A highly efficient sun-chasing, two-end condensing parabolic solar heat pipe collector

Abstract

The present invention relates to an efficient, two-end condensing parabolic solar heat pipe collector. It comprises a glass cover, a flat heat absorbing plate, multiple heat pipes, a V-shaped reflector, a rotating shaft, a stepper motor, a base, a disk, and an air flow channel. The heat pipes are symmetrically condensed parabolic heat pipes at both ends, with condensation sections at the ends of the parabola and an evaporation section below the parabola's diameter to the vertex. Each heat pipe is equidistantly fixed to the centerline of the base by support keys. The condensation section is surrounded by a flat heat absorbing plate to form an air flow channel. One end of the air flow channel is for cold air inlet, and the other end is for hot air outlet. The heat pipe condensation sections are arranged side by side within the air flow channel. The outer surface of the flat heat absorbing plate is coated with a selective absorption coating. The flat heat absorbing plate is surrounded by a glass cover. A V-shaped reflector is provided on the base. A rotating shaft is mounted below the base and connected to the stepper motor. The present invention integrates the technologies of automatically rotating, two-end condensing parabolic heat pipes to improve the overall light-to-heat conversion efficiency of the collector.

Description

Technical Field

[0001] The invention relates to a solar energy high-efficiency heat pipe collector, in particular to a two-end condensing parabolic solar energy high-efficiency heat pipe collector with a V-shaped reflecting plate and capable of automatically tracking light. Background Art

[0002] The shortage of fossil energy and its pollution to the environment have led to the continuous in-depth development of solar energy as a clean energy. The research and development of efficient photothermal systems has become a research hotspot in recent years. Among them, solar flat-plate collectors, the core components of photothermal conversion, have developed rapidly.

[0003] Traditional flat-plate collectors consist of a glass cover, a heat-absorbing plate, a shell, and insulation materials. They offer excellent pressure-bearing capacity, a high degree of building integration, strong structural capabilities, and a large heat-absorbing area. However, the heat dissipation structure on the flat-plate heat-absorbing plate consists solely of a nano-scale coating, resulting in poor insulation. Heat dissipation is also more rapid at night when there's no sunlight. To maximize the effectiveness of solar collectors during periods of sunlight, the collector's installation angle must be adjusted based on the collector's latitude. The sun rises in the east in the morning and sets in the west at night, and its position fluctuates. Failure to adjust this will negatively impact the collector's heat absorption and utilization. Summary of the Invention

[0004] The purpose of the present invention is to provide an efficient light-chasing type two-end condensing parabolic solar heat pipe collector, which is used to solve the problem that existing solar collectors cannot achieve light tracking, affecting the heat absorption effect.

[0005] The technical solution adopted by the present invention to solve its technical problems is: this high-efficiency light-chasing type two-end condensing parabolic solar heat pipe collector includes a glass cover, a flat heat absorbing plate, multiple heat pipes, a V-shaped reflector, a rotating shaft, a stepping motor, a base, a disc, and an air flow channel. The heat pipe is coated with black nickel material. The heat pipe is a symmetrical condensing parabolic heat pipe at both ends. The two ends of the parabola are condensing sections, and the section below the parabola diameter to the vertex is the evaporation section. There is a vacuum between the inner and outer diameters of the heat pipe, and each heat pipe is fixed to the center line of the base with support keys at equal distances. The condensing section is surrounded by a flat heat absorbing plate to form an air flow channel. One end of the air flow channel is the cold air inlet, and the other end is the hot air outlet. The heat pipe condensing sections are arranged side by side in the air flow channel. The outer surface of the flat heat absorbing plate is provided with a selective absorption coating. The outer side of the flat heat absorbing plate is surrounded by a glass cover plate. The glass cover plate can transmit visible light and block far infrared rays. A V-shaped reflector plate is provided on the base, and a rotating shaft is installed under the base. The rotating shaft is connected to a stepper motor. The stepper motor is installed in the disc, and the disc is a hollow disc.

[0006] In the above scheme, the heat pipe has a focal length of 64mm, a parabola opening width of 250mm, and a parabola equation of y=x 2 / 2 parabolic heat pipe.

[0007] In the above scheme, the V-shaped reflector is placed directly below each heat pipe. The top edge of the V-shaped reflector coincides with the projection of the heat pipe axis onto the base. The two end lines are in the middle of the two heat pipes and perpendicular to the surface of the base. The solar radiation missed by the gaps between the heat pipes is reflected by the V-shaped reflector to the heat pipe and absorbed again, so as to ensure that the direct light that the heat pipe should receive without the reflector is still captured under the V-shaped reflector.

[0008] In the above scheme, the driver of the stepper motor adopts A4988, and its step angle is 90°. According to the solar hour angle, 0° is at noon, and it moves 15° per hour. Before 9 o'clock, the collector faces east. At 9 o'clock, the stepper motor is used to rotate the collector 90° clockwise, and another 90° at 15 o'clock.

[0009] In the above solution, a glass cover plate capable of covering the entire collector is provided above the two air flow channels.

[0010] In the above scheme, the flat heat absorbing plate is coated with a Ta2O5 coating, an A-Si:H coating, a TEMP coating, and a TiO2-A coating. The thickness of the Ta2O5 coating is 150 nm, the thickness of the A-Si:H coating is 78.67 nm, the thickness of the TEMP coating is 10.29 nm, and the thickness of the TiO2-A coating is 31.04 nm. The Ta2O5 coating, the A-Si:H coating, the TEMP coating, and the TiO2-A coating are composited together to form a selective absorption coating.

[0011] In the above scheme, the inner diameter of the heat pipe is 16 cm and the outer diameter is 18 cm; a flat heat absorbing plate is used around the condensing section of the heat pipe to form an air flow channel with a length of 280 cm, a width of 42 cm and a height of 51 cm.

[0012] There are nine heat pipes in the above solution.

[0013] The heat collection method of the above-mentioned efficient sun-chasing type two-end condensing parabolic solar heat pipe collector is as follows:

[0014] Heat is absorbed by a combination of a flat plate heat absorber and a heat pipe. The heat pipe adopts a symmetrical condensing parabolic heat pipe at both ends. The flat plate heat absorber is located outside the condensing section of the heat pipe, and heat is absorbed by the evaporating section of the heat pipe and the flat plate heat absorber together. As the solar hour angle changes, the stepper motor drives the collector to chase the light through the rotating shaft. At sunrise, the collector faces east. At 9 a.m., the collector rotates 90 degrees clockwise. At 3 p.m., the collector rotates 90 degrees clockwise and faces west. Solar radiation is radiated through the glass cover to the evaporating section of the heat pipe and the flat plate heat absorber. The heat exchange medium water in the heat pipe is heated and vaporized and enters the two sets of condensing sections. The flat plate heat absorber absorbs the solar energy radiated to the air flow channel. Cold air enters from the air flow channel and is heated by the condensing section of the heat pipe and the flat plate heat absorber, and the hot air flows out from the hot air outlet. The V-shaped reflector changes the path of solar radiation that leaks between the heat pipes and reflects it to the evaporating section of the heat pipe, heating the heat exchange medium in the heat pipe. The condensing section improves the heat exchange efficiency by turbulence in the air flow channel. Beneficial effects

[0015] 1. The heat pipe collector of this invention places the condensing section within the air flow channel to heat the air. A flat heat absorber serves as the air flow channel wall. This effectively absorbs solar radiation near the condensing section and, together with the heat pipe condensing section, heats the air, improving the collector's solar energy utilization. Compared to traditional straight heat pipes, the new parabolic heat pipe has two condensing sections, increasing the heat exchange area. By leveraging the advantages of its parabolic structure, it can better collect solar radiation.

[0016] 2. This invention utilizes V-shaped reflectors, integrated with automatically rotating light-tracking and two-end condensing parabolic heat pipe technology. This collector achieves uniform heat absorption across the heat pipes at varying times through automatic rotation. The two condensing sections of the parabolic heat pipes increase the heat exchange area with the air, enhancing the heat transfer efficiency of the heat pipes. Flat heat absorbing plates are placed around the air flow path, further heating the air as it exchanges heat with the condensing sections of the heat pipes, thereby improving the overall photothermal conversion efficiency of the collector.

[0017] 3. This invention designs a parabolic heat pipe with symmetrical condensation at both ends. This double-ended condensation provides a larger heat exchange area than traditional single-ended condensation. Furthermore, the parabolic vacuum tube effectively collects solar radiation, accelerating the absorption of heat by the working fluid in the evaporation section, which then vaporizes and releases heat in the condensation section, thereby improving the efficiency of the collector.

[0018] 4. In the present invention, a V-shaped reflector is added under the heat pipe. There is light leakage in the gap between the heat pipes in the collector. The V-shaped reflector reflects the leaked solar radiation to the evaporation section of the heat pipe, thereby improving the heat collection capacity of the collector.

[0019] 5. The present invention uses a driver to control the automatic rotation of the shaft, which can be driven by a stepper motor to the appropriate position at a fixed time. From sunrise to 9:00 AM, the collector faces east, and from 3:00 PM to sunset, the collector faces west. This ensures that solar radiation is absorbed to a high degree throughout the day. Two clockwise rotations of the collector constitute a cycle.

[0020] 6. In the present invention, the air flow channel is surrounded by a flat heat absorbing plate with a Ta2O5 / A-Si:H / TEMP / TiO2-A coating, which can absorb solar radiation projected onto the air flow channel. Together with the condensation section, it heats the air to maximize the air heat absorption as much as possible.

[0021] 7. In the present invention, the nine condensation sections at each end of the heat pipe are inserted into the air flow channel, which changes the air circulation area and can further play the role of turbulence and heat exchange enhancement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a top view of the present invention.

[0023] Figure 2 for Figure 1 Cross-sectional view of section AA.

[0024] Figure 3 It is a side view of the present invention.

[0025] Figure 4 It is the front view of the present invention.

[0026] Figure 5 for Figure 4 Cross-sectional view of section BB.

[0027] Figure 6 It is a perspective view of the present invention.

[0028] Figure 7 Schematic diagram of a parabolic two-end condensing heat pipe.

[0029] In the figure: 1 glass cover; 2 heat pipe; 3 flat heat absorbing plate; 4 cold air inlet; 5 hot air outlet; 6 air flow channel; 7 rotating shaft; 8 stepping motor; 9 base; 10 disk; 11 V-shaped reflector. DETAILED DESCRIPTION

[0030] Combine Figure 1-7As shown, this highly efficient, sun-chasing, double-ended condensing parabolic solar heat pipe collector is a parabolic double-ended condensing heat pipe collector with a V-shaped reflector. It comprises a glass cover 1, heat pipes 2, a flat plate heat absorber 3, an air duct 6, a rotating shaft 7, a stepper motor 8, a base 9, a disk 10, and a V-shaped reflector 11. The glass cover 1 is flat glass, the heat pipes 2 are black nickel-coated double-ended parabolic heat pipes, and the flat plate heat absorber 3 absorbs solar radiation directed toward the air duct. It is fixed around the air duct 6 and inside the glass plate. The flat plate heat absorber 3 is coated with a Ta2O5 / A-Si:H / TEMP / TiO2-A composite coating. The base 9 is a rectangular parallelepiped. There are nine heat pipes 2, each of which is equidistantly fixed to a base 9. The parabolic equation is y = x² / 2, with a focal length of 64 cm and an opening width of 250 cm. The heat pipes have an inner diameter of 16 cm and an outer diameter of 18 cm, and a vacuum state is maintained in the center. Flat-plate heat absorbing plates 3 are used around the condensing section of the heat pipes to form two air flow channels 6, each 280 cm long, 42 cm wide, and 51 cm high. The flat-plate heat absorbing plates 3 are encapsulated on the outside with a glass cover 1, and a glass cover 1 that covers the entire collector is placed above the air flow channels 6. A V-shaped reflector 11 is installed on the base 9. To ensure that reflected radiation reaches the evaporating section of the heat pipes, the top edge of the V-shaped reflector 11 is collinear with the heat pipe axis projected onto the base, with the two end lines located midway between the two heat pipes and perpendicular to the base surface. The height of the V-shaped reflector determines the angle between the two heat pipes. To ensure uniform heating at any time, a rotating shaft 7 is welded under the base 9. Under the rotating shaft 7 is a hollow disc with a stepper motor 8. The stepper motor 8 drives the collector to rotate, evenly absorbing solar radiation and enhancing heat exchange. According to the definition of the solar hour angle, starting from noon as 0°, it moves 15° per hour. Therefore, before 9 o'clock in the morning, the collector faces east, and the rotating shaft automatically rotates 90° clockwise at 9 o'clock, and another 90° clockwise at 3 o'clock in the afternoon.

[0031] The present invention utilizes the highly efficient heat exchange characteristics of phase change, transferring heat from the evaporation section to the condensation section through the phase change and flow of the working medium. Heat pipe 2 absorbs heat in the evaporation section, and the working medium vaporizes to generate steam that flows within the pipe to the condensation section. This heat pipe has two condensation sections, and the double-ended condensation increases the heat exchange area compared to traditional single-ended condensation. The parabolic structure is superior to traditional straight pipes in collecting solar radiation, improving the collector's absorption capacity.

[0032] The two ends of the heat pipe parabola are the condensation section, and the section below the parabola diameter to the vertex is the evaporation section. A vacuum state exists between the inner and outer diameters of the heat pipe, effectively preventing the heat from radiating outward from the evaporation section and the insulation section. Nine parabolic heat pipes are equidistantly fixed to the centerline of the base with support keys. The condensation section is surrounded by a flat heat-absorbing plate with a selective absorption coating, forming two air flow channels, which can further absorb solar radiation and enhance gas heat exchange. To ensure that the energy absorbed by the flat heat-absorbing plate is greater than the energy lost, it is covered with a glass cover that can transmit visible light and block far infrared rays to reduce heat loss.

[0033] The heat pipe uses a parabolic heat pipe with condensation at both ends. Based on the theory of gravity heat management, its evaporation section is set below the parabola diameter. Compared with traditional heat pipes with condensation at one end, it has better heat exchange performance. It can use the advantages of the parabolic structure to collect more solar radiation. At the same time, the heat pipe is coated with black nickel material to improve solar absorption rate.

[0034] Because there will be light leakage between the heat pipes arranged in parallel, the present invention adds a V-shaped reflector 11 under the heat pipe 2. By changing the path of the missed light, it reflects it to the evaporation section of the heat pipe, thereby increasing the light absorption of the collector. The top edge of the reflector and the axis of the heat pipe are projected on the base in a collinear manner, and the two end lines are located in the middle of the two heat pipes and perpendicular to the surface of the base. The angle of the reflector is controlled by the height of the V-shaped reflector. It adopts a one-time die-casting technology, with high strength, easy processing and convenient installation. The reflector is placed directly below each heat pipe (the top edge of the V-shaped reflector coincides with the projection of the axis of the heat pipe to the base). The solar radiation missed by the gaps between the heat pipes is reflected by the reflector to the heat pipe and absorbed again, so as to ensure that the direct light that the vacuum tube should receive without the reflector is still captured under the V-shaped reflector.

[0035] The rotating shaft 7 uses a stepper motor 8 to drive the collector to follow the sun. Although parabolic heat pipes can effectively receive solar radiation, the size of their openings limits the range of sunlight absorbed. The evaporation section of this collector is evenly heated only when the solar hour angle is between -45° and 45°. The automatic rotating shaft uses a stepper motor to rotate the collector 90° clockwise at specified times (9:00 AM and 3:00 PM), ensuring uniform heating at all times and maximizing solar radiation absorption.

[0036] The driver of the stepper motor adopts A4988, and its step angle is 90°. It is calculated based on the solar hour angle with noon as 0°, and moves 15° per hour. Before 9 o'clock, the collector faces east. At 9 o'clock, the stepper motor is used to make the collector rotate 90° clockwise, and another 90° at 15 o'clock.

[0037] The air flow channel of the present invention is surrounded by a flat heat absorbing plate, which is used to absorb the solar energy radiated to the surface of the air flow channel and further utilize this energy. 5 / The A-Si:H / TEMP / TiO2-A coating uses W as a metallic substrate. A-Si:H / TEMP serves as the absorption layer. The advantage of this dual-layer absorption layer is that it not only meets the requirement for high absorptivity but also maintains a low radiant emissivity. While the average visible light absorptivity of TiO2-A does not reach 90%, its high infrared reflectivity allows the absorption layer to absorb infrared radiation generated by the absorption layer, allowing for repeated absorption by the absorption layer, thus increasing the absorption rate of the heat sink. Ta2O5 serves as an anti-reflection layer, offering high transmittance. The Ta2O5, A-Si:H, TEMP, and TiO2-A coatings are combined to form a selective absorption coating. The thicknesses of the Ta2O5, A-Si:H, TEMP, and TiO2-A coatings are 150nm, 78.67nm, 10.29nm, and 31.04nm, respectively. The collector efficiency of the coated heat absorbing plate is 19.6% higher than that of the uncoated heat absorbing plate, which can greatly improve the collector efficiency.

[0038] The present invention drives the rotating shaft 7 through the stepping motor 8 to rotate the heat collector to a certain angle within a specified time, thereby ensuring that the heat collector can evenly absorb solar radiation at any time and improving the thermal efficiency of the heat collector.

[0039] The heat collection method of the present invention:

[0040] The present invention combines a flat-plate heat absorbing plate 3 and a heat pipe 2 to absorb heat. The heat pipe adopts a symmetrical condensing parabolic heat pipe at both ends. The flat-plate heat absorbing plate is located outside the heat pipe condensing section inside the air flow channel, and heat is absorbed by the heat pipe evaporating section and the flat-plate heat absorbing plate together. As the solar hour angle changes, the stepper motor 8 drives the heat collector via the rotating shaft 7 to follow the sun, ensuring that the heat collector is evenly heated at any time. At sunrise, the heat collector faces east. At 9 a.m., the heat collector rotates 90 degrees clockwise. At 3 p.m., the heat collector rotates 90 degrees clockwise and faces west. Solar radiation passes through the glass cover 1 and radiates to the heat pipe evaporating section and the flat-plate heat absorbing plate inside the air flow channel. The heat exchange medium water in the heat pipe 2 is heated and vaporized and enters the two sets of condensing sections. The flat-plate heat absorbing plate 3 absorbs the solar energy radiated to the air flow channel. Cold air enters from the cold air inlet 4 at one end of the air flow channel 6, is heated by the heat pipe condensing section and the heat absorbing plate, and flows out from the hot air outlet 5. The reflector located directly below the heat pipe redirects solar radiation that escapes between the heat pipes, reflecting it toward the evaporation section, thereby heating the heat transfer medium within the heat pipe more quickly. The condensation section enhances heat transfer efficiency by turbulent flow within the air flow channel.

[0041] The present invention has a parabolic heat pipe with symmetrical condensation at both ends. Its parabolic structure can collect solar energy very well. The two condensation sections increase the heat exchange area with the cold air to improve the heat exchange efficiency of the collector. Combining the flat plate collector and the heat pipe collector effectively solves the problem of the heat pipe condensation section not absorbing solar radiation. The advantage of the vacuum environment between the inner and outer walls of the heat pipe is utilized to reduce the heat dissipation of the water in the evaporation section after being heated, reduce heat loss, and enhance heat transfer. Adding a V-shaped reflector directly below the heat pipe can allow the lost solar radiation to be absorbed by the heat pipe, thereby improving the absorption capacity of the collector.

Claims

1. A highly efficient sun-chasing, two-end condensing parabolic solar heat pipe collector, characterized by: The heat pipe collector includes multiple glass cover plates, a flat heat absorbing plate, multiple heat pipes, a V-shaped reflector, a rotating shaft, a stepping motor, a base, a disc, and an air flow channel; the heat pipe is coated with black nickel material, and the heat pipe is a parabolic heat pipe with symmetrical condensation at both ends, and the parabola opens upward; the two ends of the parabola are condensation sections, and the parabola diameter to the vertex is the evaporation section; the space between the inner and outer diameters of the heat pipe is vacuum, and each heat pipe is fixed to the center line of the base with support keys at equal distances; the condensation section is surrounded by a flat heat absorbing plate package to form The air flow channel has a cold air inlet at one end and a hot air outlet at the other end; the condensing sections are arranged side by side in the air flow channel; the outer surface of the flat-plate heat absorbing plate is provided with a selective absorption coating, and the outer side of the flat-plate heat absorbing plate is surrounded by a glass cover plate, which can transmit visible light and block far infrared rays; the heat pipe collector is placed on a base, and a V-shaped reflective plate is provided on the base; a rotating shaft is installed under the base, and the rotating shaft is connected to a stepper motor, and the stepper motor is installed in a circular disc, which is a hollow circular disc.

2. The high-efficiency, sun-chasing, two-end condensing parabolic solar heat pipe collector according to claim 1 is characterized in that: The focal length of the heat pipe is 64 mm, the parabola opening width is 250 mm, and the parabola equation is y=x 2 / 2.

3. The high-efficiency, light-chasing, two-end condensing parabolic solar heat pipe collector according to claim 2 is characterized in that: The V-shaped reflector is placed directly below each heat pipe, with the top edge of the V-shaped reflector coinciding with the projection of the heat pipe axis onto the base, and the two end lines being in the middle of the two heat pipes and perpendicular to the surface of the base. The solar radiation missed by the gaps between the heat pipes is reflected by the V-shaped reflector to the heat pipe and absorbed again.

4. The high-efficiency, sun-chasing, two-end condensing parabolic solar heat pipe collector according to claim 3 is characterized by: The driver of the stepper motor adopts A4988, and its step angle is 90°. According to the solar hour angle, 0° is calculated at noon, and it moves 15° per hour. Before 9 o'clock, the collector faces east. At 9 o'clock, the stepper motor rotates the collector 90° clockwise, and at 15 o'clock it rotates another 90° clockwise.

5. The high-efficiency, sun-chasing, two-end condensing parabolic solar heat pipe collector according to claim 4 is characterized in that: A glass cover plate capable of covering the entire heat collector is arranged above the two air flow channels.

6. The high-efficiency, sun-chasing, two-end condensing parabolic solar heat pipe collector according to claim 5, is characterized in that: The flat plate heat absorbing plate is coated with a Ta2O5 coating, an A-Si:H coating, a TEMP coating, and a TiO2-A coating; The thickness of the Ta2O5 coating is 150nm, the thickness of the A-Si:H coating is 78.67nm, the thickness of the TEMP coating is 10.29nm, and the thickness of the TiO2-A coating is 31.04nm; the Ta2O5 coating, the A-Si:H coating, the TEMP coating, and the TiO2-A coating are composited together to form a selective absorption coating.

7. The high-efficiency, sun-chasing, two-end condensing parabolic solar heat pipe collector according to claim 6, is characterized in that: The heat pipe has an inner diameter of 16 cm and an outer diameter of 18 cm. Flat heat absorbing plates are used around the condensing section of the heat pipe to form an air flow channel with a length of 280 cm, a width of 42 cm, and a height of 51 cm.

8. The high-efficiency, sun-chasing, two-end condensing parabolic solar heat pipe collector according to claim 7, is characterized in that: There are nine heat pipes.

9. The high-efficiency, sun-chasing, two-end condensing parabolic solar heat pipe collector according to claim 8, characterized in that: The heat collection method of the efficient tracking type two-end condensing parabolic solar heat pipe collector: Heat is absorbed by a combination of a flat-plate heat absorber and a heat pipe. The heat pipe adopts a condensing parabolic heat pipe with symmetrical ends. The flat-plate heat absorber is located outside the condensing section of the heat pipe, and the heat pipe evaporation section and the flat-plate heat absorber are used to absorb heat together. As the solar hour angle changes, the stepper motor drives the collector to chase the light through the shaft. At sunrise, the collector faces east. At 9 a.m., the collector rotates 90 degrees clockwise. At 3 p.m., the collector rotates 90 degrees clockwise and faces west. Solar radiation penetrates the glass cover and radiates to the evaporation section of the heat pipe and the flat-plate heat absorber. The heat exchange medium water in the heat pipe is heated and vaporized and enters the two sets of condensing sections. The flat-plate heat absorber absorbs the solar energy radiated to the air flow channel. Cold air enters from the air flow channel and is heated by the condensing section of the heat pipe and the flat-plate heat absorber, and the hot air flows out from the hot air outlet. The V-shaped reflector changes the path of solar radiation that leaks between the heat pipes and reflects it to the evaporation section of the heat pipe, heating the heat exchange medium in the heat pipe; the condensation section improves the heat exchange efficiency by turbulence in the air flow channel.

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