Solar energy collector

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Drawings

FIG. 9 is a pictorial view of a mold used to form the Concentrating unit 39 includes an inner strip 51 and lenses of the collecting unit of the preferred embodi an outer strip 53 of transparent thermoplastic such as, ment of the invention. for example, Lucite acrylic. Inner plastic strip 51 com

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reflectors that direct the sun's rays onto a fluid-carrying

SOLAR ENERGY COLLECTOR conduit. See, e.g., U.S. Pat. Nos. 3,923,039, issued to

Background of the invention

Fallbel on Dec. 2, 1975; 3,923,381, issued to Winston on

Dec. 2, 1975; 3,951,128, issued to Schoenfelder on Apr.

This is a division of application Ser. No. 956,220, filed 5 20, 1976; 3,964,464, issued to Hockman on June 22, on Oct. 30, 1978, now U.S. Pat. No. 4,305,383. 1976; 3,974,824, issued to Smith on Aug. 17, 1976; 1. Field of the Invention 3,982,527, issued to Cheng et all on Sept. 28, 1976; The present invention relates generally to systems for 3,985,116, issued to Kapany on Oct. 12, 1976; 3,990,430, collecting electromagnetic energy, and more particu issued to Robertson on Nov. 9, 1976; 3,991,740, issued larly to a system for concentrating the sun's rays onto O to Rabl on Nov. 16, 1976; 4,003,638, issued to Winston an energy collecting unit. on Jan. 18, 1977; 4,011,855, issued to Eshelman on Mar. 2. Description of the Prior Art 15, 1977; and 4,007,729, issued to Chao et alon Feb. 15, The prior art includes numerous systems for collect 1977. One of the principal objectives of these designs is ing and utilizing solar radiant energy. In such systems, to provide a collector that will direct the sun's rays onto the solar energy is typically used to heat a fluid, either 15 the conduit regardless of the position of the sun in the liquid or gas. Water and air are widely used. The heated sky. The reflectors of these designs are generally costly fluid is then conveyed, generally by means of pumps, to because they involve fairly complex geometrical con a remote location where it is stored in a insulated cham figurations, ber for subsequent utilization. Other research has been directed to mechanisms Systems for utilizing solar energy have included, for 20 known as heliostats that move the reflectors to track the example, systems for heating and/or cooling rooms or sun's path. See, e.g., U.S. Pat. Nos. 3,884,217, issued to buildings and the like. See, e.g., U.S. Pat. Nos. Wartes on May 20, 1975; 3,994,279, issued to Burak on 4,030,312, issued to Wallin et all on June 21, 1977; Nov. 30, 1976; and 4,011,858, issued to Hurkett on Mar. 4,028,904, issued to Anderson on June 14, 1977; 15, 1977. These mechanisms are extremely costly and 4,028,078, issued to Peckham on June 7, 1977; 4,018,581, 25 may require repair from time to time. issued to Ruffetal on Apr. 19, 1977; 4,007,776, issued to None of the prior art discloses the use of a plurality of Alkasab on Feb. 15, 1977; 3,242,679, issued to Puckett et converging lenses to focus the sun's rays onto a fluid alon Mar. 29, 1966; 2,713,252, issued to Jackson et alon transporting coil, nor onto a fluid-transporting double

Nov. 7, 1950; 2,342,211, issued to Newton on Feb. 22, 30 walled dome, nor onto an arch of flat hollow plates. 1944; German Pat. No. 473,729, issued Mar. 7, 1929. Also, none of the prior art teaches that the lenses in Other systems for utilizing solar energy have been pro cluded in such a plurality of lenses may be filled with a posed. See, e.g., 817 O.G. 1680, Aug. 31, 1965 re liquid. Further, the prior art does not disclose that a unit "Means and Method of Utilizing Solar Energy.” carrying such a plurality of lenses may be mounted on a Prior art solar energy systems have included both 35 house or other structure to concentrate and collect solar reflective and refractive means for concentrating and energy while allowing a portion of the sun's rays to pass directing the sun's rays. Such refractive means have through the unit into the interior of the house or struc included converging lenses for focusing the sun's rays ture.

on various devices. See, e.g., U.S. Pat. No. 389,125, SUMMARY OF THE INVENTION

28, 1971 re "Water-Heating Apparatus Utilizing Solar The present invention is a system for collecting solar Rays'; 814 O.G. 469-470, May 11, 1965 re "Solar En radiant energy that is very simple and inexpensive to ergy Heating Apparatus'. A plurality of such lenses manufacture. The system includes no moving parts, have been disposed on a spherical shell for concentrat resulting not only in ease and low cost of manufacture, ing solar energy onto a boiler inside of and concentric 45 but also in minimal repair and maintenance. The system with the shell. See U.S. Pat. No. 3,934,573, issued to is designed to collect the sun's rays regardless of the Dandini on Jan. 27, 1976. A plurality of such lenses position of the sun in the sky and regardless of the sea have also been combined into a compound lens. See, son. The system may be readily installed on a house or e.g., 871, O.G. 182, Feb. 3, 1970 re "High Temperature other structure. No substantial adjustment is necessary Lens Construction'. The lenses used for such purposes, 50 either at the time of installation or during use. The however, have typically been manufactured by fine system will concentrate and collector solar radiant en grinding and polishing and, as a result, are fairly costly, ergy while allowing a portion of the sun's rays to pass especially when the lenses are large. through into the interior of the house or structure. Concentrating lenses of the prior art have sometimes The system includes a concentrating unit and a col been filled with a liquid. The Roman philosopher Sen 55 lecting unit. The concentrating unit includes at least one eca (3 B.C.-65 A.D.) pointed out that a glass globe filled converging lens for concentrating the sun's rays onto with water could be used for magnifying purposes. E. the collecting unit. Each lens may be blow-formed from Hecht and A. Zajac, Optics, at 1 (Addison-Wesley, sheets of thermoplastic. Each lens may be hollow or 1976). Also, concentrating lenses in a fluid-filled filled with a liquid.

spheriod are found in nature, though the lenses them 60 The collecting unit includes a fluid-transporting selves may not be fluid filled. For example, the human member having a heat transfer fluid therein. Input and eye includes a biconvex lens on either side of which is output pipes connected to the fluid-transporting mem disposed a transparent fluid, i.e., the aqueous humor on ber carry the heat transfer fluid to and from the fluid one side, and the vitreous humor on the other. transporting member, respectively. The fluid-transport Of late, however, systems for collecting and utilizing 65 ing member may be a coil, or it may be a double-walled solar radiant energy have generally included reflective dome, or an arch of flat hollow plates. means for concentrating and directing the sun's rays. The collector further includes a backplate for fixing Extensive research has been directed toward designing the position of the collecting unit relative to the concen 7 trating unit such that the focus of each lens is on or near 6 to its optical axis A will be converged at a point f to the fluid-transporting member. The backplate may have one side of the focal point fin the focal plane of the lens, translucent portions for allowing a portion of the sun's the location of f in the focal plane depending upon rays to pass through the collector. angle 6. Thus, when the sun is positioned on optical axis BRIEF DESCRIPTION OF THE DRAWINGS A of lens 11, the Sun's rays 13 which are generally paral lel rays will be refracted generally as at 14 and concen

For a further understanding of the nature and objects trated proximate focal point f. When the Sun is posi of the present invention, reference should be had to the tioned at an angle 6 to optical axis A of lens 11, the sun's following detailed description, taken in conjunction rays will be concentrated proximate f.

with the accompanying drawings, in which like parts 10 The energy of the sun's rays converged by lens 11 are given like reference numerals and wherein: into cup 15 may be used to heat coil 27 directly, by FIG. 1 is an elevation, partly in section and with some focusing the rays on the coil, or indirectly, by focusing parts broken away, illustrating the use of a liquid-filled the rays in the heat transfer liquid 33 surrounding the lens to heat by solar radiant energy a coil disposed in a coil. In the latter case, the liquid 33 conveys heat energy liquid-filled cup; 15 to the coil 27. The coil 27 when heated directly or FIG. 2 is a pictorial view of a plurality of solar energy indirectly then conveys heat energy to the heat transfer collectors of the preferred embodiment of the present fluid indicated at 35, 37 flowing within the coil. The invention interconnected for use, for example, on the heated fluid within the coil may then be conveyed roof of a building; . .. through output tube 31 to an immediate use, or to a FIG. 3 is an elevation, partly in section and with some 20 storage area for subsequent use.

parts broken away, of the preferred embodiment of the Referring now to FIG. 3, there is shown a solar en solar energy collector of the invention; . ergy collector including an energy concentrating unit, FIG. 4 is a section of the preferred embodiment of the indicated generally at 39, and an energy collecting unit, present invention as taken along section lines 4-4 of indicated generally at 41. Energy concentrating unit 39 FIG. 3; 25 comprises a plurality of converging lenses 43 disposed FIG. 5 is an elevation, partly in section and with some in a curved, arch-like configuration over and spaced parts broken away, of an alternative embodiment of the apart from energy collecting unit 41. Unit 39 may, for solar energy collector of the invention; example, have the shape of a round arch. Collecting FIG. 6 is an elevation, partly in section and with some unit 41 is likewise disposed in a curved, arch-like config parts broken away, of another alternative embodiment 30 uration, which preferably conforms to the curvature of, of the solar energy collector of the invention; or is parallel to, the concentrating unit 39. A backplate FIG. 7 is a pictorial view of an alternative collecting 45 and side plates 47, 49 are provided for supporting the unit of the embodiment shown in FIG. 5; concentrating unit 39 and the collecting unit 41 in fixed, FIG. 8 is a pictorial view of an alternative collecting preferably parallel uniformly spaced apart relationship unit of the embodiment of FIG. 3; and 35 with each other.

FIG. 9 is a pictorial view of a mold used to form the Concentrating unit 39 includes an inner strip 51 and lenses of the collecting unit of the preferred embodi an outer strip 53 of transparent thermoplastic such as, ment of the invention. for example, Lucite acrylic. Inner plastic strip 51 com

Detailed description of the

prises curved central body portion 55 and first out 40 wardly extending flanged portions 57 at both ends of

PREFERRED EMBODIMENT OF THE the strip 51. Central body portion 55 is generally semi

Invention

circular in curvature and has parallel sides, i.e., body

Referring to FIG. 1, converging lens 11 refracts the portion 55 is generally of the shape of a hollow, right sun's rays 13 impinging upon the lens 11 and the re circular semicylinder.

fracted rays 14 are converged into a cup 15. Lens 11 45 Outer plastic strip 53 comprises curved main body includes a transparent curved portion 17 that is gener section or portion 59 (FIG. 4), second outwardly ex ally of the shape of a hollow hemisphere with an out tending flanged portions 61 at both ends of the strip 53, wardly extending circumferential flange 19 disposed and a plurality of spherical bulges or bubbles 63 on main around its edge. Lens 11 also includes a transparent disk body section or portion 59. Spherical bulges or bubbles portion 21 of substantially the same diameter as the 50 63 form the outer surfaces of converging lenses 43. The outer diameter of flange 19. Disk portion 21 is attached area 64 of main body section 59 between and to the sides to curved portion 17 at flange 19. The chamber 23 be of bubbles 63 conforms generally to the shape of a hol tween lens portions 17, 21 is filled with a transparent low, right circular semicylinder in like manner as does liquid 25. central body portion 55 of inner plastic strip 51. The A helical coil 27 of hollow tubing is disposed in cup 55 inner 51 and outer 53 strips are parallel, the curved 15. The tubing forming coil 27 extends from the bottom portion 55 of inner strip 51 being nested within and and the top of the coil through the walls of the cup 15 uniformly spaced apart from the curved section 59 of to form input tube 29 and output tube 31. Cup 15 con outer strip 53. Flanges 61 of outer strip 53 rest upon tains a heat transfer liquid 33 which fills the cup to a flanges 57 of inner strip 51 and are attached thereto, as level above the top of coil 27. A heat transfer fluid, the 60 by cement, thereby supporting outer strip 53 in fixed flow of which is indicated by arrows 35, 37, flows nesting relationship with inner strip 51. through the hollow tubing forming coil 27 and tubes 29, The space between the inner and outer strips, 51, 53, 31. The fluid indicated by 35, 37 may be either a liquid including the chambers between the inner surfaces 65 of Or a gas. bubbles 63 and the curved portion 55 of inner strip 51, Parallel light rays impinging upon lens 11 will be 65 is preferably filled with a transparent liquid 67. A liquid converged at focal point fof the lens when such parallel having optical properties similar to those of the plastic rays are also parallel to the optical axis A of the lens. used for the strips 51,53 should be used. Also, liquid 67 Parallel light rays that impinge upon lens 11 at an angle should be substantially immune from deterioration 8 when exposed to the sun. Liquid 67 is preferably min strip 53 and backing strip 77, as by cement. Plates 47, 49 eral oil such as, for example, Nujol. There is fluid com extend upward from curved section 59 as at 95, 97 to munication between the liquid-filled chambers under provide flanges through which bolts 99 may be inserted the bubbles 63 through passageways 69 between and to for attaching a plurality of collectors together into a the sides of the bubbles. larger unit (FIG. 2).

Bubbles 63, the corresponding liquid-filled chamber Backplate 45 and side plates 47, 49 may be made of beneath the bubbles and the respective segments of any suitably rigid material such as, for example, wood, curved strip portion 55 thereunder comprise meniscus plastic or metal. It is preferred to use a transparent type converging lenses 43 of concentrating unit 39. thermoplastic such as that used for concentrating unit Although it is preferred to employ liquid-filled lenses, 10 39, e.g., Lucite acrylic.

liquid 67 may be eliminated, in which case lenses 43 . . The plastic strips 51, 53 of energy concentrating unit would be hollow. Lenses 43 are preferably uniformly 39 may be manufactured quickly and inexpensively by a angularly spaced on unit 39 around its transverse axis or process known in the art as "blow-forming", wherein a its center of curvature. The number of lenses 43 that strip or sheet of plastic such as Lucite acrylic is warmed may be used depends, of course, upon the size of the 15 to a softened state at a temperature of 300 plus or minus lenses and the size of the unit 39. In a solar energy 30 F., is forced by air pressure into conformity with the collector of six feet in outside diameter, for example, inner surface of a rigid mold, and is then cooled and five to seven lenses often to twelve inch diameter may hardened. The mold for the outer strip 53 may have an be used. inner semicylindrical surface portion conforming in Collecting unit 41 comprises a serpentine coil 71 of 20 shape with the main body section 59, a plurality of tubing disposed in curved, arch-like configuration spherical recesses or depressions uniformly spaced under and uniformly spaced apart from or parallel to along the semicylindrical portion conforming in shape inner strip 51 of concentrating unit 39. Coil 71 may be with bubbles or bulges 63, and planar surfaces at the made of copper tubing of, for example, one-eighth inch ends of the semicylindrical portion conforming in shape to one quarter inch diameter. An insulative material 73 25 with flanged portions 61. The mold for the inner strip 51 such as, for example, fiberglass is disposed around the may have an inner semicylindrical surface portion con sides and the lower portion of the tubing for partially forming in shape with central body portion 55, and thermally insulating the coil 71, leaving an upper por planar surface portions at the ends of the semicylindri tion 75 of the tubing exposed to the lenses 43. A rigid cal portion conforming in shape with flanged portions backing strip 77 is disposed under the coil 71 for sup 30 57. Another mold that may be used to form outer strip porting the coil and the insulative material 73. Backing 53 is shown in FIG. 9 and has an inner semicylindrical strip 77 is attached at its ends to backplate 45, as by surface portion 98 conforming in shape with body sec cement. Backing strip 77 may be made of suitably rigid tion 59, a plurality of round holes 100 uniformly spaced metal or plastic or other materials. along the semicylindrical portion, and planar surfaces An input pipe 79 and an output pipe 81 extend 35 102 at the ends of the semicylindrical portion. When a through openings 80, 82, respectively, in backplate 45 softened plastic strip or sheet is placed in a mold, air and are connected to the ends of coil 71. Input pipe 79 pressure is applied to the interior of the mold so as to and output pipe 81 may be extensions of the tubing force the plastic against the inner surface of the mold forming coil 71, or they may be separate pipe joints into conforming contact therewith. When a mold such coupled to the coil. as that shown in FIG. 9 is used, the plastic is forced into A heat transfer fluid, the flow of which is indicated conformity with surfaces 98 and 102, and "pops" out by arrows 83, 85, is pumped by a pump 87 through input through holes 100, thus forming bubbles 63. When the pipe 79 to coil 71, through coil 71 and then away from plastic is then cooled and hardened, it may be removed coil 71 through output pipe 81. It will be appreciated, from the mold, retaining the shape of the inner surface however, that the direction of flow may be reversed if 45 of the mold.

desired, whereupon pipe 81 would serve as the input The plastic strips 51, 53 are attached together, as by pipe and pipe 79, the output pipe. The heat transfer fluid cement, at their ends at flanges 57, 61. A seal 101 of indicated by 83, 85 may be either a liquid or a gas. The rubber or the like is disposed between the flanges ex unit from which the fluid is pumped to coil 71 and to tending the width of the flanges in grooves cut in the which the fluid returns from the coil is indicated at 89. 50 adjoining surfaces of the flanges. Seal 101 prevents Unit 89 may be either a unit for immediate utilization of leakage of liquid 67 from between the flanges. the heat transfer fluid, such as a heater or an air condi Sealing strips 103 (FIG. 4) of rubber or the like are tioner, or a unit for storing the fluid for subsequent tightly wedged or sandwiched between the inner and utilization. outer plastic strips 51,53 at the sides thereof to contain Flanges 57 of concentrating unit 39 are disposed upon 55 liquid 67 between the strips and to prevent leakage of the upper surface of backplate 45, unit 39 being sup liquid 67 from the sides of the plastic strips. When plas ported thereby. Flanges 57 may be affixed to backplate tic strips 51,53 are cemented together and seal 101 and 45, as by cement. Collecting unit 41 is also supported by sealing strips 103 are in place, a filling hole may be backplate 45, input and output pipes 79, 81 being pro drilled in the outer strip 53 in the main body section 59 vided a tight fit in openings 80, 82 or otherwise being 60 thereof through which liquid 67 may be injected to fill secured within said openings, as by cement. the space between the strips, including the chambers Semicircular side plates 47, 49 provide additional under the bubbles 63. When the liquid 67 has been in rigidity and support for the elements of the solar energy jected so as to fill all the space between the strips, a collector of FIG. 3. Plates 47, 49 are attached at their rubber plug 105 is then wedged in the filling hole to seal straight edges 91, 93 (FIG. 4) to backplate 45, as by 65 the hole and prevent leakage of liquid 67 therefrom. cement. Plates 47, 49 extend perpendicularly upward Lenses 43 may be of any size from, for example, ten from backplate 45 and are affixed to the sides of curved inches to forty inches in diameter. For a typical home portion 55 of inner strip 51, curved section 59 of outer installation for heating or air conditioning purposes, 9 five to seven lenses of from ten to twelve inches in fixed position such that lenses 43 are exposed to the sun diameter are preferred. A concentrating unit 39 of four during the day and such that the track of the sun will feet in diameter will accommodate five of such lenses, pass sequentially through, or near, each of the optical and a unit 39 of six feet in diameter will accommodate axes of the lenses 43, several of such optical axes being seven of such lenses. shown at B, C, D and E. For example, the collector can The lenses 43 are preferably meniscus-type converg be mounted on the roof of a house with its backplate ing spherical lenses, but other shapes of converging horizontally disposed and with the semicircular arc of lenses may be used such as, for example, plano-convex lenses oriented in a generally east-west direction. In this or biconvex spherical lenses, or aspherical lenses. The position, optical axis D of the topmost lens will be verti shape of the lenses 43 depends, of course, on the shape 10 and the optical axes B, E of the lowermost lenses on of the mold used to blow-form the plastic strips or cal, each side of the arc will be at a small angle, typically sheets 51, 53 which form the surfaces of the lenses. If fifteen degrees or less, to the horizontal. Axis C of a lens the inner plastic strip 51 is formed with bubbles or adjacent the lowermost lens will be at an intermediate bulges thereon protruding inwardly toward collecting angle, such as forty degrees, to the horizontal, that is, unit 41 and corresponding to the bubbles 63 so that the 15 greater than such small angle but less than ninety de two sets of bubbles may be aligned, then lenses 43 grees, would be of the biconvex type. Alternatively, flat por on the the size value of such intermediate angle depending and number of lenses used and the spacing tions of sufficient size, e.g., squares with sides equal to between them.

the diameter of bubbles 63, may be provided on inner strips 51 in alignment with bubbles 63, thus forming 20 to The collector is set up for use by connecting coil 71 a usage system 89, such as a domestic absorption type plano-convex lenses. Other shapes of lenses may be air obtained by further varying the shape of the blow-form tank,conditioning system, a heating system or a storage through pipes 79, 81 and pump 87. A heat transfer ing molds.

Moreover, several types of converging lenses may be fluid, Therminols, such as one of Monsanto Industrial Chemical formed by providing the inner plastic strip 51 with the 25 isCo.'s forced through or Dow Chemical Co.'s Dowtherm, coil 71 by pump 87. Such a heat trans bubbles 63 and providing the outer plastic strip 53 with fer fluid may be, for example, an alkylated benzene. The appropriate curved surfaces in alignment with the bub particular fluid used will depend on the temperature bles on the inner strip. For example, by providing inner strip 51 with a plurality of bubbles bulging inward ranges it will be subject to in operation. Therminol 66, toward coil 71, plano-convex lenses may be formed by 30 for example, may be used where the operating tempera providing outer strip 53 with flat portions in alignment tures range from 15 F. to 650 F., and Therminol 88 with the bubbles; meniscus convex lenses may be may be used for temperatures up to 750 F. Applicant formed by providing outer strips 53 with curved sur. has found that an installation such as shown in FIG. 1, faces in alignment with the bubbles and oriented toward using Nujol inside the lens, may reach a temperature of coil 71; and biconvex lenses may be formed by provid 35 600' F. inside the cup.

ing outer strip 53 with curved surfaces in alignment At dawn, the sun's rays will be directed in a generally with the bubbles and oriented away from coil 71. horizontal direction toward one of the ends of the col Lenses 43 are disposed in concentrating unit 39 with lector. Assuming for the purposes of this description their optical axes lying in a single plane. All the lenses that the easternmost lens is the one with axis B, the sun's 43 have the same focal length. Applicant has found that 40 rays will be at an angle of, for example, fifteen degrees a plano-convex lens such as lens 11 shown in FIG. 1, to axis B. The sun's rays will generally be concentrated made of acrylic plastic three sixteenths inches thick, by this easternmost lens to one side of focal point fB in filled with mineral oil and having a diameter of twelve the focal plane of such lens and will impinge upon coil inches and a depth of four inches, has a focal length of 71 near the portion 107 of the coil proximate the focal eight inches. Each of the lenses 43 is spaced from the 45 point fB. This will cause the portion 107 of the coil to be coil 71 a distance equal to its focal length, so that all the warmed slightly. This in turn will cause the heat trans foci of all the lenses 43 are on or near the coil 71. fer fluid being formed through coil 71 by pump 87 to be The solar energy collector of FIG.3 may be installed warmed. The actual amount of warming will depend to in any location providing exposure to the sun's rays, for a large extent on the optical characteristics of the lens, example, on the roof of a house or other building, or on 50 including its aperture.

the ground. Preferably, such a location should be ex At the same time, the sun's rays are at a larger angle, posed to the sun's rays from dawn until dusk, because for example, forty degrees, to the adjacent lens, i.e., that the greater the exposure time to the sun's rays, the more lens having optical axis C, so that the rays are generally solar, energy will be collected by the invention. The concentrated farther to one side of the corresponding solar energy collector of FIG. 3 has its lenses disposed 55 focal point fo than is the case with the rays focused by generally in a semicircular arc and will be, therefore, the easternmost lens with respect to fB. Consequently, particularly effective when the collector is mounted the portion of the coil proximate fo will be warmed to a with its backplate horizontally disposed with respect to lesser extent than is coil portion 107, and the heat trans the ground and in a location having maximum exposure fer fluid will in turn be warmed to a lesser incremental time to the sun's rays. If a location having maximum 60 extent. Now, the sun's rays are at an increasingly larger exposure time cannot be found in the vicinity in which angle to the axes of successive lenses so that the rays are the invention is to be used, then it may be desirable to concentrated at points increasingly farther from the use a concentrating unit having less than a complete respective focal points, resulting in diminishing warm semicircular arc of lenses, the shape of the arc to be used ing of the coil, for example at coil portion 109, and corresponding to that portion of a complete arc that 65 hence the fluid, with respect to successive lenses. would be exposed to the sun's rays. Because axis D is essentially normal to the sun's rays Operation of the preferred embodiment of the collec at dawn and axis E actually extends away from the sun, tor of the invention includes securing the collector in a very little, if any, warming of the coil and the fluid 10 therewithin will be accomplished by the corresponding such as Lucite acrylic plastic is used for backplate 45, a lenses, and those between such lenses, at this time. portion of the sun's rays will pass through collecting At some point in time after dawn, the sun's rays will unit 39 and backplate 45 at strips S and into the room or be positioned on or near axis B of the easternmost lens. building. A translucent, non-transparent panel 111 may At such time, the sun's rays will be focused at focal be disposed between the collector and the observer if point fB by such lens. On a clear day, i.e., when the sun's desired, for example, as a part of the ceiling of the room, rays are primarily direct as opposed to diffuse, the tem to allow light to pass into the room while partially perature at the focal point of a lens of the type described masking the collector apparatus from view. For exam above may be approximately 600 F. when the sun is ple, a decorative or colorful panel may be used for panel positioned on or near its optical axis. Thus, coil portion 10 111 to provide aesthetically 107 is heated extensively at fp, as is the heat transfer panel may instead be used pleasing results. Such a fluid within the coil. Furthermore, the sun's rays are at thereby avoiding using both a backplate and a45separate for backplate itself, a smaller angle than at dawn to the adjacent and succes panel.

sive lenses, so that warming of the coil, and hence the fluid, by such adjacent and successive lenses is greater 15 of Ifa single energy usage demand is greater than the capacity than at dawn. As a result, fluid flowing through coil 71 be installedcollector, on the then a plurality of collectors may same roof and may be attached to is heated extensively at fB, and is heated further by the gether, for example, as shown in FIG. 2, to increase the adjacent and successive lenses in successively decreas total amount of solar energy collected, If a plurality of ing amounts.

It will be appreciated that during the course of a day, 20 collectors are used, the coils of the individual collectors the sun will be positioned on or near the axes of each may be connected in series so that the heat transfer fluid lens successively, e.g., on axes C, D and E. At such therein flows from one collector to the next, or the coils times, the portions of the coil proximate the respective may be individually connected to a common source, focal points of the lenses, and hence the fluid within the such as a large storage tank, so the fluid flows from the coil, will be warmed extensively. At the same time, the 25 common source, to one of the coils, and then back to the adjacent and successive lenses in both directions from common source. As shown in FIG. 2, adjacent collec the lens on whose axis the sun is positioned, i.e., in the tors are attached together by bolts 99 and nuts (not direction of the sun's apparent movement and in the side shown) inserted through holes in extensions 95, 97 of opposite direction, will concentrate the sun's rays to a plates 47, 49.

lesser degree and will warm the coil, and the fluid, in 30 Although the collector described above and shown in successively diminishing incremental amounts. FIGS. 3 and 4 is preferred, many variations in structure Furthermore, even when the sun is positioned be are possible.

tween and at an angle to the optical axes of two adjacent For example, the lenses may be disposed with their lenses, such as between axes B and C, the lenses corre axes in a plurality of planes rather than in a single plane sponding to such axes will concentrate the sun's rays in 35 as in the preferred embodiment. In such an alternative the manner previously described with respect to rays embodiment, the sun may be positioned on an optical arriving at an angle to an optical axis, and will warm the axis of a lens even if the sun passes over the collector at coil and fluid accordingly. In like manner, the lenses an angle to such a single plane. As a result, substantial adjacent to such two lenses in both directions, and the solar energy can be collected regardless of the season of lenses successive to them, will warm the coil and the 40 the year.

fluid in successively smaller increments. Thus, the alternative embodiment of the invention Thus, even though the collector has no moving parts, shown in FIG. 5 is especially suited for multi-season the sun's rays are collected continuously between sun use. In FIG. 5, there is shown a solar energy collector rise and sunset. The actual amount of solar energy col having a concentrating unit 113 and a collecting unit lected, of course, will vary during the course of a day 45 115. Concentrating unit 113 comprises inner and outer depending on the position of the sun relative to the transparent plastic domes 117, 119, respectively. Inner optical axes of the lenses, with the peak energy-collect dome 117 is nested within and spaced apart from outer ing periods occuring during those times when the sun is dome 119. The domes 117, 119 may be made from Lu positioned on or near one of the axes. cite acrylic plastic. The domes 117, 119 each have a As described above, the axes of the lenses are in a 50 body portion generally of hollow hemispherical config common plane. If the axis D of the topmost lens is verti uration, and have outwardly extending circumferential cal, then this common plane, is vertical. While such flanges 121, 123, respectively, at their edges. The domes positioning will give best results for positions on the 117, 119 are attached together, as by cement, at the equator during an equinox, the results for other geo flanges 121, 123, the lower surface of flange 123 being graphical locations at other times of the year may not be 55 cemented to the upper surface of flange 121. A circular optimum. Therefore, it may be desirable to fix the posi seal 125 of rubber or other suitable material is sand tion of the collector so that the average results are opti wiched between flanges 121,123 in opposing grooves mum over the course of a year. cut in the flanges so as to provide a fluid-tight sealed In addition to collecting solar energy for use in air connection between inner and outer domes 117, 119. conditioning and heating systems, the collector shown 60 A circular disk or backing plate 127 is connected to in FIG.3 may serve as a skylight in allowing a portion the lower surface of flange 121, as by cement. Plate 127 of the sun's rays to be transmitted through the collector is preferably made from transparent plastic, such as and into the interior of the room or building on the roof Lucite acrylic.

of which it is installed. At both ends of the collector, The body portion of outer dome 119 includes a plu there is a strip indicated at S between the coil 71 and the 65 rality of hollow, outwardly protruding convex bulges collector ends that is unobstructed by the coil when or bubbles 129 uniformly disposed about its surface. viewed from below, for example, from the interior of Bubbles 129 are generally spherical in shape and are like such a room or building. Thus, if a transparent material previously described bubbles 63 shown in FIG. 3. The 11 spherical portion of dome 119 between bubbles. 129 is Thus, in FIG. 6there is shown a solar energy collector indicated at 131. having a concentrating unit 39 of the preferred embodi The space between the inner and outer domes 117, ment and a modified collecting unit 151. Modified col 119, including the space between portion 131 and the lecting unit 151 includes an arched tube 153 of metal or inner dome and the space between the bubbles 129 and 5 other thermally conductive material, such as steel, sur the inner dome, is preferably filled with the transparent rounding the serpentine coil 71. The tube 153 has inserts liquid 67. Liquid 67 may be injected between the domes 155 attached to the tube just inside of its ends, as by through a hole drilled in the outer dome. A plug 231 of welding, for closing the tube. Inserts 155 have holes rubber or other suitable material is then wedged in the therein through which pipes 79, 81 extend for connec hole to seal it and prevent leakage of liquid 67 from the 10 tion to coil 71. Seals 157 are provided around the pipes hole. . . . .. 79, 81 where they pass through the holes in inserts 155 Inner and outer domes 117, 119 may be made by the to prevent leakage from around the pipes. Thermally blow-forming technique prevously described, using insulative material 158 is provided under the tube 153. appropriately shaped molds having either a smooth The tube 153 is filled with a heat transfer fluid 159, inner surface in the case of inner dome 117, or a plural- 15 such as Therminol or Dowtherm, which may be in ity of spherical depressions in an otherwise smooth jected into the tube through a hole in the tube, which is inner surface in the case of outer dome 119. then plugged or sealed. Additional heat transfer fluid, The bubbles 129, liquid 67 thereunder and the respec such as Therminol or Dowtherm, is pumped through tive adjacent surfaces of inner dome 117 comprise a coil 71 by pump 87.

plurality of meniscus-type convex lenses 133 like previ. 20 In operation, the lenses 43 concentrate the sun's rays ously described lenses. 43, shown in FIG. 3. Lenses 133 onto tube 153, which is warmed thereby. The fluid are all of the same focal length and are uniformly spaced within the tube and in contact therewith is warmed by from collecting unit 115 at a distance, such that the focal conduction of heat from the walls of the tube to the point of each lens is on or near the collecting unit 115. fluid. This fluid then helps distribute the heat through Collecting unit. 115 comprises, a double-walled dome 25 out the tube, and also to coil 71, by convection and 135 of metal or other thermally conductive material conduction. Since the fluid is in surrounding relation to such as, for example, steel. Dome 135 is of generally the coil 71, the heat is more uniformly imparted to coil hemispherical configuration and includes an inner wall 71 and, hence, to the additional fluid being pumped 137 and an outer wall 139 spaced therefrom. An annular therewithin. • member 141 is disposed between the inner and outer 30 In another alternative embodiment of the invention, walls adjacent to their edges and is connected to each the double-walled dome 135 of the collecting unit wall, as by welding. A layer of thermally insulative shown in FIG. 5 may be replaced by a coil 161 of cop material 142 is provided under inner dome wall 137. per tubing similar to coil 71 and shown in FIG. 7, only An input pipe 143 and an output pipe 145 are inserted convoluted to conform generally to hollow hemispheri through holes in diametrically opposed sides of annular 35 cal configuration.

member 141 and placed in communication with the In another alternative embodiment of the invention, space between the inner and outer walls 137, 139. An the arched coil 71 of FIG.3 may be replaced by a plu O-ring seal. 147 of rubber or the like is disposed in a rality of flat, hollow plates 163 as shown in FIG. 8, groove in member 141 around each pipe to prevent fluid connected together and forming an arch under the leakage from around the pipes. 40 lenses. Preferably, an equal number of plates 163 as In use, the collector is mounted so as to be exposed to lenses are provided, each plate being aligned with and the sun, as on a roof of a house. Since the lenses 133 are spaced from one of the lenses a distance equal to its disposed with their optical axes directed from a spheri focal length. A number of such plates 163 may be cal surface in a plurality of planes, the sun will be on or welded together into an arch, for example, or one large near one of the axes regardless of the position of the sun 45 plate may be bent or crimped into the proper shape. in the sky, whether summer or winter, spring or fall. In another alternative embodiment of the invention, The sun's rays will be concentrated by lenses 133 onto in place of a spherical or arched coil or a double-walled the outer surface of dome3 135, which will be warmed dome the collecting unit may include a flat coil or a thereby. single flat hollow plate horizontally disposed with re A heat transfer fluid 149 such as, for example, Ther- 50 spect to the concentrating unit. In this case it is still minol or Dowtherm, is forced by pump 87 through pipe preferred that the foci of the lenses are all on or near the 143 into the space between the dome walls. The fluid collecting unit, so lenses of different focal lengths 149 circulates through the dome and collects the heat should be used.

from the dome walls and then exits from the dome The above embodiments are merely exemplary of the through output pipe 145, whereupon it flows to utiliza- 55 possible changes or variations that may be made. tion system 89. In system 89, the solar energy collected Because many varying and different embodiments by the fluid is either utilized immediately or stored for may be made within the scope of the inventive concept later use. Upon the solar energy being spent, the fluid herein taught, and because many modifications may be 149 is pumped back to the dome 135 to collect more made in the embodiments herein detailed, it should be solar energy. 60 understood that the details described herein are to be It will be noted that in the alternative embodiment of interpreted as illustrative and not in a limiting sense. the invention shown in FIG. 5, the portion S' of the What is claimed as invention is: collector that is unobstructed by the dome 135 when 1. A solar energy collector, comprising: viewed from below, thus serving as the skylight portion concentrating means for concentrating solar radiation of the collector, will appear to an observer as an annular 65 including a plurality of converging lenses each ring. having a curved surface, an optical axis, a principal The collecting unit of the preferred embodiment of focus and a focal length, said concentrating means the invention may also be modified in various respects. including a first member and a second member of 12 transparent thermoplastic, said first and second generally to the shapes of hollow hemispheres, said members each having a body portion, said body inner dome body portion being nested within said portions being disposed in nested, spaced apart outer dome body portion, wherein said lenses all interrelationship, one of said body portions of said have the same focal length and said heat transfer members having a plurality of spaced apart hollow 5 unit includes a coil of tubing convoluted so as to hemispherical bubbles bulging away from the other have the shape of a hollow hemisphere disposed of said body portions and forming said curved under and concentric with said inner dome body surfaces of said lenses, said bubbles being integral portion, said coil being spaced from said lenses a with and part of said one of said body portions of distance substantially equal to said focal length of said members, the interior surface of each of said 10 said lenses.

bubbles defining a chamber, and each of said cham 2. Collector according to claim 1, wherein said pe bers being in communication with the space be ripheral portions of said domes include an outwardly tween said body portions of said members; extending circumferential flange around the edge of collecting means for collecting solar radiation includ each hemispherical body portion, said flanges each ing a fluid-transporting heat transfer unit; and 15 having an upper and a lower face, said flanges being frame means connected to said concentrating means interconnected and having such lower face of said and said collecting means for fixing the position of flange around said body portion of said outer dome each of said lenses relative to said heat transfer unit adjoining such upper face of said flange around said at a distance from said heat transfer unit substan body portion of said inner dome. tially equal to its focal length so that said focus of 20 3. Collector according to claim 2, wherein said con each of said lenses is located proximate said heat centrating means includes means for sealing the connec transfer unit, wherein said first and second mem tion between said flanges against fluid leakage, said bers each include a peripheral portion connected to sealing means including an annular rubber ring disposed and extending from said body portion for intercon between said flanges in opposing circular grooves cut in necting said first and second members, said first 25 such adjoining faces of said flanges. and second members being an inner and an outer 4. Collector according to claim 3, wherein said frame hollow dome, respectively, said bubbles forming means includes a rigid, flat circular disc connected to said curved surfaces of said lenses being uniformly such lower face of said flange around said body portion spaced on said body portion of said outer dome, of said inner dome and supporting said inner and outer said inner dome body portion and said outer dome 30 domes.

body portion exclusive of said bubbles conforming ck x: sk x: ck

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O united states patent and trademark office

Certificate of correction

INVENTOR(S) : Dan E. Bloxsom it is certified that error appears in the above-identified patent and that said Letters Patent is hereby corrected as shown below:

O Column 2, line 5l; change "collector" to -- collect --.

Column ill, line l3; change "prevously" to -- previously --.

Column 13, line l4; delete "Collecting" (first occurence).

() eigned and sealed this Nineteenth Day of October 1982

Seal

Attest:

o GERALDJ. MOSSINGHOFF Attesting Officer Commissioner of Patents and Trademarks