ITTO20080859A1 - GENERATOR UNITS WITH PHOTOVOLTAIC CELLS - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

"PHOTOVOLTAIC CELL GENERATOR GROUP"

The present invention relates to a photovoltaic cell generator unit.

In the field of the production of electrical and thermal energy by means of photovoltaic cells it is known to use photovoltaic solar panels directly exposed to sunlight or on which the sun itself is directed by means of suitably oriented flat specular bodies.

Known photovoltaic solar panels have extensions which are proportional to the amount of energy to be produced and, in general, therefore, with the exception of particularly low powers, known photovoltaic solar panels normally have significant extensions, even of several square meters. Their use is therefore subject to the availability of considerable spaces that are difficult to find especially in urban environments if not exploiting roofs or side brushing of buildings. In any case, the known solar panels, once the practical installation difficulties resulting from the aforesaid location have been overcome, are often difficult to reach for normal control and maintenance operations.

In addition to what has been disclosed up to now, known solar panels often entail problems of environmental impact.

From a construction point of view, known photovoltaic solar panels, on the other hand, have relatively high costs attributable, on the one hand, to the considerable quantity of photovoltaic cells used, that is to the considerable extension of the photovoltaic surface of incidence of solar rays and, on the other hand, , to the assembly and electrical connection costs of the photovoltaic cells to each other.

The purpose of the present invention is to provide a generator unit with photovoltaic cells, which allows the above problems to be solved in a simple and economical way and, in particular, is simple and economical to produce, as well as compact and easy to install and maintain. .

According to the present invention, a photovoltaic cell generator unit is provided comprising a support arm and a photovoltaic cell device carried by said support arm and comprising at least one photovoltaic surface of incidence of a light radiation, characterized in that it further comprises a parabolic reflecting body carried by said support arm and generating a light beam having its own optical axis and converging at a focal point, and by the fact that said photovoltaic cell device comprises input means for said light beam arranged in a position facing the said parabolic body is along said optical axis and a cooling circuit of said incident photovoltaic surface; the said cooling circuit using an electrically insulating and coolant liquid.

The invention will now be described with reference to the attached drawings, which illustrate a non-limiting example of embodiment, in which:

Figure 1 is a perspective view of a preferred embodiment of the photovoltaic cell generator unit according to the present invention;

Figure 2 illustrates, on an enlarged scale, a detail of Figure 1;

Figure 3 is a perspective view of a component of the detail of Figure 2;

Figure 4 is a figure similar to Figure 1, and illustrates a variant of a detail of Figure 1; and Figure 5 illustrates, on an enlarged scale, a detail of Figure 4.

In Figure 1, 1 indicates a parabolic generator unit with photovoltaic cells comprising a support structure 2, in turn, comprising an attachment plate 3 and a support arm 4 extending upwards from the same plate 3. The unit 1 also comprises a parabolic body 5, which is connected to an upper end of the arm 4, has, in the particular example described, dimensions comparable to those of traditional parabolic bodies for civil use for receiving signals from satellites, and is frontally delimited by a specular parabolic surface 6, conveniently chromed, suitable for generating a light beam having an optical axis and converging at a focal point. With specific reference to Figure 1, the front surface 6 is constituted by a plurality of flat portions 6a arranged side by side and bounded perimeter, each one, by a respective broken line.

Still with reference to Figure 1, the unit 1 also comprises a further support arm 8, which extends overhanging from a perimeter edge of the parabolic body 5 and supports a photovoltaic cell device 10.

With reference to Figure 1 and, in particular, to Figure 2, the device 10 comprises a tubular body 11 connected to one end of the arm 8 in a position facing the parabolic surface 6 and crossed by the aforementioned optical axis. The tubular body 11 has a terminal portion 12 for the entry of the light beam 6 closed in a fluid-tight manner by a plate or screen 13 permeable to light, and an opposite terminal portion 15, also closed in a fluid-tight manner by means of an annular disc 16 (Figures 2 and 3) housed in the end portion 15. The opening 18 (Figure 3) of the annular disc 16 is closed, again in a fluid-tight manner, by a flat support or reference plate 19, which in the particular example described carries a single photovoltaic cell 19a. The cell 19a conveniently has a quadrangular shape and a flat photovoltaic surface of incidence of the aforementioned light beam, the extension of which can be a few square millimeters for high concentrations of light and is in any case variable according to requirements. In any case, the ratio between the photovoltaic surface and the parabolic surface 6 is always less than one. Preferably, the flat photovoltaic surface extends orthogonally to the axis of the light beam in a position close to the focal point of the light beam itself and, conveniently, in a position such that the focal point lies on the photovoltaic surface of incidence or is placed aside. opposite the incident photovoltaic surface with respect to the parabolic body 5. The photovoltaic cell 19a is electrically connected to an electrical wiring comprising two cylindrical electrical contacts 21 protruding outside the tubular body 11 through the annular disk 16. The tubular body 11, the annular disk 16 together with the plate 19 with the photovoltaic cell 19a and the plate 13 form part of the device 10 and define a sealed chamber 22 (figure 2), which houses an electrically insulating and refrigerant liquid moved along a cooling circuit 23 , schematically illustrated, through an opening inlet 24 and an outlet opening 25 obtained through the portion 15.

The liquid used has a crystalline appearance and is a silicone liquid and, preferably, a polydimethyl silicone liquid. Conveniently, the liquid used is known by the commercial term “DOW CORNING® 561”. This liquid has a viscosity at 25 ° centigrade varying between 40 and 60 mm² / s, a thermal conductivity varying between 0.10 and 0.20 W | (mK) and a flash point greater than 300 ° C. The liquid also has a variable combustion temperature between 350 ° and 400 ° centigrade, a volume resistivity at 25 ° C equal to 1.0x1014 ohm.cm, a dissipation factor at 25 ° and 50 Hz variable between 0.00009 and 0.00015 and a refractive index at 25 ° varying between 1.35 and 1.45.

The liquid commercially known as “DOW CORNING® 561” has a high transfer efficiency especially due to the fact that it associates with a crystalline aspect and, therefore, with a high permeability to light, and a high thermal stability. At the same time, the polydimethylsilicone liquids and, in particular, the liquid "DOW CORNING® 561, have a resistance to exposure to sunlight that is not only high but substantially invariant over time, excellent convection capacities, are neither polluting nor toxic and therefore safe for the 'man and the environment if, for different reasons, they are dispersed in the external environment or inhaled. The above liquids are, above all, neither aggressive nor corrosive materials so they do not impose limitations in the choice of materials to be used for the construction of the sealed chamber in which they are housed. Not only that, but the aforementioned liquids do not require particular precautions in geometric terms and / or oversizing the details made with these materials.

In use, the light beam generated by the surface 6a directly affects the surface of the photovoltaic cell 19a, which, in response and in a known way, generates electrical energy fed through the electrical contacts 21 and heat transferred to the outside through the refrigerant circuit 23 and recovered in a known way.

In the variant illustrated in Figure 4, the tubular body 11 together with the cooling circuit 23, the disc 16 together with the plate 19 and the relative electrical circuit are arranged in a remote position with respect to the parabolic body 5, in the particular example described near the base 3 or, according to a variant not shown, in a position spaced from both the base 3 and the parabolic body 5 so as to be easily reachable by a person in charge of control and maintenance. In this configuration, the device 10 comprises a group 30 for transferring the light energy between the arm 8 and the tubular body 11.

The transfer unit 30 comprises a funnel-shaped body 31 for the entry of the light beam connected in a fixed position to one end of the arm 8 so as to be intersected by the optical axis. With reference to Figure 5, the funnel-shaped body 31 is closed on the part facing the parabolic body 5 in a fluid-tight manner by means of a screen 32 permeable to light and has an outlet collar 33 connected, again in a fluid-tight manner, to an end portion of a rigid or flexible pipe 34. In the example described, the pipe 34 has a constant section and includes a curved section and a straight section. The pipe 34 is indifferently made of plastic, metal or composite material and has a side wall impermeable to light and an internal reflecting surface, conveniently chromed.

According to a variant not shown, the pipe 34 has a plurality of rectilinear portions interspersed with curved portions.

An opposite end portion of the pipeline 34 is fluid-tight connected to the portion 12 via a further portion 35. The portion 35 constitutes an extension of the tubular body 11 beyond the screen 13 and is stably connected to the fluid-tight portion 12 to jointly define to the pipe 34 and to the body 31 an elongated chamber 38 filled with a light energy transfer liquid which, preferably, but not necessarily, is identical to the liquid passing through the chamber 22. In the particular example described, the two liquids are separated from each other by the screen 13. According to a variant, the device 10 has no screen 13 and, therefore, the same liquid fills the elongated chamber 38, the chamber 22 and the cooling circuit 23.

From the foregoing, it is evident that in group 1 described, since the light radiation incident on the photovoltaic cells is not of natural intensity, as in known solutions, but of high intensity due to the focus caused by the parabolic surface 6, the quantity of energy per unit of surface area produced by the photovoltaic cell 19a is extremely higher than that produced by the photovoltaic cells of traditional photovoltaic panels. In the specific case, it has been experimentally found that in group 1 described a photovoltaic surface of a few square millimeters produces the same energy produced by a traditional photovoltaic panel having a photovoltaic surface of over one square meter. Experimentally it was then also found that the above result can be obtained both in the case of the solution of figure 1, i.e. with a photovoltaic cell directly illuminated by the light beam, and in the case of figure 4 where the light radiation is moved to a remote position through the transfer unit 30. The constructive characteristics of the unit 30 allow, in fact, first of all, to transfer the light radiation in the substantial absence of losses since the pipe 34 and the bodies 31 and 35 are impermeable to light, but above all they allow to arbitrarily choose the path of shift. The foregoing is essentially a consequence of the use of the particular liquid described, which due to its chemical-physical characteristics has proved to be an excellent vehicle for the transfer of light waves. Specifically, the liquid used makes it possible to transfer an incoming light beam to any exit point following any path of advancement and in the substantial absence of leaks. In fact, according to the invention, the pipe can be freely shaped according to the route requirements being, on the practical side, a common pipe for liquids, and the liquid contained in it does not place limitations on the geometric choices and on the section / variation of section of the same pipe as it simply adapts to the space inside the pipe itself. The liquid used is then substantially insensitive to thermal variations, so that it can be used for connections of environments even at very different temperatures.

For the above reasons, the group 1 described allows for the same energy supplied, to drastically reduce the photovoltaic surface of incidence of light rays and, consequently, the overall dimensions compared to the existing solutions and makes it possible to install photovoltaic equipment in areas and in positions, in which traditional photovoltaic panels could not be positioned both for lack of space and for environmental impact problems. Not only that, but precisely due to the fact that for the same amount of energy supplied, the unit 1 described can be arranged in easily reachable positions, eliminating the known practical difficulties of installation and considerably facilitating the normal operations of control and routine maintenance.

The control and maintenance operations are further facilitated in the case in which the photovoltaic cell is arranged in a remote position with respect to the parabolic body 5, ie in the case of use of the liquid transfer device 30. In this condition, in fact, the photovoltaic cell can be arranged in any position by exploiting the flexibility of the pipe and / or the fact that curved sections can be interspersed with straight sections without any limitation to predetermined paths.

In addition to what has just been explained, it should be noted that reduced photovoltaic surfaces of incidence of light rays immediately translate into a drastic reduction in construction costs since the number of photovoltaic cells used is particularly reduced, already expensive in themselves due to the particular materials used for the their realization, and the costs of assembly or electrical connection of the photovoltaic cells between them.

From the foregoing it is clear that modifications and variations could be made to the group described without thereby departing from the protective scope defined by the claims. In particular, the photovoltaic cell device 10 could comprise more than one photovoltaic cell having the same or different shape and size from those described by way of example. In particular, the flat photovoltaic cell 16 could be replaced by curved photovoltaic cells, or be associated with curved photovoltaic cells suitable for capturing any reflected rays. In the latter case, the photovoltaic cells would partially or completely cover both the disc 16 and the internal side walls of the tubular body 12.

Claims (1)

CLAIMS 1. Photovoltaic cell generator unit comprising a support arm and a photovoltaic cell device carried by said support arm and comprising at least one photovoltaic surface of incidence of a light radiation, characterized in that it also comprises a parabolic reflecting body carried by said support arm and generating a light beam having its own optical axis and converging at a focal point, and by the fact that said photovoltaic cell device comprises input means for said light beam arranged in a position facing the said parabolic body and along said optical axis and a cooling circuit of said incident photovoltaic surface; the said cooling circuit using an electrically insulating and coolant liquid. 2. A unit according to Claim 1, characterized in that the said inlet means are supported by a second arm extending overhanging from a perimeter edge of the said parabolic body. 3.- Group according to claim 1 or 2, characterized by the fact that said photovoltaic incidence surface extends inside the said input means in a position adjacent to said focal point. 4. A unit according to claim 3, characterized in that said photovoltaic incidence surface extends at least partially orthogonally to said optical axis. 5.- Group according to claim 1 or 2, characterized by the fact that said photovoltaic surface of incidence extends inside said input and by the fact that said focal point lies on said photovoltaic surface of incidence. 6. A unit according to Claim 1 or 2, characterized in that said photovoltaic incidence surface extends in a remote position with respect to said input means; said photovoltaic cell device further comprising means for transferring light waves interposed between said input means and said photovoltaic incident surface; said transfer means comprising a light permeable transfer medium in liquid or gel form. 7. A group according to Claim 6, characterized in that the light permeable transfer medium is a silicone liquid. 8. A group according to Claim 6 or 7, characterized in that said light permeable transfer medium is a polydimethylsilicone liquid. 9.- Group according to one of Claims 7 or 8, characterized in that the said silicone liquid has a thermal conductivity of between 0.10 and 0.20 W | (mK). 10.- Group according to one of Claims 7 or 8, characterized in that said silicone liquid has a dissipation factor at 25 ° and 50 Hz which varies between 0.00009 and 0.00015. 11.- Group according to any one of claims 6 to 9, characterized in that said transfer means comprise a pipe closed, on the one hand, by said inlet means and, on the other, at least partially by said photovoltaic surface of incidence; said pipe housing said light transfer means. 11. Group according to Claim 10, characterized in that said pipe is flexible to follow an at least partially curved path. 12. A unit according to Claim 10 or 11, characterized in that said liquid light transfer medium and said electrically insulating and refrigerating liquid are separate from each other. 13. A unit according to Claim 10 or 11, characterized in that the said transfer means comprise a pipe that communicates hydraulically with the said cooling circuit and use a silicone or polydimethylsilicone liquid in common with the said cooling circuit.