Flat-plate solar air collector based on L-shaped double-layer micro heat pipe array-double-layer glass cover plate

Abstract

The application relates to the field of solar light and heat utilization, and discloses a flat-plate type solar air collector based on an L-shaped double-layer micro heat pipe array-double-layer glass cover plate, which comprises a double-layer glass cover plate, a selective absorption coating, an L-shaped micro heat pipe array, flat fins and a heat exchange air duct assembly. During the heat collecting process of the device, sunlight transmits through the double-layer glass cover plate, heats the air layer on the lower side of the cover plate, and transmits heat to the surface of the selective absorption coating through thermal radiation and thermal convection, so as to heat the evaporation section of the micro heat pipe array. The micro heat pipe array heats the low-temperature air in the air duct through the excellent performance of the micro heat pipe array. The excellent heat conduction performance of the L-shaped micro heat pipe array increases the effective heat collecting area of the collector, effectively separates the heat collecting section and the heat collecting section, increases the flow of the gas-liquid phase change working medium in the heat pipe, effectively increases the condensing section area, and improves the heat collecting efficiency of the heat collecting device of the collector.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the field of solar heat collection technology and heat transfer enhancement technology, and builds a flat-plate type solar air collector device based on L-shaped double-layer micro heat pipe array-double-layer glass cover plate, with air as the heat transfer medium. BACKGROUND

[0002] China is rich in solar energy resources, which are widely distributed, clean, environmentally friendly, and economically safe. This provides a guarantee and convenience for solar energy utilization technology. The present study mainly focuses on the photothermal utilization technology of solar energy. The collector is a key component in photothermal technology, which absorbs solar radiation and then transfers the generated heat to the heat transfer medium. The generated heat is used for heating or domestic water and other fields. According to the heat transfer medium of the collector, it can be divided into liquid collectors and air collectors. Compared with liquid collectors, air collectors can directly heat outdoor air to produce hot air, and there is no problem of freezing in winter. A small amount of leakage will not have a significant impact on the overall device performance. The system has low pressure and low price, which can be easily used for winter building heating, industrial and agricultural heating and drying occasions. However, the simple structure of the air collector often has low thermal efficiency. While the air collector with high thermal efficiency often has a complex structure, large flow resistance, and high operating cost. Therefore, from the source, it is necessary to solve the problem of air collector, improve the collection efficiency, reduce heat loss, and reduce flow resistance and cost, which are the key technical problems that need to be solved at present.

[0003] For rural areas in northern China, due to remote location, scattered residence, underdeveloped economy, uneven energy distribution, and other problems, fire and stove are the preferred equipment for northern rural families, which means that coal, straw and other low-cost fuels have become necessary reserves for heating. This is not only not conducive to the development of the ecological environment, but also directly leads to less use of clean energy and difficulty in popularization. Therefore, solar heat collection is a practical and feasible method to solve the problem of rural heating. SUMMARY

[0004] The purpose of the present application is to design a flat-plate type solar air collector device based on L-shaped double-layer micro heat pipe array-double-layer glass cover plate. The L-shaped double-layer micro heat pipe array assembly is used as the core heat transfer element. On the one hand, the double-layer glass can effectively reduce heat loss, and on the other hand, the use of L-shaped double-layer micro heat pipe array technology can increase the heat exchange area of the condensation section, effectively remove the heat absorbed by the evaporation section, and thus improve the overall heat collection efficiency of the heat collection device. Compared with the traditional circular heat pipe, the micro heat pipe array is flat, has a larger specific surface area, can be more easily attached to the selective heat absorption film, and reduces the contact thermal resistance. At the same time, the micro heat pipe array technology has better thermal conductivity than silver, copper, aluminum, etc., better temperature uniformity, high equivalent thermal conductivity, simple structure, and is suitable for long-distance heat transfer, etc., so it is very suitable for being introduced into the field of solar heat utilization. The application of micro heat pipe array technology not only optimizes the heat collection plate, increases the effective heat collection area, realizes the effective separation of the heat collection section and the heat removal section, reduces the cost of the overall device of the solar air collector, but also optimizes the air heat exchange flow channel, greatly reducing the flow resistance.

[0005] The technical scheme of the present application is as follows:

[0006] A flat-plate type solar air collector device based on L-shaped double-layer micro heat pipe array-double-layer glass cover plate, characterized by a flat-plate type solar air collector device based on L-shaped double-layer micro heat pipe array-double-layer glass cover plate, the main components include: air duct (1), double-layer glass cover plate (2), selective absorption coating (3), L-shaped double-layer micro heat pipe array assembly (4), box interior insulation cotton (5), heat collection box (6), rectangular flat fin (7).

[0007] The L-shaped double-layer micro heat pipe array assembly (4) is a parallel layering of two layers of L-shaped plate structures, and is divided into three communicating sections along the length direction: a heat collection section, an insulation section and a heat removal section. Each layer corresponds to a bottom cavity flat structure for the heat removal section, a vertical cavity flat structure for the heat collection section, and an insulation section connecting the heat collection section and the heat removal section, wherein the insulation section and the heat removal section are the same bottom cavity flat structure. A plurality of L-shaped plate structures are arranged in parallel along the width direction.

[0008] The L-shaped double-layer micro heat pipe array assembly (4) is connected by face-to-face bonding between the upper and lower layers of the flat micro heat pipe array through the bottom flat joint, and the working medium in the upper and lower layers of the micro heat pipe array is not communicated. The upper and lower layers of the micro heat pipe are glued with heat-conducting silicone (8), and the excess heat-conducting silicone (8) is squeezed out while the two layers of L-shaped micro heat pipes are tightly attached and fixed and compacted by means of flanges and gaskets, bolts and nuts.

[0009] The upper surface of the heat collecting section of the L-shaped double-layer micro heat pipe array assembly (4) is pasted with a selective absorption coating (3); the upper surface of the selective absorption coating (3) is a double-layer glass cover plate (2); the lower surface of the bottom of the L-shaped double-layer micro heat pipe array assembly (4) is thermal insulation cotton (5); the lower surface of the thermal insulation cotton (5) is a heat collecting box body (6), the heat collecting section of the L-shaped double-layer micro heat pipe array assembly (4) is completely placed in the inner cavity of the heat collecting box body (6), and the heat collecting box body (6) and the double-layer glass cover plate (2) are combined and matched into a closed structure.

[0010] The heat collecting section of the L-shaped double-layer micro heat pipe array assembly (4) is placed in an air duct (1); the front surface and the back surface of each layer of the heat collecting section of the double-layer L-shaped double-layer micro heat pipe array assembly (4) are correspondingly pasted or welded with rectangular flat fins (7), low-temperature air is sent into the air duct (1) by a blower to exchange heat to obtain high-temperature air, and the rectangular flat fins (7) increase the heat exchange area and the heat exchange performance.

[0011] The double-layer glass cover plate (2) is filled with air in the glass interlayer.

[0012] The rectangular flat fin (7) is a component with large heat exchange area, large expansion coefficient, compact structure and low cost.

[0013] The heat collecting box body (6) and the air duct (1) are both subjected to thermal insulation treatment with thermal insulation materials.

[0014] The heat collecting box body (6) should be provided with a line slot hole corresponding to the glass cover plate and a sealing buckle in advance during processing, and the surrounding of the heat collecting box body and the connection between the heat collecting box body and the glass cover plate are sealed by using glass glue, AB glue and a sealing rubber ring during installation;

[0015] The selective absorption coating (3) adopts a selective heat absorption blue film with high absorption rate and low emission rate.

[0016] The L-shaped flat plate is an aluminum alloy metal plate with a thickness of 3 mm, which is the appearance of the heat pipe array assembly (4), and is internally provided with a plurality of non-communicating micro heat pipe channels with micro fins, the equivalent diameter of each micro heat pipe channel is 5 mm, a micro groove structure is formed between adjacent micro fins, and each independent micro heat pipe channel is subjected to vacuumization and filling treatment of a working medium, and the working medium filled in the micro heat pipe channel is selected from acetone, methanol, ethanol, R134a and other refrigerants.

[0017] The flat plate type solar air heat collector device based on the double-layer glass of the L-shaped double-layer micro heat pipe array absorbs solar energy during a sunny day without clouds, converts the absorbed solar radiation into heat energy, and is used in the fields of building heating and domestic water, and is placed southward according to the local latitude plus or minus 10°;

[0018] The double-layer glass cover plate (2) is made of super-white light-transmitting tempered glass with explosion-proof, high transmittance, small heat loss and thickness of 3 mm, and the air layer with thickness of 12 mm is filled between the double-layer glass to keep warm.

[0019] Technical effects of the present application:

[0020] The high efficient heat transfer performance of the micro heat pipe array assembly (4), the high efficient heat absorption characteristics of the selective absorption coating (3) and the reinforced heat exchange element of the rectangular flat fin (7) are selected to realize the effective heat exchange of the low-temperature air at the air duct inlet, and then the effective heat utilization of solar energy is realized.

[0021] The micro heat pipe array with the micro heat pipe array as the core heat exchange element is selected as the flat-plate type solar air collector in the present application. According to the heat balance principle, the length of the condensation section matched with the heat collection area of the evaporation section is determined, and compared with the conventional flat-plate type micro heat pipe array, the flat micro heat pipe array is bent during processing, and then an L-shaped flat micro heat pipe array (4) is made. Two L-shaped micro heat pipes with different sizes are placed above and below, and are glued by using heat-conducting silicone. The whole device is integrated, which not only effectively increases the flow of the phase change of the gas-liquid working medium in the heat pipe array, but also greatly increases the effective heat exchange area of the condensation section. At the same time, the double-layer glass cover plate (air-filled interlayer) is selected in the collector device, which increases the heat preservation performance of the whole collector and reduces the heat loss of the glass cover plate to the outside environment. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural exploded schematic view of the present application;

[0023] Figure 2 is a manufacturing method exploded view of the L-shaped double-layer micro heat pipe array assembly adopted by the present application;

[0024] Figure 3 is a three-dimensional structure schematic view of the L-shaped micro heat pipe array unit and device with rectangular flat fins;

[0025] Figure 4 is a schematic view of the internal section at the cross section of the L-shaped double-layer micro heat pipe array assembly;

[0026] Air duct 1, double-layer glass cover plate 2, selective absorption coating 3, L-shaped double-layer micro heat pipe array assembly 4, internal heat preservation cotton of box 5, heat collection box 6, rectangular flat fin 7, heat-conducting silicone 8, gasket 9, bolt and nut 10, micro channel 11, micro fin 12. DETAILED DESCRIPTION

[0027] The present application will be described in detail in combination with the description of the drawings. However, the present application is not limited to the following

[0028] EMBODIMENT

[0029] Example 1

[0030] Figure 1 The structure of the flat-plate solar air collector based on the L-shaped double-layer micro heat pipe array-double-layer glass cover plate in the present application is schematically shown in the exploded view. The main components include air duct 1, double-layer glass cover plate 2, selective absorption coating 3, L-shaped double-layer micro heat pipe array assembly 4, internal insulation cotton 5, heat collection box 6, and rectangular flat fin 7. During a sunny day, the collector device is exposed to sunlight. The sunlight passes through the double-layer glass cover plate 2, is absorbed by the selective absorption coating 3, and is converted into heat energy. The heat energy is then exchanged with the evaporation section of the L-shaped double-layer micro heat pipe array assembly 4. The evaporation section of the L-shaped double-layer micro heat pipe array assembly 4 relies on the phase change of the working medium in the heat pipe to release the heat at the condensation section.

[0031] Figure 2 The production method of the L-shaped double-layer micro heat pipe array assembly used in the present application is schematically shown in the exploded view. In the present case, the two layers of L-shaped flat micro heat pipe array are filled with thermally conductive silicone 8, and are fixed by gaskets 9 and bolts and nuts 10. After the silicone is cured, the gaskets 9 and the bolts and nuts 10 are removed to complete the production of the double-layer L-shaped micro heat pipe array unit. The collector in the present case contains 11 groups of L-shaped double-layer micro heat pipe array units, and the production method is consistent.

[0032] Figure 3 The three-dimensional structure of the L-shaped micro heat pipe array unit and device with rectangular flat fins is schematically shown in the view. The selective absorption coating 3 is pasted on the surface of the L-shaped double-layer micro heat pipe array assembly 4 using thermally conductive silicone 8. The rectangular flat fins 7 are attached to the surface of the condensation section of the L-shaped double-layer micro heat pipe array assembly 4 by gluing or welding. The three-dimensional structure of the device indicates that during the day, the collector releases the energy collected from sunlight into the air duct 1, exchanges heat with the air flowing in the air duct 1, and sends the hot air to the user end in need.

[0033] Figure 4 The internal section of the L-shaped double-layer micro heat pipe array assembly is schematically shown in the view. The micro heat pipe array is made of metal material by welding, stamping, or extrusion molding. On the basis of the conventional micro heat pipe array, the condensation section is bent to form an L-shaped micro heat pipe array. The micro heat pipe contains independent and parallel two or more micro channels 11. The equivalent diameter of each micro channel 11 is about 5 mm. The inner wall of each micro channel 11 is provided with micro fins 12. The phase change working medium is filled by vacuum extraction. The working medium is generally a refrigerant such as acetone, methanol, ethanol, R134a, etc. In addition, the micro channels 11 are connected to each other through the pipe wall, which fully improves the reliability of the micro heat pipe array.

[0034] The working medium in the double-layer L-shaped micro heat pipe array is not communicated with each other.

[0035] The air duct 1, the heat collecting box 6 and the outer surface of the heat insulation section of the device are provided with heat preservation materials, and the detailed thickness is determined according to the price and the heat collecting performance of the heat collector.

[0036] When the heat collecting device is used for heat collecting, it is suitable to be placed southward according to the local latitude plus or minus 10°.

[0037] In the heat collecting process of the device, the sunlight transmits through the double-layer glass cover plate, heats the air layer under the cover plate, the sunlight through the glass transmits heat to the surface of the selective absorption coating by means of heat radiation and heat convection, and then heats the evaporation section of the micro heat pipe array, the micro heat pipe array heats the low-temperature air in the air duct by its excellent performance. The solar flat plate heat collector device increases the effective heat collecting area of the heat collector by using the excellent heat conduction performance of the L-shaped micro heat pipe array, realizes the effective separation of the heat collecting section and the heat collecting section, increases the flow of the gas-liquid phase change working medium in the heat pipe, effectively increases the area of the condensing section, improves the heat collecting efficiency of the heat collector heat collecting device, and is applied to the winter heating in the northern rural areas, promotes the development and use of renewable energy, and is a practical and clean heating method.

Claims

1. A flat-plate type solar air collector based on L-shaped double-layer micro heat pipe array-double-layer glass cover plate, characterized in that, The main components include: air duct (1), double-layer glass cover plate (2), selective absorption coating (3), L-shaped double-layer micro heat pipe array assembly (4), heat preservation cotton inside the box (5), heat collecting box (6), rectangular flat fin (7); The L-shaped double-layer micro heat pipe array assembly (4) is a parallel layering of two layers of L-shaped plate structures, and is divided into three communicating sections along the length direction: a heat collecting section, an insulation section and a heat taking section; the corresponding heat taking section of each layer is a bottom cavity flat plate structure, the heat collecting section is a vertical cavity flat plate structure, the insulation section connects the heat collecting section and the heat taking section, and the insulation section and the heat taking section are the same bottom cavity flat plate structure; a plurality of L-shaped plate structures are arranged in parallel along the width direction; The L-shaped double-layer micro heat pipe array assembly (4) is connected by a face-to-face bonding connection mode of the bottom flat type between the upper and lower layers of the flat micro heat pipe array, and the working medium in the upper and lower layers of the micro heat pipe array is not communicated; the upper and lower layers of the micro heat pipe are glued by using heat-conducting silicone (8), and the heat-conducting silicone (8) is squeezed out during gluing by means of flanges and gaskets, bolts and nuts for fixing and compacting, so as to ensure that the two layers of L-shaped micro heat pipes are tightly attached while the excess heat-conducting silicone (8) is squeezed out; The upper surface of the heat collecting section of the L-shaped double-layer micro heat pipe array assembly (4) is pasted with the selective absorption coating (3); the upper surface of the selective absorption coating (3) is the double-layer glass cover plate (2); the lower surface of the bottom of the L-shaped double-layer micro heat pipe array assembly (4) is the heat preservation cotton (5); the heat collecting box (6) is below the heat preservation cotton (5), and the heat collecting section of the L-shaped double-layer micro heat pipe array assembly (4) is completely placed in the inner cavity of the heat collecting box (6); the heat collecting box (6) and the double-layer glass cover plate (2) are combined and matched to form a closed structure; The heat taking section of the L-shaped double-layer micro heat pipe array assembly (4) is placed in the air duct (1); the front and back surfaces of each layer of the heat taking section of the double-layer L-shaped double-layer micro heat pipe array assembly (4) are correspondingly pasted or welded with the rectangular flat fin (7), low-temperature air is sent into the air duct (1) by a blower to exchange heat to obtain high-temperature air, and the rectangular flat fin (7) increases the heat exchange area and heat exchange performance.

2. A flat plate solar air collector based on L-shaped two-layer micro heat pipe array-two layer glass cover plate according to claim 1, characterized in that, The double-layer glass cover plate (2) is filled with air between the glass layers.

3. A flat plate solar air collector based on L-shaped two-layer micro heat pipe array-two layer glass cover plate according to claim 1, characterized in that, The rectangular flat fin (7) is a component with large heat exchange area, large expansion coefficient, compact structure and low cost.

4. The flat plate solar air collector based on L-shaped two-layer micro heat pipe array-two layer glass cover plate according to claim 1, characterized in that, The heat collecting box (6) and the air duct (1) are both subjected to heat preservation and insulation treatment by using heat preservation materials.

5. The flat plate solar air collector based on L-shaped two-layer micro heat pipe array-two layer glass cover plate according to claim 1, characterized in that The heat collecting box (6) should be pre-processed to reserve corresponding linear slot hole positions and sealing buckles with the glass cover plate, and the surrounding of the heat collecting box and the connection between the heat collecting box and the glass cover plate are sealed by using glass glue, AB glue and sealing rubber rings during installation.

6. A flat plate solar air collector based on L-shaped two-layer micro heat pipe array-two layer glass cover plate according to claim 1, characterized in that, The selective absorption coating (3) uses a selective heat absorption blue film with high absorption rate and low emission rate.

7. A flat plate solar air collector based on L-shaped two-layer micro heat pipe array-two layer glass cover plate according to claim 1, characterized in that, The L-shaped double-layer micro heat pipe array assembly (4) is in the appearance of 3mm thick aluminum alloy metal plate, and the inside is several unconnected micro heat pipe channels with micro fins, the equivalent diameter of each micro heat pipe channel is 5mm, the micro channel structure is formed between adjacent micro fins, and the micro heat pipe channels are vacuumized and filled with working medium.

8. A flat plate solar air collector based on L-shaped two-layer micro heat pipe array-two layer glass cover plate according to claim 1, characterized in that, Absorbing solar energy in sunny and cloudless day, converting the absorbed solar radiation into heat energy, and using the heat energy for building heating and domestic water, and placing according to the local latitude plus or minus 10 degrees south.

9. A flat plate solar air collector based on L-shaped two-layer micro heat pipe array-two layer glass cover plate according to claim 1, characterized in that, The double-layer glass cover plate (2) adopts the super-white light transmission tempered glass with explosion-proof, high transmittance, small heat loss and thickness of 3mm, and the air layer with thickness of 12mm is filled between the double-layer glass for heat preservation.

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