TECHNICAL FIELD

The present invention relates to a photovoltaic solar panel comprising solar cells laminated with an encapsulant material· between a transparent layer and a transparent/non-transparent layer, and a heat transfer layer provided to transfer the heat of the solar cells and to the manufacture method there of.

BACKGROUND OF THE INVENTION

The photovoltaic solar panels used for transforming the solar energy into the electrical energy are well known in the art. A photovoltaic solar panel mainly comprises a top layer made of a material like glass and being capable of effectively transmitting the sunlight, the solar cells arranged below it and being typically silicone based, and a back layer located below this solar cells, increasing the resistance of the panel against various external impacts and against corrosion and typically made of a polymer based material. Said layers constitute an integrated panel by being laminated to each other through an encapsulant material such as EVA.

Recently, the panels on which a glass layer is applied instead of the polymer based back layer have not been popular in the market. Such panels are known as“glass- glass” panels and they present more resistant features relative to the prior art panels comprising polymer based back layer, and since they are transparent, they also have and advantage of enabling the sunlight to enter the interior sites of the architectural buildings for which they are used.

Each increase of 1 °C to occur at the cells of such types of photovoltaic panel may reduce the panel efficiency from 0.2 to 0.5%. Although the manufacture of photovoltaic panels is widespread, the fact that the material life and efficiencies of these panels decreases with increasing temperatures leads to the losses in the systems to produce electricity from the sunlight. It is known that it is possible to reduce the temperature of the photovoltaic (PV) module part by means of a circulating fluid or by the air. Therefore, as an alternative to the usage of PV modules alone, there have recently been studies conducted on the hybrid PV/Thermal (PV/T) systems which are capable of producing both electrical and thermal energy and used together with the cooling systems of the PV module.

For example in US 5,522,944, a PV/T type solar energy transformation module is disclosed which comprises a series of photovoltaic cells disposed to transform solar energy into the electrical energy in a substantially insulated frame and the thermal collector pipes connected to each other so as to be at the same surface with these photovoltaic cells.

EP 1 873 843 discloses a hybrid PV/T type solar energy transformation module, comprising a series of photovoltaic cells laminated with glass, EVA and a thin film and disposed to transform solar energy into the electrical energy in an insulated frame and the thermal pipes optimized with various materials and shapes, and being connected to the heat-exchanger surface.

JP 2002039631 comprises a hybrid PV/T type solar energy transformation module in which the surface sealing is provided below the transparent front glass and in an insulated frame and the contact of the photovoltaic cells to the water pipes is enabled by adhering with the materials having high heat conductivity in order to provide o good heat conductivity.

DE 19809883 discloses a hybrid PV/T module, having a series of photovoltaic cells interposed between PVF (Tedlar®) and EVA layers and a fluid system integrated to transfer the heat over these photovoltaic cells.

The conventional PV panels do not present an effective proposal for the problem of efficiency which is reduced by the increasing temperature. This is the case with both independent usages of the PV module and the integrated usages thereof with a thermal module (i.e. PV/T panel). Also, it cannot be figured that the thermal stresses created between the units are suitably tolerated and the PV modules being appropriate for the hybrid collector (PV/T) manufacture presents adequate resistance features against the mechanic forces. DESCRIPTION OF THE INVENTION

The object of the present invention is to provide an effective photovoltaic solar energy conversion panel.

A further object of the invention is to provide an effective photovoltaic/thermal energy conversion panel.

Another object of the invention is to allow for increasing the efficiency of the photovoltaic/thermal energy conversion panel having been already used or being presently in use.

In order to meet the object, the invention relates to a sandwich type photovoltaic solar panel comprising a first transparent layer provided at the top portion, a first encapsulant layer provided below the first transparent layer, plurality of solar cells provided below the first encapsulant layer, a second encapsulant layer provided below the plurality of solar cells, a second layer provided below the second encapsulant layer, and this is characterized by comprising a third encapsulant layer provided below the second layer and a heat transfer layer below the third encapsulant layer.

According to an embodiment of the invention, the panel comprises a protective layer provided below the heat transfer layer and a fourth encapsulant layer between said layers.

According to an embodiment of the invention, the second layer may be selected from a transparent material. According to an embodiment of the invention, the second layer may be selected from a non-transparent material.

In another aspect, the invention comprises a hybrid photovoltaic/thermal module including a thermal module integrated with the photovoltaic module having the features described above.

According to an embodiment of the invention, at least one of the encapsulant layers is selected from a group consisting of Ethylene Vinyl Acetate (EVA), Polyvinyl Butyral (PVB), and Polyolefin (PO). DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates a representative and exploded perspective view of the layers of the sandwich type photovoltaic solar energy conversion module.

Fig. 2 illustrates the perspective view of the installed state of the module in Fig. 1.

Fig. 3 is the front view of Fig. 2. REFERENCE NUMERALS OF THE COMPONENTS IN THE DRAWINGS

1. Protective layer

2. Fourth encapsulant layer

3. Heat transfer layer

4. Third encapsulant layer

5. Second layer

6. Second encapsulant layer

7. Solar cell

8. First encapsulant layer

9. First transparent layer

DETAILED DESCRIPTION OF THE INVENTION

The sandwich type photovoltaic solar panel of the invention may basically be in the form of a rectangular parallelepiped. At the top of this, a first transparent layer (9) is provided. Said first transparent layer (9) is preferably made of a glass material having the feature of transmitting light more than 90% and its thickness may preferably vary between 2 to 4 mm. Said first transparent layer (9) may be provided with various material features. For example, it may comprise a low amount of iron (e.g. up to 0.02% by weight) and have a low light-reflecting property; for example it may comprise an anti-reflective. Still, said first transparent layer (9) may be tempered or half tempered. The first transparent layer (9) may be provided with various refractive and/or diffractive properties so as to change the diffraction of the sunlight, for example, it may be supported by various lenses. The first encapsulant layer (8) is provided below the first transparent layer (9) so as to cover the bottom thereof. A plurality of solar cells (7) is provided below the first encapsulant layer (8) based on the panel sizes. The solar cells (7) may be in the forms of poly or mono PERC, or the derivatives thereof. The second encapsulant layer (6) is provided below the solar cells (7) so as to cover the bottom surfaces thereof.

A second layer (5) is provided below the second transparent layer (6) so as to cover the bottom surface thereof. Said second layer (5) may be made of a glass material having a light reflectivity preferably between 77% and 89%, for example it may be painted with a dying element increasing the reflectivity. The thickness of the second layer may vary between 2 and 4 mm. Said second layer (5) may be provided with various material features. For example, it may comprise 0.02 to 0.1 % iron by weight while said second layer (5) may be tempered or half tempered. The third encapsulant layer (4) is provided below the second layer (5) so as to cover the bottom thereof. The heat transfer layer (3) which is made of preferably copper, but also of aluminum or stainless steel, which is small relative to the cell sizes and has a thickness varying from 0.1 to 1 mm is provided below the third encapsulant layer (4). The heat transfer layer (3) is preferably in the form of a metal strip and contributes to the transfer of the created heat generated on the solar cells (7).

According to an embodiment of the photovoltaic solar panel of the invention, a protective layer (1 ) is provided below the second layer (5) and at the base portion of the panel. This protective layer (1) may be made of preferably a composite material, for example, Tedlar®-Polyester- Tedlar® (TPT); Tedlar®-

Polyethylene terephthalate (PET)-EVA (TPE). The protective layer (1 ) functions as a mesh and allows the heat transfer layer (3) to be adhered to the second layer (5) for a longer time period and in a more effective manner. On the other hand, the protective layer (1 ) may reduce the losses of the heat absorbed from the solar cells (7) by the heat transfer layer (3). A fourth encapsulant layer (2) is arranged between the second layer (5) and the protective layer (1 ).

The encapsulant mentioned above provides the adhesion between the other layers described. The encapsulant layers may be produced of one of the Ethylene Vinyl Acetate (EVA), Polyvinyl Butyral (PVB), and Polyolefin (PO) known in the art. According to an embodiment of the invention, all encapsulant layers may be made of the same material, also one or more than one layer(s) may be made of a certain material such as EVA, while any other encapsulant layer is made of another material such as PVB. The encapsulant layers may be resistant to high temperature and high ultra-violet lights, transparent or dyed, or have the low thermal resistance.

The connection of the layers constituting the photovoltaic solar panel of the invention is provided by the lamination process and preferably by vacuum lamination. Therefore, the vacuum laminators divided from each other by the elastic membranes within the vacuum chambers known in the art. The lamination process may be performed in the range of 120-180°C and between 12 and 20 minutes based on the material of the encapsulant used.

In the photovoltaic solar panel of the invention, since the solar cells are arranged between the first transparent layer (9) and the second layer, these cells are enabled to be protected from the external effects and to gain resistance, particularly when it is made of glass. Also, the risk of electric leakage is prevented which may be occur in the photovoltaic solar panel, by using glass material. Moreover, since the thermal conduction coefficient of the glass is more than that of other photovoltaic module layers, it contacts solar cells and enabled to better transfer the heat to the subsequent layer.

During the manufacture of the sandwich type photovoltaic solar panel of the invention, firstly the first transparent layer (9) is placed, the first encapsulant layer (8) is placed thereon, a plurality of solar cells (7) are placed on the first encapsulant layer (8), the second encapsulant layer (6) is placed after that, the second layer (5) is placed on the second encapsulant layer (6), the third encapsulant layer (4) is placed after that, and the heat transfer layer (3) is placed on the third encapsulant layer (4).

According to an embodiment of the invention, the fourth encapsulant layer (2) is placed on the heat transfer layer (3), the protective layer (1 ) is placed on the fourth encapsulant layer (2), and said layers are combined at a time together or separately at an appropriate lamination temperature and by being treated with the lamination process. The sandwich type photovoltaic solar panel of the invention may be manufactured together with a thermal module or may be integrated with a thermal module which has already been in use. Thus, a hybrid PV/T type panel may be obtained. For example, the thermal module may be part of a PV/T panel such as the one described in US 20130160821. In this case, a pipe may be provided which is combined (for example welded) at the lower surface of the heat transfer layer (3) wherein a liquid or air fluid passes through it.