Abstract:
A solar collector for focusing radiant energy having a longitudinal member having translucent refraction and a lens that is positioned to receive electromagnetic radiation from the sun having a variable cross sectional dimension along its length positioned in proximity to a vessel of liquid; where the solar energy is focused on the liquid at a plurality of focal points of different length. The solar collectors may be used in a system for power generation where the lens has a variable cross sectional profile along its length disposed in proximity to a liquid for converting an inlet stream of liquid to an outlet flow of steam and a heat engine responsive to the liquid flow of steam for generating mechanical energy. The system may be used to power electrical turbines to store energy or supply the grid. The lenses may of a variety of cross sectional dimensions to focus the solar energy on various focal points within the liquid path.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not Applicable  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable  
       DESCRIPTION OF ATTACHED APPENDIX  
       [0003]     Not Applicable  
       CROSS REFERENCE TO RELATED APPLICATIONS  
       [0004]     Not Applicable  
       FIELD OF INVENTION  
       [0005]     This invention relates generally to the field of solar energy and more specifically to a machine and system for solar power generation.  
       BACKGROUND OF THE INVENTION  
       [0006]     It has been known for some time how to employ the sun&#39;s radiation to heat water and to utilize the heated water in a variety of ways to generate power. Existing solar energy systems circulate water through a system exposed to solar radiation to generate mechanical power from steam which in turn is used to drive various power systems such as electrical turbines. A limitation of prior art systems has been the efficiency at which they convert solar energy to other energy forms. Even in those instances where adequate extraction of solar energy is achieved, a lack of efficient energy transfer apparatus has precluded achieving the degree of efficiency that is required for commercial success.  
         [0007]     U.S. Pat. No. 4,423,599 to Veale teaches a system in which solar energy is employed to boil a liquid to form a pressured gas the energy in which is converted to electrical energy in a special turbine and that uses a lens to focus the sun&#39;s energy onto a stream of water at a fixed focal point. This system fails to account for the reducing volume of the water as it is converted to steam and thereby focuses the energy of the sun at points where the maximum extraction of energy is not achievable. The present system overcomes these problems and others in a variety of new and useful ways.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     It is an advantage of this invention to provide efficient and practical system elements, and a system employing them for the generation of electricity, using solar heating as the energy source.  
         [0009]     Another advantage is to provide such a system in which solar energy is employed to convert water or other liquid to gas under pressure and then to expand that gas to operate a heat engine such as a gas or steam turbine.  
         [0010]     A further advantage is to provide a solar collector for focusing the sun&#39;s energy in the most efficient manner for use in solar energy conversion system.  
         [0011]     A further advantage is to provide an improved solar collector for use in converting a flow of water to a flow of steam by use of innovative lens configurations.  
         [0012]     Yet another advantage of the present invention is to disclose a variety of lens configurations for the maximum extraction of solar energy.  
         [0013]     Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, embodiments of the present invention are disclosed.  
         [0014]     In accordance with a preferred embodiment of the invention, there is disclosed a solar collector for focusing radiant energy having a longitudinal member having translucent refraction, a first top surface of the member that is positioned to receive electromagnetic radiation from the sun, a second bottom surface of the member formed by the member having a variable cross sectional dimension along its length positioned in proximity to a vessel of liquid, wherein the solar energy is focused on the liquid at a plurality of focal points of different length.  
         [0015]     In accordance with a preferred embodiment of the invention, there is disclosed a machine for power generation through solar energy having a solar collector panel having at least one lens, the lens having a variable cross sectional profile along its longitudinal dimension, a liquid path disposed in proximity to the lens for converting an inlet stream of liquid to an outlet flow of steam or vapor, and a heat engine responsive to the liquid flow of steam or vapor for generating a mechanical energy output.  
         [0016]     In accordance with a preferred embodiment of the invention, there is disclosed a system for power generation through solar energy having a longitudinal member having translucent refraction, a first top surface of the member that is positioned to receive electromagnetic radiation from the sun, a second bottom surface having a variable cross sectional dimension along the length of the member positioned above a body of contained liquid, wherein the solar energy is focused on a plurality of points on the opposite side of the second surface.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.  
         [0018]      FIG. 1  is schematic of electromagnetic radiation impacting on a solar concentrator tube.  
         [0019]      FIG. 2  is a is a perspective view of a solar collector/concentrator tube.  
         [0020]      FIG. 3A  is a cross sectional view of a solar collector/concentrator tube in accordance with a preferred embodiment of the invention.  
         [0021]      FIG. 3B  is a cross sectional view of lens in accordance with a preferred embodiment of the invention.  
         [0022]      FIG. 3C  is a cross sectional view of lens in accordance with a preferred embodiment of the invention.  
         [0023]      FIG. 3D  is a cross sectional view of lens in accordance with a preferred embodiment of the invention.  
         [0024]      FIG. 3E  is a schematic and cross sectional view of a solar collector/concentrator and lens with ambient electromagnetic radiation in accordance with a preferred embodiment of the invention.  
         [0025]      FIG. 3F  is a cross sectional view of a base plate for placement of a plurality of solar collector/concentrator tubes in accordance with a preferred embodiment of the invention.  
         [0026]      FIG. 4  is a schematic diagram of a power generation system in accordance with a preferred embodiment of the invention.  
         [0027]      FIG. 5  is a block diagram of a steam turbine power generation system in accordance with a preferred embodiment of the invention.  
         [0028]      FIG. 6A through 6H  are alternate cross sectional views of different solar lenses in accordance with a preferred embodiment of the invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0029]     Detailed descriptions of the preferred embodiment are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.  
         [0030]     Turning now to  FIG. 1 , there is shown schematic diagram of a solar collector tube  12  placed in such a position as to obtain maximum solar radiation  14  with reflector  16  in position to further enhance the collection of solar energy. Collector tube  12  can be of a variety of configurations as more fully described below with the goal of focusing maximum energy on a material from which energy is extracted such as water or other low boiling point liquid.  
         [0031]     A benefit of the inventive system disclosed herein is that a series of “solar concentrators”, or a solar collector in a single one pass or multiple pass tube or a bank of tubes in series or parallel enables maximum extraction of energy. The collector tube has a lens that focuses radiant energy to create heat in the liquid and/or vaporize a liquid in the tube that may or may not operate under a vacuum which in turn drives a turbine, drives a generator, etc. Prior art designs such as that shown in U.S. Pat. No. 4,423,599 are inefficient since the foci of the collection lens was at a constant height relative to the length of the tube.  
         [0032]     Turning now to  FIG. 2 , a tube  20  of length, l, 24 has an internal diameter, h, 25. At l=0, at one end of the tube  28 , liquid composition is 100% and the low boiling point liquid height is h=h, and the vapor composition is 0%. At l=l, or the at the opposite end of tube  28 , it is the opposite where all of the low boiling point liquid has been turned into vapor, the low boiling point liquid height is h=0, so liquid=0% and vapor=100%. As you move down the pipe from l=0 to l=l, the ratio of low boiling point liquid %/(liquid %+vapor %) decreases. As this ratio decreases, the height of the low boiling point liquid level decreases from h=h to h=0. In order for the solar collector to work optimally, which means the maximum vaporization of the low boiling point liquid and not instead, heating already formed vapor, its foci must be in the low boiling point liquid. Thus the present invention seeks to disclose a novel lens that changes shape (width and/or thickness) along the length of the tube so that the foci changes height from h=½ h (or some other point anywhere in the liquid volume at l=0) to the foci being at h=0 at l=l. Wall thickness W T    22  may be varied so that at the opposite end of tube  20 , wall thickness xW T    26  is a fraction of wall thickness  22 . As more fully described herein, the variation of the tube dimensions may be linear or non linear and alternatively may alter the inner dimension of the tube through which the water or low boiling point liquid flows. The inside of the tube  28  would preferably be coated with a commonly available material to insulate the system from both thermal and radiant energy loss.  
         [0033]      FIG. 3A  shows a cross sectional view of one of a plurality of collector tubes  30  that may be used in the inventive system disclosed herein. Tube  30  has flanged legs  34  for insertion into a rack (further shown in  FIG. 3F ) for stable placement of the tube into a system of solar collectors. Tube  30  has slots  32  for insertion of a lens (not shown) that may be of any of a variety of dimensions or configurations. The lens that is chosen may have any of a number of focal points  36  along the length of the collector tube  30  to maximize liquid vaporization. Reflector surface  38  may be placed on the inside diameter of the tube  30  to further enhance energy absorption by liquid and act as an insulator.  
         [0034]      FIG. 3B  shows a cross sectional view of lens  40  having a generally concave inner surface  41  for focusing the radiation of the ambient sunlight as desired. Lens  40  has two tabs  42  on opposite sides of lens  40  for insertion into slot  32 , for example, on a solar collector tube such as that shown in  FIG. 3A .  FIG. 3C  shows a cross sectional view of lens  44  having an alternative concave inner surface  45  for focusing the radiation of the ambient sunlight as desired and tabs  46  for insertion into a solar collector tube.  FIG. 3D  shows a cross sectional view of lens  40  having an alternative concave inner surface  49  for focusing the radiation of the ambient sunlight as desired and tabs  50  for insertion into a solar collector tube.  
         [0035]      FIG. 3E  shows a cross sectional view of solar collector tube  60  placed in position to receive solar radiation  64  for heating of liquid passing through tube  60  in inner cavity  65 . Tube  60  has a generally cylindrical body  70  with insertion slots  71  for reception of tabs  68  of a solar lens  62  in accordance with a preferred embodiment of the invention. Lens  62  has a multifaceted inner surface dimension  73  for focusing the solar radiation  64  in a plurality of foci points  66 ,  72 ,  74 ,  76 ,  78  and  80 . Depending on the desired extraction characteristics desired, lens  62  may have a cross sectional dimension that is linear across the length of the lens or may vary across its length down the tube according to any of a variety of functions. It may be smoothly linear, logarithmic, step or other function to achieve the desired results.  
         [0036]      FIG. 3F  shows a base  52  for placement in a solar concentrator system having a plurality of slots  54  for insertion of solar collector tubes such as that shown in  FIG. 3A  by inserting legs  34  into slots  54 . Base  52  may be employed on the roof of a building or other structure such as a free-standing stanchion to direct the sun&#39;s radiation to the solar collector tubes for maximum extraction of energy.  
         [0037]     The solar collector can also be use in existing systems to heat water for pools or for home use. Thus the solar collector would be designed to heat water and not vaporize it. Since 50% of electric home energy use is used in electric water heaters to heat water in the United States, this novelty will provide significant cost savings and energy usage reductions. In a house, the solar collector would be put in line to heat water to a specific temperature. This can happen two ways by design with a once through system or by installing a circulation loop with a delta-T differential temperature controller which would stop circulation when the desired temperature set point was reached. This same design will also work for heating pool water.  
         [0038]      FIG. 4  shows a schematic diagram of a basic system utilizing the inventive aspects of the present invention. Water is introduced to a tank  96  through an inlet line  92  or through a valve  94  from a separate source. Water is introduced through valve  100  through inlet  102  to a solar concentrator  114 . Solar concentrator  114  has a plurality of solar tubes aligned in such a way as to receive radiant energy and generate vapor. The collector/concentrator tubes can be under vacuum to lower the boiling point of the liquid and may contain any of a variety of liquids although water is preferably used. Temperature indicator gauge  104  and pressure indicator gauge  106  monitor system performance as desired. Pressurized vapor is delivered to a generator  142  which in turn generates electricity or stores power in a battery  128 . Power from the battery may be delivered to the load  132 , or excess may be transported to the grid  130 . Any unvaporized water is separated in vapor liquid separator  120  and reintroduced into the system. A heat exchanger  138  used to help condense vapor after expansion in the turbine into liquid and reintroduction into the vaporization system.  
         [0039]      FIG. 5  shows a block diagram of a basic turbine system according the present invention. Make up liquid  162  is introduced to a pre-heater  164  before introduction to the solar collector  166 . The make up liquid can be of any of a variety of liquids including low boiling point liquid, water or synthetic depending on the nature of the turbine, although conventionally it would be water. The liquid is vaporized in the collector  166  using solar collector tubes in accordance with the present invention. The solar collector tubes may be placed in certain embodiments on the roof of the structure housing the system in a series of holder trays for reception of maximum energy from the sun. In an alternative embodiment, the solar collector tubes may be mounted on a stanchion that moves with the sun to maintain the maximum exposure to the solar radiation.  
         [0040]     As the liquid-vapor mixture is obtained, it is introduced into the vapor-liquid separator  168  which in turn sends the vapor to the turbine  172  and the left over liquid to the condenser  170 . Spent vapor from the turbine  172  is also sent to the condenser for condensing and for reintroduction into the solar collector unit  166 . The turbine  172  powers a transmission generator  174  which in turn delivers electricity for storage into power storage unit  176 .  
         [0041]     Another benefit of the present invention is that, by design, the concentrating lens may be part of the solar collector tube in which the water (or low blow boiling point liquid) flows. This is significant in that this design allows for ultra low cost manufacturing, assembly, maintenance and replacement. The components would be manufactured from all plastics or a plastic tube with glass lens at costs far below that of existing technologies. These devices can be mounted on the ground, on a roof top or anywhere that would get optimal radiant energy from the sun. This configuration is easily determined using existing commercial radiant energy measurement devices.  
         [0042]      FIG. 6A through 6H  show a variety of lens collector configurations.  FIG. 6A  shows lens  200  having a multi-dimensioned bottom surface  202  to refract light to different focal points.  FIG. 6B  shows lens  204  having a smoothly varying convexity across the longitudinal dimension of the lens member from end  206  to end  208 . The cross section defining the lens at end  206  is composed of different arcs than the arcs defining the cross section at end  208 .  FIG. 6C  shows another lens  210  having a smoothly varying convexity where the end  212  has a smaller cross sectional dimension than opposite end  214 . This type of configuration focuses the radiant energy at a descending focal point length from the center of the lens to facilitate heating the maximum amount of liquid by having the energy in the liquid below and not focusing on the vapor portion of the liquid flow.  FIG. 6D  shows lens  216  having a concave bottom surface  217  and a cross dimensional variation of the thickness of the lens from end  218  to opposite end  220 .  FIG. 6E  shows lens  222  with a variation of a concave lens configuration on the bottom surface and a varying thickness of the lens across the length of the lens from end  224  to end  226 .  FIG. 6F  shows multifaceted lens  228  having a varying cross sectional surface area at end  230  from end  232 .  FIG. 6G  shows lens  234  with a step function style cross section that focuses light energy at several pre-determined focal points. The cross section of lens  234  may be of varying cross sectional surface area in a smooth function across its length or have some other varying function. It may also be non-varying across its length depending on the application.  FIG. 6H  shows lens  240  with saw tooth pattern  248  and a varying cross sectional surface area from end  242  to end  246 . All of the above lens configurations permit a fine tuning of the light refraction and focusing of energy in the stream of water or other liquid to best maximize the extraction of energy. Depending on the particular liquid, solar radiation and other factors, these configurations or a combination thereof might be employed on different lenses in the same system to achieve the maximum benefits. By having a lens configuration that changes across the length of the solar tube, as the water or other liquid is heated and converted to vapor or steam as the case may be, the focus of the sun&#39;s energy is more appropriately directed to the portion of the water or liquid that one would like to heat rather than the vapor.  
         [0043]     While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention.