FIELD OF THE INVENTION
[1]
The present invention relates to solar panels and, in particular, to an insulated solar panel for supplying heated, recirculated water to a swimming pool.
BACKGROUND OF THE INVENTION
[2]
Swimming pools may be heated by recirculating pool water through one or more solar panels made of black rubber tubing or the like laid on a roof and exposed to the sun and other elements. Rubber and, to a lesser extent, plastic are the materials of choice for the tubing as they are resistant to corrosion by salt carried in the pool water and, unlike copper tubing, do not leave a stain in the pool. However, in order to effectively heat an average pool, the surface area of solar panelling required should, according to Australian Standards, be 70% of the total surface area of the pool. For instance, if an average pool has a surface area of 40 m 2 , then the surface area of solar panelling required to be installed on a roof will be 28 m 2 . This is a relatively large proportion of the roof devoted to supporting solar panelling for a pool, and may be unsightly and problematic to maintain. Furthermore, such a large surface area of solar panelling, being exposed to the elements, may deteriorate over time and, particularly where the solar panelling is made of rubber, is a target for cockatoos and some other birds who enjoy pecking at, or even eating, the rubber material. Still further, the exposed solar panelling may be subject to the cooling effects of wind or frost, thereby prolonging the time required for the water recirculating through the tubing to attain the desired temperature.
SUMMARY OF THE INVENTION
[3]
It is, therefore, an object of the present invention to overcome, or at least substantially ameliorate, the shortcomings and disadvantages of the prior art.
[4]
According to the invention, there is provided a solar panel comprising tubing through which water from a swimming pool is recirculated, the tubing being adapted to be exposed to the sun for heating the water to a temperature whereby the pool is heated, and a housing for the tubing, the housing having a transparent screen covering the tubing, the arrangement being such that the housing retains heat therewithin for increasing the temperature of the tubing above that outside the housing.
[5]
Preferably, the solar panel further includes a tubular member having a header portion and opposed end portions, the header portion being located within the housing and each end portion protruding outwardly from a respective side wall of the solar panel so as to define an opening at the side wall, the end portions being in liquid flow communication with the header portion, and the header portion being in liquid flow communication with the tubing so that heated, recirculating water passing through the tubing may exit the solar panel through a first said opening and unheated, recirculating water passing through a second said opening may enter the solar panel for heating.
[6]
It is preferred that the solar panel further includes a key extending outwardly from each end portion and a key way formed continuously with a hole in a respective side wall through which the tubular member passes, the key being engaged within the key way.
[7]
In a preferred form, the solar panel further includes a circlip which is removably located circumferentially around each end portion so as to space apart a barrel union from the respective side wall, the barrel union being adapted to engage the end portion.
[8]
The transparent screen is preferably made of dear acrylic or toughened glass.
[9]
The solar panel preferably includes insulating material located within the housing and upon which the tubing is supported.
[10]
The tubing may be made of EPDM rubber or PVC plastic.
[11]
According to another aspect of the invention, there is provided a solar panel assembly for a roof comprising a plurality of the solar panels described above, each one of the solar panels having a barrel union fitted thereto for allowing recirculating water to pass from the tubing in one solar panel to the tubing in an adjacent solar panel.
SUMMARY OF THE DRAWINGS
[12]
Fig. 1 is a perspective view of an assembly of solar panels according to a preferred embodiment of the invention mounted to a roof. Fig. 2 is a perspective view of an isolated solar panel from the assembly shown in Fig. 1 . Fig. 3 is a sectional side view through III-III of the solar panel shown in Fig. 2 . Fig. 4 is a sectional end view through IV-IV of the solar panel shown in Fig. 2 . Fig. 5 is an exploded perspective view of the solar panel shown in Fig. 2 and external tubing therefor. Fig. 6 is a top view of the solar panel assembly shown in Fig. 1 illustrating the direction of flow of recirculating water. Fig. 7 is an exploded perspective view of a solar panel according to another preferred embodiment of the invention and external tubing therefor. Fig. 8 is a perspective view of a cooperating arrangement at a corner region of the solar panel of Fig. 2 or Fig. 5 at a first stage of assembly. Fig. 9 is a perspective view similar to that of Fig. 8 but showing the cooperating arrangement at a second stage of assembly. Fig. 10 is a perspective view similar to that of Figs. 8 and 9 but showing the location of the key and key way of the cooperating arrangement after installation and when the tubular member of the solar panel has expanded due to extreme heat.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF INVENTION
[13]
The solar panel 10 shown isolated or as part of an assembly of solar panels in Figs. 1 to 6 includes ethylene propylene diene (EPDM) rubber tubing 12 (although polyvinylchloride (PVC) plastic tubing may alternatively be used) formed as a mat and providing a passageway for recirculating water from a swimming pool that is desired to be heated by heat radiating from the sun and impacting on the solar panel when mounted on a roof.
[14]
The tubing 12 is surrounded by a housing 14. The housing 14 includes, in this embodiment, a transparent screen 16 covering the tubing 12, and which is made of dear acrylic (although toughened glass may alternatively be used).
[15]
The solar panel includes insulating material 18 located within the housing 14 (see especially Fig. 5 ) and upon which the tubing 12 is supported.
[16]
The housing 14 further includes an aluminium tray 20 (although a polypropylene tray may alternatively be used) upon which the insulating material 18 is supported, and a rubber seal 22 between the transparent screen 16 and the tray 20. Rubber straps are used to press the tubing 12 against the insulating material 18 without causing any blockage of the recirculating water passageway.
[17]
A set of aluminium clamps 24 are used to clamp together the transparent screen 16 and the tray 20 along the rubber seal 22.
[18]
A plurality of the solar panels 10 are interconnected to form an assembly of solar panels which are mounted to a roof as shown in Figs. 1 and 6 . The solar panels…
