Power generation facility suitable for energy pile heat transfer pipe and construction method

Abstract

The invention relates to a power generation facility suitable for an energy pile heat transfer pipe and a construction method, and the power generation facility suitable for the energy pile heat transfer pipe is provided with an underground power generation module and an overground power generation module. The underground power generation module is arranged between the U-shaped heat exchange pipes, the relatively stable temperature difference environment on the upper portions of the underground U-shaped heat exchange pipes can be fully utilized, the overground power generation module is arranged in a power generation box, and a cavity capable of being opened through a valve is formed in the middle of the power generation box. The temperature difference between the temperature in the cavity and the temperature between the upper reservoir and the lower reservoir is always ensured in an air convection mode, so that continuous power generation is realized. According to the thermoelectric power generation sheet structure, the directions of the cold end and the hot end do not need to be changed during alternate cooling and heating in winter and summer, and the thermoelectric power generation sheet structure can adapt to different application scenes only by changing the current direction of the ground storage battery in the process of supplying power to the thermoelectric power generation sheet according to the Peltier effect. The preparation process of each part is mature, and the preparation process is simple.

Description

Technical Field

[0001] The present invention belongs to the technical fields of civil engineering and energy, and particularly relates to a thermoelectric power generation facility using a heat transfer pipe of an energy pile and a construction method thereof. Background Art

[0002] In the process of global development, the demand for energy shows a continuous upward trend. The operation of modern society highly depends on energy, and a huge amount of energy consumption occurs every day. At the same time, the awareness of environmental protection has taken root in people's hearts, and the emphasis on renewable energy has reached an unprecedented height. Developing new, clean and efficient energy utilization methods has become a key proposition for the sustainable development of mankind. As an extremely innovative technical concept, the energy pile ingeniously integrates building foundation engineering and geothermal energy utilization. The energy pile system is usually used in combination with a ground source heat pump, and the efficiency of the heat pump is also affected by the temperature difference. The greater the temperature difference, the more energy the heat pump needs for heat exchange. An excessive temperature difference (for example, a large difference between the underground temperature and the indoor temperature of the building) may lead to an increased working load of the heat pump, thereby reducing the overall efficiency of the system. In actual situations, the underground temperature of the energy pile system usually remains between 10°C and 15°C in winter, while the indoor temperature of the building is between 20°C and 25°C, with a temperature difference of about 5°C to 15°C. In summer, the underground temperature is approximately between 18°C and 22°C, while the indoor temperature of the building is usually between 32°C and 40°C, with a temperature difference of about 10°C to 22°C. The energy pile should have shined in the field of energy recycling, being able to provide a stable support for the building and generating electric energy by means of the temperature difference between the relatively stable underground temperature environment and the surface temperature. However, in the current actual situation, there are many limitations in the thermoelectric power generation of existing energy piles, and both the efficiency and practicality urgently need to be improved.

[0003] Before the present invention, Patent Application No. 202411278644.7 greatly improved the heat utilization rate of the thermoelectric power generation chip through the setting of an aluminum alloy heat equalizing plate and aerogel, and ensured the basic requirements of external insulation based on the operation of the sintered insulating layer, enabling the aluminum alloy heat equalizing plate to be used for the production of thermoelectric power generation chips. Utility Model Patent Application No. 202220865469.1 adopts a structure in which a solar selective absorption coating is directly combined on the outer end surface of the hot end substrate facing away from the thermoelectric power generation unit as the hot end, eliminating the thermal resistance existing in the metal plate and thermal conductive silicone grease, improving the thermoelectric conversion efficiency of the solar thermoelectric power generation unit, reducing the material cost, and improving the production efficiency at the same time. Patent Application No. 202010704784.1 discloses a bridge deck deicing, energy storage and power generation device based on an energy pile and a construction method thereof. The device can not only generate electricity using solar energy, but also reasonably configure solar energy for geothermal energy storage to ensure sufficient power supply in both winter and summer and for bridge deck deicing.

[0004] The above power generation design and operation mode between the thermoelectric power generation sheet and the energy pile fail to accurately capture the subtle but crucial temperature differences between the pile body and the surrounding environment. A large amount of potential electric energy is wasted in vain, resulting in a significant amount of energy waste. Generally speaking, thermoelectric power generation has relatively high requirements for temperature differences. Usually, a temperature difference of more than dozens of degrees is required to achieve a relatively significant power generation efficiency. Although the temperature difference between energy piles is small, in the case of long-term and continuous operation, thermoelectric power generation can still provide a part of renewable electricity for buildings or equipment, especially in systems with not particularly high power demands. It can be used as an auxiliary power source in the energy pile system to meet low-power requirements, such as LED lighting, sensors, low-power control systems, etc. In intelligent buildings or green buildings, the thermoelectric power generation of energy piles can provide a part of the power for intelligent devices and environmental monitoring systems in the building, reducing the dependence on external power and enhancing the energy self-sufficiency of the building. Therefore, it is very promising to explore a strategy to optimize the thermoelectric power generation efficiency between energy piles to meet the application scenarios with long-term and low-power demands. Summary of the Invention

[0005] This application provides a thermoelectric power generation facility and construction method using the heat transfer tube of an energy pile. The proposed thermoelectric power generation sheet structure does not need to change the directions of the cold end and the hot end during the heat and cold alternation in winter and summer. According to the Peltier effect, only by changing the current direction of the ground storage battery during the power supply process to the thermoelectric power generation sheet, different application scenarios can be adapted.

[0006] The specific technical solution of the present invention is as follows: A power generation facility applicable to the heat transfer tube of an energy pile includes an underground power generation module arranged between the U-shaped heat exchange tubes inside the energy pile and an above-ground power generation module arranged in a power generation box, which are respectively connected to a storage battery on the ground through wires. The storage battery has the function of changing the output current direction; in the two power generation modules, there are thermoelectric power generation sheets connected in series through wires. The thermoelectric power generation sheet is composed of a thermoelectric element, thermal conductive silicone grease, and a vacuum chamber heat sink plate through adhesive connection; inside the vacuum chamber heat sink plate, it is formed by coating or pressing a copper mesh and a heat sink plate shell; the above-ground power generation module is connected to the power generation box through flange interfaces on both sides; the vacuum chamber heat sink plate in the underground power generation module is in contact with the underground U-shaped heat transfer tube.

[0007] The capillary structure in the vacuum chamber heat sink plate is composed of a copper mesh, which is used to promote the circulation and reflux of the liquid working medium under capillary action; the mesh number of the copper mesh is 30 - 200 meshes, the wire diameter is between 0.05 mm and 0.3 mm, the porosity is between 40% and 80%, the thickness is between 0.1 mm and 0.3 mm, and the copper mesh forms a three-dimensional network structure in the vacuum chamber.

[0008] The composition structure of the thermoelectric power generation chip is that a thermoelectric element is placed in the middle, then thermal conductive silicone grease is applied on both sides, and finally a vacuum chamber heat sink is bonded to the outside of the thermal conductive silicone grease, thus forming a thermoelectric power generation chip.

[0009] The main structure of the power generation box is made of aluminum alloy, wrapped with heat insulation materials on the outside, and divided into 4 parts inside, namely the upper water storage tank, the lower water storage tank, the cavity, and the valves on both sides of the aluminum alloy plates sealed on both sides of the cavity.

[0010] The upper water storage tank and the lower water storage tank are of the same size. The cavity is arranged between the two water storage tanks. The upper water storage tank and the lower water storage tank are connected to the ground heat transfer pipes through flange interfaces; the upper part of the cavity is the bottom of the upper water storage tank, the lower part of the cavity is the top of the lower water storage tank, and aluminum alloy plates are provided on both sides of the cavity by welding.

[0011] A plurality of thermoelectric power generation chips are arranged on the upper and lower walls of the cavity. The thermoelectric power generation chips on the upper wall are connected in series through wires, and the thermoelectric power generation chips on the lower wall are also connected in series through wires, and the two do not interfere with each other.

[0012] Holes for the wires to enter and exit are provided at the top and bottom of the cavity for the installation and debugging of the thermoelectric power generation chips.

[0013] The wires between the thermoelectric power generation chips refer to the wires that the thermoelectric elements themselves have at the top.

[0014] The diameter of the flange interface should be the same as the diameter of the ground heat exchange pipe.

[0015] A construction method for the power generation facility described above includes the following steps: According to the size of the U-shaped heat transfer pipes designed in the project, assemble and produce the power generation box and two types of thermoelectric power generation chips with different structures, namely the thermoelectric power generation chips with single-layer thermoelectric elements applied to the ground power generation module and the thermoelectric power generation chips with multi-layer stacked thermoelectric elements applied to the underground power generation module; Install the thermoelectric power generation chips applicable to the underground power generation module one by one in the middle of the two pipes of the U-shaped heat transfer pipe through bonding and bundling connection methods, and connect the wires of the installed thermoelectric power generation chips to the storage battery located on the ground; Conduct on-site installation of the power generation box: Connect in series the thermoelectric power generation chips with single-layer thermoelectric elements made according to the quantity requirements, and connect them to the upper and lower walls of the cavity through bonding or bundling. Sort out the wires and pass them through the holes in the aluminum alloy plates on both sides of the cavity, and connect the wires to the storage battery. Then start the electrical connection inspection to ensure the safety of the power generation facility; Finally, adjust the opening and closing of the valves on both sides of the cavity of the above-ground power generation module according to the needs of different seasons, so as to form an open or closed convective temperature field. In winter, the temperature difference between the outdoor and underground temperatures is large. Open the valves to let cold air pass through the cavity. Due to the existence of the heat pump unit, when the cold air passes through the thermoelectric generation chips beside the heat storage pool, there is a large temperature difference for power generation. The same principle applies in summer. By opening the valves and allowing air to pass through the cavity, a temperature difference is always maintained on both sides of the thermoelectric generation chips for power generation. In spring and autumn, the temperature difference between the atmospheric temperature and the underground temperature is small. If the valves are opened, the temperature difference on both sides of the generation chips will decrease, reducing the power generation efficiency. At this time, close the valves, and a closed temperature convection field will be formed inside the cavity.

[0016] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: (1) The underground power generation module operates with thermoelectric generation chips made of multiple layers of stacked thermoelectric elements. The thermoelectric generation chips are arranged between the two pipes of the U-shaped heat exchange pipe, which can make full use of the relatively stable temperature difference environment above the underground U-shaped heat exchange pipe for continuous and stable power generation, and serve as an auxiliary power source in the energy pile system to meet low-power requirements, reduce the dependence on external power, and improve the energy self-sufficiency ability of buildings.

[0017] (2) The above-ground power generation module is arranged in a power generation box. The middle part of the power generation box has a cavity that can be opened by valves. By using the air convection method, the temperature in the cavity is always maintained with a temperature difference from the upper and lower storage pools, thus realizing continuous power generation. The addition of these two modules significantly improves the thermoelectric generation efficiency. In addition, the dual modules have higher power supply safety guarantees.

[0018] (3) For the proposed thermoelectric generation chip structure, there is no need to change the directions of the cold end and the hot end during the cold and heat alternation in winter and summer. According to the Peltier effect, only by changing the current direction of the ground storage battery during the power supply process to the thermoelectric generation chips can different application scenarios be adapted.

[0019] (4) The novel thermoelectric generation structure has a high heat conduction efficiency and can further reduce the temperature of the cold end well. In the winter scenario, the temperature difference between the underground and the indoor can reach about 10 to 25 °C, and in the summer scenario, the temperature difference between the underground and the indoor can reach about 15 to 32 °C, thus improving the power generation efficiency. The manufacturing process of each part is mature, the preparation process is simple, and the preparation of the power generation box is easy for engineers to understand and install, which can lay a solid foundation for the rapid implementation and stable operation of the entire energy pile power generation project. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a side view of the thermoelectric generation chip of the present invention; Figure 2Cross-sectional view of the thermoelectric power generation chip structure of the present invention; Figure 3 The ground power generation module and the underground power generation module of the present invention; Figure 4 The underground power generation module of the present invention; Figure 5 The structure of the stacked thermoelectric power generation chips in the underground power generation module of the present invention; Figure 6 The ground power generation module of the present invention.

[0021] In the appendix Figure 1-6 In the figure, 1 is a wire; 2 is a thermoelectric power generation chip; 3 is a thermoelectric element; 4 is thermal conductive silicone grease; 5 is a vacuum chamber heat sink; 6 is a copper mesh; 7 is a heat sink housing; 8 is a storage battery; 9 is a pile body; 10 is a U-shaped heat transfer pipe; 11 is a ground heat transfer pipe; 12 is a heat pump unit; 13 is a power generation box; 14 is a flange interface; 15 is a valve; 16 is a cavity; 17 is an upper reservoir; 18 is a lower reservoir; 19 is an aluminum alloy plate. Specific implementation method In order to have a clearer understanding of the technical features, objectives, and effects of the present invention, the specific construction method of the present invention is now described: (1) According to the engineering requirements, draw detailed design drawings of the U-shaped heat transfer pipe to clarify the size and shape of the heat transfer pipe. The drawings shall include the specific installation positions of the thermoelectric elements and the vacuum chamber heat sink, and the components are connected by bonding. Special attention shall be paid to the consideration of the coefficient of thermal expansion, corrosion resistance, and thermal conductivity to ensure that the design meets the environmental usage conditions.

[0023] (2) Arrange technical personnel to conduct technical docking with the manufacturers of thermoelectric elements, vacuum chamber heat sinks, and aluminum alloys respectively. Determine the production processes of the two types of thermoelectric power generation chips: one is a single-layer thermoelectric element structure for the ground power generation module; the other is a multi-layer stacked thermoelectric element structure for the underground power generation module. Strictly confirm the production processes and technical indicators, including dimensional accuracy, component compatibility, and environmental adaptability.

[0024] (3) After urging each manufacturer to complete production, conduct acceptance and quality inspection on the parts to ensure that they meet the design requirements. Transport all the components to the assembly site for pre-assembly testing to verify the matching and functionality of the components.

[0025] (4)When installing the underground module thermoelectric generator chips, it is necessary to ensure that the construction site is clean, and check the installation position of the U-shaped heat transfer pipes and the stability of their supports. Inspect the integrity of the multi-layer stacked thermoelectric generator chips, including the shell seal and the electrical wiring status. Fix the thermoelectric generator chips one by one between the two pipes of the U-shaped heat transfer pipe by means of high-strength adhesive or bundling connection. Ensure that the cold end of each chip is in good contact with the heat transfer pipe, while avoiding interference between the chips. After arranging the wires of the installed thermoelectric generator chips, connect them to the input end of the ground storage battery. Check all wire connection points to ensure good conductivity and insulation performance meeting the requirements. Under the closed state of the underground module, conduct a preliminary function test on the installed system to confirm that the thermoelectric generator chips can generate electricity normally.

[0026] (5)When installing the above-ground module thermoelectric generator chips, check the status of the single-layer thermoelectric element thermoelectric generator chips, including surface cleanliness, structural integrity and function detection. Confirm that all parts of the power generation box are ready, including aluminum alloy plates, wires and fasteners. According to the design requirements, fix the single-layer thermoelectric element thermoelectric generator chips on the upper and lower walls of the inner cavity of the power generation box by means of bonding or bundling connection. According to the quantity requirements of the chips, connect them in series to form a power generation group to ensure that the output voltage meets the design requirements. Arrange the wires of the chips so that they pass through the holes reserved in the aluminum alloy plates on both sides of the cavity. Ensure that the wires are arranged neatly, firmly connected, and docked with the storage battery. Conduct a comprehensive electrical inspection on the power generation box, including line continuity test, insulation performance detection and grounding inspection. Ensure that the power generation facilities are safe and stable and meet the operation standards.

[0027] (6)During actual seasonal adjustment and operation and maintenance, for winter and summer operations, open the valves on both sides of the cavity of the above-ground power generation module to promote air convection. Relying on the temperature difference between the atmosphere and the ground, ensure that there is always a large temperature difference on both sides of the thermoelectric generator chips to maintain high power generation efficiency. In spring and autumn, close the valves of the above-ground power generation module to make the cavity form a closed convection field. With the operation of the heat pump unit, one side of the water storage tank continuously releases heat, and the other side continuously absorbs heat, increasing the temperature difference on both sides of the chips and improving the power generation efficiency.

[0028] (7)Finally, regularly check the operating status of the U-shaped heat transfer pipes, chips and storage batteries. Reinforce the components connected by adhesive or bundling to prevent loosening caused by long-term operation. According to the actual on-site operation data, adjust the series or parallel configuration of the chips. Under the condition of large ambient temperature changes, dynamically optimize the opening and closing strategy of the cavity valves to ensure the maximization of the system operation efficiency. The present invention relates to a power generation facility and construction method applicable to heat transfer tubes of energy piles, including a wire 1, a thermoelectric generator 2, a thermoelectric element 3, thermal conductive grease 4, a vacuum chamber heat sink 5, a copper mesh 6, a heat sink housing 7, a storage battery 8, a pile body 9, a U-shaped heat transfer tube 10, an above-ground heat transfer tube 11, a heat pump unit 12, a power generation box 13, a flange interface 14, a valve 15, a cavity 16, an upper water storage tank 17, a lower water storage tank 18, and an aluminum alloy plate 19. A power generation facility applicable to heat transfer tubes of energy piles proposed by the present invention is provided with an underground power generation module and an above-ground power generation module. The underground power generation module is arranged between the U-shaped heat exchange tubes, and can make full use of the relatively stable temperature difference environment above the underground U-shaped heat exchange tubes. The above-ground power generation module is arranged in the power generation box, and the middle part of the power generation box has a cavity that can be opened through a valve. By using the air convection method, the temperature in the cavity is always kept different from the temperature difference between the upper and lower water storage tanks, so as to achieve continuous power generation. The addition of these two modules significantly improves the thermoelectric generation efficiency, and the dual modules have higher power supply safety guarantee. The proposed thermoelectric generator structure does not need to change the cold and hot ends during the cold and hot alternation in winter and summer. According to the Peltier effect, only by changing the current direction of the ground storage battery during the power supply process to the thermoelectric generator, different application scenarios can be adapted. The new thermoelectric generation structure has high thermal conductivity efficiency, the manufacturing process of each part is mature, the preparation process is simple, and the preparation of the power generation box is easy for engineers to understand and install, which can lay a solid foundation for the rapid implementation and stable operation of the entire energy pile power generation project.

[0029] The underground power generation module and the above-ground power generation module are respectively connected to the storage battery 7 located on the ground through the wire 1. Each thermoelectric generator 2 in the power generation module is connected in series through the wire 1. The number of thermoelectric generators 2 and the length of the wire 1 used in the power generation module can be increased or decreased according to the engineering requirements.

[0030] The wire between the thermoelectric generators 2 refers to the wire 1 that the top of the thermoelectric element 3 itself has. If it is necessary to increase the length of the wire 1, it can be bundled and connected with insulating tape before construction.

[0031] The thermoelectric generator 2 is composed of a thermoelectric element 3, thermal conductive grease 4, and a vacuum chamber heat sink 5 through adhesive connection. Its composition structure is that the thermoelectric element 3 is placed in the middle, then the thermal conductive grease 4 is applied on both sides, and finally the vacuum chamber heat sink 5 is adhesively attached to the outside of the thermal conductive grease 4, thus forming a thermoelectric generator.

[0032] The interior of the vacuum chamber heat pipe 5 is formed by coating or pressing a copper mesh 6 and a heat pipe outer shell 7. The copper mesh 6 in the vacuum chamber heat pipe 5 is part of its capillary structure, mainly used to promote the circulation and reflux of the liquid working medium under capillary action. The diameter of a single copper wire is about 20 - 50 microns, and the specific value depends on the heat flux density requirements of the heat pipe and the characteristics of the working medium. The mesh size is set at 100 - 200 microns, and the design of the mesh size balances the liquid flow resistance and the capillary pumping ability.

[0033] The capillary structure in the vacuum chamber heat pipe is composed of a copper mesh, which is used to promote the circulation and reflux of the liquid working medium under capillary action. Copper materials are commonly used for the capillary structure in the vacuum chamber mainly because copper has good thermal conductivity and strong corrosion resistance, which can improve the thermal management performance of the system. Usually, a copper mesh or copper wire mesh is embedded in the inner wall of the vacuum chamber to form a dense and effective capillary structure network. Specifically, the capillary structure formed by the copper mesh can provide an effective liquid transmission channel during the evaporation and condensation processes of the working liquid. They form a capillary system through small pores or channels. In this way, after the liquid evaporates into vapor during heating, the vapor moves along the capillary structure towards the cold area and condenses into a liquid in the cold area, and the liquid then returns to the heat source area through capillary action. This "evaporation - condensation" cycle helps to improve the heat conduction efficiency and heat uniformity. The copper mesh in the vacuum chamber heat pipe has the following parameters: The mesh size is defined by the mesh number. Generally, the mesh number ranges from 30 to 200. The larger the mesh number, the smaller the mesh size. The wire diameter of the copper mesh is usually between 0.05 mm and 0.3 mm. A thicker wire diameter may reduce the efficiency of capillary action, while a thinner wire diameter is beneficial to the rapid circulation of the liquid and the phase change process. The porosity of the copper mesh is usually between 40% and 80%. When the porosity is higher, the liquid can flow through the capillary structure more easily. The overall thickness of the copper mesh is usually between 0.1 mm and 0.3 mm. A thinner copper mesh has better flexibility and can adapt to vacuum chambers of different shapes. The arrangement of the copper mesh in the vacuum chamber is crucial for capillary action. The grid structure can be a simple two-dimensional planar structure or a three-dimensional three-dimensional mesh structure, depending on the design requirements and thermal management objectives. In the present invention, a three-dimensional three-dimensional mesh structure is adopted to enhance the heat dissipation ability.

[0034] The thermoelectric power generation device in the underground power generation module is formed by bonding multiple thermoelectric elements 3 with thermal conductive silicone grease 4, and its edge is in contact with the underground U-shaped heat transfer pipe through a vacuum chamber heat sink 5. The U-shaped heat transfer pipe and this stacked thermoelectric power generation device need to be prefabricated in the factory in advance to ensure that the U-shaped heat transfer pipe and the stacked thermoelectric power generation device can be in close contact. To achieve the stability of the heat transfer efficiency, the inner wall spacing of the two pipes of the U-shaped heat transfer pipe should not be too large, about 5 - 10 cm. The single pipe diameter of the U-shaped heat transfer pipe can be the same as the diameter of the above-ground heat transfer pipe, about 10 - 15 cm.

[0035] The above-ground power generation module is connected by the above-ground heat transfer pipe 11 and the power generation box 13 through the flange interfaces 14 on both sides. The diameter of the flange interface should be the same as the diameter of the above-ground heat exchange pipe 11, about 10 - 15 cm.

[0036] The power generation box 13 mentioned above has a main structure made of aluminum alloy and is wrapped with heat insulation materials to prevent heat loss. It is about 1 - 2 meters long, about 0.5 - 1 meter wide, and about 1 - 1.5 meters high. It is divided into 4 parts inside, namely the upper water storage tank 17, the lower water storage tank 18, the cavity 16, and the valves 15 on both sides of the aluminum alloy plates 19 sealed on both sides of the cavity. The two water storage tanks are of the same size, about 1 - 2 meters long and about 30 - 50 cm high. The cavity 16 is arranged between the two water storage tanks, and the valves 15 on both sides can be manually closed according to the change of seasons. The upper water storage tank 17 and the lower water storage tank 18 are connected to the above-ground heat transfer pipe 11 through the flange interfaces 14 to ensure that there is a continuous temperature difference in the cavity 16 between the two water storage tanks.

[0037] The cavity 16 mentioned above has a cuboid shape and is formed by aluminum alloy. The upper part of the cavity 16 is the bottom of the upper water storage tank 17, and the lower part of the cavity 16 is the top of the lower water storage tank 17. It is about 1 - 2 meters long, and about 10 - 20 cm wide and high. Aluminum alloy plates 19 are welded on both sides of the cavity 16, and there are holes for wires to enter and exit at the top and bottom, which is convenient for the installation and debugging of the thermoelectric power generation chips. A plurality of thermoelectric power generation chips 2 are arranged on the upper and lower walls of the cavity 16. The thermoelectric power generation chips 2 on the upper wall are connected in series through wires 1, and the thermoelectric power generation chips 2 on the lower wall are also connected in series through wires 1, and the two do not interfere with each other. The opening and closing of the valves 15 on both sides of the aluminum alloy plates 19 do not affect the connection of the wires of the thermoelectric power generation chips.

[0038] The storage battery 8 has the function of changing the direction of the output current. According to the Peltier effect, by changing the direction of the current, the hot and cold ends of the thermoelectric power generation chip can be interchanged. Thus, it saves the need to manually swap the hot and cold ends of the thermoelectric power generation chip due to the change of seasons.

[0039] The underground power generation module utilizes the temperature difference that always exists on both sides of the top of the U-shaped heat transfer tube throughout the year. Through the multi-layer stacked thermoelectric generators, this part of energy can be effectively utilized.

[0040] The above-ground power generation module operates by opening and closing the valves 15 on both sides of the cavity 16 according to different seasons, thereby forming an open or closed convective temperature field. Specifically, in winter, the temperature difference between the outdoor and underground is large. When the valve 15 is opened, cold air enters the cavity 16. Due to the presence of the heat pump unit 12, when the cold air passes through the thermoelectric generator 2 beside the thermal storage tank, a large temperature difference exists, enabling power generation. The same principle applies in summer. By opening the valve 15 and allowing air to pass through the cavity, a temperature difference is maintained on both sides of the thermoelectric generator for power generation. In spring and autumn, the temperature difference between the atmosphere and the underground is small. If the valve is opened, the temperature difference on both sides of the thermoelectric generator will decrease, reducing the power generation efficiency. At this time, the valve is closed, and a closed temperature convection field is formed inside the cavity. Due to the presence of the heat pump unit, one side of the storage tank always releases heat, while the other side always absorbs heat. At this time, the temperature difference on both sides of the thermoelectric generator increases, improving the power generation efficiency in spring and autumn.

[0041] An energy generation facility applicable to the heat transfer tubes of energy piles proposed by the present invention includes an underground power generation module and an above-ground power generation module. The underground power generation module is arranged between the U-shaped heat exchange tubes, making full use of the relatively stable temperature difference environment above the underground U-shaped heat exchange tubes. The above-ground power generation module is arranged in a power generation box, which has a cavity in the middle that can be opened by a valve. By using the air convection method, the temperature in the cavity is always maintained with a temperature difference from the upper and lower storage tanks, thereby achieving continuous power generation. The proposed thermoelectric generator structure does not require changing the directions of the cold and hot ends during the cold and hot alternation in winter and summer. According to the Peltier effect, only by changing the current direction during the power supply of the ground storage battery to the thermoelectric generator can different application scenarios be adapted. The novel thermoelectric power generation structure has a high thermal conductivity efficiency, with mature manufacturing processes for each part, a simple preparation process, and the preparation of the power generation box is also easy for engineers to understand and install, laying a solid foundation for the rapid implementation and stable operation of the entire energy pile power generation project.

[0042] The above embodiments are only preferred embodiments of the present invention and do not limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made according to the structure, characteristics, and principles within the scope of the present invention's patent application should be included within the scope of the present invention's application.

Claims

1. A power generation facility suitable for energy pile heat transfer tubes, characterized by: The invention comprises an underground power generation module arranged between U-shaped heat exchange tubes inside an energy pile and an above-ground power generation module arranged inside a power generation box, each of which is connected to a storage battery (8) located on the ground through a wire (1), and the storage battery (8) has the function of changing the direction of output current; the two power generation modules are provided with a thermoelectric power generation sheet (2) connected in series through the wire (1), and the thermoelectric power generation sheet (2) is composed of a thermoelectric element (3), a thermal conductive silicone grease (4) and a vacuum chamber heat exchange plate (5) connected by bonding; the inside of the vacuum chamber heat exchange plate (5) is formed by coating or pressing a copper mesh (6) and a heat exchange plate shell (7); the above-ground power generation module is connected by an above-ground heat transfer tube (11) and a power generation box (13) through flange interfaces (14) on both sides; the vacuum chamber heat exchange plate (5) in the underground power generation module is in contact with the underground U-shaped heat transfer tube (10).

2. A power generation facility suitable for energy pile heat transfer pipes according to claim 1, characterized in that: The capillary structure in the vacuum chamber heat spreader (5) is formed by a copper mesh (6) and is used to promote the circulation and reflux of the liquid working medium under the capillary action; the mesh number of the copper mesh (6) is 30 to 200 meshes, the wire diameter is between 0.05 mm and 0.3 mm, the porosity is between 40% and 80%, and the thickness is between 0.1 mm and 0.3 mm. The copper mesh forms a three-dimensional mesh structure in the vacuum chamber.

3. A power generation facility suitable for energy pile heat transfer pipes according to claim 1, characterized in that: The thermoelectric power generation sheet (2) is structured such that a thermoelectric element (3) is placed in the middle, thermal grease (4) is then applied to both sides, and finally a vacuum chamber heat spreader (5) is bonded to the outside of the thermal grease (4), thereby forming the thermoelectric power generation sheet.

4. A power generation facility suitable for energy pile heat transfer pipes according to claim 1, characterized in that: The main structure of the power generation box (13) is made of aluminum alloy, the outside is wrapped with heat insulation material, and the inside is divided into four parts, namely an upper water reservoir (17), a lower water reservoir (18), a cavity (16), and valves (15) on both sides of the aluminum alloy plate (19) sealed on both sides of the cavity.

5. A power generation facility suitable for energy pile heat transfer pipes according to claim 4, characterized in that: The upper water reservoir (17) and the lower water reservoir (18) are of the same size; the cavity (16) is arranged between the two water reservoirs; the upper water reservoir (17) and the lower water reservoir (18) are connected to the ground heat transfer pipe (11) via a flange interface (14); the upper portion of the cavity (16) is the bottom of the upper water reservoir (17), the lower portion of the cavity (16) is the top of the lower water reservoir (17), and aluminum alloy plates (19) are provided on both sides of the cavity (16) by welding.

6. A power generation facility suitable for energy pile heat transfer pipes according to claim 1, characterized in that: A plurality of temperature difference power generation sheets (2) are arranged on the upper and lower walls of the cavity (16); the temperature difference power generation sheets (2) on the upper wall are connected in series via a wire (1); and the temperature difference power generation sheets (2) on the lower wall are also connected in series via a wire (1), and the two do not interfere with each other.

7. A power generation facility suitable for energy pile heat transfer pipes according to claim 1, characterized in that: The top and bottom of the cavity (16) are provided with holes for the wires to enter and exit, and are used for the installation and debugging of the temperature difference power generation sheet.

8. The power generation facility suitable for energy pile heat transfer pipes according to claim 1, characterized in that: The conductive wires between the thermoelectric power generation sheets (2) refer to the conductive wires (1) at the top of the thermoelectric element (3).

9. The power generation facility suitable for energy pile heat transfer pipes according to claim 1, characterized in that: The diameter of the flange interface should be consistent with the diameter of the ground heat exchange pipe (11).

10. A construction method for the power generation facility according to claim 1, characterized in that: The following steps are involved: (1) According to the size of the U-shaped heat transfer tube designed in the project, assemble and produce the power generation box and two types of thermoelectric power generation sheets, namely, a thermoelectric power generation sheet with a single layer of thermoelectric elements used in the above-ground power generation module, and a thermoelectric power generation sheet with multiple layers of stacked thermoelectric elements used in the underground power generation module; (2) Install the thermoelectric power generation sheets suitable for the underground power generation module one by one between the two tubes of the U-shaped heat transfer tube by gluing or bundling, and connect the wires of the installed thermoelectric power generation sheets to the storage battery located on the ground; (3) Install the generator box on site: connect the manufactured single-layer thermoelectric elements in series according to the required quantity, and connect them to the upper and lower walls of the cavity by gluing or bundling. Arrange the wires and pass them through the holes of the aluminum alloy plates on both sides of the cavity, and connect the wires to the battery. Then start the electrical connection inspection to ensure the safety of the power generation facilities. (4) Finally, the valves on both sides of the cavity of the ground power generation module are adjusted according to the needs of different seasons to form an open or closed convection temperature field. In winter, the outdoor temperature is greatly different from the underground temperature. The valve (15) is opened to allow cold air to pass through the cavity (16). Due to the presence of the heat pump unit (12), the cold air has a large temperature difference when passing through the temperature difference power generation sheet (2) next to the hot water storage tank, thereby generating electricity. The same is true in summer. By opening the valve (15) and using air to pass through the cavity, it is ensured that there is always a temperature difference on both sides of the temperature difference power generation sheet, thereby generating electricity. In spring and autumn, the atmospheric temperature will be less different from the underground temperature. If the valve is opened, the temperature difference on both sides of the power generation sheet will be reduced, thereby reducing the power generation efficiency. At this time, the valve is closed, and a closed temperature convection field will be formed inside the cavity.

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