Abstract:
A device and system for generating electricity with a photovoltaic floatation device is provided. The device comprises one or more photovoltaic cells, which are attached to a panel that is removably attached to a floatation element. The device allows users to utilize the surface areas of water for placement of photovoltaic cells. Multiple devices can be mechanically connected to allow for the formation of one or more photovoltaic floatation device grids. The system comprises one or more photovoltaic floatation devices that are anchored to a particular area in a body of water and are electrically connected to one or more inverters.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]     This Application claims the benefit of U.S. Provisional Application Ser. No. 60/740,559 filed on Nov. 28, 2005, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a floatation device with a photovoltaic panel having photovoltaic modules. The device is able to float on water and generate electricity.  
       DESCRIPTION OF RELATED ART  
       [0003]     Solar energy has received increasing attention as an alternative renewable, non-polluting energy source to produce electricity as a substitute to other non-renewable energy resources, such as coal or oil that also generate pollution. Given the increase in the price of non-renewable resources such as oil, it has become even more advantageous for companies and individuals to look to solar energy as a cost saving alternative. However, one drawback of solar energy is that the photovoltaic cells used to generate the electricity require a large amount of space so that a large surface area of cells can be exposed to sunlight.  
         [0004]     This drawback is especially evident in areas where land is scarce and is needed for other applications. In these areas, land is far too valuable to commit to energy production. Thus, users in such areas are forced to purchase electricity from a power company or utilize expensive alternatives such as generators.  
         [0005]     However, in many areas bodies of water are plentiful. In much of these areas, individuals as well as companies own land containing bodies of water or bordering bodies of water. Much of the time, these bodies of water go untouched as the activities of the individual or company are confined to the land. Hence, it would be advantageous to utilize the vast amount of surface space of bodies of water for the placement of photovoltaic cells.  
         [0006]     One system disclosed in Japanese Patent Publication No. S57-17181 combines photovoltaic cells with a floating apparatus so that the cells can be floated on water. For example, the known system contains a floating body made up of a plurality of connected floating elements. The floating body has a plurality of solar cells attached thereon. The solar cells are electrically connected to an external current collector.  
         [0007]     However, the known art easily collects dirt and water on the top surface. Furthermore, the known art discloses a device where the user must dispose of the entire device if either the floatation element or the affixed solar cells become unusable. Moreover, in the known art, electrical wires that carry current between photovoltaic cells are completely exposed to the outside elements and can be easily damaged from strong winds and rocky tides.  
         [0008]     Therefore, a need exists for a photovoltaic floatation device that is designed to withstand the elements present in a body of water and allow for easy, cost effective maintenance.  
       SUMMARY  
       [0009]     In one embodiment, a photovoltaic floatation device comprises a photovoltaic laminate panel. The device further comprises a floatation element, wherein the photovoltaic laminate panel is removably attached to the floatation element.  
         [0010]     In another embodiment, a system for generating electricity comprises one or more photovoltaic floatation devices that are mechanically connected with one or more fasteners. The system further comprises one or more photovoltaic floatation devices electrically connected to one or more combiner boxes. The one or more combiner boxes are electrically connected to one or more combiner-combiner boxes. The system further comprises one or more inverters, wherein the one or more combiner-combiner boxes are electrically connected to the one or more inverters. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     Referring now to the drawings in which like reference numbers represent corresponding parts throughout:  
         [0012]      FIG. 1  is a perspective view of one embodiment of the photovoltaic floatation device.  
         [0013]      FIG. 2  is an end view of a cross section of the embodiment shown in  FIG. 1 .  
         [0014]      FIG. 3  is a top view of a cross section of the embodiment shown in  FIG. 1 .  
         [0015]      FIG. 4  is a cross section view of a PV laminate panel.  
         [0016]      FIG. 5  illustrates the interface of the PV laminate panel and the floatation element.  
         [0017]      FIG. 6  is a top view of two devices of the embodiment of  FIG. 1  connected.  
         [0018]      FIG. 7  illustrates a carabiner connector locking a pair of grommet tabs on adjacent floatation elements.  
         [0019]      FIG. 8  is a perspective view of an alternative of a photovoltaic floatation device with a foam insert inserted into the floatation element.  
         [0020]      FIG. 9  is a perspective view of another embodiment of a photovoltaic floatation device with individual tubular air bladders within the floatation element.  
         [0021]      FIG. 10  is a top view of a cross section of the embodiment of  FIG. 9 .  
         [0022]      FIG. 11  is a perspective view of another embodiment with two stabilizing pontoons attached to the side of a main body pontoon.  
         [0023]      FIG. 12  is a top view of two of the devices depicted in  FIG. 11  connected with a walkway placed over the connection area.  
         [0024]      FIG. 13  is a top view of another embodiment of two main body pontoons connected at each of their sides with one stabilizing pontoon, equal in length to the connected main body pontoons.  
         [0025]      FIG. 14  is a top view of one embodiment of a photovoltaic floatation device with a floating scaffold attached thereto.  
         [0026]      FIG. 15  is a schematic view of one embodiment of a photovoltaic floatation device system of the present invention fully installed and deployed in water.  
         [0027]      FIG. 16  illustrates a plan view of an array of connected photovoltaic floatation devices.  
         [0028]      FIG. 17  is a perspective view of one embodiment of a photovoltaic floatation device with a catamaran style floatation element. 
     
    
     DETAILED DESCRIPTION  
       [0029]     The present invention is directed to a photovoltaic floatation device, which comprises at least one floatation element, capable of floating on water, and at least one photovoltaic module attached thereto. Having generally described some of the features of the present invention, in the following description, reference is made to the accompanying drawings, which form a part hereof and that show by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized as structural changes may be made without departing from the scope of the present invention.  
         [0030]     Referring to  FIG. 1 , one embodiment of the present invention provides a photovoltaic floatation device  10 , which comprises a single floatation element  12  with a photovoltaic (PV) laminate panel  14  attached thereon. The floatation element  12  is inflatable and can be comprised for example of material such as PVC, TPO or Hypalon. However one skilled in the art would appreciate that the floatation element  12  can comprise any durable material that has a high impermeability to air and water.  
         [0031]     Referring to  FIGS. 1 and 2 , the floatation element  12  comprises a skin  16  forming a cavity  17  therein, which when inflated forms a generally rectangular shape with two ends  18   a  and  18   b,  two sides  20   a  and  20   b,  a top  22  and a bottom  24 . Attached, to the skin  16  of the floatation element  12 , for example with a heat weld, is an inflation device  26 , which allows for the inflation and deflation of the floatation element  12 . Attached along the outer perimeter of the floatation element  12 , for example with a heat weld, are grommet tabs  28 , which will be described in more detail later in the application.  
         [0032]     Furthermore, an overpressure valve  30  is attached to the skin  16  of the floatation element  12  at a height that is above the waterline of the device  10 , and promotes the pressure equalization in the floatation element  12 . The proper air pressure is maintained within the floatation element  12  by an auxiliary pressurizing pump (not shown).  
         [0033]     The top  22  of the floatation element  12  is sloped, and can have any slope that promotes the shedding of water and dirt from the PV laminate panel  14 . In one embodiment the slope is about  5  degrees or less so that the loss of solar radiation exposure is minimized. Thus, when the PV laminate panel  14  is attached to the top  22  of the floatation element  12 , the flexible nature of the panel  14  adopts the sloped shape of the top  22  of floatation element  12 . This prevents water and dirt from collecting on the top of the PV laminate panel  14 .  
         [0034]     Referring to  FIGS. 2 and 3 , the floatation element  12  comprises a plurality of internal support walls  40  attached to the top  22  and bottom  24  of the floatation element  12 , for example by heat welding. The internal support walls  40 , which act as a support structure for the floatation element  12 , form the top  22  of the floatation element  12  into a plurality of arc shaped sections  42  of skin  16 . The internal support walls  40  extend longitudinally along, and parallel to, sides  20   a  and  20   b  of the floatation element  12 .  
         [0035]     However, the internal support walls  40  do not extend entirely to ends  18   a  and  18   b.  Therefore, the air space  41  between the internal support walls  40  remains in fluid communication at all times. The height of the internal support walls  40  determines the slope of the top  22  of the floatation device  10  when the device is fully inflated.  
         [0036]     Removably attached to the floatation element  12  is the PV laminate panel  14  that has one or more photovoltaic modules affixed thereon. Examples of a flexible panel with one or more photovoltaic modules affixed thereon are described in U.S. Pub. Nos. 2004/0144043 and 2005/0072456, incorporated by reference herein. The flexible panel can be made of polymers such as PVC or any other suitable flexible materials, such as fabric, nylon, canvass, etc.  
         [0037]     Referring to  FIG. 4 , the incorporated publications disclose a combination roofing panel and solar module that includes a flexible membrane  70  and a plurality of elongated solar or photovoltaic modules  60  arranged side-by-side, end-to-end, and/or otherwise adjacent to each other. The photovoltaic modules  60  are attached with an adhesive  72  to a flexible membrane  70 . The photovoltaic modules  60  are adhered to top surface  74  of the flexible membrane  70 . An exemplary photovoltaic module  60  that can be used is a UNI-SOLAR® PVL module, available from United Solar Ovonic, 3800 Lapeer Road, Auburn Hills, Mich. An exemplary flexible membrane  70  that can be used is a single-ply membrane, e.g., an EnergySmart® S327 Roof Membrane, available from Sarnafil, Inc. Roofing and Waterproofing Systems, 100 Dan Road, Canton Mass. However, one skilled in the art would appreciate that other types of photovoltaic modules  60  could be used such as crystalline modules  60 .  
         [0038]     The photovoltaic modules  60  include negative and positive internal soldering pads  76   a (−) and  76   b (+), respectively. Apertures  78   a  and  78   b  are formed through the flexible membrane  70 , adhesive  72  and a lower portion of the photovoltaic module  60 , to access the internal soldering pads  76   a  and  76   b.  Electrical connections  80   a  and  80   b  are formed within the apertures  78   a  and  78   b,  between the internal module soldering pads  76   a  and  76   b  and the intermodule soldering connection leads  82   a  and  82   b.    
         [0039]     As a result, the internal module negative electrode soldering pads  76   a,  electrical connection  80   a,  and wire connection lead  82   a  provide an electrical circuit. The internal positive electrode soldering pads  76   b,  electrical connection  80   b,  and wire connection lead  82   b  provide an electrical circuit connected in series to the adjacent negative electrode soldering pads  76   a.  If necessary, one or more insulative layers  84  can be adhered to the bottom surface of the flexible membrane  70  and over the wire connection leads  82   a  and  82   b.  The negative and positive wire connection leads  82   a  and  82   b  are then ran out of the flexible membrane and a waterproof connecter (not shown) is attached at their ends.  
         [0040]     The PV laminate panel  14  is removably attached to the floatation element  12  with fasteners such as zippers, buttons, snaps, kedering, hook and loop fasteners, laces, twist-locks, magnets or any other fasteners capable of securely and removably attaching the PV laminate panel  14  to the floatation element  12 . For example, referring to  FIG. 5 , heat welded onto the top  22  of the floatation element  12  are a group of teeth  90 , with a slider  92  attached therein, which are part of a zipper mechanism. Attached with a heat weld to the outer edge of the PV laminate panel  14  are a second group of teeth  94 . In order to attach the panel  14  to the floatation element the slider  92  is used to engage, and connect, both groups of teeth  90  and  94 . Furthermore, the wire connection leads  82   a  and  82   b  can extend out from the bottom of the PV laminate panel  14  at the interface of a corner of the floatation element  12  and PV laminate panel  14 .  
         [0041]     Referring to  FIG. 6 , in another embodiment, grommet tabs  28  are attached along sides  20   a  and  20   b  of the floatation element  12 , for example by a heat weld. Referring also to  FIG. 7 , carabiner connectors  29  are used to lock together grommet tabs  28  attached along the edge of the floatation elements  12  of the two devices  10 . Alternatively, one or more hook-and-loop fasteners, attached along the edge of the two devices with a heat weld, may be used to connect multiple devices.  
         [0042]     Referring to  FIG. 8 , in another embodiment a top portion  57  of the floatation element  12  comprises a foam insert  102  that is capable of floating on water. The foam insert  102  is comprised of Styrofoam, polyisocyanurate, or alternatively, a 2-part catalytic foam. The top portion  57  is attached to a bottom portion  106 , for example with a heat weld, at an intermediate layer  61  of skin  16 . The top portion  57  of the floatation element  12  is defined by a top layer  59  of skin  16  and the intermediate layer  61  of skin  16 . In one embodiment, a top portion  104  of the foam insert  102  has a sloped pitch of 5 degrees or less. The bottom portion  106  of the floatation element  12  is inflatable.  
         [0043]     The insert  102  can be inserted into, and removed from, the top portion  57  of the floatation element  12  through an opening  108  in the skin  16  of the floatation element  12 . The opening  108  is created by a flap  110  of fabric, which for example is sealed and unsealed with a zipper mechanism. Alternatively, the foam insert  102  may be inserted into the top portion  57  during manufacturing and permanently sealed into the skin  16  of the floatation element  12 .  
         [0044]     In another embodiment, one large floatable foam insert  102  may be placed into the entire floatation element  12 . In this embodiment, there are no inflatable air bladders. The foam insert  102  is rigid, and thus maintains its intended shape. Alternatively, a two part polyurethane mixture of float gel, or other floatable material, can be used in place of the foam insert  102 .  
         [0045]     Referring to  FIGS. 9 and 10 , in another embodiment, the floatation element  12  comprises one or more air bladders  50 . The air bladders  50  are generally tubular in shape and can be attached with a heat weld to the inner side of the skin  16  of the floatation element  12 .  
         [0046]     The one or more air bladders  50  are arranged longitudinally from one end  18   a  of the floatation element  12  to the opposite end  18   b.  However, one skilled in the art would appreciate that the air bladders  50  could be arranged in various configurations within the floatation element  12 . Furthermore, in one embodiment, the air bladders  50  and skin  16  of the floatation element  12  are made of bullet proof material to prevent vandals from easily deflating the devices  10 .  
         [0047]     The one or more air bladders  50  are linked to, and in fluid communication with one another so that when one air bladder  50  is inflated, air is dispersed to all the linked air bladders  50 . Alternatively, the air bladders  50  may be isolated, and not in fluid communication with one another. In this alternative, each air bladder  50  is inflated independently of the other air bladders  50  so that in the event one air bladder  50  is damaged, the damaged air bladder  50  does not affect the air pressure in the remaining air bladders.  
         [0048]     When the air bladders  50  are linked, the floatation element  12  includes one inflation device  26 , which extends out from, and can be heat welded to, the skin  16  of the floatation element  12 . This allows for simultaneous inflation of all of the linked air bladders. Alternatively, if the air bladders  50  are isolated, each air bladder  50  may have a separate inflation device  26  extending out from the skin  16  of the floatation element  12 , allowing the user to supply air to each air bladder  50  individually.  
         [0049]     One method of inflating the skin  16  involves connecting an air source to an inflation device  26 . The inflation device  26  may comprise a valve, which allows for the free flow of air when engaged by an air compressor. However, one skilled in the art would appreciate that the inflation device  26  can be any passage capable of exposing the inside of the floatation element  12  to an air source and preventing the air from escaping during use of the device  10 .  
         [0050]     Referring to  FIGS. 11 and 12 , in another embodiment of the present invention, the floatation element  12  of the photovoltaic floatation device  10  comprises three separate floatation objects  120 ,  122   a  and  122   b.  These floatation objects  120 ,  122   a  and  122   b  comprise a main body pontoon  120  and one or more stabilizing pontoons  122 , which are attached to the main body pontoon  120 .  
         [0051]     Referring to  FIG. 12 , the one or more stabilizing pontoons  122  are removably attached to the main body pontoon  120 . The stabilizing pontoons  122   a  and  122   b  can be removably attached to the main body pontoon  120  with carabiner connectors  29  that interlock with grommet tabs  28 , which are attached along the sides  124   a  and  124   b  of the main body pontoon  120  and the side of the stabilizing pontoon  122 . Alternatively, the stabilizing pontoons  122  can be removably attached to the main body pontoon  120  with zippers, kedering, snaps, laces, hook and loop fasteners, magnets or any other type of re-useable fastener that is capable of withstanding the pulling force on the pontoon elements  122  from the current in the body of water. Alternatively, the stabilizing pontoons  122  are permanently connected to the main body pontoon  120  with for example glue or a heat weld.  
         [0052]     Both the main body pontoon  120  and the stabilizing pontoons  122  are inflatable. Alternatively, a foam insert  102 , or other suitable floatable material, is placed into the main body pontoon  120  and/or the stabilizing pontoons  122 .  
         [0053]     Furthermore, a walkway  130  can be laid along the area where multiple devices are connected. The walkway  130  can be attached with straps or alternatively may just be laid on top of the devices without any attachment mechanism. The walkway  130  comprises a plastic material, for example PVC. The walkway  130  allows a user to walk along the sides of the connected photovoltaic floatation devices  10 . This allows for easy access to the devices  10  when adjustments need to be made or the floatation element  12  needs to be re-inflated or inserted with a new foam insert. For example, a user can use the walkway  130  to access the tops of the photovoltaic floatation devices  10  in order to remove a defective PV laminate panel  14  and replace said panel  14  with a new working panel  14 .  
         [0054]     Referring to  FIG. 13 , in another embodiment, two main body pontoons  120  are attached at their ends. The two main body pontoons  120  are permanently heat welded together. Alternatively, the two main body pontoons  120  may be attached with grommet tabs  28  and carabiner connectors  29 .  
         [0055]     Two stabilizing pontoons  140   a  and  140   b,  each of which are as long as the combined length of the connected main body pontoons  142 , are then attached along the sides of the connected main body pontoons  142 . The stabilizing pontoons  140   a  and  140   b  are permanently affixed with a heat weld to the connected main body pontoons  142 . Alternatively, The stabilizing pontoons  140   a  and  140   b  are attached to the sides of the connected main body pontoons  142  with grommet tabs and carabiner connectors.  
         [0056]     In this configuration, the connected main body pontoons  142  are kept rigid and straight with tension caused by the stabilzing pontoon elements  140 . This configuration may be particularly useful in rough waters where reinforcement of the connection between the connected main body pontoons  142  is advantageous.  
         [0057]     Referring to  FIG. 14 , in another embodiment, the photovoltaic floatation device  10  can be attached to one or more floating scaffolds  146 . The floating scaffolds  146  are attached along the perimeter of the device with fasteners such as grommet  28  tabs in combination with carabiner connectors  29 . The one or more floating scaffolds  146  give shape and rigidity to the device  10 .  
         [0058]     The PV laminate panel  14  can be attached to the floatation element  12  before or after the floatation element  12  is inflated. When assembling the photovoltaic floatation device  10 , the floatation element  12  may be rolled up into a cylinder shape, with the PV laminate panel  14  already attached, with an air passage  26  exposed.  
         [0059]     The device may be both inflated and deployed simultaneously. While in its rolled state, the device  10  may be placed in the water, an air supply may be connected to the exposed inflation device  26  and the cavity formed by the skin  16  inflated with air. As the cavity formed by the skin  16  is inflated, the floatation element  12  will begin to unroll as it expands with air. Thus, the floatation element  12  can be unrolled and prepared for use simply by inflating it. Alternatively, the user can manually unroll the floatation element  12  on the shore, inflate it and then deploy the device into the water from the shore.  
         [0060]     To deploy one or more photovoltaic floatation devices  10 , a user can inflate the cavity formed by the skin  16  of the floatation element  12  after the device  10  is placed into the water. A single device  10  is placed into the water, inflated, and then connected mechanically to a second device  10  with grommet tabs  28  and carabiner connectors  29 . This process is repeated where a second device  10  is then mechanically connected to the already deployed device  10 , the second device  10  is then inflated and finally deployed. The user can repeat these steps until the desired number of devices  10  have been deployed. The user may deploy the devices from the shore or from a floating body in the water. Electrical cables are then ran from the devices  10  to one or more combiner boxes, which combine the current produced by two or more devices  10 .  
         [0061]     In another embodiment, the user inflates the number of devices  10  the user desires to deploy. The user then mechanically, or magnetically, connects the assembled devices  10  together. Finally, the user deploys the assembled and connected devices  10  into the water as a batch. This method may be more feasible in instances where the user has a lot of space to spread out the fully assembled devices  10  on the shore before deployment.  
         [0062]     In the embodiment of the device with a foam insert, the bottom portion of the floatation element is inflated and then the foam insert is inserted into the top of the floatation element. Once the floatation element is fully assembled, the device is deployed into the water. In the case of multiple devices, one device is placed into the water and then mechanically, or magnetically, connected to a second device, which is then placed into the water. This step is repeated until the specified number of devices have been placed into the water.  
         [0063]     Referring to  FIG. 15 , while in use the photovoltaic floatation device  10  is located on a body of water. One or more electrical cables  150  are used to electrically connect the photovoltaic modules of the multiple devices  10  to one or more combiner boxes  152 . The combiner boxes  152  are then connected with electrical cables  154  to combiner-combiner boxes  153 , which combine the current from the multiple combiner boxes  152 . The current from the combiner-combiner boxes  153  is then transferred through an electrical cable  156  to an inverter  158  that is located in an area accessible to the photovoltaic devices  10 .  
         [0064]     The combiner boxes  152  and the combiner-combiner boxes  153  rest on floats  160  in the body of water. The floats  160  are also connected to counterbalance weights  161  to prevent the floats  160  from flipping over in rough water. Furthermore, the floats are connected to the one or more photovoltaic floatation devices with a rope  163  to prevent the floats  160  from being carried away from the currents. Alternatively, the combiner boxes  152  and the combiner-combiner boxes  153  rest along the interface, for example on a walkway, where two or more devices  10  are attached.  
         [0065]     The photovoltaic floatation device  10  is placed in a body of water, where it floats on the surface while exposing the photovoltaic modules  60  to sunlight. The photovoltaic floatation device  10  is secured to a desired location within the body of water with anchor cables  162 , which are attached to an end  164  of the photovoltaic floatation device  10 , with for example a carabiner connector and grommet tabs. The anchor cables  162  are then secured to an anchor  166 , which has been sunk to the bottom of the body of water.  
         [0066]     The length of the anchor cables  162  is varied depending on the freedom of movement the user desires of the photovoltaic floatation devices  10  as well as the depth of the body of water. Furthermore, the strength of the anchor cables  162  can be varied depending on the severity of the potential surge forces present at the surface of the body of water.  
         [0067]     Referring to  FIG. 16 , multiple photovoltaic floatation devices  10  are mechanically, or magnetically, connected to form a photovoltaic floatation device grid  170 . In this configuration, a plurality of photovoltaic floatation devices  10  are arranged both side-by-side and end-to-end so that a grid-like organization results. Multiple devices  10  are electrically connected to combiner boxes  152 , which receive current from the devices  10  and transfer the current to either a combiner-combiner box  153  or an inverter  158 . Furthermore, the plurality of photovoltaic flotation devices  10  are mechanically connected with grommet tabs  28  and carabiner connectors  29 . Photovoltaic modules can also be electrically connected as described in U.S. Publication Nos. 2004/01440434 and 2005/0072456.  
         [0068]     Referring to  FIG. 17 , in another embodiment the PV laminate panel  14  is removably attached to a catamaran style floatation element  12 . The floatation element  12  includes two fiberglass floats  300 , which are shaped like long, skinny ovals, similar to the shape of a canoe. Attached at each end of the floats  300  are sloping bars  302 , which attach two parallel floats  300  at both ends of the floats  300 . The sloping bars  302  are attached to the floats with bolts. However, one skilled in the art would appreciate that the sloping bars  302 , or other suitable support elements, can be attached to the floats  300  in any way that would adequately secure the bars  302  to floats  300  and withstand the current forces in the body of water.  
         [0069]     Heat welded to the sloping bars  302  are a set of teeth, which along with teeth that are attached at the ends of the PV laminate panel  14  form a zipper mechanism  304 . The PV laminate panel  14  is stretched between the two parallel sloping bars  302  and attached with the zipper mechanism  304  to both bars  302 . Once fully attached the PV laminate panel assumes the sloped shape of the sloping bars  302 .  
         [0070]     The foregoing description of embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.