The present invention relates to a solar collector optics system which is efficient and provides a high concentration factor.
Current solar power optics systems which function to also concentrate light are complex and costly to manufacture. These solar power optics systems are typically composed of a large molded reflector protected by a clear cover optic concentrating light on a glass optic. Many of these solar power optics systems also incorporate what is referred to as a “concentration factor.” The concentration factor is the amount or ratio in which the light passing through the system is concentrated and directed to a light receiving device, such as a photocell. The higher the concentration factor, the greater amount of energy can be harnessed from the light passing through the system.
Some of the solar power optics systems use fresnel optic systems, which are simple to combine with the cover plate. However, these types of systems suffer significant losses in efficiency as the concentration factor increases. To increase the concentration factor, the draft angle used during the molding of the fresnel lens is changed. However, the required draft angle for molding and the loss of efficiency with high angle refraction reduce overall efficiency. Area efficiency of the fresnel optic is also decreased as the concentration factor is increased.
Accordingly, there exists a need for a solar power optics system which is highly efficient, and also has a high concentration factor.
The present invention is a solar collector optic system having a plurality of optics and a plurality of concentrators, where the plurality of optics directs light to the plurality of concentrators.
In one embodiment, the present invention has a first fresnel optic and a second fresnel optic, and a first concentrator which is part of a first row of concentrators, and a second concentrator which is part of a second row of concentrators. The first concentrator has a focal line extending through a portion of the first optic, and the second concentrator has a focal line extending through a portion of the second optic. A row of concentrators and one of the optics make up an array. In one embodiment, there are four arrays, but it is within the scope of the invention that more or less arrays maybe used.
Each optic has a plurality of prisms which has a progressive light distribution function. Both the first optic and the second optic are formed with one or more of the plurality of prisms, such that as each of the plurality of prisms of the first optic is located further away from the focal line of the first concentrator, each of the plurality of prisms directs a greater amount of light to the second concentrator compared to the first concentrator. Also, as each of the plurality of prisms of the second optic is located further away from the focal line of the second concentrator, each of the plurality of prisms directs a greater amount of light to the first concentrator compared to the second concentrator. Each optic functions to concentrate light prior to the light entering a concentrator, and each concentrator further concentrates the light, and directs the light to a photocell.
The cost of manufacturing the solar collector optics system of the present invention is reduced by creating an extruded optic made up of several fresnel optics that concentrate light in one direction. Each fresnel optic used in the system of the present invention maintains high area and optical efficiency by concentrating light in adjacent focal lines. The fresnel optics are specifically shaped to direct light that would be lost in a standard fresnel optic to the adjacent focal line where the light is collected by the photocells in an adjacent array. The line of concentrated light is further concentrated by a secondary optic or concentrator to reach the desired 2000:1 or 2500:1 system concentration.
Accordingly, it is an object of the invention to develop a lower cost solar concentrator system that can achieve high concentration factors in the 2000:1 range or 2500:1 range, while maintaining good area efficiency.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Referring to the Figures generally, a solar collector optic system is shown generally at 10. The system 10 has an optic 12 spaced at a distance 14 from a plurality of concentrators, shown generally at 16. In this embodiment, there are four rows of concentrators 16A,16B,16C,16D. There is also a plurality of photocells 18, with one photocell 18 being used to collect light from each of the concentrators 16.
The optic 12 is made up of a plurality of fresnel optics 20 either formed separately and placed adjacent one another, or integrally molded together as shown in
The optic 20 has at least one arcuate portion or arcuate elongate central portion 22, and a set of prisms having a plurality of prism elements. More specifically, each fresnel optic 20A,20B,20C,20D has an arcuate portion 22, and on each side of the arcuate portion 22 is a plurality of stepped portions or prisms. Each of the fresnel optics 20A,20B,20C,20D is substantially similar, therefore, the first fresnel optic 20A only will be described. With reference to the first fresnel optic 20A, there is a first plurality of prisms on the left side of the arcuate portion 22, and a second plurality of prisms on the right side of the arcuate portion 22. The first plurality of prisms and the second plurality of prisms are substantially mirror images of each other, making the fresnel optic 20A substantially symmetrical.
In further regard to the first plurality of prisms, there is a first prism 24 integrally formed with the arcuate portion 22 and a second prism 26, and the second prism 26 is also integrally formed with a third prism 28. The third prism 28 is integrally formed with a fourth prism 30, and the fourth prism 30 is integrally formed with a fifth prism 32. The fifth prism 32 is integrally formed with a sixth prism 34, but the sixth prism 34 is also part of the adjacent fresnel optic 20. The arcuate portion 22 and each of the prisms 24,26,28,30,32,34 focus light entering the optic 20 through an input surface 36 formed as part of the fresnel optic 20.
Light entering the input surface 36 passes through the optic 20 and exits out of either of the arcuate portion 22 or the prisms 24,26,28,30,32,34. Each prism 24,26,28,30,32,34 has an arcuate surface 38 and a substantially straight surface 40, however, the shape of these surfaces 38,40 varies, depending upon the shape of the respective prism 24,26,28,30,32,34.
With specific reference to
More specifically, a portion of light from each arcuate portion 22 and a portion of light from each prism 24,26,28,30,32,34 is directed to each of the concentrators 16A1,16B1. The amount of light directed to the concentrators 16A1,16B1 from the arcuate portion 22 and the prisms 24,26,28,30,32,34 depends upon the shape of the arcuate portion 22 and the shape of each prism 24,26,28,30,32,34. The first fresnel optic 20A is designed such that the further the prism is away from the arcuate portion 22 (when looking at
Each row of concentrators 16A,16B,16C,16D extends the length of the optic 20, and therefore, the light exiting from each of the fresnel optics 20A,20B,20C,20D enters the input surfaces 42 of the concentrators 16. The light received by the input surfaces 42 depends upon the location of each concentrator 16. By way of example and with reference to the prisms 24,26,28,30,32,34 on the right-hand side of the first fresnel optic 20A shown in
For example, in this embodiment, ninety-five percent of the light from the first prism 24 of the first fresnel optic 20A is directed to the input surface 42 of each concentrator 16 in the first row of concentrators 16A, and five percent of the light from the first prism 24 of the first fresnel optic 20A is directed to the input surface 42 of each concentrator 16 in the second row of concentrators 16B.
Furthermore, ninety percent of the light from the second prism 26 of the first fresnel optic 20A is directed to each input surface 42 in the first row of concentrators 16A, and ten percent of the light from the second prism 26 of the first fresnel optic 20A is directed to each input surface 42 of the second row of concentrators 16B. Eighty percent of the light from the third prism 28 of the first fresnel optic 20A is directed to each input surface 42 of the first row of concentrators 16A, and twenty percent of the light from the third prism 28 of the first fresnel optic 20A is directed to each input surface 42 of the second row of concentrators 16B. Seventy percent of the light from the fourth prism 30 of the first fresnel optic 20A is directed to each input surface 42 of the first row of concentrators 16A, and thirty percent of the light from the fourth prism 30 of the first fresnel optic 20A is directed to each input surface 42 of the second row of concentrators 16B. Sixty percent of the light from the fifth prism 32 of the first fresnel optic 20A is directed to each input surface 42 of the first row of concentrators 16A, and forty percent of the light from the fifth prism 32 of the first fresnel optic 20A is directed to each input surface 42 of the second row of concentrators 16B.
Fifty percent of the light from the sixth prism 34 of the first fresnel optic 20A is directed to each input surface 42 of the first row of concentrators 16A, and fifty percent of the light from the sixth prism 34 of the first fresnel optic 20A is directed to each input surface 42 of the second row of concentrators 16B. This is because the surfaces 38,40 of the sixth prism 34 are substantially the same shape, and the sixth prism 24 forms part of both fresnel optics 20A,20B.
This progressive light distribution also applies to the second fresnel optic 20B. As mentioned above, the sixth prism 34 is part of both fresnel optics 20A,20B, and the second fresnel optic 20B has several prisms 24,26,28,30,32,34 which function to provide a progressive light distribution in the same way as the prisms 24,26,28,30,32,34 of the first fresnel optic 20A. The prisms 24,26,28,30,32,34 on the left-hand side of the second fresnel optic 20B will be used to describe an example of the operation of the second fresnel optic 20B.
In this embodiment, sixty percent of the light from the fifth prism 32 the second fresnel optic 20B is directed to each input surface 42 of the second row of concentrators 16B, and forty percent of the light from the fifth prism 32 of the second fresnel optic 20B is directed to each input surface 42 of the first row of concentrators 16A. Seventy percent of the light from the fourth prism 30 of the second fresnel optic 20B is directed to each input surface 42 of the second row of concentrators 16B, and thirty percent of the light from the fourth prism 30 of the second fresnel optic 20B is directed to each input surface 42 of the first row of concentrators 16A. Eighty percent of the light from the third prism 28 of the second fresnel optic 20B is directed to each input surface 42 of the second row of concentrators 16B, and twenty percent of the light from the third prism 28 of the second fresnel optic 20B is directed to each input surface 42 of the first row of concentrators 16A. Ninety percent of the light from the second prism 26 of the second fresnel optic 20B is directed to each input surface 42 of the second row of concentrators 16B, and ten percent of the light from the second prism 26 of the second fresnel optic 20B is directed to each input surface 42 of the first row of concentrators 16A. Ninety-five percent of the light from the first prism 24 of the second fresnel optic 20B is directed to each input surface 42 of the second row of concentrators 16B, and five percent of the light from the first prism 24 of the second fresnel optic 20B is directed to each input surface 42 of the first row of concentrators 16A.
While the progressive light distribution from the prisms 24,26,28,30,32,34 has been described using the various percentages mentioned above, it is within the scope of the invention that the prisms 24,26,28,30,32,34 may be shaped differently to distribute the light between the input surfaces 42 of the respective concentrators 16 differently as desired. The percentage of light from the first fresnel optic 20A divided between the two rows of concentrators steadily increases until fifty percent is sent to each row of concentrators 16A,16B by the sixth prism 34, and then eventually all the light is sent to the second row of concentrators 16B by the arcuate portion 22 of the second fresnel optic 20B.
Referring now to
Each of the concentrators 16 has a focal line 50, and the focal line 50 extends through the input surface 42 of the concentrator 16 such that the focal line 50 passes through the concentrator 16 and the photocell 18. The focal line 50 also passes though the center of the arcuate portion 22 of the fresnel optic 20, best seen in
As mentioned above, there are four rows of concentrators 16A,16B,16C,16D. In this embodiment, there are twelve concentrators in each row, best seen in
In operation, the light entering the input surface 36 of each optic 20 is concentrated towards the input surface 42 of each concentrator 16 because of the shape of the optic 20, the light is further concentrated by the concentrator 16. More specifically, in this embodiment, the light entering the input surface 36 of the optic 20 is concentrated at a ratio of 50:1 because of the shape of each fresnel optic 20A,20B,20C,20D; therefore, the light entering the input surface 42 of each concentrator 16 receives light that is fifty times the intensity of the light entering the input surface 36. Furthermore, the light that enters the input surface 42 of one of the concentrators 16 is concentrated again at a ratio of 50:1 because of the shape of the concentrator 16; therefore, the light entering the photocell 18 is at fifty times the intensity of the light entering the input surface 42, and is at twenty-five hundred times (2500:1) the intensity of the light entering the input surface 36 of the optic 20.
The increase in intensity of the light passing through the optic 20 and the increase in intensity of the light each concentrator 16 produces a high-efficiency solar collector, and minimizes the amount of light lost to inefficiencies that may occur depending upon the shape of the prisms 24,26,28,30,32,34. More specifically, the shape of the arcuate surfaces 38 and the substantially straight surfaces 40, and the angle of the surfaces 38,40 relative to one another and to the other parts of the optic 20, such as the input surface 36, effects the efficiency of the optic 20. The optic 20 used in the system 10 of the present invention, and more specifically the prisms 24,26,28,30,32,34, are shaped such that the light from the prisms 24,26,28,30,32,34 and the arcuate portion 22 of the first fresnel optic 20A is directed to the concentrators 16 in the first row of concentrators 16A or the adjacent row of concentrators 16B as shown in
The optic 20 may be extruded clear glass (or clear acrylic plastic which is resistant to high temperatures). Extruding the optic 20 allows a large area of the optic 20 to be created, and then cut into sections of a desired size, facilitating ease of manufacture. The optic 20 may be cut to any length, with a greater or lesser amount of concentrators 16 used in each row. One of the sections of the optic 20 is shown in
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the essence of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
This application claims priority to U.S. Provisional Application No. 61/397,870 filed on Jun. 17, 2010. The disclosure of the above application is incorporated herein by reference.
Number | Date | Country | |
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61397870 | Jun 2010 | US |