Solar fixed-focus concentrator, solar fixed-focus concentrating photovoltaic power generation device, and solar fixed-focus concentrating thermal collection device

Abstract

A solar fixed-focus (high-power) concentrator (9), a solar fixed-focus concentrating photovoltaic power generation device, and a solar fixed-focus concentrating thermal collection device. N light-splitting tubes (1) are arranged and combined into one module to serve as a light-splitting mirror (2), which is configured to split large-area incident sunlight (4) into n fine light beams. Each light-splitting tube (1) has a guide tube (301) which is configured to emit the fine light beams to a flattening mirror (10). After the fine light beams are converted into quasi-parallel light beams by means of the flattening mirror (10), the quasi-parallel light beams are emitted to a target light-receiving area (303) at the same fixed position, so as to form fixed-focus concentration. A high-precision expensive support and a complex sun tracking system are not required. The solar fixed-focus concentrator has a simple structure and few parts, and is easily manufactured and easily mounted, and is light, thin and durable. Compared with trough concentration devices in existing sun tracking systems having the lowest costs, the present invention has an apparatus purchase cost reduced by at least 25%. The present invention has the beneficial effect whereby solar energy can also be collected and utilized on cloudy days, and has the more beneficial effect whereby the solar fixed-focus concentrator (9) can be widely applied to concentrating photovoltaic and solar thermal power generation techniques, thereby improving the photoelectric conversion efficiency and promoting the development and utilization of solar energy.

Description

Solar fixed-focus concentrator and photovoltaic power generation and heat collection device Technical Field

[0001] The present invention relates to optical elements / systems, specifically to the technical field of static concentrators in non-imaging optics, and particularly to a solar fixed-focus concentrator and a photovoltaic power generation device and a heat collection device thereof. Background Art

[0002] As an inexhaustible and renewable energy source, the full utilization of solar energy can effectively mitigate global warming and contribute to sustainable development. Solar thermal collectors, which concentrate sunlight onto point or linear solar collectors, generate high-temperature heat for heating, thermal energy storage, and power generation. This facilitates low-cost thermal storage and improves the stability of renewable energy-based power grids. Traditional concentrators, such as parabolic troughs and dish concentrators, are commonly used in solar thermal collectors. These lenses and reflectors continuously modulate the propagation phase of sunlight based on their refractive index and spatial position, inevitably requiring high-precision support and complex sun tracking systems, which undoubtedly increases the cost and complexity of solar thermal power plants.

[0003] Current flat-plate silicon photovoltaic cell power generation devices, which do not require a tracking system, are technologically mature and highly reliable. However, the area of ​​the photovoltaic cell is the same as the area exposed to sunlight, resulting in a large number of cells, low photovoltaic cell utilization, and high power generation costs. To fully utilize photovoltaic power generation, it is possible to concentrate sunlight from a wider range into a smaller area, thereby collecting more sunlight during periods of low sunlight intensity. The use of concentrating photovoltaic (CPV) technology is a future trend in solar power generation.

[0004] Concentrating photovoltaic (CPV) technology converts concentrated sunlight directly into electricity using highly efficient photovoltaic cells. CPV is the most prominent example of concentrated solar power generation (CSP) technology. Crystalline silicon cells and thin-film cells are the first and second generation solar energy technologies, respectively, and both have been widely adopted. Concentrating solar power, which uses optical components to concentrate sunlight for power generation, is the third generation of solar power generation, a trend in future development. Compared to traditional solar power generation methods, concentrating solar cell efficiency can reach up to 60%, while the internationally highest efficiency level for conventional photovoltaics is only 26.81%, according to recent reports. While CSP technology offers many advantages, it also faces numerous challenges and limitations. One such issue is the high cost of lenses and their associated tracking systems. Lenses require extremely high manufacturing precision and high-quality materials, contributing to the relatively high cost of CSP systems.

[0005] A Chinese invention patent (CN101969078B) authorizes a "selective concentrating optical device." While thin and lightweight, it doesn't require a sun-tracking system. However, its light-collecting efficiency is only 20-40%, and its concentration ratio is less than 5x, representing low-concentration. 60-80% of the light energy isn't effectively collected and utilized. Furthermore, its "light-frequency conversion film" is susceptible to aging and has a short service life. To fully utilize solar power generation, a Chinese invention patent (CN101359697B) designs a "solar low-concentration concentrator." This reduces the number of solar cells required by conical light, significantly increasing solar cell power generation per unit area. However, this device is a thick, large, and bulky trapezoidal structure, making it unsuitable for rooftop photovoltaic panels. Furthermore, its uneven light spot reduces output power and can easily cause hot-spot effects, which can damage solar cell modules.

[0006] Optical metasurfaces are planar structures composed of artificial atoms at the subwavelength scale. Metasurface concentrators are cutting-edge concentrating technologies that are expected to replace traditional lenses and mirrors to effectively capture broadband, wide-angle sunlight without the need for complex sunlight tracking systems to generate cost-effective electricity. They are more suitable for the development of compact platforms than curved lenses or mirrors used in solar thermal collection systems. However, the process of preparing large-area, high-precision nanoimprint templates using traditional electron beam lithography (EBL) technology has low processing efficiency, long processing time, and high processing costs. If large-scale applications are to be achieved, even application demonstrations still have a long way to go in research and development.

[0007] In summary, how to concentrate light without tracking, at low cost and at high magnification has always been a global problem that researchers in the solar energy industry from all over the world have been tackling.

[0008] Summary of the Invention

[0009] One of the purposes of the present invention is to provide a high-power concentrator, a solar fixed-focus concentrator, so as to concentrate solar energy at a high power rate without tracking and at low cost.

[0010] The second object of the present invention is to provide a solar fixed-focus concentrating photovoltaic power generation device, so as to collect solar energy for photovoltaic power generation without tracking, at low cost and at high magnification.

[0011] The third object of the present invention is to provide a solar fixed-focus concentrating heat collecting device, so as to collect solar energy for heat collection in a tracking-free, low-cost and high-efficiency manner.

[0012] To achieve one of the above purposes, the technical solution adopted by the present invention is as follows.

[0013] The present invention provides a solar fixed-focus concentrator, which is characterized by:

[0014] ① n beam splitters are arranged and combined into a beam splitter array module, which is referred to as a beam splitter in the present invention. The beam splitter is used to split a large area (nS1) of incident sunlight received at its upper end (i.e., input end) into numerous thin beams (with very small divergence angles), where n is ≥ 5, 25, 50, 100, 500, 1000, or 5000. Process tests have shown that the greater the number of beam splitters n, the higher the production efficiency. However, if the number exceeds 1000, the scrap rate will increase.

[0015] ② The beam splitter is provided with (e.g., n) guide tubes, the inlet ends of the guide tubes being (e.g., respectively) connected to the beam splitter tubes, and the outlet ends of the guide tubes extending (e.g., respectively) to (e.g., n different positions) predetermined projection points (e.g., to the focal point of the flattening mirror) and oriented in a specific direction (e.g., the direction of a line connecting the center points of each guide port and the center point of the flattening mirror); the light outlets of the guide tubes, referred to as guide ports in the present invention, are used to adjust (i.e., change) the emission direction of the branched light beams;

[0016] ③ The fine branch light beam is injected into the guide tube from the lower end of the beam splitter, and then propagates from the guide tube to the predetermined projection point (i.e., the emission point of the fine branch light beam) and is emitted from the guide port;

[0017] ④ The (e.g., n) thin light beams emitted from the plurality (e.g., n) predetermined projection points and their guide ports are each directed through space to a target light-receiving area of ​​a smaller range (area S2) at the same fixed position (including being directed directly or indirectly through a guide mirror to the target light-receiving area, which may be a point or a line), thereby forming a fixed-focus concentrated light. Because the focal position is fixed, the present invention refers to it as a fixed-focus concentrated light.

[0018] ⑤ The height of the beam splitter is L, and the diameter of the light entrance is D; the length of the guide tube is C, and the diameter of the light exit (i.e., the guide port) of the guide tube is d; the area of ​​the light entrance of a single beam splitter is S1, and the area of ​​the light receiving area is S2; (preferably) L ≤ 1 mm or 2 mm or 4 mm or 8 mm or 16 mm or 32 mm or 64 mm or 128 mm or 256 mm or 512 mm, D ≤ 1 mm or 2 mm or 4 mm or 8 mm or 16 mm or 32mm or 64mm or 128mm or 480mm, C ≤ 0.1mm or 1mm or 2mm or 4mm or 8mm or 16mm or 32mm or 480mm, d ≤ 0.25mm or 0.5mm or 1mm or 2mm or 4mm or 8mm or 16mm or 32mm or 64mm, D / d ≥ 25 or 10 or 5 or 3.7 or 1.7 or 1, nS1 / S2 ≥ 500 or 100 or 50 or 25 or 10 or 3;

[0019] It is important to emphasize that in order to avoid the high temperature caused by the large value of D / d, which may burn out the guide tube and the tip made of the material resistant to medium and low temperatures (80-200°C), D should be 2 / d 2 (value) is set to 3-22, preferably 3-9. At this time, the narrow beam emitted from the guide tube and the tip has a focusing multiple of less than 10 times and a low energy flux density, so cheap ordinary materials such as coated aluminum tubes can be used. Studies have shown that D 2 / d 2 When D / d is 3-22, the guide tube made of the medium and low temperature resistant material will not be burned, and the solar fixed-focus concentrator made of it is resistant to aging, has a long service life, and has a high cost performance; in other words, when D / d is 4.69≥D / d≥1.73, the guide tube made of the medium and low temperature resistant material will not be burned, and the solar fixed-focus concentrator made of it has a high cost performance; on the contrary, if D 2 / d 2 ≥25, the guide tube and tip must be made of high temperature resistant (200-1000℃) material;

[0020] ⑥ Both the beam splitter and the guide tube are optical channels with high reflectivity and / or total reflection characteristics (i.e., 100% reflectivity), wherein the reflectivity is ≥ 90%, 95%, 97%, 99%, 99.9%, or 99.99%. Research has shown that when the reflectivity is below 95%, the light focusing efficiency is very low, while when it is above 99%, the manufacturing cost is very high. The most suitable reflectivity is 95%-99%.

[0021] The light splitting tube or the guide tube can be a hollow tube or a transparent solid tube or other light channel.

[0022] Preferably, the solar fixed-focus concentrator is characterized in that the n guide openings at different positions are all aligned with the same light-receiving area, either directly or indirectly (after reflection / refracting) through the guide mirror. This allows the thin beams (emitted from the guide tube and its guide opening) to become directional beams, all (directly or indirectly) directed toward the light-receiving area, thereby achieving fixed-focus concentrator light.

[0023] Preferably, the solar fixed-focus concentrator is characterized in that a guide mirror is provided in front of the guide port, the thin light beams emitted from the guide port are directed toward the guide mirror, and are all converged into the light receiving area after being adjusted in direction by the guide mirror.

[0024] Preferably, the solar fixed-focus concentrator is characterized in that: the guide tubes are a number of straight tubes parallel to each other, and their guide ports are uniformly oriented towards a Fresnel lens-type guide mirror whose surface is covered with micro lenses (layers), so as to further converge and shape the fine light beams, and arrange them into (a group of) roughly parallel fine light beams (which can be simply referred to as flattened light beams) and inject them into (preferably vertically into) the guide mirror; after the guide mirror refracts and deflects the flattened light beams, they are all focused on the light receiving area; wherein, the function of the micro lenses (layers) is to further converge and correct the fine light beams to make them closer to parallel light.

[0025] Preferably, the solar fixed-focus concentrator is characterized in that the beam splitter is a conical beam splitter (i.e., a light cone or light funnel) with a taper D / L ≤ 0.75 or 0.35, which is used to split, fold, and contract the incident sunlight received at its upper end into a high-energy flux density, narrow beam—a high-energy beam—which is then emitted from the pointed tip of the conical beam splitter into the guide tube, which then forms the narrow beam (with a very small divergence angle) into a light cone. The light cone is a non-imaging element. After light enters the large opening (i.e., the large end) of the light cone, it undergoes several reflections before being emitted from the small opening (i.e., the small end) without generating backreflections. To reduce light loss, the height L of the light cone should be as short as possible to minimize the number of light reflections within the cone. The area ratio of the large opening to the small opening of the light cone should be as large as possible. Research shows that the smaller the taper D / L, the fewer times the light will reflect in the spectrometer, the more direct the light propagation path will be, and the less light loss will be. The best taper D / L is ≤ 0.25 or 0.10.

[0026] The above-mentioned solar fixed-focus concentrator has a simple structure, is easy to be injection molded (plate-type), easy to be press molded (plate-type), easy to be 3D printed (plate-type), easy to be polished, and easy to be coated to produce a reflective layer with high reflectivity.

[0027] Research has found that the thin light beam emitted from the guide tube and its light outlet will be scattered. If it is not flattened, the light energy gathered to the farther light receiving area will be less than 50%, resulting in a high light loss rate.

[0028] Preferably, the solar fixed-focus concentrator is characterized by: (At least) one concave mirror or lens (capable of converting scattered light into a quasi-parallel beam) is provided in front of (including the front side of) each guide port or in front of (including the front side of) the tip of each conical beam splitter. Both can be collectively referred to as flattening mirrors based on their purpose. The guide port or tip is positioned on the focal plane of the flattening mirror, so that the fine branched light beams emitted from the guide port or tip and their scattered light constitute a point light source located on the focal plane of the flattening mirror. The flattening mirror is used to further converge and shape the fine branched light beams (of the point light source) incident thereon into quasi-parallel beams (with extremely small divergence angles), which are then emitted (directly or indirectly) toward the light-receiving area in the form of quasi-parallel beams, thereby achieving precise focusing and reducing scattered light loss. Preferably, the quasi-parallel light beams are directed indirectly toward the light-receiving area after being adjusted in direction by the (prepared) guide mirror (e.g., a Fresnel lens).

[0029] It should be emphasized here that in the above-mentioned innovative technical solution in which the guide opening or tip (mouth) is positioned in the focal plane region of the flattening mirror, the light emitted from the guide opening or tip (mouth) toward the flattening mirror constitutes a point light source on its focal plane. This point light source is forward-projected scattered light. Regardless of how the sun moves, it is always scattered light projected forward from a point. The diameter of its projected light spot does not exceed the diameter of the flattening mirror. In other words, the size of the projected light spot does not exceed the range of the flattening mirror, and its projection direction remains essentially unchanged. In summary, the fixed-focus focusing principle of this technical solution is to first split and compress sunlight into a series of fixed, forward-projecting point light sources. Then, concave mirrors or lenses are used to transform (refract or reflect) the forward-projecting scattered light emitted by the point light source located on the focal plane (preferably at the focus) into a series of quasi-parallel light beams, which are then projected toward the target light receiving area at the same fixed position, thereby forming a fixed-focus focusing system. Research shows that the smaller the aperture of the guide port is, the better (aperture d≤1.5 mm is best), the closer the light emitted is to a point light source, and the more parallel the quasi-parallel light beam emitted from the flattening mirror is.

[0030] Research also shows that in order to maximize the parallelism of the quasi-parallel light beam, reduce the manufacturing difficulty, and reduce the manufacturing cost, the size of the flattening mirror should be appropriately enlarged and the number should be appropriately reduced. It is best that the diameter of a single flattening mirror is ≤ the diameter of the light entrance of a single conical beam splitter; it is best that the distance from the flattening mirror to the guide port or the tip (mouth) is ≤32.2mm; it is best (to use a beam combiner) to combine multiple thin light beams into one, and emit them from the same guide port (in the form of the same point light source) to the same flattening mirror.

[0031] In order to improve and perfect the solar fixed-focus concentrator, technical improvements and improvements can be made from the following aspects ① to ⑩.

[0032] Ideally, C / d ≥ 3.22; ideally, the section of the guide tube near the guide opening is a straight tube (preferably thin, 0.10-32mm) with a length of C1 (not curved, not too long, preferably 0.10-5mm; too long will result in significant light loss and extremely high costs) - this section of (thin) straight tube can be called a straight guide tube; the ratio of the length C1 of the straight guide tube to the diameter d of its (thin) guide opening, C1 / d ≥ 3.22. Research has shown that if the tube diameter is too large / thick, not straight, or too short, and the tube length to tube diameter ratio C1 / d is too small, the branched light beam will change its direction as the sun moves, easily scattering, resulting in a large divergence angle and difficulty in precise focusing. Conversely, the thinner the guide tube, the more likely the branched light beam will undergo total internal reflection within it, reducing propagation light loss. Research has shown that a guide tube diameter d ≤ 1.5mm minimizes light loss.

[0033] Preferably, the solar fixed-focus concentrator is characterized by the beam splitter and guide tube being integrated into one, for example, a single straight light guide tube. The straight light guide tube is an optical fiber with a core diameter ≤ 1.5 mm (preferably less than 0.5 mm), a thin cladding, and a height (L) ≤ 16 mm (preferably less than 8 mm). Multiple optical fibers are arranged in parallel to form a beam splitter array module—the beam splitter. The upper and lower ends of the optical fibers are preferably ground or polished. Research has shown that the thinner the straight light guide tube, the shorter it can be, and the thinner the beam splitter can be. Currently, optical fibers capable of transmitting strong light and high energy are manufactured from high-purity quartz with a purity of up to 99.999%, which is very expensive. A 1 mm core diameter optical fiber can cost as much as RMB 100 per meter. Using thin, short optical fibers as light guide tubes can greatly improve the cost-effectiveness of the solar fixed-focus concentrator.

[0034] Preferably, the solar fixed-focus concentrator is characterized in that: the guide tube is a light channel such as a hollow tube or a solid tube with an aperture d of 0.1-5 mm, and preferably, the end surface of the guide port is smooth and flat. Research has shown that when the aperture d of the guide tube is less than 0.1 mm, the emitted fine beams will diffract, resulting in a large amount of scattered light, which is not conducive to focusing. Conversely, when the aperture d of the light outlet of the guide tube is greater than 5 mm, the emitted fine beams will also produce a large amount of scattered light, which is not conducive to focusing. Therefore, the optimal value range of the aperture d of the light outlet of the guide tube is 0.1-5 mm. Research has also shown that when the guide tube is a solid tube, the end surface of the guide port must be polished and flat, otherwise severe scattering will occur. Research has found that when the guide tube is a hollow tube, its guide port does not have a solid end surface and severe scattering will not occur. Therefore, in order to simplify the production process and avoid polishing, the guide tube is preferably a hollow tube.

[0035] Alternatively, the solar fixed-focus concentrator is characterized in that the light-entry end of the beam splitter is a honeycomb polygon, such as a hexagon, tetrahedron, or trihedron, with very small gaps between adjacent polygons. A circular shape is also acceptable, but the gaps are too large, resulting in a slightly smaller area for effectively receiving sunlight. The beam splitter can be a hexagon, tetrahedron, triangular prism, or wedge with rounded edges.

[0036] Option 2 is that the solar fixed-focus concentrator is characterized by: the light inlet of the beam splitter is a shallow pit (a pot-bottom-shaped port with high edges and a low center) or a raised port (preferably a convex lens port); the shallow pit should not be too deep, as this makes dust difficult to clean; a ratio of depth to thickness of 0.15-0.65 is appropriate; the raised port should not be too convex, as this makes it difficult to clean dust from the gap. Theoretically, an open port is best for the beam splitter, but dust easily enters an open port, which can easily clog the tip and make it difficult to clean. For this reason, a shallow pit or raised port is employed. This prevents sunlight from being lost due to total reflection at higher angles of incidence compared to a flat surface, thereby increasing the maximum angle of sunlight reception. This increases the angle of incidence, allowing the incident sunlight to be fully reflected and transmitted as much as possible within the conical beam splitter. Tests have shown that when the solar fixed-focus concentrator described in the present invention is used for photovoltaic panel power generation, if the beam splitter's light entrance is flat, power generation drops sharply when the incident angle exceeds 45 degrees. Conversely, if the beam splitter's light entrance has a shallow pit, power generation only begins to significantly decline when the incident angle exceeds 65 degrees. This shows that the shallow pits and raised structures on the beam splitter's surface facilitate cleaning and increase the amount of sunlight it receives.

[0037] Option ② may also be the solar fixed-focus concentrator, characterized in that the upper surface of the beam splitter is provided with many shallow pits or protrusions (preferably micro-protrusion light-collecting covers) (preferably corresponding to the light inlet of the beam splitter tube) to reduce total reflection.

[0038] Preferably, the beam splitter and the guide tube are combined into a single (very thin) straight light guide tube. In this way, each of the thin light beams is straightened by the straight light guide tube into a thin light beam with a precise emission direction, which does not move with the movement of the sun.

[0039] Option ② may be the solar fixed-focus concentrator, characterized in that: an anti-reflection transparent protective layer is provided on the upper end of the beam splitter to prevent dust from blocking the beam splitter tube and the guide tube, so as to remove dust, bird droppings and other dirt thereon; or a transparent matte layer is provided on the beam splitter to absorb diffuse light on cloudy days to gather weak light energy.

[0040] Optionally, ③ the solar fixed-focus concentrator is characterized in that: the predetermined projection point is a point (such as a focus) on the focal plane of the flattening mirror, or / and the specific direction is the direction of the line connecting the center point of the guide port to the center point of the flattening mirror.

[0041] Preferably, the solar fixed-focus concentrator is characterized by: multiple beam splitters are assembled into a group and laid flat on the same guide mirror. The beam splitter is composed of numerous beam splitters arranged in an array, making it difficult to manufacture thin and large modules exceeding 100mm x 100mm. To facilitate production, a technical measure is adopted in which multiple beam splitters are assembled into a group and the small pieces mounted on the same guide mirror are assembled into a large piece.

[0042] Option (4) is that the solar fixed-focus concentrator is characterized by: a diffuse (reflective) object (such as a diffuse reflector, white wall, or other diffuse reflective object) is positioned near the beam splitter to increase the brightness of the area (where the beam splitter is located), thereby enabling concentrated light (in the light receiving area) even on cloudy days. Furthermore, a reflector is preferably positioned near the beam splitter to reflect direct sunlight from the vicinity onto the beam splitter, thereby increasing light capture efficiency.

[0043] Preferably, the solar fixed-focus concentrator is characterized in that the sum of the height of the beam splitter tube and the length of the guide tube L+C ≤ 128 mm; in this way, light loss can be reduced and the solar fixed-focus concentrator suitable for use with rooftop photovoltaic panels can be produced.

[0044] Preferably, the solar fixed-focus concentrator is characterized in that the guide port is a light outlet with a flat end surface, so that the emitted thin beams have a very small divergence angle. Conversely, if the end surface of the guide port is uneven, the emitted thin beams will have a large divergence angle, which is not conducive to the flattening mirror converting the light beams into quasi-parallel beams.

[0045] Option ⑤ is that the solar fixed-focus concentrator is characterized in that the diameter of a single flattening mirror is ≤ the diameter of the light entrance of a single conical beam splitter.

[0046] Option ⑥ is that the solar fixed-focus concentrator is characterized in that: the angle between the axis of the flattening mirror and the horizontal line (for example, from left to right or from edge to center) decreases successively; or, the angle α between the direction of the guide port and the horizontal line (for example, from left to right or from edge to center) increases successively; or, the distance from the flattening mirror and the guide port to the beam splitter (for example, from left to right or from edge to center) shortens successively.

[0047] Option 7 is that the solar fixed-focus concentrator is characterized by a micro-reflector disposed in front of the guide opening, configured to deflect the thin branched light beams toward the concave surface of the concave mirror, where they are reflected by the concave surface into quasi-parallel beams that are then directed toward the light-receiving area. This prevents some light in the central region from being directly scattered without being converted into quasi-parallel beams by the concave surface. In other words, the reflector is disposed in front of the guide opening to block light from the point source at the focal point from being directly emitted forward, and instead reflects and directs it toward the concave mirror, thereby further concentrating the generated parallel beams.

[0048] Optionally, the solar fixed-focus concentrator is characterized in that the beam splitter, the guide tube or nozzle, the flattening mirror, the guide opening or nozzle opening on the focal plane, the reflector, and other components (combined together) form a beam splitting and flattening module capable of outputting a quasi-parallel beam, facilitating a single-step molding process (injection molding or stamping). The reflector is preferably secured to the guide tube using a transparent fastener such as a transparent nut.

[0049] Preferably, the solar fixed-focus concentrator is characterized in that the beam splitter is a wedge-cone beam splitter, which is convenient for processing and manufacturing and for combined use.

[0050] Preferably, the light outlet of the guide tube and the flattening mirror are located at least 0.3√nD (i.e., zero point three times the square root of nD) away from the light receiving area. This prevents the high temperature of the light receiving area from damaging the light outlet of the guide tube and the flattening mirror, facilitates processing and manufacturing, and facilitates total internal reflection of the flattening mirror, thereby reducing light loss.

[0051] In order to further improve and perfect the solar fixed-focus concentrator, technical improvements and improvements can be made from the following aspects.

[0052] Preferably, ① the solar fixed-focus concentrator is characterized in that the axes of the plurality of flattening mirrors each pass through the same light-receiving area.

[0053] Option ② is that the solar fixed-focus concentrator is characterized in that the angle between the line connecting the center point of the guide port to the center point of the flattening mirror and the axis of the flattening mirror is an acute angle, so that the quasi-parallel light beam reflected from the flattening mirror avoids the guide tube and is directed toward the light receiving area.

[0054] Option ③ is that the solar fixed-focus concentrator is characterized in that the distance from the flattening mirror to the guide port or the pointed mouth is ≤32.2 mm.

[0055] Optionally, (4) the solar fixed-focus concentrator is characterized in that a plurality of the thin light beams are bundled into one and emitted from the same guide port to the same flattening mirror in the form of the same point light source.

[0056] Option ⑤ is that the solar fixed-focus concentrator is characterized in that the branched light beams and their scattered light emitted from the plurality of guide ports are adjusted (i.e. refracted or reflected) into quasi-parallel light beams by the flattening mirror and then emitted toward the light receiving area through the air.

[0057] Option ⑥ is that the solar fixed-focus concentrator is characterized in that the guide port or the pointed mouth is arranged on the focal plane of the flattening mirror, so that the fine branch light beam and its scattered light emitted from the guide port or the pointed mouth constitute a point light source located on the focal plane of the flattening mirror.

[0058] Option ⑦ is that the solar fixed-focus concentrator is characterized in that the guide port or the pointed mouth is arranged on the focus of the flattening mirror, so that the thin branch light beam and its scattered light emitted from the guide port or the pointed mouth constitute a point light source located on the focus of the flattening mirror.

[0059] To achieve the second of the above objectives, the technical solution adopted by the present invention is as follows.

[0060] The present invention provides a solar fixed-focus concentrating photovoltaic power generation device, which is characterized by using (or including) any of the above-mentioned solar fixed-focus concentrators, and photovoltaic panels are installed in the light-receiving area and receive sunlight concentrated by the solar fixed-focus concentrator to generate electricity.

[0061] Research has found that the guide opening and flattening mirror, due to long-term outdoor use, are prone to dust accumulation, which can lead to reduced reflectivity and increased light loss. Preferably, the guide opening, flattening mirror, and photovoltaic panels are enclosed in a dustproof housing; the photovoltaic panels are equipped with heat sinks that dissipate heat outside the dustproof housing.

[0062] To achieve the third of the above objectives, the technical solution adopted by the present invention is as follows.

[0063] The present invention provides a solar fixed-focus concentrating heat collection device, characterized by using any of the aforementioned solar fixed-focus concentrators. The solar heat collection device is installed in the light-receiving area and receives sunlight concentrated by the solar fixed-focus concentrator to generate heat. The heat collection device can be a conventional solar heat collection device such as a solar heat collecting tube, a solar cooker, or a solar water heater.

[0064] In order to prevent dust from falling on the guide port and the flattening mirror, which would result in reduced reflectivity and increased light loss, it is desirable that the guide port, the flattening mirror and a local area of ​​the solar thermal collector be enclosed in a dustproof housing.

[0065] The beam splitter described in the present invention can be a circular tube, square tube, polygonal tube, flat tube, rectangular tube, or other special-shaped tube. The conical beam splitter described in the present invention refers to a light cone or light funnel, which can be either a transparent solid cone or a hollow cone. The aperture D and d described in the present invention are parameters indicating the size of the light inlet and light outlet. For a circular aperture, the aperture D and d refer to the diameter; for an elliptical aperture, the aperture D and d refer to the major axis; for a rectangular aperture, the aperture D and d refer to the long side or diagonal dimensions.

[0066] Compared with the prior art, the present invention has the following beneficial technical effects.

[0067] First, no tracking, high magnification: The innovative solar fixed-focus concentrator of the present invention uses the guide tube and its guide port and the flattening mirror and guide mirror to adjust the direction of light, and directs sunlight to the same fixed position, thereby forming a fixed-focus concentrator. The focusing point will not move with the movement of the sun, and no high-precision support and complex tracking sun system are required. The concentrating cost is low and solar energy can be concentrated at a high magnification.

[0068] Second, it is simple and reliable: the solar fixed-focus concentrator described in the present invention is light in weight, thin in thickness, uses less materials, has fewer parts, is easy to manufacture and install, is durable, stable and reliable.

[0069] Third, low cost: The use of the solar fixed-focus concentrating heat collection (power generation) device of the present invention eliminates the need for a solar tracking system, thereby reducing the equipment purchase cost by more than 25%, and the resulting beneficial technical and economic effects are very significant. In short, the large-scale application of the solar fixed-focus concentrator and its heat collection device described in the present invention will inevitably trigger a new energy revolution. In the past ten years, the photovoltaic industry has mainly relied on three aspects to reduce the cost per kilowatt-hour and reduce equipment investment: one is the experience curve, learning advanced technology; the second is the scale effect, which rapidly reduces costs; and the third is technological innovation. The effectiveness of the experience curve is already very low, and the scale effect cost reduction is also close to the "floor". Continuous technological innovation has become the most effective means to promote the upgrading and development of the photovoltaic industry and ultimately achieve grid parity. It should be noted that at this stage, it is very difficult for technological innovation to reduce the cost per kilowatt-hour by 1% or reduce equipment investment by 1%.

[0070] Fourth, solar energy can also be collected on cloudy days: On sunny days, the illumination intensity of direct sunlight is about 10,000 lux, while on cloudy days, the illumination intensity is much weaker, averaging 1,000-2,000 lux. Tests show that when the diameter D of the horn mouth of the beam splitter is ≤ 8 mm (especially when D ≤ 6 mm), the solar fixed-focus concentrator described in the present invention can collect diffuse light, especially when a diffuser plate is provided on the surface of the solar fixed-focus concentrator and in its vicinity, solar energy can also be collected and utilized on cloudy days. In this way, when there is no direct sunlight (i.e., only diffuse light) in the morning and evening on cloudy and sunny days, the present invention can also be used for photovoltaic power generation, and solar water heaters can also be used. In particular, the solar fixed-focus concentrator described in the present invention can be made into thin blocks like wall bricks and affixed to the exterior walls of buildings. In this way, it can be used for photovoltaic power generation on cloudy days, and solar water heaters can be used to produce hot water on cloudy days, and can also provide thermal insulation for buildings.

[0071] Fifth, high light capture efficiency: Compared to the Chinese invention patent (CN101969078B), "A Selectively Converging Optical Device," the present invention increases its light capture efficiency from 20-40% to 80-90%. This allows for cost-effective utilization of concentrating technology to boost solar cell efficiency, from 26.81% for traditional photovoltaics to 60% for concentrated photovoltaics (CPV), resulting in significant technical and economic benefits.

[0072] Sixth, it is particularly suitable for use as a skylight for existing light-guiding lighting systems: The solar fixed-focus concentrator described in the present invention is particularly suitable for use as a skylight for light-guiding lighting systems. For example, it is used in the Chinese utility model patent "A light-guiding tube skylight lighting system with energy-saving effect (CN212510948U)", so that natural light can be collected for lighting during periods of weak light and diffuse light such as cloudy days.

[0073] Seventh, it can be light and thin: Compared with the very thick and large "solar low-magnification concentrator" in the background technology, the solar fixed-focus concentrator described in the present invention can be made very light and thin. It can be made into thin plates / sheets of several millimeters to several centimeters according to customer needs. Therefore, it is particularly suitable for making roof photovoltaic tiles, road photovoltaic bricks, and wall photovoltaic stickers.

[0074] Eighth, the light-receiving area is evenly illuminated, no hot spot effect will occur, no damage to battery components, and low light loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] FIG1 is a top view schematic diagram of a solar fixed-focus concentrator formed by arranging and combining (122) conical beam splitters used in the present invention (Example 1).

[0076] FIG2 is a schematic diagram of the longitudinal cross-section structure at position AB in FIG1 .

[0077] FIG3 is a schematic diagram of the longitudinal cross-sectional structure of a solar fixed-focus concentrator using a micro-convex lens (i.e., a flattening mirror) in the present invention (Example 4).

[0078] FIG4 is a schematic diagram of the longitudinal cross-sectional structure of another solar fixed-focus concentrator using a micro-convex lens (i.e., a flattening mirror) in the present invention (Example 4).

[0079] FIG5 is a schematic diagram of a miniature convex lens (i.e., a flattening lens), a guide tube, a reflector, and an optical path used in FIG3 and FIG4.

[0080] FIG6 is a schematic diagram of the longitudinal cross-sectional structure of a concave mirror (i.e., a flattening mirror) in the present invention (Example 4).

[0081] FIG7 is a schematic diagram of the longitudinal cross-sectional structure of a solar fixed-focus concentrator using the concave mirror (i.e., flat mirror) in FIG6 .

[0082] FIG8 is a schematic diagram showing the positional relationship and optical path of a micro reflective cup (ie, a flattening mirror) and a corresponding section of a guide tube in the present invention (Example 4).

[0083] FIG9 is a schematic diagram of the longitudinal cross-section structure in FIG8 .

[0084] FIG10 is a schematic diagram of the longitudinal cross-sectional structure of some micro concave (reflecting) mirrors (i.e., flattening mirrors) in FIG8 applied to a solar fixed-focus concentrator according to the present invention.

[0085] FIG11 is a schematic diagram of the longitudinal cross-sectional structure of a solar fixed-focus concentrator in the present invention (Example 3).

[0086] FIG12 is a schematic diagram of a top view of a solar fixed-focus concentrator in the present invention (Example 2).

[0087] FIG13 is a schematic diagram of the longitudinal cross-sectional structure at position YZ in FIG12 .

[0088] FIG14 is a schematic diagram of the longitudinal cross-section structure of a solar fixed-focus concentrator in the present invention (Example 5).

[0089] FIG15 is a schematic diagram of the longitudinal cross-sectional structure of a beam splitter used in FIG14 .

[0090] FIG16 is a schematic diagram of the longitudinal cross-sectional structure of a solar fixed-focus concentrating photovoltaic power generation device in the present invention (Example 6).

[0091] FIG17 is a schematic diagram of the longitudinal cross-sectional structure of a solar fixed-focus concentrating heat collecting device in the present invention (Example 7).

[0092] FIG18 is a schematic diagram of the external structure of a tapered beam splitter used in the present invention (embodiment).

[0093] FIG19 is a schematic diagram of the longitudinal cross-sectional structure of the tapered beam splitter in FIG18 .

[0094] FIG20 is a schematic diagram of the longitudinal cross-sectional structure in which the angles α between the seven guide tubes on the left half of FIG10 and the horizontal line increase successively from left to right.

[0095] Figure 21 is a schematic diagram of the longitudinal cross-sectional structure in which the angles α between the 7 guide tubes on the left half of Figure 10 and the horizontal line increase from left to right, and the angle between the axis of the concave mirror and the horizontal line decreases from left to right.

[0096] Figure 22 is a schematic diagram of the longitudinal cross-sectional structure of the concave mirror in Figure 21 with the height decreasing from left to right.

[0097] FIG23 is a schematic structural diagram of a tapered beam splitter with a bent tube that can be used in the present invention.

[0098] FIG24 is a schematic structural diagram of a wedge-cone beam splitter used in the present invention.

[0099] FIG25 is a schematic diagram of the cross-sectional structure in which a reflective mirror is provided in front of the guide port in the concave mirror in FIG6 .

[0100] FIG26 is a schematic diagram of the longitudinal cross-sectional structure of an entire light splitting and flattening module used in the present invention (Embodiment 8).

[0101] FIG27 is a schematic diagram of the longitudinal cross-sectional structure of a reflector used in FIG26 fastened to a guide tube.

[0102] Explanation of the accompanying numbers: 1-beam splitter, 101-tip, 102-(beam splitter) light inlet, 103-lens, 2-beam splitter, 301-guide tube, 302-reflecting layer, 303-light receiving area, 304-axis, 305-horizontal line, 306-point light source, 307-guide port, 308-focal plane, 4-sunlight, 401-scattered light, 402-fine beam, 403-quasi-parallel beam, 5-bend pipe, 6-photovoltaic panel, 601-heat sink, 7-reflector, 701-fastener, 8-astigmatism cavity wall, 9-solar fixed-focus concentrator, 10-flattening mirror, 11-light guiding straight tube, 12-Fresnel lens, 13-shallow pit, 14-collecting tube, 15-beam splitting and flattening module as a whole, 16-dustproof shell, 17-connection direction. DETAILED DESCRIPTION

[0103] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0104] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as "upper", "lower", "inner", "inside", "front", "back", "left", "right", and "horizontal line" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention.

[0105] It should be noted that, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, "connected" can refer to optical connection or direct connection. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0106] Example 1.

[0107] A rectangular solar fixed-focus concentrator 9 is produced.

[0108] A honeycomb (light cone array) beam splitter 2 measuring 128 mm × 83 mm × 16 mm, as shown in Figures 1 and 2, is fabricated from optical-grade PC (polycarbonate) or aluminum. For example, n conical beam splitters 1 are arranged and combined to form a honeycomb beam splitter 2, as shown in Figure 23, where n is 122. Another example is n wedge-cone beam splitters 1, as shown in Figure 24, are arranged and combined to form a beam splitter 2. The flared (i.e., large-end) light inlet 102 of each conical beam splitter 1 is oriented toward the upper end of the beam splitter 2, collecting sunlight 4 across a wide range of angles and splitting and folding the received (large-area) incident sunlight 4 into numerous branched light beams (preferably, n branched light beams). The pointed tip 101 (i.e., output end) of each conical beam splitter 1 is oriented toward the lower end of the honeycomb beam splitter 2. The diameter D of a single trumpet-shaped light inlet 102 (preferably a shallow pit light inlet) is set to be less than 8 mm, the diameter of a single pointed tip 101 is set to be less than 1 mm, and the height L of a single tapered beam splitter 1 is set to be less than 15 mm.

[0109] At the lower end of the honeycomb-type spectroscope 2, each of the tips 101 is connected to a guide tube 301 (the diameter of the light outlet is equal to the diameter of the tip), and the guide ports 307 of the guide tubes 301 are set at predetermined projection points at different positions, and all of them are directed (including indirectly directed through reflectors) to a target light receiving area 303 at the same fixed position (i.e., the specific direction); the light receiving area 303 is set about 150 mm below the center of the honeycomb-type spectroscope 2; Sunlight 4 of a certain area enters through the trumpet-shaped light inlet 102, is reflected multiple times by the conical beam splitter 1, and converges to the pointed tip 101, and is emitted from the light outlet of the guide tube 301 connected thereto. The n fine light beams 402 (like n miniature spotlight beams) emitted from the light outlet of the guide tube 301 with very small divergence angles (i.e., high straightness) are all emitted (preferably from a medium-free space such as air or vacuum) toward the same light-receiving area 303, thereby forming a fixed-focus concentrated light. The reason for recommending that the fine light beams 402 be emitted from a distance toward the light-receiving area 303 is, firstly, to save material required for the guide tube 301, secondly, to reduce reflected light loss, thirdly, to prevent the light outlet of the guide tube 301 (i.e., the guide port 301) from being too close to the light-receiving area 303 and being burned, and fourthly, to further improve the concentration. In other words, during specific implementation, the technical requirement that the guide port 301 be spaced away from the light-receiving area 303 should be complied with.

[0110] It is important to emphasize that the guide tube 301 is preferably made of a quartz optical fiber bundle. Because quartz optical fiber is expensive, the length C of the guide tube 301 should be as short as possible to reduce transmission light loss and thus lower costs. Ideally, the length C should be ≤ 9 mm. Similarly, the height L of the tapered beam splitter 1 should also be as short as possible.

[0111] The advantages of this embodiment are: easy to manufacture and very low cost; the disadvantages are: the fine branch light beam 402 emitted from the light outlet of the guide tube 301 has a large divergence angle and will disperse if it is projected not far away. The diameter of the light spot projected from the light outlet 102 with a diameter of 1mm at a distance of 35mm will be greater than 20mm. In other words, the focal length of this condenser 9 is very small, which will result in a large area of ​​the light receiving area 303.

[0112] Example 2.

[0113] A thinner rectangular solar fixed-focus concentrator 9 is produced.

[0114] As shown in Figures 12 and 13, the beam splitter tube 1 and the guide tube 301 are combined into a straight light guide tube 11. The straight light guide tube 11 is constructed from an optical fiber (tube) with a core diameter (i.e., light inlet diameter D) ≤ 1.5 mm and a height (L) ≤ 5 mm. For example, 10,624 quartz optical fibers with a core diameter d of 1 mm (preferably 0.25-1.5 mm) and a length L of 3 mm are used as the beam splitter tube 1 and the guide tube 301. These are arranged (bonded) to form a honeycomb-shaped (fiber array) beam splitter 2 measuring 128 mm × 83 mm × 3 mm, with flattened or polished top and bottom ends.

[0115] At the lower end of the honeycomb-shaped beam splitter 2, a Fresnel lens 12 covered with microlenses 103 is installed. The Fresnel lens 12 is a 128mm×83mm×2mm focusing lens made of optical-grade PC material; the diameter of the microlenses 103 is approximately 5mm. In this way, the beam splitter 1 and the guide tube 301 are combined into a mutually parallel (millimeter-level perpendicular to the guide mirror) straight light guide tube 11. When sunlight 4 from all directions enters from the upper end of the numerous optical fibers (i.e., the straight light guide tube 11) in the honeycomb-shaped beam splitter 2, which has many shallow pits 13 on its surface, it is like being combed (i.e., manipulated or simulated) into roughly parallel beams, which then enter the Fresnel lens 12, whose surface is covered with microlenses 103, perpendicularly, thereby facilitating the focusing of the Fresnel lens 12. In other words, the n guide tubes 301 are all perpendicular to the Fresnel lens 12, so that the n fine branch light beams 402 are uniformly simulated into quasi-parallel light beams 403, vertically incident on the micro lens 103 layer for convergence shaping (i.e., refraction transformation), and then focused on the light receiving area 303 by the Fresnel lens 12.

[0116] The ingenious and innovative design involves sunlight 4 entering from all directions through the upper ends of the numerous optical fibers within the honeycomb-shaped beam splitter 2, which has numerous shallow pits 13 on its surface. The fibers then transform the sunlight into roughly parallel, branched beams 402, which then enter the Fresnel lens 12, whose surface is covered with microlenses 103. Like parallel light, the Fresnel lens 12 focuses the light onto the light-receiving area 303, forming a fixed focal point. Because this focal point does not move with the sun's movement, this embodiment eliminates the need for high-precision supports and complex sun-tracking systems. The system offers low-cost, stable, and reliable solar concentrating capabilities, enabling high-efficiency solar energy collection.

[0117] In this way, the cost performance of the solar fixed-focus concentrator 9 can be greatly improved.

[0118] The advantages of this embodiment are: the solar fixed-focus concentrator 9 is light and thin; in this example, the diameter of one microlens 103 is much larger than the diameter of one light-guiding straight tube 11, and only multiple light-guiding straight tubes 11 can share one microlens 103. Therefore, its disadvantage is: the fine light beam 402 emitted from the guide tube 301 into the Fresnel lens 12 has a large divergence angle, which will cause the area of ​​the light-receiving area 303 to be larger and the light capture rate to be lower.

[0119] Example 3.

[0120] A bent straight tube solar fixed-focus concentrator 9 is manufactured with reference to the above-mentioned embodiments 1 and 2 and FIG. 11 .

[0121] A 128mm×83mm×16mm bent straight tube array spectroscope 2 is manufactured using optical-grade PC (polycarbonate) or aluminum, as shown in FIG11 , and is used to split the received (large-area) incident sunlight 4 into n thin beams. For example, n bent straight tubes (type spectroscopes 1) with a light inlet 102 having an aperture D of 0.8mm and a height L of 15mm are arranged and combined to form a spectroscope 2, where n is equal to 1220. The light inlets 102 of the bent straight tubes all face the upper end of the spectroscope 2 to receive sunlight 4; the lower sections of the 1220 bent straight tubes are inclined guide tubes 301, and the guide openings 307 of the guide tubes 301 all face downwardly at an angle toward the light receiving area 303. In other words, the beam splitter 1 is a thin tube with a vertical upper section and an inclined lower section; the light receiving area 303 is arranged about 150 mm below the center of the beam splitter 2; the sunlight 4 enters from the light entrance 102, and after several turns, is emitted from the guide port 307; the n thin branch light beams 402 emitted from the guide port 307 (like n miniature spotlight beams) are all emitted to the light receiving area 303 at the same fixed position, thereby forming a fixed-focus concentrated light.

[0122] The advantages of this embodiment are: easy to manufacture and very low cost; the disadvantages are: the fine light beam 402 emitted from the guide tube 301 has a large divergence angle and will disperse if it is not projected far (in other words, the focal length of the condenser 9 is very small), which will cause the area of ​​the light receiving area 303 to be larger and the focusing degree to be low.

[0123] Example 4.

[0124] Another solar fixed-focus concentrator 9 is produced and manufactured.

[0125] In the above-mentioned embodiment 1, the branched light beam 402 is directly emitted from the light outlet of the guide tube 301, with a large divergence angle, severe scattering, difficulty in precise focusing, and a relatively low light capture rate. Therefore, the following technical improvement measures are adopted in this embodiment.

[0126] As shown in Figures 3 and 4 , a set of micro-convex lenses, as shown in Figure 5 , is positioned in front of the light outlet (i.e., guide opening 307) of each guide tube 301, or in front of the tip 101 of each beam splitter 1, serving as a flattening mirror 10. In other words, the light outlet (i.e., guide opening 307) of the guide tube 301 is oriented in the specific direction (i.e., the direction 17 of the line connecting the center of the guide opening 307 and the center of the flattening mirror 10). This ensures that each guide opening 307 is at the focal position (i.e., the predetermined projection point) on the focal plane 308 of the micro-convex lens. This serves to further refract the branched light beams 402 and their scattered light 401 into quasi-parallel beams 403 (with extremely small divergence angles), which are then directed toward the light receiving area 303 as quasi-parallel beams 403, thereby forming a fixed-focus focused beam. In other words, the branched light beams 402 and their scattered light 401 emitted from the plurality of guide openings 307 are converged and shaped (i.e., refracted) by the flattening mirror 10 into quasi-parallel light beams 403, which are then emitted through the air toward the light receiving area 303. It is preferable to ensure that the axes 304 of the plurality of flattening mirrors 10 each pass through the same center point or line of the light receiving area 303.

[0127] As shown in FIG7 , a group of concave mirrors as shown in FIG6 are provided in front of the light outlet (i.e., the guide outlet 307) of each guide tube 301 as a flattening mirror 10 to ensure that each of the guide outlets 307 is located at the focal position (i.e., the predetermined projection point) on the focal plane 308 of the concave mirror; and are used to further reflect and converge the fine branch light beam 402 and its scattered light 401 into a quasi-parallel light beam 403 (with an extremely small divergence angle), and respectively project them toward the light receiving area 303 in the form of the quasi-parallel light beam 403, thereby forming a fixed-focus light.

[0128] As shown in FIG25 , a micro-reflector 7 (e.g., a conical or spherical surface) is preferably provided immediately in front of the guide opening 307 and adjacent to the guide opening 307. This is used to deflect the branched light beam 402 toward the concave surface of the concave mirror (i.e., the inner wall of the parabola), where it is converged and shaped (i.e., reflected and transformed) into a quasi-parallel light beam 403, which is then directed toward the light receiving area 303. This prevents some light directly in front of the guide opening 307 from being directly emitted and dispersed without being converged and shaped by the concave surface. In other words, the micro-reflector 7 (e.g., a conical or spherical surface) is provided in front of the guide opening 307 to block light directly emitted forward from the focal point light source 306 and reflect it toward the concave mirror, thereby further concentrating the generated quasi-parallel light beam 403. Research has shown that the optimal distance between the micro-reflector 7 and the guide opening 307 is ≤ five times the diameter d of the guide opening 307.

[0129] 8 , 9 and 10 , a reflective cup as shown in FIG. 8 is provided in front of the light outlet (i.e., the guide outlet 307) of each guide tube 301 as a flattening mirror 10 to ensure that each guide outlet 307 is located at a (non-focal) position (predetermined projection point) on the focal plane 308 of the flattening mirror 10. When the direction of the guide outlet 307 remains unchanged, the angle between the axis 304 of the flattening mirror 10 in the left half of the solar fixed-focus concentrator 9 shown in FIG. 10 and the horizontal line 305 decreases one by one from left to right (i.e., from the edge to the center), and the angle between the axis 304 of the flattening mirror 10 in the right half of the solar fixed-focus concentrator 9 shown in FIG. 10 and the horizontal line 305 increases one by one from left to right (i.e., from the center to the edge).

[0130] Alternatively, when the angle between the axis 304 of the flattening mirror 10 and the horizontal line 305 remains unchanged, the angle α between the axis 304 of the guide tube 301 and its guide port 307 in the left half of the solar fixed-focus concentrator 9 shown in Figure 10 and the horizontal line 305 is ensured to increase one by one from left to right (i.e., from the edge to the center) (as shown in Figure 20), and the angle α between the axis 304 of the guide tube 301 and its guide port 307 in the right half of the solar fixed-focus concentrator 9 shown in Figure 10 and the horizontal line 305 is ensured to decrease one by one from left to right (i.e., from the center to the edge).

[0131] Of course, the direction of the guide opening 307 and the angle between the axis 304 of the flattening mirror 10 and the horizontal line 305 can also be varied together (as shown in FIG21 ), so that when a thin branched light beam 402 with a very small divergence angle (i.e., high straightness) emitted from the guide opening 307 is obliquely incident on the flattening mirror 10, the flattening mirror 10 can reflect and converge it into a quasi-parallel light beam 403 (with an extremely small divergence angle), which then obliquely enters the light receiving area 303 in the form of the quasi-parallel light beam 403. Comparisons and measurements show that the solar fixed-focus concentrator 9 shown in FIG10 is the technical solution with the lowest cost, lowest light loss rate, and highest light capture rate among the many embodiments of the present invention, that is, the most cost-effective technical solution.

[0132] Preferably, the angle between the line connecting the guide port 307 and the center of the flattening mirror 10 and the axis 304 of the flattening mirror 10 is an acute angle, so that the quasi-parallel light beam 403 reflected from the flattening mirror 10 avoids the guide tube 301 and is emitted to the light receiving area 303, thereby preventing the guide tube 301 from blocking the quasi-parallel light beam 403 and causing light loss.

[0133] It is desirable to set the guide port 307 or the pointed tip 101 at the focal position of the flattening mirror 10, and treat the light emitted by the guide port 307 or the pointed tip 101 as the scattered light 401 emitted by the point light source 306 at the focal plane 308 or the focal position, and convert it into a quasi-parallel light beam 403 (with an extremely small divergence angle) through the flattening mirror 10.

[0134] To simplify the process and facilitate manufacturing, as shown in FIG3 , the length C of the guide tube 301 can be shortened, even to near zero, if necessary, so that the opening of the nozzle 101 and the guide opening 307 become one. This allows the light direction to be adjusted not entirely by the guide tube 301, but by the guide mirror (e.g., the Fresnel lens 12) to further adjust the direction, so that the branched light beam 402 (emitted from the nozzle 101) is refracted and redirected by the guide mirror and (indirectly) incident on the light receiving area 303, thereby achieving focusing.

[0135] Preferably, as shown in FIG4 , instead of relying on the guide mirror (e.g., Fresnel lens 12) to adjust the direction, the guide tube 301 can be connected to the astigmatism cavity, and the axis 304 of the flattening mirror 10 can be aligned with the light receiving area 303, so that the quasi-parallel light beam 403 directly hits the light receiving area 303. In other words, the axis 304 of the flattening mirror 10 passes through (or points to) the center point or line of the light receiving area 303.

[0136] In order to maximize the parallelism of the quasi-parallel light beam 403 and reduce the manufacturing difficulty, the size of the flattening mirror 10 should be appropriately enlarged, but not too large. It is best that the diameter of a single flattening mirror 10 is ≤ the diameter of the light inlet 102 of a single conical beam splitter 1.

[0137] In order to simplify the process and facilitate manufacturing, the direction of the light can be adjusted not entirely by the guide tube 301, but also by relying on a guide mirror such as a guide reflector 7 to adjust the direction of the quasi-parallel light beam 403; in other words, the quasi-parallel light beam 403 can also be indirectly directed to the light receiving area 303 by adjusting the direction through a reflector 7 (as shown in FIG. 5 ) or a guide mirror (such as the Fresnel lens 12 shown in FIG. 3 ).

[0138] To prevent interference between two adjacent flattening mirrors 10, as shown in FIG22 , the direction of the guide opening 307, the angle between the axis 304 of the flattening mirror 10 and the horizontal line 305, and the height of the flattening mirror 10 are adjusted together. This allows the flattening mirror 10 to reflect and converge a narrow branch light beam 402 with a very small divergence angle emitted from the guide opening 307, forming a quasi-parallel light beam 403 (with a very small divergence angle) when it is obliquely incident on the flattening mirror 10. This beam then obliquely enters the light receiving area 303. In other words, the distances from the flattening mirror 10 and the guide opening 307 to the beam splitter 2 are successively shortened from the outside to the inside.

[0139] In this way, the quasi-parallel light beam 403 will always remain parallel and its direction will not change, and will not change with the movement of the sun, thereby eliminating the need for high-precision support and complex sun tracking systems.

[0140] Because the n guide openings 307 in this embodiment are far away from the light receiving area 303, the high temperature of the light receiving area 303 will not burn the guide tube 301 and its guide opening 307. In addition, because the n quasi-parallel light beams 403 in this embodiment are emitted to the light receiving area 303 through space, all of them are precisely converged at the same position (point or line), so the concentration can be very high, which can reach nD 2 / d 2 (can reach 1000) times or more. Precisely because of such a concentration of up to a thousand times, the fixed-focus concentrator of the present invention can be applied to the fields of concentrated photovoltaics (CPV) and solar thermal power generation. Solar thermal power generation is an important direction for the utilization of new energy, and its main forms are trough, tower, and dish (disc) systems. The biggest advantage of solar thermal power generation is that the power output is stable, and it can be used as basic power and for peak regulation; in addition, its mature and reliable energy storage (heat storage) configuration can continuously generate electricity at night. The fixed-focus concentrator technology described in the present invention is expected to open up the fourth type of solar thermal power generation system after the current trough, tower, and dish (disc) types - the fixed-focus concentrating power generation system.

[0141] The advantages of this embodiment are: the quasi-parallel light beam 403 formed by the flattening process (i.e., convergence shaping) has an extremely small divergence angle and will not disperse even if projected very far. In other words, the focal length of the condenser 9 can be very long (for example, it can be as long as tens of centimeters or even hundreds of centimeters), the concentration can be very high, and the light capture rate is high; the disadvantages are: the manufacturing process is relatively complicated and the processing precision requirements are high.

[0142] Example 5.

[0143] With reference to the above-mentioned embodiments 1 and 4, a conical beam splitter type solar fixed-focus concentrator 9 is manufactured.

[0144] As shown in Figure 14 , a honeycomb-shaped (light cone array) beam splitter 2 (see Figure 15 ), measuring 128 mm × 83 mm × 16 mm, is fabricated from optical-grade PC (polycarbonate). For example, 122 conical beam splitters 1 are arranged to form a honeycomb-shaped beam splitter 2. The trumpet-shaped light inlets 102 of each conical beam splitter 1 face the upper end of the honeycomb-shaped beam splitter 2, receiving sunlight 4 and compressing (splitting) the received (large-area) incident sunlight 4 into 122 light beams. The tips 101 of each conical beam splitter 1 face the lower end of the honeycomb-shaped beam splitter 2. The diameter D of each trumpet-shaped light inlet 102 is set to less than 8 mm, the diameter of each tip 101 is set to 1 mm, and the height L of each conical beam splitter 1 is set to less than 16 mm. The tips 101 are extended to form vertically downward-facing guide tubes 301, which emit narrow beams 402.

[0145] At the lower end of the honeycomb beam splitter 2, the microlens 103 layer shown in Figure 13 is omitted, and a 128mm x 83mm x 1.5mm Fresnel lens 12 made of optical-grade PC is directly bonded. This allows sunlight 4 from all directions, entering through the horn-shaped light inlet 102 of the honeycomb beam splitter 2, to be shaped by the guide tube 301 into narrow, roughly parallel beams 402 perpendicular to the Fresnel lens 12, each with a very small divergence angle (i.e., high straightness), thus facilitating focusing by the Fresnel lens 12.

[0146] The ingenious and innovative design involves sunlight 4 entering the honeycomb beam splitter 2 from all directions, which is then shaped by the guide tube 301 into approximately parallel, narrow beams 402 with a small divergence angle (i.e., high straightness). These beams then enter the Fresnel lens 12, where they are focused onto the light receiving area 303 like parallel light, forming a fixed focal point. Because this focal point does not move with the sun's movement, this embodiment eliminates the need for high-precision supports and complex sun-tracking systems, resulting in low-cost, stable, and reliable solar concentrating systems that can achieve high solar power efficiency.

[0147] Compared with the second embodiment, the present embodiment does not have a micro-lens 103 layer, which has the disadvantage that the branched light beam 402 entering the Fresnel lens 12 from the guide tube 301 has a large divergence angle and is not projected far, which results in a larger area of ​​the light receiving area 303, a lower light capture rate, and a lower light concentration.

[0148] Example 6.

[0149] A solar fixed-focus concentrating photovoltaic power generation device is manufactured.

[0150] As shown in FIG16 , a rectangular solar fixed-focus concentrator 9 manufactured in Example 1 is used, and a concentrating photovoltaic panel 6 is mounted in the light receiving area 303 to receive sunlight 4 concentrated by the solar fixed-focus concentrator 9 to generate electricity. To increase the sunlight reception angle, it is preferable to add a miniature transparent light shield or a miniature (convex) lens 103 to each of the light inlets 101.

[0151] Research has found that the guide opening 307 and the flattening mirror 10 are easily covered with dust due to long-term outdoor use, which can easily lead to severe reflected light loss. It is desirable to enclose the guide opening 307, the flattening mirror 10, and the photovoltaic panel 6 with a dustproof housing 16, and to install a heat sink 601 on the photovoltaic panel 6 to dissipate heat outside the dustproof housing 16.

[0152] Example 7.

[0153] A solar fixed-focus concentrating heat collecting device is manufactured.

[0154] As shown in FIG17 , a rectangular solar fixed-focus concentrator 9 manufactured in Example 1 is used, and a heat collection device such as a solar heat collecting tube 14 is installed at the position of the light receiving area 303 to receive heat generated by the sunlight 4 concentrated by the solar fixed-focus concentrator 9. The heat collection device can be a solar heat collecting tube, a solar cooker, a solar water heater, or other solar heat collection device.

[0155] Embodiment 8.

[0156] It is desirable that, referring to the above-mentioned multiple embodiments, as shown in Figure 26, the splitter tube 1, the guide tube 301 or the tip 101, the (concave mirror type) flattening mirror 10, the guide port 307 or the tip 101 port at the focus, the reflector 7 and other multiple components are designed to be combined together into a splitter and flattening module as a whole 15 that can output a quasi-parallel light beam 403, so as to facilitate one-time processing and molding by molding processes such as injection molding and hot pressing.

[0157] As best shown in FIG27 , the micro-mirror 7 is secured to the guide tube 301 using a fastener 701, such as a transparent nut. Alternatively, the micro-mirror 7 can be secured to the guide tube 301 using other fastening methods, such as plugging, snapping, or bonding. This allows the height of the micro-mirror 7 to be fine-tuned by rotating the transparent nut, ensuring that it is precisely positioned at the focal point of the (concave mirror-type) flattening mirror 10.

[0158] In this way, the overall beam splitting and flattening module 15 is used in conjunction with a guide mirror such as a Fresnel lens 12 (see Figures 3 and 5 ), thereby forming the solar fixed-focus concentrator 9 of the present invention. Because the guide opening 307 or the tip 101 is at the focal point (i.e., the predetermined projection point), regardless of how the incident angle of sunlight 4 changes, the overall beam splitting and flattening module 15 will convert it into the quasi-parallel beam 403 with a constant output direction. Therefore, this embodiment does not require high-precision supports and complex sun tracking systems, and the concentrating cost is low, stable and reliable, and can concentrate solar energy at a high magnification.

[0159] Research has shown that the light outlet of the guide tube 301 and the flattening mirror 10 must be at least 0.3√nD (i.e., zero point triple square root of nD) away from the light receiving area 303 (preferably at least 41.5 mm). This prevents the high temperature of the light receiving area 303 from damaging the light outlet of the guide tube 301 and the flattening mirror 10, facilitating processing and manufacturing. It also facilitates total internal reflection of the flattening mirror 10, thereby reducing light loss, improving light concentration, and achieving high-magnification light focusing. In other words, simply extending the light outlet of the guide tube 301 directly to the light receiving area 303 will only result in low-magnification light focusing, making it difficult to improve the photoelectric conversion efficiency. Furthermore, the light outlet of the guide tube 301 and the flattening mirror 10 are extremely susceptible to aging and damage.

[0160] The guide mirror described in the present invention includes a lens, a concave mirror, a reflector, etc., which can be used to change the emission direction of a thin light beam; the flattening mirror described in the present invention includes a concave mirror, a lens, etc., which can convert scattered light from a point light source at a focal position into parallel light; the concave mirror described in the present invention is commonly known as a reflective cup, a reflective bowl, a reflector, a focusing cup, a focusing bowl, etc.

[0161] The above disclosure is only a preferred embodiment of the present invention. The drawings are only schematic diagrams of principles, not construction drawings. The size ratios between the various components are not necessarily coordinated and reasonable. Therefore, they cannot be used to limit the scope of rights of the present invention. Equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A solar fixed-focus concentrator, characterized in that: ① n beam splitters are arranged and combined into a beam splitter array module - a beam splitter, which is used to split the incident sunlight in a large range received at its upper end into many thin beams, where n ≥ 5 or 25 or 50 or 100 or 500 or 1000 or 5000; ② The beam splitter is provided with a guide tube, the inlet end of the guide tube is connected to the beam splitter, and the outlet end of the guide tube extends to a predetermined projection point and faces a specific direction; the light outlet of the guide tube, the guide port, is used to adjust the emission direction of the thin light beam; ③ The thin branch light beam is injected into the guide tube from the lower end of the beam splitter, and then propagates from the guide tube to the predetermined projection point and is emitted from the guide port; ④ The thin light beams emitted from the plurality of predetermined projection points and their guide ports are respectively directed to a target light receiving area of ​​a smaller range at the same fixed position through space, thereby forming a fixed-focus spotlight; ⑤ The diameter of the light entrance of the beam splitter is D, and the diameter of the light exit of the guide tube is d, wherein D / d≥25 or 10 or 5 or 3.7 or 1.7 or 1; ⑥ The beam splitter and the guide tube are both optical channels with high reflectivity and / or total reflection characteristics.

2. The solar fixed-focus concentrator according to claim 1, characterized in that: The guide tubes are straight tubes parallel to each other, and their guide openings are all directed toward a Fresnel lens-type guide mirror whose surface is covered with micro lenses, so as to further converge and shape the thin light beams, and arrange them into roughly parallel flattened light beams to be injected into the guide mirror; after the guide mirror refracts and deflects the flattened light beams, they are all focused on the light receiving area.

3. The solar fixed-focus concentrator according to claim 1, characterized in that: The beam splitter is a conical beam splitter with a taper D / L≤0.75 or 0.35 or 0.25 or 0.10, and is used to split, fold and shrink the incident sunlight received at its upper end into the thin branch light beam with high energy flux density.

4. The solar fixed-focus concentrator according to claim 3, characterized in that: A flattening mirror is provided in front of each guide port or the tip of each conical beam splitter; the flattening mirror is used to further converge and shape the thin branch light beam and its scattered light incident thereon into a quasi-parallel light beam, and emit it to the light receiving area in the form of the quasi-parallel light beam.

5. The solar fixed-focus concentrator according to claim 1, 2, 3 or 4, characterized in that: It includes any one or more combined technical measures from ① to ⑩ below: ① The guide tube is a light channel with a diameter d of 0.1-5 mm or / and the light entrance end of the beam splitter is a honeycomb polygon; ② The light inlet of the beam splitter is a shallow pit light inlet or a convex lens light inlet; or, the upper surface of the beam splitter is provided with many shallow pits or convex light-collecting covers; or, the upper end of the beam splitter is provided with an anti-reflection transparent protective layer; ③ The predetermined projection point is a point on the focal plane of the flattening mirror, or / and the specific direction is the direction of a line from the center point of the guide port to the center point of the flattening mirror; ④ A diffuser is provided near the beam splitter; or a reflector is provided near the beam splitter; ⑤ The diameter of a single flattening mirror is ≤ the diameter of the light entrance of a single conical beam splitter; ⑥ The angle between the axis of the flattening mirror and the horizontal line decreases successively; or, the angle α between the direction of the guide port and the horizontal line increases successively; or, the distance from the flattening mirror and the guide port to the beam splitter decreases successively; ⑦ A micro-reflector is arranged in front of the guide port, which is used to turn the thin branch light beam to the concave surface of the concave mirror, and then reflect it into a quasi-parallel light beam by the concave surface and then emit it to the light receiving area; ⑧ The beam splitter, the guide tube or the pointed nozzle, the flattening mirror, and the guide port or the pointed nozzle on the focal plane together constitute a beam splitting and flattening module capable of outputting a quasi-parallel beam; ⑨The beam splitter is a wedge-cone beam splitter; ⑩ The light outlet of the guide tube and the flattening mirror are at least 0.3√nD away from the light receiving area.

6. The solar fixed-focus concentrator according to claim 5, characterized in that: It includes any one or more of the following combined technical measures: ① The axes of the plurality of flattening mirrors respectively pass through the same light receiving area; ② The angle between the line connecting the center point of the guide port to the center point of the flattening mirror and the axis of the flattening mirror is an acute angle, so that the quasi-parallel light beam reflected from the flattening mirror avoids the guide tube and is directed to the light receiving area; ③ The distance from the flattening mirror to the guide opening or the pointed mouth opening is ≤32.2mm; ④ The plurality of thin light beams are bundled into one beam, and emitted from the same guide port to the same flattening mirror in the form of the same point light source; ⑤ The branched light beams and scattered light emitted from the plurality of guide ports are adjusted into quasi-parallel light beams by the flattening mirror and then emitted toward the light receiving area through the air.

7. A solar fixed-focus concentrating photovoltaic power generation device, characterized in that: Use any one of the solar fixed-focus concentrators in claims 1-6; photovoltaic panels are installed in the light-receiving area and receive the sunlight concentrated by the solar fixed-focus concentrator to generate electricity.

8. The solar fixed-focus concentrating photovoltaic power generation device according to claim 7, characterized in that: The guide port, the flattening mirror and the photovoltaic cell panel are enclosed in a dustproof housing; a heat sink capable of dissipating heat to the outside of the dustproof housing is installed on the photovoltaic cell panel.

9. A solar fixed-focus concentrating heat collecting device, characterized in that: Use any one of the solar fixed-focus concentrators in claims 1-6; a solar thermal collector is installed in the light-receiving area and receives heat generated by the sunlight concentrated by the solar fixed-focus concentrator.

10. The solar fixed-focus concentrating heat collector device according to claim 9, characterized in that: The guide port, the flattening mirror and a local area of ​​the solar thermal collector are enclosed in a dustproof housing.

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