Abstract:
This invention relates generally to a solar collector and photovoltaic converter with a concentrating reflective inner surface with a static fluid filter attached to the bottom half of a enclosure with a photovoltaic converter cell mounted to the under side of the hemi-spherical transparent top half of the enclosure.

Description:
BACKGROUND 
       [0001]    1. Field of Invention 
         [0002]    This invention relates generally a solar collector with a concentrating reflective surface with a static fluid IR filter attached to the bottom of a transparent enclosure with a photovoltaic converter device or cell mounted to the under side of the top of a transparent enclosure. 
         [0003]    2. Prior Art 
         [0004]    Photovoltaic device surfaces need to remain relatively cool to operate at maximum efficiency. There is a narrow spectrum of photon wavelengths that trigger a generation of electricity event when they impact the surface of photovoltaic device. All the photons in the tails of that spectrum outside the electricity generation segment only cause unwanted heating of the photovoltaic device, reducing its efficiency. Currently solar collectors use many different methods to avoid overheating of photovoltaic devices. Some use expensive Fresnel lenses to reflect the longer wavelengths that are not convertible by the cell away from the photovoltaic device and only serve to heat the photovoltaic device. Others pump a fluid such as water between the source and the reflector or between the cell and the reflector that will absorb the infrared spectrum, heating the fluid. They then reclaim the heat absorbed by the fluid by cycling this heated fluid through some type of heat exchanger using some of the electricity generated by the photovoltaic devices to pump the fluid. Water or a fluid with similar properties at a depth of ½ inch does an excellent job of filtering out the IR wavelength photons. Various dyes can be added to the fluid to also filter out the red, yellow and green wavelength photons which also are not convertible and only add heat. Depending on the concentration ratio which equals approximately the area of photovoltaic device face divided by the area of the inlet window, this may or may not be required. Secondary film filters can also be added to the underside of the inlet window to filter out the UV rays if required. Some do not utilize concentrators but rely on large surface area cells which must be kept clear of dust to be effective. 
       SUMMARY 
       [0005]    The general object of the present invention is to provide an economical solar collector and conversion apparatus. 
         [0006]    The specific objective of this invention is to provide a very low cost system for the generation of sufficient power to provide for the basic needs of a family in remote undeveloped regions of the world or for first responders in emergency relief of victims of hurricanes, tornadoes, earthquakes or tsunamis where there are sure to be significant power outages that:
       1. serves as a solar collector and power generating apparatus with little to no maintenance required and can generate potable water as a byproduct of its operation.   2. serves as a solar collector and power generating apparatus where the photovoltaic device is sheltered from dust and other contaminates.   3. serves as a solar collector and power generating apparatus where the portion of the incoming radiation that is of unconvertible wavelengths by a photovoltaic device is filtered prior to impact on the concentrating reflector.   4. serves as a solar collector and power generating apparatus where a significant portion of the effective wavelength photons of the impending radiation is reflected onto the face of a photovoltaic device.   5. serves as a solar collector and power generating apparatus that can function setting on ground or water.       
 
     
    
     
       DRAWINGS 
         [0012]    In order that the invention may be more fully understood it will now be described by way of example, with reference to the accompanying drawings in which: 
           [0013]      FIG. 1  is a front perspective view of a solar collector and photovoltaic converter showing an earth mounted embodiment. 
           [0014]      FIG. 2  is a section view of same. 
           [0015]      FIG. 3  is a front perspective view of a solar collector and photovoltaic converter showing a floating on water embodiment. 
           [0016]      FIG. 4  is a section view of same. 
           [0017]      FIG. 5  is an enlarged view of  FIG. 4  showing solar radiation entrance, reflection and escape patterns. 
       
    
    
     REFERENCE NUMERALS 
       [0018]    The same reference numbers are used to refer to the same or similar parts in the various views. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 10 
                 solar collector and photovoltaic 
               
               
                   
                   
                 converter 
               
               
                   
                 12 
                 bottom enclosure 
               
               
                   
                 14 
                 bottom reflective inner surface 
               
               
                   
                 16 
                 long wave length filter packet 
               
               
                   
                 18 
                 filter fluid 
               
               
                   
                 20 
                 photovoltaic device 
               
               
                   
                 22 
                 output cable 
               
               
                   
                 24 
                 top reflective inner surface 
               
               
                   
                 26 
                 inflation valve 
               
               
                   
                 28 
                 top enclosure 
               
               
                   
                 30 A 
                 solar ray directly reflected to 
               
               
                   
                   
                 photovoltaic device 
               
               
                   
                 30 B 
                 solar ray indirectly reflected 
               
               
                   
                   
                 to photovoltaic device 
               
               
                   
                 30 C 
                 solar ray escaping collector 
               
               
                   
                 32 
                 mounting skirt 
               
               
                   
                 34 
                 inlet window 
               
               
                   
                 36 
                 UV filter 
               
               
                   
                   
               
             
          
         
       
     
       DESCRIPTION 
       [0019]    In order that the invention may be more fully understood, solar collector and photovoltaic converter  10  will now be described by way of example with reference to the accompanying drawings. 
         [0020]      FIG. 1  illustrates an embodiment of solar collector and photovoltaic converter  10  for a land based fixed location mounting. It is comprised of bottom enclosure  12  that is open to the top with a bottom reflective inner surface  14 . This bottom reflective inner surface  14  takes on the shape of bottom enclosure  12 . Top Enclosure  28  is a transparent hemisphere with the same outside diameter as bottom enclosure  12 . Top reflective inner surface  24  covers the inside of top enclosure  28  with the exception of inlet window  34 . Photovoltaic device  20  is mounted toward the inside top of top enclosure  28 . 
         [0021]      FIG. 2  is a view of a section through solar collector and photovoltaic converter  10 . It shows long wavelength filter packet  16  that conforms to the inner surface of bottom enclosure  12 . Long wavelength filter packet  16  is a sealed packet of transparent flexible or rigid material filled with filter fluid  18 . If filter fluid  18  is water, a depth of approximately ½ inch is sufficient to filter out most of the radiation above 1.2 microns. Since solar rays  30  pass through filter fluid  18  the second time as they are reflected back through filter packet  16 , a ¼ inch deep filter packet  16  will suffice. Red, yellow, green and UV rays below 0.35 microns are also non-convertible by photovoltaic cells and can be filtered out by admixing appropriate dyes with filter fluid  18  if required for high concentration ratio solar collector and photovoltaic converters  10 . 
         [0022]    Another embodiment covers entrance window  34  with thin film UV filter  36  for even higher concentration ratio solar collector and photovoltaic converters  10  as shown in enlarged view in  FIG. 5 . 
         [0023]    The height of entrance window  34  ranges from approximately 30 degrees to 47 degrees. It is positioned on the face of solar collector and converter  10  at predetermined optimal positions based on where it will be utilized, to compensate for variations in the angles of incidence of solar rays  30  for various latitudes. The width of the entrance window  34  ranges from approximately 120 degrees to 200 degrees to allow for the daily variations of the angles of incidence in a land based system. 
         [0024]      FIG. 3  illustrates an embodiment of solar collector and photovoltaic converter  10  for a water based mounting. It is comprised of bottom enclosure  12  that is open to the top with a bottom reflective inner surface  14 . This reflective inner surface  14  takes on the shape of bottom enclosure  12 . Top enclosure  28  is a transparent hemisphere with the same outside diameter as bottom enclosure  12 . Top reflective inner surface  24  covers the inside of top enclosure  28  with the exception of inlet window  34  which runs completely around the circumference of top reflective inner surface  24 . It is positioned on the face of solar collector and converter  10  at predetermined optimal positions based on where it will be utilized, to compensate for variations in the angles of incidence of solar rays  30  for various latitudes. Photovoltaic device  20  is mounted toward the inside top of top enclosure  28 . 
         [0025]      FIG. 4  is a view of a section through solar collector and photovoltaic converter  10 .  FIG. 4  shows long wavelength filter packet  16  that conforms to the inner surface of bottom enclosure  12 . Long wave length filter packet  16  is a sealed packet of transparent flexible or rigid material filled with filter fluid  18 . If filter fluid  18  is water, a depth of approximately ½ inch is sufficient to filter out most of the radiation above 1.2 microns. Since solar rays  30  pass through filter fluid  18  the second time as they are reflected back through filter packet  16 , a ¼ inch deep filter packet  16  will suffice. Red, yellow, green and UV rays below 0.35 microns are also non-convertible by photovoltaic cells and can be filtered out by admixing appropriate dyes with filter fluid  18 . 
         [0026]    In one embodiment top enclosure  28  and bottom enclosure  12  are made from a rigid transparent material. In another they are made from a flexible material and the interior of the enclosure is inflated with a gas to give it shape. Inflation valve  26  is shown installed in top enclosure  28  for that purpose. In all embodiments output cable  22  is shown running from photovoltaic device  20  though top enclosure  28  and connecting to either an energy storage device or directly to a power consuming device such as a light, fan, cellular phone charger, etc, not shown in the drawings or part of this invention. 
       Operation: 
       [0027]    Standard photovoltaic devices  20  are able to convert photons of wave lengths between 0.35 and 1.2 microns to electricity. If the full spectrum of solar radiation were to impinge on the front surface of photovoltaic device  20 , the photons above and below this range would only serve to heat the photovoltaic device  20 , significantly reducing the efficiency with which it converts solar radiation  30  to electricity. 
         [0028]      FIG. 1  shows an embodiment of solar collector and photovoltaic converter  10  with mounting skirt  32  attached to the bottom of bottom enclosure  12 . This embodiment is designed for a ground installation. A clearing is constructed of sufficient diameter that solar radiation  30  is not blocked from inlet window  34  by surrounding buildings or vegetation. Solar collector and photovoltaic converter  10  is then placed on a bare patch of earth or sand with inlet window  34  facing in a southerly direction for a northern hemispheric location or a northern facing location for a southern hemispherical location. Rocks, dirt or other routine anchor mechanisms can be utilized to hold mounting skirt  32  in contact with the ground and keep solar collector and photovoltaic converter  10  in proper alignment. The earth, shaded by solar collector and photovoltaic converter  10 , makes a very good heat sink for the heat energy absorbed by fluid  18  in filter packet  16 . 
         [0029]      FIG. 3  shows solar collector and photovoltaic converter  10  floating on a body of water. In this embodiment, inlet window  34  runs completely around top enclosure  28  since it is very difficult to maintain a South or North facing attitude with a floating on water installation. Incoming solar rays  30  penetrate transparent top enclosure  28  through inlet window  34  and pass through long wave filter packet  16  which is approximately ¼ inch thick and made from a either rigid or flexible transparent material. A filter fluid  18  such as water will absorb most of the long wavelength radiation or infrared radiation above 1.2 microns that would heat the photovoltaic device  20 . Solar rays  30  pass through filter packet  16 , reflect off of bottom reflective inner surface  14 , and pass back through filter fluid  18 . They continue to be reflected from the interior reflective surfaces  14  and  24  until they either escape from solar collector and photovoltaic converter  10  through inlet window  34  or impinge on photovoltaic device  20 . If desired, red, yellow, green radiation and ultraviolet radiation below 0.35 microns can be filtered out by adding the appropriate dyes to filter fluid  18 . 
         [0030]      FIGS. 1 and 3  show section views of solar collector and photovoltaic converters  10  with inlet windows  34  that have been tailored to a latitude approximately midway in the US. One of the objectives of this invention is a completely static system with no moving parts in order to retain scalability of the system without having to consider large motors embodied in a solar tracking system and to maintain the possibility of low to no maintenance. A practical system depends on reflective surfaces  14  and  24 , covering the inside of bottom and top enclosures  12  and  28  respectively with the exception of inlet window  34  whose height is determined by the seasonal variation in the incidence angle of solar radiation at a given latitude. The width of window  34  ranges from approximately 120 degrees to 200 degrees for a fixed position land based solar collector and photovoltaic converter  10  as in  FIGS. 1 and 2  and is circumferential for water mounted installations as in  FIGS. 3-5 . 
         [0031]      FIG. 5  shows incident solar rays  30 A,  30 B and  30 C entering through entrance window  34  of cross sectional area X. Solar ray  30 A penetrates transparent top enclosure  28  and UV filter  36  if present and the transparent material of top side wall of filter packet  16 ; passes through filter fluid  18  which absorbs about 50% of its long wave length radiation; penetrates the transparent material of bottom side wall of filter packet  16 ; is reflected from bottom reflective inner surface  14 ; passes back through filter packet  26 , filter fluid  18  and filter packet  16  giving up almost the remainder of its long wave radiation and impinges on the active face of photovoltaic device  20 . 
         [0032]    Solar ray  30 B will continue bouncing about the inside bottom enclosure  12  and top enclosure  28  until it either hits the face of photovoltaic device  20  causing an electricity generating event or as solar ray  30 C illustrates, escapes back out inlet window  34 . The percentage of incoming light escaping randomly is roughly the ratio of cross sectional area X of inlet window  34  to the total surface area of the bottom and top reflective inner surfaces Y. The concentrating factor of the device is the cross sectional area X−X/Y divided by the cross sectional area of the photovoltaic device Z. The bandwidth of acceptable light incident on photovoltaic device  20  without causing overheating is determined by the concentration factor of solar collector and photovoltaic converter  10 . If the concentrating factor is 3/1, plain water will be quite acceptable as filter fluid  18 . If the concentrating factor is 10/1 or higher, filtration of the red, green, yellow and perhaps the UV are required to avoid dramatically reducing the efficiency of photovoltaic device by overheating.  FIG. 5  shows the installation of UV filter  36  attached to the underside of inlet window  34  for such a case. 
         [0033]    One of the other most vital human needs for individuals in remote areas or in emergency relief circumstances is often potable water. A serendipitous effect of solar collector and photovoltaic converter  10  is the sterilizing effect that it has on filter water when sunlight is allowed to pass though it for several hours. For this purpose long wavelength filter packet can be drained of potable water and refilled several times per day providing again a subsistence level of potable water. 
         [0034]    The preceding descriptions are for illustrative purposes and are not intended to limit the scope of this invention. The scope of the invention should be determined by the appended claims rather than by the specific examples given.