Patent Publication Number: US-2016238281-A1

Title: Device for stiffening and sealing a solar collector

Description:
FIELD OF APPLICATION 
     The present invention relates to solar collectors, in particular a device for stiffening and sealing a solar collector that can be used to heat water in household systems, industrial processes and swimming pool climatization. 
     BACKGROUND 
     As published by EUROBSERV&#39;Er in May of 2012, during 2011 only in Europe over 39 million m 2  of solar collectors were installed allowing to obtaining an annual thermal power above 27 GWh. This power is comparable with that annually produced by an average nuclear power station. As to flat panels, the use of solar collectors exceeds 84% of the total volume of the market. 
     A conventional solar collector includes the following elements:
         Solar panel with a black absorption layer;   A system to transfer heat from the absorption layer to the water to be heated;   Box to locate the solar panel;   Transparent screen, generally made of glass, allowing solar irradiation to the solar panel and the creation of greenhouse effect;   Thermal insulation to prevent loss of heat on the collector side towards the supporting casing.       

     The solar panels are made of aluminum or copper plates. On one side, there is the black absorption layer, while on the other side there is a copper tube coil or a system of parallel copper tubes touching the solar panel, where they join tubes for the inlet of cold water and the supply of hot water. The heat is transferred by thermal conductivity from the solar panel to the water; thus, the preferred material is copper. The collector comprises thermal insulation as fiberglass or foam material. 
     The return period of investments is of 15 years. The extruded flat solar collector is the simplest to manufacture and its manufacture involves lower cost. The materials for normal solar collectors are relatively expensive and their manufacture is hard, since they weigh too much; this makes assembly and maintenance complicated. Document MX 2011002911 describes a double-side thermal solar panel comprising a vacuum tight enclosure, which in turn has a first and second glass plate, a perimeter frame defining the lateral surface of the enclosure, where the solar panel at least has a first heat absorbent, a second heat absorbent, a pipe entering and leaving the casing going through the first and second heat absorbents, and a box-shaped element surrounding the pipe. Although this document deals with a technical issue similar to that of the invention—consisting in a modular, easy- and fast-to-manufacture construction system—the system that allows sealing the plate is made up of vacuum glass plates. The document does not disclose a device that allows insulation at the inlet-outlet of fluid and it does not correspond to a flat absorber attached to a fluid inlet-outlet collector. 
     Document ES8205364 describes a process to manufacture a heat absorption plate comprising a number of parallel tubes joined by jumpers going from each tube in opposite directions. Said process consists in arranging a number of parallel tubes in certain places of the panel; the tubes are tightly joined on the edges of joining jumpers placed on each side of each tube. The tubes are also tightly joined by the ends with the collecting tubes placed on the two opposing edges of the absorption plate. The document describes a solar panel with a plurality of pipes placed parallel each other, which are in turn tightly connected to collecting tubes on their ends. The document shows that the joints between tubes and collectors are tight, where each tube is inserted in the collector and joined by welding; therefore, it does not show an external device to perform such sealing. 
     Document U.S. Pat. No. 4,239,035 describes a solar heating method, in which a fluid is heated by a panel with upper and lower surfaces defining a number of channels through which the fluid goes through. The solar panel has an inlet collector and an outlet collector connected to the plate through a notch comprising a gluing portion between said collectors and the plate. Although this document describes a solar panel with its headers joined to the panel through a notch, it does not show an external device performing the single function of sealing the joining between said headers and the panel. In addition, the joining between the headers and the panel is performed through an adhesive, which is little efficient due to said material degradation and the problems this kind of joining can have over time; this would reduce the efficiency of sealing. 
     Document US2009095282 contains a solar panel comprising two parallel, but spaced apart panels, where each panel has a front surface, a back surface and left and right side edges. In the space between the panels there are several internal walls arranged defining conduits for the circulation of the fluid. The lateral edges of the solar panel join to tubular members having a joining notch to said panel. The document describes a solar panel where the inlet and outlet collectors of fluid are made in the form of a tube with a notch, so that to join to the solar panel. The sealing of joining between said collectors and the panel is achieved by using adhesive or glue in the area, which—as in the previous case—also degrades over time and loses efficiency. 
     TECHNICAL PROBLEM 
     There is the need of having a device to increase sealing and stiffness of a solar collector m order to reduce losses in the joining between the headers of fluid inlet and outlet and the heating plates. 
     TECHNICAL SOLUTION 
     In order to solve said problem, a device is arranged for the sealing and stiffening of a solar collector, comprising a supporting profile to stiffen an extruded flat absorber and the fluid inlet-outlet collector, formed by open cylinder modules with two parallel plates and a tray, preferably of plastic reinforced with glass fiber for the sealing of the connection of the extruded flat solar absorber and the fluid inlet-outlet collector, so that to keep said elements as a common element. 
     The solution proposed allows increasing the reliability of the thermal solar collector by increasing its sealing capacity and reducing the collector losses; it simplifies the manufacture process by being made up of easy-to-assemble parts each other that make up a single system. This results in reduced manufacturing costs. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
         FIG. 1  is a perspective view of a device for stiffening and sealing according to an embodiment of the invention. 
         FIG. 2  is a perspective view of a stiffening device without its reinforced plastic tray according to an embodiment of the invention. 
         FIG. 3  is a perspective view of the assembly of a device for stiffening and sealing of a solar collector. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to a device for stiffening and sealing a thermal solar collector. Said device comprises a supporting profile ( 1 ) for stiffening and sealing the joining of a flat extruded absorber ( 4 ) and collectors of fluid inlet-outlet ( 2 ) formed by open cylindrical modules with two parallel plates, and a tray ( 5 ), preferably of plastic reinforced with fiberglass for the sealing of the connection of the flat extruded solar absorber and of collector of fluid-inlet-outlet, so that to keep said elements as a common element. 
       FIGS. 1 and 2  show a supporting profile ( 1 ) for the stiffening of an assembled unit of a solar flat absorber ( 4 ) and collectors of fluid inlet-outlet ( 2 ), where said supporting profile ( 1 ) is formed by open cylindrical modules with two parallel plates. The supporting profile ( 1 ) allows joining the solar flat absorber ( 4 ) and the collectors of fluid inlet-outlet ( 2 ) in one piece. In the thermal solar collector two collectors of fluid ( 2 ) are used: an inlet fluid collector and an outlet fluid collector. The design of these collectors ( 2 ) is the same. Each collector includes a notch ( 3 ) or central well, from which the solar flat absorber is projected. 
       FIG. 3  shows the tray ( 5 ), preferably of reinforced plastic, which—in the preferred embodiment of the invention—includes epoxy resin and fiberglass. The reinforced plastic ensures the sealing of the extruded solar flat absorber ( 4 ) and of fluid collectors ( 2 ). Another function of the reinforced plastic tray ( 5 ) is the creation of the supporting unit of the extruded thermal solar absorber and of fluid collectors. 
     The present invention is characterized by comprising a supporting profile ( 1 ) and the reinforced plastic tray ( 5 ) for the stiffening and sealing of the extruded solar flat absorber ( 4 ) and collectors of fluid inlet-outlet ( 2 ). The extruded solar flat collector is made up of the thermal solar absorber assembly ( 4 ), the fluid inlet collector ( 2 ) for cold water to enter the solar collector, and the fluid outlet collector ( 2 ) for hot water to leave the collector. The thermal solar absorber ( 4 ) is manufactured from a flat extruded panel in the form of flat tube with multi-channels. 
     The collectors of fluid inlet-outlet ( 2 ) have a notch ( 3 ) along the collecting tube. The width of the notch ( 3 ) is the same as the thickness of the extruded flat panel ( 4 ), and the length of the notch is the same as the width of the extruded flat panel ( 4 ). The flat extruded solar absorber ( 4 ) joins the respective collectors of fluid inlet-outlet ( 2 ) through the notch ( 3 ). 
     Once the extruded flat solar absorber ( 4 ) joins the collectors of fluid inlet-outlet ( 2 ) the supporting profile ( 1 ) is installed and sealing is performed with the reinforced plastic tray ( 5 ): on the two parallel plates of the supporting profile a layer of epoxy resin is placed, as well as the fiberglass in order to strengthen the joining sealing of the flat extruded panel ( 4 ) and the collectors of fluid inlet-outlet ( 2 ). 
     Thus, the collectors of fluid inlet-outlet ( 2 ), the thermal solar absorber ( 4 ), the supporting profile ( 1 ) and the plastic tray reinforced with fiberglass ( 5 ) make up an assembly of just one system. In this way, a monolithic piece is obtained. The extruded flat solar collector is obtained without welding seams or glue. 
     EXAMPLES OF EMBODIMENTS 
     In a first embodiment of the invention, as observed in  FIGS. 1 to 3 , the extruded thermal solar collector comprises a fluid inlet collector ( 2   a ), a fluid outlet collector ( 2   b ), a thermal solar absorber ( 4 ), a supporting profile ( 1 ) and a plastic tray ( 5 ) reinforced with fiberglass. The thermal solar absorber ( 4 ) shows a polycarbonate flat extruded tube with multi-channels of the same thickness as the panel, preferably with a thickness of 8 mm, a width of 80 cm and 2 m long. The collectors ( 2 ) of fluid inlet-outlet and the tube of collectors ( 2 ), which material is preferably polycarbonate, have a thickness of 3 mm, 50 mm diameter and 90 cm long. 
     The extruded solar flat absorber ( 4 ) connects to the collectors of fluid inlet-outlet ( 2 ) through the notch ( 3 ), which width is 8 mm. Over the fluid inlet collector ( 2   a ) and over the fluid outlet collector ( 2   b ), the polycarbonate supporting profiles ( 1 ) are installed, preferably of 2 mm thickness and a profile width of 80 cm. 
     Then, the supporting profile ( 1 ) is installed and sealing is performed with the plastic reinforced tray ( 5 ): over the two parallel plates of the supporting profile ( 1 ), a layer of epoxy resin and fiberglass is placed. The thickness of reinforced plastic of epoxy resin and the fiberglass is of 4 to 6 mm. 
     In a second embodiment of the invention, the thermal solar absorber ( 4 ) shows a polycarbonate extruded flat tube with multi-channels; the panel thickness is of 10 mm, the width 100 cm and the length 3 m. In addition, the thermal solar absorber ( 4 ) shows a black coverage of acrylic paint. The collectors ( 2 ) of fluid inlet-outlet show a PVC extruded tube with a notch ( 3 ) of 100 cm length and the PVC collector tubes ( 2 ) of 2 mm thickness, 50 mm diameter and 110 cm length. 
     The extruded solar flat absorber ( 4 ) connects to the collectors of fluid inlet-outlet ( 2 ) through the notch ( 3 ), which width is 10 mm. Over the fluid inlet collector ( 2   a ) and over the fluid outlet collector ( 2   b ), PVC supporting profiles ( 1 ) are installed of 2 mm thickness and 100 cm width. 
     Then, the supporting profile ( 1 ) is installed and the plastic reinforced tray ( 5 ) is sealed: over the two parallel plates of the supporting profile, a layer of epoxy resin and fiberglass is placed. The thickness of reinforced plastic of epoxy resin and the fiberglass is of 2 to 4 mm. 
     LIST OF REFERENCE SIGNS 
     ( 1 ) Supporting profile 
     ( 2 ) Collectors of fluid inlet-outlet (with a notch) 
     ( 2   a ) Inlet collector 
     ( 2   b ) Outlet collector 
     ( 3 ) Notch 
     ( 4 ) Extruded flat absorber with multi-channels 
     ( 5 ) Plastic reinforced tray