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[0001]     This application claims the benefit of U.S. Provisional Application No. 60/512,427 filed Oct. 20, 2003 and titled Swimming Pool Solar Heating Bag. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates to heating of water by solar radiation.  
         [0003]     Heating of water by means of electricity or gas is well known and effective. But, it is costly. Passive solar heating of water has been disclosed as an alternative. However, known apparatus and systems suffer from one or more of the following disadvantages. They are difficult to manufacture, are expensive, and are not easily portable or foldable.  
       SUMMARY OF THE INVENTION  
       [0004]     The disadvantages discussed above are overcome in systems embodying the invention.  
         [0005]     A solar heating system for heating a pool of water includes a water bag formed of materials which enable the water bag to be deflated and compressed so as to occupy little space, when not in use. When the water bag is in use it is inflatable and expandable so as to contain a substantial amount of water which can be heated by the rays of the sun absorbed by the water bag. A water bag embodying the invention can be formed of inexpensive non-porous materials (e.g., plastic, rubber or canvas) of a texture and color which can absorb the rays of the sun and heat the contents of the water bag. The water bag is very portable and can be set up so as to be filled with water which can be heated quickly and easily. When not in use the water bag can be folded or rolled up taking up very little storage space. It does not interfere with the use of the pool of water it is intended to warm. It can be set up any place, close to the pool of water or by using longer hoses it can be located away from the pool, where the best sunlight and solar heat is available. The water bag can be coupled via hoses and valves to a pool of water to permit water to flow through the bag continuously. Alternatively, the valves may be used to allow the bag to be filled with water from a pool of water and for the water to be held in the bag until it is heated for a predetermined period or time or until it reaches a predetermined temperature, before the heated water is discharged into the pool of water. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     In the accompanying drawings like reference characters denote like components; and  
         [0007]      FIG. 1  is an isometric view (not to scale) showing two sheets for forming a solar heating water bag embodying the invention;  
         [0008]      FIG. 1A  is a simplified top view (not to scale) of two sheets bonded together to form a solar heating water bag embodying the invention;  
         [0009]      FIG. 2  is a top view (not to scale) of the water bag of  FIGS. 1 and 1 A with the addition of: a) orifices for letting water into and out of the water bag; and b) ribs;  
         [0010]      FIG. 2A  is a cross-sectional view of the water bag of  FIG. 2  showing the ribs and the sheets expanded relative to each other;  
         [0011]      FIG. 3  is a top view (not to scale) showing a water bag embodying the invention located adjacent to a swimming pool;  
         [0012]      FIG. 4  is a side view (not to scale) of the water bag in a deflated (not used) condition;  
         [0013]      FIG. 4A  is an expanded view (not to scale) of one end of the water bag;  
         [0014]      FIG. 4B  is a side view (not to scale) of the water bag of the invention in a rolled up condition;  
         [0015]      FIG. 5  is a view (not to scale) of a water bag, embodying the invention, inflated to hold water and to be heated by the sun, positioned adjacent to a swimming pool;  
         [0016]      FIG. 6  is a partial cut away view (not to scale) of a water bag embodying the invention and a partial schematic diagram of additional devices for controlling circulation of water into and out of a water bag embodying the invention;  
         [0017]      FIG. 7  is a view (not to scale) of a system embodying the invention; and  
         [0018]      FIG. 8  is a view (not to scale) of a simple water bag for use in systems embodying the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     A water bag  10  embodying the invention may be formed as shown in  FIGS. 1, 1A ,  2  and  2 A.  FIGS. 1 and 1 A show two large rectangular sheets ( 12 ,  14 ) of polyvinyl chloride which may be overlaid on each other to form a pouch (a bag to hold water). In one embodiment, the sheets were 3 feet wide and 18 feet in length and 20 mil thick. It should be appreciated that the length (L) and width (W) of the sheets may vary over a wide range. Likewise, the thickness (t) of each sheet may vary over a wide range so long as the sheet remains pliable and expandable when water is introduced into the pouch. In the manufacture of the water bag, a top sheet  12  may be placed on top of a bottom sheet  14 , of the same general dimensions. The top and bottom sheets ( 12 ,  14 ) are then bonded to each other, at their outer edges, by any suitable bonding means such as heat welding or glue or other bonding means. As shown in the figures, a seam  18  is formed at the outer edges of the sheets which runs along the width and the length (i.e., the entire perimeter) of the water bag. The seam  18  may be formed along a line a distance d 1  from the edges of the sheets (see  FIG. 4A ). Alternatively, the seam  18  may extend for the full distance d 1  from the edges of the sheets to provide a stronger, wider, bond between the two sheets. Along their length, the two sheets define a side identified as  109   a,  at the bottom, and a side identified as  109   b,  at the top. Along their width one side of the two sheets is identified as  108   a  and the opposite side is identified as  108   b.    
         [0020]      FIG. 2  shows that seam  18  is formed along the entire outer perimeter of the water bag  10 . In addition, two openings (orifices)  22  and  24  are shown to be formed on one of the surfaces (e.g., the top) of the water bag. One opening (e.g.,  22 ) is for enabling water to be “inputted” into the water bag and the other opening (e.g.,  24 ) is for enabling the water to be let out of (exit) the water bag. In one embodiment of the invention one and one half (1.5) inch polyvinyl chloride fittings were heat welded into the openings ( 22  and  24 ) of the top layer  12  of the water bag. In  FIG. 2  the intake port  22  and the discharge port  24  are placed at opposite ends of the water bag so that water going into one of the two ports will travel some distance before going out of the other port. As shown in  FIGS. 2 and 2 A (and as further detailed in  FIG. 6 , below,) ribs  20  may be formed to help direct or control the water flow and help make the water bag lay flatter.  FIG. 2A  is intended to illustrate that the ribs  20  may be formed by bonding (joining or connecting) the top and bottom sheets along spaced apart lines to form parallel channels running along the length of the water bag through which the water can flow. The ribs  20  (also referred to as walls, wi, in  FIG. 6 ) may extend (partly or mostly) along the length of the water bag. Alternatively, as shown in  FIG. 6 , the ribs  20  (or wi in  FIG. 6 ) can extend along the length of the water bag, from one side of the water bag (e.g.,  108   a  or  108   b ) close to, but not all the way to, the other side (e.g.,  108   b,    108   a ). A gap (gi) is left at each end to enable water to circulate.  FIG. 2A  also illustrates that, when water is inserted into the pouch  10 , the top sheet tends to be pushed upward and the bottom sheet tends to be pushed downward.  
         [0021]      FIG. 3  is a simplified top view showing a water bag  10  lying alongside a pool  30  of water  32 . The pool  30  may include a filtration system and a pump (not shown) which pumps water out of an output port  34 . An intake (input) hose  36  is connected between the output port  34  of the pool and the input opening  22  of the water bag. An output (discharge or return) hose  38  having an output  40  is connected between the output opening  24  and the pool  30  to direct the water flowing out of the output  40  of hose  38  back into the pool.  
         [0022]      FIG. 4  is a view of a water bag seen from a side showing the water bag  10  when deflated (i.e., when all the water has been removed or evacuated). When the water is removed from within the pocket formed between the two sheets, the top sheet  12  then overlies and rests on the bottom sheet  14  with the weld seam  18  between the two sheets. The hose fittings formed on or about openings  22  and  24  are shown extending vertically up from the top sheet. However, it should be understood that the openings (e.g.,  22 ,  24 ) may be formed on the bottom sheet; and/or one may be formed on the top sheet and one may be formed on the bottom sheet; and/or one or more openings may be formed along or about the seam  18 .  
         [0023]      FIG. 4A  is an expanded view of an end region of the top and bottom sheets ( 12  and  14 ) with the seam weld  18  binding the two sheets. The thickness t 2  and t 3  of the two sheets  12  and  14  may be the same, but need not be so. The seam  18  may terminate a distance d 1  before the outer edge of the sheets, or extend all the way. Where the seam ends a distance d 1  before the outer edge, the distance d 2  is negligible since the sheets will tend to lie on top of each other.  
         [0024]      FIG. 4B  is intended to show that when the water bag  10  is emptied of water it can be easily rolled up for storage or for moving the bag from spot to spot. Alternatively, the water bag  10  could be folded upon itself for storage or for moving.  
         [0025]      FIG. 5  is a partially isometric view of the water bag  10  in an inflated condition with input hose  36  attached between output port  34  of the pool  30  and input opening  22  of the water bag. Water is pumped from port  34  through intake hose  36  into the water bag  10  and inflates the water bag; causing the water bag to expand. The water pumped into the water bag gets heated by solar radiation and then flows out via output opening  24  and output (discharge) hose  38  back into the pool  30 . That is, the pressure from the pump (not shown) forces the water to flow through the return hose  38  back into the pool  30 , as illustrated by the arrows in the figure.  FIG. 5  also shows that the rays  58  of the sun incident on the water bag are absorbed by the water bag and are used to heat the water as it flows through the water bag  10 . Note that the material used to form the water bag as well as the color (generally dark) of the water bag  10  are specifically selected to ensure maximum absorption of the solar radiation incident on the water bag, in order to best heat the water contained in the bag.  
         [0026]      FIG. 6  is a cut away view of a solar heating system which includes a water bag or pouch  10 . The water bag  10  shown in  FIG. 6  is rectangular in shape having a front end  108   a,  an opposite, back, end  108   b,  a front side  109   a,  and an opposite, back, side  109   b.  As discussed above, two sheets of a pliable non-porous (impermeable) material (e.g., plastic, rubber or canvas) which can hold water are bound or seamed together at their outer edges to form the water bag  10 . In  FIG. 6 , the water bag has an input port  22  to enable water to be inserted into the water bag  10  and an output port  24  to let out water heated within the bag.  
         [0027]     In  FIG. 6 , the water bag is ribbed, or seamed, to form intermediate interior walls (e.g., w 1 -w 7 ) which define a multiplicity of channels or paths (e.g., C 1 -C 8 ). The walls, wi, extend along the length of water bag, but not for the full length. There is a gap (gi) between each wall, (wi), and one end of the water bag (e.g.,  108   a,    108   b ). In  FIG. 6 , the walls starting at end  108   a  of the water bag extend close to, but not all the way, to the other end  108   b.  There is a gap (e.g., g 1 , g 3 , g 5  and g 7 ) between the end of each wall and the other end  108   b  of the water bag. Likewise, the walls starting at end  108   b  of the water bag extend close to, but not all the way, to the other end  108   a.  There is a gap (e.g., g 2 , g 4 , g 6 ) between the end of each wall and the other end  108   a  of the water bag. The openings or gaps (gi) between the end of each wall wi and the corresponding side ( 108   a,    108   b ) of the water bag allow water to flow from one channel (e.g., C 1 ) to the next channel (e.g., C 2 ). Thus, there are openings gi between the walls wi and the side  18   a  of the water bag to allow water to flow from one channel (e.g., C 2 ) to the next channel (e.g., C 3 ). So configured water can be pumped and flow from the pool of water  30  via tubing (hose)  36   a  and  36   b  into input port  22 . The water can then flow along the channels (e.g., C 1 -C 8 ) formed within the water bag until the water reaches output port  24 . The water can then flow from output port  24  via tubing  38   a,    38   b  back into the pool of water.  
         [0028]     As the water flows through the channels from input  22  to output  24 , it is subject to being heated by the solar heat absorbed by the water bag.  
         [0029]     The system may be operated in several different modes. In one mode, a water pump  105  (which may be a pump integral to the water circulation and filtration system of the pool or an additional, independent, pump specifically used with the water bag of the invention) pumps water from the pool via hose  36   a  and into the water bag via hose  36   b  and the water flows continuously through the water bag  10  and is then returned to the pool of water via hoses  38   a,    38   b.    
         [0030]     In another mode of operation, a valve  107  may be inserted between the output port  24  of the bag and the pool of water. In  FIG. 6 , the input side of valve  107  is shown connected to port  24  via hose  38   a  and the output side of valve  107  is connected to the pool via hose  38   b.  The valve  107  may be selectively activated (manually or thermostatically) to prevent the water in the bag from flowing out continuously. Rather, the valve may be selectively shut to prevent the flow of water out of the bag until the water in the water bag has been heated for a period of time or until it reaches a certain temperature. This may be accomplished manually or automatically An important aspect of the invention is the ability to deflate the water bag such that it is easily foldable and/or rolled up. To this end, optional, selectively enabled output ports (O 1 -O 4 ) are shown formed adjacent to the side  108   b  of the water bag to enable the water in the water bag to be drained more quickly and effectively.  
         [0031]     Thus, when the water bag is to be folded, tubes  36   b  and  38   a  may be detached from the input port  22  and the output port  24 , respectively. Any water within the water bag  10  can then be evacuated by causing the water to exit through ports  22  and  24 . In addition, if optional ports (e.g., O 1 -O 4 ) are formed in the water bag, they may be activated (opened) to empty out the water in the water bag. Obviously, when the bag is in use the optional ports would normally be closed.  
         [0032]     The materials used for the top and bottom sheets  12  and  14  can vary so long as they have similar characteristic to polyvinyl chloride and achieve similar results after construction; e.g., the ability to absorb solar energy, inflate and deflate with water pressure, and to be rolled or folded tightly. The thickness of the top and bottom sheets can also vary over a wide range so long as the desired results noted above are achieved.  
         [0033]     Seams and ribs ( 20  and wi) of the type detailed in  FIG. 6  and the other figures may be heat welded, sewn or glued. By way of example, canvas material may be used which can be sewn or glued. The shape and size of the water bag may vary widely.  
         [0034]     The openings (e.g.,  22 ,  24 ) and the fittings for the openings can vary in size and in the type of materials used.  
         [0035]     The hoses (e.g.,  36 ,  38 ) may vary in length and diameter and in their termination. For example, male or female plug-in or threaded hoses may be used. Intake and/or output hoses may also be permanently connected to the water bag.  
         [0036]     As shown in  FIG. 6 , a valve  107  may be added to the output (discharge) hose to control water flow. A valve  108  may also be added to the intake hose to control the flow of water into the water bag.  
         [0037]     In  FIGS. 1-5  the water pump used to pump water into the pool is also used to cause water to flow into the water bag. Alternatively, an external water pump could be used to cause water to flow into the water bag as shown in  FIG. 6 .  
         [0038]     In  FIG. 7 , a filter system pump  115  and a filter  117  which may be integral to the swimming pool  30 , or independent thereof, may be used to either pump water via hose  361  into the pool  30  or via hose  36   a  and valve  108  and hose  36   b  into the water bag  10 . In  FIG. 7 , the water bag  10  includes an intake tube (¾ inch hose) which is formed along one side ( 108   a ) of the bag  10  and which would have different sized holes (h 1 -h 4 ) distributed along sections of the tube to control the flow of water into the water bag. The water in the bag may be discharged via a discharge hose which empties into the pool  30  via hoses  38   a,  valve  107  and tube  38   a.    
         [0039]      FIG. 8  shows a simple water bag embodying the invention where an intake or discharge tube,  36  or  38 , is inserted into an opening between the two sheets  12 ,  14  whose outer perimeter is bonded to form a pouch.  
         [0040]     In the figures, the invention has been illustrated using a swimming pool in conjunction with the water bag. It should be understood that this is for purpose of illustration only, and that any pool of water such as a spa or pond may be used in conjunction with a water bag embodying the invention to use solar heat to warm up water introduce into the water bag which can then be discharged into the pool of water.

Summary:
A solar heating system for heating a pool of water includes a water bag formed of materials such that when it is not in use, it is deflated and compressed so as to occupy little space. When the water bag is in use it is inflatable and expandable so as to contain a substantial amount of water which can be heated by the rays of the sun absorbed by the water bag. A water bag embodying the invention can be formed of inexpensive materials (e.g., plastic, rubber or canvas). The water bag is very portable and can be set up (to collect water and heat it) quickly and easily. When not in use it can be folded or rolled up taking up very little storage space. It does not interfere with the use of the pool of water it is intended to warm. It can be set up any place, close to the pool of water or by using longer hoses it can be located away from the pool, where the best sunlight and solar heat is available.