A multi-source composite, cross-seasonal high-efficiency thermal storage heat pump system and its control method

Abstract

This invention relates to the field of low-carbon and low-energy building design technology, specifically to a multi-source composite, cross-seasonal, high-efficiency thermal storage heat pump system and its control method. The system includes a heat replenishment tower system, an underground composite thermal storage system, a soil-source heat pump unit, a phase change hot water storage tank, a gas-water heat exchanger, and a PVT photovoltaic-thermal integrated system. This system efficiently utilizes multiple "free" heat sources in summer. The PVT photovoltaic-thermal integrated system generates electricity and provides domestic hot water while fully utilizing the high-temperature "waste heat" behind the PVT curtain wall in summer. The heat replenishment tower system absorbs heat from the ambient air and the latent heat of condensation of water vapor in the atmosphere through filler material, while also utilizing solar radiation heat exchange. This heat is stored through the upgraded underground composite thermal storage system. While providing a large heat load to meet the building's heating needs in winter, this system further avoids problems such as large heat loss and a single heat storage method.

Description

Technical Field

[0001] This invention relates to the field of low-carbon and low-energy building design technology, specifically to a multi-source composite cross-seasonal high-efficiency thermal storage heat pump system and its control method. Background Technology

[0002] Energy is the foundation of economic and social development. Excessive use of fossil fuels leads to climate change, energy crises, and environmental pollution. Reducing energy consumption and cutting fossil fuel use are key strategies for addressing these problems. Renewable energy offers advantages such as being green, energy-efficient, and having zero carbon emissions, and its development and utilization are receiving increasing attention. Geothermal energy is one of the clean heating methods, boasting advantages such as wide resource distribution, clean and low-carbon operation, and stability and reliability. Its application technology is relatively mature, making it highly suitable for installation in new buildings, industrial parks, and urban areas.

[0003] Shallow ground source heat pump systems, based on the relatively constant ground temperature below the surface, simultaneously cool or heat buildings while releasing heat into the soil in summer and extracting heat from the soil in winter. In severely cold and frigid regions of my country, ground source heat pumps are primarily used for winter heating, where the heating period and heat load intensity are far greater than the summer air-conditioning period. This results in the ground source heat pump extracting more heat from the soil in winter than releasing it in summer during the system's operating cycle. Over the long term, this imbalance between heat extraction and release leads to a gradual decrease in soil temperature around the buried pipes, resulting in "cold accumulation" in the soil. Consequently, the operating efficiency of the ground source heat pump unit declines year by year, eventually causing the system to fail and be unable to start normally. This invention aims to address the problem of continuously decreasing soil temperature by storing waste heat and other heat energy that cannot be absorbed during the peak solar season in summer, allowing it to be utilized in winter when needed, thus meeting indoor heating demands.

[0004] Chinese invention patent application CN114623489A discloses an application method for a solar-soil composite heat pump cross-seasonal energy storage system. The cross-seasonal energy storage system includes a controller, a solar collector, a buried pipe heat exchanger, a heat pump unit, a soil and rock thermal property testing device, a circulating water pump, and an intermediate heat exchanger. The heat collected by the solar collector is indirectly transferred to the buried pipe heat exchanger through the heat pump unit and the intermediate heat exchanger, and the solar thermal energy is stored in the underground soil. The circulating pump connects the soil and rock thermal property testing device with the buried pipe heat exchanger to test soil data. Through the solar-soil composite heat pump cross-seasonal energy storage system, the required solar collector area and buried pipe parameters are calculated by combining the solar collector and the buried pipe heat exchanger with soil and rock thermal property testing. This solves the soil temperature imbalance problem caused by the soil source heat pump system and realizes cross-seasonal heat storage and heating needs.

[0005] Chinese invention patent application CN112413765A discloses a method and system for cross-seasonal energy storage cooling and heating in a near-zero energy community. The system includes a ground source heat pump system, a buried pipe soil heat exchanger, a heat pump unit, and a solar thermal collector system. In summer, the ground source heat pump system is used to meet the building's cooling needs; in winter, the ground source heat pump system is used to meet the building's heating needs; and in the transitional season, the solar thermal collector system is used to collect heat and the ground source heat pump system is used to transfer the heat into the soil.

[0006] However, in many buildings in frigid and cold regions, the heat load of shallow soil source heat pump systems is much greater than the cooling load, causing the heat pump to absorb more heat from the soil than it releases. Over time, this leads to a continuous decrease in soil temperature, reduced unit efficiency, and even inoperability. Solar energy is limited by weather, region, and season, exhibiting intermittent and unstable characteristics, resulting in a mismatch between supply and demand. Furthermore, it is not easy to store and must be converted into other forms of energy in a timely manner to be effectively utilized when needed. Cross-seasonal heat storage is an effective method to solve the above problems and an effective means to expand the depth and breadth of renewable energy thermal energy utilization. Summary of the Invention

[0007] To address the problem of low heat storage and utilization efficiency in existing cross-seasonal heat storage systems, this invention provides a multi-source composite cross-seasonal high-efficiency heat storage heat pump system and its control method.

[0008] This invention is achieved through the following technical solution:

[0009] A multi-source composite cross-seasonal high-efficiency heat storage heat pump system includes a heat replenishment tower system, an underground composite heat storage system, a soil source heat pump unit, a phase change hot water storage tank, a gas-water heat exchanger, and a PVT photovoltaic-thermal integrated system. The PVT curtain wall of the PVT photovoltaic-thermal integrated system is set on the outer wall of the building, and a cavity is formed between the PVT curtain wall and the wall. The cavity is bidirectionally connected to the air side of the gas-water heat exchanger.

[0010] The air supply duct between the cavity's exhaust port and the air-side hot air inlet L1 of the air-water heat exchanger is connected to a fifth valve V5 and a blower. The air-side cold air outlet L2 of the air-water heat exchanger is connected to the cavity's air supply port through the exhaust duct.

[0011] The air conditioning return water pipe LHH of the soil source heat pump unit is connected to the return water inlet of the building through the first hot water circulation pump and the fourth valve V4 in sequence, and the air conditioning supply water pipe LHG of the soil source heat pump unit is connected to the water supply inlet of the building through the third valve V3.

[0012] The first inlet L3 of the phase change hot water storage tank is connected to the return outlet of the building through the second hot water circulation pump and the first valve V1 in sequence, and the first outlet L4 of the phase change hot water storage tank is connected to the supply outlet of the building through the second valve V2.

[0013] The eighth valve V8 is connected to the phase change heat storage water supply pipeline between the second inlet L5 of the phase change heat storage tank and the hot water outlet L9 of the gas-water heat exchanger. The ninth valve V9 and the phase change cold water circulation pump are connected to the pipeline between the second outlet L6 of the phase change heat storage tank and the cold water inlet L10 of the gas-water heat exchanger.

[0014] The ground source heat pump unit’s ground source side outlet L8 is connected to the heat replenishment tower system’s heat replenishment inlet L12 through the eleventh valve V11. The ground source side inlet L7 of the ground source heat pump unit is connected to the outlet of the underground composite heat storage system through the fourteenth valve V14, the geothermal side circulation pump and the fifteenth valve V15 in sequence.

[0015] The hot water outlet L9 of the gas-water heat exchanger is connected to the inlet of the underground composite thermal storage system through the sixth valve V6 and the heat replenishment outlet L11 of the heat replenishment tower system. The cold water inlet L10 of the gas-water heat exchanger is connected to the underground composite thermal storage system through the seventh valve V7, the geothermal side circulation pump and the fifteenth valve V15.

[0016] The heat replenishment outlet L11 of the heat replenishment tower system is connected to the inlet of the underground composite heat storage system through the tenth valve V10 and the thirteenth valve V13.

[0017] A twelfth valve V12 is installed on the bypass pipe between the heat supply outlet L11 and the heat supply inlet L12 of the heat supply tower system.

[0018] Preferably, the exhaust vent is located in the upper part of the cavity, and the air supply vent is located in the lower part of the cavity. The exhaust vent and the air supply vent are arranged diagonally, and the number of exhaust vents is greater than the number of air supply vents.

[0019] Preferably, the heat replenishment tower system includes a tower body, a variable frequency fan, and a water replenisher. The water inlet of the water replenisher is connected to the heat replenishment water inlet L12 of the heat replenishment tower system. The variable frequency fan is installed on the top inside the tower body. The middle part of the tower body adopts a light-transmitting structure. The inner side of the middle part of the tower body is filled with packing material. The water outlet of the water replenisher faces the packing material. A heat replenishment water outlet L11 is provided at the bottom of the tower body.

[0020] Preferably, the packing is made of multi-layer corrugated plates.

[0021] Preferably, the underground composite thermal storage system is composed of a water tank thermal storage system and a buried pipe thermal storage system coupled together. The underground water tank of the water tank thermal storage system is located in the center of the underground composite thermal storage system, and the buried pipes of the buried pipe thermal storage system are arranged around the underground water tank.

[0022] Preferably, in the total volume of the underground composite thermal storage system, the volume ratio of the underground water tank and the buried pipe is no higher than 1:2; the mass flow rate of the underground water tank and the buried pipe each accounts for half of the total mass flow rate.

[0023] Preferably, the underground water tank is cylindrical, and the buried pipes are arranged in multiple rings around the circumference of the underground water tank, with the distance between two adjacent layers of buried pipes being 1.5~2m.

[0024] Preferably, the buried pipes in adjacent layers are staggered, with the buried pipes in odd-numbered layers on the same diameter line and the buried pipes in even-numbered layers on the same diameter line.

[0025] Preferably, the phase change hot water tank adopts a solid-liquid phase change energy storage tank, including a packaging container and a phase change material. The phase change material is filled in the packaging container. The phase change material is arranged in a plate-like manner with cylindrical tube bundles and parallel staggered arrangement. The phase change temperature of the phase change material is higher than the temperature of the air conditioning water required by the building.

[0026] A control method for a multi-source, composite, cross-seasonal high-efficiency thermal storage heat pump system, wherein the control system outputs signals to change the state of corresponding valves at different times to achieve different heat outputs, specifically:

[0027] During summer cooling, the ground source heat pump unit starts up, opening valves V3 and V4 to supply chilled water into the building through the air conditioning supply pipe LHG on the unit's air conditioning side. After cooling at the indoor air conditioning terminals, the high-temperature chilled water returns to the ground source heat pump unit through the air conditioning return pipe LHH. At this time, valves V1, V2, V8, V9, and V12 are closed, while the remaining valves are open. The first hot water circulation pump and the geothermal side circulation pump are turned on, while the phase change chilled water circulation pump and the second hot water circulation pump are turned off, and the blower is in operation.

[0028] During summer heat storage, the ground source heat pump unit starts up and opens the eleventh valve V11. The low-temperature hot water that absorbs the indoor waste heat is transported to the heat exchange tower system through the first pipeline on the ground source side of the unit. At this time, the twelfth valve V12 on the bypass pipe between the heat exchange outlet L11 and the heat exchange inlet L12 of the heat exchange tower system is closed. After the heat exchange tower system absorbs heat and heats up, the tenth valve V10 and the thirteenth valve V13 are opened. The high-temperature hot water is transported to the underground composite heat storage system through the heat exchange water supply pipeline for heat exchange. The low-temperature cold water after heat exchange is returned to the ground source heat pump unit through the fifteenth valve V15 and the geothermal side circulation pump through the second pipeline on the ground source side.

[0029] During summer heat storage, the fifth valve V5 and the blower are opened. The waste heat generated by the PVT curtain wall in the PVT photovoltaic-thermal integrated system is used as another high-temperature heat source to heat the air in the cavity. The heated air is delivered to the air side of the air-water heat exchanger through the blower via the air supply duct. The low-temperature air after heat exchange is returned to the cavity through the exhaust duct. At this time, the eighth valve V8 and the ninth valve V9 are closed.

[0030] During summer heat storage, on the water side of the gas-water heat exchanger, the sixth valve V6 is opened. After heat exchange with hot air, the high-temperature hot water mixes with the hot water heated by the heat replenishment tower system and is collectively sent to the underground composite heat storage system. After heat storage in the underground composite heat storage system, a low-temperature fluid is formed and enters the geothermal side circulation pump. Then, part of the low-temperature fluid returns to the water side of the gas-water heat exchanger through the seventh valve V7 and the cold water inlet L10, while the other part of the low-temperature fluid returns to the ground source side inlet L7 of the ground source heat pump unit through the fourteenth valve V14.

[0031] During the daytime heating season in winter, the ground source heat pump unit extracts heat from the underground composite thermal storage system on the ground source side: the fifteenth valve V15, the geothermal side circulation pump and the fourteenth valve V14 are opened, and the eleventh valve V11 is closed. The high-temperature hot water enters the ground source heat pump unit through the ground source side inlet L7 via the second pipeline on the ground source side for heat exchange. The low-temperature fluid after heat exchange enters the first pipeline on the ground source side from the ground source side outlet L8 of the ground source heat pump unit, and then returns to the underground composite thermal storage system through the twelfth valve V12 and the thirteenth valve V13 opened on the bypass pipeline. The fluid does not pass through the heat replenishment tower system.

[0032] During daytime heat storage in winter, the gas-water heat exchanger exchanges heat on both sides. The high-temperature hot water on the water side of the gas-water heat exchanger is transported to the phase change heat storage tank through the open eighth valve V8 and the phase change heat storage water supply pipeline. After heat storage in the phase change heat storage tank, the phase change cold water circulation pump and the ninth valve V9 are turned on, and the low-temperature fluid returns to the water side of the gas-water heat exchanger through the phase change heat storage return water pipeline. At this time, the first valve V1 and the second valve V2 on the other side of the phase change heat storage tank 4 are closed, and the sixth valve V6, the seventh valve V7, the tenth valve V10, and the eleventh valve V11 are also closed. The first hot water circulation pump and the phase change cold water circulation pump are turned on, the second hot water circulation pump is turned off, and the blower is in operation.

[0033] During winter nights, the duty temperature is maintained at 5℃ for heating. The ground source heat pump unit is stopped from operation. The third valve V3, the fourth valve V4, the first hot water circulation pump 9, and the fourteenth valve V14 on the second pipeline on the ground source side of the air conditioning water supply pipe LHG of the ground source heat pump unit are closed. The second hot water circulation pump, the first valve V1, and the second valve V2 are opened to supply heat to the air conditioning terminals in the building from the phase change hot water storage tank.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] This invention discloses a multi-source composite, cross-seasonal, high-efficiency thermal storage heat pump system that efficiently utilizes multiple "free" heat sources in summer and stores them through the upgrading and transformation of an underground composite thermal storage system. In summer, a soil-source heat pump unit provides cooling to the building and discharges indoor waste heat to the underground composite thermal storage system via pipelines. Simultaneously, the PVT photovoltaic-thermal integrated system generates electricity and provides domestic hot water while fully utilizing the high-temperature "waste heat" behind the PVT curtain wall of the photovoltaic-thermal integrated system in summer. This "waste heat" is recovered by a wind system and stored in the underground composite thermal storage system, which can reduce the temperature of the PVT curtain wall in the photovoltaic-thermal integrated system, thereby improving the overall power generation efficiency of the photovoltaic system. Furthermore, because buildings in severely cold and cold regions require a large heat load in winter, a heat recovery tower system can transfer the summer-stored heat to the underground composite thermal storage system, enabling soil temperature recovery.

[0036] The heat replenishment tower system absorbs heat from the ambient air and the latent heat of condensation of water vapor in the atmosphere through packing material, while utilizing solar radiation heat exchange, thereby maximizing the heat replenishment capacity of the underground composite heat storage system.

[0037] The underground composite thermal storage system combines hot water thermal storage and buried pipe thermal storage. It is a new type of cross-seasonal composite thermal storage system that combines two thermal storage methods. This underground composite thermal storage system takes advantage of its strengths and avoids its weaknesses, which can effectively reduce the footprint, reduce the use of insulation materials, and make the thermal storage / release mechanism more flexible and versatile.

[0038] Ground source heat pump units utilize underground composite heat storage systems to store a certain amount of heat in the summer. This not only greatly improves the system's operating efficiency during winter use, but also continuously provides the building with the necessary heating source while reducing system energy consumption. In early winter, late winter, or during sunny winter days, the system can continue to utilize the multi-source heat source system to store heat in the phase change hot water storage tank, continuing to play a role in the winter season. This reduces the operating time of the heat pump unit, thereby reducing operating costs. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a multi-source composite cross-seasonal high-efficiency heat storage heat pump system according to the present invention.

[0040] Figure 2 This is a structural diagram of the heat replenishment tower in a multi-source composite cross-seasonal high-efficiency thermal storage heat pump system of the present invention;

[0041] Figure 3 This is a plan view of the underground composite thermal storage system in a multi-source composite cross-seasonal high-efficiency thermal storage heat pump system of the present invention.

[0042] Figure 4This is a schematic diagram of the phase change material arrangement in the phase change water storage tank of a multi-source composite cross-seasonal high-efficiency thermal storage heat pump system of the present invention.

[0043] In the diagram, 1. Heat replenishment tower system; 101. Variable frequency fan; 102. Water replenisher; 103. Packing material; 104. Transparent structure; 105. Tower body; 106. Water replenishment inlet pipe; 107. Water replenishment outlet pipe; 2. Underground composite heat storage system; 201. Underground water tank; 202. Buried pipe; 3. Soil source heat pump unit; 4. Phase change heat storage tank; 5. Gas-water heat exchanger; 501. Water side; 502. Air side; 6. Building structure; 7. 1. PVT photovoltaic-thermal integrated system; 8. Blower; 9. First hot water circulation pump; 10. Geothermal side circulation pump; 11. Phase change cold water circulation pump; 12. Second hot water circulation pump; 13. Air supply duct; 14. Exhaust duct; 15. First geothermal side duct; 16. Second geothermal side duct; 17. Bypass pipe; 18. Heat supply water duct; 19. Phase change thermal storage water supply duct; 20. Phase change thermal storage return water duct; 21. Phase change material; L1. L1, Hot air inlet on air side; L2, Cold air outlet on air side; L3, First water inlet; L4, First water outlet; L5, Second water inlet; L6, Second water outlet; L7, Ground source water inlet; L8, Ground source water outlet; L9, Hot water outlet; L10, Cold water inlet; L11, Heat replenishment outlet; L12, Heat replenishment inlet; L13, First heat replenishment air inlet; L14, Second heat replenishment air inlet; L15, Heat replenishment air outlet. V1, First valve; V2, Second valve; V3, Third valve; V4, Fourth valve; V5, Fifth valve; V6, Sixth valve; V7, Seventh valve; V8, Eighth valve; V9, Ninth valve; V10, Tenth valve; V11, Eleventh valve; V12, Twelfth valve; V13, Thirteenth valve; V14, Fourteenth valve; V15, Fifteenth valve; LHG, Air conditioning supply water pipe; LHH, Air conditioning return water pipe. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0045] This invention discloses a multi-source composite, cross-seasonal, high-efficiency heat storage heat pump system, referring to... Figure 1 It includes a heat replenishment tower system 1, an underground composite heat storage system 2, a soil source heat pump unit 3, a phase change hot water storage tank 4, a gas-water heat exchanger 5, and a PVT photovoltaic-thermal integrated system 7. The PVT curtain wall of the PVT photovoltaic-thermal integrated system 7 is set on the outer wall of the building 6, and a cavity is formed between the PVT curtain wall and the wall. The cavity is bidirectionally connected to the air side 502 of the gas-water heat exchanger 5.

[0046] A fifth valve V5 and a blower 8 are connected to the air supply pipe 13 between the air outlet of the cavity and the air-side hot air inlet L1 of the air-water heat exchanger 5. The air-side cold air outlet L2 of the air-water heat exchanger 5 is connected to the air outlet of the cavity through the air supply pipe 14.

[0047] The PVT (Photovoltaic-Thermal Integrated System) 7's PVT modules are installed on the outer surface of the building's external envelope, enabling it to provide both electricity and heat. This solves the cooling problem of the photovoltaic modules and improves the heat gain of the building's external envelope. The cavity formed between the PVT curtain wall and the outer wall heats the air inside during the summer daytime using solar radiation. The high-temperature air is then delivered to the air-to-water heat exchanger 5 via the air supply duct 13 and a fan connected to the cavity. The extracted heat from the high-temperature air heats the water side of the air-to-water heat exchanger 5. The heated water is then transferred to the underground composite thermal storage system 2 via the sixth valve V6 and the thirteenth valve V13. The stored heat serves as one of the heat sources for winter heating.

[0048] In one embodiment, the cavity thickness is 80-100mm. The air supply outlet is located at the lower part of the cavity and connected to the exhaust duct 14 (low-temperature air after heat exchange). The upper part of the cavity has an exhaust outlet connected to the air supply duct 13 (high-temperature air after heating). The air supply duct 13 is equipped with a wind speed sensor and a temperature sensor to monitor the wind speed and temperature in real time. The exhaust outlet and the air supply outlet are arranged diagonally in the cavity, and the wind speed of the air supply outlet is 4-6m / s, and the wind speed of the exhaust outlet is 3-4m / s. All air outlets are square. The number of exhaust outlets is greater than that of the air supply outlets. The exhaust outlets are evenly distributed, and the center distance between the first exhaust outlet and the last exhaust outlet is not greater than half the total length of the PVT curtain wall.

[0049] The PVT photovoltaic-thermal integrated system 7 combines photovoltaic cells (or modules) with solar collectors using lamination or adhesive technology. While performing solar photovoltaic conversion, it also collects the "waste heat" generated during solar power generation for secondary utilization, which can be stored in summer. After being integrated with the outer wall of the building 6, the PVT photovoltaic-thermal integrated system 7 significantly reduces construction costs and floor space compared to a simple photovoltaic power generation system. It also reduces building energy consumption, and the generated electricity can be used locally, minimizing transmission losses. Research shows that for every 1°C increase in the surface temperature of a photovoltaic cell, its power generation efficiency decreases by approximately 0.5%. The PVT photovoltaic-thermal integrated system 7 cools the solar photovoltaic panels while reducing the backsheet air temperature, thereby improving solar photovoltaic power generation efficiency, extending service life, and increasing the overall utilization rate of solar energy. It not only enables cross-seasonal heat storage in summer but also allows for continued use in winter. Heat can be stored in a phase change energy storage tank for short periods, significantly extending the utilization time of renewable energy.

[0050] Reference Figure 2 The heat exchange tower system 1 includes a tower body 105, a variable frequency fan 101, and a water supply unit 102. The variable frequency fan 101 is installed on the top of the inner side of the tower body 105. The water inlet of the water supply unit 102 is connected to the heat exchange water inlet L12 on the tower body 105 via a water supply pipe 106. The middle part of the tower body 105 is surrounded by a light-transmitting structure 104. Part of the solar energy absorbed by the light-transmitting structure 104 is dissipated to the environment through convection, and part of it is transferred to the black packing material 103 through heat conduction. Heat is also transferred between the light-transmitting structure 104 and the packing material 103 through radiation. The light-transmitting structure 104 raises the air temperature inside the heat exchange tower and heats the black packing material 103, ultimately increasing the heat exchange capacity of the circulating water in the heat exchange tower.

[0051] In one embodiment, the light-transmitting material of the heat exchange tower is a transparent PVC flexible sheet with a heat transfer coefficient of 5.8 W / (m²). 2 (·K). The inlet water temperature has the greatest impact on the outlet water temperature of the heat storage tower. In order to increase the soil temperature rise after heat storage, it is necessary to maximize the inlet water temperature of the heat storage tower. Therefore, a heat pump unit is selected to provide cooling in summer. The heat storage tower system 1 is connected in series between the heat pump unit and the underground composite heat storage system 2. The outlet water of the heat storage system enters the heat pump unit, is heated by the cooling cycle, and then introduced into the heat storage tower as inlet water. The temperature is further increased, and the water flows out of the heat storage tower and into the underground composite heat storage system 2 to store heat.

[0052] The inner side of the middle part of the tower body 105 is equipped with packing 103, and the outlet of the water supply device 102 faces the packing 103. The packing 103 is made of multi-layer corrugated plate and polybutene material. When used continuously for a long time, the upper limit of the temperature that the packing 103 can withstand can reach 95℃.

[0053] A water supply outlet pipe 107 is installed at the bottom of the tower body 105, which is connected to the heat supply outlet L11 at the bottom of the tower body 105. The heat supply tower system 1 introduces circulating water from the water supply inlet pipe 106, which is then evenly sprayed onto the concave-convex packing layer 103 via the water supply device 102. The circulating water forms a liquid film on the surface of the packing 103, while air flows counter-currently through the spatial surface gaps formed by the multi-layer corrugated packing 103, creating a liquid-air contact surface. In summer, through convective heat exchange between the circulating water and air, relying on the surface liquid film, not only sensible heat exchange occurs but also latent heat is absorbed. Furthermore, it fully utilizes solar radiation heat exchange, increasing the heat transfer to the working medium, thereby maximizing the heat storage capacity of the underground composite heat storage system 2. This serves as another type of cross-seasonal heat storage source.

[0054] The tower body 105 has a supplementary heating air outlet L15 at the top and a first supplementary heating air inlet L13 and a second supplementary heating air inlet L14 symmetrically arranged at the bottom. Hot air enters the tower body 105 from the first supplementary heating air inlet L13 and the second supplementary heating air inlet L14, flows in the opposite direction to the circulating spray water, and fully exchanges heat. Then it is discharged from the supplementary heating air outlet L15 at the top of the tower body.

[0055] As another heat source for cross-seasonal heat storage, the supplementary heat tower system 1 is a combination of air energy and solar energy, two renewable energy sources, and an effective and sufficient supplement to underground heat storage. The series connection between the ground source side of the soil source heat pump unit 3 and the underground composite heat storage system 2 can greatly improve the heat storage temperature and heat storage quality.

[0056] The underground composite thermal storage system 2 is a cross-seasonal composite thermal storage system that couples a water tank thermal storage system and a buried pipe thermal storage system. This underground composite thermal storage system 2 is connected to the soil source heat pump unit 3 via a pipeline system. The underground water tank 201 of the water tank thermal storage system is located in the center of the underground composite thermal storage system 2, and the buried pipes 202 of the buried pipe thermal storage system are arranged around the underground water tank 201. For details, refer to... Figure 3 The water tank thermal storage system includes a cylindrical underground water tank 201, which is located at the center of the underground composite thermal storage system 2. The buried pipe thermal storage system includes multiple layers of U-shaped buried pipes 202, which are arranged around the underground water tank 201, and each layer of buried pipes 202 is evenly distributed on the circumference at equal intervals from the underground water tank 201.

[0057] In the total volume of the underground composite thermal storage system 2, the volume ratio of the underground water tank 201 to the buried pipe 202 is no higher than 1:2. Because the system efficiency increases with the increase in the total mass flow rate of heat storage / release, the mass flow rates of the underground water tank 201 and the buried pipe 202 each account for half of the total mass flow rate.

[0058] Limiting the distance between the buried pipe 202 and the underground water tank 201 is to better facilitate the recovery of heat dissipation from the water tank. While meeting design heat load requirements and investment constraints, maximizing the number of buried pipes 202 is beneficial for increasing heat storage / release and improving system efficiency. In one embodiment, the distance between two adjacent layers of buried pipes 202 is 1.5~2m, and adjacent layers of buried pipes 202 are staggered. Odd-numbered layers of buried pipes 202 are on the same diameter line, and even-numbered layers are on the same diameter line. Project sites should preferably be selected in areas with relatively low soil thermal conductivity, which is more beneficial to the system efficiency of underground composite heat storage.

[0059] The underground composite thermal storage system 2 leverages the strengths and avoids the weaknesses of both simple hot water thermal storage and buried pipe thermal storage, while circumventing their unique problems. Unlike hot water thermal storage systems, it avoids high initial investment costs and significant heat loss; unlike buried pipe systems, it doesn't require large storage volumes or have slow storage / release rates. It can combine short-term and cross-seasonal thermal storage. The buried pipe 202 absorbs and inhibits heat diffusion from the underground water tank 201, while reducing the footprint and significantly decreasing the amount of insulation material used, thus lowering costs. Combined with valve control, it enables a flexible and adaptable storage / release mechanism, improving the response speed to changes in building heat load demand.

[0060] The phase change hot water storage tank 4 is a solid-liquid phase change energy storage tank, including a packaging container and a phase change material 21. The phase change material 21 is filled in the packaging container, and the phase change temperature of the phase change material 21 is higher than the temperature of the air conditioning water required by the building 6. In one embodiment, the solid-liquid phase change energy storage tank used in the phase change hot water storage tank 4 is a dual-channel phase change energy storage device, which adopts an overall packaging method, which not only simplifies the processing structure of the device, but also helps to reduce the overall processing cost. The metal packaging container is made by welding, and the packaging material is PET. At the same time, a filling port for the phase change material 21 is reserved at the top of the packaging container. The liquid phase change material is added to the container through the reserved filling port. The phase change material 21 can also be commercial paraffin wax, which is relatively inexpensive and readily available, and has good chemical stability.

[0061] Reference Figure 4 The phase change material 21 is arranged in a cylindrical tube bundle in a plate-like, staggered configuration, causing the heat transfer fluid to flow in an S-shape. This increases the contact area between the heat transfer fluid and the phase change material 21, while also enhancing turbulence during flow, thereby improving the convective heat transfer coefficient and further promoting the energy exchange process between the hot water and the phase change energy storage unit, significantly increasing the heat storage / release rate. Simultaneously, it assists the entire heat pump heating system in achieving short-term heat storage in winter, further maximizing the utilization of renewable energy during winter, reducing the operating time of the heat pump unit, and thus reducing operating costs.

[0062] It also includes pipelines, pump sets, valves and control systems that connect the various units and control the status of the valves, as follows: The air supply pipe 13 between the air outlet of the cavity and the air-side hot air inlet L1 of the air-water heat exchanger 5 is connected to the fifth valve V5 and the blower 8. The air-side cold air outlet L2 of the air-water heat exchanger 5 is connected to the air outlet of the cavity through the air supply pipe 14.

[0063] The air conditioning return water pipe LHH of the soil source heat pump unit 3 is connected to the return water inlet of the building through the first hot water circulation pump 9 and the fourth valve V4 in sequence, and the air conditioning supply water pipe LHG of the soil source heat pump unit 3 is connected to the water supply inlet of the building through the third valve V3.

[0064] The first inlet L3 of the phase change hot water storage tank 4 is connected to the return water outlet of the building through the second hot water circulation pump 12 and the first valve V1 in sequence, and the first outlet L4 of the phase change hot water storage tank 4 is connected to the water supply outlet of the building through the second valve V2.

[0065] An eighth valve V8 is connected to the phase change heat storage water supply pipe 19 between the second inlet L5 of the phase change heat storage tank 4 and the hot water outlet L9 of the gas-water heat exchanger 5. A ninth valve V9 and a phase change cold water circulation pump 11 are connected to the phase change heat storage return water pipe 20 between the second outlet L6 of the phase change heat storage tank 4 and the cold water inlet L10 of the gas-water heat exchanger 5.

[0066] The ground source side outlet L8 of the soil source heat pump unit 3 is connected to the heat replenishment inlet L12 of the heat replenishment tower system 1 through the eleventh valve V11. The ground source side inlet L7 of the soil source heat pump unit 3 is connected to the outlet of the underground composite heat storage system 2 through the fourteenth valve V14, the geothermal side circulation pump and the fifteenth valve V15.

[0067] The hot water outlet L9 of the gas-water heat exchanger 5 is connected to the inlet of the underground composite heat storage system 2 through the sixth valve V6 and the heat supply outlet L11 of the heat supply tower system 1. The cold water inlet L10 of the gas-water heat exchanger 5 is connected to the underground composite heat storage system 2 through the seventh valve V7, the geothermal side circulation pump 10 and the fifteenth valve V15.

[0068] The heat replenishment outlet L11 of the heat replenishment tower system 1 is connected to the inlet of the underground composite heat storage system 2 through the tenth valve V10 and the thirteenth valve V13;

[0069] A twelfth valve V12 is installed on the bypass pipe 17 between the eleventh valve V11 at the heat replenishment outlet L11 and the heat replenishment inlet L12 of the heat replenishment tower system 1. One end of the bypass pipe 17 is connected to the pipe on the inlet side of the eleventh valve V11, and the other end is connected to the pipe on the outlet side of the tenth valve V10.

[0070] This invention also discloses a control method for a multi-source composite, cross-seasonal, high-efficiency thermal storage heat pump system. At different time periods, the control system outputs signals to change the corresponding valve states to achieve different heat outputs. Specifically:

[0071] During summer cooling, the soil source heat pump unit 3 starts up, opening the third valve V3 and the fourth valve V4, and supplying chilled water to the building 6 through the air conditioning water supply pipe LHG on the air conditioning side of the unit. After cooling by the indoor air conditioning terminals, the high-temperature chilled water returns to the soil source heat pump unit 3 through the air conditioning return water pipe LHH. At this time, the first valve V1, the second valve V2, the eighth valve V8, the ninth valve V9, and the twelfth valve V12 are closed, and all other valves are open. The first hot water circulation pump 9 and the geothermal side circulation pump 10 are turned on, the phase change chilled water circulation pump 11 and the second hot water circulation pump 12 are turned off, and the blower 8 is in operation.

[0072] During summer heat storage, the soil source heat pump unit 3 starts up and opens the eleventh valve V11. The low-temperature hot water that absorbs the indoor waste heat is transported to the heat replenishment tower system 1 through the first pipeline 15 on the ground source side of the unit. At this time, the twelfth valve V12 on the bypass pipe 17 between the heat replenishment outlet L11 and the heat replenishment inlet L12 of the heat replenishment tower system 1 is closed. After the heat replenishment tower system 1 absorbs heat and rises in temperature, the tenth valve V10 and the thirteenth valve V13 are opened. The high-temperature hot water is transported to the underground composite heat storage system 2 through the heat replenishment water supply pipeline 18 for heat exchange. The low-temperature cold water after heat exchange is returned to the soil source heat pump unit 3 through the fifteenth valve V15 and the geothermal side circulation pump 10 via the second pipeline 16 on the ground source side.

[0073] During summer heat storage, the fifth valve V5 and the blower 8 are opened. The waste heat generated by the PVT curtain wall in the PVT photovoltaic-thermal integrated system 7 is used as another high-temperature heat source to heat the air in the cavity. The heated air enters the air supply duct 13 through the exhaust port, and is then transported by the blower 8 to the air side 502 of the air-water heat exchanger 5. The low-temperature air after heat exchange returns to the cavity through the exhaust port through the exhaust duct 14. At this time, the eighth valve V8 and the ninth valve V9 are in the closed state.

[0074] During summer heat storage, the sixth valve V6 is opened on the water side 501 of the gas-water heat exchanger 5. After heat exchange with hot air, the high-temperature hot water mixes with the hot water heated by the heat tower system 1 and is collectively sent to the underground composite heat storage system 2. After heat storage in the underground composite heat storage system 2, a low-temperature fluid is formed and enters the geothermal side circulation pump 10. Then, part of the low-temperature fluid returns to the water side 501 of the gas-water heat exchanger 5 through the cold water inlet L10 via the seventh valve V7, and the other part of the low-temperature fluid returns to the ground source side inlet L7 of the soil source heat pump unit 3 through the fourteenth valve V14.

[0075] During the daytime heating season in winter, the ground source heat pump unit 3 extracts heat from the underground composite heat storage system 2 on the ground source side: the fifteenth valve V15, the geothermal side circulation pump 10 and the fourteenth valve V14 are opened, and the eleventh valve V11 is closed. The high-temperature hot water enters the ground source heat pump unit 3 from the ground source side inlet L7 through the second pipeline 16 on the ground source side for heat exchange. The low-temperature fluid after heat exchange enters the first pipeline 15 on the ground source side from the ground source side outlet L8 of the ground source heat pump unit 3, and then returns to the underground composite heat storage system 2 through the twelfth valve V12 and the thirteenth valve V13 opened on the bypass pipe 17. The fluid does not pass through the heat replenishment tower system 1.

[0076] During winter daytime heat storage, the gas-water heat exchanger 5 exchanges heat on both sides, and the high-temperature hot water on the water side 501 of the gas-water heat exchanger 5 is transported to the phase change heat storage tank 4 through the phase change heat storage water supply pipeline 19 via the opened eighth valve V8. After heat storage in the phase change heat storage tank 4, the phase change cold water circulation pump 11 and the ninth valve V9 are opened, and the low-temperature fluid returns to the water side 501 of the gas-water heat exchanger 5 via the phase change heat storage return water pipeline 20. At this time, the first valve V1 and the second valve V2 on the other side of the phase change heat storage tank 4 are closed, and the sixth valve V6, the seventh valve V7, the tenth valve V10 and the eleventh valve V11 are also closed. The first hot water circulation pump 9 and the phase change cold water circulation pump 11 are opened, the second hot water circulation pump 12 is closed, and the blower 8 is in operation.

[0077] During winter nights, the duty temperature is maintained at 5℃ for heating. The soil source heat pump unit 3 is stopped from operation. The third valve V3, the fourth valve V4, the first hot water circulation pump 9, and the fourteenth valve V14 on the air conditioning water supply pipe LHG of the soil source heat pump unit 3 are closed. The second hot water circulation pump 12, the first valve V1, and the second valve V2 are opened to supply heat to the air conditioning terminals in the building 6 from the phase change hot water storage tank 4.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A control method of a multi-source composite cross-seasonal high-efficiency heat storage heat pump system, characterized in that, The multi-source composite cross-season efficient heat storage heat pump system comprises a heat supplement tower system (1), an underground composite heat storage system (2), a soil source heat pump unit (3), a phase change heat storage water tank (4), an air-water heat exchanger (5) and a PVT photovoltaic and photo-thermal integrated system (7), the PVT curtain wall of the PVT photovoltaic and photo-thermal integrated system (7) is arranged on the outer wall of a building body (6), a cavity is formed between the PVT curtain wall and the wall, and the cavity is in bidirectional communication with the air side (502) of the air-water heat exchanger (5); A fifth valve (V5) and a supply air fan (8) are connected to the supply air duct (13) between the exhaust air outlet of the cavity and the hot air inlet (L1) of the air side of the air-water heat exchanger (5), and the cold air outlet (L2) of the air side of the air-water heat exchanger (5) is communicated with the supply air outlet of the cavity through an exhaust air duct (14); The air conditioning return water pipe (LHH) of the soil source heat pump unit (3) is connected to the return water outlet of the building body in sequence through a first hot water circulating pump (9) and a fourth valve (V4), and the air conditioning water supply pipe (LHG) of the soil source heat pump unit (3) is connected to the water supply outlet of the building body through a third valve (V3); The first water inlet (L3) of the phase change heat storage water tank (4) is connected to the return water outlet of the building body in sequence through a second hot water circulating pump (12) and a first valve (V1), and the first water outlet (L4) of the phase change heat storage water tank (4) is connected to the water supply outlet of the building body through a second valve (V2); An eighth valve (V8) is connected to the phase change heat storage water supply pipe (19) between the second water inlet (L5) of the phase change heat storage water tank (4) and the hot water outlet (L9) of the air-water heat exchanger (5), a ninth valve (V9) and a phase change cold water circulating pump (11) are connected to the phase change heat storage return water pipe (20) between the second water outlet (L6) of the phase change heat storage water tank (4) and the cold water inlet (L10) of the air-water heat exchanger (5); The ground source side water outlet (L8) of the soil source heat pump unit (3) is connected to the heat supplement water inlet (L12) of the heat supplement tower system (1) through an eleventh valve (V11), and the ground source side water inlet (L7) of the soil source heat pump unit (3) is connected to the water outlet of the underground composite heat storage system (2) in sequence through a fourteenth valve (V14), a geothermal side circulating pump (10) and a fifteenth valve (V15); The hot water outlet (L9) of the air-water heat exchanger (5) is connected to the water inlet of the underground composite heat storage system (2) through a sixth valve (V6) and the heat supplement water outlet (L11) of the heat supplement tower system (1), and the cold water inlet (L10) of the air-water heat exchanger (5) is connected to the underground composite heat storage system (2) through a seventh valve (V7), the geothermal side circulating pump (10) and the fifteenth valve (V15); The heat supplement water outlet (L11) of the heat supplement tower system (1) is connected to the water inlet of the underground composite heat storage system (2) through a tenth valve (V10) and a thirteenth valve (V13); A bypass pipe (17) between the heat supplement water outlet (L11) and the heat supplement water inlet (L12) of the heat supplement tower system (1) is provided with a twelfth valve (V12). At different time periods, the control system outputs signals to change the corresponding valve states to achieve different heat outputs, specifically: In summer, the soil source heat pump unit (3) is started, the third valve (V3) and the fourth valve (V4) are opened, and cold water is transported to the building (6) through the air conditioning water supply pipe (LHG) of the air conditioning side of the unit; after the indoor air conditioning terminal cools, the high-temperature cold water returns to the soil source heat pump unit (3) through the air conditioning return water pipe (LHH); at this time, the first valve (V1), the second valve (V2), the eighth valve (V8), the ninth valve (V9) and the twelfth valve (V12) are closed, and the remaining valves are opened; the first hot water circulating pump (9) and the geothermal side circulating pump (10) are opened, the phase change cold water circulating pump (11) and the second hot water circulating pump (12) are closed, and the air supply fan (8) is in a running state; In summer, the soil source heat pump unit (3) is started, the eleventh valve (V11) is opened, and the low-temperature hot water absorbing indoor waste heat is transported to the heat supplement tower system (1) through the first pipeline (15) of the unit ground source side; at this time, the twelfth valve (V12) on the bypass pipe (17) between the heat supplement outlet (L11) and the heat supplement inlet (L12) of the heat supplement tower system (1) is closed; after the heat supplement tower system (1) absorbs heat and warms up, the tenth valve (V10) and the thirteenth valve (V13) are opened, the high-temperature hot water is transported to the underground composite heat storage system (2) through the heat supplement water supply pipeline (18) for heat exchange, and the low-temperature cold water after heat exchange returns to the soil source heat pump unit (3) through the fifteenth valve (V15) and the geothermal side circulating pump (10) through the second pipeline (16) of the ground source side; In summer, the fifth valve (V5) and the air supply fan (8) are opened, the waste heat generated by the PVT curtain wall in the PVT photovoltaic and photothermal integrated system (7) is used as another high-temperature heat source to heat the air in the cavity, and the heated hot air is transported to the air side (502) of the air-water heat exchanger (5) through the air supply pipeline (13) by the air supply fan (8); at this time, the eighth valve (V8) and the ninth valve (V9) are in a closed state; In summer, the water side (501) of the air-water heat exchanger (5), the sixth valve (V6) is opened, after heat exchange with hot air, the high-temperature hot water is mixed with the hot water after warming up of the heat supplement tower system (1), and is collectively sent to the underground composite heat storage system (2); after heat storage in the underground composite heat storage system (2), low-temperature fluid is formed and enters the geothermal side circulating pump (10), and then part of the low-temperature fluid returns to the water side (501) of the air-water heat exchanger (5) through the cold water inlet (L10) by the seventh valve (V7), and the other part of the low-temperature fluid returns to the ground source side inlet (L7) of the soil source heat pump unit (3) through the fourteenth valve (V14); When heating in winter, the ground source side of the ground source heat pump unit (3) takes heat from the underground composite heat storage system (2): the fifteenth valve (V15), the ground heat side circulating pump (10) and the fourteenth valve (V14) are opened, the eleventh valve (V11) is closed, and the high-temperature hot water enters the ground source heat pump unit (3) from the ground source side water inlet (L7) through the ground source side second pipeline (16) for heat exchange, and the low-temperature fluid after heat exchange enters the ground source side first pipeline (15) from the ground source heat pump unit (3) ground source side water outlet (L8), and then returns to the underground composite heat storage system (2) through the bypass pipe (17) and the opened twelfth valve (V12) and thirteenth valve (V13), and the fluid does not pass through the heat supplement tower system (1); When storing heat in winter, the air-water heat exchanger (5) exchanges heat on both sides, and the high-temperature hot water on the water side (501) of the air-water heat exchanger (5) is delivered to the phase change heat storage water tank (4) through the opened eighth valve (V8) through the phase change heat storage water pipeline (19); after heat storage in the phase change heat storage water tank (4), the phase change cold water circulating pump (11) and the ninth valve (V9) are opened, and the low-temperature fluid returns to the water side (501) of the air-water heat exchanger (5) through the phase change heat storage return water pipeline (20); at this time, the first valve (V1) and the second valve (V2) on the other side of the phase change heat storage water tank (4) are closed, and the sixth valve (V6), the seventh valve (V7), the tenth valve (V10) and the eleventh valve (V11) are also closed; the first hot water circulating pump (9) and the phase change cold water circulating pump (11) are opened, the second hot water circulating pump (12) is closed, and the air supply fan (8) is in a running state; In winter, the night maintains the temperature of 5℃ for heating, stops running the ground source heat pump unit (3), closes the third valve (V3), the fourth valve (V4), the first hot water circulating pump (9) and the fourteenth valve (V14) on the ground source heat pump unit (3) air conditioning water pipe (LHG), opens the second hot water circulating pump (12), the first valve (V1) and the second valve (V2), and supplies heat to the air conditioning terminal in the building body (6) from the phase change heat storage water tank (4).

2. The control method of a multi-source combined cross-seasonal high-efficiency heat storage heat pump system according to claim 1, characterized in that, The air outlet is arranged on the upper part of the cavity, the air inlet is arranged on the lower part of the cavity, the air outlet and the air inlet are diagonally arranged, and the number of the air outlets is greater than that of the air inlets.

3. The control method of a multi-source combined cross-seasonal high-efficiency heat storage heat pump system according to claim 1, characterized in that, The heat supplement tower system (1) comprises a tower body (105), a variable frequency fan (101) and a water supplement device (102), the water inlet of the water supplement device (102) is connected with a heat supplement water inlet (L12) of the heat supplement tower system (1), the variable frequency fan (101) is installed on the top of the inner side of the tower body (105), a light-transmitting structure (104) is arranged in the middle of the tower body (105), a filler (103) is arranged on the inner side of the middle of the tower body (105), the water outlet of the water supplement device (102) faces the filler (103), and a heat supplement water outlet (L11) is arranged on the bottom of the tower body (105).

4. The control method of a multi-source combined cross-seasonal high-efficiency heat storage heat pump system according to claim 3, characterized in that, The filler (103) is made of a plurality of corrugated plates.

5. The control method of a multi-source combined cross-seasonal high-efficiency heat storage heat pump system according to claim 1, characterized in that, The underground composite heat storage system (2) is coupled by a water tank heat storage system and a ground buried pipe heat storage system, the underground water tank (201) of the water tank heat storage system is arranged at the center of the underground composite heat storage system (2), and the ground buried pipe (202) of the ground buried pipe heat storage system is arranged around the underground water tank (201).

6. The control method of a multi-source combined cross-seasonal high-efficiency heat storage heat pump system according to claim 5, characterized in that, In the total volume of the underground composite heat storage system (2), the volume ratio of the underground water tank (201) and the ground buried pipe (202) is not higher than 1:2; the mass flow of the underground water tank (201) and the ground buried pipe (202) accounts for half of the total mass flow.

7. The control method of a multi-source combined cross-seasonal high-efficiency heat storage heat pump system according to claim 5, characterized in that, The underground water tank (201) is in a cylindrical shape, the ground buried pipe (202) is arranged in multiple layers in a circular shape along the circumference of the underground water tank (201), and the distance between two adjacent layers of the ground buried pipe (202) is 1.5-2 m.

8. The control method of a multi-source combined cross-seasonal high-efficiency heat storage heat pump system according to claim 7, characterized in that, The two adjacent layers of the ground buried pipe (202) are arranged in a staggered manner, the odd-numbered layers of the ground buried pipe (202) are on the same radial line, and the even-numbered layers of the ground buried pipe (202) are on the same radial line.

9. The control method of a multi-source combined cross-seasonal high-efficiency heat storage heat pump system according to claim 1, characterized in that, The phase change heat storage water tank (4) adopts a solid-liquid phase change energy storage water tank, which comprises an encapsulation container and a phase change material (21), the phase change material (21) is filled in the encapsulation container, the phase change material (21) is arranged in a plate type by being bundled and arranged in a cylindrical tube and being arranged in a parallel staggered manner, and the phase change temperature of the phase change material (21) is higher than the temperature of the air conditioning water required by the building body (6).

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