CN109842367B - Sunlight collecting optical device and system and light collecting method of system - Google Patents
Sunlight collecting optical device and system and light collecting method of system Download PDFInfo
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- CN109842367B CN109842367B CN201910167037.6A CN201910167037A CN109842367B CN 109842367 B CN109842367 B CN 109842367B CN 201910167037 A CN201910167037 A CN 201910167037A CN 109842367 B CN109842367 B CN 109842367B
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The invention belongs to the technical field of solar energy collection, and particularly relates to a sunlight collecting optical device and system and a light collecting method of the system. The sunlight collecting optical device comprises a main reflecting mirror and a secondary optical element; the main reflector and the secondary optical element are rotationally symmetrical bodies and have a common rotational symmetry axis; the secondary optical element is arranged in a light focusing area of the main reflector and is fixed relative to the space position of the main reflector; the ratio of the top end diameter of the secondary optical element to the upper end diameter of the primary mirror is less than 0.15. The ratio is favorable for designing an optical structure with high light concentration ratio, a small secondary optical element and shielding of the secondary optical element on light rays.
Description
Technical Field
The invention belongs to the technical field of solar energy collection, and particularly relates to a sunlight collecting optical device and system and a light collecting method of the system.
Background
The high-concentration photovoltaic technology is to use a large-area collecting mirror to collect light energy on a solar cell with a small area, and is usually a multi-junction III-V compound semiconductor solar cell. Known concentrating photovoltaic systems mainly have the following technologies:
(1) The Fresnel lens is used for refracting and converging sunlight on the secondary optical element below, the secondary optical element plays roles of light guiding, light homogenizing and angle tolerance improvement, and the sunlight reaches the solar cell below to be received after passing through the secondary optical element.
(2) The solar light is reflected and converged on the secondary optical element and the solar cell above by the parabolic reflector, and the receiving component in the mode is positioned right above the system, so that the solar light is blocked and is not easy to fix and package.
(3) The secondary reflection optical structure is utilized to turn the concentrated light to the lower part for receiving, for example, the Cassegrain reflection structure is utilized to concentrate the light, the sunlight is reflected and concentrated by the main reflector to the secondary reflector, and then the secondary reflector is reflected and turned to be concentrated on the secondary optical element and the solar cell sheet below, the receiving part in the mode is positioned under the system, so that the fixation and the heat dissipation are convenient, but the system is additionally provided with a secondary reflector, and the secondary reflector is often adhered on a glass baffle plate or supported by a bracket, so that the problems of positioning and fixation exist.
(4) The eccentric reflector is utilized to reflect sunlight to the upper side, and the receiving part is arranged above the side wall of the system, so that the problems of fixing the reflector, packaging the system module and the like exist.
Compared with the transmission type concentrating photovoltaic technology using a Fresnel lens, the reflection type concentrating photovoltaic technology is proposed by a person skilled in the art, the reflection type concentrating photovoltaic system uses the reflecting mirror to concentrate light, the reflecting mirror can be made of glass or metal, the yellowing and embrittlement problems caused by using plastics are avoided, and the service life of the system can be effectively prolonged. In the concentrated photovoltaic technology (3) of the Cassegrain reflecting structure, the secondary reflecting structure can be utilized to turn and collect the light energy to the receiving part below, so that the packaging and heat dissipation are facilitated, but the current structure basically utilizes independent secondary reflecting mirrors to reflect the turned light energy, independent secondary optical elements guide the light to the battery piece, and the secondary reflecting mirrors are positioned above the secondary optical elements and need to be fixed by attaching additional parts.
In the prior art, the method for fixing the secondary reflector comprises the following steps: 1) The secondary reflector is adhered below the glass cover plate or supported by a bracket from the periphery, and a receiving component formed by the secondary optical element and the battery piece is positioned below the secondary reflector; 2) The secondary reflector is fixed at the top end of the central metal bracket, and reflected light energy is received by battery pieces arranged around the bottom of the bracket. In method 1), there are problems of sub-mirror positioning and fixing, and the sub-mirror tends to be large in size. In the method 2), the secondary reflector is supported by the central metal bracket, so that a conventional receiving mode of centering the battery piece cannot be realized, the size of the solar battery piece used in the high-power concentrating system is generally smaller, and the common size is 5mm multiplied by 5mm or 10mm multiplied by 10mm, and the central metal bracket occupies the space in which the battery piece can be placed in the middle, so that larger area of receiving batteries are required to be arranged around, and high-power concentrating is not facilitated.
Disclosure of Invention
In order to solve the problems, the invention provides a sunlight collecting optical device, a sunlight collecting system and a light collecting method of the sunlight collecting optical device. The secondary optical element in the sunlight collecting optical device has the functions of reflecting and steering and guiding light downwards, the ratio of the top end caliber to the upper end caliber of the main reflector is smaller than 0.15, and the small secondary optical element is used for helping to design an optical structure with simple structure and high light concentration ratio.
The invention is realized by the following technical scheme:
a sunlight collecting optical device comprising a primary mirror and a secondary optical element;
the main reflector and the secondary optical element are rotationally symmetrical bodies and have a common rotational symmetry axis;
The secondary optical element is arranged in a light focusing area of the main reflector and fixed relative to the middle position of the main reflector;
the ratio of the top end caliber of the secondary optical element to the upper end caliber of the main reflector is less than 0.15.
Further, the ratio of the top end diameter of the secondary optical element to the upper end diameter of the primary mirror is less than 0.12.
Further, the secondary optical element material is a solid transparent material and comprises a turning part and a light guide part;
the steering part is connected with the light guide part up and down or is a whole;
the light guide part comprises side walls and an emergent surface at the bottom, wherein the side walls are used for guiding light;
the turning part comprises an incident surface and a secondary reflecting surface;
the incident surface is a side surface of the turning part and faces the main reflector (the light gathering direction) to receive the light reflected and gathered by the main reflector;
the secondary reflecting surface is the top surface of the steering part, and the bottom end of the secondary reflecting surface is jointed or similar to the rotation symmetry axis.
Further, the size of the incident surface covers the range of converging light rays reflected by the main reflector within the alignment tolerance range;
The secondary reflecting surface has a size just or greater than the range of travel of the incident light within the alignment tolerance.
The alignment tolerance range refers to a range of alignment tolerances permitted by the solar collection optics.
Further, the height of the turning part is not more than 50mm, and the length of the light guiding part ranges from 0 to 100mm and does not include 0mm.
Further, the distance between the intersection part (including the intersection point) of the top end of the secondary reflection surface and the uppermost refractive ray and the incident surface is a, and the range of a is 0.3mm < a <5mm, so that the size of the secondary optical element can be as small as possible, and the die pressing processing is convenient.
Further, the structures of the primary mirror and the secondary optical element are each replaced with a revolution body formed by rotation of the respective primary cross-sectional profiles about a central axis.
Further, the primary mirror includes n mirror units of the same structure, and the secondary optical element includes n optical element units of the same structure;
The n reflecting mirror units with the same structure are rotationally spliced around the central shaft to form a rotationally symmetrical body, and the n optical element units with the same structure are rotationally spliced around the central shaft to form a rotationally symmetrical body;
the rotation angle of the rotation symmetrical body is 360 degrees/n, wherein n is a positive integer, and n is more than or equal to 2.
Further, the light guide part is a cylinder, an inverted truncated cone and a prism, and the number of the side faces of the prism is at least 4.
Further, the steering part is vertically jointed with the light guide part, the main reflector comprises n reflector units with the same structure, and the steering part comprises n steering units with the same structure;
the n reflecting mirror units with the same structure are rotationally spliced around the central shaft to form a rotationally symmetrical body, and the n steering units with the same structure are rotationally spliced around the central shaft to form a rotationally symmetrical body;
The rotation angle of the rotation symmetrical body is 360 degrees/n, wherein n is a positive integer, and n is more than or equal to 2;
The light guide part is a prism, the number of the side surfaces of the prism is at least 4, the upper surface of the prism is just equal to or larger than the bottom surface of the steering part, and the lower surface of the prism is an emergent surface.
Further, the steering part is vertically jointed with the light guide part, and the main reflector and the steering part are both revolution bodies formed by rotating around a central shaft;
The light guide part is a prism, the number of the side faces of the prism is at least 4, the upper surface is just equal to or larger than the bottom face of the steering part, and the lower surface is an emergent face.
Further, when the light guide part is a prism, the number of the side faces of the prism is at least 4, the prism is easy to be compatible with the photovoltaic cell, that is, the standard commercial photovoltaic cell is mostly square, and the emergent face of the secondary optical element of the rotary structure is circular; the size of the upper surface of the light guide part is equal to or slightly larger than the size of the bottom surface of the steering part, the light guide part is connected with the bottom surface of the steering part, and the lower surface of the light guide part is matched with the size of the photovoltaic cell;
the main cross section refers to any cross section through the rotation center axis of the solar light collecting optical device of the rotary structure.
The main cross section refers to a cross section passing through symmetry axes of each portion of the solar light collecting optical device having a rotationally symmetrical structure of n (n.gtoreq.2) portions.
Further, the secondary reflecting surface is a paraboloid, an ellipsoid, a hyperboloid, or a partial paraboloid, a partial ellipsoid, a partial hyperboloid, or a free-form surface; the secondary reflection surface can lead the light rays to be uniformly distributed to the emergent surface at the bottom end of the secondary optical element after being reflected.
Further, the free-form surface includes a nearly parabolic surface, an ellipsoidal surface, and a hyperboloid.
Further, the incident surface of the secondary optical element is a plane, a curved surface or a free curved surface;
When the incident surface is a curved surface or a free curved surface, the incident angles of all parts of the converging light reflected from the main reflector can be adjusted, so that the incident angle of the edge light is not too large, and the proper curvature is beneficial to compression molding and is convenient to take and place; but also can be matched with the curvature shape of the secondary reflecting surface, thereby further reducing the caliber size of the secondary optical element.
Further, the main reflector is a paraboloid, a hyperboloid, an ellipsoid, or a partial paraboloid, a partial hyperboloid, a partial ellipsoid, or a free-form surface.
The secondary reflecting surface reflects incident light into the light guide portion so that the incident light can be totally reflected and propagated in the light guide portion.
Further, the secondary reflection surface focuses and reflects incident light to the upper end of the side wall of the light guide part, so that the incident light can be totally reflected and transmitted in the light guide part.
Further, a part of the refracted light rays entering from the incident surface can be reflected to the incident surface through the secondary reflection surface, enter the lower light guide part after being totally reflected on the incident surface, and are transmitted to the emergent surface through the total reflection of the side wall of the light guide part; the included angle alpha between the tangent line of the incident surface part irradiated by the secondary reflection surface reflection light and the horizontal direction meets theta < alpha <90 degrees, and the incident angle beta >90 degrees+theta-alpha of the incident surface irradiated by the secondary reflection surface reflection light, wherein theta is the total reflection angle of the secondary optical material.
Further, the secondary optical element makes the refracted light entering from the incident surface, and a part of the refracted light can enter the light guide part below after being reflected by the secondary reflecting surface at least twice and totally reflected by the incident surface at least once between the incident surface and the secondary reflecting surface, and is transmitted to the emergent surface through the total reflection of the side wall of the light guide part.
Further, the secondary optical element material is a transparent optical material; the transparent optical material comprises optical glass, PMMA and PC plastic.
Further, when the turning part is vertically jointed with the light guide part, the secondary optical element is formed by bonding the turning part and the light guide part.
Further, when the turning part and the light guide part are integrated, the secondary optical element is integrally pressed by adopting a precision compression molding technology.
Further, a highly reflective film is plated on the secondary reflective surface.
Another object of the present invention is to provide a solar light collecting optical system, which includes a receiving device, a mounting base plate, and a heat dissipating device; the solar energy collection optical system further comprises the sunlight collection optical device;
The receiving device is arranged below the emergent surface of the secondary optical element of the sunlight collecting optical device; the heat dissipation device is arranged at the other end of the receiving device opposite to the secondary optical element; the mounting bottom plate is arranged above the heat dissipation device and is used for placing the sunlight collecting optical device and the receiving device.
Further, the solar collection optical system further comprises a supporting heat conducting structure;
The supporting and heat conducting structure is arranged between the receiving device and the heat dissipating device.
Further, the supporting heat conducting structure is a material with high heat conductivity or a material with high heat conductivity in which a heat conducting device is arranged.
Further, the material having high thermal conductivity is copper or aluminum.
Further, the height of the supporting heat conducting structure is 50-100mm.
Further, the receiving device comprises a photoelectric conversion device and a circuit board;
The photoelectric conversion device is attached to the emergent surface of the secondary optical element in the sunlight collecting optical device, and the circuit board is arranged below the photoelectric conversion device.
Further, the photoelectric conversion device is a high-concentration solar cell.
Further, the light guiding portion may guide light to the bottom of the device to be received by the receiving device, the supporting heat conducting structure may be greatly reduced or omitted, and the light guiding portion has a light homogenizing effect.
Further, the photoelectric conversion device is replaced by an LED light emitting chip, and the sunlight collecting optical system is used as an illumination system for illumination.
Another object of the present invention is to provide a light collecting method of a solar light collecting optical system, wherein the method adopts the solar light collecting optical system, and the method directs the converging light reflected by the main reflector to the incident surface of the corresponding secondary optical element, and the converging light enters the receiving device after being refracted, reflected and totally reflected by the secondary optical element, and the receiving device converts the light energy into electric energy for subsequent use.
In the light collecting method, the converging light reflected by the main reflector is directed to the incident surface of the corresponding secondary optical element, and the focal point is approximately within the caliber of the secondary optical element, and may be located in front of the secondary reflecting surface of the secondary optical element, near the incident surface, or may be located behind the secondary reflecting surface after refraction.
It is a further object of the present invention to provide a solar collection optical system as described above for collecting solar energy by fixedly mounting the solar collection optical system on a solar tracking apparatus.
The invention has the following beneficial technical effects:
(1) The incident surface, the secondary reflection surface and the emergent surface of the secondary optical element are integrated, and the secondary optical element has the advantages of avoiding the need of external adhesion or support of a separation secondary reflector in a secondary reflection condensing structure, simplifying installation, reducing size, reducing cost and the like.
(2) The invention can integrally design the upper turning part and the lower light guide part of the secondary optical element, and can be molded into a solid element at one time, thereby further simplifying the processing and reducing the cost.
(3) The ratio of the top aperture of the secondary optical element to the upper port aperture of the main reflector is smaller than 0.15, which is helpful for designing an optical structure with high light concentration ratio, and the small secondary optical element can reduce the shielding of the secondary optical element to light.
Drawings
Fig. 1A is a schematic structural diagram of a revolution body formed by rotating a solar light collecting optical device according to embodiment 1 of the present invention around a central axis.
Fig. 1B is a schematic cross-sectional view of a sunlight collecting optical device and a light path of the sunlight collecting optical device according to embodiment 1 of the present invention.
Fig. 1C is a schematic diagram of an optical simulation path of a sunlight collecting optical device in embodiment 1 of the present invention.
Fig. 2A is a schematic diagram of a structure in which a focus of light reflected by a primary mirror is in front of a secondary reflection surface of a secondary optical element in embodiment 1 of the present invention.
Fig. 2B is a schematic diagram of a structure of the embodiment 1 of the invention in which the focus of the light reflected by the primary mirror is behind the secondary reflection surface of the secondary optical element.
Fig. 2C is a schematic cross-sectional structure and an optical path diagram of a secondary optical element in the sunlight collecting optical device according to embodiment 1 of the present invention, wherein the incident surface and the secondary reflection surface of the secondary optical element are composite free-form surfaces.
Fig. 3A is a schematic diagram of a light beam directly reflected by the secondary reflection surface of the secondary optical element into the light guiding portion in embodiment 1 of the present invention.
Fig. 3B is a schematic diagram of a light ray in embodiment 1 of the present invention, which is reflected once by the secondary reflection surface of the secondary optical element and then totally reflected by the incident surface to the light guiding portion.
Fig. 3C is a schematic view of the light beam reflected by the secondary reflection surface of the secondary optical element 2 times and totally reflected by the incident surface 1 time to the light guiding portion in embodiment 1 of the present invention.
Fig. 4 is a schematic diagram showing the positions of angles α, β and γ in the incident and reflected paths of the light rays of the secondary optical element in embodiment 1 of the present invention.
Fig. 5A and 5B show the distribution of incident light having positive and negative offset angles on the incident surface and the secondary reflection surface in the embodiment of the present invention.
Fig. 6 is a schematic structural view of a solar light collecting optical device according to embodiment 2 of the present invention, which is a rotationally symmetrical body with a fixed angle of 90 ° as a rotation angle.
Fig. 7 is a schematic structural diagram of a sunlight collecting optical device in embodiment 3 of the present invention, in which the turning part is a rotator and the light guiding part is a quadrangular prism.
Fig. 8 is a schematic view showing a structure of a sunlight collecting optical system in embodiment 5 of the present invention.
Fig. 9 is a schematic view showing the structure of a solar light collecting optical system not including a light guiding portion in embodiment 6 of the present invention.
Fig. 10 is a schematic structural diagram of the secondary optical element in embodiment 9 of the present invention, which does not include a supporting heat-conducting structure.
Reference numerals illustrate: 11 is a main reflector; 12 is a secondary optical element, 121 is a turning portion, 1211 is an incident surface, 1212 is a secondary reflecting surface, 1214 is a light guiding side wall, 122 is a light guiding portion, and 1221 is an exit surface; 21 is a photoelectric conversion device, 22 is a circuit board; 3 is a supporting heat conducting structure; 4 is an installation bottom plate; and 5 is a heat dissipation device.
Detailed Description
The present invention will be described in further detail with reference to the following examples and the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
On the contrary, the invention is intended to cover any alternatives, modifications, equivalents, and variations as may be included within the spirit and scope of the invention as defined by the appended claims. Further, in the following detailed description of the present invention, certain specific details are set forth in order to provide a better understanding of the present invention. The present invention will be fully understood by those skilled in the art without the details described herein.
Example 1
The embodiment provides a sunlight collecting optical device, the optical structure, the main section outline and the optical simulation light path of which are respectively shown in fig. 1A, 1B and 1C, wherein the sunlight collecting optical device comprises a main reflector and a secondary optical element;
the main reflector and the secondary optical element are rotationally symmetrical bodies and have a common rotational symmetry axis;
The secondary optical element is arranged in a light focusing area of the main reflector and fixed relative to the middle position of the main reflector;
the ratio of the top end caliber of the secondary optical element to the upper end caliber of the main reflector is less than 0.15.
The secondary optical element material is a solid transparent material and comprises a turning part and a light guide part;
the steering part is connected with the light guide part up and down or is a whole;
the light guide part comprises side walls and an emergent surface at the bottom, wherein the side walls are used for guiding light;
the turning part comprises an incident surface and a secondary reflecting surface;
the incident surface is a side surface of the turning part and faces the main reflector (the light gathering direction) to receive the light reflected and gathered by the main reflector;
the secondary reflecting surface is the top surface of the steering part, and the bottom end of the secondary reflecting surface is jointed or similar to the rotation symmetry axis.
The height of the turning part is not more than 50mm, and the length of the light guide part ranges from 0mm to 100mm and does not contain 0mm.
The light beams reflected and converged by each part of the main reflector are directed to the incident surface of the corresponding secondary optical element, and the focus is approximately in the caliber of the secondary optical element, and can be positioned in front of the secondary reflecting surface and near the incident surface as shown in fig. 2A, or can be positioned behind the secondary reflecting surface after being refracted as shown in fig. 2B. Because the refractive index of the optical material of the secondary optical element is larger than that of air, converging light enters the secondary optical element through the incident surface and then is refracted, the included angle between the incident light at the top end and the incident light at the bottom end is greatly reduced, and the caliber range of the advancing light is greatly smaller than the advancing range of the advancing light in the air, so that the refractive light can be reflected by using smaller secondary reflection, and the design of the secondary optical element with smaller size than the steering secondary reflection surface required by the direct propagation of the light in the air is facilitated.
The size of the incidence surface covers the range of converging light rays reflected by the main reflector within the alignment tolerance range;
The secondary reflecting surface has a size just or greater than the range of travel of the incident light within the alignment tolerance.
The alignment tolerance range refers to that the solar energy collection system cannot face the sun without deviation in the sun tracking process due to the limited tracking precision of the solar energy tracking system or the limited installation precision of the solar energy collection system, so that the common high-concentration solar energy collection system has a positive and negative deviation angle tolerance range according to the accommodation capacity of the optical design, and the larger the tolerance range is, the cheaper the tracking cost of the system is. The invention aims to design a secondary optical element with small size, so that a secondary reflection surface can exactly accommodate incident light rays within a tolerance range, and the size of the element is enlarged without adding an additional secondary reflection surface. As shown in fig. 5A and 5B, this is the distribution of incident light rays having positive and negative deviation angles in the secondary optical element.
The secondary reflecting surface is a revolution surface formed by the rotation of a secondary reflecting surface contour line in the main section contour around a central axis and is a paraboloid, an ellipsoid, a hyperboloid or a free-form surface;
When the secondary reflecting surface is a free-form surface, the profile line of the section of the secondary reflecting surface is a partial parabola, a partial elliptic curve, a partial hyperbola, a partial circular line or a composite curve formed by combining a plurality of curve parts with different curvatures;
the secondary reflecting surface reflects incident light rays into the light guide part, so that the light rays can be totally reflected and spread in the light guide part, and the light rays are uniformly distributed on the emergent surface at the bottom end of the secondary optical element.
The incident surface is a revolution surface formed by rotating an incident surface contour line in the main section contour around a central axis, and is a conical curved surface or a free curved surface;
When the incident surface is a free curved surface, the section contour line is a partial parabola, a partial elliptic curve, a partial hyperbola, a partial circular line or a composite curve formed by combining a plurality of curve parts with different curvatures.
When the incidence surface is a free curved surface, the incidence angles of all parts of the converging light reflected from the main reflector can be adjusted, so that the incidence angle of the edge light is not overlarge; the proper curvature is beneficial to compression molding and is convenient to take and place; but also can be matched with the curvature shape of the free curved surface of the secondary reflecting surface, thereby further reducing the caliber size of the secondary optical element. As shown in fig. 2C.
The main reflector is a revolution surface formed by rotating a main reflector profile in a main section profile around a central axis, and is a paraboloid, a hyperboloid, an ellipsoid or a free-form surface;
When the main reflector is a free curved surface, the section contour line of the main reflector is a partial parabola, a partial elliptic curve, a partial hyperbola or a composite curve formed by combining a plurality of curve parts with different curvatures.
The secondary optical element material is a transparent optical material; the transparent optical material comprises optical glass, PMMA and PC plastic.
When the steering part is jointed with the light guide part up and down, the secondary optical element is formed by bonding the steering part and the light guide part;
the steering part is formed by pressing by adopting a precise compression molding technology;
The light guide part is manufactured by adopting an optical cold processing technology or a precision compression molding technology.
The distance between the intersection part (containing the intersection point) of the top end of the secondary reflection surface and the uppermost refractive ray and the incident surface is a, and the range of a is 0.3mm < a <5mm, so that the size of the secondary optical element can be as small as possible, and the requirement of die pressing processing is met; as shown in fig. 2A, 2B.
And the secondary reflecting surface is plated with a high reflecting film.
Because the turning part or the whole of the secondary optical element needs to be manufactured by adopting a precise compression molding technology, the turning part with smaller size, namely the turning part with smaller caliber of the top secondary reflecting surface, is easier to manufacture. For a condensing system adopting a solar cell with fixed size, the factor for determining the size of the secondary reflecting surface is mainly the light condensing ratio, namely the caliber of the upper end of the main reflecting mirror; and the selection of alignment tolerance ranges for the system tracking. The combination of a large concentrating ratio and a small alignment tolerance range, a small concentrating ratio and a large alignment tolerance range, are common designs for concentrating solar energy systems, for example for a concentrating ratio between 800-1500 times, an alignment tolerance range between + -0.5 deg. - + -1.2 deg., a combination of 800 times concentrating ratio and + -1.2 deg., a combination of 1000 times concentrating ratio and + -1 deg., or a combination of 1500 times concentrating ratio and + -0.5 deg. alignment tolerance are all possible combination designs.
Because the refractive index of the optical material of the secondary optical element is larger than that of air, the converging light enters the secondary optical element through the incident surface and then is refracted, the included angle between the incident light at the top end and the incident light at the bottom end is greatly reduced, and the caliber range of the advancing light is greatly smaller than the advancing range of the advancing light in the air, as shown in fig. 2A and 2B, so that the refractive light can be reflected by using smaller secondary reflection, and the design of the secondary optical element with the size smaller than that of the secondary reflection surface required by the direct propagation of the light in the air is facilitated.
The aperture size of the secondary optical element is also affected by factors such as the thickness between the secondary reflecting surface and the incident surface, and the curvature of the secondary reflecting surface. The thickness between the secondary reflecting surface and the incident surface can be measured by the distance a from the incident surface at the intersection of the top end of the secondary reflecting surface and the uppermost Fang Rushe rays, as shown in fig. 2A and 2B, the uppermost incident rays refer to the uppermost position rays reached within the allowable alignment tolerance range of the sunlight collecting optical device, the thickness is controlled to be 0.3mm-5mm, the minimum distance is dependent on the minimum size requirement which can be met by the hot pressing process, and the distance is generally controlled to be not more than 5mm due to the design requirement of high-power condensation.
The curvature of the secondary reflecting surface is different, and the optical path design is also different, so that the sizes of the elements are different. As shown in the optical path in the sectional view of fig. 3A, the secondary reflection surface of the secondary optical element directly reflects the incident light into the light guiding portion, so that the curvature of the secondary reflection surface is further steeper, and the incident light is focused and reflected to the upper end of the side wall of the light guiding portion, so that the condition of total reflection angle is satisfied, and the incident light can be totally reflected and propagated in the light guiding portion. In the optical structure designed by the method according to the light concentration ratio and the alignment angle tolerance range, the ratio of the top caliber D of the secondary optical element to the upper caliber D of the main reflector can be generally less than 0.15.
The distance between the incident surface and the secondary reflecting surface of the secondary optical element can be reduced, or the curvature of the secondary reflecting surface can be adjusted to be steeper, as shown in fig. 3B, at this time, part of the reflected light, usually the upper part of the reflected light, is reflected by the secondary reflecting surface of the secondary element, and is not directly incident into the light guiding portion, but irradiates the incident surface at an angle satisfying total reflection, and is incident into the light guiding portion after the incident surface is totally reflected, so that the caliber size of the element can be further reduced by the design. As shown in fig. 4, in order for such light rays entering the light guide portion by total reflection from the incident surface to be capable of total reflection propagation, it is required that an angle α between a tangent line of the incident surface portion, which is irradiated by the light rays reflected by the secondary reflection surface, and a horizontal direction satisfies θ < α <90 °, and an incident angle β >90 ° +θ—α of the light rays reflected by the secondary reflection surface, where θ is a total reflection angle of the secondary optical material.
As shown in fig. 3C, the distance between the incident surface and the secondary reflection surface is further compressed, at this time, the uppermost part of the light is incident from the incident surface, is reflected by the upper part of the secondary reflection surface of the secondary element for the first time, the reflected light is incident on the incident surface, is totally reflected by the incident surface, is again incident on the lower part of the secondary reflection surface, is reflected by the lower part of the secondary reflection surface for the second time, and is incident on the light guide part, and at this time, the secondary optical element with a smaller size is obtained. A secondary optical element having a compact refractive-reflective structure may have light reflected twice by the secondary reflecting surface and totally reflected once by the incident surface, light reflected once by the secondary reflecting surface and totally reflected once by the incident surface, and more light reflected once by the secondary reflecting surface and directly entering the light guiding portion. If the distance between the entrance face and the secondary reflecting face is small enough, there may be also light rays in which the incoming refracted light rays are reflected more times between the entrance face and the secondary reflecting face and then enter the light guiding portion.
According to the optical structure optimally designed by the method, the ratio of the top end caliber D of the secondary optical element to the upper end caliber D of the main reflector can be controlled within 0.12.
Example 2
A sunlight collecting optical device of this embodiment is substantially the same as that of embodiment 1 except that:
As shown in fig. 6, the primary mirror includes 4 mirror units of the same structure, and the secondary optical element includes 4 optical element units of the same structure;
the 4 reflecting mirror units with the same structure are rotationally spliced around the central shaft to form a rotationally symmetrical body, and the 4 optical element units with the same structure are rotationally spliced around the central shaft to form a rotationally symmetrical body;
the rotation angle of the rotation symmetry body is 90 degrees.
The part of the reflecting surface corresponding to each fixed rotation angle is a paraboloid, a hyperboloid, an ellipsoid or a free-form surface.
The part of the incident surface corresponding to each fixed rotation angle is a plane, a paraboloid, a hyperboloid, an ellipsoid, a sphere or a free-form surface;
The portion of the main mirror with respect to each of the fixed rotation angles is a paraboloid, a hyperboloid, an ellipsoid, or a free-form surface.
Example 3
A sunlight collecting optical device of this embodiment is substantially the same as that of embodiment 1 except that:
As shown in fig. 7, a sunlight collecting optical device of the present embodiment, in which the turning portions of the primary mirror and the secondary optical element are revolution bodies formed by rotation of the respective primary sectional profiles around a central axis;
the light guide part of the secondary optical element is a prism, the number of the side faces of the prism is 4, the upper surface is just equal to or larger than the bottom face of the steering part, and the lower surface is matched with the solar cell in size.
Example 4
A sunlight collecting optical device of this embodiment is substantially the same as that of embodiment 1 except that:
the steering part and the light guide part are integrated;
the secondary optical element is integrally pressed by adopting a precise compression molding technology.
Example 5
The present embodiment proposes a solar light collecting optical system, as shown in fig. 8, which includes the solar light collecting optical device, the receiving device, the mounting base plate, and the heat dissipating device described in embodiment 1;
The receiving device is arranged below the emergent surface of the secondary optical element of the sunlight collecting optical device; the heat dissipation device is arranged at the other end of the receiving device opposite to the secondary optical element; the mounting bottom plate is arranged above the heat dissipation device and is used for placing the sunlight collecting optical device and the receiving device.
The receiving apparatus includes a photoelectric conversion device and a circuit board.
The photoelectric conversion device is attached to the emergent surface of the secondary optical element in the sunlight collecting optical device, and the circuit board is arranged below the photoelectric conversion device;
The photoelectric conversion device is a high-concentration solar cell.
Example 6
The present embodiment relates to a sunlight collecting optical system substantially the same as embodiment 5 except that:
As shown in fig. 9, the solar light collection optical system further comprises a supporting heat conducting structure;
The supporting and heat conducting structure is arranged between the receiving device and the heat dissipating device.
The supporting thermally conductive structure is a material having a high thermal conductivity.
The material having high thermal conductivity is copper or aluminum.
The height of the supporting heat conducting structure is 50mm.
Example 7
The present embodiment relates to a sunlight collecting optical system substantially the same as embodiment 6 except that:
The height of the supporting heat conducting structure is 80mm.
Example 8
The present embodiment relates to a sunlight collecting optical system substantially the same as embodiment 6 except that:
the height of the supporting heat conducting structure is 100mm.
Example 9
The present embodiment relates to a sunlight collecting optical system substantially the same as embodiment 6 except that:
as shown in fig. 10, the length of the light guiding portion of the secondary optical element is 0, and the secondary optical element is connected with the heat dissipating device by the supporting and heat conducting structure.
Example 10
The present embodiment relates to a sunlight collecting optical system substantially the same as embodiment 6 except that:
The photoelectric conversion device is replaced by an LED light-emitting chip, and the sunlight collecting optical system is used as an illumination system for illumination.
Example 11
The embodiment relates to a light collecting method of a sunlight collecting optical system, which adopts the sunlight collecting optical system, and the method is that converging light rays reflected by a main reflector are directed to an incident surface of a corresponding secondary optical element, and enter a receiving device after being refracted, reflected and totally reflected by the secondary optical element, and the receiving device converts light energy into electric energy for subsequent use.
In the light collecting method, the converging light reflected by the main reflector is directed to the incident surface of the corresponding secondary optical element, and the focal point is approximately within the caliber of the secondary optical element, and may be located in front of the secondary reflecting surface of the secondary optical element, near the incident surface, or may be located behind the secondary reflecting surface after being refracted.
Claims (8)
1. A solar light collecting optical device, characterized in that the solar light collecting optical device comprises a primary mirror and a secondary optical element;
the main reflector and the secondary optical element are rotationally symmetrical bodies and have a common rotational symmetry axis;
the secondary optical element is arranged in a light focusing area of the main reflector;
the ratio of the top end caliber of the secondary optical element to the upper end caliber of the main reflector is smaller than 0.15;
The secondary optical element material is a solid transparent material and comprises a turning part and a light guide part;
the steering part is connected with the light guide part up and down or is a whole;
the light guide part comprises side walls and an emergent surface at the bottom, wherein the side walls are used for guiding light;
the turning part comprises an incident surface and a secondary reflecting surface;
the incident surface is a side surface of the turning part and faces the main reflecting mirror;
The secondary reflection surface is the top surface of the turning part;
and the secondary reflecting surface is plated with a high reflecting film.
2. A sunlight collecting optical device as claimed in claim 1 wherein the height of the turning portion is not more than 50mm and the length of the light guiding portion is in the range of 0-100mm and does not include 0mm.
3. A sunlight collecting optical device as claimed in claim 1 wherein the structure of the primary mirror and secondary optical element is replaced by a body of revolution having a common rotational symmetry axis.
4. A sunlight collecting optical device as claimed in claim 1 wherein the primary mirror comprises n mirror units of the same structure, the secondary optical element comprises n optical element units of the same structure, wherein n is a positive integer and n is not less than 2;
the n mirror units with the same structure are spliced around the rotation symmetry axis to form a rotation symmetry body, and the n optical element units with the same structure are spliced around the rotation symmetry axis of the mirror unit to form the rotation symmetry body.
5. A sunlight collecting optical device as claimed in claim 1 wherein the turning portion is joined up and down to the light guiding portion, the primary mirror and turning portion each being a solid of revolution having a common rotational symmetry axis;
The light guide part is a prism, the number of the side faces of the prism is at least 4, and the upper surface is just equal to or larger than the bottom face of the steering part.
6. A sunlight collecting optical device as claimed in claim 1, wherein the turning part is combined with the light guiding part up and down, the main reflecting mirror comprises n reflecting mirror units with the same structure, the turning part comprises n turning units with the same structure, wherein n is a positive integer, and n is equal to or greater than 2;
the n reflecting mirror units with the same structure are spliced around a rotation symmetry axis to form a rotation symmetry body, and the n steering units with the same structure are spliced around the rotation symmetry axis of the reflecting mirror units to form a rotation symmetry body;
The light guide part is a prism, the number of the side faces of the prism is at least 4, and the upper surface of the prism is just equal to or larger than the bottom face of the steering part.
7. A solar light collecting optical system for collecting solar energy, the solar light collecting optical system comprising a receiving device, a mounting base plate, and a heat dissipating device, characterized in that the solar light collecting optical system further comprises the solar light collecting optical device of any one of claims 1 to 6;
The receiving device is arranged below the emergent surface of the secondary optical element of the sunlight collecting optical device; the heat dissipation device is arranged at one end of the receiving device opposite to the secondary optical element; the mounting bottom plate is arranged above the heat dissipation device and is used for placing the sunlight collecting optical device and the receiving device.
8. A sunlight collecting optical system according to claim 7 wherein the sunlight collecting optical system further comprises a supporting and thermally conductive structure;
The supporting and heat conducting structure is arranged between the receiving device and the heat dissipating device.
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| CN101771370A (en) * | 2009-09-30 | 2010-07-07 | 新疆维吾尔自治区新能源研究所 | Solar power generator realizing multiplied condensation by utilizing secondary reflection method |
| CN103926684A (en) * | 2014-03-22 | 2014-07-16 | 吉林大学 | Tracking point-focusing high-power condenser |
| CN209472592U (en) * | 2019-03-06 | 2019-10-08 | 许涛 | A kind of sunlight collection Optical devices and system |
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| JP2006322696A (en) * | 2005-05-20 | 2006-11-30 | K & T Giken:Kk | Heat storing and insulating device utilizing solar heat by combination of reflector with lens |
| CN201117666Y (en) * | 2007-10-24 | 2008-09-17 | 陈祖培 | Light gathering solar cell assembly |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101771370A (en) * | 2009-09-30 | 2010-07-07 | 新疆维吾尔自治区新能源研究所 | Solar power generator realizing multiplied condensation by utilizing secondary reflection method |
| CN103926684A (en) * | 2014-03-22 | 2014-07-16 | 吉林大学 | Tracking point-focusing high-power condenser |
| CN209472592U (en) * | 2019-03-06 | 2019-10-08 | 许涛 | A kind of sunlight collection Optical devices and system |
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