WO2012063193A2

WO2012063193A2 - Solar collector

Info

Publication number: WO2012063193A2
Application number: PCT/IB2011/054969
Authority: WO
Inventors: Claudio Zenere; Michele Bidese
Original assignee: Koncentra Group S.R.L.
Priority date: 2010-11-09
Filing date: 2011-11-08
Publication date: 2012-05-18
Also published as: IT1402698B1; WO2012063193A3; ITVI20100296A1

Abstract

A solar collector having a housing body (2) of photovoltaic cells (3) and in which a self-bearing meshed structure (6) is present, comprising: a plurality of joints (7) aligned in rows (8) parallels to each other; a plurality of linear elements (9) each one connected to two joints (7). Each of the joints (7) consists of a substantially tubular body (5) opened at both ends, at one end to house one or more of said photovoltaic cells (3) and at the other end to allow the light beams to reach said photovoltaic cells (3).

Description

SOLAR COLLECTOR

Field of the invention

The present invention generally relates to the technical field of the solar panels for photovoltaic use and particularly concerns a photovoltaic collector.

More in detail, the present invention concerns the structure of a photovoltaic collector.

Background of the invention

It is known that one of the fields in which more investments are made for the research of new technologies is the field of the new energetic sources with particular reference to the renewable energetic sources.

One of these last ones is the sun. Elements, called photovoltaic cells, are in fact known, which transform the light beams which come into collision with them into electric energy. On the base of these elements photovoltaic panels or collectors are particularly diffused which are typically movable to be always placed in front of the sun. They comprise an assembly of photovoltaic cells associated in a single collector which sum up their work of traducing the light beams which collide with them into storable electric energy or into directly usable electric power.

In this sense it is evident that research pushes to find technologies and methods which allow to increase as much as possible the electric energy produced by a single collector, trying, at the same time, to reduce the manufacturing and maintenance costs thereof.

In other words one of the points on which research is working is the reduction of the relation between the produced kilowatts and the cost for producing them, that is of the cost per kilowatt of the photovoltaic collectors.

In some cases they have worked and are working in increasing the yield of the single photovoltaic cells. Nevertheless, although the technique continuously advances, the yield of the known cells remains however low.

In other cases the photovoltaic collector has been provided with typically truncated cone shaped hollow bodies which, provided with inner surfaced structured for this purpose, convey as much as possible the light beams towards the cells, exactly like a funnel. For this purpose, on the head of the truncated cone shake body, where the light beams penetrate, a lens is typically present to focus them towards the photovoltaic cell. Another way to reach the result to decrease the cost per kilowatt is to increase the sizes of the photovoltaic collectors. They have in fact thought that a part of the costs of the collector are fix, therefore the increase of the sizes, which leads to an increased of the produced kilowatts, may reduce the cost per kilowatt. However the increase of the dimensions involves and increase of the manufacturing costs of the structure and of the means to move it. The photovoltaic cells, as well as the electronic part and the heat sinks which accompany them, have in fact a weight which increases with the number of the cells, that is with the increase of the dimensions of the photovoltaic collector.

A consequence is the need to use a supporting structure which can bear the weight increase. Such a structure has a typically important weight, so as to oblige to use suitable, and therefore particularly expensive, moving means of the collector.

Summary of the invention

The object of the present invention is to at least partly overcome the above drawbacks, by providing a photovoltaic collector which has a lower cost per kilowatt than the known equivalent collectors.

Within this general object, a particular object is to manufacture a photovoltaic collector which has a housing body which structurally has a lower weight than the known equivalent collectors although it may have particularly big sizes.

Consequently, an object of the present invention is to manufacture a photovoltaic collector the housing body of which has a structure suitable for the manufacture of big size although allowing to use moving means thereof with reduced power, and therefore costs in respect to the known equivalent collectors.

Another object of the present invention is to manufacture a photovoltaic collector in which the weight of the heat sinks of the employed photovoltaic cells is lower than the weight of the known equivalent collectors above all in the case of big size photovoltaic collectors.

The above objects, as well as others that will appear clearer hereinafter, are fulfilled by a photovoltaic collector according to one or more of the following claims which are integrant part of the present patent.

In particular, the photovoltaic collector may comprise a housing body of one ore more photovoltaic cells and a self-bearing meshed structure may be present within it.

This last one may on its turn comprise a plurality of joints aligned in rows parallel to each other and linked to each other by a plurality of linear elements.

What can be observed is that the structural seal of the photovoltaic collector of the invention would be ensured by a meshed structure which, speaking from a mechanical point of view, allows to optimize the control of the weights of the collector. In other words, a meshed structure is a structure which allows to control in the best way also big size photovoltaic collectors with a consequent spare in the manufacturing costs above all concerning the moving means.

In particular, the joints may be manufactured in a material with a low specific weight and comparatively low structural seal, which is committed to the linear elements.

According to an aspect of the invention, the joints consist of substantially tubular hollow bodies which develop along a transversal axis to the plane formed by the meshed structure. Moreover they may be provided along their perimeter with first tubular elements which develop along parallel axis to the plane formed by the meshed structure and which are designed to come into collision with the linear elements to manufacture the structure.

Typically these tubular hollow bodies may consist of truncated cone shaped bodies usually employed to convey the light beams towards the photovoltaic cells to increase the efficiency of the collector. For this purpose lenses suitable to focus the beams towards the photovoltaic cells may be present.

In other words, the joints may be manufactured by means of elements, the conveyers, which are already present in a photovoltaic collector reducing the weight of the collector and the manufacturing costs. The yield of the collector is improve by the conveyers.

All this therefore allows to reduce the cost per kilowatt of the so manufactured photovoltaic collector.

According to another aspect of the invention, among the linear elements a plurality of first elements may be placed substantially parallel to each other and each one susceptible to come into contact with respective first tubular elements belonging to joints placed on contiguous rows.

In other words, the meshed structure may be replaced by the joints and by the first linear elements which connect the joints. The linear elements may generally consist of rods or metallic bars.

Brief description of the drawings

Further features and advantages of the invention will become more apparent from the detailed description of a preferred, non exclusive embodiment of a photovoltaic collector according to the invention presented by way of illustrating and non-limiting examples in connection with the accompanying drawings in which:

FIG. 1 represents a photovoltaic collector according to the invention partially in transparency;

FIGS. 2 and 3 represent details of the photovoltaic collector of FIG. 1 in axonometric view;

FIG. 4 represents another detail of the photovoltaic collector of FIG. 1 in exploded section;

FIGS. 5 and 6 represent further details of the photovoltaic collector of FIG. 1 partially in section.

Detailed description of some preferred embodiments of the invention

With reference to the above figures, and particularly to fig. 1, a photovoltaic collector 1 having a housing body 2 of one or more photovoltaic cells 3 is described.

The housing body 2 also houses the part concerning the dissipation of the heat developed on the cells 3, at least a part of the protection electric circuitry and, possibly, a part of the electric circuitry of rectification and stabilization of the current generated by the cells 3.

According to what said above, the housing body 2 also house elements which contribute to improve the yield of the collector 1, as for instance conveying elements 4of the light beams towards the photovoltaic cells 3.

Typically, as visible in fig. 2, they consist of hollow tubular bodies 5 generally with a truncated cone shape open at the two ends. On one side they house one or more photovoltaic cells 3 on the other side the opening allows the passage of the light beams to the cells 3. For this purpose, the above mentioned opening is typically closed by means of a lens which focuses the beams towards the photovoltaic cells 3. Advantageously, moreover, the inner surface of the conveying elements 4 is typically manufactured with material which reflects the electromagnetic radiations to facilitate the conveying of the light beams. As the housing body 2 must be able to bear the weight of the photovoltaic cells 3, of the heat sinks and of the associated electric circuitry, according to an aspect of the invention it also houses a self bearing meshed structure 6.

This last one comprises, as visible in the detail of fig. 3, a plurality of joints 7 aligned according to rows 8 parallel to each other, and a plurality of linear elements 9 each one anchored to at least one pair of joints 7.

As observable, the meshed structure 6 may be manufactured in any material provided it can mechanically support the above mentioned components of the photovoltaic collector 1. In this sense particularly light materials may be employed so reducing the total weight of the collector 1. Consequently also the moving means of the collector 1 of the invention may have lower power and costs so reducing the cost per kilowatt of the collector 1 above all in case of big sizes.

As said above, the joints 7 are typically made in aluminium, whereas the linear elements 9 may be manufactured in iron or steel to structurally support the weight of the photovoltaic collector 1.

As the meshed structure 6 is in contact with the different parts composing the collector 1, the manufacturing thereof in thermally conducing material, as aluminium, advantageously increases the thermal dissipation and, with it, the yield in conversion of the photovoltaic cells 3. This further allows to reduce number and size of the employed sinks, so reducing the weight the meshed structure 6 has to support. The meshed structure may therefore be designed for smaller loads and this allows not only a direct saving in manufacturing costs, but also an indirect saving, as also the weight of the structure 6 is reduced. The total weight of the collector 1 is therefore even more optimized leading to a further saving on the moving means, that is to a further improvement of the already mentioned cost per kilowatt.

It has been said before that the photovoltaic collector 1 according to the invention comprises, at least in the described embodiment, conveying elements 4 which consist of substantially tubular hollow bodies 5, even if with truncated cone shape. As observable in the figures, they develop according to an axis transversal to the plane formed by the meshed structure 6. The convenience of using them to constitute the above mentioned joints is therefore evident, with an obvious simplification in the manufacturing of the meshed structure 6. In this sense, they are provided, along their perimeter, of first tubular elements 10 which develop along axis which are parallel to the plane formed by the meshed structure 6 and which constitute the connection between the joints 7 and the linear elements 9.

In this case, one or more of the linear elements 9 are susceptible to come into contact with respective first tubular elements 10 belonging to joints 7 disposed on contiguous rows 8.

Advantageously, therefore, elements are used which are already present in the photovoltaic collector 1, that is the conveyers of light beams, to manufacture the meshed structure 6 which has to support the weight thereof as well as the mechanical seal of the collector 1. This not only simplifies the manufacturing step, but also reduces the components number and the weight of the collector 1, with an obvious cost sparing and improvement of the cost per kilowatt of the photovoltaic collector 1 according to the invention with respect to the prior art equivalent collectors, especially if of big size.

Advantageously again, the first tubular elements 10, as observable also in the detail of fig. 4, are arranged in parallel pairs on opposite sides of a respective hollow tubular body 5. The first tubular elements 10 placed on the same side as the tubular bodies 5 aligned according to the same row 8 are crossed by the same linear element 9 which connects them. The linear element 9 also connects the first tubular elements 10 of the hollow tubular bodies 5 placed according to the immediately contiguous row 8. In other words, the same linear element 9 connects to each other hollow tubular body 5 of two contiguous rows. The assembly of the linear elements 9 is therefore sufficient to form, together with the joints 7, the meshed structure 6. In particular, the conveying elements 4, which make the joints 7, are disposed as a honeycomb.

However, according to another embodiment which is not represented here, the meshed structure may also comprise additional linear elements disposed substantially parallel to each other, orthogonal to the till here described linear elements, and each one susceptible to come into contact with respective first tubular elements belonging to joints disposed on contiguous rows. Essentially, whereas when only the linear elements described before the meshed structure is made by a series of parallel linear elements joined in pairs by the tubular bodies of a row, when the additional linear elements are also resent, the meshed structure is made by a grid of linear elements on whose crossings the tubular bodes are disposed. According to another aspect of the invention, the photovoltaic collector 1 also comprises, as observable in the details of figs. 5 and 6, second tubular elements 15 interposed between the linear elements 9 and the first tubular elements 10. As already said, in fact, the meshed structure 6, being in contact with the different parts composing the photovoltaic collector 1, may also work as a heat sink. In this case, if the linear elements 9 and the joints 7 are made in different materials, they may have thermal expansion coefficient with such a difference to compromise the mechanical seal of the single parts. The connection between the parts, therefore, and particularly between the linear elements 9 and the joints 7, is left more elastic. In other words, the inner diameter of the tubular elements 10, 15 is greater than the diameter of the linear elements 9 which come into contact with them. As the meshed structure 6, when cold, may be too movable, the second tubular elements 15 work as a hacker for the linear elements 9. However, also between the second tubular elements 15 and the first tubular elements 10 a thermal expansion difference may exist, so reproducing the above lamented problem. For this reason the second tubular elements 15 are steadily anchored to the first tubular elements 10.

More in detail, the joints 7 are preferably, but not necessarily, manufactured in aluminium which, as known, has a high thermal expansion coefficient. This material is particularly indicated because it is an excellent thermal conducer, it is particularly light and it is easy to work. In other words, it allows low production costs.

However, as the meshed structure 6 has to support remarkable loads, the linear elements 9 are generally manufactured with less malleable and flexible materials, such as, for example, steel. Steel has a definitely lower thermal expansion coefficient than aluminium, that is why, with heat, excessive relative movements develop. The use of the second tubular elements 15 allows to overcome this drawback. It is in fact sufficient to manufacture these last ones in the same material as the linear elements 9, or with a material having a similar thermal expansion coefficient, to avoid relative movements between linear elements 9 and second tubular elements 15.

The problem of the relative movements between the second tubular elements 15 and the first tubular elements 10 is solved by means of suitable reciprocal anchoring means. For example, as observable in the figures, the first tubular elements 10 may have, in the median portion, grooves 20 susceptible to receive fitting peg shake projections 21 present in the corresponding median portion of the second tubular elements 15.

The above disclosure clearly shows that the photovoltaic collector according to the invention overcomes the drawbacks of the prior art technique, having a lower cost per kilowatt than the known equivalent collectors.

In particular, the described photovoltaic collector is provided with a housing body which has structurally a lower weight than the known equivalent collectors even if it may have particularly big sizes.

In other words, the photovoltaic collector according to the invention has a structure suitable to the manufacturing of big size collectors although allowing to employ moving means thereof with reduced power, and therefore costs, with respect to the prior art equivalent collectors.

On closer inspection, the photovoltaic collector according to the invention has a particularly lightened weight and a structure with respect to the prior art equivalent collectors also because it employs heat sinks for the heat generated by the photovoltaic cells which have smaller size than the prior art equivalent collectors.

The photovoltaic collector of the invention is susceptible of a number of changes and variants, all within the inventive concept disclosed in the appended claims. All the details thereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.

While the photovoltaic collector of the invention has been described with particular reference to the accompanying figures, the numerals referred to in the disclosure and claims are only used for the sake of a better intelligibility of the invention and shall not be intended to limit the claimed scope in any manner.

Claims

C L A I M S

1 . A photovoltaic collector having a housing body (2) of one or more photovoltaic cells (3) and in which it have a self-bearing meshed structure (6) including:

a plurality of joints (7) aligned in rows (8) parallel to each other; - a plurality of linear elements (9) each anchored to at least two joints (7), characterized in that each of said joint (7) is made by a tubular body (5) opened at both ends, at one end to house one or more of said photovoltaic cells (3) and at the other end to allow the radiations to reach said photovoltaic cells (3).

2. Photovoltaic collector as claimed in claim 1, characterized in that said substantially tubular body (5) develops along an axis transversal to the plane defined by said meshed structure (6) and is provided, along its perimeter, by first tubular elements (10) that develop along axis parallel to the plane identified by said meshed structure (6).

3. Photovoltaic collector as claimed in claim 2, characterized in that said linear elements (9) are arranged essentially parallel to each other and each one is susceptible to come into contact with respective of said first tubular elements (10) belonging to joints (7) arranged in contiguous rows.

4. Photovoltaic collector as claimed in claim 2 or 3, characterized in that said tubular body (5) has substantially a truncated cone shape.

5. Photovoltaic collector as claimed in any of the preceding claims, characterized in that said tubular body (5) has the inner surface which reflects electromagnetic radiations to facilitate the conveyance of said light beams towards said photovoltaic cells (3).

6. Photovoltaic collector as claimed in any of the preceding claims, wherein that said first tubular elements (10) are arranged in parallel pairs on opposite sides of a respective tubular body (5).

7. Photovoltaic collector as claimed in any of the preceding claims, comprising second tubular elements (15) interposed between said linear elements (9) and said first tubular elements (10) to compensate possible thermal expansion differences between said linear elements (9) and said first tubular elements (10).

8. Photovoltaic collector as claimed in claim 9, characterized in that said second tubular elements (15) comprise anchoring means to said first tubular elements