An ultra-long gravity heat pipe system

Abstract

The present invention discloses an ultra-long heat pipe body inserted into the ground and a condenser. The interior of the ultra-long heat pipe body includes an evaporation section, an adiabatic section, and a condensation section from bottom to top, and a heat transfer working medium is contained therein. The condenser is arranged at the end of the condensation section of the ultra-long heat pipe body. The shape structure of the ultra-long heat pipe body is straight, curved, or multi-branched. The ultra-long heat pipe body is inserted into the ground vertically or obliquely. A solid filler and a collar are provided inside the ultra-long heat pipe body. The ultra-long gravity heat pipe of the present invention can be up to several kilometers in length. At the same time, through the inclined, curved, or multi-branched structure of the heat pipe itself, the steam fluidity inside the pipe is improved, the steam flow resistance is reduced, the solid filler is used to reduce the working medium filling amount, which helps to increase the vapor content rate of the vapor-liquid mixture, reduce the density of the vapor-liquid mixture, so that the static pressure received by the bottom liquid is reduced, making it easier to boil and improving the evaporation heat transfer efficiency. The collar increases the contact area between the liquid heat transfer working medium inside the heat pipe and the inner wall of the heat pipe, improving the evaporation heat transfer efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of geothermal exploitation, and particularly relates to an ultra-long gravity heat pipe system. Background Art

[0002] Geothermal energy, as a renewable energy source with rich reserves, cleanliness, and stability, can be divided into hydrothermal geothermal energy and hot dry rock geothermal energy. With the country's demand for energy, the development and utilization of geothermal resources have received increasing attention. For the classification of geothermal energy, it is usually divided into hydrothermal geothermal resources represented by heating, hot springs, bathing, and greenhouse cultivation, and hot dry rock resources that directly generate electricity using geothermal resources. The traditional utilization of hot dry rock often involves establishing a field test site, drilling injection wells and production wells, forming a heat reservoir with good connectivity through hydraulic fracturing, injecting a low-temperature working fluid into the injection well, heating it in the heat reservoir, pumping it to the ground power generation system through the production well, and after cascaded utilization, re-injecting it into the injection well for recycling, so as to extract deep geothermal energy. In the concept of EGS, at least one injection well and one production well are required to achieve fluid circulation, so as to achieve the extraction and utilization of geothermal energy. However, some drawbacks of EGS have also been exposed in field tests: (1) The high drilling cost; (2) It is difficult to achieve well-to-well connectivity, with a relatively high risk; (3) When achieving fluid circulation, not only a large amount of pump work is consumed, but there is also a phenomenon of working fluid leakage; (4) During the working fluid circulation process, the working fluid is in direct contact with high-temperature rocks. Ions such as calcium ions, chloride ions, and silicic acid in the fluid working fluid will cause scaling and corrosion of the pipeline after the fluid flows into the pipeline; (5) Radioactive substances such as radon (Rn222) contained in deep groundwater will cause harm to the human body; (6) Excessive use of groundwater resources may cause dangers such as land subsidence. Therefore, it is of great significance to find a heat extraction method with low investment cost, mature technology, and low risk.

[0003] As an efficient heat transfer device, a heat pipe can transfer heat from one end to the other by using the phase change of the working fluid inside the pipe. Using heat pipe technology to exploit geothermal energy can avoid the above problems. Due to its advantages such as simple manufacturing, convenient operation, low cost, and high heat transfer efficiency, the gravity heat pipe is widely used in industrial and agricultural fields. In recent years, with the country's development and utilization of new energy, the gravity heat pipe has gradually been applied to new energy fields such as solar energy and geothermal energy.

[0004] The working principle of extracting geothermal energy using a gravity heat pipe is as follows: Working fluids such as water and liquid ammonia are added to the gravity heat pipe, and its interior is evacuated to a negative pressure state by a vacuum pump. Initially, the liquid is at the bottom of the heat pipe. After the evaporation section is heated by the high-temperature rocks or high-temperature groundwater in the deep underground to reach the evaporation temperature of the liquid, the liquid absorbs heat and vaporizes into steam. Under the pressure difference of a small pressure, the steam flows through the adiabatic section to the ground condensation section. After absorbing heat through the heat exchanger in the ground condensation section, it releases heat and condenses into a liquid. Subsequently, under the action of gravity, it flows back to the evaporation section, and this cycle repeats, extracting the heat energy of the deep underground dry hot rocks to the ground for power generation and heating. From the above extraction process, it can be seen that using a gravity heat pipe to extract geothermal energy resources does not require consuming pump work, etc., which can reduce costs. In addition, only heat is taken and no water is taken in the whole process, which can avoid problems such as ground settlement and water resource pollution, and has significant advantages.

[0005] Most of the research and application of traditional gravity heat pipes are limited to the length range of 1m to 10m. However, for the gravity heat pipes used to extract geothermal energy, the length is often several kilometers, and the length-diameter ratio is as high as several thousand or even tens of thousands. The design experience parameters of conventional short heat pipes are not applicable to ultra-long gravity heat pipes. The present invention will provide a special design to solve its technical problems. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention proposes an ultra-long gravity heat pipe system with good heat transfer performance, which can operate stably and reliably for a long time, and takes into account many factors such as efficiency, pressure resistance, cost, process, and shape.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] An ultra-long gravity heat pipe system includes an ultra-long heat pipe body inserted into the ground and a condenser. The interior of the ultra-long heat pipe body includes an evaporation section, an adiabatic section, and a condensation section from bottom to top, and is filled with a heat transfer working fluid. The condenser is arranged at the end of the condensation section of the ultra-long heat pipe body. The shape structure of the ultra-long heat pipe body is a straight tube, curved, or multi-branched. The ultra-long heat pipe body is inserted into the ground vertically or obliquely. An enhanced contact component for increasing the contact area between the liquid heat transfer working fluid and the inner wall of the ultra-long heat pipe body is provided at the evaporation section of the ultra-long heat pipe body.

[0009] Furthermore, a plurality of branch pipes are arranged at the top of the ultra-long heat pipe body, and each branch pipe is separately provided with a condenser.

[0010] Furthermore, a sleeve for sleeving on the top of the condensation section of the ultra-long heat pipe body is provided on the shell side of the condenser. The sleeve is internally connected to the ultra-long heat pipe body. The condenser is also provided with a water inlet and a water outlet communicating with the tube side of the condenser.

[0011] Further, the condenser includes a housing, and the housing includes a heat exchange working medium flow path and a cooling water flow path. The heat exchange working medium flow path includes a sleeve sleeved on the top end of the condensation section of the ultra-long heat pipe body. The sleeve communicates with the inside of the housing and the other end is closed. A plurality of branch pipes are convexly provided on the side wall of the sleeve and are arranged obliquely upward. The cooling water flow path includes a cooling water inlet and a cooling water outlet provided on the housing, and the cooling water flow path enables the cooling water to exchange heat with the sleeve.

[0012] Further, the branch pipes are arranged in multiple columns centered on the central line of the sleeve, and a baffle is provided between adjacent two columns of branch pipes. The baffle is connected to the inner wall of the housing, dividing the inside of the housing into several independent spaces. A cooling water flow port is opened in the upper part or the lower part of the baffle, and the cooling water flow ports of adjacent two baffles are not arranged at the same end.

[0013] Further, the branch pipes are of square pipe structure, and a thermoelectric generator and a cooling water flat pipe are sequentially arranged on the branch pipes.

[0014] Further, the enhancement component includes a solid filler arranged at the bottom of the evaporation section inside the ultra-long heat pipe body. The diameter of the solid filler gradually decreases from low to high, and a gap is left between the solid filler and the inner wall of the ultra-long heat pipe body.

[0015] Further, the enhancement component includes at least one collar arranged at the evaporation section of the inner wall of the ultra-long heat pipe body. The collar includes an outer ring connected to the inner wall of the ultra-long heat pipe body. The outer ring includes a fixed section and an outwardly inclined section. The fixed section is connected to the inner wall of the ultra-long heat pipe body, and the outwardly inclined section is inclined from bottom to top towards the center direction of the ultra-long heat pipe body.

[0016] Further, the collar further includes an inner ring arranged inside the outer ring and a connecting plate for connecting the outer ring and the inner ring. A gap is left between the inner ring and the outer ring. The inner ring includes a vertical section and an inwardly inclined section. The length direction of the vertical section is consistent with the length direction of the evaporation section of the inner wall of the ultra-long heat pipe body, and the inwardly inclined section is inclined from bottom to top towards the center direction of the ultra-long heat pipe body.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The length of the ultra-long gravity heat pipe of the present invention can reach several kilometers. At the same time, through the inclination, bending or multi-branch structure of the heat pipe itself, the steam fluidity inside the pipe is improved, the steam flow resistance is reduced, and the liquid working medium content per unit length is greatly reduced by using solid fillers. Under the same heat absorption amount, that is, the steam output, it can help to increase the steam content rate of the vapor-liquid mixture, reduce the density of the vapor-liquid mixture, reduce the static pressure received by the bottom liquid, make it easier to boil, and use collars to increase the contact area between the heat transfer working medium inside the heat pipe and the inner wall of the heat pipe, improve the evaporation heat transfer efficiency, reduce the amount of heat transfer working medium required inside the ultra-long gravity heat pipe, and effectively improve the heat transfer use efficiency of the ultra-long evaporation section of the ultra-long gravity heat pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the straight cylindrical structure of the ultra-long heat pipe body of the ultra-long gravity heat pipe system of the present invention;

[0020] Figure 2 It is a schematic diagram of the bent structure of the ultra-long heat pipe body of the ultra-long gravity heat pipe system of the present invention;

[0021] Figure 3 It is a schematic diagram of the multi-branch structure of the ultra-long heat pipe body of the ultra-long gravity heat pipe system of the present invention;

[0022] Figure 4 It is a schematic diagram of the condenser structure of Embodiment 1 of the present invention;

[0023] Figure 5 It is a front view of the internal structure of the condenser of Embodiment 2 of the present invention;

[0024] Figure 6 It is a top view of the internal structure of the condenser of Embodiment 2 of the present invention;

[0025] Figure 7 It is a structure diagram of the condenser of Embodiment 2 of the present invention with baffle plates added to the internal structure;

[0026] Figure 8 It is an overall structure diagram of the condenser of Embodiment 2 of the present invention;

[0027] Figure 9 It is a schematic diagram of arranging a thermoelectric power generation chip on the branch pipe of the condenser of Embodiment 2 of the present invention;

[0028] Figure 10 It is a schematic diagram of multiple condensers of the ultra-long gravity heat pipe system of the present invention used side by side;

[0029] Figure 11 It is a schematic diagram of the structure of the solid filler of the ultra-long gravity heat pipe system of the present invention;

[0030] Figure 12Schematic diagram of the collar and liquid flow of the ultra-long gravity heat pipe system of the present invention;

[0031] Figure 13 Top view structural diagram of the collar of the ultra-long gravity heat pipe system of the present invention;

[0032] Figure 14 Side view structural diagram of the collar of the ultra-long gravity heat pipe system of the present invention;

[0033] Explanation of reference numerals: 1. Ultra-long heat pipe body; 2. Condenser; 21. Shell; 22. Tube bundle; 23. Air extraction port; 24. Water inlet; 25. Water outlet; 26. Sleeve; 31. Casing; 32. Branch pipe; 33. Baffle plate; 34. Outer shell; 35. Cooling water inlet and outlet; 36. Thermoelectric generator; 37. Cooling water flat tube; 4. Solid filler; 5. Collar; 51. Outer ring; 511. Fixed section; 512. Inclined section; 52. Inner ring; 521. Inclined section; 522. Vertical section; 53. Connecting plate. Detailed implementation manners

[0034] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0035] Embodiment 1

[0036] As Figures 1-3 shown, an ultra-long gravity heat pipe system includes an ultra-long heat pipe body 1 inserted into the ground and a condenser 2. The inside of the ultra-long heat pipe body 1 includes an evaporation section, an adiabatic section and a condensation section from bottom to top, and a heat transfer working medium is filled inside. The condenser 2 is arranged at the end of the condensation section of the ultra-long heat pipe body 1. An augmentation component for increasing the contact area between the heat transfer working medium and the inner wall of the ultra-long heat pipe body 1 is arranged at the evaporation section of the ultra-long heat pipe body 1. The shape and structure of the ultra-long heat pipe body 1 can be a straight cylinder, curved or multi-branched. The angle between the ultra-long heat pipe body 1 inserted into the ground and the ground horizontal line is 15° to 90°, so that the part of the ultra-long heat pipe body 1 underground can be a straight cylinder, curved or multi-branched structure inserted vertically or obliquely into the ground, specifically as Figures 1-3 shown. The vertical straight cylinder shape is beneficial to the flow of steam in the pipe, and the steam flow resistance is the smallest; while the inclined or curved shape can reduce the static pressure of the liquid in the pipe under the same length of the heat absorption pipe body of the heat pipe, making it easier to boil; the multi-branched heat pipe body shape is convenient for expanding the heat absorption area and increasing the geothermal exploitation output. Specifically, the structure of the ultra-long heat pipe body 1 should select a reasonable shape according to the geothermal resources and application objectives.

[0037] As Figure 4As shown in the figure, the tube-side flow of the condenser 2 is cooling water. The condenser 2 is provided with a water inlet 24 and a water outlet 25 that communicate with the tube side of the condenser. The steam in the ultra-long heat pipe body 1 is introduced into the shell side of the condenser 2. The shell side of the condenser 2 is provided with a sleeve 26 for sleeving the top of the condensation section of the ultra-long heat pipe body 1, so that the steam in the ultra-long heat pipe body 1 enters the shell side of the condenser 2 and exchanges heat with the tube 22 in the condenser 2. After heat exchange, the water vapor is liquefied and flows back into the evaporation section in the ultra-long heat pipe body 1 through the sleeve 26 to evaporate again. Specifically, in this embodiment, the condenser 2 can be a vertical tube-and-shell type structure. Its water inlet 24 and water outlet 25 are both arranged in the head at the same end of the condenser 2. The fluid flows through the tube 22 to the head at the other end and then flows back to form a double-tube-side flow. The sleeve 26 penetrates the head at the other end of the condenser 2 and communicates with the shell side of the shell 21 of the condenser 2. An air extraction port 23 can also be provided on the shell side of the condenser 2, and the opening and closing of the air extraction port 23 are controlled by a valve.

[0038] As Figure 10 shown, for the case of a relatively large total heat collection power, in order to improve the condensation efficiency, the end of the condensation section of the ultra-long heat pipe body 1 can be set to a structure with several bifurcated tubes. A condenser 2 is separately provided on each bifurcated tube, which can effectively improve the condensation efficiency of the condensation section of the ultra-long heat pipe body 1. It should be noted that when setting the structure of the bifurcated tubes, the pipeline shape should be conducive to the natural rise of steam and the gravity return of liquid.

[0039] As Figure 11 shown, the enhanced contact component includes a solid filler 4 arranged at the bottom of the evaporation section inside the ultra-long heat pipe body 1. The diameter of the solid filler 4 gradually decreases from low to high, and there is a gap between the solid filler 4 and the inner wall of the ultra-long heat pipe body 1. The solid filler 4 is beneficial to filling the space of the evaporation section inside the ultra-long heat pipe body 1 and increasing the contact area between the heat transfer working medium in the evaporation section and the inner wall of the ultra-long heat pipe body 1. Since the length of the ultra-long gravity heat pipe of the present invention can be up to several kilometers, the amount of the working medium to be filled is relatively large. In this way, the amount of the heat transfer working medium required can be effectively reduced. The structure of the solid filler 4 can specifically be a stepped structure or a conical structure. With such a setting, due to the fact that the liquid heat transfer working medium in the evaporation section gradually evaporates and expands in volume, and the steam continuously rises, it is necessary to gradually reduce the diameter of the filler from low to high to leave sufficient steam flow space. On the other hand, the solid filler 4 greatly reduces the content of the liquid heat transfer working medium per unit length in the ultra-long heat pipe body 1. Under the same heat absorption amount, that is, the same steam output, it can help to increase the vapor content rate of the vapor-liquid mixture, reduce the density of the vapor-liquid mixture, so that the static pressure received by the bottom liquid is reduced, and it is easier to boil.

[0040] As Figures 12-14As shown, the wicking component may further include at least one collar 5 disposed at the evaporation section of the inner wall of the ultra-long heat pipe body 1. The collar 5 includes an outer ring 51 connected to the inner wall of the ultra-long heat pipe body 1, an inner ring 52 disposed inside the outer ring 51, and a connecting plate 53 for connecting the outer ring 51 and the inner ring 52. Specifically, the outer ring 51 includes a fixed section 511 and an inclined section 512. The fixed section 511 is used to connect to the inner wall of the ultra-long heat pipe body 1, and the inclined section 512 is inclined from bottom to top towards the center of the ultra-long heat pipe body 1. There is a gap between the inner ring 52 and the outer ring 51. The inner ring 52 includes a vertical section 522 and an inclined section 521. The length direction of the vertical section 522 is the same as the length direction of the evaporation section of the inner wall of the ultra-long heat pipe body 1. The inclined section 521 is inclined from bottom to top towards the center of the ultra-long heat pipe body 1 and the inner ring 52 is inclined from bottom to top towards the center of the ultra-long heat pipe body 1. The outer ring 51 and the inner ring 52 are fixed by the connecting plate 53, and four connecting plates 53 can be symmetrically arranged in the circumferential direction of the collar 5. The inclination angles of the inclined section 521 and the inclined section 512 are preferably the same, or can be different. The function of the outer ring 51 is to hold the liquid heat transfer working medium flowing along the inner wall of the ultra-long heat pipe body 1, making it contact the inner wall of the evaporation section of the ultra-long heat pipe body 1, absorb heat and vaporize. The function of the inner ring 52 is to drain the liquid heat transfer working medium overflowing from the outer ring 51 into the outer ring 51 of the collar 5 below.

[0041] Specifically, when the ultra-long gravity heat pipe system operates, the liquid heat transfer working medium inside the ultra-long heat pipe body 1 absorbs the heat of the geothermal heat and vaporizes, moves towards the condensation section, exchanges heat with the condenser 2 at the condensation section, the gaseous heat transfer working medium releases heat and liquefies, and flows down along the inner wall of the ultra-long heat pipe body 1 back to the evaporation section. When the liquid heat transfer working medium slides back to the evaporation section along the inner wall of the ultra-long heat pipe body 1, it flows through the outer ring 51 of the collar 5, and the structure of the outer ring 51 makes the liquid heat transfer working medium hang on the inner wall of the evaporation section of the ultra-long heat pipe body 1. The liquid heat transfer working medium overflowing from the outer ring 51 flows into the outer ring 51 below through the guiding action of the inner ring 52, thereby improving the heat transfer efficiency of the liquid heat transfer working medium. At the same time, due to the presence of the solid filler 4, the content of the liquid heat transfer working medium per unit length inside the ultra-long heat pipe body 1 is greatly reduced. Under the same heat absorption amount, that is, the steam output, it can help improve the steam content rate of the vapor-liquid mixture, reduce the density of the vapor-liquid mixture, reduce the static pressure received by the bottom liquid, and make it easier to boil.

[0042] Embodiment 2

[0043] As Figures 5-9As shown, the difference from Embodiment 1 is that the condenser 2 can be designed as a tree structure. The condenser 2 includes a housing 34, and within the housing 34, there are a heat transfer working fluid flow path and a cooling water flow path. The heat transfer working fluid flow path includes a sleeve 31 sleeved on the top of the condensation section of the ultra-long heat pipe body 1, and several branch pipes 32 protruding obliquely upward are provided on the side wall of the sleeve 31. The sleeve 31 communicates with the inside of the housing 34 and the other end is closed, so that the gaseous heat transfer working fluid in the ultra-long heat pipe body 1 exchanges heat with the cooling water only through the sleeve 31 and the branch pipes 32. The branch pipes 32 are arranged in multiple columns centered on the midline of the sleeve 31. In this embodiment, for the convenience of description, there are 12 columns, and the number of branch pipes 32 in each column is the same. The branch pipes 32 are specifically square pipe structures, and a thermoelectric generation chip 36 and a cooling water flat pipe 37 are sequentially arranged on the outer side surface of each branch pipe 32, so that thermoelectric generation can be realized through this structure.

[0044] A baffle 33 is provided between two adjacent columns of branch pipes 32. The baffle 33 is connected to the inner wall of the housing 34, dividing the inside of the housing 34 into 12 independent spaces. There are cooling water flow ports at the upper or lower part of the baffle 33. The cooling water flow ports of two adjacent baffles 33 are not arranged at the same end, that is, the cooling water flow ports of two adjacent baffles 33 are arranged one above the other, forming a cooling water flow path. Such a setting makes the cooling water flow through all the branch pipes 32 in this independent space during flow, improving the heat exchange efficiency.

[0045] The cooling water inlet and outlet 35 of the condenser 2 can be arranged on two adjacent independent spaces. At the same time, the baffle 33 between these two adjacent independent spaces is not provided with a cooling water flow port. Such a setting can enable the cooling water to completely flow through all the independent spaces before flowing out, ensuring the heat exchange effect of the condenser 2. In practical applications, for high-pressure working fluids, the condenser 2 can adopt the tree structure design in this embodiment, or use the structure of the condenser 2 in Embodiment 1 in combination with the structure of the condenser 2 in this embodiment, avoiding the existence of large-diameter containers and enhancing the pressure resistance.

[0046] The above embodiments are only for illustrating the technical concept and features of the present invention. The purpose is to enable those of ordinary skill in the art to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the essence of the content of the present invention should be covered within the protection scope of the present invention.

Claims

1. An ultra-long gravity heat pipe system, characterized in that: It includes an ultra-long heat pipe body (1) inserted underground and a condenser (2). The interior of the ultra-long heat pipe body (1) includes an evaporation section, an adiabatic section, and a condensation section from bottom to top, and a heat transfer working fluid is filled inside. The condenser (2) is arranged at the end of the condensation section of the ultra-long heat pipe body (1). The shape and structure of the ultra-long heat pipe body (1) are straight cylinder, bent, or multi-branched. The ultra-long heat pipe body (1) is inserted vertically or obliquely into the ground. An enhanced contact component for increasing the contact area between the liquid heat transfer working fluid and the inner wall of the ultra-long heat pipe body (1) is provided at the evaporation section of the ultra-long heat pipe body (1). A number of bifurcated pipes are provided at the top of the ultra-long heat pipe body (1), and a condenser (2) is separately provided on each bifurcated pipe. The condenser (2) includes a housing (34). Inside the housing (34), there are a heat transfer working fluid flow path and a cooling water flow path. The heat transfer working fluid flow path includes a sleeve (31) sleeved on the top of the condensation section of the ultra-long heat pipe body (1). The sleeve (31) communicates with the inside of the housing (34) and the other end is closed. A number of branch pipes (32) protruding obliquely upward are provided on the side wall of the sleeve (31). The cooling water flow path includes a cooling water inlet and a cooling water outlet provided on the housing (21). The cooling water flow path enables the cooling water to contact and exchange heat with the sleeve (31). The branch pipes (32) are arranged in multiple columns centered on the center line of the sleeve (31). A baffle (33) is provided between adjacent two columns of branch pipes (32). The baffle (33) is connected to the inner wall of the housing (34), dividing the inside of the housing (34) into several independent spaces. A cooling water circulation port is opened in the upper or lower part of the baffle (33), and the cooling water circulation ports of adjacent two baffles (33) are not arranged at the same end.

2. The ultra-long gravity heat pipe system according to claim 1, characterized in that: A sleeve (26) for sleeving on the top of the condensation section of the ultra-long heat pipe body (1) is provided on the shell side of the condenser (2). The sleeve (26) is internally connected to the ultra-long heat pipe body (1). An inlet (24) and an outlet (25) communicating with the tube side of the condenser (2) are also provided on the condenser (2).

3. The ultra-long gravity heat pipe system according to claim 1, wherein: The branch pipe (32) has a square pipe structure, and a thermoelectric generator (36) and a cooling water flat pipe (37) are sequentially arranged on the branch pipe (32).

4. The ultra-long gravity heat pipe system according to any one of claims 1-3, characterized in that: The enhanced contact component includes a solid filler (4) arranged at the bottom of the evaporation section inside the ultra-long heat pipe body (1). The diameter of the solid filler (4) gradually decreases from low to high. A gap is left between the solid filler (4) and the inner wall of the ultra-long heat pipe body (1).

5. The ultra-long gravity heat pipe system according to any one of claims 1-3, characterized in that: The enhanced contact component includes at least one collar (5) arranged at the evaporation section of the inner wall of the ultra-long heat pipe body (1). The collar (5) includes an outer ring (51) connected to the inner wall of the ultra-long heat pipe body (1). The outer ring (51) includes a fixed section (511) and an inclined section (512). The fixed section (511) is connected to the inner wall of the ultra-long heat pipe body (1), and the inclined section (512) inclines from bottom to top towards the center direction of the ultra-long heat pipe body (1).

6. The ultra-long gravity heat pipe system according to claim 5, characterized in that: The collar (5) further includes an inner ring (52) disposed inside the outer ring (51) and a connecting plate (53) for connecting the outer ring (51) and the inner ring (52). There is a gap between the inner ring (52) and the outer ring (51). The inner ring (52) includes a vertical section (522) and an inclined section (521). The length direction of the vertical section (522) is the same as the length direction of the evaporation section of the inner wall of the ultra-long heat pipe body (1). The inclined section (521) inclines towards the center of the ultra-long heat pipe body (1) from bottom to top.

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