Solar energy collection

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lenses and fluid lenses is known in the art for focusing

SOLAR ENERGY COLLECTION solar energy. See, for example, U.S. Pat. Nos. 3,915,148; BACKGROUND OF THE INVENTION 3,125,091; 937,013; 3,965,683; 3,901,036; 60,109; 1. Field of the Invention 1,081,098; Japanese Pat. No. 28-2130, and Australian

Pat. No. 131,069. However, none of the known systems

The present invention relates to methods and appara is capable of converting and storing solar energy effi tus for concentrating and collecting solar energy for ciently and none can produce heat at an economical many uses including the conversion thereof to heat capital investment such that the use of solar energy is energy and/or electrical energy to be used for many competitive with other energies. The prior art also does purposes. The present invention also relates to the stor 10 not disclose obtaining temperatures in the order of a few age and use of heat energy during hours without sun or hundred degrees C. while also obtaining at the same with reduced sun. The present invention further relates time lower temperatures usable for home heating and to the treatment of water containing salt and/or other water heating or other purposes. Nor is there in the substances using fixed and portable apparatus and meth prior art a system which is capable of storing heat en ods according to the invention. More particularly, the 15 ergy from solar energy during periods of interrupted invention relates to methods and apparatus using fluid solar energy for any length of time and which also is and/or Fresnel concentrating lenses and lens systems capable of providing different temperatures simulta and elongated collectors comprising at least one fluid neously and also utilizing the luminous and infrared rays carrying conduit located at the foci of the lenses. of the sun. With respect to electrical generation, it is 2. Description of the Prior Art 20 known that concentrating the solar energy at a photoe The energy emitted by the sun corresponds to a high lectric cell will increase the electrical output of cell; temperature in the order of 6000 C., and is emitted in however, there is the disadvantage that the increased the form of radiation which arrives at the earth with a heat in the photoelectric cell resulting from the concen wavelength distribution comprising about 3% ultravio tration will also limit the cell output. Known photovol let rays, 42% visible light rays, and about 55% infrared 25 taic devices produce a maximum of about one watt per rays. It is well known that surfaces exposed to the sun hour per cell. Assuming a cost of $10 per photovoltaic collect at least to some degree the solar radiation and cell, a system using non-concentrated solar energy to that the absorption of this radiation results in a heating generate about 1 kilowatt per hour requires a capital of the material constituting the surface. It is also known cost of at least $10,000 which is not competitive for that electricity can be produced by photoelectric de 30 normal uses. With respect to solar stills, known stills vices exposed to the sun's rays. used for distillation of seawater have low efficiencies There have been many attempts in the past to collect and the cost of heating the water is high as the least and utilize pollution-free and essentially nonconsumable amount of heat required to vaporized the water is not solar energy to meet many energy needs. Much atten recovered from the condensation but rather is lost. tion has been directed to the conversion and utilization 35 In accordance with the invention the prior art draw of solar energy in the past few years because of the backs and disadvantages are substantially overcome and realization that fossil fuels are exhaustable and that a additional advantages realized. burning of these fuels produces pollution. Solar energy, on the other hand, is inexhaustable and available above SUMMARY OF THE INVENTION the clouds at an average energy level of approximately 40 The present invention is embodied in and carried out 1350 watts per horizontal square meter. A percentage of by methods and apparatus for concentrating, collecting, this energy, depending on atmospheric and weather storing and utilizing solar energy. In accordance with conditions, dust, pollution, etc., is available at the sur the invention, refringent less means concentrate the face of the earth during periods of sunshine which vary solar energy along a length at elongated collector up to about 4000 hours per year depending on location. 45 means containing at least one fluid therein. Further in Even more recently, the shortage of fossil fuels particu accordance with the invention, the lens means comprise larly oil and the high cost thereof have sparked new economical fluid or Fresnel-type lenses and lens systems attempts to harness the energy of the sun. As in the past, which focus the solar energy substantially along the however, fuels are still a lesser expensive source of length at the collector means along substantially contin energy and the same problems of high capital cost and 50 uous lines or in lines of substantially discrete points. the cyclic nature of the sun requiring storage capability Thus, the at least one fluid in the elongated collector have still not been satisfactorily solved. For example, may be efficiently heated to high temperatures in the refringent lens focusing systems, most using reflecting order of a few hundred degrees C. The fluid lenses are collectors and most including sun-tracking systems, advantageously made from separate upper and lower have heretofore been used but are uneconomical and 55 solar energy transmitting plates which are installed in impractical because of the high cost involved. A con frame means in a fluid-tight manner, or the fluid lenses ventional way for obtaining lower temperatures up to may be welded, extruded, or blown similar to glass or about 80 C. consists of using dark-colored panels plastic bottles. The fluid within the lenses preferably has which absorb the solar radiation, and combining these an index of refraction similar to that of lens plates. The panels with means circulating a heat-carrying fluid in a enclosure in the lens containing the fluid is advanta heat-exchanging manner with the panels. It is also geously communicated with the collector means to known to improve the efficiency of these systems by enhance performance. Still further in accordance with placing one or more glass plates above the panels to the invention, the elongated collector means comprises produce a greenhouse effect for reducing heat losses. a plurality of fluids, adjacent ones of which are contigu However, the efficiency of these panel systems is low, 65 ous. The fluids are preferably isolated and disposed in from about 30% to about 60%, and they require large adjacent conduits and the fluids preferably differ and spaces resulting in large heat losses, and they also re have varying boiling points. The theoretical focus or quire a high captial investment. The use of Fresnel-type foci of the lens means are preferably on the surface of or

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within the higher or highest boiling point liquid. In a returned to the system by means of the lens fluid and the preferred embodiment, the elongated collector means circulation thereof, thereby increasing substantially the comprises at least two conduits; one of the conduits efficiency of the system and the quantity of heated containing a first fluid having a first boiling point is water obtained from water to be distilled. Salt may be located within a second conduit containing a second produced from the resulting concentrated brine and fluid having a second boiling point. Preferably, the solar credit obtained from the sale thereof to lower the over energy is concentrated at the inner liquid which has a all cost of obtaining distilled water. According to one boiling point which exceeds that of the outer liquid. The embodiment of the invention, the still is portable and is conduits and fluids are solar energy transmitting or easily assembled and disassembled. Advantageously, opaque or darkened depending on the location of the 10 the stills are operative to distill seawater and brackish lens means focus. By solar energy transmitting it is water and may be used at sea, for example, on lifeboats, meant that the solar rays are substantially transmitted and in desert areas.

through the material as opposed to being absorbed and The collecting surface area of the apparatus of the with respect to the luminous rays of the sun is synony present invention is much smaller than the collecting mous with the word transparent. In this way, the fluid 15 surface area of flat panel systems and is from about 2% may be heated to different temperatures and accord to about 10% of the surface area of flat panel systems ingly can be utilized for different purposes, if desired. for comparable energy collection. Lower collecting Regulation of the fluid flow rates and selection of con surface areas result in lower heat losses, higher efficien duit sizes and shapes assists in providing different tem cies, lower cost for energy produced, and require lower peratures which may be utilized for different purposes. 20 investment cost. The apparatus may be enclosed ac Arrangement of multiple conduits carrying multiple cording to the invention to further reduce heat losses fluids in accordance with the invention can provide and form enclosed systems. Since the temperature of the energy for many different uses including a vapor and fluid can be raised to a relatively high value in the pres super-heated vapor for mechanical devices including ent invention, a variety of simultaneous uses are avail turbines. Avantageously, the lower boiling point fluid 25 able including using a plurality of fluids of different has a low latent heat of vaporization and is useful for boiling points for many different purposes. The higher this purpose. Additionally, heat is stored in the higher temperatures attainable and the use of multiple fluids boiling point fluid by permitting its temperature to rise permit heat storage during non-solar energy periods. during periods of solar energy to a temperature substan The higher temperatures permit the use of smaller stor tially higher than that of the lower boiling point fluid 30 age tanks or other storage means. For example, for the which may be used as a working fluid. Heat is removed same fluid, 2 times less space is required to store the from the higher boiling temperature fluid by, for exam same heat at 200 C. than at 80° C. The higher boiling ple, circulating the lower boiling point fluid past the point fluids and the heat storage capability obviate the higher boiling point fluid. The invention also provides need for antifreeze. According to the invention, diffuse for the union of individual systems to form larger com 35 solar energy representing up to about 40% of the solar posite systems. Thus, a high degree of concentration of energy received is concentrated at the collector means solar energy is possible. Still further in accordance with and thereby utilized which is not the case with reflect the invention, both the infrared and luminous rays of the ing concentrators. The efficiency of apparatus accord sun may be simultaneously utilized. Photoelectric cells ing to the invention is high and its cost is low in compar can be disposed at the collector means such that the ison to known systems and the cost of obtaining energy luminous rays are concentrated thereat for maximum competitive with fuels. Moreover, the present invention electrical energy production while the heat generated has the advantage of generating electricity, producing by the concentration of the infrared rays is removed by heat simultaneously or separately and storing heat and is one or more fluids in the collector means whose flow useful in many applications, thus increasing system effi rates and volumes may be regulated. Thus, in accor 45 ciency, utilization and amortizing the cost of the system. dance with the invention, the solar energy is concen Since reflective surfaces which do not reflect diffuse trated by a factor in the order of up to 50 to 100 so that solar energy are not required to practice the present one of the known cells is able to produce up to 50 to 100 invention, the need to maintain reflective surfaces watts per hour instead of 1 watt per hour during periods which weather easily and frequently require refurbish of sunshine. Further in accordance with the present 50 ing is obviated. Also, as will be more apparent hereinaf. invention, water may be distilled by locating the collec ter, tracking equipment is not essential to practicing the tor means in the water to be distilled, above which is present invention, particularly tracking equipment of positioned lens means and a downwardly sloping sub the type which follows the sun on a daily basis as the stantially smooth, preferably planar surface, whereby system is located east-west. Apparatus according to the water is evaporated and condenses on the smooth sur 55 invention can advantageously be combined with a con face which carries the condensed water to a collecting ventional heat pump producing and storing additional vessel positioned below the lower side thereof. Means heat from the surrounding air or water. This may be are provided to completely enclose the apparatus while particularly significant during winter months when permitting movement of the lens or the entire system to lower sun energy is available and there is more con track the sun seasonally or daily. It is preferred that the sumption of energy for heating. lens system for the water distilling apparatus comprise These and other aspects of the present invention will fluid lens means which include said smooth surface and be more apparent from the following description of the in which the solar energy transmitting fluid forming preferred embodiments thereof when considered with part of the lens means is circulated within the collector 65 the accompanying drawings.

means to advantageously utilize the latent heat released BRIEF DESCRIPTION OF THE DRAWINGS by the vapor condensing on said smooth surface and transferred to the water to be distilled. The heat re The present invention is illustrated by way of exam leased by the condensing water is thus not lost and ple and not limitation in the figures of the accompany

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ing drawings in which like numerals refer to like parts water to be distilled comprising two fluid-carrying con and in which: duits, one enclosed in the other; FIG. 1 is a schematic perspective diagram showing a FIG. 16 is a schematic perspective diagram of an system according to the invention comprising an elon other composite system according to the invention for gated fluid lens and a collector comprising two fluid distilling water similar to that of FIG. 15 in which the carrying conduits, one enclosed in the other with the collector comprises a single fluid-carrying conduit and focus of the lens located within the inner conduit; lenses concentrating the solar energy in a single linear FIG. A is a cross-section view of another embodi focus;

ment of the collector of FIG. 1 showing a rectangular FIG. 17 is a schematic perspective diagram of an inner conduit on the upper surface of which is located 10 other system according to the invention for distilling the focus of the lens of FIG. 1; water comprising a single elongated fluid lens and a FIG. 2 is a schematic perspective diagram showing collector comprising a single fluid-carrying conduit; another system according to the invention similar to FIG. 18 is a schematic cross-section diagram of a that of FIG. 1 comprising two radially juxtaposed, elon composite system according to the invention for distill gated fluid lenses in which the focus thereof is located 15 ing water comprising individual systems, each compris within the outer conduit; ing a single, elongated, movable fluid lens to follow the FIG. 3 is a schematic perspective diagram showing seasonal location of the sun and a collector comprising still another system similar to those of FIGS. 1 and 2 a single fluid-carrying conduit in which the individual according to the invention comprising three radially systems are enclosed;

juxtaposed, elongated fluid lenses in which the focus 20 FIG. 19 is a transverse cross-section view of another thereof is located on the upper surface of the outer enclosed system according to the invention for distilling conduit; water also comprising a single, elongated, movable lens FIGS. 4-6 are cross-section views showing different and a collector comprising a single fluid-carrying con configurations of fluid lenses according to the inven duit;

tion; 25 FIG. 20 is a perspective view partly in cross-section FIG. 7 is a perspective view showing a series of lon of the system of FIG. 19;

gitudinally juxtaposed fluid lenses and means for inter FIG. 21 is a transverse cross-section view of another communicating the enclosures of the repsective lenses, enclosed system according to the invention for distilling this arrangement being utilizable to arrange a plurality water also comprising a single, elongated, movable lens of longitudinally juxtaposed lenses where single lens are 30 and a collector comprising a single fluid-carrying con now shown; duit, and having two sliding side panels which form FIG. 8 is a detail perspective of FIG. 7 showing the bags for collecting the condensate;

lens frame; FIG. 22 is a transverse cross-section view of still FIG. 9 is a perspective view of a lens system accord another system according to the invention for distilling ing to the invention comprising two separate plates for 35 water comprising a single, movable elongated, planar enclosing a lens fluid and a frame for sealing the plates Fresnel-type lens having a linear focus and a collector into a fluid-tight lens; comprising a single fluid-carrying conduit; FIG. i0 is a cross-section view of the lens and frame FIG. 23 is a schematic perspective diagram of a por of FIG. 9 taken along line 10-10; table, easily assembled and disassembled system having FIG. 11 is a schematic perspective diagram similar to a fluid lens for distilling water according to the inven that of FIG. 1 showing another system according to the tion;

invention in which the system is enclosed, the single FIG. 24 is a schematic perspective diagram of an lens is movable to follow the seasonal location of the other portable easily assembled and disassembled sys sun and in which the collector comprises a single fluid tem having Fresnel lenses for distilling water according carrying conduit; - 45 to the invention;

FIG. 12 is a plan view of a planar, point-focusing, FIG. 25 is a schematic perspective diagram of still Fresnel-type lens; another portable system having fluid lenses for distilling FIG. 13 is a schematic perspective diagram showing water according to the invention;

another system according to the invention comprising FIGS. 26 and 27 are plan side and front views, respec an elongated, planar Fresnel-type lens having a linear 50 tively, of another system for distilling water according focus and a collector comprising three fluid-carrying to the invention showing means for adjusting the incli conduits in which an outer conduit encloses two inner nation of the fluid lens and for adjusting the horizontal conduits and in which the focus of the lens is located orientation of the entire system. within the outer conduit; FIG. 28 is a cross-section view of a photoelectric cell FIG. 13A is a cross-section view of part of another 55 positioned in a fluid-carrying conduit to produce elec collector comprising three fluid-carrying conduits in tricity from solar energy according to the invention which the innermost conduit is enclosed by the interme with fluid circulating inside and/or outside the conduit diate conduit which is enclosed by the outermost con to remove heat; and duit;

FIG. 14 is a schematic perspective diagram showing to FIG.29 is a perspective view of a collector according the invention comprising apertures for collecting yet another system according to the invention compris solar energy from point focus lenses.

ing an elongated curvilinear Fresnel-type lens and a collector comprising a single rectangular fluid-carrying DESCRIPTION OF THE PREFERRED conduit; EMBODIMENTS

FIG. 15 is a schematic perspective diagram of a com 65 In FIGS. 1-3, are shown solar energy collecting posite system according to the invention for distilling systems according to the invention comprising refrin water comprising individual systems each comprising gent fluid lens concentrators and fluid-containing solar two elongated fluid lenses and a collector located in the energy collectors. Referring to FIG. 1, system 20 is

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shown comprising an elongated fluid lens concentrator boiling point of fluid 56, preferably at least 50° C. less 22 and collector 24 in the form of elongated fluid-con than the boiling point of fluid 56, and preferably in the taining conduits. Elongated fluid lens 22 comprises temperature range of from about -62 C. to about 100 solar energy transmitting plates 26, 28 mounted in frame C. Such a fluid is suitably water. It is also preferred that 30 and spaced to enclose solar energy transmitting fluid fluid 54 have a low latent heat of vaporization, for ex 31. In the emobodiment shown in FIG. 1, upper lens ample, from about 20 calories per kilogram to about 270 plate 26 is convex and lower plate 28 is planar. The calories per kilogram, and such fluids may comprise by respective sides 32, 34 of lens plates 26, 28 and the ends way of example and not limitation freon, butane, pro of the lens plates (not shown in FIG. 1) are sealed to be pane, ammonia, ethyl ether, methyl alcohol, etc. fluid-tight in manners which will be described hereinaf O In operation, solar energy is concentrated in fluid 56 ter. Alternatively, means not shown in FIG. 1 for add (lubricating oil) within conduit 38 and raises the temper ing and removing or circulating fluid 31 and air are ature of the oil to about 200 C. Since the focus to lens provided in the sides and/or ends of the lens plates. 22 is theoretically linear, fluid 56 will be continually Additionally, means also not shown in FIG. 1 for longi heated as it traverses the linear focus. Fluid 54 (water) tudinally and transversely (radially) juxtaposing lenses 15 which surrounds the oil and conduit 38 is heated pri may be provided and will also be described hereinafter. marily by the oil primarily through conduction. Both In the embodiment shown in FIG. , collector 24 com fluids, oil and water, are circulated by fluid circulating prises an outer elongated conduit 36 enclosing an inner means 55, 57 at predetermined rates to obtain desired elongated conduit 38, both shown to be tubular in temperatures and may be used for different heat applica shape. Conduit 36 is placed in insulating container 40 20 tions. For example, the water may be heated to about and is surrounded by insulating material 42 except for a 70 C-80 C. or more and used for space and hot water longitudinally extending opening 44 located above con heating. The water may be heated to lower tempera duit 36. Opening 44 is closed off by solar energy trans tures and used, for example, in swimming pools. The mitting and heat insulating plate 46. Plate 46 is suitably higher temperature oil may be used for applications made of glass or plastic and the insulating material 42 is 25 requiring higher temperatures including industrial ap suitably a foam such as polyethylene foam. Collector 24 plications or may be used merely to heat the water. is located below lens 22 and the theoretical linear focus 48 is located at or along the collector for substantially Sinceverses the temperature of fluid 56 increases as it tra the lens focus, fluids at many different tempera all of the daylight hours. The space between the lens tures are realizable by providing taps for fluid outlet and collector is enclosed by side panels 50 which if rigid 30 and/or inlet at different points along the focus. Fluid 54 can also serve to support lens 22 and frame 30 in cooper may be evaporated and the vapor or superheated vapor ation with support member 52. For optimum concentra used to produce mechanical power in a turbine or en tion of solar energy at collector 24, lens 22 is oriented at gine which, in turn, may generate a preselected angle A with the horizontal, the longitudi bly, a closed system (not shown) is electricity. Prefera nal axis of the lens (and of the system) is oriented along the condensed fluid is returned to collector 24. Inwhich

such the east-west direction and the convex upper lens plate applications, fluids such as freon, butane, propane, ethyl 26 is oriented to face south (northern hemisphere). The ether, methyl alcohol, ammonia and the like may consti optimum value for angle A depends upon the location of the system 20, and for a fixed system is chosen to give tuteAsfluid 54.

mentioned hereinbefore, a serious drawback of optimum concentration on a seasonal basis. For mov solar energy systems in general and known systems in able systems, which will be described hereinafter, angle particular relates to the storage of energy during peri A is selected for optimum seasonal solar energy concen ods in which there is no sunshine or the intensity thereof tration or for optimum concentration for even shorter is low, as for example during the night or during periods periods of time. of cloudy weather. In accordance with the present As mentioned hereinbefore, the collector 24 is lo 45 cated at the theoretical focus 48 of the lens 22 and in the invention, heat is stored for use in those periods in fluid embodiment of FIG. , conduits 36 and 38 are solar 56 which is heated during normal system operation to a energy transmitting, the theoretical focus 48 being lo the temperature which is at least about 50 C. higher than cated within the inner conduit 38. Conduits 36 and temperature of fluid 54. Therefore, even when fluid 38contain heat-carrying fluids 54 and 56, respectively. 50 56 is not being heated by solar energy or being heated at Since the concentration of the solar energy will be aheat reduced rate, it stores heat and will continue to supply greatest in the fluid within the conduit at which the lens tweentothe fluid 54 due to the temperature difference be two fluids. Preferably, the circulation of fluid theoretical focus is located, i.e., in fluid 56 within con duit 38, fluid 56 may be heated to a relatively high 56 is stopped by fluid circulating means 57 for those temperature and is therefore chosen to have a relatively 55 periods. Fluid 56 continues to transfer heat to fluid 54 high boiling point, for example, from about 150 C. to until the difference in the temperature of the two fluids about 350° C. Such fluids may comprise by way of is relatively small. The time that fluid 56 will transfer example and not limitation lubricating oils, glycerine, and/or store heat depends upon the initial temperature olive oil, paraffin oils, etc. Thus, during periods of sun of fluid 56, the difference in temperatures between the shine, fluid 56 is heated to a temperature which may be fluids, the volumes of the fluid, the characteristics (spe in excess of 100' C., for example, 200 C., the precise cific heat, boiling point, latent heat, etc.) of the fluids temperature attained depending on many factors such the use to which fluid 54 is put, etc.

as the flow rate of fluids 54, 56, the diameters of con Further in accordance with the invention, the fluid 31 duits 36, 38 sun intensity and position, insulation, heat in lens 22 may be communicated (not shown) with col exchange rates, etc. Fluid circulating means 55, 57 are 65 lector 24 through conduit 36 or 38 or through another provided to control the circulation of fluids 54, 56 separate conduit to remove heat from the lens fluid, through conduits 36, 38, respectively. Fluid 54 is se thereby maintaining it at a suitable temperature while lected to have a boiling point which is less than the utilizing solar energy absorbed by the lens fluid.

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In FIG. 1, collector 24 was shown to comprise tubu lenses, respectively, it is to be understood that these are lar conduits 36, 38. However, the conduits need not be chosen for purposes of illustration and systems accord tubular and in some instances other configurations are ing to the invention may comprise more than three preferred. For example, referring to FIG. 1A, collector lenses. Conduits 36 and 38 may both include opaque 58 comprises rectangular inner conduit 59. The rectan heat conducting surfaces and the surface of outer con gular configuration may be desirable when the theoreti duit 36 is preferably darkened along the focus to en cal focus varies excessively with seasons and the time of hance heat absorption form the solar energy therealong. day in a single lens system as shown in FIG. 1. Provid The systems shown in FIGS. 2 and 3, of course, have ing a rectangular shape will allow movement of focus the ability to provide greater concentrations to the 48 while still maintaining it at conduit 59. Focus 48 has 10 respective collectors than the system of FIG. 1 because been shown on the surface of conduit 49, and in such a of the increased lens surface area and also to provide a case, the surface of conduit 49 need not be solar energy greater concentration for a longer portion of the day transmitting and is preferably darkened. Fluid 56 inside light hours because of the arrangement of the lenses conduit 59, as in FIG. 1, has a higher boiling point than along radial axes of the collector. outer fluid 54 since the concentration of the solar en 15 In the embodiments shown in FIGS. 1-3, heating is ergy will be at the conduit containing fluid 56. accomplished by heat exchange between fluids 54 and It is to be understood that the systems shown in the 56 without the necessity of an external heat exchanger remaining figures and described hereinafter are longitu which reduces heat losses. Side panels 50 which are dinally oriented in an east-west direction and faced made of an insulating material further reduce heat towards the sun preferably by plus or minus 15' (plus in 20 losses. Additionally, plate 46 provides a greenhouse winter, minus in summer) of the latitude of the location effect in the collectors to further reduce heat losses. in order to achieve an optimum concentration of solar Collector 24 is also preferably made of insulating mate energy, seasonally or for shorter periods of time. It is to rial. The reduction in heat loss is especially important be further understood that the elongated lenses or lens during periods of no or reduced sunshine. It is preferred system and the elongated collectors and conduits 25 that the theoretical focus of the lenses be located at the thereof are arranged substantially along parallel longi inner fluid (FIG. 1) to further reduce heat losses since tudinal axes. Description will be made hereinafter of the outer fluid will act as an insulator. The solar energy movable lens systems for tracking the sun; manual and transmitting tubes in FIGS. 1-3 are preferably made of automatic means for effecting tracking movement of colorless and transparent glass or plastic and the tubes systems and/or lenses on a seasonal basis are known. As 30 which need not transmit solar energy therethrough are mentioned hereinbefore, the refringent lenses according preferably metal, preferably steel, copper or aluminum, to the invention are operative to also concentrate dif and preferably have darkened outer surfaces. fuse solar energy which may represent up to about 40% According to the invention, the area of the collector of the solar energy at the system. While only part of a surfaces may be much smaller than the area of the con single lens is shown in FIG. 1, it is to be understood that 35 centrators and may be only from about 2% to about many lenses may be longitudinally and radially juxta 10% of the area of the concentrators, thus reducing the posed to form systems which will be more fully de heat losses accordingly. As less material is required in scribed hereinafter. Use of many lenses results in a sys the collector, the cost will be reduced. tem with a high degree of solar energy concentration As will be more apparent hereinafter, the collector which is achieved quite economically. systems may comprise a number of conduits other than Referring now to FIG. 2, solar energy collecting two and configurations other than tubular, and the system 60 is shown comprising two transversely juxta lenses and lens systems may be other than those shown posed elongated fluid lenses 22 positioned about a radial in FIGS. i-3 and may be movable and also track the axis of elongated collector 62. System 60 is similar to S.

system 20 and will not, therefore, be described in detail. 45 Referring now to FIGS. 4-10, the fluid lenses accord The system 60 is oriented generally as described herein ing to the invention may have configurations other than before and the lenses and collector are positioned to those shown in FIGS. 1-3. In FIG. 4 is shown planar place the theoretical linear focus 64 of at least one of the convex lens 22 comprising curvilinear upper plate 26 lenses at and along the collector 62 for substantially all and spaced planar lower plate 28 enclosing solar energy of the sun's daily and seasonal locations. Lenses 22 are 50 transmitting fluid 31. The plates may be economically supported by frame members 30 and support members made of glass or plastic and are joined at sides 32, 34 in 52. In the embodiment shown in FIG. 2, focus 64 is a fluid-tight manner as by welding. Alternatively, lens located within conduit 36 which is solar energy trans 26 may be extruded with sides 32, 34 integrally joined. mitting. Thus, higher boiling point fluid 56 is contained The ends of the lenses may similarly be welded or ex in conduit 36 and lower boiling temperature fluid 54 is 55 truded. FIG. 5 shows a bi-convex lens 78 comprising contained in conduit 38 which may include an opaque spaced curvilinear plates 26. Lens 78 is formed as de heat conducting upper surface. The interior of lenses 22 scribed for lens 22. Lens 80 shown in FIG. 6 comprises may be communicated at the sides and or ends thereof curvilinear upper plate 82, spaced planar lower plate 84 (not shown) and means (not shown) may be provided and side walls 86. Lens 80 is economically formed from for adding and removing fluid 31 and/or air. 60 a bulb of glass or plastic as by blowing as, for example, In FIG. 3 is shown solar energy collecting system 70 in the manufacture of glass or plastic bottles. The lenses including a system of three transversely juxtaposed shwon in FIGS. 4-6 when used in collector systems are lenses 22 positioned about a radial axis of collector 72 in supported by suitable frames and structural members. which the linear focus of the lenses is located on the For example, lens 80 is supported by frame 88 shown in surface of conduit 36. Thus, the embodiment shown in 65 FIGS. 7 and 8. As there shown, a plurality of lenses 80 FIG. 3 is similar to that of FIG. 2 except that three are longitudinally juxtaposed at ends 90 and supported lenses are employed and the focus is on the surface of by longitudinal support stringers 92 and transverse sup conduit 36. While FIGS. 2 and 3 show two and three port stringers 94. The lenses may be secured to the

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frame by, for example, adhesives. As shown in FIGS. 7 System 130 of FIG. 13 is shown employing an elon and 8, the theoretical focus 96 of the lenses is at and gated refringent element 132 having longitudinal micro along collector 98. Means in the form of openings 100 prisms 134 acting as a longitudinal Fresnel lens. The are provided to add and remove fluid 31 and/or air and lens 132 and collector 136 are arranged so that the linear the openings may be communicated by, for example, focus is located at collector 136 which is similar to tubes 102 to provide for circulation of the fluid. The collector 24 in FIG. 1 except that two inner conduits openings may be provided in other locations, for exam 138, 140 are enclosed in outer conduit 36. Linear focus ple, as shown in FIGS. 4-7 and referenced by 100. As 142 is located within conduit 36. Providing three con mentioned hereinbefore, the plates forming the lenses duits permits use of three different fluids and allows for may be integrally extruded or blown or may comprise 10 use of the fluids at varying temperatures for many dif. separate plates joined as by welding. Referring now to ferent applications. FIG. 13A shows another arrange FIGS. 9 and 10, upper curvilinear plate 26 and lower ment for three conduits in which the inner conduit 139 planar plate 28 are separate pieces and are joined in a is enclosed by intermediate conduit 141 which in turn is fluid-tight manner by means of frame 104. Frame 104 enclosed by outer conduit 36.

comprises two longitudinal grooves 106, 108. The 15 System 144 in FIG. 14 shows a rectilinear refringent upper groove 106 is curvilinear and sized to accommo element 146 formed with longitudinal microprisms 118 date upper curvilinear plate 26 while the lower groove which direct the solar energy to different linear foci F, F, F2 located at collector 150 depending upon the is linear and sized to accommodate planar plate 28. The seasonal edges of the respective separate plates are inserted into 20 east-westlocation of the sun. Collector 150 is located so it is oriented to collect solar energy during the respective grooves along with sealing material 110. daily movement of the sun, and comprises a single solar The ends of the plates are similarly joined. The material energy transmitting, 110 may comprise a gasket or similar flexible piece lar fluid conduit 154atwhich least at upper part 152, rectangu and/or deformable material such as silicone to form insulating material 42. Partsisofsurrounded in part by fluid-tight joints. Thus, the lenses according to the in 25 shown to proportion. In particular, collectorare150notis system 144 vention in which two independent plates are joined or shown in larger proportion for clarity and is less than the lenses are extruded or blown, are relatively easy to about 10% of the size of lens 146. A closed system is manufacture and are relatively inexpensive.

As mentioned hereinbefore, lens 22 may be movable achieved by extending the sides of refringent element 146 and insulating material 42 into overlapping engage to track the seasonal movement of the sun. In FIG. 11, 30 ment.

system 112 is shown in which the side walls 114,116 are conduitAs154described hereinbefore, use of a rectangular made of expandable plastic whereby the system remains as F, F, F2 facilitates within the location of a moving focus such conduit. Although element 146 enclosed as described hereinbefore upon movement of focuses primarily by refracting the rays of the sun, the lens 22 along a radial axis of the collector. With lens 22 microprisms also provide reflection or rays such as 156. in the positions designated by solid lines, walls 114, 116 35 The inside sides of element 146 may also be suitably assume first positions connected between respective angled and made reflective to reflect any rays imping bottomsides of collector 118 and sides 32, 34 of the lens. ing thereon to the focus.

Upon counter-clockwise rotation of the lens to the posi The present invention may be utilized for many en tion designated by the broken lines, the lengths of the ergy applications as described hereinbefore and may walls are changed and the system remains enclosed. 40 also be advantageously used to distill or otherwise treat Thus, a simple, inexpensive, enclosed system is pro water by evaporation and condensation thereof. Typi vided in which the lens may be moved to track the cally, the water is seawater or brackish water and is to seasonal location of the sun. Still referring to FIG. 11, be desalinated, or water containing minerals or other collector 118 is shown comprising a single tubular inner substances such as industrial waste water or polluted conduit in which the focus 120 is located. 45 water which is to be purified and distilled. Further in Description of preferred embodiments of the inven accordance with the invention, the refringent concen tion has been made hereinbefore with reference to linear trators and collectors according to the invention are theoretical focus fluid lenses. However, in accordance arranged in systems operative to distill water, prefera with the invention, the solar energy may be concen bly recovering the heat of condensation as described trated by focal point lenses and by solid lenses. In FIG. 50 hereinafter. Preferred embodiments of such systems are 12 is shown a plane refringent element 126 comprising a shown in FIGS, 15-27.

rigid frame 128 surrounding asheet or plate of plastic or The system 160 shown in FIG. 15 comprises a plural glass material 130 in which are formed by impressions ity of sub-systems 162, each employing a two lens ar or molding concentric closely spaced rings or micro rangement 164 as shown in FIG. 2. Each lens pair 164 is prisms 32 whose pitch, for example, corresponds to 55 supported in a manner similar to that described for FIG. about 3 to about 6 microprisms per millimeter. The 2 above an elongated, central, rectangularly configured plane refringent element 126 acts like a plane Fresnel channel 166 and parallel, elongated, rectangularly con lens. Solar energy striking the refringent element 126 is figured, side channels 168 such that the central part of concentrated by the microprisms into a theoretical the pair of lenses is above the central channels and the point focus (not shown). Refringent elements 126 may outer longitudinal edges of the lenses are above the side be positioned longitudianlly juxtaposed as the fluid channels. Each individual lens is inclined and addition lenses in FIG. 7 and/or radially juxtaposed as the fluids ally the pair of lenses is rotated slightly in a clockwise lenses in FIGS. 2-3. The system may be arranged so direction such that adjacent pairs are overlapping. The that the point foci of lenses 126 are located within or at bottom lens plates 28 are planar. The water 170 to be the surface of conduits 36, 38, 59 as described hereinbe 65 distilled is filled in the central channel to a predeter fore, the series of discrete point foci along a length mined height. Within channel 166 is positioned collec forming, in effect, a linear focus composed of discrete tor 172 which comprises conduits 36, 38 as in FIGS. point foci. 1-3. The focus 64 of the lens pair 164 is located within

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inner conduit 38. Preferably, the interior of lenses 22 is In FIG. 16 is shown another embodiment (system communicated with collector 172. In the embodiment 186) for treating water 170 employing a three lens ar shown in FIG. 15, lens fluid 31 is advantageously water rangement (and a correspondingly larger area of evapo and the interior of the lenses is communicated by con ration) such as the one shown in FIG.3 and a collector duit 174 with outer conduit 36 in which the fluid is also comprising single conduit 188. Lenses 22 are supported water. The fluid in the inner conduit 38 is a higher generally as described for FIG. 15 above central chan boiling point fluid as described hereinbefore. In opera nels 190 and side channels 192 shown to be semicylin tion, the water 170 to be distilled is heated by collector drical. System 186 operates similar to the system shown 172 due to the solar energy concentrated thereat and the in FIG. 15. However, in FIG. 16 only a single conduit water 170 is vaporized. The vapor strikes the lower 10 and fluid are used as the heating medium. Advanta plates 28, is condensed thereon and flows therealong to geously, the central channels are made of concrete and be discharged at or dropped from the edges thereof into the side channels of asbestos cement. side channel 168. In accordance with the invention, the In FIG. 17, a single lens system, single conduit system water in the fluid lenses is circulated through collector 5 196 is shown which is similar to those described herein 172. In this way, the heat released by condensation of before. The adjacent channels 198, 200 for the water the vapor is transmitted through the plate 28 to the 170 to be distilled and the distilled water, respectively, water in the lenses and the heat absorbed by the water are trough-shaped and may advantageously be formed in the lens from the condensing vapor is returned to the from adjacent plates. The inclined lens 22 is above chan system through conduit 36. This is significant because nels 198, 200 and the lower part of lens 202 terminates the latent heat required to vaporize the water 170 of 20 above channel 200 to permit the condensed water to fall about 539 calories per liter (975 BTU per kilogram) in therein.

addition to the sensible heat is substantially returned to In FIGS. 18-21 are shown systems of the single lens, the system by the circulated water in the lenses upon single conduit type described hereinbefore which are maintained essentially enclosed while lenses 22 are which the vapor condenses. This latent heat is substan 25 moved tial and would otherwise be lost. This results in a much to track the sun. In FIG. 18, an expandable higher efficiency of the system compared with solar 206, material, as described for FIG. 11, forms the side panels stills where channels filled with water to be treated are 208 of each compartment 210 of the system. Ad covered with only glass plates which receive the solar 212, vantageously, the material is of plastic. Opposed ends 214 of adjacent side walls 208,206 are secured to rays. Circulating the water in the lenses also cools the respective lower lens plates 28 thereby assisting condensation 30 walls sides of lenses 22. Adjacent interior side are thereon. Conduits 175 and 176 are provided for filling a single sheet of one piece and are advantageously formed as and emptying the respective channels. The water 170 to the circumference 216. Sheet 216 is wound partially about be distilled may be held between predetermined heights tend along longitudinal of tubular members 218 which ex by a float system comprising float 178 and relays 180 35 channels 220, 222. The tubularaxes parallel to those of the and 182. Movement of the float activates respective means (not shown) to maintainmembers are secured by relays to start and stop a pump or motor valve (not 208, 206 as shown. The lower sides 210 asof side

lenses 22 shown). A similar arrangement may be used in side terminate above channels 222. The evaporation and channels 168 or a gravitational drain arrangement may condensation of the water proceeds as described herein be employed to maintain the height of distilled water in before. In addition to enclosing the system, condensed the side channels between predetermined heights. The water flows down side panel 208; and side panels 206, respective channels are communicated to provide ap 208, when cooled by the outside environment, will proximately equal levels in each of the respective chan provide additional condensation nels. Advantageously, the channels are made of con flow down panel 206 as well. Theofsystem vapor which will remains en crete or asbestos cement. Means other than the lens 45 closed upon movement of the lens as follows. If the itself may be used to condense the vapor such as sub lenses are rotated counterclockwise, interior side panels stantially smooth preferably planar plates located below 206 move downwardly and interior side panels 208 the lenses 164. In such a case, the lens fluid may not move upwardly about tubular members 218. The exte recover the latent heat unless the plate is proximate rior side panels 206a and 208a are secured to the sides of thereto. Alternatively, means associated with the plate 50 respective channels 222 and are made of an expandable may be used to recover the latent heat. material as described in FIG. 11. The system shown in FIG. 15 is substantially en In FIFGS. 19 and 20, another system 223 is shown for closed by the channel panels to reduce heat loss as treating water in which the lens 22 is movable and the described hereinbefore. The two-conduit collector 172 system maintained enclosed. A central elongated trough is particularly advantageous since the fluid in the inner 55 224 holding water 170 to be treated is placed above conduit 38 may be raised to a high temperature and used elongated semi-cylindrical member 226 along parallel to store heat as described hereinbefore. This adds a very longitudinal axes. Member 226 is formed from sheet important capability to the system in that it can operate material 228 which is secured at opposed ends thereof during the night and during periods of reduced sun 230, 232 to respective sides 32, 34 of lens 22. Sheet 228 shine. This is very important in that it provides the extends from one end 230 thereof at lens side 32 down advantage of substantially continuous operation result wardly between longitudinal tubular members 234 to ing in increased system output at reduced cost. The form side wall 236, then downwardly below trough 224 recovery of the latent heat of the condensing vapor by and upwardly between longitudinal tubular members the lens fluid assists in providing a continuous operation 238 to form channel 226, then upwardly to terminate at system since heat loses are reduced. The water distilla 65 end 232 at lens side 34 and form side wall 240. Thus, tion systems described hereinafter operate in similar system 226 is enclosed by a single sheet member. The manner and description thereof will therefore be more tubular members permit the sheet to slide therebetween limited. and maintain the width of channel 226. When lens 22 is

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rotated clockwise, side wall 240 moves downwardly from by means such as valve 317 in outlet 318. Port 320 and side wall 236 upwardly. Point 242 moves down is provided in vessel 306 for filling and emptying. Con wardly to become the bottom of the channel as refer duit 312 is advantageously collapsible and made of enced by 244 while the point previously at the bottom lightweight plastic and is solar energy transmitting, the moves upwardly to be at point 244a. 5 theoretical linear focus of lens 282 being located within In FIG. 2E is shown still another system 246 which is conduit 312. Distillation of water 170 by heating of the maintained enclosed upon movement of the lens. In fluid in conduit 312, advantageously water, and evapo system 246, the side panels 248,250 are secured at op ration of the water, condensation of the vapor on the posed ends to lens sides 32, 34 and to opposed sides 252, lens and collecting of the condensate proceed as de 254 of central trough 256. The side panels 248,250 are 10 scribed hereinbefore. Expandable side panels 320 may passed between tubular members 234, 236 in a manner be provided to enclose the system and allow for move similar to that shown in FIG. 21 to form outer channels, ment of lens 282 as described hereinbefore and may be 258 one of which is below lower sides 32 of lens 22. used to form collecting bags as shown in FIGS. 19-22. Movement of the lenses 22 in a counterclockwise direc Means are provided to indicate the water levels in the tion causes side wall 250 to move upwardly reducing 15 vessels 306, 314 such as vertical transparent glass or the size of channel 258 and side panel 248 to move plastic tubes 322,324 located outside side panels 320 and downwardly increasing the size of channel 256. connected by tubing with the bottoms of the vessels. In FIG. 22 is shown a single lens, single conduit sys In FIG. 24 is shown another embodiment of a porta tem 260 employing an elongated, planar Fresnel-type ble water distillation system 330 which is easily assem lens 132 in which the side walls 262, 264 are made of 20 bled and disassembled. System 330 comprises planar expandable material. Lens 132 is supported by solar Fresnel lenses 126 of the type shown in FIG. 12 having energy transmitting glass or plastic support 266 and concentric microprisms causing the solar energy to be inclined with the central part of the lens above elon concentrated at point foci. Lenses 126 are longitudinally gated central channel 268 containing the water 170 to and transversely juxtaposed to form a composite lens be distilled and with lower part 272 above elongated 25 assembly of six Fresnel lenses which is inclined with side channel 270. Vaporization and condensation pro respect to the horizontal, six being chosen for purposes ceed similar to that described for FIG. 18. System 260 is of illustration. The lenses are formed into an assembly maintained enclosed upon movement of lens 132 by by, for example, securing them as by adhesives to a solar stretching and shrinking of side panel 262, 266 as de energy transmitting glass or plastic plate 332 which, in scribed for FIG. 11, opposed ends of the side walls 30 the case of plastic, may be folded along flexible partition being secured to respective sides of the lens and to lines 334. Each Fresnel lens may be about 9 inches by respective parts of channels 270. about 7 inches and are presently available at a cost of Referring now to FIG. 23, a portable water distilla about $0.40 each. The point foci of the lenses are lo tion system 280 is shown comprising elongated fluid cated in the water to be distilled in flexible container or lens 282 and single conduit collector 284. The system is 35 bag 336 made of plastic or other plyable material. Flexi easily assembled and disassembled. Lens 282 is made of ble container or bag 338 made of plastic or other flexible flexible solar energy transmitting material such as clear material located below and extending beyond container plastic and forms an enclosure 286 when inflated by a 336 is used to collect condensate from plate 332. The fluid, advantageously water, which is introduced and lens assembly and containers are supported by support removed and/or circulated by means including inlet 288 40 assembly 340 comprising pairs of legs 342, 344, frame and outlet 290. Air is also removed and introduced 346 and platform 348. The legs are pivotably connected through said means. Lens 280 is supported by frame 292 to frame 346 as described for FIG. 23 to adjust the angle of metal or other suitable material which comprises of incline of the lens assembly to follow the seasonal upper frame members 294 and side support members location of the sun. The containers or bags have side 296. The upper ends 297 of the side support members 45 panels 350, 352 which extend upwards to plates 332 to 296 are pivotably connected to the upper frame mem form an enclosed system as described hereinbefore. An bers 294 as by bolts 298 such that each of the side sup opening is provided in side panel 352 at the lower side port members is pivotable about the bolts in the direc of plate 332 to allow the condensate to drop into the tions indicated by the arrows. Means such as indenta collector bag 338. Means such as transparent tubes 322, tions 300 are provided in platform 302 to secure the 50 324 connected to the bottom of the containers are used lower ends 304 of the side members in selected posi to indicate water levels therein as described for FIG. 23. tions. Alternatively, a platform is not used and ends 304 The lens assembly, support assembly and containers are may be secured in the ground or otherwise. Pivoting of easily assembled and disassembled. The foci located in side members 296 adjusts angle A at which lens 282 is the water to be distilled in container 336 heat the water included for reasons which were described hereinbefore 55 and cause it to evaporate, condensing on the bottom of with respect to FIG.1. An elongated vessel 306 advan planar plates 332. The condensate moves along plates tageously collapsible and made of lightweight plastic is 332 and falls into container 338. Depending upon loca hung from frame members 294 below the central part of tion, production of distilled water will be about 1 pound elongated lens 282 by cables or rope 308. Hinges 310 are per hour for a system as shown in FIG. 24 having a lens provided to secure the cables to the vessel. Vessel 306 60 surface area of 10 square feet (about 1 square meter). contains the water 170 to be distilled and conduit 312 is This production of distilled water is without recovering disposed within the water. A collecting vessel 314 is the latent heat of condensation. Production of distilled located below vessel 306 and below the lower inclined water could be about six times larger if the latent heat of end 316 of lens 288. Vessel 314 advantageously collaps condensation is recovered. As mentioned hereinbefore, ible and made of lightweight plastic is also hung from 65 portable systems can be used at sea or in desert areas. upper frame members by cables or ropes 308 and hinges Still another portable distillation system 356 is shown 310. Vessel 314 is inclined preferably along the longitu in FIG. 25. Lens assembly 358 comprises longitudinally dinal direction to assist in draining treated water there juxtaposed, linear focus, fluid lenses 360 mounted in

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frame 362. Lenses 360 and lens frame 362 are similar to retical focus 402 is linear or transparent apertures may those described with respect to FIGS. 6-8, the lenses be provided above the cells if the theoretical focus 402 being blown and filled with liquid. The lens assembly is is at a point. The upper part of outer conduit 408 is also supported by pairs of legs 364, 366 which are pivotably transparent. The details of inner and outer conduits connected to frame 358 to change the angle of inclina have been descibed hereinbefore. tion of the lens assembly to follow the seasonal location As mentioned hereinbefore, in accordance with the of the sun. Container 368 for the water to be distilled invention, concentrating the luminous energy of the sun and container 370 for the condensate are supported by with a concentration of up to about 100 permits electric frame 360 by cables or rope 308. ity to be generated at up to about 100 times more power Referring now to FIGS. 26 and 27, another distilla 10 while the increased heat energy is dissipated and re tion system 370 is shown. Lens assembly 372 is sup moved by the fluids in the conduits. Electricity may be ported on frame 374 which in turn is pivotably sup generated in conjunction with other uses of solar en ported by U-shaped support member 376. Threaded ergy. For example, referring to FIGS. 1-3, using a dual studs 378 extend from the frame through the support fluid carrying collector, photoelectric cells may be member and threaded knobs or nuts 380 lock the lens 15 inserted therein as just described and electricity gener assembly in position. Member 376 is secured in base 382. ated while the heat energy is being used to heat a struc Containers 384, 386 are supported from frame 374 by ture.

cables or ropes 308. Side panels 388 are provided to An arrangement for using a point focus lens is shown enclose the system and are movable with respect to in FIG. 29. The theoretical focus is at opening 410 in rollers 390. Water to be distilled is added to container 20 fluid-carrying conduit 412 which is made of solar en 384 by tube 392 and distilled water is removed from ergy transmitting material. If desired, a photoelectric container 386 by spigot 394. The angle of incline of lens cell may be located in opening 410. An insulating mate assembly 372 is changed to follow the seasonal location rial 414 surrounds conduit 412 except at openings 410. of the sun by loosening threaded knobs or nuts 380 to A point focus fluid lens is referenced by 416. unlock the lens assembly, rotating the lens assembly to 25 a new position, and tightening the knobs to lock the lens CONCLUSION assembly. Pivoting of the lens does not move the con Prominent aspects and advantages of the invention tainers. However, rollers 390 permit movement of the may be summarized as follows:

lens assembly with respect to the side panels 388 so that A lens concentration system is combined with a con the system remains enclosed. The lens assembly and 30 duit collector system in which the surface area of the containers are manually rotatable about base 382 as a concentrating system exposed to the sun is from about unit to further follow the location of the sun as follows. 10 to about 100 times larger than the surface area of the A threaded shaft 396 is rigidly secured to the lower part collecting system through which the energy is concen of the assembly, and base 382 comprises a threaded trated. As a result heat losses are reduced substantially portion to accept the threaded shaft. This threaded 35 since the collector has an area of, for example, only arrangement between the base and the shaft with the from about 1% to about 10% of conventional flat plate support member connected thereto permit rotation of collector systems and the overall surface area is about the shaft and support member about the base. If desired, half that of conventional flat plate systems. Thus, the non-manual means such as motors can be used to rotate efficiency over conventional flat plate systems is in the the system and/or to pivot the lens assembly. order of about 50% higher. This reduction in surface According to another aspect of the invention, the area reduces correspondingly the material requirements concentrated solar energy is used to generate electricity per unit of surface area exposed to the sun and the in by means of photoelectric cells. More particularly, the vestment cost is also reduced correspondingly by about luminous rays of the sun are concentrated on photovol one-half.

taic cells. Referring to FIG. 28, photovoltaic cells 398 45 More solar energy can be collected by the method made of silicon or cadmium or other materials are dis and apparatus according to the invention since the col posed in the interior of inner fluid-carrying conduit 400 lector conduits are oriented east-west thereby being shown advantageously to be of rectangular crosssec located at the foci of the lenses throughout the day and, tion. The theoretical focus 402 of the lens is at the cells according to the invention, the lenses can be moved and and preferably on the outer surface thereof. The cells 50 positioned at various inclinations to optimally follow may be juxtaposed if the theoretical focus 402 is linear the seasonable location of the sun. This positioning of or spaced if the theoretical focus 402 is a point focus. the lenses can represent up to 40% higher solar energy The concentrated luminous rays are converted to elec collection. Even using auxiliary equipment to adjust the tricity by the cells while the heat absorbed by the cells inclination of the lenses, the reduction in investment is from the infrared rays is removed by the circulating 55 in the order of a third over flat panel systems. Not only fluid 404 and also by the fluid 406 circulating within the is the investment cost much less than known solar sys outer conduit 408. The removal of heat can be con tems, but the operating cost of obtaining heat energy is trolled by the size of the conduits 402, 406 and by the lower. Also the cost of heat derived from solar energy volume and rate at which the fluid are ciculated. Prefer according to the invention is lower and may be up to ably fluid 404 is substantially electrically non-conduc 60 one-third lower than the cost of petroleum fuels based tive such as air or other gases and liquids. Means (not on the usable heat content. This is of great importance shown) are provided for connecting the cells in parallel to oil importing countries. Additionally, solar energy is or series and for removing the generated electricity. If inexhaustable and does not produce pollution as does fluid 404 is electrically conducting, means (not shown) the burning of other fuels.

are provided for electrically insulating the cells and the 65 According to the invention, by concentrating the means for interconnecting the cells and for removing solar energy at elongated conduits, higher tempera the generated electricity. Conduit 402 has at least its tures, for example, exceeding 200° C. (392 F) are at upper surface made of transparent material if the theo tainable using high boiling temperature fluids in the

Page 22

conduits such as lubricating oil, glycerine, etc. This is to cording to the invention could be used for air condition be compared with to about 80°C. (176 F.) attainable by ing and, as just mentioned, in refrigeration systems. flat plate systems. According to the invention, multiple Also, the multi-conduit collectors and fluids are capable conduits, either conduit receiving the foci of the lenses, of providing temperatures of about 70° C. to about 80 allows storing solar heat to be used for hours without C. for heating rooms and for heating water, and at sunshine. The invention provides for storage of heated higher temperatures, for example, about 180 C. to fluids in the inner conduit at high temperature, for ex about 200 C., for heat storage applications and to pro ample, over 200° C. which heats the outside fluid to duce electricity.

lower temperatures, for example, 80° C. Using this ar The apparatus according to the invention has been rangement permits a reduction in storage volume re 10 described primarily using schematic diagrams. Accord quired by the higher temperature fluid over fluids at ingly, certain details not essential to an understanding of about 80 C. According to the invention, low boiling the invention have been omitted. For example, the ma point and low latent heat of vaporization fluids such as terials and support structure comprising the apparatus freon, ether, etc. are used in the conduits which fluids according to the invention not described in detail will are vaporized and superheated by the solar energy and 15 be known to those skilled in the respective arts. The used to produce electricity in expansion motors such as sizes of the parts of the apparatus described hereinbe turbines at lower cost than using fuel. fore will vary depending on the use to which the appa Electricity may also be produced according to the ratus is put. For example, the lenses in FIG.3 may each invention with photovoltaic cells where the increased be 60 inches wide for a total radial width of 180 inches solar energy concentration of up to 100 times increases 20 for three lenses. The conduit in a single conduit collec substantially the electric production and correspond tor may be a tube 2 inches in diameter wherein the ingly reduces the cost of electricity. Several circulating concentration of the lenses on the tube is in the order of fluids in several conduits are employed to remove the 90. In a two conduit collector system, where the inner heat developed by the concentrated infrared solar rays. fluid is lubricating oil heated to about 200 C., the space Employing several fluids according to the invention 25 required to store an equal amount of heat will be about permits simultaneous use for many purposes such as 2 times less than for a fluid such as water heated to 80' heating water, heating buildings, air conditioning, pro C. Also, the multiple conduit system permits multiple ducing electricity, etc. uses for the heats of the different fluids. For example, a An advantage of the present invention over reflecting fluid heated to about 200 C. may be used to heat build systems is that diffuse sun energy of up to about 40% 30 ings and a fluid heated to about 70° C. to 80 C. may be can be collected. Reflecting systems generally require used for heating water. As shown in FIGS. 2, 3, 7, 8, 15, costly tracking equipment to follow the location of the 16, 18, many fluid lens may be radially and longitudi sun and such reflective systems are more expensive for nally juxtaposed to form composite systems from indi this and other reasons including maintenance of the vidual systems or very large systems. The Fresnel-type reflective surfaces. 35 lenses may have similar length and width dimensions Further according to the invention water containing and may be similarly employed in composite or large salt or other substances is distilled using solar energy systems. Portable distillation units may be used, for collection and concentration according to the invention example, as mentioned hereinbefore, in lifeboats to dis and recovering a large part of the latent heat of vapori till sea water or in desert areas to distill brackish water zation and sensible heat (about 1100 BTU/lb or 600 and thereby possibly save lives. Portable units accord cal/kg). This is accomplished by using the fluid circu ing to the invention could produce, for example, one lating in the lens system to recover the latent heat and pound of distilled water for every square meter (about circulating the fluid in the conduit in the water to be 10 square feet) of lens concentrator area exposed to the distilled thereby heating the water to be distilled. The sun's rays, and this without recapturing the heat of salt from the concentrated brine may also be recovered 45 condensation. The production of distilled water, how and sold or electrolyzed. Distillation according to the ever, will be about six times as great if the heat of con invention is at low cost such that water may be pro densation is recovered.

duced for irrigation purposes. The invention provides It is pointed out that the heat obtained from the sun for portable dismountable distillation units which could using the energy systems according to the invention be used to distill sea water in lifeboats or brackish water 50 may be lower in cost than heat energy obtained from in arid desert areas thereby possibly saving lives. fuels which may thus be replaced. Heat storage pro While specific applications of the invention have been vided by systems according to the invention is a feature described, many are uses of the collected solar energy which also makes these systems competitive with fuels. are possible. For example, the salt by-product of desali The distillation systems according to the invention are nation may be collected and sold to reduce the over-all 55 capable of providing distilled water at low cost and operating cost of the system. Additionally, the salt may therefore are important where clean water is scarce. be separated into sodium and chlorine by electrolysis by The advantages of the present invention, as well as electricity generated by the solar energy collecting certain changes and modifications of the disclosed em system. In this respect, water can be separated into bodiments thereof, will be readily apparent to those hydrogen and oxygen also by electrolysis, the hydrogen 60 skilled in the art. It is the applicant's intention to cover of which in turn may be used in the manufacture of by their claims all those changes and modifications liquid methanol which is easily transported and may be which could be made to the embodiments of the inven used as fuel for automobiles, airplanes, etc. The system tion herein chosen for the purposes of the disclosure described hereinbefore could be combined with known without departing from the spirit and scope of the in heat pumps to further utilize the collected solar energy 65 vention.

in combination with the heat provided by the heat What is claimed is:

pumps, particularly for refrigeration systems. In addi 1. Apparatus for collecting solar energy comprising tion to providing energy for heating, the systems ac collector means including at least two elongated con

Page 23

duits for passing fluids therethrough and at least two 17. The apparatus of claim 10, wherein the fluid hav different fluids, said conduits having substantially paral ing the lower boiling point has a low latent heat of lel axes and being disposed so that an inner first of said vaporization.

conduits containing one of the different fluids therein is 18. The apparatus of claim 17, wherein said low heat enclosed by an outermost conduit containing another 5 of vaporization if from about 20 calories per kilogram to fluid therein with the fluids in said inner and outermost about 270 calories per kilogram.

conduits being in a heat exchanging relationship, said 19. The apparatus of claim 10, wherein the fluid hav inner and outermost conduits being transparent at least ing the lower boiling point comprises at least one fluid in part, said apparatus further comprising elongated lens selected from the group consisting of water, Freon, means having an axis extending substantially parallel to O butane, propane, ethyl ether, ammonia and methyl alco said axes of said conduits and being disposed to concen hol.

trate solar energy through transparent portions of said 20. The apparatus of claim 18, wherein the fluid hav inner and outermost conduits to an elongated focus ing the lower boiling point comprises at least one fluid located substantially on or within and substantially 15 selected from the group consisting of Freon, butane, along the length of said inner conduit. propane, ethyl ether, ammonia and methyl alcohol. 2. The apparatus of claim 1, wherein said lens means 21. The apparatus of claim 1, and comprising means comprises a plurality of longitudinally disposed point for circulating said fluids through said inner and outer focus lenses for concentrating the solar energy in sub most conduits and for controlling the circulation of said stantially discrete points. 20 fluids and for selectively stopping the circulation of at 3. The apparatus of claim 1, wherein said lens means least one of said fluids in its respective conduit. include at least one fluid lens which comprises a solar 22. The apparatus of claim 1, and further comprising energy transmitting lens fluid and spaced, solar energy insulating means for insulating said apparatus against transmitting lens plates enclosing said lens fluid, said heat loss to its environment.

lens fluid and said lens plates being selected to transmit 25 23. The apparatus of claim 1, and further comprising therethrough substantially undiminished the infrared means for moving said lens means for maintaining said solar energy. focus substantially on or within and substantially along 4. The apparatus of claim 3 and further comprising said length to track the sun's position.

means for connecting said fluid lens with one of said 24. An elongated collector for converting concen inner and outermost conduits for transmitting said solar 30 trated solar energy into heatenergy comprising an elon energy transmitting fluid between said lens and one of gated container including at least two elongated con said inner and outermost conduits. duits for passing fluids therethrough, said conduits and 5. The apparatus of claim 1, wherein said lens means container having substantially parallel axes, said con comprises at least one Fresnel lens. tainer having an elongated opening having an axis sub 6. The apparatus of claim 1, wherein said lens means 35 stantially parallel to that of the container, said conduits comprises a plurality of lenses positioned along the axis being disposed so that an inner first of said conduits of said lens means. containing one of the different fluids therein is enclosed 7. The apparatus of claim 1, wherein said lens means thereinby an outermost conduit containing another fluid comprises a plurality of lenses positioned along an arcu with the fluids in said inner and outermost con ate axis transverse to the axis of said lens means. 40 duits being in a heat exchanging relationship, said inner 8. The apparatus of claim 1, wherein said inner and part, and outermost conduits being transparent at least in outermost conduits are substantially tubular. said container including said elongated opening and transparent 9. The apparatus of claim 1, wherein at least one of conduits being aligned portions of said inner and outermost said inner and outermost conduits is rectangular at least 45 through said opening to permit passage of solar energy in part. and transparent portions, whereby an elongated focus 10. The apparatus of claim 1, wherein the fluid within ergy may be located substantially of concentrated solar en said inner conduit has a higher boiling point than the substantially on or within and fluid in said outermost conduit. along the length of said inner conduit. 25. The collector of claim 24, and further comprising 11. The apparatus of claim 10, wherein the boiling 50 insulating points of said two fluids are separated by more than 50 heat loss tomeans for insulating said collector against its environment.

12. The apparatus of claim 10, wherein the fluid hav 26. The collector of claim 24, wherein said collector ing the higher boiling point has a boiling point in excess further comprises solar energy transmitting means en of about 150 C. closing at least part of said collector and permitting 55 concentration of the solar energy on or within said 13. The apparatus of claim 12, wherein the fluid hav ing the higher boiling point has a boiling point less than inner conduit and inhibiting loss of heat from said col lector.

about 350 C. 27. The collector of claim 24 wherein the fluid within 14. The apparatus of claim 10, wherein the fluid hav said inner conduit has a boiling point at least about 50 ing the higher boiling point comprises at least one fluid C. higher than the boiling point of the fluid in said out selected from the group consisting of lubricating oils, ermost conduit.

glycerine, olive oils, and paraffin oils. 28. The collector of claim 27, wherein the fluid hav 15. The apparatus of claim 10, wherein the fluid hav ing the higher boiling point has a boiling point of from ing the lower boiling point has a boiling point not about 150 C. to about 350° C.

greater than about 100 C. 65 29. The collector of claim 27, wherein the fluid hav 16. The apparatus of claim 15, wherein the fluid hav ing the higher boiling point comprises at least one fluid ing the lower boiling point has a boiling point in excess selected from the group consisting of lubricating oils, of about -62 C. glycerine, olive oils, and paraffin oils.

Page 24

30. The collector of claim 27, wherein the fluid hav tion of said outermost conduit to an elongated focus ing the lower boiling point has a boiling point of from located substantially on and substantially along the about -62 C. to about 100 C. length of said inner conduit. 31. The collector of claim 27, wherein the fluid hav 43. The apparatus of claim 42, wherein said inner ing the lower boiling point has a low latent heat of 5 conduit is transparent at least in part, the elongated vaporization of from about 20 calories per kilogram to focus passing through a transparent portion of said about 270 calories per kilogram. inner conduit and being located substantially within and 32. The collector of claim 27, wherein the fluid hav substantially along the length of said inner conduit. ing the lower boiling point comprises at least one fluid 44. The apparatus of claim 42, wherein said first liq selected from the group consisting of water, Freon, 10 uid has a higher boiling point than said second liquid. butane propane, ethyl ether, ammonia and methyl alco 45. The apparatus of claim 42, wherein said first liq hol. uid has a boiling point of greater than about 150° C. and 33. The collector of claim 32, wherein the fluid hav said second liquid has a boiling point of less than about ing the lower boiling point comprises at least one fluid 100 C.

selected from the group consisting of Freon, butane, 15 46. The apparatus of claim 42 and including means for propane, ethyl ether, ammonia and methyl alcohol. circulating said liquids and for controlling the circula 34. The collector of claim 24 and including means for tion of said liquids and for selectively stopping the flow circulating said fluids and for controlling the circulation of said fluids and for selectively stopping the flow of at of at least one of said first and second liquids in said inner and outermost conduits.

least one of said fluids in said inner and outermost con 20 47. An elongated collector for converting concen duits.

35. A method for collecting solar energy comprising trated gated solar energy into heatenergy comprising an elon container including at least two elongated con concentrating solar energy in a narrow elongated focus duits for passing liquids therethrough and at least two and locating said focus on or within and substantially along the length of a first elongated conduit which is 25 different liquids, said conduits and container having substantially parallel axes, said container having an transparent at least in part, contains a first fluid therein elongated opening having an axis substantially parallel and is enclosed by a second elongated circuit which is to that of the container, said conduits being disposed so also transparent at least in part and contains a second different fluid therein, the axes of the conduits and the that an inner first of said conduits containing a first focus being substantially parallel, the method including 30 liquid is enclosed by an outermost conduit which is the steps of placing the two fluids in a heat exchanging transparent at least in part and contains a second liquid relationship, selectively circulating the fluids through therein,in the liquids in said inner and outermost conduits the conduits and concentrating the solar energy being a heat exchanging relationship, said container through the transparent portions of the conduits to said including said elongated opening and transparent por focus. 35 tion of said outermost conduit being aligned to permit 36. The method of claim35, wherein the boiling point passage parent of solar energy through said opening and trans portion, whereby an elongated focus of concen of said first fluid is at least about 50 C. greater than that trated solar energy may be located substantially on and of said second fluid.

37. The method of claim 36, wherein said first fluid is substantially along the length of said inner conduit. permitted to rise in temperature to be at least about 50 48. The apparatus of claim 47, wherein said inner C. above the temperature of said second fluid and heat conduit is transparent at least in part with a transparent is selectively transferred from said first fluid to said portion thereof being aligned with said transparent por second fluid. tion of said outermost conduit and said opening, 38. The method of claim 37, wherein the rate of circu whereby the elonged focus may be located substantially lation of said first fluid is selectively controlled to trans 45 within and substantially along the length of said inner conduit.

fer heat to said second fluid.

39. The method of claim 36, wherein that said focus is 49. The collector of claim 47, wherein said first liquid located within said first fluid and said first fluid has a has a higher boiling point than said second liquid. boiling point of from about 150 C. to about 350 C. 50. The collector of claim 47, wherein said first liquid 40. The method of claim 39, wherein the boiling point 50 has a boiling point of greater than about 150 C. and said of said second fluid is from about -62 C. to about 100 second liquid has a boiling point of less than about 100' C. C.

41. The method of claim 40, wherein said second fluid 51. The collector of claim 47 and including means for has a low latent heat of vaporization of from about 20 to circulating said liquids and for controlling the circula about 270 cal/kg. 55 tion of said liquids and for selectively stopping the flow 42. Apparatus for collecting solar energy comprising of at least one of said first and second liquids in said collector means including at least two elongated con inner and outermost conduits.

duits for passing liquids therethrough and at least two 52. A method for collecting solar energy comprising different liquids, said conduits having substantially par concentrating solar energy in a narrow elongated focus allel axes and being disposed so that an inner first of said and locating the focus on and substantially along the conduits containing a first liquid is enclosed by an outer length of a first elongated conduit containing a first most conduit which is transparent at least in part and liquid therein enclosed by a second elongated conduit contains a second liquid therein, the liquids in said inner which is transparent at least in part and contains a sec and outermost conduits being in a heat exchanging ond different liquid therein, the axes of the conduits and relationship, the apparatus further comprising elon 65 the focus being substantially parallel, the method in gated lens means having an axis extending substantially cluding the steps of placing the liquids in a heat ex parallel to the axes of said conduits and being disposed changing relationship, selectively circulating the liquids to concentrate solar energy through a transparent por through the conduits and concentrating the solar en

Page 25

ergy through a transparent portion of the second con 55. The method of claim 52, wherein said first liquid duit to said focus. has a boiling point greater than about 150 C. and said 53. The method of claim 52, wherein the inner con second liquid has a boiling point of less than about 100 duit is transparent at least in part and the elongated C.

focus is passed through a transparent portion of the 56. The method of claim 52 and including the steps of inner conduit and located substantially within and sub regulating the flow of liquid in the inner and outermost stantially along the length thereof. conduits and selectively stopping the flow of liquid in at 54. The method of claim 52, wherein said first liquid least one of the inner and outermost conduits. has a higher boiling point than said second liquid.

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UNITED STATES PATENT AND TRADEMARK OFFICE

CERTIFICATE OF CORRECTION

INVENTOR(S) : Virgil Stark et al.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby Corrected as shown below:

Column 2, line 43, change "less" to --lens--. Column 6, line 35, after "movable" insert -- , --. Column 7, line 50, change "38 contain" to - -38 contain--. Column 7, line 65, change "circulating" to

Column 8 line 6l, after "fluids" insert -- --. Column 9, line 58, change "and or" to --and/or--. Column l0, line 7, change "form" to --from--. Column l0, line 62, change "shwon" to -- shown--. Column ll, line 6l, change "longitudianlly" to

Column l3 line 65, change "loses" to --losses--. Column 14, line 52, change "Fifgs" to --Figs--. - Column l5, line l2, after "channels" delete -- , --.

Column l7, lines 48-49, change "crosssection" t

Column 17, line 59, change "ciculated" to

Column 18 line 5, change "descibed" to --described--. Column 19, line 53, after "many" delete --are--. signed and sealed this

Thirteenth D 2 y of November 1979

SEAL

Attest:

Attesting Officer Acting Commissioner of Patents and Trademarks