around the hot water storage tank. The buried pipes are arranged in a rectangular circle around the hot water storage tank. The upper ends of each buried pipe are connected to two buried pipe mains through buried pipe valve groups. The buried pipe mains are connected to the heat charging circulation pipeline through buried pipe heat charging circulation valve groups. The two buried pipe mains are also connected by bypass pipes equipped with buried pipe heat release valve groups and connected to the evaporator side of the water source heat pump unit.

[0029] This arrangement of underground pipes creates a continuous annular thermal enclosure between the outer radial side of the hot water storage tank and the natural soil and rock, effectively blocking radial heat loss from the tank. During the summer non-heating season, the underground pipe network receives low-grade heat energy generated by the photovoltaic thermal collectors through the underground pipe charging and circulation valve group, releasing the heat into the surrounding soil and rock. This raises the temperature of the soil and rock in the annular enclosure area, reducing the temperature difference between the high-grade hot water storage tank and the surrounding natural soil and rock, effectively suppressing radial heat loss during seasonal heat storage. During the winter heating season, the underground pipe network acts as a stable heat source for the water source heat pump unit through the underground pipe heat release valve group, achieving improved utilization of low-grade heat energy. Simultaneously, leveraging the structural characteristics of the annular layout, it continuously forms a thermal enclosure for the high-grade hot water storage tank, ensuring effective heat storage. The underground pipes can be vertical U-shaped or sleeve-type, adaptable to different engineering geological conditions, convenient to construct, and offer stable heat exchange efficiency.

[0030] Furthermore, the water source heat pump unit obtains power through the water source heat pump power supply circuit. Its evaporator side is switchably connected to the hot water storage tank and the underground pipe group through the primary side valve group of the water source heat pump. The two output pipes connected from its condenser side are sequentially equipped with a secondary side valve group of the water source heat pump, a secondary side water pump of the water source heat pump, and a heat pump to the heating network heating valve group, and then connected to the external heating interface. The farthest end of the charging circulation pipeline is equipped with a heat pump to the water tank heat replenishment valve group, and then connected to the output pipe between the secondary side valve group of the water source heat pump and the heat pump to the heating network heating valve group.

[0031] This system allows for switchable connection between the secondary valve group and the secondary water pump of the water source heat pump and the hot water storage tank and external heating interface. By controlling the on / off state of the heat pump's heat replenishment valve group for the water tank and the heating network valve group, three core operating modes are achieved: heat replenishment, water tank heat source quality improvement heating, and emergency direct supply from the buried pipe heat source. Simultaneously, it enables the photovoltaic thermal collector unit to directly supply heat to the external heating interface.

[0032] Furthermore, the control pipeline system includes six independent closed-loop operating branches: a high-grade heat storage circulation branch, a low-grade heat storage circulation branch, a direct heating branch from the hot water storage tank, a heat pump supplementary heating branch, a heat pump quality improvement heating branch from the water tank heat source, and an emergency direct heating branch from the buried pipe heat source. The high-grade thermal storage circulation branch includes the thermal charging circulation pipeline and the thermal charging circulation pump and the water tank thermal charging circulation valve group installed thereon. The water tank thermal charging circulation valve group is located on the thermal charging circulation pipeline between the connection point of the water intake pipe and the connection point of the buried main pipe. The high-grade thermal storage circulation branch also includes each layer of tubular water intake and its dedicated water intake pipes at both ends, as well as the solenoid valve group installed on the water intake pipe. The low-grade heat storage circulation branch includes the heat charging circulation pipeline and the heat charging circulation pump installed thereon, as well as the underground pipe group, the underground pipe valve group, the underground pipe trunk and the underground pipe heat charging circulation valve group installed thereon. The direct heating branch of the hot water storage tank includes a water tank heat release pipeline and its water tank heat release valve group, heat release circulation valve group, water tank and buried pipe heat release circulation pump, water tank direct supply condition valve group and water tank direct supply heat exchanger, as well as the water tank direct supply output pipeline and water tank direct supply condition load side circulation pump at the output end of the water tank direct supply heat exchanger and the external heating interface. The heat pump supplementary heating branch includes the heat pump supplementary heating pipeline and the water source heat pump primary side valve group and water source heat pump unit on it. The water tank heat source heat pump quality improvement and heating branch includes the water tank and buried pipe heat release circulation pump, heat release circulation valve group, water tank heat release valve group, water source heat pump unit and heat pump to heat network heating valve group, as well as their respective corresponding pipelines and external heating interfaces. The underground pipe heat source emergency direct supply branch includes a water tank and underground pipe heat release circulation pump, heat release circulation valve group, underground pipe heat release valve group, water source heat pump unit, heat pump to heat network heating valve group and their corresponding pipelines, as well as external heating connection.

[0033] This allows for flexible and convenient switching between various operating conditions. All heating methods utilize isolated heat exchange, preventing impurities from the heat collection circuit from entering the hot water storage tank and underground pipe network. During implementation, all valve groups use electrically interlocked electric valves, with valve groups on the same branch opening and closing synchronously. Valve groups operating under opposing conditions are interlocked and locked to prevent simultaneous opening, effectively avoiding cross-flow of media and hydraulic imbalance between different operating conditions. All pumps in the system are variable frequency centrifugal pumps, which can adjust the flow rate in real time according to solar irradiance, building heat load requirements, and hot water storage tank temperature, achieving energy-saving operation of the system and ensuring dynamic matching of media circulation under various operating conditions.

[0034] Therefore, this system can flexibly switch between six independent closed-loop operating conditions through precise control of valve groups and pumps, based on seasonal changes, solar radiation intensity, water temperature stratification in the hot water storage tank, and building heat load requirements, to achieve adaptive operation across all scenarios.

[0035] In summary, this system has the following core beneficial effects: 1. Optimized heat storage and release performance, effectively reducing reliance on heat pump operation. This invention adopts a four-chamber parallel hot water storage tank structure, enabling sequential, tiered heat storage in a single chamber, effectively shortening the heat storage and heating cycle. During the heating season, independent heat release from each chamber better matches load changes, improving thermal response speed. It is equipped with a three-layer independently controllable tiered water intake assembly, allowing flexible selection of water distribution and intake layers based on water temperature stratification, avoiding disturbance to water temperature stratification and effectively preserving high-grade heat energy. The newly added water tank heat source heat pump upgrading heating branch can use warm water from the tank as a heat source for upgrading heating when the water temperature in the tank cannot meet direct supply requirements in the later stages of the heating season, effectively reducing system operating energy consumption and improving the utilization rate of stored heat energy across seasons.

[0036] 2. Effectively reduces long-term heat loss during cross-seasonal heat storage and improves the availability of heat storage. This invention deeply couples water tank heat storage with buried pipe heat storage in rock and soil. Through a closed-loop network of buried pipes surrounding the hot water storage tank, the surplus low-grade solar energy in summer raises the temperature of the surrounding rock and soil, forming a ring-shaped thermal enclosure between the high-grade hot water storage tank and the natural rock and soil. This reduces the temperature difference between the hot water storage tank and the surrounding environment, effectively suppressing radial heat loss. It eliminates the need for thickened underground insulation layers, solving the problems of easy aging and damage of traditional insulation layers and the gradual decline in heat loss control effectiveness over the years, thus effectively improving the availability of cross-seasonal heat storage.

[0037] 3. Achieving full-grade cascade utilization of solar energy, effectively improving system self-consistency. This invention simultaneously realizes photovoltaic power generation and solar thermal collection through a photovoltaic-thermal integrated panel array. The photovoltaic power generated is stored in energy storage batteries to power water pumps, valve groups, and heat pump units within the system, achieving self-generation and self-consumption of clean electricity and effectively reducing the system's dependence on the municipal power grid. Simultaneously, based on the temperature of the collected water outlet, high-grade thermal energy can be stored in a water tank thermal storage unit, while low-grade thermal energy can be stored in a ring-shaped underground pipe network, achieving full-grade cascade utilization of solar energy. This solves the problems of poor photovoltaic-thermal synergy and waste of low-grade thermal energy in traditional PVT systems, effectively improving energy utilization efficiency.

[0038] 4. Flexible adaptation to multiple operating conditions, ensuring greater stability and reliability of heating. This invention sets up six independent closed-loop operating conditions: high-grade heat storage, low-grade heat storage, direct heating from the water tank, heat pump supplementary heating, emergency direct supply from the buried pipe heat source, and heat pump-enhanced heating from the water tank heat source. These conditions can be flexibly switched according to different seasons, solar irradiance conditions, heat load demands, and water tank temperatures. This achieves a full-grade heat storage during the non-heating season, priority direct supply during the heating season, enhanced utilization of medium-temperature water, and safety assurance under extreme conditions. Compared with traditional single-condition systems, this invention offers stronger adaptability and improves the stability and reliability of heating.

[0039] 5. Convenient construction, controllable cost, and strong adaptability to various scenarios. The hot water storage tank of this invention uses in-situ pre-reserved earthen embankments in the original soil to achieve cavity separation, eliminating the need for additional concrete partition walls, effectively reducing underground construction costs and operational difficulties; the water storage cavity adopts a trapezoidal cross-section, adapting to the slope stability requirements of excavating original soil, simplifying the construction process, and facilitating waterproofing and seepage prevention; the system can achieve large-scale expansion through parallel connection of multiple units, adapting to different scale application scenarios such as civil buildings, public buildings, and district centralized heating, and possessing good conditions for promotion and application. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the cross-seasonal heating system of the present invention.

[0041] Figure 2 for Figure 1 The diagram shows a layered water intake assembly inside the water storage chamber.

[0042] Figure 3 for Figure 2 A lateral schematic diagram of a single tubular water intake device in the middle layer.

[0043] Figure 4 This is a plan view of the hot water storage tank and the ring-shaped underground pipe group, used to show the plan layout of the four independent water storage chambers arranged in a grid pattern, as well as the arrangement of the underground pipe array that is arranged in a closed loop around the hot water storage tank.

[0044] Figure 5 for Figure 4 A schematic diagram of the frontal view. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0046] Example 1: See Figure 1-5 As shown, a cross-seasonal heating system includes a photovoltaic thermal collector unit, an underground heat storage unit, and an external heat supply interface. The collector side of the photovoltaic thermal collector unit is connected to the underground heat storage unit and serves as the input heat source. The underground heat storage unit is connected to the external heat supply interface and is used to output heat. The system is characterized in that the generator end of the photovoltaic thermal collector unit is connected to an energy storage battery and serves as the power source for the system's electrical components. A water source heat pump unit is also connected between the underground heat storage unit and the external heat supply interface through a control pipeline system.

[0047] In this way, the system achieves self-consumption of photovoltaic power generation, providing clean electricity for system operation. Simultaneously, the installed water source heat pump unit can enhance the heat source quality to provide heating during the later stages of the heating season when the underground heat storage unit's heat is insufficient, thus further improving energy utilization efficiency.

[0048] The photovoltaic and solar thermal collector unit includes a photovoltaic and solar thermal integrated panel array 1 as the core (which can simultaneously realize photovoltaic power generation and solar thermal collection). Its power generation end is connected to the storage battery 3 through the charging cable 2. The storage battery 3 is equipped with an inverter component and is connected to each electrical component in the system through the power supply circuit.

[0049] More specifically, the battery supplies power to the collector hot water circulation pump 5, the charging circulation pump 10, the water tank and buried pipe heat release circulation pump 23, the water source heat pump unit 17, the water source heat pump secondary side pump 19, and all electric valve groups in the system through the collector hot water circulation pump power supply circuit 6, the charging circulation pump power supply circuit 8, the water tank and buried pipe heat release circulation pump power supply circuit 27, the water source heat pump power supply circuit 14, and the water source heat pump secondary side pump power supply circuit 16. This enables the photovoltaic power generation to be self-consumed, effectively reducing the system's dependence on the municipal power grid and enhancing the system's clean and low-carbon attributes.

[0050] In this system, the collector side of the photovoltaic-thermal integrated panel array 1 is connected to the hot side of the collector side heat exchanger 7 via the collector hot water circulation pipe 4 and the collector hot water circulation pump 5, forming a closed-loop heat collection circulation. (In practice, the collector side heat exchanger 7 is preferably a partition plate heat exchanger.) The cold side of the collector side heat exchanger is connected to the charging circulation pipe 9 of the control pipe system and to the underground heat storage unit. The output end of the charging circulation pipe 9 is connected to the external heating interface 20. The charging circulation pipe 9 is also connected to the evaporator side of the water source heat pump unit. The output end of the water source heat pump unit is connected to the external heating interface 20.

[0051] This achieves isolated heat exchange between the collector side and the storage side, preventing impurities and scale in the collector circuit from entering the underground heat storage unit and ensuring long-term stable operation of the system. The collector-side heat exchanger 7 can, according to the collector outlet water temperature of the photovoltaic-thermal integrated panel array 1, control the pipeline system to deliver heat energy of different grades to the high-grade heat storage and low-grade heat storage of the underground heat storage unit, realizing the graded storage and cascade utilization of solar thermal energy and avoiding energy waste caused by the mixed storage of heat energy of different grades.

[0052] The underground thermal storage unit includes a high-grade thermal reservoir located in the center and a low-grade thermal reservoir located in the surrounding area. The high-grade thermal reservoir is a buried hot water storage tank, and the low-grade thermal reservoir is a group of buried pipes arranged in a closed loop around the hot water storage tank. The buried pipes are buried in the rock and soil around the hot water storage tank. The drilling depth of the buried pipes is greater than the bottom depth of the hot water storage tank.

[0053] In this way, a ring-shaped thermal enclosure layer is formed between the radial outer side of the hot water storage tank and the natural rock and soil, which blocks the radial heat loss from the high-grade heat storage to the surrounding natural rock and soil, thereby reducing heat loss and improving the efficiency of heat storage and utilization.

[0054] The hot water storage tank is a regional parallel hot water storage tank, which includes four independent water storage chambers arranged in a grid pattern, divided by an intermediate earthen embankment of the original soil. The four water storage chambers are connected in parallel. This allows for independent heat filling and release of a single chamber as well as coordinated operation of multiple chambers, making the use and control more flexible.

[0055] More specifically, see Figure 4 and 5 The hot water storage tank is divided into four independent water storage chambers arranged in a grid pattern: the first water storage chamber 57, the second water storage chamber 58, the third water storage chamber 59, and the fourth water storage chamber 60, by an intermediate earthen embankment 65 pre-reserved in the original soil. The four water storage chambers are connected in parallel, which can realize independent heat filling and heat release of a single chamber or coordinated operation of multiple chambers. The intermediate earthen embankment 65 does not require additional concrete partition walls, effectively reducing the cost and difficulty of underground construction.

[0056] The water storage chamber adopts a trapezoidal cross-section structure that is wider at the top and narrower at the bottom. This better adapts to the slope stability requirements of excavating undisturbed underground soil.

[0057] The inner wall of the water storage chamber is entirely covered with a high-polymer waterproof and seepage-proof membrane. This ensures a reliable waterproof and seepage-proof effect.

[0058] Each water storage chamber is equipped with a water tank insulation cover 31, which effectively reduces the heat loss from the top of the hot water storage tank.

[0059] Among them, (combined) Figure 2 and Figure 3 As shown, each water storage chamber is equipped with a layered water intake assembly, which includes three layers of tubular water intake devices (upper tubular water intake device 45, middle tubular water intake device 46, and lower tubular water intake device 47) horizontally arranged on the inner wall along the depth direction of the water storage chamber. Each tubular water intake device has a water outlet along its length on the inner side facing the water storage chamber. Both ends of each layer of tubular water intake device are connected upwards in parallel via dedicated water intake connectors (upper tubular water intake connector 52, middle tubular water intake connector 50, and lower tubular water intake connector 48). The heat-charging circulation pipeline 9 is connected to the control pipeline system, and then the heat release pipeline of the water tank is connected upward to the parallel water tank direct supply heat exchanger and water source heat pump unit 17. Each layer of tubular water collector is equipped with an independent solenoid valve group (upper tubular water collector on / off valve 39, middle tubular water collector on / off valve 40, lower tubular water collector on / off valve 41). In practice, the upper tubular water collector on / off valve 39, middle tubular water collector on / off valve 40 and lower tubular water collector on / off valve 41 are centrally installed and form a water collector valve group 25.

[0060] This design allows for precise and independent control of water distribution and extraction within the storage chamber, enabling users to select either top-to-bottom, middle-to-bottom, or any combination of two tubular water extractors based on the water temperature stratification within the chamber. This ensures precise and independent control of water distribution and extraction within each chamber, with each tubular water extractor individually controllable via a corresponding solenoid valve assembly. The ability to select any two tubular water extractors based on the water temperature stratification within the storage chamber effectively preserves the high-grade heat energy within the chamber and avoids disrupting the water temperature stratification during the heat dissipation process.

[0061] The heat release pipeline of the water tank is sequentially equipped with a heat release valve group 35, a heat release circulation valve group 24, and a water tank direct supply valve group 22, and is connected to the input end of a water tank direct supply heat exchanger. The output end of the water tank direct supply heat exchanger is connected to the external heating interface 20 through a water tank direct supply output pipeline equipped with a water tank direct supply load-side circulation pump 21. A water tank and buried pipe heat release circulation pump 23 is installed on the heat release pipeline between the heat release circulation valve group 24 and the water tank direct supply valve group 22. A heat pump supplementary heating pipeline is also bypassed on the heat release pipeline between the heat release circulation valve group 24 and the water tank direct supply valve group 22 and connected to the evaporator side of the water source heat pump unit 17. A water source heat pump primary side valve group 15 is installed on the heat pump supplementary heating pipeline.

[0062] In this way, the heat supplied by the water tank can be directly output through the water tank direct supply heat exchanger, or it can be output after the heat quality is improved by the water source heat pump unit 17 when the heat is insufficient.

[0063] Among them, a flow stabilizing device is provided on the outside of the tubular water collector 46 in the middle layer. The flow stabilizing device is a tubular cloth bag 68 fixedly sleeved outside the water inlet. The lower surface of the tubular cloth bag 68 has openings evenly spaced along the length direction.

[0064] In this way, during the heat storage process in the water tank, water is typically introduced from the top and extracted from the bottom, maintaining high-grade heat water at the top. At this time, the filter bags in the middle layer hang naturally without affecting the natural flow of water from top to bottom. However, when the upper part of the tank is full of high-grade heat water, and the heat grade of the input water decreases (due to insufficient sunlight, etc.), water can be introduced from the middle layer and discharged from the bottom. The water flow from the outlet will push the tubular filter bags outward to a horizontal position. At this point, the water flows downward from the lower surface of the filter bags into the lower part of the storage chamber, minimizing interference with the high-grade heat water at the top and ensuring that the high-grade heat water remains at the top. Then, when external heating is needed, hot water is output from the top and returned from the bottom, thus remaining unaffected. Therefore, this system better facilitates the management of water input and output.

[0065] Among them, combined Figure 4 , Figure 5 As shown, the buried pipe group includes buried pipes 33 buried in the outer soil 66 around the hot water storage tank. The buried pipes are arranged in a rectangular circle around the hot water storage tank. The upper ends of each buried pipe are connected to two buried pipe trunks 61 through buried pipe valve groups 12. The buried pipe trunks are connected to the heat charging circulation pipeline 9 through buried pipe heat charging circulation valve groups 34. The two buried pipe trunks are also connected by bypass pipes equipped with buried pipe heat release valve groups 36 and connected to the evaporator side of the water source heat pump unit 17.

[0066] In this way, the buried pipes form a continuous annular thermal enclosure between the radial outer side of the hot water storage tank and the natural rock and soil, which can simultaneously block the radial heat loss of the hot water storage tank to the outside. During the summer non-heating season, the buried pipe group receives low-grade heat energy generated by the photovoltaic thermal collector unit through the buried pipe heat-charging circulation valve group 34, and releases the heat to the surrounding rock and soil, raising the temperature of the rock and soil in the annular enclosure area, reducing the temperature difference between the high-grade hot water storage tank and the surrounding natural rock and soil, and effectively suppressing radial heat loss from cross-seasonal heat storage. During the winter heating season, the buried pipe group serves as a stable heat source for the water source heat pump unit 17 through the buried pipe heat release valve group 36, realizing the improved utilization of low-grade heat energy. At the same time, relying on the structural characteristics of the annular layout, it continuously forms a thermal enclosure for the high-grade hot water storage tank, ensuring the heat storage effect. The buried pipes can be vertical U-shaped buried pipes or sleeve-type buried pipes, which are suitable for different engineering geological conditions, convenient to construct, and have stable heat exchange efficiency.

[0067] The water source heat pump unit obtains power through the water source heat pump power supply circuit 14. Its evaporator side is switchably connected to the hot water storage tank and the underground pipe group through the water source heat pump primary side valve group 15. The two output pipes connected from its condenser side are sequentially installed with a water source heat pump secondary side valve group 18, a water source heat pump secondary side water pump 19 and a heat pump to the heating network heating valve group 38 and then connected to the external heating interface 20. The furthest end of the charging circulation pipeline 9 is installed with a heat pump to the water tank heat replenishment valve group 37 and then connected to the output pipe between the water source heat pump secondary side valve group 18 and the heat pump to the heating network heating valve group 38.

[0068] In this way, the secondary side valve group 18 and the secondary side water pump 19 of the water source heat pump can be switched to connect to the hot water storage tank and the external heating interface 20. By controlling the on / off of the heat pump to the water tank heat replenishment valve group 37 and the heat pump to the heating network supply valve group 38, three core operating modes can be realized: heat replenishment, water tank heat source quality improvement heating, and underground pipe heat source emergency direct supply. At the same time, it also enables the photovoltaic thermal collector unit to directly supply heat to the external heating interface.

[0069] The control pipeline system includes six independent closed-loop operating branches: a high-grade heat storage circulation branch, a low-grade heat storage circulation branch, a direct heating branch from the hot water storage tank, a heat pump supplementary heating branch, a heat pump quality improvement heating branch from the water tank heat source, and an emergency direct heating branch from the buried pipe heat source. Each branch is equipped with a corresponding pump body, valve group, and pipeline. The high-grade thermal storage circulation branch includes the thermal charging circulation pipeline 9 and the thermal charging circulation pump 10 and the water tank thermal charging circulation valve group 11 installed thereon. The water tank thermal charging circulation valve group 11 is located on the thermal charging circulation pipeline 9 between the connection point of the water intake pipe and the connection point of the buried main pipe. The high-grade thermal storage circulation branch also includes each layer of tubular water intake and its dedicated water intake pipes at both ends, as well as the solenoid valve group (upper tubular water intake on / off valve 39, middle tubular water intake on / off valve 40, and lower tubular water intake on / off valve 41) installed on the water intake pipes. The low-grade heat storage circulation branch includes the heat charging circulation pipeline 9 and the heat charging circulation pump 10 installed thereon, as well as the underground pipe group, the underground pipe valve group 12, the underground pipe main pipe and the underground pipe heat charging circulation valve group 34 installed thereon. The direct heating branch of the hot water storage tank includes a water tank heat release pipe and a water tank heat release valve group 35, a heat release circulation valve group 24, a water tank and buried pipe heat release circulation pump 23, a water tank direct supply condition valve group 22 and a water tank direct supply heat release exchanger, as well as a water tank direct supply output pipe and a water tank direct supply condition load side circulation pump 21 at the output end of the water tank direct supply heat release exchanger and an external heating interface 20; The heat pump supplementary heating branch includes the heat pump supplementary heating pipeline and the water source heat pump primary side valve group 15 and water source heat pump unit 17. The water tank heat source heat pump quality improvement and heating branch includes a water tank and buried pipe heat release circulation pump 23, heat release circulation valve group 24, water tank heat release valve group 35, water source heat pump unit 17, and heat pump to heat network heating valve group 38, as well as their respective corresponding pipelines and external heating interface 20. The underground pipe heat source emergency direct supply branch includes a water tank and underground pipe heat release circulation pump 23, heat release circulation valve group 24, underground pipe heat release valve group 36, water source heat pump unit 17, heat pump to heat network heating valve group 38 and their corresponding pipelines and external heating interface 20.

[0070] This allows for flexible and convenient switching between various operating conditions. All heating methods utilize isolated heat exchange, preventing impurities from the heat collection circuit from entering the hot water storage tank and underground pipe network. During implementation, all valve groups use electrically interlocked electric valves, with valve groups on the same branch opening and closing synchronously. Valve groups operating under opposing conditions are interlocked and locked to prevent simultaneous opening, effectively avoiding cross-flow of media and hydraulic imbalance between different operating conditions. All pumps in the system are variable frequency centrifugal pumps, which can adjust the flow rate in real time according to solar irradiance, building heat load requirements, and hot water storage tank temperature, achieving energy-saving operation of the system and ensuring dynamic matching of media circulation under various operating conditions.

[0071] Therefore, this system can flexibly switch between six independent closed-loop operating conditions through precise control of valve groups and pumps, based on seasonal changes, solar radiation intensity, water temperature stratification in the hot water storage tank, and building heat load requirements, to achieve adaptive operation across all scenarios.

[0072] More specifically, the specific operating modes for each of the above conditions are as follows, where each temperature threshold satisfies t1 < t2 < t3 < t4 < t5 < t6. t1 is the lower limit temperature of the heat exchange medium corresponding to the lowest outdoor ambient temperature in winter; t2 is the lower limit temperature corresponding to low-grade solar thermal collectors during the non-heating season; t3 is the critical temperature at which the water storage chamber cannot meet the requirements for direct heating; t4 is the minimum water supply temperature required for direct heating of the building; t5 is the lower limit temperature corresponding to high-grade solar thermal collectors; and t6 is the maximum designed heat storage temperature of the hot water storage tank. 1. High-grade cross-seasonal heat storage conditions This operating condition applies to situations where there is sufficient solar irradiance during the non-heating season, the water temperature of the photovoltaic and solar thermal integrated panel array collector is ≥t5, and the hot water storage tank has not completed heat storage. At this time, the collector hot water circulation pump 5 and the charging circulation pump 10 are turned on, and the water tank charging circulation valve group 11 and the water intake valve group 25 corresponding to the target water storage chamber are turned on simultaneously, while all other valve groups are turned off. The medium forms two closed-loop circulations. One is the solar collector circulation: photovoltaic-thermal integrated panel array 1 → solar collector hot water circulation pipe 4 → solar collector hot water circulation pump 5 → solar collector side heat exchanger 7 hot side → photovoltaic-thermal integrated panel array 1, completing solar heat collection and heat transfer; the other is the high-grade heat storage circulation: solar collector side heat exchanger 7 cold side → heat charging circulation pump 10 → heat charging circulation pipe 9 → water tank heat charging circulation valve group 11 → water tank water intake valve group 25 → target water storage chamber → lower tubular water intake 47 → lower tubular water intake on / off valve 44 → water tank water intake valve group 25 → solar collector side heat exchanger 7 cold side. This operating mode adopts a single-cavity sequential staged heating mode. First, the first water storage cavity 57 is heated. When the water temperature in the cavity reaches the designed heat storage temperature t6, the system switches sequentially to the second water storage cavity 58, the third water storage cavity 59, and the fourth water storage cavity 60. This effectively shortens the heat storage and heating cycle. In addition, the water intake method of hot water entering from the upper layer and cold water exiting from the lower layer can effectively maintain the natural temperature stratification of "hot at the top and cold at the bottom" in the water storage cavity, avoiding the mixing of high and low grade heat energy.

[0073] 2. Low-grade heat storage and enhanced thermal enclosure conditions This operating condition is applicable when solar irradiance is insufficient during the non-heating season, the outlet water temperature of the photovoltaic-thermal integrated panel array is in the range of t2~t5, or when all four water storage chambers have completed full heat storage and surplus solar energy needs to be stored at a low grade. In this case, the collector hot water circulation pump 5 and the charging circulation pump 10 are turned on, and the underground pipe charging circulation valve group 34 and the underground pipe valve group 12 are turned on simultaneously, while all other valve groups are closed. The medium forms two closed-loop circulations: one is the collector circulation: photovoltaic-thermal integrated panel array 1 → collector hot water circulation pipeline 4 → collector hot water circulation pump 5 → collector-side heat exchanger 7 (hot side) → photovoltaic-thermal integrated panel array 1; the other is the low-grade heat storage circulation: collector-side heat exchanger 7 (cold side) → charging circulation pump 10 → charging circulation pipeline 9 → underground pipe charging circulation valve group 34 → underground pipe valve group 12 → underground pipe 33 → collector-side heat exchanger 7 (cold side). This operating condition stores the low-grade heat energy generated by the photovoltaic thermal system in the soil and rock surrounding the buried pipe group, realizing the effective utilization of low-grade heat energy. At the same time, it increases the soil and rock temperature in the ring-shaped enclosure area, strengthens the thermal enclosure effect of the high-grade hot water storage tank, and effectively reduces the radial heat loss of cross-seasonal heat storage.

[0074] 3. Direct heating supply from hot water storage tanks This operating condition is the priority operating condition during the heating season and is applicable when the water temperature in the storage chamber is ≥t4 and can meet the requirements of direct heating for the building. In this condition, the load-side circulation pump 21 for direct supply to the water tank is activated, and simultaneously the water tank heat release valve group 35, the water tank direct supply valve group 22, the water tank water intake valve group 25 corresponding to the target storage chamber, the upper tubular water intake on / off valve 39, and the lower tubular water intake on / off valve 41 are activated. All other valve groups are closed. A closed-loop direct supply circulation is formed: Target storage chamber → Upper tubular water intake 45 → Upper tubular water intake on / off valve 39 → Water tank water intake valve group 25 → Water tank heat release valve group 35 → Water tank direct supply valve group 22 → Water tank direct supply load-side circulation pump 21 → External heating interface 20 → Target storage chamber → Lower tubular water intake 47 → Lower tubular water intake on / off valve 41 → Water tank water intake valve group 25. In this operating condition, there is no need to start the water source heat pump unit 17. The building heating can be achieved by relying solely on the water pump drive. The system has low energy consumption, and the method of taking water from the upper floor and returning water to the lower floor does not disturb the water temperature stratification. It can effectively utilize high-grade heat energy and extend the operating cycle of the direct supply condition.

[0075] 4. Water tank heat source heat pump quality improvement and heating operation This operating condition is applicable to the middle and late stages of the heating season, when the water temperature in the water storage chamber drops to the t3-t4 range, and the direct heating requirements cannot be met, but there is still medium-temperature heat energy. At this time, the water tank and buried pipe heat release circulation pump 23, the water source heat pump unit 17, and the water source heat pump secondary side water pump 19 are turned on. Simultaneously, the heat release circulation valve group 24, the water tank heat release valve group 35, the water source heat pump primary side valve group 15, the water source heat pump secondary side valve group 18, the heat pump to the heating network heating valve group 38, the water tank water intake valve group 25 corresponding to the target water storage chamber, the middle tubular water intake on / off valve 40, and the lower tubular water intake on / off valve 41 are turned on, and all other valve groups are turned off. The medium forms two closed-loop circulations. One is the heat source side circulation: target water storage chamber → middle tubular water intake 46 → middle tubular water intake on / off valve 40 → water tank water intake valve group 25 → water tank heat release valve group 35 → heat release circulation valve group 24 → water source heat pump unit 17 evaporator side → target water storage chamber → lower tubular water intake 47 → lower tubular water intake on / off valve 41 → water tank water intake valve group 25; the other is the heating side circulation: water source heat pump unit 17 condenser side → water source heat pump secondary side valve group 18 → water source heat pump secondary side water pump 19 → heat pump to heating network heating valve group 38 → external heating interface 20 → water source heat pump unit 17 condenser side. This operating mode uses the medium-temperature water in the water storage chamber as the heat source of the heat pump, effectively utilizing the solar energy stored across seasons. It solves the problem of traditional systems relying on buried pipe heat sources for heat pump operation throughout the middle and late stages of the heating season, reducing system energy consumption. At the same time, the method of water intake from the middle layer and water return from the lower layer does not disturb the water temperature stratification throughout the process, which can extend the utilization cycle of high-grade heat energy.

[0076] 5. Heat pump reheating operation This operating condition is applicable during the heating season when there are continuous rainy days, the water temperature in the water storage chamber drops to the t3-t4 range, and it is necessary to supplement the heat of the hot water storage tank to maintain its heating capacity. At this time, the water tank and buried pipe heat release circulation pump 23, the water source heat pump unit 17, and the water source heat pump secondary side water pump 19 are turned on. Simultaneously, the heat release circulation valve group 24, the buried pipe heat release valve group 36, the buried pipe valve group 12, the water source heat pump primary side valve group 15, the water source heat pump secondary side valve group 18, the heat pump to water tank supplementation valve group 37, the water tank water intake valve group 25 corresponding to the target water storage chamber, the upper tubular water intake on / off valve 39, and the lower tubular water intake on / off valve 41 are turned on, and all other valve groups are turned off. The medium forms two closed-loop circulations. One is the heat source side circulation: buried pipe 33 → buried pipe valve group 12 → buried pipe heat release valve group 36 → heat release circulation valve group 24 → evaporator side of water source heat pump unit 17 → buried pipe 33; the other is the heat replenishment side circulation: condenser side of water source heat pump unit 17 → secondary side valve group 18 of water source heat pump → secondary side water pump 19 of water source heat pump → heat pump to water tank heat replenishment valve group 37 → water tank water intake valve group 25 → upper tubular water intake on / off valve 39 → upper tubular water intake 45 → target water storage chamber → lower tubular water intake 47 → lower tubular water intake on / off valve 41 → water tank water intake valve group 25 → evaporator side of water source heat pump unit 17. This operating mode uses the low-grade heat reservoir of the underground pipe group as the heat source to supplement and raise the temperature of the hot water storage tank, maintain its heating temperature, and does not disturb the water temperature stratification, thus ensuring the stable operation of the direct supply mode.

[0077] 6. Emergency direct supply operation of buried pipe heat source This operating condition is for system safety assurance and is applicable to extreme low temperatures during the heating season, when the water temperature in the storage chamber drops below t3, or when the hot water storage tank is under maintenance. In this case, the water tank and buried pipe heat release circulation pump 23, the water source heat pump unit 17, and the secondary side water pump 19 of the water source heat pump are turned on. At the same time, the heat release circulation valve group 24, the buried pipe heat release valve group 36, the buried pipe valve group 12, the water source heat pump primary side valve group 15, the water source heat pump secondary side valve group 18, and the heat pump to the heating network heating valve group 38 are turned on, and all other valve groups are turned off. The medium forms two closed-loop circulations: one is the heat source side circulation: buried pipe 33 → buried pipe valve group 12 → buried pipe heat release valve group 36 → heat release circulation valve group 24 → evaporator side of water source heat pump unit 17 → buried pipe 33; the other is the heating side circulation: condenser side of water source heat pump unit 17 → secondary side valve group 18 of water source heat pump → secondary side water pump 19 of water source heat pump → heat pump to heating network heating valve group 38 → external heating interface 20 → condenser side of water source heat pump unit 17. This operating condition is completely isolated from the hot water storage tank, which can ensure the stability and reliability of building heating under extreme conditions and avoid heating interruption.

[0078] This system is equipped with an automated control device. Temperature sensors are installed at the upper tubular water inlet 45, middle tubular water inlet 46, and lower tubular water inlet 47 of each water storage chamber to monitor the water temperature stratification within the chamber in real time. Temperature, pressure, and flow sensors are installed at the inlet and outlet of the photovoltaic-thermal integrated panel array 1, the inlet and outlet of the buried pipe 33, the inlet and outlet of the evaporator and condenser of the water source heat pump unit 17, and the external heating interface 20 to collect system heat exchange and transport parameters in real time. A liquid level sensor is installed in each water storage chamber to achieve real-time monitoring of the water level and water shortage protection. All sensor signals are connected to the automated control device. The control device can collect various system operating data in real time according to preset control logic, automatically switch between six operating conditions, accurately control the on / off state of each electric valve group and the operating frequency of the variable frequency water pump, and automatically select the opening level of the water inlet based on the water temperature stratification data within the water storage chamber, realizing fully automated unattended operation of the system and ensuring that the system is always in an optimal energy efficiency state.

Claims

1. A cross-seasonal heating system, comprising a photovoltaic thermal collector unit, an underground heat storage unit, and an external heat supply interface, wherein the collector side of the photovoltaic thermal collector unit is connected to the underground heat storage unit and serves as an input heat source, and the underground heat storage unit is connected to the external heat supply interface and is used to output heat; characterized in that, The photovoltaic thermal collector unit's power generation end is connected to the energy storage battery and serves as the power source for the system's electrical components. The underground thermal storage unit and the external heating interface are also connected via a control pipeline system to a water source heat pump unit.

2. The interseasonal heating system according to claim 1, characterized in that, The photovoltaic-thermal collector unit includes a core photovoltaic-thermal integrated panel array. Its power generation end is connected to a battery via a charging cable. The battery is equipped with an inverter module, which is connected to each electrical component in the system through a corresponding power supply circuit.

3. The interseasonal heating system according to claim 1, characterized in that, The collector side of the photovoltaic thermal collector unit is connected to the hot side of the collector heat exchanger via a collector hot water circulation pipeline and a collector hot water circulation pump, forming a closed-loop heat collection cycle. The cold side of the collector heat exchanger is connected to the charging circulation pipeline of the control pipeline system and to the underground thermal storage unit. The output end of the charging circulation pipeline is connected to the external heating interface. The charging circulation pipeline is also connected to the evaporator side of the water source heat pump unit. The output end of the water source heat pump unit is connected to the external heating interface.

4. The interseasonal heating system according to claim 3, characterized in that, The underground thermal storage unit includes a high-grade thermal reservoir located in the middle and a low-grade thermal reservoir located in the surrounding area; the high-grade thermal reservoir is a hot water storage tank buried underground, and the low-grade thermal reservoir is a group of buried pipes arranged in a closed loop around the hot water storage tank, and the buried pipe group is buried in the rock and soil around the hot water storage tank.

5. The interseasonal heating system according to claim 4, characterized in that, The hot water storage tank is a regional parallel hot water storage tank, which includes four independent water storage chambers arranged in a grid pattern, divided by an intermediate earthen embankment of the original soil body. The four water storage chambers are arranged in parallel. The water storage chamber adopts a trapezoidal cross-section structure that is wider at the top and narrower at the bottom; The inner wall of the water storage chamber is entirely covered with a high-polymer waterproof and seepage-proof membrane. Each water storage chamber is equipped with a water tank insulated cover.

6. The interseasonal heating system according to claim 5, characterized in that, Each water storage chamber is equipped with a layered water intake assembly, which includes three layers of tubular water intake devices arranged horizontally on the inner wall along the depth of the water storage chamber. The tubular water intake devices have water outlets along their length on the inner side facing the water storage chamber. Both ends of each layer of tubular water intake devices are connected upwards in parallel to the heat charging circulation pipeline of the control pipeline system through dedicated water intake device pipes. Then, they are connected upwards to the parallel water tank direct supply heat exchanger and water source heat pump unit through the water tank heat release pipeline. Each layer of tubular water intake devices is equipped with an independent solenoid valve group on its dedicated water intake device pipes at both ends. The water tank heat release pipeline is sequentially equipped with a water tank heat release valve group, a heat release circulation valve group, and a water tank direct supply operating condition valve group, and is connected to the input end of a water tank direct supply heat release exchanger. The output end of the water tank direct supply heat release exchanger is connected to the external heating interface through a water tank direct supply output pipeline equipped with a water tank direct supply operating condition load side circulation pump. A water tank and buried pipe heat release circulation pump is installed on the water tank heat release pipeline between the heat release circulation valve group and the water tank direct supply operating condition valve group. A heat pump supplementary heating pipeline is also bypassed on the water tank heat release pipeline between the heat release circulation valve group and the water tank direct supply operating condition valve group and is connected to the evaporator side of the water source heat pump unit. A water source heat pump primary side valve group is installed on the heat pump supplementary heating pipeline.

7. The interseasonal heating system according to claim 6, characterized in that, A flow stabilizing device is installed on the outside of the tubular water collector in the middle layer. The flow stabilizing device is a tubular filter bag fixedly sleeved outside the water inlet. The lower surface of the tubular filter bag has openings evenly spaced along its length.

8. The interseasonal heating system according to claim 4, characterized in that, The underground pipe group includes underground pipes buried in the surrounding soil around the hot water storage tank. The underground pipes are arranged in a rectangular circle around the hot water storage tank. The upper ends of each underground pipe are connected to two underground pipe trunks through underground pipe valve groups. The underground pipe trunks are connected to the heat charging circulation pipeline through underground pipe heat charging circulation valve groups. The two underground pipe trunks are also connected by bypass pipes equipped with underground pipe heat release valve groups and connected to the evaporator side of the water source heat pump unit.

9. The interseasonal heating system according to claim 3, characterized in that, The water source heat pump unit obtains power through the water source heat pump power supply circuit. Its evaporator side is switchably connected to the hot water storage tank and the underground pipe group through the primary side valve group of the water source heat pump. The two output pipes connected from its condenser side are sequentially connected to the external heating interface after installing a secondary side valve group of the water source heat pump, a secondary side water pump of the water source heat pump, and a heat pump to the heating network heating valve group. The farthest end of the charging circulation pipeline is equipped with a heat pump to the water tank heat replenishment valve group and then connected to the output pipe between the secondary side valve group of the water source heat pump and the heat pump to the heating network heating valve group.

10. The interseasonal heating system according to claim 9, characterized in that, The control pipeline system includes six independent closed-loop operating branches: a high-grade heat storage circulation branch, a low-grade heat storage circulation branch, a direct heating branch from the hot water storage tank, a heat pump supplementary heating branch, a heat pump quality improvement heating branch from the water tank heat source, and an emergency direct heating branch from the buried pipe heat source. The high-grade thermal storage circulation branch includes the thermal charging circulation pipeline and the thermal charging circulation pump and the water tank thermal charging circulation valve group installed thereon. The water tank thermal charging circulation valve group is located on the thermal charging circulation pipeline between the connection point of the water intake pipe and the connection point of the buried main pipe. The high-grade thermal storage circulation branch also includes each layer of tubular water intake and its dedicated water intake pipes at both ends, as well as the solenoid valve group installed on the water intake pipe. The low-grade heat storage circulation branch includes the heat charging circulation pipeline and the heat charging circulation pump installed thereon, as well as the underground pipe group, the underground pipe valve group, the underground pipe trunk and the underground pipe heat charging circulation valve group installed thereon. The direct heating branch of the hot water storage tank includes a water tank heat release pipeline and its water tank heat release valve group, heat release circulation valve group, water tank and buried pipe heat release circulation pump, water tank direct supply condition valve group and water tank direct supply heat exchanger, as well as the water tank direct supply output pipeline and water tank direct supply condition load side circulation pump at the output end of the water tank direct supply heat exchanger and the external heating interface. The heat pump supplementary heating branch includes the heat pump supplementary heating pipeline and the water source heat pump primary side valve group and water source heat pump unit on it. The water tank heat source heat pump quality improvement and heating branch includes the water tank and buried pipe heat release circulation pump, heat release circulation valve group, water tank heat release valve group, water source heat pump unit and heat pump to heat network heating valve group, as well as their respective corresponding pipelines and external heating interfaces. The underground pipe heat source emergency direct supply branch includes a water tank and underground pipe heat release circulation pump, heat release circulation valve group, underground pipe heat release valve group, water source heat pump unit, heat pump to heat network heating valve group and their corresponding pipelines, as well as external heating connection.

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