A type of high-insulation solar vacuum collector with an elliptical cross section

Abstract

This invention discloses a highly insulating solar vacuum collector with a near-elliptical cross-section, belonging to the field of solar collector technology. It includes a transparent shell, a heat-absorbing core, a porous vacuum insulation body, and an outer frame. The transparent shell is composed of multiple sealed cavities with near-elliptical cross-sections, effectively enhancing structural stability and resistance to deformation. The porous vacuum insulation body is composed of glass fiber and vapor-phase SiO2 composite, and integrates a reflective aluminum film, embedded in an elliptical groove at the bottom of the shell, achieving highly efficient heat insulation at a vacuum level of 10 Pa. The heat-absorbing core is installed inside the shell via sheet-like spring clips, without direct contact with the shell, and each heat-absorbing core is connected in series via U-shaped grooves for fluid conduits. The outer frame is connected to the shell via a sliding groove structure, facilitating installation and maintenance. This invention, through comprehensive improvements in structure and materials, reduces heat loss and vacuum technology costs, improves heat collection efficiency and structural reliability, and is particularly suitable for large-size solar thermal systems.

Description

Technical Field

[0001] This invention relates to the field of solar collector technology, and in particular to a highly insulating solar vacuum collector with a near-elliptical cross-section. Background Technology

[0002] Solar thermal utilization is one of the key technologies for achieving energy sustainability and reducing carbon emissions; solar flat plate collectors are representative devices for solar thermal utilization, which absorb solar radiation energy and transfer heat to the working medium.

[0003] Although flat-plate solar collector technology is quite mature, existing designs still have technical bottlenecks and room for optimization, which restricts the further improvement of their heat collection efficiency and the expansion of their application scope.

[0004] The air gap between the heat absorber and the transparent cover not only increases heat conduction but also generates natural convection due to the temperature difference, carrying away heat. Existing designs address this issue by creating a vacuum, but this requires reducing the vacuum level to 10. -3 Only with Pa can effective heat insulation be achieved.

[0005] Large-size solar collectors can significantly reduce the number of collector units in a collector array, effectively reducing the average heat loss per unit light-collecting area. However, large-size vacuum collectors require transparent panels with better mechanical properties; simply increasing the number of supports will lead to increased heat conduction losses.

[0006] Therefore, there is an urgent need for a new type of solar collector that combines excellent thermal insulation performance and structural strength, can achieve efficient heat collection under large-size conditions, and can extend the vacuum maintenance time and reduce the impact of thermal bridge effect to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a high-insulation solar vacuum collector with a near-elliptical cross-section, which overcomes the defects of existing technology, has excellent mechanical properties, provides a structural basis for large-scale production, and has excellent heat insulation capabilities, making full use of the collected thermal energy and achieving higher efficiency.

[0008] To achieve the above objectives, the present invention discloses a highly insulating solar vacuum collector with an elliptical cross-section, comprising a transparent shell, a heat-absorbing core, a porous vacuum insulation body, and an outer frame.

[0009] The transparent shell consists of several closed, independent cavities with an elliptical cross-section and U-shaped grooves between adjacent cavities.

[0010] The heat-absorbing plate core is set inside the cavity, and the number of cores is equal to that of the cavity. The heat-absorbing plate core is equipped with fluid pipes for the flow of heat transfer fluid.

[0011] A porous vacuum insulation material is installed at the bottom layer of the cavity.

[0012] The outer frame is set outside the transparent shell.

[0013] Preferably, the cavity is formed by fusing a glass shell, a front glass cover, and a rear glass cover. The cross-section of the glass shell, the shape of the front glass cover, and the shape of the rear glass cover are all approximately elliptical to enhance the load-bearing capacity and deformation resistance of the collector body.

[0014] Preferably, the cavity is provided with three chambers.

[0015] Preferably, the front glass cover has inlet / outlet holes and a vacuum hole communicating with the cavity; a metal bellows end seal is embedded in the inlet / outlet hole respectively; one end of the bellows end seal is sealed and fixed to the front glass cover, and the other end is connected to the fluid pipe of the heat absorber core. The bellows end seal includes an outlet bellows end seal and an inlet bellows end seal. The bellows end seal utilizes its own tortuous and long thermal path structure to form a high thermal resistance, which can effectively reduce the heat transfer from the high temperature fluid inside to the lower temperature front glass cover, thereby reducing the heat loss at the connection.

[0016] Preferably, the liquid inlet and outlet holes are respectively located on the front glass cover plates of the two end cavities, and the vacuum hole is located on the front glass cover plate of the middle cavity.

[0017] Preferably, both ends of the heat-absorbing plate core are fixedly installed on the transparent shell by elastic fasteners, and the upper surface of the heat-absorbing plate core is provided with a heat-absorbing coating with high temperature resistance and high absorption rate.

[0018] Preferably, the elastic fastener is a sheet-shaped retaining spring. The sheet-shaped retaining spring ensures that there is no direct contact between the heat-absorbing plate core and the glass shell. Furthermore, the sheet-shaped retaining spring has a large heat transfer path, a thin thickness, and high thermal resistance, forming a high thermal resistance thermal path, thereby effectively reducing heat conduction loss.

[0019] Preferably, the fluid pipes in adjacent cavities are interconnected through U-shaped grooves, allowing the heat transfer fluid to flow sequentially through the heat-absorbing plate cores in all cavities and be sealed by brazing. The heat transfer medium flows sequentially through the fluid pipes in multiple cavities, forming a series heat absorption path. During the flow, the heat transfer medium exchanges heat with the solar-heated heat-absorbing plate cores in each cavity, forming a heat exchange flow path of inlet corrugated pipe end-fluid pipe-outlet corrugated pipe end. Therefore, the series heat absorption path extends the heat absorption process of the working medium, allowing it to be fully and uniformly heated to a high temperature before being output.

[0020] Preferably, the outer frame and the transparent shell are slidably connected by a sliding groove structure. The sliding groove structure includes a glass protrusion and a shaped groove adapted to the glass protrusion. The glass protrusion is disposed on the side wall of the transparent shell, and the shaped groove is disposed on the inner wall of the outer frame. The glass protrusion is slidably embedded in the shaped groove.

[0021] Preferably, the ends of the outer frame are also provided with corner brackets for axial positioning and fixing of the transparent shell. The corner brackets abut against the side wall of the transparent shell to prevent it from moving inside the outer frame.

[0022] Preferably, the bottom surface of the porous vacuum insulation body fits into the bottom surface of the glass shell, and the upper surface is provided with a reflective aluminum film to further increase the radiation barrier and reduce the heat radiation loss of the flat plate.

[0023] Preferably, the porous vacuum insulation body is composed of glass fiber and fumed silica, which has extremely low thermal conductivity and increases the mean free path of gas molecules inside the cavity, preventing gas heat conduction and heat convection, and can achieve effective heat insulation at a vacuum level of 10 Pa; the vacuum insulation layer is installed in a preset elliptical groove on the lower surface of each cavity of the glass shell.

[0024] Preferably, the upper surface of the porous vacuum insulation body is provided with a clearance groove, the position of which corresponds to the position of the fluid pipe, to accommodate the fluid pipe and avoid direct contact with the fluid pipe.

[0025] Therefore, the present invention employs the aforementioned highly adiabatic solar vacuum collector with a near-elliptical cross-section, and its specific beneficial effects are as follows:

[0026] This invention, by employing a near-elliptical glass shell cross-section design, fully utilizes the mechanical advantages of curved structures, greatly enhancing the load-bearing capacity and deformation resistance of the collector body. This improvement effectively overcomes the technical difficulties of bending, deformation, and even cracking caused by stress in traditional vacuum collectors, providing a reliable structural foundation for the large-scale and modular design of collectors. By using a porous vacuum insulation material integrated from glass fiber, vapor-phase SiO2, and reflective aluminum film, and precisely embedding it into the elliptical groove on the lower surface of the shell, a highly efficient heat insulation barrier is constructed, providing high heat insulation performance for 10 Pa vacuum conditions, thereby significantly improving heat collection efficiency, especially in cold seasons or under conditions with large temperature differences. The design of connecting the outer frame and the transparent shell through a glass protrusion structure makes on-site installation, subsequent replacement, or maintenance extremely simple, saving time and effort, and significantly reducing the maintenance cost throughout the entire life cycle.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the highly adiabatic solar vacuum collector with a near-elliptical cross-section as described in Embodiment 1;

[0029] Figure 2 This is a schematic diagram of the transparent shell portion of the highly adiabatic solar vacuum collector with a near-elliptical cross-section as described in Embodiment 1.

[0030] Figure 3 This is a partial cross-sectional view of the porous vacuum insulation structure, which is a schematic diagram of the highly insulating solar vacuum collector with an elliptical cross-section as described in Embodiment 1.

[0031] Figure 4 This is a partial cross-sectional view of the highly adiabatic solar vacuum collector with an elliptical cross section as described in Embodiment 2;

[0032] Figure 5 This is a partial cross-sectional view of the high thermal insulation solar vacuum collector with an elliptical cross section described in Embodiment 2, showing the removal of the sheet-like retaining spring support;

[0033] Figure label:

[0034] 1. Transparent shell; 11. Glass shell; 111. U-shaped groove; 112. Glass protrusion; 12. Front glass cover; 121. Vacuum hole; 122. Inlet bellows end seal; 123. Outlet bellows end seal; 13. Rear glass cover; 2. Heat-absorbing plate core; 21. Fluid pipe; 3. Outer frame; 31. Irregular groove; 4. Corner bracket; 5. Porous vacuum insulation body; 51. Reflective aluminum film; 52. Clearance groove; 6. Sheet spring. Detailed Implementation

[0035] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] The present invention will be further described below through specific embodiments. However, it should be understood that these embodiments are only for more detailed description and should not be construed as limiting the present invention in any way, that is, not intended to limit the scope of protection of the present invention.

[0037] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0038] Example 1

[0039] like Figures 1 to 3 As shown, this embodiment provides a large-size solar vacuum collector with an elliptical cross-section, including a transparent shell 1, a heat-absorbing plate core 2, an outer frame 3, a corner bracket 4, a porous vacuum insulation body 5, and a sheet-like retaining spring 6.

[0040] The transparent shell 1 is internally divided into three cavities, which are formed by fusing a glass shell 11, a front glass cover 12, and a rear glass cover 13. The cross-section of the glass shell 11 and the shapes of the front and rear glass cover 13 are all approximately elliptical. A porous vacuum insulation body 5 is precisely filled into an elliptical groove on the lower surface of the transparent shell 1, and a reflective aluminum film 51 is provided on its upper surface. The porous vacuum insulation body 5 is composed of glass fiber and fumed silica.

[0041] Three heat-absorbing core plates 2 are fixed to the three cavities of the transparent shell 1 by multiple leaf springs 6. Fluid pipes 21 on the heat-absorbing core plates 2 between adjacent cavities are brazed together by U-shaped grooves 111 formed on the cavity partitions. The inlet and outlet of the fluid pipes 21 on the heat-absorbing core plates 2 are fixed to the inlet bellows end seal 122 and the outlet bellows end seal 123, respectively. The upper surface of the heat-absorbing core plates 2 is coated with a heat-absorbing coating. The fluid pipes 21 are placed in the clearance groove 52. After installation, the transparent shell 1 is evacuated through the vacuum hole 121 on the front glass cover plate 12, and the vacuum hole 121 is sealed after evacuation to form a sealed space. The transparent shell 1 slides into the irregular groove 31 on the outer frame 3 through the glass protrusion 112, and is axially positioned and fixed at the four corners of the outer frame 3 by the corner brackets 4.

[0042] The specific heat collection and operation process is as follows:

[0043] Shortwave solar radiation passes through the highly transparent shell 1 and irradiates the heat-collecting plate inside the cavity. The heat-absorbing coating on the upper surface of the heat-collecting plate absorbs solar radiation energy and converts it into heat energy, causing the temperature of the heat-collecting plate to rise rapidly. The heat transfer medium is propelled by a circulating pump and enters the cavity of the transparent shell 1 through the fluid pipe 21 connected to the inlet corrugated pipe. It flows through the three cavities in sequence. As the medium flows through the heated pipe, it undergoes efficient heat exchange with the high-temperature heat-absorbing plate core 2, raising its temperature. This series flow channel design greatly extends the heat absorption path and time of the medium, ensuring that it is heated to its maximum temperature fully and uniformly. Finally, the fully heated high-temperature medium flows out from the fluid pipe 21 connected to the outlet corrugated pipe and is transported to the heat exchanger or hot water storage tank through external pipelines, thus providing the user with the required heat.

[0044] Throughout the heat collection and operation process, the multiple insulation design of this invention continues to function, minimizing heat loss.

[0045] In this invention, the sealed cavity inside the transparent shell 1 is evacuated to a high vacuum, virtually eliminating internal air convection heat transfer and gas conduction heat transfer. The porous vacuum insulation body 5 increases the mean free path of gas molecules inside the cavity, enabling efficient heat insulation even at Pascal-level vacuum, reducing evacuation costs, and increasing radiation barriers to reduce heat radiation loss from the flat plate. The heat-absorbing plate core 2 is non-contactly installed with the glass shell 11 via a leaf spring 6, cutting off the metal heat conduction path. Crucially, the bellows end seal connecting the internal and external fluids utilizes its long thermal path and high thermal resistance to significantly reduce heat conduction of the high-temperature working fluid to the lower-temperature front glass cover 12 through the metal connector.

[0046] The heat collection efficiency of the large-size solar vacuum collector with an elliptical cross section provided in this embodiment is compared with that of a traditional flat-plate solar collector. The traditional flat-plate solar collector adopts a gas sandwich structure with a sandwich thickness of about 10 mm and an air thermal conductivity of about 0.02 W / (m·K). The heat collection temperature under standard conditions is about 80°C. This embodiment adopts a high vacuum structure, which basically completely blocks heat conduction and only heat radiation exists. Under standard conditions, the heat collection temperature can reach more than 270°C.

[0047] Example 2

[0048] The structural principle of this embodiment is basically the same as that of Embodiment 1, such as... Figure 4-5 As shown, the difference lies in that the porous vacuum insulation body 5 does not integrate a reflective aluminum film 51 on its surface. The heat-absorbing core 2 is directly arranged in the clearance groove 52 of the porous vacuum insulation body 5 and is directly supported by the porous vacuum insulation body 5 within the transparent shell 1. Although the heat-absorbing core 2 is in direct contact with the porous vacuum insulation body 5 in this embodiment, the porous vacuum insulation body 5 has extremely low thermal conductivity and still has good heat insulation capabilities. Its thermal conductivity is <0.004W / (m·K), which is one order of magnitude lower than the thermal conductivity of air. This significantly improves the heat collection performance and simplifies the structure, making the installation process simpler.

[0049] Example 3

[0050] The structural principle of this embodiment is basically the same as that of Embodiment 1. The main difference is that the connection process for the glass shell 11 to form a sealed space with the front glass cover plate 12 and the rear glass cover plate 13 is not limited to high-temperature welding. Other feasible sealing processes include, but are not limited to: bonding (using high-airtightness adhesives), laser welding (achieving precision welding through local heating), and welding after metallization (first preparing a metallization layer on the glass surface, and then encapsulating it by brazing or sintering).

[0051] Therefore, the present invention adopts the above-mentioned high thermal insulation solar vacuum collector with an elliptical cross section. Through comprehensive improvements in structure and materials, heat loss and vacuum technology costs are reduced, while heat collection efficiency and structural reliability are improved. It is particularly suitable for large-size solar thermal systems.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A highly insulating solar vacuum collector with a near-elliptical cross-section, characterized in that, Includes a transparent shell, a heat-absorbing core, a porous vacuum insulation body, and an outer frame; The transparent shell consists of several closed, independent cavities with an elliptical cross-section and U-shaped grooves between adjacent cavities. The heat-absorbing plate core is set inside the cavity, and the number of cores is equal to that of the cavity. The heat-absorbing plate core is equipped with fluid pipes for the flow of heat transfer fluid. A porous vacuum insulation material is installed at the bottom layer of the cavity. The outer frame is set outside the transparent shell; The fluid pipes in adjacent cavities are interconnected through U-shaped grooves and sealed by brazing. The heat transfer medium flows through the fluid pipes in multiple cavities in sequence, forming a series heat absorption path. During the flow process, the heat transfer medium exchanges heat with the solar-heated absorber core in each cavity; A heat exchange flow path is formed, consisting of an inlet bellows end cap, a fluid pipe, and an outlet bellows end cap. The porous vacuum insulation is composed of glass fiber and fumed silica.

2. The high thermal insulation solar vacuum collector with a near-elliptical cross-section according to claim 1, characterized in that, The cavity is formed by fusing a glass shell, a front glass cover, and a rear glass cover. The cross-section of the glass shell and the shapes of the front and rear glass covers are all approximately elliptical.

3. The highly adiabatic solar vacuum collector with a near-elliptical cross-section according to claim 2, characterized in that, The front glass cover has inlet / outlet holes and a vacuum hole that communicate with the cavity; metal bellows end seals are embedded in the inlet / outlet holes respectively; one end of the bellows end seal is sealed and fixed to the front glass cover, and the other end is connected to the fluid pipe of the heat absorption plate core. The bellows end seal includes an outlet bellows end seal and an inlet bellows end seal.

4. The high thermal insulation solar vacuum collector with a near-elliptical cross-section according to claim 1, characterized in that, The two ends of the heat-absorbing plate core are fixedly installed on the transparent shell by elastic fasteners, and the upper surface of the heat-absorbing plate core is provided with a heat-absorbing coating.

5. A highly adiabatic solar vacuum collector with a near-elliptical cross-section according to claim 1, characterized in that, The outer frame and the transparent shell are slidably connected by a sliding groove structure. The sliding groove structure includes a glass protrusion and a shaped groove that matches the glass protrusion. The glass protrusion is located on the side wall of the transparent shell, and the shaped groove is located on the inner wall of the outer frame.

6. A highly adiabatic solar vacuum collector with a near-elliptical cross-section according to claim 1, characterized in that, The ends of the outer frame are also provided with corner brackets for axial positioning and fixing of the transparent shell, and the corner brackets abut against the side wall of the transparent shell.

7. A highly adiabatic solar vacuum collector with a near-elliptical cross-section according to claim 1, characterized in that, The bottom surface of the porous vacuum insulation body fits into the bottom surface of the glass shell, and the upper surface is provided with a reflective aluminum film.

8. A highly adiabatic solar vacuum collector with a near-elliptical cross-section according to claim 1, characterized in that, The upper surface of the porous vacuum insulation body is provided with a clearance groove, the position of which corresponds to the position of the fluid pipe and is used to accommodate the fluid pipe.

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