A new type of vacuum heat collecting tube
By introducing microchannel heat-absorbing cores, spiral fins, and corrugated tube structures into solar collector tubes, the problems of insufficient heat exchange area and uneven temperature are solved, achieving efficient heat transfer and stable heating.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HAINAN YUXING ENERGY TECH CO LTD
- Filing Date
- 2025-07-04
- Publication Date
- 2026-08-04
AI Technical Summary
The limited heat exchange area of existing solar collector tubes results in high contact thermal resistance and heat transfer thermal resistance between water and the absorber, as well as uneven temperature distribution, which affects the heating effect.
A microchannel heat absorption core was designed, including dense shallow channels and sparse deep channels, combined with spiral blades and corrugated tube structures to enhance heat absorption and reduce flow resistance. Heat transfer was enhanced by phase change material heat storage and porous metal foam.
It significantly improves heat transfer efficiency and response speed, reduces temperature unevenness, extends heating time, improves light utilization, and reduces pump power loss.
Smart Images
Figure CN224593469U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar collector tube technology, specifically to a novel vacuum collector tube. Background Technology
[0002] A solar collector tube consists of an inner glass tube with a solar selective absorption coating and a coaxial outer glass tube. A high vacuum is created between the inner and outer tubes. It is a device used to collect solar heat to heat the fluid medium inside the tube.
[0003] The existing heat exchange area of the collector tubes is limited, resulting in a large contact thermal resistance and heat transfer thermal resistance between the water and the absorber. This reduces the heat transfer efficiency and response speed of the water. In addition, since the collector tubes are usually placed at an angle, there are sun-facing and shaded sides when exposed to sunlight. That is, the top of the collector tube is the sun-facing side, and the bottom of the collector tube is the shaded side. The existing single-glass structure of the collector tubes can only heat the part of the water flowing inside that faces the sunlight, while the heating effect on the part of the water that faces away from the sunlight is poor. This leads to uneven temperature of the water inside the tube and affects the heating effect. Utility Model Content
[0004] In order to solve the problems existing in the prior art, the purpose of this application is to provide a new type of vacuum heat collection tube.
[0005] The novel vacuum heat collection tube described in this application includes a glass outer tube and a heat collection tube. The heat collection tube is disposed inside the glass outer tube, and a vacuum interlayer is formed between the glass outer tube and the heat collection tube. An absorption coating is provided on the outer wall of the heat collection tube, and a sealing ring is fixedly connected to the end between the glass outer tube and the heat collection tube.
[0006] The inner wall of the heat collection tube is equipped with a microchannel heat absorption core. The top of the microchannel heat absorption core is designed with dense shallow channels to enhance heat absorption, while the bottom is designed with sparse deep channels to reduce flow resistance. The outer end of the glass tube is equipped with a connecting end tube.
[0007] Furthermore, it is particularly preferred that the microchannel heat absorption core is provided with spiral blades.
[0008] In addition, it is particularly preferred that the spiral plate is a spiral metal sheet (such as copper / aluminum), which has a much higher thermal conductivity than plastic or ceramic, and can quickly transfer heat from the channel wall to the working fluid.
[0009] Furthermore, it is particularly preferred that the end of the heat collection tube near the sealing ring has a corrugated pipe.
[0010] Furthermore, it is particularly preferred that the bellows be a Kovar alloy transition ring.
[0011] Furthermore, it is particularly preferred that a gap is maintained between the corrugated tube and the inner wall of the outer glass tube.
[0012] Furthermore, it is particularly preferred that the outer wall of the heat collection tube is provided with an annular tube for storing phase change material.
[0013] In addition, it is particularly preferred that the annular tube is made of a light-transmitting material.
[0014] Furthermore, it is particularly preferred that the annular tube contains porous metal foam.
[0015] Furthermore, it is particularly preferred that the microporous structure (pore size 0.5-2 mm) of the porous metal foam can induce micro-convection after the phase change material melts, further enhancing heat transfer.
[0016] The novel vacuum heat collection tube described in this application has the following advantages:
[0017] The microchannel heat absorber core greatly increases the heat exchange area, significantly reduces the contact thermal resistance and heat transfer thermal resistance between water and the heat absorber, and improves heat transfer efficiency and response speed. At the same time, the top of the heat absorber core is designed with dense shallow channels to further enhance heat absorption, while the bottom uses sparse deep channels to reduce flow resistance. Thus, the channel design on the heat absorber core improves the utilization rate of light and reduces pump power loss.
[0018] By designing spiral blades, the water flows through the microchannel heat absorption core, disrupting the laminar boundary layer and causing turbulence. This mixes the water, preventing the existing single-glass heat collection tube structure from only heating the portion of the water facing the sun while neglecting the portion facing away from the sun. This results in uneven water temperature within the tube, affecting the heating effect.
[0019] Meanwhile, the corrugated design allows for axial expansion differences between the collector tube (directly heated) and the outer glass tube (at ambient temperature) during operation. The flexible structure of the corrugated tube prevents stress concentration at the glass-metal sealing interface from causing cracks and vacuum failure. Furthermore, the gap between the corrugated tube and the inner wall of the outer glass tube prevents minor bending or radial expansion of the glass tube at high temperatures. This gap also ensures that the corrugated tube does not contact the inner wall of the outer glass tube, preventing friction damage or stress concentration. Attached Figure Description
[0020] Figure 1 This is a three-dimensional structural schematic diagram of a novel vacuum heat collection tube described in this application;
[0021] Figure 2 This is a first partial cross-sectional view of a novel vacuum heat collection tube described in this application;
[0022] Figure 3 This is a second partial cross-sectional view of a novel vacuum heat collection tube described in this application;
[0023] Figure 4 This is an enlarged view of point A of the novel vacuum heat collection tube described in this application;
[0024] Figure 5 This is a structural diagram of the 5-microchannel heat absorption core of a novel vacuum heat collection tube as described in this application.
[0025] Explanation of reference numerals in the attached drawings: 1-glass outer tube, 11-connecting end tube, 2-collector tube, 3-absorption coating, 4-sealing ring, 5-microchannel heat absorption core, 6-spiral blade, 7-corrugated tube, 8-ring tube, 9-porous metal foam. Detailed Implementation
[0026] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0027] To simplify the disclosure of this invention, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0028] Example
[0029] A new type of vacuum heat collection tube, such as Figure 1-5As shown, it includes a glass outer tube 1 and a heat collection tube 2. The heat collection tube 2 is installed inside the glass outer tube 1. A vacuum interlayer is formed between the glass outer tube 1 and the heat collection tube 2. An absorption coating 3 is provided on the outer wall of the heat collection tube 2. A sealing ring 4 is fixedly connected to the end between the glass outer tube 1 and the heat collection tube 2.
[0030] The inner wall of the heat collection tube 2 is provided with a microchannel heat absorption core 5. The top of the microchannel heat absorption core 5 is designed with dense shallow channels to enhance heat absorption, and the bottom is designed with sparse deep channels to reduce flow resistance. The outer end of the glass outer tube 1 is provided with a connecting end tube 11.
[0031] The microchannel heat absorption core 5 is equipped with spiral blades 6.
[0032] Spiral plate 6 is a spiral metal sheet (such as copper / aluminum). The thermal conductivity of the metal sheet is much higher than that of plastic or ceramic, which can quickly transfer heat from the channel wall to the working fluid.
[0033] The end of the heat collection tube 2 near the sealing ring 4 has a corrugated tube 7.
[0034] Bellows 7 is a Kovar alloy transition ring.
[0035] A gap is maintained between the corrugated pipe 7 and the inner wall of the glass outer tube 1.
[0036] The outer wall of the heat collection tube 2 is provided with an annular tube 8 for storing phase change materials.
[0037] The annular tube 8 is made of a light-transmitting material.
[0038] The annular tube 8 contains porous metal foam 9.
[0039] The microporous structure (pore size 0.5-2mm) of porous metal foam 9 can induce micro-convection after the phase change material melts, further enhancing heat transfer.
[0040] When using this new type of vacuum heat collection tube, it is first connected to the external delivery tube through the connecting end tube 11. Then, during operation, water is delivered into the heat collection tube 2 through the external delivery tube. At this time, the water will come into contact with the microchannel heat absorption core 5, and the water flows in from the left end of the heat collection tube 2 and then flows out from the right end of the heat collection tube 2. During this process, since the glass outer tube 1 is located outdoors, sunlight will shine through the glass outer tube 1 onto the absorption coating 3. The absorption coating 3 converts light energy into heat energy, and the heat generated will be directly conducted to the water through the microchannel heat absorption core 5, thereby achieving a heating effect on the water.
[0041] The microchannel heat absorber core 5 greatly increases the heat exchange area, significantly reduces the contact thermal resistance and heat transfer thermal resistance between water and the heat absorber, and improves heat transfer efficiency and response speed, unlike existing technologies. At the same time, since the glass outer tube 1 is usually placed at an angle, there is a sun-facing side and a shaded side when exposed to sunlight. That is, the top of the glass outer tube 1 is the sun-facing side, and the bottom of the glass outer tube 1 is the shaded side. In this case, the top of the microchannel heat absorber core 5 is designed with dense shallow channels to further enhance heat absorption, while the bottom is designed with sparse deep channels to reduce flow resistance. Thus, the design of the microchannel heat absorber core 5 improves the utilization rate of light and reduces pump power loss.
[0042] Next, through the design of the spiral blade 6, when the water flows through the microchannel heat absorption core 5, the spiral blade 6 will destroy the laminar boundary layer, causing the water to become turbulent, thereby achieving a mixing effect on the water. This avoids the situation where the existing single glass structure of the heat collection tube 2 can only heat the part of the water flowing inside that faces the sunlight, while the heating effect on the part of the water that does not face the sunlight is poor, resulting in uneven temperature of the water inside the tube and affecting the heating effect.
[0043] Meanwhile, through the design of the corrugated tube 7, when the heat collector tube 2 is working, the axial expansion difference between the heat collector tube 2 (directly heated) and the glass outer tube 1 (ambient temperature) is caused by the temperature difference. The flexible structure of the corrugated tube 7 avoids the problem of cracking at the glass-metal sealing interface due to stress concentration, which would lead to vacuum failure. At the same time, since there is a gap between the corrugated tube 7 and the inner wall of the glass outer tube 1, it can prevent the glass tube from bending slightly or expanding radially at high temperatures. The gap ensures that the corrugated tube 7 does not come into contact with the inner wall of the glass outer tube 1, preventing friction damage or stress concentration.
[0044] Meanwhile, during the process of converting light energy into heat energy by the aforementioned absorption coating 3, excess solar energy will be absorbed and stored by the phase change material in the annular tube 8, thereby avoiding heat waste. At night or on cloudy days, the heat stored by the phase change material in the annular tube 8 will be released, thereby extending the heating time, solving the problem that traditional vacuum tubes only generate heat when there is sunshine, and improving the system's energy utilization rate. At the same time, the setting of the phase change material in the annular tube 8 can also prevent the phase change material from releasing heat before freezing at low temperatures in areas with large day-night temperature differences, delaying freezing and reducing the risk of tube bursting.
[0045] Meanwhile, the porous metal foam 9 can improve the thermal conductivity, thereby solving the bottleneck of low thermal conductivity of the phase change material itself. It will also absorb the expansion stress generated by the volume expansion or contraction of the phase change material during the melting / solidification process, thus avoiding the expansion stress from causing the annular tube 8 to bulge.
[0046] Furthermore, the porous metal foam 9 effectively absorbs and disperses the volume expansion stress of the phase change material during the melting / solidification process, thereby suppressing the plastic deformation or bulging of the annular tube 8 caused by the phase change of the phase change material.
[0047] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0048] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
Claims
1. A novel vacuum heat collection tube, characterized in that: It includes a glass outer tube (1) and a heat collection tube (2). The heat collection tube (2) is provided inside the glass outer tube (1). A vacuum interlayer is formed between the glass outer tube (1) and the heat collection tube (2). An absorption coating (3) is provided on the outer wall of the heat collection tube (2). A sealing ring (4) is fixedly connected to the end between the glass outer tube (1) and the heat collection tube (2). The inner wall of the heat collection tube (2) is provided with a microchannel heat absorption core (5). The top of the microchannel heat absorption core (5) is designed with dense shallow channels to enhance heat absorption, and the bottom is designed with sparse deep channels to reduce flow resistance. The outer port of the glass outer tube (1) is provided with a connecting end tube (11).
2. The novel vacuum heat collection tube according to claim 1, characterized in that, The microchannel heat absorption core (5) is provided with spiral blades (6).
3. The novel vacuum heat collection tube according to claim 2, characterized in that, The spiral plate (6) is a spiral-shaped metal sheet.
4. The novel vacuum heat collection tube according to claim 1, characterized in that, The heat collection tube (2) has a corrugated tube (7) at one end near the sealing ring (4).
5. The novel vacuum heat collection tube according to claim 4, characterized in that, The bellows (7) is a Kovar alloy transition ring.
6. The novel vacuum heat collection tube according to claim 4, characterized in that, The corrugated tube (7) and the inner wall of the glass outer tube (1) are separated by a gap.
7. The novel vacuum heat collection tube according to claim 1, characterized in that, The outer wall of the heat collection tube (2) is provided with an annular tube (8) for storing phase change materials.
8. The novel vacuum heat collection tube according to claim 7, characterized in that, The annular tube (8) is made of a light-transmitting material.
9. The novel vacuum heat collection tube according to claim 7, characterized in that, The annular tube (8) is provided with porous metal foam (9).
10. The novel vacuum heat collection tube according to claim 9, characterized in that, The micropore diameter of the porous metal foam (9) is 0.5-2 mm.