Floating type geothermal hot spring thermovolt power generation system based on natural circulation

Abstract

The invention provides a floating type geothermal hot spring thermal photovoltaic power generation system based on natural circulation, and relates to the technical field of thermal photovoltaic power generation, and the system comprises a cold end natural circulation module which is internally filled with a heat transfer working medium and is used for being immersed in a hot spring; the hot end natural circulation module is used for transferring heat of the thermal spring water to a heat transfer working medium; the thermoelectric module is formed by combining a cold end and a hot end and is arranged from top to bottom; wherein the cold end is in contact with the cold end natural circulation module, and the hot end is in contact with the hot end natural circulation module, so that temperature difference between river water and a heat transfer working medium is utilized for power generation; wherein the hot-end natural circulation module is provided with a buoyancy sleeve, and the buoyancy sleeve is used for supporting the hot-end natural circulation module to float in the hot spring, so that the thermoelectric module above the hot-end natural circulation module and the cold-end natural circulation module are separated from the hot spring water. Through the system provided by the invention, the problem of high energy consumption caused by the fact that an external power source is additionally arranged in an existing thermovolt power generation system to drive working medium circulation is solved.

Description

Technical Field

[0001] The present application relates to the technical field of thermovoltaic power generation, and in particular to a floating geothermal hot spring thermovoltaic power generation system based on natural circulation. Background Art

[0002] Geothermal resources are abundant and widely distributed, and are a renewable resource with high development potential. Geothermal development mainly consists of power generation and direct heat use. However, due to the relatively backward existing power generation technology, the development of geothermal power generation in my country has been slow. In recent years, the research and application of thermovoltaic power generation technology based on the Seebeck effect in the field of geothermal power generation has attracted widespread attention from scholars at home and abroad. Geothermal thermovoltaic power generation systems are usually composed of core components such as geothermal heat extraction devices, hot-end heat exchangers, thermoelectric devices and cold-end heat exchangers. Although thermovoltaic power generation technology has unique advantages, the performance of current thermoelectric materials themselves is relatively low. If the heat exchange working fluids at the hot and cold ends rely entirely on pump-driven circulation, the net power output of the thermovoltaic power generation system will be significantly reduced, thereby affecting the economic efficiency of the thermovoltaic power generation system and restricting its large-scale commercial promotion and application. Summary of the Invention

[0003] In response to the above problems, the present invention provides a floating geothermal hot spring thermovoltaic power generation system based on natural circulation to solve the problem of high energy consumption caused by adding an external power source to drive the working fluid circulation in the existing thermovoltaic power generation system.

[0004] The present invention provides a floating geothermal hot spring thermovoltaic power generation system based on natural circulation, the technical solution adopted is: A floating geothermal hot spring thermovoltaic power generation system based on natural circulation, the system comprising: A cold end natural circulation module, configured to communicate with a river to allow river water to circulate through the cold end natural circulation module; The hot end natural circulation module is filled with a heat transfer medium and is used to be immersed in the hot spring to transfer the heat of the hot spring water to the heat transfer medium; A thermoelectric module includes a cold end and a hot end arranged from top to bottom, wherein the cold end contacts the cold end natural circulation module, and the hot end contacts the hot end natural circulation module, so as to generate electricity by utilizing the temperature difference between the river water and the heat transfer medium; The hot end natural circulation module is provided with a buoyancy sleeve, which is used to support the hot end natural circulation module to float in the hot spring, so that the thermoelectric module and the cold end natural circulation module above the hot end natural circulation module are out of contact with the hot spring water.

[0005] As one of the preferred solutions, the cold end natural circulation module includes a water tank and a cold end heat exchanger that are interconnected, and the cold end heat exchanger is in contact with the cold end of the thermoelectric module; The water tank is arranged above the cold end heat exchanger, and both the water tank and the cold end heat exchanger are used to communicate with the river, so as to use gravity to drive the river water to circulate through the cold end heat exchanger and transfer the coldness of the river water to the cold end of the thermoelectric module.

[0006] As one of the preferred solutions, the hot end natural circulation module includes: The hot end heat exchanger is in contact with the hot end of the thermoelectric module, and the heat transfer medium is filled in the hot end heat exchanger; one side of the hot end heat exchanger is provided with the buoyancy sleeve, and the buoyancy sleeve is made of insulating material; wherein, The buoyancy sleeve is used to generate a temperature difference between different positions of the heat transfer medium in the hot end heat exchanger, so as to utilize the temperature difference to drive the heat transfer medium to circulate in the hot end heat exchanger and transfer the heat of the heat transfer medium to the hot end of the thermoelectric module.

[0007] As one of the preferred solutions, a partition is provided in the water tank, which divides the water tank into a first chamber and a second chamber which are connected at the top; the water tank is connected with a water inlet pipe, a sewage pipe, an overflow pipe and a water outlet pipe; Wherein, the first chamber is connected to the river through the water inlet pipe and is connected to the outside world through the sewage pipe; The second chamber is connected to the cold end heat exchanger through the water outlet pipe, and is connected to the river through the overflow pipe.

[0008] As one of the preferred solutions, a filter is provided on the water inlet pipe; and a three-way valve is provided on the pipeline connecting the cold end heat exchanger and the river, and the three-way valve is also used to connect with the heating terminal.

[0009] As one of the preferred solutions, the hot end heat exchanger includes a horizontal upper section, a horizontal lower section, a descending section and an ascending section, wherein the horizontal upper section, the descending section, the horizontal lower section and the ascending section are connected in sequence, and the position where two adjacent sections are connected is arc-shaped; The horizontal upper section is in contact with the hot end of the thermoelectric module, and the buoyancy sleeve is sleeved on the outer periphery of the descending section.

[0010] As one of the preferred solutions, the hot end natural circulation module further includes: A fin group includes a first fin and a second fin, wherein the first fin is arranged at an arc-shaped corner where the horizontal lower section and the ascending section are connected; A heat pipe extends horizontally from the horizontal lower section, passes through the horizontal lower section, and extends into the hot spring; the second fin is arranged on the portion of the heat pipe located in the hot spring.

[0011] As one of the preferred solutions, the inner diameter of the ascending section gradually increases in the direction approaching the horizontal upper section; and the horizontal upper section is connected with an exhaust valve and a liquid filling pipe.

[0012] As one of the preferred solutions, a thermally conductive pad is provided in the area where the cold end heat exchanger contacts the cold end of the thermoelectric module, and in the area where the hot end heat exchanger contacts the hot end of the thermoelectric module. Wherein, longitudinal ribs are respectively provided in the cold-end heat exchanger and the hot-end heat exchanger, and the longitudinal ribs extend from one side close to the thermoelectric module to the other opposite side in the corresponding heat exchanger.

[0013] As one of the preferred solutions, the system further includes a shell, which surrounds the cold-end heat exchanger and the thermoelectric module, and the shell can be opened and closed relative to the cold-end heat exchanger.

[0014] Compared with the prior art, this application has the following advantages: The present application provides a floating geothermal hot spring thermovoltaic power generation system based on natural circulation. The system includes: a cold-end natural circulation module for communicating with a river to allow river water to circulate through a cold-end natural circulation module, the interior of which is filled with a heat transfer medium; a hot-end natural circulation module for immersion in a hot spring to transfer heat from the hot spring water to the heat transfer medium; and a thermoelectric module composed of a cold end and a hot end arranged from top to bottom. The cold end contacts the cold-end natural circulation module, and the hot end contacts the hot-end natural circulation module, to generate electricity using the temperature difference between the river water and the heat transfer medium. The hot-end natural circulation module is provided with a buoyancy sleeve, which is used to support the hot-end natural circulation module floating in the hot spring, so that the thermoelectric module above the hot-end natural circulation module and the cold-end natural circulation module are separated from the hot spring water.

[0015] By adopting the technical solution of the present application, the cold-end natural circulation module is connected to the river, and the natural flow of the river water is used as a cold source to transfer cold energy to the cold end of the thermoelectric module, and the river water after transferring cold energy is discharged back into the river. The hot-end natural circulation module is immersed in the hot spring pool through a buoyancy sleeve. The operating state of the two-phase working fluid in the hot-end natural circulation module is slightly higher than the atmospheric pressure, which avoids the use of energy-consuming equipment such as vacuum pumps, realizes direct thermoelectric conversion without external power consumption, and ensures the sustainable operation of the system. In this way, both the hot and cold ends adopt a natural circulation heat exchange method, without the need for external power input. The thermoelectric module directly converts thermal energy into electrical energy through the temperature difference between the hot and cold ends. The heated river water can be used for ground source heat pumps or other thermal energy utilization. The system realizes direct thermoelectric conversion and direct thermal energy utilization without external power and rotating parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for the description of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 This is a working state diagram of a floating geothermal hot spring thermovoltaic power generation system based on natural circulation provided by one embodiment of the present application when assembled in a geothermal environment; Figure 2 is an overall cross-sectional view of a water tank provided in one embodiment of the present application; Figure 3 This is a combined structural diagram of a cold-end heat exchanger, a thermoelectric module, and a hot-end natural circulation module provided in one embodiment of the present application; Figure 4 yes Figure 3 Cross-sectional view at point A in the middle.

[0018] Description of reference numerals: 1. Filter; 2. Valve; 3. Water tank; 31. Partition; 32. First chamber; 33. Water inlet pipe; 34. Drain pipe; 35. Overflow pipe; 36. Second chamber; 37. Water outlet pipe; 4. Shell; 5. Hot-end heat exchanger; 51. Hot-end longitudinal rib; 52. Exhaust valve; 53. Filling pipe; 54. Heat pipe; 55. First fin; 56. Second fin; 6. Cold-end heat exchanger; 61. Cold-end longitudinal rib; 7. Thermoelectric module; 8. Thermal pad; 9. Buoyancy sleeve. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0020] Current thermoelectric power generation technology utilizes low-efficiency thermoelectric materials and relies heavily on pump-driven circulation, which consumes significant energy, reduces net power output, and prevents the full utilization of geothermal resources. A few low-energy geothermal thermoelectric power generation systems exist, most of which utilize heat pipe heat exchangers.

[0021] For example, a proposed thermoelectric power generation device and measurement system derives heat from a high-temperature geothermal fluid pipeline at its hot end. Two heat exchange methods are designed: one involves attaching the hot end of the thermoelectric module directly to the outer wall of the geothermal fluid pipeline, transferring heat through conduction; the other involves transferring heat through heat pipes inserted into the geothermal fluid pipeline. The cold end utilizes finned heat pipes, which dissipate heat to the environment through natural convection. A temperature difference is created between the high-temperature geothermal fluid and the ambient air across the thermoelectric module, achieving direct heat-to-electricity conversion. However, this system's heat dissipation through natural convection is ineffective, resulting in a small actual temperature difference across the thermoelectric module, which reduces the system's electrical power output. Furthermore, regardless of the heat exchange method employed, modifications to the geothermal fluid pipeline are required (for example, smoothing the outer wall of the pipeline to accommodate the thermoelectric module, or drilling holes in the pipe wall to install a heat pipe exchanger and then sealing it). Furthermore, threaded holes are required to secure the power generation device, significantly increasing the system's complexity.

[0022] Another example is a proposed hot spring geothermal perpetual thermoelectric power generation system, which consists of a hot-end heat pipe heat transfer component, a thermoelectric power generation component, and a cold-end heat pipe heat dissipation component. The evaporator section of the hot-end heat pipe is located within the hot spring geothermal well, while the condenser section contacts the hot end of the thermoelectric module, transferring the hot spring heat to the module. The evaporator section of the cold-end heat pipe contacts the cold end of the thermoelectric module, while the condenser section is located within the heat sink, dissipating heat from the module. This design allows the thermoelectric module to generate electricity by utilizing the temperature difference between its hot and cold ends. However, since the system is located above ground, the hot-end heat pipe is designed to be long and extend below the well's liquid level to extract heat. This increases the flow resistance of the working fluid within the heat pipe, significantly reducing the heat transfer efficiency of the hot end. Furthermore, the liquid sink must incorporate appropriate heat dissipation measures. Otherwise, as the water temperature in the sink increases, the heat dissipation efficiency of the system's cold end will significantly decrease, directly reducing the output power of the power generation module.

[0023] It can be seen that the development of geothermal power generation technology in my country faces obstacles. With my country's emphasis on carbon peak and carbon neutrality goals, geothermal thermovoltaic power generation technology has huge development potential in the field of renewable energy development. It is particularly suitable for areas with rich medium and low temperature geothermal resources in my country. Therefore, it is very necessary to further develop and utilize it. In view of this, in order to better utilize hydrothermal geothermal resources and solve the high energy consumption problem caused by the pump-driven working fluid circulation of the thermovoltaic power generation system, or to solve the problem of low electrical output power and complex structure of the existing temperature difference power generation system, the present invention aims to propose a floating geothermal hot spring thermovoltaic power generation system based on natural circulation. The system can make full use of the temperature difference and height difference between geothermal hot springs and natural water systems to achieve natural circulation of hot and cold end working fluids and high power output of electrical energy.

[0024] Reference Figure 1 As shown, Figure 1This is a working state diagram of the floating geothermal hot spring thermovoltaic power generation system based on natural circulation when it is installed in a geothermal environment. Figure 1 As shown, the present invention provides a floating geothermal hot spring thermovoltaic power generation system based on natural circulation, the system comprising: a cold end natural circulation module, for communicating with a river to allow river water to circulate through the cold end natural circulation module; a hot end natural circulation module, filled with a heat transfer medium, for being immersed in a hot spring to transfer the heat of the hot spring water to the heat transfer medium; a thermoelectric module 7, comprising a cold end and a hot end arranged from top to bottom, the cold end being in contact with the cold end natural circulation module, and the hot end being in contact with the hot end natural circulation module, to generate electricity by utilizing the temperature difference between the river water and the heat transfer medium; wherein the hot end natural circulation module is provided with a buoyancy sleeve 9, the buoyancy sleeve 9 being used to support the hot end natural circulation module to float in the hot spring, so that the thermoelectric module 7 above the hot end natural circulation module and the cold end natural circulation module are out of contact with the hot spring water.

[0025] Specifically, the system primarily consists of a cold-end natural circulation module, a hot-end natural circulation module, a thermoelectric module 7, and corresponding connecting piping. The cold-end natural circulation module, connected to the river, utilizes the river's natural flow as a cooling source, transferring cooling energy to the cold end of the thermoelectric module 7. The transferred river water is then returned to the river or supplied to a ground-source heat pump. This utilizes the river's natural flow, eliminating the need for an additional pump and reducing energy consumption. The continuous flow of cooling fluid maintains a low temperature at the cold end of the thermoelectric module 7.

[0026] The hot-end natural circulation module is filled with a high-efficiency heat transfer medium. After absorbing the thermal energy from the hot spring water, the heat transfer medium raises its own temperature and transfers the heat to the hot end of the thermoelectric module 7. The hot-end natural circulation module is completely immersed in the hot spring water pool. The heat transfer medium can be a phase change material. The two-phase circulation of the internal working medium absorbs the heat from the geothermal spring and improves the heat transfer efficiency of the hot-end natural circulation through the working medium phase change heat transfer.

[0027] Specifically, a gas-liquid two-phase working fluid that matches the temperature of the hot spring water can be selected, and the heat transfer efficiency of the natural circulation at the hot end can be improved through phase change heat transfer of the working fluid.

[0028] Among them, the heat transfer medium in the hot end natural circulation module is a phase change material. Therefore, there are three states in the hot end natural circulation module: gas phase, liquid phase, and gas-liquid two-phase. The three states are converted into each other in the hot end natural circulation module. That is, the heat of the hot spring water heats the phase change material and partially evaporates it, forming a gas phase and / or gas-liquid two-phase state. After flowing through the hot end, the gas phase and / or gas-liquid two-phase condenses back to the liquid phase and is heated again. The heat transfer medium in the three states has a temperature difference, which causes a density difference. The density of the gas phase is smaller than that of the liquid phase. The gas rises and the liquid falls, thus forming a circulating flow. Therefore, by filling the gas-liquid two-phase working medium, the temperature difference and density difference can be used to drive the natural circulation of the heat transfer medium. As a result, the hot end does not rely on additional pump drive, which significantly reduces energy consumption and improves the economy and sustainability of power generation.

[0029] Thermoelectric module 7 is a thermoelectric power generation module that operates based on the thermoelectric effect, generating electricity from temperature differences. Therefore, the cold end is connected to a cold-end natural circulation module to absorb cold energy, while the hot end is connected to a hot-end natural circulation module to absorb heat. By cleverly combining the natural river water of the cold-end natural circulation module with the geothermal hot springs of the hot-end natural circulation module, a large temperature difference is established between the two ends of thermoelectric module 7, achieving efficient power generation. Furthermore, the working fluid circulation at both the cold and hot ends of the system does not consume external power. Therefore, the electrical power output of thermoelectric module 7 is the net power output of the system, significantly enhancing the commercial application potential of the system.

[0030] In this embodiment, the degree of immersion of the hot end natural circulation module determines the efficiency and stability of the system's heat absorption. By adjusting the weight, shape, and structure of the buoyancy sleeve 9, the hot end natural circulation module can be fully immersed, partially immersed, or dynamically immersed in the hot spring water.

[0031] In this embodiment, the buoyancy sleeve 9 is a rectangular sleeve that runs vertically and is hollow inside. The hollow inner cavity is located around one side of the hot-end natural circulation module. Theoretical calculations show that the buoyancy generated by the underwater portion of the system is balanced with the overall gravity of the system, allowing the hot-end natural circulation module to be submerged and float in the hot spring water pool through the buoyancy sleeve 9. This ensures that the hot-end natural circulation module has maximum contact with the hot spring water, efficiently absorbing heat energy while preventing the thermoelectric module 7 above it from coming into contact with the hot spring water. Since the cold-end natural circulation module is located above the thermoelectric module 7, it is also prevented from coming into contact with the hot spring water. This protects both the cold-end natural circulation module and the thermoelectric module 7 from the effects of the hot spring water, enhancing the stability and reliability of the system.

[0032] In summary, the hot-end natural circulation module is immersed in the hot spring pool via the buoyancy sleeve 9, enhancing the natural circulation process within the pool and significantly improving the utilization efficiency of the hot spring geothermal resources. The two-phase working fluid within the hot-end natural circulation module operates at slightly above atmospheric pressure, eliminating the need for energy-consuming equipment such as vacuum pumps. This achieves direct heat-to-electricity conversion without external power consumption, ensuring sustainable system operation. Both the hot and cold ends of this system utilize a natural circulation heat exchange method, requiring no external power input. The thermoelectric module 7 directly converts thermal energy into electrical energy via the temperature difference between the hot and cold ends. The heated river water can be used for ground-source heat pumps or other thermal energy applications. This system achieves direct heat-to-electricity conversion and direct thermal energy utilization without external power or rotating components. By utilizing geothermal resources and environmental conditions in this way, the entire system combines efficient power generation with low energy consumption, economic efficiency, and environmental friendliness. This provides new insights into the sustainable development of geothermal resources and promotes breakthroughs and widespread adoption of geothermal power generation technology in my country.

[0033] In a further technical solution, the cold-end natural circulation module includes a water tank 3 and a cold-end heat exchanger 6 that are interconnected, and the cold-end heat exchanger 6 is in contact with the cold end of the thermoelectric module 7; wherein, the water tank 3 is arranged above the cold-end heat exchanger 6, and the water tank 3 and the cold-end heat exchanger 6 are both used to communicate with the river, so as to use gravity to drive the river water to circulate through the cold-end heat exchanger 6, and transfer the coldness of the river water to the cold end of the thermoelectric module 7.

[0034] In this solution, the cold-end natural circulation module is arranged on the ground. The water tank 3 is located upstream of the river, with its inlet connected to the river via an inlet pipe 33 and its outlet connected to the inlet of the cold-end heat exchanger 6. The cold-end heat exchanger 6 is located downstream of the river, with its outlet connected to the downstream of the river. The water tank 3 is located higher than the cold-end heat exchanger 6, so the cold end establishes a natural circulation of river water as the working medium through the natural height difference of the river. The upstream river water is introduced into the water tank 3, and after heat exchange in the cold-end heat exchanger 6, it is discharged back to the downstream of the river. The cold-end heat exchanger 6 is in close contact with the cold end of the thermoelectric module 7. Therefore, the cold-end heat exchanger 6 can use the river water to continuously remove heat, maintaining the low temperature of the cold end of the thermoelectric module 7 and ensuring a large temperature difference for power generation. Therefore, directly using river water as the cooling medium avoids a complex cooling water circulation system, resulting in a simple and economical design. At the same time, the natural flow of river water is driven by the height difference, significantly reducing energy consumption.

[0035] like Figure 2 The figure shows an overall cross-sectional view of the water tank 3. A partition 31 is provided inside the water tank 3, dividing it into a first chamber 32 and a second chamber 36, both connected at the top. An inlet pipe 33, a drain pipe 34, an overflow pipe 35, and an outlet pipe 37 are provided in communication with the water tank 3. The first chamber 32 is connected to the river via the inlet pipe 33 and to the outside world via the drain pipe 34. The second chamber 36 is connected to the cold-end heat exchanger 6 via the outlet pipe 37 and to the river via the overflow pipe 35.

[0036] In this embodiment, a filter 1 is installed on the water inlet pipe 33. A partition 31 is arranged within the water tank 3, forming two chambers connected at the top. The water inlet pipe 33 of the water tank 3 is connected to the upstream river and is located at the mid-height of the first chamber 32. After the river water is initially filtered by the filter 1, it enters the first chamber 32. Unfiltered solid particles and sediment settle to the bottom of the first chamber 32 by gravity. After the water level in the first chamber 32 rises above the partition 31, the secondary filtered river water flows into the second chamber 36. Because an outlet pipe 37 is provided at the bottom of the second chamber 36 and connects to the cold-end heat exchanger 6, the water then flows into the cold-end heat exchanger 6 through the outlet pipe 37 at the bottom of the water tank 3. After transferring cold energy within the cold-end heat exchanger 6, the river water is discharged to the downstream river through the outlet of the cold-end heat exchanger 6. The natural height difference of the river naturally drives the circulation of the cold-end water, completing the natural circulation of the cold-end of the system.

[0037] Therefore, the embodiments of the present application can solve the problem of unstable system power output caused by flow fluctuations in the river during the flood season and the dry season.

[0038] Specifically, an overflow pipe 35 is located at a higher point in the second chamber 36, with its outlet connected to the river. If the liquid level in the second chamber 36 rises above the overflow pipe 35, excess river water can be drained back into the river through the overflow pipe 35, thereby maintaining a relatively stable liquid level in the second chamber 36 and ensuring the stability of the flow rate and heat exchange rate at the cold end of the system. Thus, the cold end of this system uses river water as the working fluid, and a water tank 3 with an overflow structure is designed to ensure that the liquid level inside the water tank 3 remains relatively stable to cope with seasonal fluctuations in river water flow, thereby ensuring the stability of the output power of the thermovoltaic power generation system.

[0039] Specifically, a drain pipe 34 is provided at the bottom of the first chamber 32 , which can be opened periodically to clean out impurities deposited therein.

[0040] In some embodiments, the water inlet pipe 33, the sewage pipe 34, the overflow pipe 35 and the water outlet pipe 37 are arranged on different sides of the water tank 3. In some embodiments, valves 2 can be correspondingly arranged on the water inlet pipe 33, the sewage pipe 34, the overflow pipe 35 and the water outlet pipe 37.

[0041] Furthermore, a three-way valve is installed on the outlet pipe of the cold-end heat exchanger 6. After absorbing heat, the river water can be discharged back to the downstream of the river, completing the natural circulation heat exchange process at the cold end of the system. The heated river water can also be supplied to the heating terminal according to the temperature to achieve cogeneration of heat and power.

[0042] In some embodiments, the heating terminal may be a ground source heat pump, a greenhouse, a fishery, or other user terminals that directly use heat.

[0043] Preferably, a housing 4 is provided on the exterior of the cold-end heat exchanger 6. Encasing the cold-end heat exchanger 6 and thermoelectric module 7 with the housing 4 prevents the hot spring water from flushing the cold-end heat exchanger 6 and thermoelectric module 7 when the hot spring pool's liquid level fluctuates, potentially impacting system operation. The housing 4 is also retractable, its opening state adjustable according to ambient temperature. In summer, the housing 4 is closed to prevent sunlight and high ambient temperatures from causing water temperature increases, thereby preventing overheating and system performance degradation. In winter, the housing 4 is opened to take advantage of the lower ambient temperatures to further improve heat exchange efficiency.

[0044] like Figure 3 The figure shows a combined structure of a cold-end heat exchanger 6, a thermoelectric module 7, and a hot-end natural circulation module. In another embodiment, the hot-end natural circulation module includes: a hot-end heat exchanger 5 in contact with the hot end of the thermoelectric module 7, with a heat transfer medium filled therein; a buoyancy sleeve 9 is sheathed on one side of the hot-end heat exchanger 5, and the buoyancy sleeve 9 is an insulated buoyancy shell made of insulating material; the buoyancy sleeve 9 is used to generate a temperature difference between different locations of the heat transfer medium in the hot-end heat exchanger 5, thereby using the temperature difference to drive the heat transfer medium to circulate within the hot-end heat exchanger 5, transferring the heat of the heat transfer medium to the hot end of the thermoelectric module 7.

[0045] In this embodiment, a heat transfer medium is filled within the hot-end heat exchanger 5, absorbing heat from the hot spring water and transferring it to the hot end of the thermoelectric module 7. In addition to providing buoyancy, allowing the hot-end heat exchanger 5 to remain submerged and float on the water surface, the buoyancy sleeve 9 is also made of an insulating material and is mounted on one side of the hot-end heat exchanger 5. In the area covered by the buoyancy sleeve 9, due to its insulating properties, the temperature rises more slowly, and the medium remains in a high-density liquid phase, which delays the phase change process. In the exposed area not covered by the buoyancy sleeve 9, the medium rapidly absorbs the heat from the hot spring water, rapidly heating up and undergoing a phase change. Consequently, a large temperature gradient is formed between the insulating and exposed areas, amplifying the temperature difference of the heat transfer medium within the hot-end heat exchanger 5. This temperature and density difference drives the natural circulation of the hot-end medium, making the natural circulation of the medium more stable and further strengthening the driving force of the natural circulation.

[0046] Please continue reading Figure 3 As a specific description of this embodiment, the hot end heat exchanger 5 includes a horizontal upper section, a horizontal lower section, a descending section and an ascending section. The horizontal upper section, the descending section, the horizontal lower section and the ascending section are connected in sequence, and the position where two adjacent sections are connected is an arc; among them, the horizontal upper section contacts the hot end of the thermoelectric module 7, and the buoyancy sleeve 9 is arranged on the outer periphery of the descending section.

[0047] In this embodiment, the hot-end heat exchanger 5 features a four-stage design. The horizontal upper stage directly contacts the hot end of the thermoelectric module 7, transferring heat to the module and providing the heat input required for power generation. The descending stage follows the horizontal upper stage. After dissipating heat, the heat transfer medium flows downward in a liquid phase within this stage. The buoyancy sleeve 9 is positioned around the periphery of the descending stage, delaying the phase change of the liquid medium within this region and maintaining its liquid phase. The horizontal lower stage follows the descending stage and is located directly below the horizontal upper stage. The liquid medium is preheated here, rapidly increasing its temperature and causing some of the liquid phase to evaporate into a vapor phase. The partially vaporized heat transfer medium moves upward due to its reduced density, entering the ascending stage. Within this ascending stage, the heat transfer medium continues to absorb heat from the hot spring water, forming a gas-liquid two-phase state and flowing toward the horizontal upper stage. This results in a stable, continuous circulation of the heat transfer medium within the hot-end heat exchanger 5, completing the natural circulation heat exchange process for the hot-end medium.

[0048] Furthermore, the connection between two adjacent sections adopts an arc-shaped transition design to reduce the flow resistance of the working fluid during the circulation process.

[0049] Furthermore, the inner diameter of the ascending section gradually increases as it approaches the horizontal upper section. Taking into account the increase in gas-phase working medium flow rate and the resulting increase in flow resistance, the ascending section adopts a gradually expanding design. As the heat transfer medium absorbs heat in this section of the pipeline and turns into gas-liquid two-phase flow, the flow area is increased, the gas-phase working medium flow rate is reduced, and thus the flow resistance is reduced, so that the changes in flow rate and resistance remain in a relative state of balance.

[0050] In some embodiments, the top surface of the horizontal upper section is flush with the liquid level of the hot spring pool, the horizontal lower section is located directly below the horizontal upper section, the descending section connects the right sides of the horizontal upper section and the horizontal lower section, the ascending section connects the left sides of the horizontal upper section and the horizontal lower section, and the horizontal upper section, the horizontal lower section, the descending section and the ascending section are connected end to end in sequence to form a U shape.

[0051] In some embodiments, the lengths of the upper horizontal segment, the lower horizontal segment, the descending segment, and the ascending segment can be the same or different. In some embodiments, the upper horizontal segment and the lower horizontal segment can be parallel to or at an angle to each other; the descending segment and the ascending segment can be parallel to or at an angle to each other; or the upper horizontal segment can be perpendicular to or at an angle to the descending segment and / or the ascending segment; or the lower horizontal segment can be perpendicular to or at an angle to the descending segment and / or the ascending segment.

[0052] As an improvement to this embodiment, the hot end natural circulation module further includes: a fin group, including a first fin 55 and a second fin 56, the first fin 55 being arranged at the arc-shaped corner where the horizontal lower section and the ascending section are connected; a heat pipe 54, the heat pipe 54 extending horizontally from the horizontal lower section through the horizontal lower section and extending into the hot spring; the second fin 56 being arranged on the portion of the heat pipe 54 that is in the hot spring.

[0053] In this embodiment, first fins 55 are positioned at the curved corner where the lower horizontal section connects to the ascending section, further enhancing heat exchange efficiency in this area and rapidly converting the heat transfer medium into a gas-liquid two-phase system. Heat pipes 54 are also positioned within the lower horizontal section. Second fins 56 are positioned where heat pipes 54 extend into the hot spring pool. These second fins 56 transfer heat from the far end of the hot spring pool to the interior of the system, improving overall heat exchange efficiency.

[0054] There are multiple first fins 55 and multiple second fins 56. The first fins 55 and the second fins 56 can be at least one of flat fins, corrugated fins, pin fins, and wraparound fins.

[0055] In some embodiments, the plurality of first fins 55 are disposed at the arc-shaped corner where the horizontal lower section and the ascending section are connected, and are disposed on a portion of the horizontal lower section and the ascending section close to the arc-shaped corner.

[0056] like Figure 4 Shown Figure 3 Cross-sectional view at point A in the figure. As a specific explanation of this embodiment, thermally conductive gaskets 8 are provided in the area where the cold-end heat exchanger 6 contacts the cold end of the thermoelectric module 7, and in the area where the hot-end heat exchanger 5 contacts the hot end of the thermoelectric module 7. Furthermore, longitudinal ribs are provided in each of the cold-end heat exchanger 6 and the hot-end heat exchanger 5, extending from one side proximal to the thermoelectric module 7 to the opposite side within the corresponding heat exchanger.

[0057] In this embodiment, multiple thermoelectric modules 7 are arranged between the cold-end heat exchanger 6 and the hot-end heat exchanger 5. Thermally conductive silicone gaskets are placed between the ends of the thermoelectric modules 7 and the contact surfaces of the cold and hot heat exchangers to reduce contact thermal resistance. Cold-end longitudinal ribs 61 and hot-end longitudinal ribs 51 are arranged within the cold and hot-end heat exchangers, respectively. This design significantly improves the vertical temperature uniformity of the heat exchange medium. An exhaust valve 52 and a liquid filling pipe 53 are located in the upper horizontal section of the hot-end heat exchanger 5 to charge the hot-end pipeline with gas-liquid two-phase medium.

[0058] In summary, my country's geothermal resources are mainly medium- and low-temperature hydrothermal, and traditional geothermal power generation technology is difficult to promote and apply under such resource conditions. In recent years, although the research and application of thermovoltaic power generation technology based on temperature difference materials in the geothermal field have made certain progress, the heat exchange working medium circulation at the hot and cold ends of the thermovoltaic generator relies on pump drive, which consumes a high amount of electricity and reduces the net output power of the system. In order to better utilize hydrothermal geothermal resources, the present invention directly arranges the hot end heat exchange system inside the hot spring pool to collect geothermal energy, and utilizes the natural height difference of the surrounding water system to design a floating geothermal hot spring thermovoltaic power generation system based on natural circulation. The heat exchange working fluids at both the cold and hot ends of the thermovoltaic power generation system adopt natural circulation, and no external power input is required; the thermovoltaic generator is mainly arranged inside the hot spring pool, occupies a small area, has a simple design structure, and is easy to operate; the system can cope with changes in power generation caused by seasonal changes and flow fluctuations in flood and dry seasons; the system as a whole has high reliability, low maintenance requirements, can operate uninterruptedly for a long time, and stably output electrical energy and thermal energy. In this way, the present invention can provide new ideas and technical support for the large-scale development and utilization of hydrothermal geothermal resources.

[0059] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0060] It should also be noted that, in this article, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inside", "outside", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations, nor can they be understood as indicating or implying relative importance. Moreover, the term "comprises" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device that includes a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements that are inherent to such process, method, article or terminal device.

[0061] The above is a detailed introduction to the floating geothermal hot spring thermovoltaic power generation system based on natural circulation provided by this application. Specific examples are used herein to illustrate the principles and implementation methods of this application. The description of the above embodiments is intended only to facilitate understanding of this application, and the contents of this specification should not be construed as limiting this application. Furthermore, those skilled in the art will appreciate that various modifications may be made to the specific implementation methods and scope of application based on this application. It is not necessary and impossible to exhaustively enumerate all implementation methods here, and any obvious changes or modifications derived therefrom remain within the scope of protection of this application.

Claims

1. A floating geothermal hot spring thermovoltaic power generation system based on natural circulation, characterized in that: The system includes: A cold end natural circulation module, configured to communicate with a river to allow river water to circulate through the cold end natural circulation module; The hot end natural circulation module is filled with a heat transfer medium and is used to be immersed in the hot spring to transfer the heat of the hot spring water to the heat transfer medium; A thermoelectric module includes a cold end and a hot end arranged from top to bottom, wherein the cold end contacts the cold end natural circulation module, and the hot end contacts the hot end natural circulation module, so as to generate electricity by utilizing the temperature difference between the river water and the heat transfer medium; The hot end natural circulation module is provided with a buoyancy sleeve, which is used to support the hot end natural circulation module to float in the hot spring, so that the thermoelectric module and the cold end natural circulation module above the hot end natural circulation module are out of contact with the hot spring water.

2. The floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 1, characterized in that: The cold end natural circulation module includes a water tank and a cold end heat exchanger that are interconnected, and the cold end heat exchanger is in contact with the cold end of the thermoelectric module; The water tank is arranged above the cold end heat exchanger, and both the water tank and the cold end heat exchanger are used to communicate with the river, so as to use gravity to drive the river water to circulate through the cold end heat exchanger and transfer the coldness of the river water to the cold end of the thermoelectric module.

3. A floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 1 or 2, characterized in that: The hot end natural circulation module includes: The hot end heat exchanger is in contact with the hot end of the thermoelectric module, and the heat transfer medium is filled in the hot end heat exchanger; one side of the hot end heat exchanger is provided with the buoyancy sleeve, and the buoyancy sleeve is made of insulating material; wherein, The buoyancy sleeve is used to generate a temperature difference between different positions of the heat transfer medium in the hot end heat exchanger, so as to utilize the temperature difference to drive the heat transfer medium to circulate in the hot end heat exchanger and transfer the heat of the heat transfer medium to the hot end of the thermoelectric module.

4. The floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 2, characterized in that: A partition is provided in the water tank, and the partition divides the water tank into a first chamber and a second chamber which are connected at the top; the water tank is connected with a water inlet pipe, a sewage pipe, an overflow pipe and a water outlet pipe; Wherein, the first chamber is connected to the river through the water inlet pipe and is connected to the outside world through the sewage pipe; The second chamber is connected to the cold end heat exchanger through the water outlet pipe, and is connected to the river through the overflow pipe.

5. The floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 4, characterized in that: A filter is provided on the water inlet pipe; and a three-way valve is provided on the pipeline connecting the cold end heat exchanger and the river, and the three-way valve is also used to connect with the heating terminal.

6. The floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 3, characterized in that: The hot end heat exchanger includes a horizontal upper section, a horizontal lower section, a descending section and an ascending section, wherein the horizontal upper section, the descending section, the horizontal lower section and the ascending section are connected in sequence, and the position where two adjacent sections are connected is arc-shaped; The horizontal upper section is in contact with the hot end of the thermoelectric module, and the buoyancy sleeve is sleeved on the outer periphery of the descending section.

7. The floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 6, characterized in that: The hot end natural circulation module also includes: A fin group includes a first fin and a second fin, wherein the first fin is arranged at an arc-shaped corner where the horizontal lower section and the ascending section are connected; A heat pipe extends horizontally from the horizontal lower section, passes through the horizontal lower section, and extends into the hot spring; the second fin is arranged on the portion of the heat pipe located in the hot spring.

8. The floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 6, characterized in that: The inner diameter of the ascending section gradually increases in a direction approaching the horizontal upper section; the horizontal upper section is connected with an exhaust valve and a liquid filling pipe.

9. The floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 3, characterized in that: The area where the cold end heat exchanger contacts the cold end of the thermoelectric module, and the area where the hot end heat exchanger contacts the hot end of the thermoelectric module are respectively provided with thermal conductive pads; Wherein, longitudinal ribs are respectively provided in the cold-end heat exchanger and the hot-end heat exchanger, and the longitudinal ribs extend from one side close to the thermoelectric module to the other opposite side in the corresponding heat exchanger.

10. The floating geothermal hot spring thermovoltaic power generation system based on natural circulation according to claim 2, characterized in that: The system further includes a housing, which surrounds the cold-end heat exchanger and the thermoelectric module, and the housing is openable and closable relative to the cold-end heat exchanger.

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