WO2011004411A2

WO2011004411A2 - Automatic cleaning system for solar panel surfaces

Info

Publication number: WO2011004411A2
Application number: PCT/IT2010/000283
Authority: WO
Inventors: Annibale Magri
Original assignee: Folmag S.R.L.
Priority date: 2009-07-07
Filing date: 2010-06-25
Publication date: 2011-01-13
Also published as: WO2011004411A3; ITBS20090130A1; IT1396499B1; EP2452135A2

Abstract

The invention relates to an automatic cleaning system for the surface of solar panels, in particular photovoltaic and hybrid solar panels. It comprises at least one tubular bar (12) that has a plurality of nozzles and is movable parallel to itself (13, 14) with outward and return strokes over the surface of solar panels (10) to be cleaned. Said tubular bar (12) is connected both to a source of washing water and to a source of pressurised air and managed so as to dispense, alternately, through the plurality of nozzles, jets of washing water during an outward stroke and jets of pressurised air during a subsequent return stroke over the surface of the panels.

Description

AUTOMATIC CLEANING SYSTEM FORSOLARPANEL SURFACES

Background of the invention.

The present invention relates in general to the sector of solar panels and refers in particular to a system for automatically cleaning the surface of such single or adjacent solar panels, especially photovoltaic and hybrid solar panels.

Prior art

Solar panels have been designed and structured to exploit solar energy and transform solar energy into energy that is useful for the activities of man.

They are usually classified as thermal solar panels that are intended to heat a fluid, photovoltaic solar panels that are intended to produce electric energy and hybrid solar panels intended for producing thermal energy and electric power at the same time.

Precisely because they are intended to collect solar radiation, such panels have to be exposed to the open air in an elevated position, on roofs or on the ground and be tilted as most appropriate towards the sun.

But located thus, they are also exposed to atmospheric agents. In order to be able to receive solar radiation fully, the surface of the solar panels, especially when they are photovoltaic and hybrid solar panels, is transparent, typically made of glass or the like, and has to be kept as clean as possible. It is, however, clear that in view of the exposure the surfaces of the solar panels are subject to deposits of dust and of substances that tend to make the surfaces opaque, thus limiting the absorption of solar radiation and the efficiency of the photovoltaic modules.

In order to overcome this drawback, washing systems have been adopted that simply use jets of pressurised water directed at the surface of the solar panels. The effectiveness thereof, however, appears to be slight and any way limited inasmuch as the water remains on the surface of the panels, and as it dries through the effect of evaporation it may leave calcareous deposits and/or impurities that still tend to make the surface opaque.

Object and summary of the invention.

The object of the present invention is to resolve effectively the problem of cleaning the surfaces of solar panels, in particular of photovoltaic and hybrid solar panels, not only through washing but also through forced drying thereof so that no deposits or substances remain that may limit the absorption of solar radiation.

Accordingly, the present invention proposes a cleaning system that essentially comprises at least one bar of nozzles that is oriented transversely and is movable parallel to itself with outward and return strokes over the surface of adjacent solar panels that is connected both to a source of washing water and to a source of pressurised air and is managed so as to dispense alternately jets of washing water during one stroke thereof and jets of pressurised air during a subsequent stroke over the surface of the panels.

In this manner the surface of the panels is first washed efficiently with jets of water and successively force-dried so as to remove immediately the coating and the drops of water from the surface so that no deposits or undesired marks remain thereupon.

Short description of the drawings.

The attached drawings show by way of non-limiting example an embodiment of the system according to the invention that will also be disclosed in greater detail subsequently. In said drawings: figure 1 shows schematically the system applied to a plurality of solar panels and figure 2 shows a plan view thereof.

Detailed description of the invention.

As shown, the system according to the invention is associable with a plurality of adjacent solar panels 10, in particular photovoltaic panels, that can be installed in any traditional manner. The system comprises supporting means 11 to be connected to a structure linked to the solar panels 10 and, on said structure, at least one horizontal tubular bar 12, arranged above and oriented transversely to the panels and carrying a series of nozzles. The tubular bar 12 with nozzles may be of the modular type and be composable in length in function of the width of the set of panels to be washed and the nozzles supported thereby can be fixed and be of the self-cleaning type, nevertheless oriented towards the surface of the panels 10.

The bar 12 with nozzles is movable parallel to itself over the panels 10 with an outward and a return stroke, according to the arrows in Fig.2, respectively from bottom to top and vice versa when the panels 10 have a tilted arrangement.

For this purpose, the bar 12 is connected to a movement device that may consist of a least one pair of parallel belts 13 or the like driven on respective transmissions or pulleys 14, two of which are coaxial and fastened to a control shaft 15 rotated by a reduction gear connected thereto, with no need for synchronisation. Also the control shaft 15 can be modular and be composable in length according to the width of the panels to be washed.

The tubular bar 12 carrying the nozzles is connected both to a washing water source and to a pressurised air source by conduits according to the arrows A and Ar, respectively. The water source - which is not shown - may consist of an autoclave or of a dedicated pumping system and at least for winter temperature problems it will be sheltered, in a loft, or will be thermally insulated. The source of pressurised air may consist of a compressor 16 that can be located anywhere according to necessity, also on a roof.

The system can be managed by a suitable programming unit in such a manner that the bar 12 with nozzles is connected alternately to the water source during at least one outward stroke of the bar 12 and to the pressurised air source during the return stroke of the bar 12. Thus, for example, with a tilted arrangement of the panels 11, the panels 11 are washed with jets of pressurised water when the bar 12 with nozzles moves from bottom to top and are then dried by jets of pressurised air when the bar 12 with nozzles performs the stroke from top to bottom so as to evacuate each coating and drop of water from the surface of the panels, leaving the surface perfectly clean.

In practice, the pressurised water and pressurised air are dispensed alternately from the same single series of nozzles, with the advantage of simplicity in the creation of the system and of emptying of the washing bar by the air.

For example, the system disclosed above could start operation and perform the washing and drying cycle at first light each day under the control of a sensor or of information coming from the solar panels, such as to make the surfaces of the latter completely clean for subsequently receiving the daily solar radiation.

It should lastly be noted that each washing and drying cycle, if required, could be repeated several times and that the water and air could be dispensed to the surfaces of the panels to be cleaned also through different bars provided that they are paired and are movable together to perform a washing and a forced drying action alternately.

Claims

1. Automatic cleaning system for the surface of single or adjacent solar panels, in particular photovoltaic and hybrid solar panels, characterised in that it comprises at least one tubular bar (12) that has a plurality of nozzles and is movable parallel to itself (13, 14) with outward and return strokes over the surface of solar panels (10) to be cleaned, and in that said tubular bar (12) is connected both to a source of washing water and to a source of pressurised air and managed so as to dispense alternately, through the plurality of nozzles, jets of washing water during an outward stroke thereof and jets of pressurised air during a subsequent return stroke over the surface of the panels.

2. System according to claim 1, characterised in that the tubular bar (12) is oriented transversely to the panels to be cleaned and is movable according to the length of the panels, and the nozzles for the alternating dispensing of jets of water and of jets of air are distributed along said bar and face the surface of said panels.

3. System according to claim 1 or 2, characterised in that said tubular bar (12) is connected to a traversing device associated with supporting means carried by supporting elements (11) fixed to a structure linked to said panels, said traversing device comprising at least one pair of parallel straps (13), or the like, driven on respective transmissions or pulleys (14) two of which are coaxial and mounted on a control shaft (15) rotated by a reduction gear connected thereto.

4. System according to any preceding claim, characterised in that the tubular bar carrying the plurality of nozzles is composable in length by means of respective modular elements.

5. System according to any preceding claim, characterised in that the control shaft of the traversing device of the tubular bar carrying the plurality of nozzles is composable in length by means of respective modular elements.

6. System according to any preceding claim, characterised in that the source of washing water consists of an autoclave or of a pumping unit, and the source of pressurised air consists of a compressor.

7. Method for cleaning the surface of solar panels, in particular photovoltaic and hybrid solar panels, characterised by a first step of washing the surface of said panels with jets of pressurised water and a second step of drying the surface with jets of pressurised air.

8. Method according to claim 7, characterised in that the jets of washing water and the jets of pressurised air are dispensed alternately through the same plurality of nozzles carried by a tubular bar that is movable over the surface of the panels to be cleaned. Method according to claims 7 and 8, characterised in that the jets of washing water are dispensed during a stroke of the bar carrying the nozzles and the jets of drying air are dispensed during a subsequent stroke of the bar carrying the nozzles over the panels to be cleaned, said bar being connected alternately to a source of washing water and to a source of pressurised air.