Apparatus for collecting sunlight

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Drawings

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lens system is unnecessary, the registering operation of

APPARATUS FOR COLLECTING SUNLIGHT the focus point of the lens system with the inlet of the light conductor, which is quite dangerous and requires

This is a continuation of application Ser. No. 368,746, very great skill by the operator, can be completely filed Apr. 15, 1982, now abandoned. 5 eliminated.

Field of the invention brief description of the drawings

The present invention relates to a novel sunlight en A preferred embodiment of the invention will now be ergy collector. More particularly, the present invention described in detail with reference to the accompanying relates to an apparatus in a fixed position for collecting 10 drawings, wherein the same reference numerals are sunlight, in which incidented parallel components of used to designate similar parts throughout the different diffuse radiation of sunlight can be concentrated, with views, in which:

out using a complicated lens system, and introduced FIGS. 1 through 3 are vertical longitudinal sectional into a light conductor, or guide, at a high efficiency. views showing the construction of an apparatus for 15 collecting diffuse radiation of sunlight according to the

BACKGROUND OF THE INVENTION present invention.

Recently, energetic developments and research have DETAILED DESCRIPTION OF THE been made in various fields for effective utilization of sunlight energy with a view to meeting the requirement INVENTION of saving energy. 20 FIG. 1 is a vertical longitudinal sectional view illus I was quick to note the effective utilization of sunlight trating the construction of one embodiment of the pres energy for illumination and have made various propos ent invention. Reference numeral 10 denotes an appara als. The most effective utilization of sunlight energy is tus for collecting sunlight according to the present in to utilize sunlight energy in the form of light energy vention. As shown in FIG. 1, the apparatus is con directly for illumination in the room without converting 25 structed, for example, in the form of a cylinder. On the it to other forms of energy, such as electricity or heat. top of the cylinder 10 a relatively wide entrance aper In the known prior art there is proposed an apparatus ture 11, exposed to incident diffuse radiation, is pro capable of transmitting sunlight collected on the exte vided and a relatively narrow exit aperture 12 is pro rior of a house to a place where illumination is required, vided on the bottom of the cylinder 10 to which a light e.g., the interior of a room, by means of a light conduc 30 conductor 13, such as an optical fiber 13, is fixedly tor. For this purpose, in the prior art, sunlight is concen inserted.

trated by using a lens system, for example, a compli On the inner wall of the cylinder 10 a series of tapered cated arrangement of Fresnel lenses, and is introduced surfaces, symmetrical about the cylinder axis, are into the light conductor. In addition, since the above formed. Said tapered surfaces are made with a total mentioned apparatus is mainly intended to collect direct 35 reflection surface.

radiation of sunlight, it is necessary for said apparatus to During operation of the apparatus, incidented paral operate precisely and smoothly to track the movement lel components of diffuse radiation, which are parallel of the sun. to the longitudinal axis of the cylinder 10, enter from With this apparatus, the tracking mechanism of the the relatively wide entrance aperture 11, reflect on the apparatus is apt to become complicated, the positioning 40 tapered surfaces, are concentrated at the relatively nar of the lens system is difficult, and the registering opera row exit aperture 12 and, finally, are introduced into the tion of the focus of the lens system with the inlet of the light conductor 13, at a high efficiency. Consequently, light conductor is quite dangerous, as well as requiring the captured diffuse radiation by the cylinder 10 may be very great skill by the operator. transmitted to a place where illumination is required, by Other known prior arts have employed a parabolic 45 means of said light conductor 13.

reflector for concentrating direct radiation of sunlight In other words, the inner wall of the cylinder 10 has at a focus point at which a light conductor is disposed. a plurality of discrete tapered surfaces (for example the However, a parabolic reflector, in order to provide four tapered surfaces S4, S3, S2 and S1 shown in FIG. (1) effective concentration, is comparatively large and re contiguously arranged in series along the axis of the quires a precise parabolic surface. 50 cylinder. The surfaces S4, S3, S2 and S1 are the inner, Thus, the optimum apparatus of this kinds was not reflective surfaces of portions 104, 103, 102 and 101 re achieved until the present. spectively. Each surface is linear when viewed in longi

Summary of the invention

tudinal cross-section. Similar surfaces are present in the structures shown in FIG. 2 and 3. The surfaces S4

The present invention is directed to a collecting appa 55 through S1 appear as lines when viewed in longitudinal ratus, used in a fixed position, for collecting parallel cross-sections.

components of diffuse radiation of sunlight, i.e., the As can be seen in FIG. 1, the inner wall of the cylin scattered sunlight reflecting on molecules or suspending der 10 is provided with, for example, four tapered sur corpuscles in the atmosphere and the reflected sunlight faces. Supposing that the tapered angles 61, 62, 63 and from the surface of the earth, and is not directed to an 60 64 of the respective portions 101, 102, 103 and 104 are 20, apparatus for collecting the direct radiation of sunlight. 10, 5' and 2.5, respectively, and supposing that The invention as claimed is intended to provide an X1=X2 = 10.9 mm, X3 = 15.7 mm, X4= 11.8 mm, apparatus for collecting diffuse radiation of sunlight, in Y1=30 mm, Y2 = 60 mm, Y3=180 mm, Y4=270 mm which incidented parallel components of diffuse radia and the diameter of the exit aperture do is 10 mm, then tion can be concentrated, without using a lens system, 65 the following relations can be derived. and effectively introduced into a light conductor, so d1 =31.8 mm, d2=53.0 mm, db3=84.4 mm, d4=108.0 that the apparatus is simple in construction and low in mm and resulting with db42/dbo2 s 116.7. When the re manufacturing cost. Furthermore, since a complicated flective loss can be assumed as being negligibly small, 4 the optical energy at the exit aperture 12 will be about cable 13. Thus, the use of a plurality of said cylinders, 117 times the density than that at the entrance aperture each having its entrance aperture on the same plane, is 11. of benefit in increasing the collection of the solar en The present invention will now be described in more ergy.

detail with reference to FIG. 1. In the preferred embodiments of this invention, the As mentioned previously, according to the present apparatus is described as being cylindrical in form; how invention, four tapered surfaces, being arranged in se ever, square or polygon forms can be used so as to ries, are provided on the inner wall of the cylinder 10. eliminate spaces between the circular entrance aperture, Therefore, when the parallel components of the diffuse which occurs in the case of the cylinder being used. radiation are received in the entrance aperture 11, the 10 Should the container take the shape of a square or diffuse radiation incidented at the range between L3 polygon form, the container would include a plurality through L4 is reflected on the portion 104, and is inci of discrete reflective tapered surfaces continguously dented and reflected on the portion 102, and finally arranged in succession along the length of the con introduced into the exit aperture 12. The diffuse radia tainer. Each surface would be linear when viewed in tion received near the point L4 is finally introduced into 15 the right-side point P; alternatively the natural light longitudinal invention has been described in detail with par received near the point L3 is finally introduced into the ticular reference to preferred embodiments thereof, but left-side point Q of the exit aperture 12. In such a case, it will be understood that reasonable variations and the portions 103 and 101 are not utilized as the reflective modifications are possible without departing from the surface of said received diffuse radiation. 20

The diffuse radiation incidented at the range between spirit and scope of the invention.

I claim

L2 through L3 is multiply reflected on the portions 103 1. A sunlight collector used, in particular, for collect and 101 and is finally introduced into the exit aperture ing diffuse 12. radiation of sunlight comprising: Also the diffuse radiation incidented at the range 25 a cylinder having a relatively wide entrance aperture, between L1 through L2 is merely reflected on the por for receiving the parallel components of diffuse tion 102 and is introduced into the exit aperture 12. radiation which are parallel to the longitudinal axis However, the diffuse radiation incidented at the range of the cylinder, and a relatively narrow circular from the center Lo of the entrance aperture 11 through exit aperture, for introducing concentrated diffuse L1 cannot be satisfactorily introduced into the exit aper 30 radiation in said cylinder into a light conductor; ture 12. This is based on the relatively large tapered an inner wall of said cylinder having a countable angle 61 of the portion 101. For this reason, the addi number of discrete conical surfaces contiguously tional lens system 14 is provided on the longitudinal axis arranged in series along the axis of the cylinder and of the cylinder 10, so that the concentrating and intro having substantially a total reflection surface on ducing of the diffuse radiation between L0 and L1 into 35 each of said conical surfaces, each of said surfaces the exit aperture 12 can be achieved. being linear when viewed in longitudinal cross-sec Another embodiment of the present invention is tion; and shown in FIG. 2. The cylinder 10 is provided with three the angle of each of said conical surfaces is increased portions 101, 102 and 103. Supposing that 61 = 10, from the top to the bottom of the cylinder, so that 02=5, 63=2.5, X1 -9.4 mm, X2 = 9.9 mm, X3 = 14.7 40 the incidented diffuse radiation from said entrance mm, Y1=53.3 mm, Y2 = 112.6 mm, Y3=394 mm, aperture is reflected on said tapered surfaces and dbo= 10 mm and b3 = 77.9 mm, then the following rela concentrated into said exit aperture for introduc tion can be derived. tion into said light conductor. db3/cbos 60.7 2. A sunlight collector according to claim 1, wherein 45 the angle of each of said conical surfaces is not more

Thus, the optical energy at the exit aperture 12 will be than two times that of the tapered surface arranged about 60 times the density than that of the entrance upstream3. A thereof.

sunlight collector according to claim 1 wherein aperture 11. said inner wall of said cylinder comprises no more than A further embodiment of the present invention is shown in FIG. 3. The cylinder 10 is provided with four 50 four discrete conical surfaces.

portions 101, 102, 103 and 104. Supposing that 01=20, radiationdevice 4. A for collecting and concentrating diffuse of sunlight for introduction into a light con 692= 10, 83=5, 84=2.5. X = 7.7 mm, X2 = 17.1 mm, ductor, said device comprising:

mm, Y3=157.0 mm, Y4= 467 mm, dbo= 10 mm, 55 a container having a longitudinal axis, an entrance d1 = 25.4 mm, b2 = 44.2 mm, d3 = 112.8 mm and aperture for receiving components of diffuse radia db4 = 153.6 mm, then the following relation can be de tion which are substantially parallel to said axis, a rived. circular exit aperture, and at least one inner wall including three discrete conical surfaces contigu db4/dboas 236 ously arranged in succession along the length of 60 said container from said entrance aperture to said

Thus, the optical energy at the exit aperture 12 will be exit aperture, each of said surfaces providing an about 236 times the density than that at the entrance area of total reflection, each of said surfaces being aperture 11. linear when viewed in longitudinal cross-section; As can be easily recognized from the above descrip whereby incident diffuse radiation entering said con tion, by using the cylinder according to the present 65 tainer through said entrance aperture is reflected invention, substantially all of the parallel components of on said tapered surfaces and concentrated thereby the diffuse radiation incidented from the entrance aper into said exit aperture for introduction into a light ture 11 can be introduced into the optical conductor conductor.

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5. The collector device according to claim 4 wherein said container from said entrance aperture to said each of said conical surfaces is arranged at an angle of exit aperture, each of said surfaces providing an inclination with respect to a line parallel to said axis, area of total reflection and being conformed so that said angles of inclination increasing from said respective when viewed in longitudinal cross section, said surface nearest said entrance aperture to said respective 5 surfaces appear as linear; surface nearest said exit aperture. each of said conical surfaces arranged at an angle of 6. The collector device according to claim 5, wherein inclination with respect to a line parallel to said each of said angles of inclination is less than said angle axis, said angles of inclination increasing from said of inclination of said respective surface upstream there respective surface nearest said entrance aperture to from. 10 said respective surface nearest said exit aperture; 7. A device for collecting and concentrating diffuse whereby incident diffuse radiation entering said con radiation of sunlight for introduction into a light con tainer through said entrance aperture is reflected ductor, said device comprising: on said tapered surfaces and concentrated thereby a container having a longitudinal axis, an entrance into said exit aperture for introduction into a light aperture for receiving components of diffuse radia 5 conductor.

tion which are substantially parallel to said axis, a 8. A sunlight collector according to claim 7 wherein circular exit aperture, and at least one inner wall the angle of each of said conical surfaces is increased including three discrete conical surfaces contigu from the top to the bottom of sthe container. ously arranged in succession along the length of k s