A floating geothermal hot spring heat power generation system based on natural circulation

Abstract

The application provides a floating geothermal hot spring heat power generation system based on natural circulation, and relates to the technical field of heat power generation. The system comprises a cold end natural circulation module, a heat end natural circulation module filled with a heat transfer working medium and used for being immersed in a hot spring to transfer the heat of the hot spring water to the heat transfer working medium, and a thermoelectric module with a combined cold end and heat end arranged from top to bottom; the cold end is in contact with the cold end natural circulation module, and the heat end is in contact with the heat end natural circulation module to generate power by using the temperature difference between the river water and the heat transfer working medium; the heat end natural circulation module is provided with a buoyancy sleeve for supporting the heat end natural circulation module to float in the hot spring, so that the thermoelectric module and the cold end natural circulation module above the heat end natural circulation module are separated from the hot spring water. The system provided by the application solves the problem of high energy consumption caused by the additional external power source for driving the working medium circulation in the existing heat power generation system.

Description

TECHNICAL FIELD

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

[0002] Geothermal resources are abundant and widely distributed, and are a renewable resource with high development potential. The forms of geothermal development mainly include power generation and direct heat utilization. However, due to the relatively backward existing power generation technology, the development of geothermal power generation in China has been slow. In recent years, the thermoelectric power generation technology based on the Seebeck effect has attracted widespread attention from domestic and foreign scholars in the field of geothermal power generation. A geothermal thermoelectric power generation system usually consists of core components such as a geothermal heat extraction device, a hot end heat exchanger, a thermoelectric device and a cold end heat exchanger. Although the thermoelectric power generation technology has unique advantages, the performance of the current thermoelectric material itself is low, and if the heat and cold end heat transfer working medium completely relies on pump-driven circulation, the net power output of the thermoelectric power generation system will be significantly reduced, thereby affecting the economy of the thermoelectric power generation system and restricting its large-scale commercialization and application. SUMMARY

[0003] In view of the above problems, the present application provides a floating geothermal hot spring thermoelectric power generation system based on natural circulation to solve the problem of high energy consumption caused by the addition of an external power source to drive the working medium circulation in the existing thermoelectric power generation system.

[0004] The present application provides a floating geothermal hot spring thermoelectric power generation system based on natural circulation, which adopts the technical scheme of:

[0005] A floating geothermal hot spring thermoelectric power generation system based on natural circulation, the system comprising:

[0006] A cold end natural circulation module for communicating with a river to allow river water to circulate and flow from inside the cold end natural circulation module;

[0007] A hot end natural circulation module filled with a heat transfer working medium for immersion in a hot spring to transfer the heat of the hot spring water to the heat transfer working medium;

[0008] A thermoelectric module 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 using the temperature difference between the river water and the heat transfer working medium;

[0009] The hot end natural circulation module is provided with a buoyancy sleeve for supporting 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.

[0010] As one of the preferred solutions, the cold-end natural circulation module comprises a water tank and a cold-end heat exchanger in communication with each other, and the cold-end heat exchanger is in contact with the cold end of the thermoelectric module.

[0011] The water tank is arranged above the cold-end heat exchanger, and the water tank and the cold-end heat exchanger are both used to communicate with the river to drive the river water to circulate through the cold-end heat exchanger by gravity, and to transfer the cold energy of the river water to the cold end of the thermoelectric module.

[0012] As one of the preferred solutions, the cold-end natural circulation module comprises a water tank and a cold-end heat exchanger in communication with each other, and the cold-end heat exchanger is in contact with the cold end of the thermoelectric module.

[0013] The cold-end heat exchanger is in contact with the cold end of the thermoelectric module, and the heat transfer working medium is filled in the cold-end heat exchanger; one side of the cold-end heat exchanger is sleeved with the buoyancy sleeve, and the buoyancy sleeve is made of heat insulation material; wherein,

[0014] The buoyancy sleeve is used to generate a temperature difference of the heat transfer working medium at different positions in the cold-end heat exchanger, so as to drive the heat transfer working medium to circulate in the cold-end heat exchanger by temperature difference, and to transfer the heat of the heat transfer working medium to the cold end of the thermoelectric module.

[0015] As one of the preferred solutions, a partition is arranged in the water tank, and the partition divides the water tank into a first chamber and a second chamber in communication at the top; the water tank is provided with a water inlet pipe, a sewage pipe, an overflow pipe and a water outlet pipe in communication;

[0016] The first chamber is used to communicate with the river through the water inlet pipe, and to communicate with the outside through the sewage pipe;

[0017] The second chamber communicates with the cold-end heat exchanger through the water outlet pipe, and communicates with the river through the overflow pipe.

[0018] As one of the preferred solutions, a filter is arranged on the water inlet pipe; and a three-way valve is arranged on the pipeline for communicating the cold-end heat exchanger with the river, and the three-way valve is also used to communicate with the heat supply terminal.

[0019] As one of the preferred solutions, the cold-end heat exchanger comprises 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 sequentially communicated, and the positions where two adjacent sections are communicated are arc-shaped.

[0020] The horizontal upper section is in contact with the cold end of the thermoelectric module, and the buoyancy sleeve is sleeved on the outer periphery of the descending section.

[0021] As one of the preferred solutions, the cold-end natural circulation module further comprises:

[0022] a fin group, comprising a first fin and a second fin, the first fin being arranged at an arc-shaped corner where the horizontal lower section and the ascending section are connected;

[0023] a heat pipe, extending horizontally from the horizontal lower section through the horizontal lower section and into the hot spring, the second fin being arranged on the part of the heat pipe that is in the hot spring.

[0024] As one of the preferred solutions, the inner diameter of the ascending section gradually increases in the direction close to the horizontal upper section; the horizontal upper section is provided with an exhaust valve and a liquid filling pipe in communication.

[0025] As one of the preferred solutions, 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 a heat-conducting gasket;

[0026] The cold end heat exchanger and the hot end heat exchanger are respectively provided with longitudinal ribs, which extend from one side close to the thermoelectric module to the opposite side in the corresponding heat exchanger.

[0027] As one of the preferred solutions, the system further comprises a shell, which surrounds the cold end heat exchanger and the thermoelectric module, and the shell is openable and closable relative to the cold end heat exchanger.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The present application provides a floating geothermal hot spring heat and power generation system based on natural circulation, which comprises: a cold end natural circulation module filled with a heat transfer working medium for communicating with a river to allow river water to flow naturally in the cold end natural circulation module; a hot end natural circulation module for being immersed in a hot spring to transfer the heat of the hot spring water to the heat transfer working medium; and a thermoelectric module with 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 working medium; wherein the hot end natural circulation module is provided with a buoyancy sleeve for supporting 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.

[0030] By adopting the technical scheme of the application, the cold end natural circulation module is communicated with the river, the natural flow of the river is used as a cold source, the cold quantity is transmitted to the cold end of the thermoelectric module, and the river water after transmitting the cold quantity is discharged back to the river. The hot end natural circulation module is immersed in the hot spring pool through the buoyancy sleeve. The operating state of the two-phase working medium in the hot end natural circulation module is slightly higher than the atmospheric pressure, the use of energy-consuming devices such as vacuum pumps is avoided, direct thermoelectric conversion without external power consumption is realized, and the sustainable operation of the system is ensured. In this way, the heat exchange mode of the hot end and the cold end both adopts natural circulation, no external power input is needed, the thermoelectric module directly converts heat energy into electric energy through the temperature difference between the hot end and the cold end, and the river water after being heated can be used for ground source heat pumps or other heat utilization, and the system realizes direct thermoelectric conversion and direct heat utilization without external power and rotating parts. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical scheme of the application, the drawings needed to be used in the description of the application will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0032] Figure 1 is a working state diagram of a floating type geothermal hot spring thermoelectric power generation system based on natural circulation provided by an embodiment of the application when the system is assembled in a geothermal environment;

[0033] Figure 2 is a general sectional view of a water tank;

[0034] Figure 3 is a combined structure diagram of a cold end heat exchanger, a thermoelectric module and a hot end natural circulation module provided by an embodiment of the application;

[0035] Figure 4 is Figure 3 is a sectional view of A in FIG. 6.

[0036] BRIEF DESCRIPTION OF DRAWINGS

[0037] 1, filter; 2, valve; 3, water tank; 31, partition; 32, first chamber; 33, water inlet pipe; 34, sewage pipe; 35, overflow pipe; 36, second chamber; 37, water outlet pipe; 4, shell cover; 5, hot end heat exchanger; 51, hot end longitudinal rib; 52, exhaust valve; 53, liquid 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, heat-conducting gasket; 9, buoyancy sleeve. DETAILED DESCRIPTION

[0038] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0039] In the current geothermal power generation field, the mainstream thermoelectric material has low efficiency, mainly relies on pump-driven cycle, consumes a large amount of energy, reduces the net power output, and cannot fully utilize geothermal resources. There are some low-energy geothermal thermoelectric power generation systems today, and most of these systems use heat pipe heat exchangers.

[0040] For example, a temperature difference power generation device and a measuring system are proposed, the heat at the hot end is derived from a high-temperature geothermal fluid conveying pipeline, and two heat exchange forms are designed: one is that the hot end of the thermoelectric module is directly attached to the outer wall of the geothermal fluid pipeline, and the heat is transferred by heat conduction; the other is that the heat pipe inserted into the inside of the geothermal fluid pipeline is used for heat transfer. The cold end uses a heat pipe with fins to dissipate heat through natural air convection, and releases heat to the environment. A temperature difference is formed between the high-temperature geothermal fluid and the ambient air at the two ends of the thermoelectric module, and direct thermoelectric conversion is realized. However, the heat dissipation effect of the natural air convection is poor, which leads to a small actual temperature difference between the two ends of the thermoelectric module, thereby reducing the electric power output of the system. In addition, no matter which heat exchange mode is used, the geothermal fluid pipeline needs to be modified (for example, a smooth surface is processed on the outer wall of the pipeline to facilitate the attachment of the thermoelectric module, or a heat pipe heat exchanger is installed in the pipe wall and sealed), and a threaded hole needs to be processed to fix the power generation device, which greatly increases the complexity of the system.

[0041] For example, a hot spring geothermal sustainable temperature difference power generation system is proposed, which includes a hot end heat pipe heat transfer component, a temperature difference power generation component, and a cold end heat pipe heat dissipation component. The evaporation section of the hot end heat pipe is arranged inside the hot spring geothermal well, and the condensation section is in contact with the hot end of the thermoelectric module to transfer the hot spring heat to the thermoelectric module; the evaporation section of the cold end heat pipe of the system is in contact with the cold end of the thermoelectric module, and the condensation section is arranged inside the heat dissipation pool to dissipate heat for the thermoelectric module. Through this design, the thermoelectric module can generate electricity by utilizing the temperature difference between its cold and hot ends. However, the system is arranged on the ground, and in order to extract heat from the hot spring well, the hot end heat pipe is designed to be long and deep into the liquid surface below the hot spring well, which increases the flow resistance of the working fluid inside the heat pipe, thereby seriously affecting the heat exchange efficiency of the hot end. At the same time, the liquid pool must take certain heat dissipation measures, otherwise as the water temperature of the liquid pool rises, the heat dissipation effect of the cold end of the system will decrease significantly, thereby directly leading to the reduction of the output power of the power generation module.

[0042] It can be seen that the development of geothermal power generation technology in China is facing obstacles. With the emphasis on carbon peak and carbon neutralization in China, geothermal power generation technology has great potential for development in the field of renewable energy development, especially in areas rich in medium and low temperature geothermal resources in China, so it is necessary to further develop and utilize it. In view of this, in order to better utilize the hydrothermal geothermal resources and solve the problem of high energy consumption caused by pump-driven working fluid circulation of the heat-voltage power generation system, or solve the problem of low power output and complex structure of the existing temperature difference power generation system, the present application aims to provide a floating type geothermal hot spring heat-voltage power generation system based on natural circulation, which can make full use of the temperature difference and height difference of geothermal hot spring and natural water system, realize the natural circulation of hot and cold end working fluid and high power output of electric energy.

[0043] Referring to Figure 1 As shown in Figure 1 The working state diagram of the floating type geothermal hot spring heat-voltage power generation system based on natural circulation shown in the present application is assembled in the geothermal environment. As Figure 1 As shown in the present application, a floating type geothermal hot spring heat-voltage power generation system based on natural circulation is provided, which comprises: a cold end natural circulation module for communicating with a river to allow river water to flow in the cold end natural circulation module; a hot end natural circulation module filled with heat transfer working fluid for being immersed in a hot spring to transfer the heat of the hot spring water to the heat transfer working fluid; 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 working fluid; wherein the hot end natural circulation module is provided with a buoyancy sleeve 9 for supporting 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.

[0044] Specifically, the system mainly comprises a cold end natural circulation module, a hot end natural circulation module, a thermoelectric module 7 and corresponding connecting pipelines. The cold end natural circulation module communicates with the river to utilize the natural flow of the river water as a cold source to transfer cold to the cold end of the thermoelectric module 7, and the river water after transferring cold is discharged back to the river or supplied to a ground source heat pump. Therefore, the natural flow of the river is utilized without additional pump driving, reducing energy consumption, and the temperature of the cold end of the thermoelectric module 7 can be maintained low through the continuous flow of the cooling fluid.

[0045] The hot end natural circulation module is filled with high-efficiency heat transfer working fluid, and after the heat transfer working fluid absorbs the heat energy in the hot spring water, the temperature of the hot end natural circulation module increases, and then the temperature is transferred to the hot end of the thermoelectric module 7. The hot end natural circulation module is immersed in the hot spring pool as a whole, and the heat transfer working fluid can be selected as a phase change material, which absorbs the heat of the geothermal hot spring through the two-phase circulation of the internal working fluid, and improves the heat transfer efficiency of the hot end natural circulation through the phase change heat transfer of the working fluid.

[0046] Specifically, the gas-liquid two-phase working medium can be selected according to the temperature condition of the hot spring water, and the heat transfer efficiency of the heat source natural circulation is improved by phase change of the working medium.

[0047] The heat transfer working medium in the heat source natural circulation module is a phase change material, so there are three states of gas phase, liquid phase and gas-liquid two-phase in the heat source natural circulation module, and the three states are converted in the heat source natural circulation module, that is, the heat of the hot spring water heats the phase change material and makes it partially evaporate to form a gas phase and / or a gas-liquid two-phase state, and after flowing through the heat source, the gas phase and / or the gas-liquid two-phase condenses back to the liquid phase and is reheated. The heat transfer working medium in the three states has a temperature difference, and the temperature difference causes a density difference. The density of the gas phase is smaller than that of the liquid phase, so the gas rises and the liquid falls, thereby forming a circulating flow. Therefore, by filling the gas-liquid two-phase working medium, the natural circulation of the heat transfer working medium can be driven by using the temperature difference and the density difference, so that the heat source is not dependent on additional pump driving, which significantly reduces the energy consumption and improves the economic efficiency and sustainability of power generation.

[0048] The thermoelectric module 7 is a thermoelectric power generation module, which works on the basis of the thermoelectric effect and generates electric energy by utilizing the temperature difference. Therefore, the cold end is connected with the cold end natural circulation module to absorb cold, and the hot end is connected with the heat source natural circulation module to absorb heat, thereby establishing a large temperature difference between the two ends of the thermoelectric module 7 by skillfully combining the natural river water of the cold end natural circulation module and the geothermal hot spring of the heat source natural circulation module, so as to realize efficient power generation of the thermoelectric module 7, and the working medium circulation of the system cold and hot ends does not consume external power, so the electric power output of the thermoelectric module 7 is the net power output of the system, which significantly improves the commercial application potential of the system.

[0049] In this embodiment, the immersion degree of the heat source natural circulation module determines the efficiency and stability of the system in absorbing heat. By adjusting the weight, shape and structure of the buoyancy sleeve 9, the heat source natural circulation module can be completely immersed, partially immersed or dynamically immersed in the hot spring water.

[0050] In this embodiment, the buoyancy sleeve 9 is a rectangular sleeve that penetrates from top to bottom and is hollow inside, and the hollow inner cavity is sleeved on the outer periphery of one side of the heat source natural circulation module. The system can be balanced by theoretical calculation so that the buoyancy generated by the underwater part of the system is balanced with the overall gravity of the system, so that the heat source natural circulation module is just immersed and floats in the hot spring pool through the buoyancy sleeve 9. Therefore, the heat source natural circulation module can be maximally contacted with the hot spring water to efficiently absorb heat energy, and the thermoelectric module 7 above it will not be in contact with the hot spring water. Since the cold end natural circulation module is located above the thermoelectric module 7, the cold end natural circulation module will not be in contact with the hot spring water. Therefore, the cold end natural circulation module and the thermoelectric module 7 are protected from the influence of the hot spring water, thereby enhancing the stability and reliability of the system.

[0051] In summary, the hot-end natural circulation module, submerged in the hot spring pool via the buoyancy sleeve 9, enhances the natural circulation process within the pool, significantly improving the utilization efficiency of geothermal resources. The two-phase working fluid within the hot-end natural circulation module operates at a pressure slightly higher than atmospheric pressure, eliminating the need for energy-consuming equipment such as vacuum pumps. This achieves direct thermoelectric conversion without external power consumption, ensuring sustainable system operation. Both the hot and cold ends of this system utilize natural circulation heat exchange, requiring no external power input. The thermoelectric module 7 directly converts heat 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 heat energy utilization. The system achieves direct thermoelectric conversion and direct heat energy utilization without external power or rotating parts. By utilizing geothermal resources and environmental conditions in this way, the entire system balances high-efficiency power generation, low energy consumption, economic efficiency, and environmental friendliness, providing a new approach for the sustainable development of geothermal resources and promoting breakthroughs and widespread adoption of geothermal power generation technology in my country.

[0052] 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. The cold-end heat exchanger 6 is in contact with the cold end of the thermoelectric module 7. The water tank 3 is positioned above the cold-end heat exchanger 6, and both the water tank 3 and the cold-end heat exchanger 6 are connected to a river so that gravity drives the river water to circulate through the cold-end heat exchanger 6, transferring the coldness of the river water to the cold end of the thermoelectric module 7.

[0053] In this design, the cold-end natural circulation module is positioned on the ground. 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 section. Water tank 3 is positioned higher than the cold-end heat exchanger 6, thus establishing a natural circulation of the river water working medium at the cold end through the natural elevation difference. River water from upstream is introduced into water tank 3, undergoes heat exchange through the cold-end heat exchanger 6, and is then discharged back downstream. The cold-end heat exchanger 6 is in close contact with the cold end of the thermoelectric module 7, allowing the river water to continuously remove heat and maintain the low temperature of the cold end of the thermoelectric module 7, 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. Furthermore, the natural flow of the river water driven by the elevation difference significantly reduces energy consumption.

[0054] like Figure 2 The diagram shows a general cross-sectional view of the water tank 3. The water tank 3 is equipped with a partition 31, which divides the water tank 3 into a first chamber 32 and a second chamber 36 connected at the top. The water tank 3 is connected by an inlet pipe 33, a drain pipe 34, an overflow pipe 35, and an outlet pipe 37. The first chamber 32 is connected to a river via the inlet pipe 33 and to the outside 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.

[0055] In the embodiment, the water inlet pipe 33 is provided with the filter 1. The water tank 3 is provided with the partition plate 31 to form two upper-communicating chambers. The water inlet pipe 33 of the water tank 3 is connected to the upstream of the river and is located at the middle height position of the first chamber 32. The river water is filtered first by the filter 1 and then enters the first chamber 32. The unfiltered solid particles and sediments are settled to the bottom of the first chamber 32 by gravity. When the water level in the first chamber 32 is higher than the partition plate 31, the river water filtered secondly flows into the second chamber 36. Since the water outlet pipe 37 is arranged at the bottom of the second chamber 36 and is connected to the cold-end heat exchanger 6, the river water then flows into the cold-end heat exchanger 6 through the water outlet pipe 37 at the bottom of the water tank 3. After the cold-end heat exchanger 6 transfers cold energy, the river water is discharged from the outlet of the cold-end heat exchanger 6 to the downstream of the river. The natural difference of the river pushes the circulation of the cold-end water, and the natural circulation of the cold-end of the system is completed.

[0056] Therefore, the embodiment can solve the problem of unstable power output of the system caused by the fluctuation of the river flow in the flood season and the dry season.

[0057] Specifically, the overflow pipe 35 is arranged at the high position of the second chamber 36, and the outlet of the overflow pipe 35 is connected to the river. If the liquid level in the second chamber 36 is higher than the overflow pipe 35, the excessive river water can be discharged back to the river through the overflow pipe 35, so as to maintain the liquid level in the second chamber 36 at a relatively stable height and ensure the stability of the flow and heat exchange capacity of the cold-end of the system. In this way, the cold-end of the system uses river water as the working medium, and the water tank 3 with the overflow structure is designed to ensure that the liquid level in the water tank 3 remains relatively stable to cope with the seasonal change of the river flow, thereby ensuring the stability of the output power of the thermal power generation system.

[0058] Specifically, the blowdown pipe 34 is arranged at the bottom of the first chamber 32 and can be opened regularly to clean the impurities deposited in the first chamber 32.

[0059] In some embodiments, the water inlet pipe 33, the blowdown 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, the valves 2 can be arranged on the water inlet pipe 33, the blowdown pipe 34, the overflow pipe 35 and the water outlet pipe 37 correspondingly.

[0060] Further, the three-way valve is installed on the outlet pipeline of the cold-end heat exchanger 6. The river water can be discharged to the downstream of the river after absorbing heat to complete the natural circulation heat exchange process of the cold-end of the system, or the river water after being heated can be supplied to the heating terminal according to the temperature to realize cogeneration.

[0061] In some embodiments, the heating terminal can be a ground source heat pump, a greenhouse or a fishery and other various direct heat users.

[0062] Preferably, the cold-end heat exchanger 6 is externally designed with a casing 4. By enclosing the cold-end heat exchanger 6 and the thermoelectric module 7 with the casing 4, it is possible to prevent the hot spring water from washing over the cold-end heat exchanger 6 and the thermoelectric module 7 when the liquid level in the hot spring pool fluctuates, thus preventing any impact on the system operation. At the same time, the casing 4 is an openable and closable structure, and its opening state can be adjusted according to the ambient temperature. In summer, the casing 4 is closed to prevent the water temperature from rising due to sunlight and high ambient temperature, thereby preventing overheating and a decline in system performance; in winter, the casing 4 is opened to further improve heat exchange efficiency by utilizing the low ambient temperature.

[0063] like Figure 3 The diagram shows the combined structure of the cold-end heat exchanger 6, the thermoelectric module 7, and the hot-end natural circulation module. In another embodiment, the hot-end natural circulation module includes: a hot-end heat exchanger 5, which is in contact with the hot end of the thermoelectric module 7, and a heat transfer medium is filled inside the hot-end heat exchanger 5; a buoyancy sleeve 9 is fitted on one side of the hot-end heat exchanger 5, and the buoyancy sleeve 9 is an insulated buoyancy shell made of insulating material; wherein, the buoyancy sleeve 9 is used to generate a temperature difference in different positions of the heat transfer medium inside the hot-end heat exchanger 5, so as to use the temperature difference to drive the heat transfer medium to circulate inside the hot-end heat exchanger 5, and transfer the heat of the heat transfer medium to the hot end of the thermoelectric module 7.

[0064] In this embodiment, the heat transfer medium fills the hot-end heat exchanger 5 to absorb heat from the hot spring water and transfer it to the hot end of the thermoelectric module 7. The buoyancy sleeve 9 provides buoyancy, ensuring the hot-end heat exchanger 5 is just submerged and floats on the water surface. It is also made of insulating material and fitted onto one side of the hot-end heat exchanger 5. In the area covered by the buoyancy sleeve 9, due to its insulation, the temperature rises more slowly, and the working medium remains in a high-density liquid phase, delaying the phase change process. In the exposed area where the buoyancy sleeve 9 is not attached, the working medium can quickly absorb heat from the hot spring water, rapidly heating up and undergoing a phase change. Therefore, a large temperature gradient is formed between the insulated area and the exposed area, 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 working medium, increasing its stability and further strengthening the driving force of the natural circulation.

[0065] Please continue reading. Figure 3 As a specific illustration of this embodiment, the hot end heat exchanger 5 includes a horizontal upper section, a horizontal lower section, a descending section and a rising section. The horizontal upper section, the descending section, the horizontal lower section and the rising section are connected in sequence, and the connection position between two adjacent sections is arc-shaped. Among them, the horizontal upper section is in contact with the hot end of the thermoelectric module 7, and the buoyancy sleeve 9 is sleeved on the outer periphery of the descending section.

[0066] In the present embodiment, the four-section structure of the hot-end heat exchanger 5 is designed as follows: the horizontal upper section directly contacts the hot end of the thermoelectric module 7 to transfer heat to the thermoelectric module 7, thereby providing the required heat input for power generation. The descending section is arranged after the horizontal upper section, and the heat-absorbed heat transfer medium in liquid phase flows downward in this section. The buoyancy jacket 9 is arranged around the outer periphery of the descending section, and the phase change process of the liquid-phase heat transfer medium in this area is delayed, thereby keeping the liquid phase. The horizontal lower section is arranged after the descending section and directly below the horizontal upper section, and the liquid-phase heat transfer medium is preheated in this section, thereby rapidly increasing the temperature of the heat transfer medium and partially evaporating the liquid phase to form a gas phase. The partially gas-phase heat transfer medium moves upward due to the reduced density, enters the ascending section, and continues to absorb heat from the hot spring water in the ascending section to form a gas-liquid two-phase state and flow to the horizontal upper section. Thus, the heat transfer medium forms a stable and continuous circulating flow in the hot-end heat exchanger 5, thereby completing the natural circulation heat exchange process of the hot-end heat transfer medium.

[0067] Further, the connection between adjacent two sections is designed with an arc-shaped transition to reduce the flow resistance of the medium during circulation.

[0068] Further, the inner diameter of the ascending section gradually increases in the direction close to the horizontal upper section. Considering the increase of the gas-phase medium flow rate and the increased flow resistance caused thereby, the ascending section is designed with a gradually expanding type, thereby increasing the flow area during the heat absorption of the heat transfer medium to gas-liquid two-phase flow in this section, reducing the gas-phase medium flow rate, and thereby reducing the flow resistance, so that the changes of the flow rate and the resistance are kept in a relatively balanced state.

[0069] In some embodiments, the top surface of the horizontal upper section is flush with the liquid surface of the hot spring pool, the horizontal lower section is arranged directly below the horizontal upper section, the descending section is connected to the right side of the horizontal upper section and the horizontal lower section, and the ascending section is connected to the left side of the horizontal upper section and the horizontal lower section. The horizontal upper section, the horizontal lower section, the descending section, and the ascending section are sequentially and continuously connected to form a mouth-shaped type.

[0070] In some embodiments, the lengths of each of the horizontal upper section, the horizontal lower section, the descending section, and the ascending section can be the same or different. In some embodiments, the horizontal upper section and the horizontal lower section can be parallel to each other or at a certain angle; the descending section and the ascending section can be parallel to each other or at a certain angle; or the horizontal upper section can be perpendicular to the descending section and / or the ascending section or at a certain angle; or the horizontal lower section can be perpendicular to the descending section and / or the ascending section or at a certain angle.

[0071] As an improvement of the present embodiment, the hot-end natural circulation module further comprises: 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, penetrating through the horizontal lower section, and extending into the hot spring; and the second fin 56 being arranged on the part of the heat pipe 54 in the hot spring.

[0072] In the embodiment, the first fins 55 are arranged at the arc-shaped corner where the horizontal lower section and the rising section are communicated, which can further enhance the heat exchange efficiency of the area and make the heat transfer working medium quickly convert into gas-liquid two-phase. The heat pipes 54 are arranged in the horizontal lower section, and the part of the heat pipes 54 extending into the hot spring pool is provided with the second fins 56. The heat of the far end of the hot spring pool can be transmitted to the inside of the system through the second fins 56, and the overall heat exchange efficiency is improved.

[0073] The first fins 55 and the second fins 56 are both provided in plurality. The first fins 55 and the second fins 56 can be at least one of flat plate fins, corrugated fins, needle fins and surrounding fins.

[0074] In some embodiments, the plurality of first fins 55 are arranged at the arc-shaped corner where the horizontal lower section and the rising section are communicated, and arranged on a part of the area of the horizontal lower section and the rising section close to the arc-shaped corner.

[0075] As shown in the cross-sectional view of FIG. 6A, the cold end heat exchanger 6 and the hot end heat exchanger 5 are respectively provided with the cold end longitudinal ribs 61 and the hot end longitudinal ribs 51. Figure 4 The cold end heat exchanger 6 and the hot end heat exchanger 5 are respectively provided with the cold end longitudinal ribs 61 and the hot end longitudinal ribs 51. Figure 3 The cross-sectional view of FIG. 6A. As a specific explanation of the embodiment, the area where the cold end heat exchanger 6 contacts the cold end of the thermoelectric module 7, and the area where the hot end heat exchanger 5 contacts the hot end of the thermoelectric module 7 are respectively provided with the heat-conducting gasket 8; the cold end heat exchanger 6 and the hot end heat exchanger 5 are respectively provided with the longitudinal ribs, which extend from the side close to the thermoelectric module 7 to the opposite side in the corresponding heat exchanger.

[0076] In the embodiment, the plurality of thermoelectric modules 7 are arranged between the cold end heat exchanger 6 and the hot end heat exchanger 5, and the heat-conducting silica gel gasket is arranged between the contact surfaces of the two ends of the thermoelectric module 7 and the cold and hot heat exchangers, which is used to reduce the contact thermal resistance. The cold end longitudinal ribs 61 and the hot end longitudinal ribs 51 are respectively arranged in the cold end heat exchanger 6 and the hot end heat exchanger 5, which can greatly improve the uniformity of the temperature distribution of the heat transfer working medium in the vertical direction. The exhaust valve 52 and the liquid filling pipe 53 are respectively arranged in the horizontal upper section of the hot end heat exchanger 5, which are used to fill the gas-liquid two-phase working medium into the hot end pipeline.

[0077] In summary, China is mainly low-temperature hydrothermal geothermal resources, and the traditional geothermal power generation technology is difficult to promote and apply under such resource conditions. In recent years, although the research and application of thermoelectric power generation technology based on temperature difference materials in the field of geothermal energy has made some progress, the heat exchange working fluid circulation of the hot and cold ends of the thermoelectric generator relies on pump driving, which consumes high electric energy and reduces the net output power of the system. In order to better utilize the hydrothermal geothermal resources, the hot end heat exchange system is directly arranged in the hot spring pool to collect geothermal energy, and a floating type geothermal hot spring thermoelectric power generation system based on natural circulation is designed by using the natural elevation difference of the surrounding water system. The cold and hot end heat exchange working fluids of the thermoelectric power generation system adopt the natural circulation form, and no external power input is needed; the thermoelectric generator is mainly arranged in the hot spring pool, has small land occupation area, simple design structure and easy operation; the system can cope with the change of power generation power caused by seasonal change and flow fluctuation in wet and dry seasons; the system has high reliability as a whole, has few maintenance requirements, and can long-term uninterrupted operation and stable output of electric energy and heat energy, so that the present application can provide new ideas and technical support for the large-scale development and utilization of hydrothermal geothermal resources.

[0078] It should be noted that each embodiment in the present specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other.

[0079] It should be noted that in this paper, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application. In addition, relationship terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations, and cannot 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 the process, method, article or terminal device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or terminal device.

[0080] The above describes in detail the natural circulation based floating geothermal hot spring heat power generation system provided by the present application, and the principles and implementation manners of the present application are described by using specific examples. The above example is only used to help understand the present application, and the content of the description should not be understood as limiting the present application. Meanwhile, for those skilled in the art, according to the present application, there will be different forms of changes in the specific implementation manners and application ranges, which do not need to be enumerated here, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A floating geothermal hot spring heat power generation system based on natural circulation, characterized by, The system comprises: a cold-end natural circulation module, which is used in communication with a river to allow river water to flow in circulation within the cold-end natural circulation module; a hot-end natural circulation module, which is internally filled with a heat transfer medium, and is used to be immersed in a hot spring to transfer heat of the hot spring water to the heat transfer medium; a thermoelectric module, which comprises a cold end and a hot end arranged from top to bottom, 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 to generate electricity by using temperature difference between the river water and the heat transfer medium; wherein 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; the cold-end natural circulation module comprises a water tank and a cold-end heat exchanger in communication with each other, the cold-end heat exchanger is in contact with the cold end of the thermoelectric module; the water tank is provided with a partition plate, which divides the water tank into a first chamber and a second chamber in communication at the top; the water tank is provided with an inlet pipe, a blowdown pipe, an overflow pipe and an outlet pipe in communication; wherein the first chamber is used to communicate with the river through the inlet pipe, and is used to communicate with the outside through the blowdown pipe; wherein the second chamber is in communication with the cold-end heat exchanger through the outlet pipe, and is used to communicate with the river through the overflow pipe; the hot-end natural circulation module comprises a hot-end heat exchanger 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 sleeved with the buoyancy sleeve; the hot-end heat exchanger comprises a horizontal upper section, a horizontal lower section, a descending section and an ascending section, which are sequentially communicated, and the positions where adjacent two sections are communicated are arc-shaped; wherein 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.

2. A floating geothermal hot spring heat power generation system based on natural circulation according to claim 1, characterized in that, The water tank is arranged above the cold-end heat exchanger, and the water tank and the cold-end heat exchanger are both used to communicate with the river to drive the river water to flow through the cold-end heat exchanger by gravity, so as to transfer cold energy of the river water to the cold end of the thermoelectric module.

3. A natural circulation based floating geothermal hot spring heat power generation system according to claim 1 or 2, characterized in that, The buoyancy sleeve is made of thermal insulation material; wherein the buoyancy sleeve is used to generate temperature difference of the heat transfer medium at different positions in the hot-end heat exchanger, so as to drive the heat transfer medium to flow in circulation in the hot-end heat exchanger by using temperature difference, and transfer heat of the heat transfer medium to the hot end of the thermoelectric module.

4. A natural circulation based floating geothermal hot spring thermal power generation system according to claim 1, wherein, A filter is arranged on the inlet pipe; and a three-way valve is arranged on the pipeline in communication with the river and the cold-end heat exchanger, and the three-way valve is also used to communicate with a heat supply terminal.

5. A natural circulation based floating geothermal hot spring thermal power generation system according to claim 1, wherein, The hot-end natural circulation module further comprises: a fin group comprising a first fin and a second fin, the first fin is arranged at an arc-shaped corner where the horizontal lower section and the ascending section are communicated; A heat pipe extends horizontally from the horizontal lower section and into the hot spring; the second fins are arranged on the part of the heat pipe in the hot spring.

6. A natural circulation based floating geothermal hot spring thermal power generation system according to claim 1, wherein, The inner diameter of the ascending section gradually increases in the direction close to the horizontal upper section; the horizontal upper section is provided with an exhaust valve and a liquid filling pipe in communication.

7. A floating geothermal hot spring heat 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 a heat-conducting gasket. The cold end heat exchanger and the hot end heat exchanger are respectively provided with longitudinal ribs.

8. A floating geothermal hot spring heat power generation system based on natural circulation according to claim 2, characterized in that, The system further comprises a shell that surrounds the cold end heat exchanger and the thermoelectric module, and the shell is openable and closable relative to the cold end heat exchanger.

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