Abstract:
A system for the generation of electric power for use in connection with a water feature, such as a swimming pool, lake, pond and the like. The system includes an array of photovoltaic cells within a continuous membrane or joined to a separate membrane, the membrane being sized to fit atop or within the water feature when exposing the photovoltaic cells to ambient light.

Description:
TECHNICAL FIELD 
       [0001]    The present invention involves a novel system for the generation of electric power. Water features, such as swimming pools, lakes and ponds, by their very nature, have significant surface areas which, for the most part, remain unused. The present invention suggests that electric power can be generated by taking advantage of such water features by positioning an array of photovoltaic cells on or within such areas for exposure to ambient light. 
       BACKGROUND OF THE INVENTION 
       [0002]    Photovoltaics involve the application of solar cells for energy by converting sunlight including sun ultraviolet radiation directly into electricity. Photovoltaic production is perhaps the fastest growing form of energy technology whose use is doubling each year. 
         [0003]    Solar cells are commonly employed on the roof tops of buildings. Oftentimes, however, a building owner might resist the use of photovoltaics to generate energy for aesthetic reasons and because of the significant cost associated with installing devices which use this technology. Such devices include the packaging of multiple photovoltaic modules creating photovoltaic arrays. These arrays receive photons from sunlight increasing electrons to higher energy states thereby creating electricity. These photodiodes create current entirely due to transduced light energy. 
         [0004]    The first practical application of photovoltaics was to power orbiting satellites and other spacecraft while today these devices are used for grid connected power generation. When this is done, an inverter is used to convert the DC to AC for residential, commercial and industrial use. There is also a smaller market for off grid power for remote dwellings, roadside emergency telephones, remote sensing and cathodic protection of pipelines. 
         [0005]    When photovoltaic cells require protection from the environment, they are usually packaged tightly behind a glass sheet. To increase power, cells are electrically connected together to form photovoltaic modules or solar panels. Newer alternatives to standard crystal and silicone module manufacturing techniques include casting wafers, thin film fabrication (CdIe, CIGS, amorphous Si, microcrystalline Si), concentrator modules, “silver” cells, and continuous printing processes. Photovoltaics are available as thin plastic sheathing from companies such as Innovative Solar Technologies. As such, they can be made as continuous membranes having individual photovoltaic cells contained therein, or as separate cells connected to one another electrically thus creating either a stand alone membrane or a series of slats or “shingles” which can be used in conjunction with one another for suitable energy production. 
         [0006]    As noted previously, it is common, in either residential or commercial facilities, to place solar panels containing photovoltaic cells on the rooftop of a structure as this is bound to capture more ambient light energy than in comparable locations. Clearly, positioning is dictated by the need to expose the photovoltaic panel skyward to receive the most unobstructed sunlight for the majority of the day. Further, although surface area is a primary consideration and rooftops may be restricted in this regard, at least solar panels placed on roofs are less likely to be obstructed by ground surface features. 
         [0007]    Despite the obvious benefits of placing photovoltaic arrays on rooftops, such placement is not within its drawbacks. Among them is the recognition that preexisting buildings are not always situated such that their roofs capture the most amount of ambient light that might otherwise be available. Further, roofs have limited surface areas as they were built not necessarily to capture maximum ambient light energy but to simply act as a secure covering for a structure or dwelling In addition, solar panels incorporating photovoltaic arrays can be expensive to install requiring a skilled applicator and significant dedicated hardware to accomplish the task. Even when done professionally, such installations can result in roof leakage and structural compromise beyond the fact that, as noted, in residential settings, solar panels are oftentimes considered too “industrial” a look to justify the implementation. 
         [0008]    It has now been recognized through the present invention that there remains an untapped area for the application of photovoltaics which may be far superior to current installations. For example, in residential settings, many homeowners own swimming pools which are not only placed in sunny portions of one&#39;s property but exhibit large surface areas which for most of the time remain coveted with one&#39;s standard pool cover. These pool covers are used as a security feature preventing unwanted access by infants, larger persons, pets and debris. Additional benefits include absorbing sunlight to heat the pools as well as to prevent debris, such as leaves, from intruding within them. It is has now been determined that with the advent of thin film photovoltaic cells and other electricity generating processes the surface of a water feature, such as a swimming pool, pond or lake including a waste water pond would be an ideal environment in which to place one or more photovoltaic elements for the generation of electrical energy heretofore untapped. 
       SUMMARY OF THE INVENTION 
       [0009]    A system for the generation of electric power for use in connection with a water feature, such as a swimming pool, lake, pond and the like. The system includes an array of photovoltaic cells within a continuous membrane or joined to a separate membrane, the membrane being sized to fit atop or within the water feature when exposing the photovoltaic cells to ambient light. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0010]      FIG. 1  is a perspective view of a typical in ground swimming pool having the present invention installed therein. 
           [0011]      FIGS. 2   a ,  2   b ,  2   c  and  2   d  are examples of typical photovoltaic cell arrays taken along line  2 - 2  of  FIG. 1 . 
           [0012]      FIG. 3  is a top plan view of a typical water feature, such as a lake or pond having the present system installed therein. 
           [0013]      FIGS. 4   a ,  4   b ,  4   c  and  4   d  are cross sectional views of various vault installations showing how swimming pool covers are typically stored, all of which can be used in implementing the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    The present invention involves a system for the generation of electric power for use in connection with a water feature. In turning to  FIG. 1 , one such water feature is shown in the form of an in ground swimming pool  10  commonly in use both domestically and commercially. Swimming pool  10  is surrounded by walkway  11 , generally of concrete or composite material containing water body  12 . 
         [0015]    As stated previously, in order to maintain security and safety, increase pool temperature as well as to reduce debris accumulation within water body  12 , pool cover  13  is drawn over virtually the entire surface area of pool  10  when the pool is not in use. Under ordinary circumstances, cover  13  is of a plastic composition and ideally floats atop water body  12  for its stated purposes. To assist in payout and removal of pool cover  13 , roller  14  is provided which can either be turned mechanically or through motor actuation providing a neat roll when water body  12  is exposed for use. 
         [0016]    However, unlike prior art pool covers, the present system is capable of not only protecting water body  12  from the intrusion of debris, unwanted swimmers and water temperature elevation and conservation but also of generating electrical DC power. This is done by using as either a stand alone membrane of photovoltaic cells or as individual cells joined to a supporting membrane to constitute the cover. Again, the photovoltaic cells can be continuous sheet material or individualized elements which are electrically joined. In this regard, reference is made to  FIG. 2 . 
         [0017]      FIGS. 2   a - 2   d  show, in cross section, various alternative embodiments constituting the appropriate cover useful in practicing the present invention. For example, in turning to  FIG. 2   a , a single sheet of flexible photovoltaic material made up of individual cells continuously arranged thereon is shown as membrane  20  having cells  21 ,  22 ,  23 , etc., situated therein. As noted previously, membranes of this type are available commercially. One such manufacturer is Innovative Solar Technologies. Membrane  20  can be used alone as pool cover  13  installed as shown in  FIG. 1 . Alternatively, as noted in reference to  FIG. 2   b , membrane  13  can comprise composite  24  whereby membrane  20  as described with reference to  FIG. 2   a  having continuous photovoltaic cells  21 ,  22 ,  23 , etc., is bonded to membrane  25  which can be something as common as a preexisting pool cover enabling composite  24  to reside on top of or submerged within water body  12 . 
         [0018]    As yet a third embodiment, pool cover  13  can be composed of membrane  26  as shown in  FIG. 2   c.  In this embodiment, support membrane  25  can act as a cover for pool  10  and include individualized slats or shingles of photovoltaic cells  27 ,  28 ,  29  and  30  electrically connected to one another or to a common interface for the collection of DC power located proximate to the water feature. 
         [0019]    Finally, pool cover  13  can be composed of membrane  31  including protective sheathing  32  surrounding photovoltaic cells  33 ,  34 ,  35 , etc which can either be individual cells ( FIG. 2   c ) or a continuous film of cells ( FIGS. 2   a  and  2   b ). The configuration of  FIG. 2   d  offers the advantage of protecting the photovoltaic material in environments where the water feature may cause degradation of the photovoltaic cells prematurely were such protection was not provided. 
         [0020]    Up to this point, the invention has been described in terms of a swimming pool cover such as cover  13  of  FIG. 1 . However, recognizing that other water features can be equally suitable for the implementation of the present invention, reference is made to  FIG. 3 . 
         [0021]    In turning to  FIG. 3 , water feature  40  is shown in the form of a lake, waste water or fresh pond or the like. Membrane  42  can be cast or otherwise drawn over all or a portion of water mass  41  presenting a substantial area from which photovoltaic energy can be gathered. Energy so gathered within membrane  42  can be communicated via lines  43  to transfer box  44  in which the energy can either be transferred as DC or converted to AC as needed. 
         [0022]    Turning back to the swimming pool environment, reference is made to  FIG. 4  showing alternative embodiments typical of how pool covers are stored and deployed. 
         [0023]    In turning to  FIG. 4   a , pool  50  is shown in partial cross section having water body  51  and appended vault  55  housing toll  53  of pool cover membrane material. Membrane  52  is paid out from roll  53  through opening  54  in vault  55 . All photovoltaic membrane embodiments of the present invention can constitute membrane  52 . A similar configuration is shown in  FIG. 4   d  where vault  83  is situated within pool  80  adjacent water body  81  housing roll  85  with membrane material  82  paid out or drawn within vault  85  through opening  84 . 
         [0024]      FIGS. 4   b  and  4   c  show arrangements in which membrane  61 - 63  ( FIG. 4   b ) or membrane  72  ( FIG. 4   c ) is paid out from roll  65  and  70 , respectively for a position at the bottom of water bodies  61 - 71 . These embodiments used within pools  60  and  70  show the use of the pay out of singular membrane  72  floating atop water body  71  in the case of the embodiment of  FIG. 4   c  or the pay out of dual membranes  62 - 63  in the case of the embodiment of  FIG. 4   b . All of the embodiments of  FIG. 4  are suitable for the containment of the photovoltaic membranes of the present invention such that the basic figuration of standard pools need not be modified to embody this invention on a broad scale.