A vacuum heat collection tube

Abstract

This invention provides a vacuum solar collector tube, comprising an outer vacuum tube, an inner vacuum tube, and a vacuum interlayer therebetween. The vacuum solar collector tube further includes: a solar energy collecting layer disposed on the outer surface of the inner vacuum tube, the solar energy collecting layer comprising a coated area and a non-coated area; and a movable covering unit comprising at least one movable insulating fin disposed outside the non-coated area. Through actual testing, the design of the coated and non-coated areas, as well as the insulating fins in the covering state, of this invention's vacuum solar collector tube effectively acts as a thermal barrier for the vacuum tube, significantly reducing the heat loss coefficient of the collector tube.

Description

Technical Field

[0001] This invention relates primarily to heat collection tubes, and more particularly to a vacuum heat collection tube. Background Technology

[0002] Vacuum collector tubes are a key component of vacuum solar collectors. They are characterized by high heat collection efficiency and low cost, and are widely used in the solar collector market.

[0003] like Figure 1 The image shows a cross-sectional view of a traditional U-shaped cup-shaped vacuum tube with a single-sided opening. This vacuum tube consists of double-layered glass, including an inner glass tube 11 and an outer glass tube 12, with a vacuum interlayer 13 between them. A solar heat-absorbing coating 14 is applied to the outer wall of the inner glass tube 11 within the vacuum interlayer 13 to improve solar radiation absorption. The outer glass tube 12 is a transparent glass tube, with one end closed. The inner and outer glass tubes are coaxial and closed at one end, while the other end is directly fused together. The heat-collecting medium (fluid or gas) enters the tube from the open end 15 to absorb heat. Heat exchange between the tube and the outside is achieved through natural convection of the fluid within the tube.

[0004] Traditional vacuum collector tubes have a blind side, preventing smooth flow of water or other fluids. Heat exchange is limited to inefficient natural convection. Prolonged use also leads to scale buildup inside the tubes, significantly reducing heat transfer performance. Furthermore, factors such as failure to replenish water promptly or failure to drain the tubes at night during winter can cause tube bursts, resulting in unnecessary losses for users and distributors.

[0005] Considering the shortcomings of traditional vacuum collector tubes, heat pipe vacuum collector tubes incorporate auxiliary heat-conducting elements. A heat pipe is a highly efficient heat-conducting element that transfers heat through two phase changes in the working medium. The heat pipe vacuum collector tube developed by combining a heat pipe with a vacuum collector tube has advantages such as high thermal conductivity and good freeze resistance.

[0006] Invention patent application number 200610098390.6 discloses a metal heat pipe type vacuum collector tube, in which a metal heat pipe is inserted into a metal flange and sealed by welding. The metal flange is fused to the glass outer tube opening by Kovar alloy. Although Kovar alloy with a relatively low coefficient of thermal expansion is used, there are still problems with processing. Due to the different coefficients of thermal expansion between metal and glass, gaps are prone to form at the fusion seal during long-term use, making it impossible to guarantee the vacuum level and reducing the efficiency of the collector tube. The use of metal materials increases manufacturing costs, making the price uncompetitive.

[0007] Another type of heat pipe vacuum solar collector uses an all-glass heat pipe structure, such as the all-glass vacuum solar collector disclosed in invention patent number 201210014689.4. The idea is to use a glass heat pipe instead of a metal heat pipe. In the manufacturing process, an all-vacuum glass tube is coaxially extended outward from the ring-sealed cup opening to form the condensing section of the glass heat pipe. Then, a working fluid is injected into the inner tube, and a vacuum is created. The drawbacks are that the ring-sealed area is prone to cracking during actual use due to thermal stress; and because the outer wall of the inner tube is coated with a selective absorption coating before welding the condensing section of the heat pipe, the high temperature can cause the coating at the interface to evaporate, affecting the heat collection effect.

[0008] Due to the introduction of additional materials and processes, heat pipe vacuum collectors employ indirect heat transfer. Although they utilize high thermal conductivity methods, their overall efficiency is still lower than that of direct heat transfer. Therefore, this technology still has significant shortcomings in terms of cost, performance, and reliability, which limits its widespread adoption.

[0009] Straight-through solar collectors with unobstructed flow at both ends can directly collect absorbed solar energy, exhibiting good performance in terms of efficiency and system control through flow regulation. However, current technologies using Kovar metal welded to glass are costly to manufacture, hindering large-scale deployment. Summary of the Invention

[0010] To address the aforementioned problems, this invention creatively solves the challenge of glass tube breakage in straight-through vacuum collector tubes caused by the large temperature difference between the inner and outer tubes at high temperatures, resulting in different expansion and contraction states. Simultaneously, it maintains the high efficiency characteristics of the vacuum collector tube within the target temperature range. This innovative product offers high cost-effectiveness, paving the way for the large-scale application and promotion of straight-through collector tubes.

[0011] The technical problem to be solved by the present invention is to provide a vacuum heat collection tube, comprising a vacuum outer tube, a vacuum inner tube and a vacuum interlayer therebetween, characterized in that the vacuum heat collection tube further comprises:

[0012] A solar collector layer is disposed on the outer surface of the vacuum inner tube, and the solar collector layer includes a coated area and a non-coated area;

[0013] The movable covering unit includes at least one movable heat-insulating fin, which is disposed on the outside of the non-coated area.

[0014] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0015] The coated area and the uncoated area are arranged axially along the outer wall of the vacuum inner tube to form a first and a second sector. The central angle of the first sector of the uncoated area is θ, and the central angle of the second sector of the coated area is 360-θ.

[0016] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0017] The central angle range of the first sector of the non-coated area satisfies: 10°≤θ≤180°.

[0018] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0019] The coated area and the uncoated area are arranged circumferentially along the outer wall of the vacuum inner tube to form a first and a second annular area.

[0020] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0021] The vacuum heat collection tube further includes:

[0022] A reflective unit is disposed between the outer side of the inner vacuum tube and the inner side of the outer vacuum tube in the coating area.

[0023] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0024] The movable heat-insulating fins move radially or circumferentially along the inner vacuum tube.

[0025] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0026] The reflective unit is movably connected to the movable heat-insulating fins, and the movable heat-insulating fins drive the reflective unit to rotate around the circumference of the vacuum inner tube.

[0027] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0028] The vacuum heat collection tube further includes:

[0029] An opening and closing part is disposed within the vacuum interlayer, and the opening and closing part drives the movable heat-insulating fins to open and close relative to the vacuum inner tube.

[0030] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0031] The opening and closing part includes a hinge mechanism, a transmission key, a bimetallic strip, and a bimetallic support. The hinge mechanism includes a hinge shaft and symmetrical movable blades. The bimetallic strip is fixed to the coating area by the bimetallic support. The hinge mechanism and the bimetallic strip are connected by the transmission key.

[0032] When a temperature change occurs, the bimetallic strip springs up or resets, and drives the transmission key to lift or pull back the hinge mechanism, which in turn drives the symmetrical movable blades to open and close, and through the movable blades, drives the movable heat-insulating fins connected to them to open and close.

[0033] Preferably, the present invention further provides a vacuum heat collection tube, characterized in that,

[0034] The opening and closing part includes a shape memory alloy unit, which is connected to the movable heat-insulating fin. When a temperature change occurs, the shape memory alloy unit extends or retracts, causing the movable fin to move.

[0035] Through actual testing, the design of the vacuum heat collection tube of the present invention, through the coated and uncoated areas and the insulation fins in the covered state, acts as a thermal barrier for the vacuum tube and has a significant effect on reducing the heat loss coefficient of the heat collection tube. Attached Figure Description

[0036] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of the invention. In the drawings:

[0037] Figure 1 This is a cross-sectional view of a traditional vacuum heat collection tube;

[0038] Figures 2(1) to 2(4) A perspective view and a cross-sectional view of the first preferred embodiment of the present invention are provided;

[0039] Figure 3(1) and 3(4) The diagram illustrates a perspective view and a cross-sectional view of a second preferred embodiment of the present invention;

[0040] Figure 4(1) and 4(4) These are perspective and sectional views of the third preferred embodiment of the present invention;

[0041] Figure 5(1) and 5(2) These are perspective and sectional views of the fourth preferred embodiment of the present invention;

[0042] Figure 6 This is a perspective view of the fifth preferred embodiment of the present invention;

[0043] Figure 7(1) and 7(2) These are perspective and sectional views of the sixth preferred embodiment of the present invention;

[0044] Figure 8(1) and 8(2) These are perspective and sectional views of the seventh preferred embodiment of the present invention.

[0045] Figure Labels

[0046] 21 — Vacuum outer tube

[0047] 22 — Vacuum Inner Tube

[0048] 23 — Vacuum interlayer

[0049] 24 — Solar collector layer

[0050] 241 — Coating Area

[0051] 242 — Non-coated area

[0052] 25 — Movable Coverage Unit

[0053] 251 — Movable Insulation Fins

[0054] 26 — Reflection Unit

[0055] 27 — Bimetallic strip

[0056] 28 — Bimetallic stent

[0057] 29 — Transmission Key

[0058] 30 — Loose-leaf mechanism

[0059] 301 — Movable blade

[0060] 302 — Loose-leaf roller

[0061] 303 — Moving blades

[0062] 31 — End connection point

[0063] 32 — Shape Memory Alloy Unit

[0064] 200 — Opening and Closing Section Detailed Implementation

[0065] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0066] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0067] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0068] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms 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 on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0069] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0070] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0071] Flowcharts are used in this application to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0072] Example 1

[0073] Figures 2(1) to 2(4) The structure of the first preferred embodiment of this case is given.

[0074] The vacuum heat collection tube in this embodiment 1 includes a vacuum outer tube 21, a vacuum inner tube 22, and a vacuum interlayer 23 between them. The outer surface of the vacuum inner tube 22 is a solar heat collection layer 24, which is a selective absorption coating on the outer wall of the vacuum inner tube 22.

[0075] From the cross-sectional view in Figure 2(2), the heat collection layer 24 does not completely cover the outer wall of the vacuum inner tube 22, but only partially covers it. The coated area 241 and the uncoated area 242 are arranged along the axial direction of the outer wall of the vacuum inner tube, forming two fan-shaped areas. The central angle corresponding to the fan-shaped area of ​​the uncoated area 242 is shown as θ, and the central angle corresponding to the fan-shaped area of ​​the coated area 241 is (360-θ). The following conditions must be met:

[0076] 10°≤θ≤180°

[0077] A movable covering unit 25 is provided in the non-coated area 242. In a preferred embodiment, the movable covering unit 25 includes at least one movable heat-insulating fin 251 that slides open and closes. In the illustrated embodiment, there are two fins. The fins 251 can be attached to the outer circumferential surface of the non-coated area 242 or can be spaced apart. The movable heat-insulating fin 251 slides open and closes circumferentially along the outer wall of the vacuum inner tube 22. Figure 2(1) shows a cross-sectional view of the movable heat-insulating fin 251 completely covering the non-coated area 242 and sliding open in the direction of the arrow. Figure 2(2) is a perspective view of the corresponding vacuum heat collection tube.

[0078] Figure 2(3) is a schematic diagram of the movable heat-insulating fin 251 sliding from the coated area 241 back to the non-coated area 242 in the direction of the arrow and covering the non-coated area 242.

[0079] Figure 2(4) is a cross-sectional view of Figure 2(3). The arrows indicate that the movable heat-insulating fins 251 slide to close the non-coated area 242.

[0080] In the above embodiment, the coated area 241 of the solar collector layer 24 is arranged on the outer surface of the vacuum inner tube 22 with a central angle of no more than 350° in the fan-shaped area. For the outer side of the non-coated area 242 with a central angle of no more than 180° in the fan-shaped area, a movable covering unit 25 is used. Once the temperature of the vacuum inner tube 22 of the vacuum collector tube is too high, or the temperature difference between the vacuum inner tube 22 and the vacuum outer tube 21 is too large, the movable covering unit 25 moves to expose the non-coated area 242 of the vacuum inner tube 22, thereby dissipating heat, controlling the temperature of the vacuum inner tube 22, and protecting the vacuum collector tube.

[0081] In actual measurements, the solar collector layer 24 provides excellent insulation when the collector tube is in heat absorption mode. The measured heat loss coefficient of this structure is approximately 20% lower than that of a conventional vacuum collector tube. This demonstrates superior insulation performance, thus significantly improving heat collection efficiency.

[0082] In a comparative test under high-temperature protection conditions, the maximum temperature of the vacuum inner tube 22 with the exposed covered portion of the structure was more than 40 degrees Celsius lower than that of a conventional vacuum collector tube. In a test with solar radiation reaching 1000 watts per square meter, a conventional vacuum collector tube shattered, while the vacuum collector tube using the structure of this invention remained intact.

[0083] Example 2

[0084] Figures 3(1) to 3(4) The second preferred embodiment of this case is presented.

[0085] The basic structure of this embodiment is similar to that of embodiment 1. The vacuum heat collection tube includes a vacuum outer tube 21, a vacuum inner tube 22, and a vacuum interlayer 23 between them. The outer surface of the vacuum inner tube 22 is a solar heat collection layer 24. The heat collection layer 24 includes two fan-shaped coated areas 241 and non-coated areas 242. The non-coated area 242 is provided with at least one movable heat-insulating fin 251 that can be slidably opened and closed.

[0086] Unlike Embodiment 1, a reflective unit 26, fixed by a bracket, is added inside the vacuum interlayer 23. As shown in the figure, the two ends of the reflective unit 26 are respectively located on the outside of the inner vacuum tube 22 and the inside of the outer vacuum tube 21, thereby dividing the vacuum interlayer 23 into two regions, with all coating areas 241 located within the same region separated by the reflective unit 26.

[0087] In this embodiment, another mode of movement for the movable heat-insulating fins 251 is also provided, namely, radial opening and closing movement. Figure 3(1) and 3(2) The diagram shows the movable insulation fin 251 unfolding rather than sliding. The arrows indicate the radial outward movement and unfolding of the insulation fin 251.

[0088] Figure 3(3) and 3(4) The diagram shows the movable insulation fins 251 closing in a way that is not sliding. The arrows indicate the radial inward movement and closing of the insulation fins 251.

[0089] Similar to the working principle of Example 1, the movable covering structure composed of movable insulation fins 251 can increase heat dissipation and control temperature by radially moving to expose the outer surface of the covered inner tube when the temperature of the inner tube is too high or the temperature difference between the inner tube and the outer tube is too large.

[0090] Example 3

[0091] Figures 4(1) to 4(4) The third preferred embodiment structure of this case is presented.

[0092] This embodiment is similar in structure to Embodiment 2, with a reflective unit 26 added within the vacuum interlayer 23 of the vacuum collector tube. The difference is that the reflective unit 26 is not fixedly positioned between the outer vacuum tube 21 and the inner vacuum tube 22, but is linked to the movable covering unit 25. When the temperature of the inner vacuum tube 22 is too high, or the temperature difference between the inner vacuum tube 22 and the outer vacuum tube 21 is too large, as shown in Figures 4(3) and 4(4), the movable insulating fins 251 of the movable covering unit 25 open, exposing the non-coated area 242 on the outer surface of the covered inner vacuum tube 22 to increase heat dissipation and control the temperature. During this opening process, the reflective unit 26 moves around the inner vacuum tube 22, thereby reducing the solar reflection absorption area. When the temperature drops or the temperature difference is small, as shown in Figures 4(1) and 4(2), the movable insulating fins 251 return to their original position.

[0093] Example 4

[0094] Figures 5(1) to 5(2) The structure of the fourth preferred embodiment of this case is given.

[0095] The significant difference between this embodiment and the previous embodiment is that the movable heat-insulating fin 251 used in the movable covering unit 25 is a single-fin structure. This single fin 251 can slide circumferentially on the outer wall of the vacuum inner tube 22, that is, it can slide between the coated area 241 and the uncoated area 242 of the solar collector layer 24, depending on the actual situation.

[0096] When the temperature of the inner vacuum tube 22 is too high, or the temperature difference between the inner vacuum tube 22 and the outer vacuum tube 21 is too large, the non-coated area 242 of the outer surface of the covered inner vacuum tube 22 is opened to increase heat dissipation and control the temperature. When the temperature or temperature difference decreases, the single fin 251 returns to the position covering the non-coated area 242.

[0097] Example 5

[0098] The aforementioned embodiments all involve structures where the movable heat-insulating fins 251 slide circumferentially within the vacuum inner tube 22, or move radially about an axis. Figure 6 The embodiment shown employs a structure that moves along the axial direction.

[0099] Specifically, the coated area 241 and the non-coated area 242 on the solar collector layer 24 on the outer surface of the vacuum inner tube 22 are arranged in annular intervals along the circumference of the outer wall of the vacuum inner tube. In other words, the coated area 241 adopts annular coating, that is, the coated area 241 and the non-coated area 242 are interspersed in annular intervals on the outer surface of the vacuum inner tube 22. In this way, when the temperature of the vacuum inner tube 22 is too high, or the temperature difference between the vacuum inner tube 22 and the vacuum outer tube 21 is too large, the movable heat insulation fins 251 can slide axially as needed to open the non-coated area 242 of the covered outer surface of the vacuum inner tube 22 to increase heat dissipation and control the temperature. When the temperature or temperature difference decreases, the movable heat insulation fins 251 return to cover the non-coated area 242.

[0100] Example 6

[0101] Figure 7(1) and 7(2) The structure of the sixth preferred embodiment of this case is further illustrated.

[0102] The solar collector tube consists of a vacuum outer tube 21, a vacuum inner tube 22, and a vacuum interlayer 23 between the inner and outer tubes.

[0103] In the vacuum jacket 23, there is an opening and closing part 200, through which the movable heat-insulating fins 251 are opened or closed, ultimately realizing the heat collection tube in heat dissipation and temperature control state or heat collection and heat preservation state.

[0104] The opening and closing part 200 includes a hinge mechanism 30, a transmission key 29, and a bimetallic strip 27. Its structure is described in detail below.

[0105] A bimetallic strip 27 is used to sense the temperature of the outer wall of the inner tube and is fixed by a bimetallic bracket 28. The bimetallic strip 27 springs up or resets when the temperature rises or falls to a certain threshold. The bimetallic strip 27 is connected to a transmission key 29, which can lift or pull back the hinge mechanism 30 it contacts during the springing or resetting action of the bimetallic strip 27. The hinge mechanism 30 includes a hinge shaft 302 and symmetrical movable blades 301 and 303 on both sides.

[0106] The hinge mechanism 30 opens or closes around the hinge shaft 302 when the drive key 29 lifts or pulls back the hinge. This opening or closing causes the movable blades 301 and 303 to open or close, and the movable blades 301 and 303 also drive the movable heat-insulating fins 251 connected to their end connection points 31 to open or close.

[0107] The hinge shaft 302 has a support structure (not shown) consisting of support holes or support grooves at both ends or one end, which is fixed to the outer wall surface of the vacuum inner tube 22.

[0108] The bimetallic strip 27 is connected to the transmission key 29, and the connection can be achieved by welding, riveting, or other processes. When heated, the bimetallic strip 27 expands and contracts due to heat, changing from the state shown in Figure 7(1) to the state shown in Figure 7(2). It will protrude outward and push the transmission key 29 outward, thereby actuating the hinge shaft 302 to open the movable blades 301 and 303 on both sides, realizing the angle change of the movable blades 301 and 303 around the hinge shaft 302. This achieves the heat dissipation and temperature control state or the heat collection and heat preservation state of the heat collection tube.

[0109] In addition, a rotatable reflective unit 26 can be movably connected to the end connection point 31 of the movable blades 301 and 303. The reflective surface of the reflective unit 26 has an angle of 45° to 60° with the vertical direction. Thus, the reflective unit 26 can rotate to a protective angle state that reduces sunlight reflection and an optimized heat absorption state that increases sunlight reflection during the opening or closing of the movable blades 301 and 303.

[0110] Example 7

[0111] Figure 8(1) and 8(2) The structure of the seventh preferred embodiment of this case is further illustrated.

[0112] In a solar collector tube with a structure similar to that of Embodiment 1, a different type of opening and closing part 200 is used in the vacuum interlayer 23.

[0113] The opening / closing part 200 includes a shape memory alloy unit 32, which is an extendable strip and connected to movable heat-insulating fins 251 on both sides by means of riveting or other methods. The shape memory alloy unit 32 itself has the characteristic of contracting or expanding when a certain temperature threshold is reached, which can drive the heat-insulating fins 251 to cover the coating area 241, so that the movable fins 251 avoid the high radiation area of ​​the glass tube, enhance heat dissipation, and achieve the protection function of controlling the maximum temperature.

[0114] Figure 8(1) illustrates the state where the shape memory alloy unit 32 is about to extend outward from its original curved shape when it absorbs heat to a certain extent. Figure 8(2) shows the shape memory alloy unit 32 retracting and resetting after the temperature or temperature difference decreases. In the case shown in Figure 8(1), during the straightening and elongation process, the shape memory alloy unit 32 pushes the movable fins 251 from the non-coated area 242 to the coated area 241, which plays a shielding role.

[0115] In summary, this application achieves high heat collection efficiency and optimized high-temperature protection by arranging coated and uncoated areas on the outer wall of the existing vacuum heat collection tube. Movable insulation fins are then added to this arrangement. This optimization of the coated and uncoated areas, along with the covering and opening of the insulation fins in the uncoated area, achieves both high heat collection efficiency and optimized high-temperature protection.

[0116] Compared with the prior art, the present invention has the following advantages:

[0117] First, high reliability: Bimetallic strips are widely used in the aerospace industry and vacuum environments. The triggering is determined by the material properties and structure, and the repeatability is good.

[0118] Secondly, it is low-cost: the bimetallic strips and insulation fins considered in this structure have low material costs and simple manufacturing processes for large-scale applications, thus providing extremely high cost-effectiveness.

[0119] Third, high efficiency: Through actual testing, the insulation fins, when covered, act as a thermal barrier for the vacuum tube, which has a significant effect on reducing the heat loss coefficient of the heat collection tube.

[0120] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0121] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0122] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0123] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0124] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0125] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0126] Although this application has been described with reference to specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate this application, and various equivalent changes or substitutions can be made without departing from the spirit of this application. Therefore, any changes or modifications to the above embodiments within the essential spirit of this application will fall within the scope of the claims of this application.

Claims

1. A vacuum heat collection tube, comprising an outer vacuum tube, an inner vacuum tube, and a vacuum interlayer therebetween, characterized in that, The vacuum heat collection tube further includes: A solar collector layer is disposed on the outer surface of the vacuum inner tube, and the solar collector layer includes a coated area and a non-coated area; A movable covering unit includes at least one movable heat-insulating fin, which is disposed on the outside of the non-coated area; When the temperature of the inner vacuum tube of the vacuum collector exceeds the set temperature, or the temperature difference between the inner vacuum tube and the outer vacuum tube is greater than the set temperature, the movable covering unit moves to expose the non-coated area of ​​the inner vacuum tube.

2. The vacuum heat collection tube according to claim 1, characterized in that, The coated area and the uncoated area are arranged axially along the outer wall of the vacuum inner tube to form a first and a second sector. The central angle of the first sector of the uncoated area is θ, and the central angle of the second sector of the coated area is 360°-θ.

3. The vacuum heat collection tube according to claim 2, characterized in that, The central angle range of the first sector of the non-coated area satisfies: 10°≤θ≤180°.

4. The vacuum heat collection tube according to claim 1, characterized in that, The coated area and the uncoated area are arranged circumferentially along the outer wall of the vacuum inner tube to form a first and a second annular area.

5. The vacuum heat collection tube according to claim 3, characterized in that, The vacuum heat collection tube further includes: A reflective unit is disposed between the outer side of the inner vacuum tube and the inner side of the outer vacuum tube in the coating area.

6. The vacuum heat collection tube according to claim 5, characterized in that, The movable heat-insulating fins move radially or circumferentially along the inner vacuum tube.

7. The vacuum heat collection tube according to claim 6, characterized in that, The reflective unit is movably connected to the movable heat-insulating fins, and the movable heat-insulating fins drive the reflective unit to rotate around the circumference of the vacuum inner tube.

8. The vacuum heat collection tube according to claim 6, characterized in that, The vacuum heat collection tube further includes: An opening and closing part is disposed within the vacuum interlayer, and the opening and closing part drives the movable heat-insulating fins to open and close relative to the vacuum inner tube.

9. The vacuum heat collection tube according to claim 8, characterized in that, The opening and closing part includes a hinge mechanism, a transmission key, a bimetallic strip, and a bimetallic support. The hinge mechanism includes a hinge shaft and symmetrical movable blades. The bimetallic strip is fixed to the coating area by the bimetallic support. The hinge mechanism and the bimetallic strip are connected by the transmission key. When a temperature change occurs, the bimetallic strip springs up or resets, and drives the transmission key to lift or pull back the hinge mechanism, which in turn drives the symmetrical movable blades to open and close, and through the movable blades, drives the movable heat-insulating fins connected to them to open and close.

10. The vacuum heat collection tube according to claim 8, characterized in that, The opening and closing part includes a shape memory alloy unit, which is connected to the movable heat-insulating fin. When a temperature change occurs, the shape memory alloy unit extends or retracts, causing the movable fin to move.

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