Non-tracking solar collectors

Abstract

The present invention discloses a non-tracking solar collector, comprising a shell, and a U-shaped heat-conducting metal tube, a heat-absorbing film plate, a shielding and reflecting component, a bracket and a ceramic heat-insulating assembly located in the shell, wherein the open end of the U-shaped heat-conducting metal tube is connected to the shell; the heat-absorbing film plate is arranged on the U-shaped heat-conducting metal tube; the shielding and reflecting component and the heat-absorbing film plate form a cavity, and the main body of the U-shaped heat-conducting metal tube is enclosed in the cavity; the bracket comprises a first bracket and a second bracket for matching use, the first bracket is arranged between the shell and the heat-absorbing film plate, the second bracket is arranged between the shielding and reflecting component and the shell, and the first bracket, the second bracket, the heat-absorbing film plate and the shielding and reflecting component are all provided with holes, and are connected to the ceramic heat-insulating assembly by bolts. The collector of the present invention has a simple structure and less radiant heat loss.

Description

Technical Field

[0001] The invention relates to the field of solar energy technology, and in particular to a non-tracking solar thermal collector. Background Art

[0002] In the thermal utilization of solar energy, the key is to convert the solar radiation energy into thermal energy. Since solar energy is relatively dispersed, it must be concentrated. Solar collectors are devices used to absorb solar radiation, convert it into thermal energy and transfer it to heat media. Although it is not a terminal product directly facing consumers, solar collectors are key components of various solar thermal utilization systems. Whether it is a solar water heater, solar cooker, active solar house, solar greenhouse, solar drying, solar industrial heating, solar thermal power generation, etc., they are inseparable from solar collectors, and they all use solar collectors as the power or core components of the system. Common types include flat-plate, vacuum tube and concentrating solar collectors.

[0003] Vacuum tube solar collectors often use all-glass vacuum tube heat collection tubes, which are composed of two inner and outer glass tubes. A vacuum cavity is formed between the inner and outer tubes. The outer surface of the inner tube is provided with a solar selective absorption coating, and the heat transfer medium (water) is transmitted in the inner tube. In the prior art, multiple parallel heat collection tubes are often arranged in the glass tube. These heat collection tubes are connected in parallel to the confluence trough and connected to the mother tube through a reducer. Usually, the heat collection tube adopts a U-shaped capillary tube, and the surface of these U-shaped capillary tubes is mostly coated with a selective absorption coating. The manufacturing process is complicated, and the parallel connection of multiple U-shaped capillary tubes in order to obtain a larger heat absorption area makes the structure of the heat collection tube complicated, and the manufacturing and installation costs are relatively high.

[0004] Therefore, there is an urgent need in the art to develop a solar collector tube that has a simple structure, is easy to manufacture, and has low cost, high heat absorption efficiency, low thermal emissivity, and high operating temperature. Summary of the invention

[0005] The object of the present invention is to provide a heat collector with simple structure, convenient manufacture, low cost, long service life and high heat collection efficiency.

[0006] To achieve the above object, the present invention provides a heat collector, comprising: a shell, and a U-shaped heat-conducting metal tube, a heat-absorbing film plate, a shielding and reflecting component, a bracket and a ceramic heat-insulating component located in the shell, wherein:

[0007] The open end of the U-shaped heat-conducting metal tube is connected to the shell;

[0008] The heat absorbing film plate is arranged on the U-shaped heat conducting metal tube;

[0009] The shielding and reflecting component and the heat absorbing film plate form a cavity, and the U-shaped heat-conducting metal tube body is enclosed in the cavity;

[0010] The bracket includes a first bracket and a second bracket used in conjunction with each other, the first bracket is placed between the shell and the heat absorbing film plate, and the second bracket is placed between the shielding and reflecting component and the shell.

[0011] The first bracket, the second bracket, the heat absorbing film plate and the shielding and reflecting component are all provided with holes and are connected to the ceramic heat insulation assembly by bolts.

[0012] In another preferred embodiment, the open end of the U-shaped heat-conducting metal tube is connected to the shell through a Kovar alloy end cap.

[0013] In another preferred example, the distance between the shielding and reflecting component and the U-shaped heat-conducting metal tube is 0.8-1.5 mm or 1-1.2 mm.

[0014] In another preferred example, the distance between the shielding and reflecting component and the heat absorbing film plate is 0.8-1.5 mm or 1-1.2 mm.

[0015] In another preferred embodiment, the shielding reflection component is a groove type, comprising a main body, an extension portion, a first baffle and a second baffle, wherein:

[0016] The main body is a flat plate, which is placed under the U-shaped heat-conducting metal tube, and a plurality of holes (such as 1-8, preferably 2-6 or 3-5 holes) are arranged on the flat plate for placing the ceramic heat-insulating assembly;

[0017] The two ends of the flat plate extend outward to form an extension portion outside the heat absorbing film plate;

[0018] The first baffle and the second baffle are respectively arranged at two ends of the shielding and reflecting component, and form a groove with the main body and the extending part.

[0019] Wherein, two notches are arranged on the second baffle plate for the U-shaped heat-conducting metal tube to pass through.

[0020] In another preferred embodiment, the shell includes an integrally formed glass tube and a glass seal, and the glass seal is in a constant curvature form.

[0021] Firing the glass head into a constant curvature form can reduce the stress of the glass head and reduce the breakage rate of the head.

[0022] In another preferred embodiment, the first bracket includes a first bracket crossbeam and two first curved portions extending upward from two ends of the first bracket crossbeam;

[0023] The second bracket includes a second bracket cross beam and two second curved portions extending upward from two ends of the second bracket cross beam.

[0024] The first support beam is arranged between the shell and the heat absorbing film plate, the second support beam is arranged between the shielding and reflecting component and the shell, and the two first bent portions and the two second bent portions are both stuck to the inner side of the shell.

[0025] In another preferred example, the first support beam and / or the second support beam is a hollow structure.

[0026] In another preferred embodiment, the ceramic thermal insulation assembly includes two ceramic washers, a long ceramic column and two short ceramic columns, wherein:

[0027] The ceramic long column is a column with a through hole, and its two ends are respectively against the heat absorbing film plate and the shielding and reflecting component;

[0028] The two ceramic washers are washers each having a through hole, and are respectively arranged on the first bracket and the second bracket;

[0029] The two ceramic short columns are step short columns, including a first column and a second column that are integrally formed and both have through holes, the first columns of the two ceramic short columns are respectively placed in the holes of the heat absorbing film plate and the shielding and reflecting component, and the second columns of the two ceramic short columns are respectively arranged between the first bracket and the heat absorbing film plate, and between the shielding and reflecting component and the second bracket; the diameter of the through hole of the first column is smaller than the diameter of the through hole of the second column;

[0030] The through holes of the two ceramic washers have the same diameter as the through holes of the first cylinders of the two ceramic short cylinders; the through holes of the ceramic long cylinder have the same diameter as the through holes of the second cylinders of the two ceramic short cylinders;

[0031] The bolts pass through the through holes to connect the first bracket, the heat absorbing film plate, the shielding and reflecting component and the second bracket.

[0032] In another preferred embodiment, the number of the brackets is N, the number of the ceramic thermal insulation components is 2N, and N is 1-5 or 1-3 or 2-3.

[0033] In another preferred example, the shell includes a light-facing surface and a back-light surface; the heat-absorbing film plate is installed between the light-facing surface of the shell and the U-shaped heat-conducting metal tube, and the side of the heat-absorbing film plate facing the light-facing surface of the shell is coated with a selective absorption coating, and the other side of the heat-absorbing film plate is tightly fitted with the U-shaped heat-conducting metal tube.

[0034] The heat collector of the present invention is provided with a heat absorbing film plate, which is coated with a selective absorption coating with high solar absorption efficiency and low reflection efficiency. The surface area of ​​the heat absorbing film plate is large, and the heat absorbed by the heat absorbing film plate can be quickly transferred to the U-shaped heat-conducting metal tube and the shielding reflection component, which is used to reduce the heat radiation loss of the heat collector. In addition, the heat collector of the present invention can be provided with only one U-shaped heat-conducting metal tube, so that the structure of the heat collector is simplified, the manufacturing process and cost are low, and the installation is convenient.

[0035] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein can be applied to the methods of the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only.

[0036] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as embodiments) can be combined with each other to form a new or preferred technical solution. Due to space limitations, they will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the three-dimensional structure of the collector according to an embodiment of the present invention.

[0038] Figure 2 It is a schematic diagram of the cross-sectional structure of a heat collector according to an embodiment of the present invention.

[0039] Figure 3 It is a schematic diagram of the three-dimensional structure of the shielding reflection component.

[0040] Figure 4 It is a schematic diagram of the three-dimensional structure of the bracket.

[0041] Figure 5 It is a schematic diagram of the three-dimensional structure of the ceramic insulation component, wherein a is a ceramic gasket; b is a ceramic short column; and c is a ceramic long column. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings so that the purpose, features and advantages of the present invention can be more clearly understood. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0043] like Figure 1 and Figure 2 As shown, the heat collector of the present invention comprises a shell 1, and a U-shaped heat-conducting metal tube 2, a heat-absorbing film plate 3, a shielding and reflecting component 4, a bracket 5 and a ceramic heat-insulating component 6 located in the shell 1.

[0044] The shell 1 includes an integrally formed glass tube and a glass seal head, wherein the glass seal head is in a constant curvature form. Sintering the glass seal head into a constant curvature form can reduce the stress of the glass seal head and reduce the breakage rate of the seal head.

[0045] In a preferred embodiment, the housing 1 is made of borosilicate glass.

[0046] The open end of the U-shaped heat-conducting metal tube 2 is connected to the shell 1 through a Kovar alloy end 7 .

[0047] The heat absorbing film plate 3 is arranged on the U-shaped heat conducting metal tube 2 .

[0048] The heat collector of the present invention may only have one slender U-shaped heat-conducting metal tube, the outer diameter of which is 5-10 mm, preferably 8 mm, and the wall thickness of which is 0.3 mm-0.7 mm, preferably 0.5 mm.

[0049] The housing 1 includes a light-facing surface and a backlight surface. The heat-absorbing film plate 3 is installed between the light-facing surface of the housing 1 and the U-shaped heat-conducting metal tube 2, and the side of the heat-absorbing film plate 3 facing the light-facing surface of the housing 1 is coated with a selective absorption coating, and the other side of the heat-absorbing film plate 3 is tightly fitted with the U-shaped heat-conducting metal tube 2.

[0050] In another preferred embodiment, the housing is cylindrical or elliptical, and the cylindrical or elliptical housing is divided into two parts, a light-facing surface and a backlight surface, by a plane passing through its central axis. In another preferred embodiment, the light-facing surface is transparent.

[0051] In another preferred embodiment, the outer side wall of the light-facing surface is coated with an anti-reflection film, and the anti-reflection film is used to increase the incidence of sunlight.

[0052] In another preferred embodiment, a shielding and reflecting component is provided on the inner side wall of the backlight surface, and the shielding and reflecting component is used to reduce the heat radiation loss of the collector.

[0053] A closed vacuum environment can be formed inside the shell 1 , and sunlight is irradiated onto the heat absorbing film plate 3 through the light-facing surface of the shell 1 . The heat absorbed by the heat absorbing film plate 3 is used to heat the heat transfer medium in the U-shaped heat collecting tube 2 .

[0054] In a preferred embodiment, the shielding and reflecting component is an aluminum plate or a silver plate or an aluminum-plated stainless steel plate fixed to the inner side wall of the backlight surface.

[0055] In a preferred embodiment, the metal reflective layer is silver foil or aluminum foil.

[0056] In another preferred example, the pipeline on the outside of the shell and sealedly connected to the U-shaped heat-conducting metal pipe in the shell is wrapped with insulation material, or the pipeline is a vacuum insulation pipe.

[0057] In another preferred embodiment, the shell is filled with evaporable and non-evaporable getters for maintaining the vacuum degree in the shell.

[0058] The U-shaped heat-conducting metal tube 2 is a slender U-shaped tube, and the U-shaped tube has a plane that fits with the heat-absorbing film plate, thereby increasing the contact area between the U-shaped heat collecting tube and the heat-absorbing film plate and improving the heat transfer efficiency.

[0059] In another preferred embodiment, the surface of the U-shaped heat-conducting metal tube is polished / aluminum-plated or other related processes to reduce the surface emissivity to 2% or less.

[0060] Although not shown in the figure, preferably, the U-shaped heat-conducting metal tube 2 has a plane that fits with the heat-absorbing film plate 3, so that the contact area between the U-shaped heat-conducting metal tube 2 and the heat-absorbing film plate 3 can be increased, and the heat transfer efficiency can be improved. The heat-absorbing film plate 3 can be fixedly connected to the U-shaped heat-conducting metal tube 2 through a bracket, and can also be bonded to the U-shaped heat-conducting metal tube 2 through an adhesive.

[0061] In another preferred example, the size of the heat absorbing film plate is 134 mm×1880 mm.

[0062] The selective absorption coating coated on the side of the light-facing surface of the heat absorption film plate 3 facing the shell 1 can be composed of materials such as semiconductor absorption-metal reflection series list surface, metal-dielectric composite material, dielectric-metal interference laminated surface, intrinsic selective absorption surface or micro-rough surface. The selective absorption coating is a high absorption rate, low emissivity selective absorption material. Semiconductor absorption-metal reflection series list surface can be selected from Si / Ge / -Al / Au / Cu / Al / Pt / W / Ni and other materials. Metal-dielectric composite material can be selected from Pt-Al2O3, Ni-SiO2, Ni / Co / Mo / Au / W / Pt-Al2O3, Al-AlN; Mo-MoO2 or W-WO2 and other materials. Dielectric-metal interference laminated surface can be selected from ZrB2, Mo / Co / Cr-Cr2O3, Mo-AlN or Au-TiO2 / MgO and other materials. Intrinsic absorption selective absorption surface W, HfC or Cu2S and other materials. The micro-rough surface can be made of materials such as Cu, Ni, SS, Re or W. In this embodiment, the selective absorption coating is composed of a metal reflective layer and a semiconductor absorption layer formed on the metal reflective layer. The metal reflective layer material is Ge, and the semiconductor absorption layer material is Al. The selective absorption coating plated on the outer surface of the U-shaped heat-conducting metal tube is used to absorb sunlight visible light, reduce infrared radiation, improve the absorption efficiency of sunlight, reduce radiation efficiency, and thus increase the working temperature of the U-shaped heat-conducting metal tube.

[0063] like Figure 2 and Figure 3 As shown, the shielding reflection component 4 is a groove type, including a main body 41, an extension portion 42, a first baffle 43 and a second baffle 44, wherein:

[0064] The main body 41 is a flat plate, which is placed below the U-shaped heat-conducting metal tube 2, and a plurality of holes 45 are provided on the flat plate for placing the ceramic heat-insulating assembly 6;

[0065] The two ends of the flat plate extend outward to form an extension portion 42 outside the heat absorbing film plate 3;

[0066] The first baffle plate 43 and the second baffle plate 44 are respectively disposed at two ends of the shielding reflection component 4, and form a groove with the main body 41 and the extension portion 44.

[0067] The second baffle plate 44 is provided with two notches 46 for the U-shaped heat-conducting metal tube 2 to pass through.

[0068] The shielding and reflecting component 4 and the heat absorbing film 3 form a cavity, and the main body of the U-shaped heat-conducting metal tube 2 is enclosed in the cavity.

[0069] In the present invention, the shielding and reflecting component and the heat absorbing film plate form a cavity, which completely encloses the back of the heat absorbing film plate and the heat-conducting metal tube, thereby reducing radiation heat loss.

[0070] In the present invention, both sides of the shielding and reflecting component are aluminum-plated / mirror-polished to reduce the surface emissivity of the material to 2% or less.

[0071] In the present invention, in order to avoid contact heat conduction, the shielding and reflecting component maintains a distance of 0.8-1.5 mm from the U-shaped heat-conducting metal tube; the shielding and reflecting component maintains a distance of 0.8-1.5 mm from the heat-absorbing film plate.

[0072] like Figure 1 and Figure 2 As shown, the bracket 5 includes a first bracket 51 and a second bracket 52 used in conjunction with each other, the first bracket 51 is placed between the shell 1 and the heat absorbing film plate 3, and the second bracket 52 is placed between the shielding and reflecting component 4 and the shell 1.

[0073] The first bracket 51 , the second bracket 52 , the heat absorbing film plate 3 and the shielding and reflecting component 4 are all provided with holes and are connected to the ceramic heat insulation component 6 via bolts 8 and nuts 9 .

[0074] The first bracket 51 and the second bracket 52 have the same structure, and the structure is described by taking the first bracket 51 as an example. Figure 4 As shown, the first bracket 51 includes a first bracket crossbeam 53 and two first curved portions 54 extending upward from both ends of the first crossbeam 53; similarly, the second bracket includes a second bracket crossbeam and two second curved portions extending upward from both ends of the second crossbeam.

[0075] Among them, Figure 2 As shown, the first support beam 53 is arranged between the shell 1 and the heat absorbing film plate 3, the second support beam is arranged between the shielding and reflecting component 4 and the shell 1, and the two first bending parts 54 and the two second bending parts are both stuck on the inner side of the shell 1.

[0076] like Figure 4 As shown, the first support beam and / or the second support beam are / is a hollow structure.

[0077] In the present invention, the first support beam and the second support beam are arranged as hollow structures, so as to reduce the shielding loss of the heat absorbing film plate surface and reduce the heat conduction loss from the support to the glass shell.

[0078] In the present invention, the bracket is made of low outgassing material (metal or other), and the first bracket and the second bracket are used in combination to fix the heat absorbing film plate, shielding and reflecting component, U-shaped heat-conducting metal tube, and ceramic insulation component inside the shell by bolts and nuts.

[0079] like Figure 2 and 5 As shown, the ceramic heat insulation assembly 6 of the present invention includes two ceramic washers 61, a ceramic long column 63 and two ceramic short columns 62, wherein:

[0080] The ceramic long column 63 is a column with a through hole, and its two ends respectively abut against the heat absorbing film plate 3 and the shielding and reflecting component 4, specifically, against the main body 41 of the shielding and reflecting component 4;

[0081] The two ceramic washers 61 are washers with a through hole, and are respectively arranged on the first bracket 51 and the second bracket 52;

[0082] The two ceramic short columns 62 are step short columns, including a first column 64 and a second column 65 which are integrally formed and both have through holes. The first columns 64 of the two ceramic short columns are respectively placed in the holes of the heat absorbing film plate 3 and the shielding and reflecting component 4, specifically the main body 41. The second columns 65 of the two ceramic short columns are respectively arranged between the first bracket 51 and the heat absorbing film plate 3, and between the shielding and reflecting component 4 and the second bracket 52; the diameter of the through hole of the first column 64 is smaller than the diameter of the through hole of the second column 65;

[0083] The through holes of the two ceramic washers 61 have the same diameter as the through holes of the first columns 64 of the two ceramic short columns 62; the through holes of the ceramic long columns 63 have the same diameter as the through holes of the second columns 65 of the two ceramic short columns 62;

[0084] The bolts 8 pass through the through holes to connect the first bracket 51, the heat absorbing film plate 3, the shielding and reflecting component 4 and the second bracket 52, and cooperate with the nuts 9 to perform fixed connection.

[0085] The through holes of the two ceramic washers and the through holes of the first columns of the two ceramic short columns match the bolts.

[0086] In the present invention, a ceramic heat insulation assembly is used to isolate the bolts from the first bracket, the heat absorbing film plate, the shielding and reflecting component, and the second bracket, thereby reducing the heat conducted by the heat absorbing film plate to the shielding and reflecting component, the first bracket, and the second bracket through the bolts.

[0087] In the collector of the present invention, the number of the brackets is N, the number of the ceramic thermal insulation components is 2N, and N is 1-5.

[0088] In order to maintain the vacuum degree in the collector shell, evaporable and non-evaporable getters for maintaining the vacuum degree in the shell can be filled in the shell. In addition, the outer side of the sealing sleeve can be wrapped with insulation material, or a vacuum insulation sleeve can be set to reduce heat loss and improve the working efficiency of the collector.

[0089] The heat collector of the present invention is provided with a heat absorbing film plate, which is coated with a selective absorption coating with high solar absorption efficiency and low reflection efficiency. The surface area of ​​the heat absorbing film plate is large, and the heat absorbed by the heat absorbing film plate can be quickly transferred to the U-shaped heat-conducting metal tube and the heat radiation shielding layer, which is used to reduce the heat radiation loss of the heat collector. In addition, the heat collector of the present invention can be provided with only one U-shaped heat-conducting metal tube, so that the structure of the heat collector is simplified, the manufacturing process and cost are low, and the installation is convenient.

[0090] The preferred embodiments of the present invention have been described in detail above, but it should be understood that after reading the above teachings of the present invention, those skilled in the art may make various changes or modifications to the present invention. These equivalent forms also fall within the scope defined by the appended claims of this application.

Claims

1. A heat collector, characterized in that: The collector comprises: a shell, and a U-shaped heat-conducting metal tube, a heat-absorbing film plate, a shielding and reflecting component, a bracket and a ceramic heat-insulating component located in the shell, wherein: The open end of the U-shaped heat-conducting metal tube is connected to the shell; The heat absorbing film plate is arranged on the U-shaped heat conducting metal tube; The shielding and reflecting component and the heat absorbing film plate form a cavity, and the U-shaped heat-conducting metal tube body is enclosed in the cavity; The distance between the shielding and reflecting component and the U-shaped heat-conducting metal tube is 0.8-1.5 mm; and / or The distance between the shielding and reflecting component and the heat absorbing film plate is 0.8-1.5 mm; The bracket includes a first bracket and a second bracket used in conjunction with each other, the first bracket is placed between the shell and the heat absorbing film plate, and the second bracket is placed between the shielding and reflecting component and the shell. The first bracket, the second bracket, the heat absorbing film plate and the shielding and reflecting component are all provided with holes and connected to the ceramic heat insulation assembly by bolts; Wherein, the first bracket includes a first bracket crossbeam and two first curved portions extending upward from two ends of the first bracket crossbeam; The second bracket includes a second bracket cross beam and two second curved portions extending upward from two ends of the second bracket cross beam. The first support beam is arranged between the shell and the heat absorbing film plate, the second support beam is arranged between the shielding and reflecting component and the shell, and the two first bent portions and the two second bent portions are both stuck to the inner side of the shell.

2. The heat collector according to claim 1, characterized in that: The open end of the U-shaped heat-conducting metal tube is connected to the shell through a Kovar alloy end head.

3. The heat collector according to claim 1, characterized in that: The shielding reflection component is a groove type, comprising a main body, an extension portion, a first baffle and a second baffle, wherein: The main body is a flat plate, which is placed below the U-shaped heat-conducting metal tube, and a plurality of holes are provided on the flat plate for placing the ceramic heat-insulating assembly; The two ends of the flat plate extend outward to form an extension portion outside the heat absorbing film plate; The first baffle and the second baffle are respectively arranged at two ends of the shielding and reflecting component, and form a groove with the main body and the extending part. Wherein, two notches are arranged on the second baffle plate for the U-shaped heat-conducting metal tube to pass through.

4. The heat collector according to claim 3, characterized in that: 1-8 wells are arranged on the plate.

5. The heat collector according to claim 1, characterized in that: The shell includes an integrally formed glass tube and a glass seal head, and the glass seal head is in a constant curvature form.

6. The heat collector according to claim 1, characterized in that: The first support beam and / or the second support beam are / is a hollow structure.

7. The heat collector according to claim 1, characterized in that: The ceramic heat insulation assembly includes two ceramic washers, a ceramic long column and two ceramic short columns, wherein: The ceramic long column is a column with a through hole, and its two ends are respectively against the heat absorbing film plate and the shielding and reflecting component; The two ceramic washers are washers each having a through hole, and are respectively arranged on the first bracket and the second bracket; The two ceramic short columns are step short columns, including a first column and a second column that are integrally formed and both have through holes, the first columns of the two ceramic short columns are respectively placed in the holes of the heat absorbing film plate and the shielding and reflecting component, and the second columns of the two ceramic short columns are respectively arranged between the first bracket and the heat absorbing film plate, and between the shielding and reflecting component and the second bracket; the diameter of the through hole of the first column is smaller than the diameter of the through hole of the second column; The through holes of the two ceramic washers have the same diameter as the through holes of the first cylinders of the two ceramic short cylinders; the through holes of the ceramic long cylinder have the same diameter as the through holes of the second cylinders of the two ceramic short cylinders; The bolts pass through the through holes to connect the first bracket, the heat absorbing film plate, the shielding and reflecting component and the second bracket.

8. The heat collector according to claim 1, characterized in that: The number of the brackets is N, the number of the ceramic thermal insulation components is 2N, and N is 1-5.

9. The heat collector according to claim 1, characterized in that: The shell includes a light-facing surface and a backlight surface; the heat-absorbing film plate is installed between the light-facing surface of the shell and the U-shaped heat-conducting metal tube, and the side of the heat-absorbing film plate facing the light-facing surface of the shell is coated with a selective absorption coating, and the other side of the heat-absorbing film plate is tightly fitted with the U-shaped heat-conducting metal tube.

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