Camouflage cover for photovoltaic panels or solar thermal panels

Abstract

Device for camouflaging and / or decorating photovoltaic panels or solar thermal panels comprising a transparent flat plate (1) made of plastic material and a perimetral frame (2) designed to be applied onto the side edges (C) of at least one photovoltaic panel or solar thermal panel (P). The flat plate (1) can be applied to the upper face of said at least one photovoltaic panel or solar thermal panel (P) by means of the perimetral frame (2) to provide protection against dust and atmospheric agents. On the flat plate (1) a camouflage and / or decoration visual graphic (10) is printed.

Description

[0001] "Camouflage cover for photovoltaic panels or solar thermal panels"

[0002] TEXT OF THE DESCRIPTION

[0003] Field of the Invention

[0004] The present invention relates generally to a device for camouflaging and / or decorating photovoltaic panels or solar thermal panels and concerns , more particularly, a device comprising a cover designed to be applied onto the upper face of at least one photovoltaic panel or solar thermal panel .

[0005] State of the Art

[0006] The increasing use of electrical or thermal energy from renewable sources and their spread across the national territory has led to an ever-greater evaluation of the environmental impact aspect for all types of renewable technologies .

[0007] In particular, for photovoltaic plants for electricity production and for solar plants for thermal energy (hot water ) production, there are di f ferent aspects to evaluate :

[0008] • Large plants and thus expanses of panels positioned on the ground which have a maj or visual impact both from great heights and from di f ferent observation points ,

[0009] • Residential plants in areas with landscape constraints : for example rural , agricultural areas , historic centers , coastal areas , etc .

[0010] • Industrial plants of companies , immersed in protected agricultural contexts or those designated as world heritage sites such as , for example , the Langhe , Roero , Monferrato , or in marine contexts , etc .

[0011] • Plants within the highway network that winds through often pristine landscapes .

[0012] This impact has prevented or limited the spread of photovoltaic plants in these areas , with serious repercussions on the speed of the ecological transition . Furthermore , since Italy is dotted with history, areas of historical and environmental interest and has a very particular conformation and morphology, it could lead to a failure to achieve the obj ectives imposed by the European community for energy independence from fossil fuels .

[0013] For this reason, many people have studied and continue to study solutions to reduce the aesthetic impact and camouflage photovoltaic panels or solar thermal panels without excessively limiting their performance . In this regard, the current state of the art is essentially encompassed in two types of products : • Printed films .

[0014] These are plastic films ( foils ) that are printed on rolls and subsequently applied with adhesives directly onto the exterior of the glass or outer plate of the photovoltaic panel or solar thermal panel . Such solutions present the following drawbacks :

[0015] The adhesives used to perfectly adhere the films to the glass , over time , being continuously subj ected to atmospheric agents and UV rays , tend to crystalli ze and peel ; for this reason, they cannot have long-term guarantees like those of existing photovoltaic panels or solar thermal panels ,

[0016] The types of textures and inks used heavily degrade the performance of photovoltaic panels with losses even greater than 50% ,

[0017] Di f ficulty in replacing the film both in the removal phase from the panel , and in the phase of removing the adhesive from the glass surface , and in the laying and perfect adhesion phase of the new film, having to guarantee secure anchoring over time in addition to the di f ficulties for any new installations o f the " covers" on existing photovoltaic and thermal panels ,

[0018] No protection against hail , as the film is thin .

[0019] • Digital printing directly onto the glass or outer plate o f the photovoltaic panel or solar thermal panel . Such solutions present the following drawbacks :

[0020] Digital printing directly onto glass is a recent technology and uses ceramic-based inks that are not transparent to visible light and therefore , also in this case , heavily degrade panel performance with losses even greater than 50% ,

[0021] Logistics become complicated and limit its use : the glass must be printed before assembly at the photovoltaic panel or solar thermal panel production plant , and the camouflage cannot be replaced over time because it is an integral part of the components forming the produced panel ,

[0022] The ink is not protected from UV rays and therefore fading of colors is inevitable , leading to loss of the camouflage function; furthermore , it is not subj ect to replacement except by changing the photovoltaic panel or solar thermal panel ,

[0023] No supplementary mechanical protection for the original panel against hail , UV rays , salt corrosion, etc .

[0024] There is therefore a need for a device for camouflaging and protecting photovoltaic panels or solar thermal panels that is practical , economical , simple and functional .

[0025] Summary of the Invention The purpose of the present invention is to overcome the aforementioned drawbacks and to provide a device for camouflaging and / or decorating photovoltaic panels or solar thermal panels that is easily applicable and removable , easily customi zable according to the speci fic needs of the customer directly on site , that minimi zes the loss of panel performance , that allows protecting photovoltaic panels or solar thermal panels from atmospheric agents such as hail , that is economical and, as far as possible , ecological .

[0026] According to the invention this purpose is achieved by means of a device for camouflaging and / or decorating photovoltaic panels or solar thermal panels comprising a transparent flat plate made of plastic material and a perimetral frame designed to be applied onto the side edges , i . e . , the frame , of at least one photovoltaic panel or solar thermal panel , wherein the flat plate can be applied to the upper face of the at least one photovoltaic panel or solar thermal panel by means of the perimetral frame to guarantee its mechanical anchoring, compensation for the di f ferent thermal expansion between panel and camouflage plate , and gradual elimination of any condensation protecting it from dust and atmospheric agents , wherein a visual graphic -visual graphic pattern- is printed on the plate .

[0027] According to a further advantageous characteristic of the invention the perimetral frame comprises fastening devices to the photovoltaic panel or solar thermal panel .

[0028] According to a further advantageous characteristic of the invention, the visual graphic is printed with a pattern of dots , so-called printing texture with a variable ratio between empty and full spaces , wherein the diameter of the dots is between 1 and 10 mm, the distance between the dots is between 2 and 20 mm, and the printed surface is between 20% and 80% of the total surface area of the plate . In this way it is possible to minimi ze the loss of ef ficiency of the photovoltaic panel or solar thermal panel while maintaining the obj ective of its camouflage in the surrounding environment .

[0029] In an embodiment of the device according to the invention, the visual graphic is printed in four- color process without black printing, the white curve is reduced by 60- 90% , and the printing resolution is between 250 and 850 dpi .

[0030] In an embodiment , the visual graphic is printed on the inner face of the plate , i . e . , the face in contact with the photovoltaic panel or solar thermal panel . Alternatively, the visual graphic is printed on the outer face of the plate .

[0031] In an embodiment , the graphic is made so as to camouflage the photovoltaic panel or solar thermal panel in the surrounding environment by representing one or more of : roof tiles , shingles , ivy, stones , gravel , slate , flagstones , vegetation or subj ects developed on re quest / custom! zed .

[0032] In an alternative embodiment of the device according to the invention, the graphic is obtained from an aerial photograph of the area surrounding the installation of the at least one photovoltaic panel or solar thermal panel .

[0033] In a further embodiment the graphic is an aesthetic enhancement decoration representing either a replica of a work of art , or a "design" decoration comprising textures and chromatic patterns replicating marbles , stones , wood .

[0034] In an embodiment , the graphic is aimed at commercial communication representing institutional advertising messages .

[0035] In a further embodiment , the graphic is obtained via printing with an ink made from micro-ground natural solid pigments of classes 7 and 8 .

[0036] In an embodiment , the device according to the invention is designed to be fixed onto photovoltaic panels or solar thermal panels provided for cladding building facades .

[0037] In an embodiment , the perimetral frame is configured to allow sliding of the plate that occurs due to dimensional variations caused by thermal expansion or contraction .

[0038] In a further embodiment , the perimetral frame of the device according to the invention comprises at least one device designed to allow the gradual exit of any condensation that may form between the glass of the photovoltaic panel or solar thermal panel and the plate .

[0039] In an embodiment , the plate comprises at least one covering film for the visual graphic . This film allows protecting the ink used for printing the graphic from atmospheric agents , especially dust and UV rays .

[0040] In an embodiment , the percentage reduction in ef ficiency of the photovoltaic panel or solar thermal panel on which the device according to the invention is installed is limited between : 28 %-33% for a graphic with red roof tiles , 25%-31 % for a graphic with green ivy, 24 %-30% for a graphic with stones and / or gravel , 26%-32 % for a graphic with flagstones , compared to the same photovoltaic panel or solar thermal panel without such a device .

[0041] The present invention also has as its obj ect a method for printing of a visual graphic on a plate of a device for camouflaging and / or decorating photovoltaic panels or solar thermal panels comprising the steps of :

[0042] - printing, by means of a digital drop-on-demand printhead, a pattern of dots having a diameter between 1 and 5 mm and a spacing between 2 and 10 mm; - drying the ink by means of an IR lamp, NIR lamp, hot air drying, infrared and optionally comprising a further step of drying the ink printed on the plate in a static oven .

[0043] Brief Description of the Drawings

[0044] The invention will now be described in detail with reference to the accompanying drawings , provided by way of non-limiting example only, in which :

[0045] Figure 1 is a schematic perspective and partially exploded view of a first embodiment of a device for camouflaging and / or decorating photovoltaic panels or solar thermal panels according to the invention,

[0046] Figure 2 is a front view of a crosssection of the first embodiment of the device according to the invention installed on a photovoltaic panel or solar thermal panel ,

[0047] Figure 3 is a schematic perspective and partially exploded view of a second embodiment of a device for camouflaging and / or decorating photovoltaic panels or solar thermal panels according to the invention, and

[0048] Figure 4 is a front view of a crosssection of the second embodiment of the device according to the invention installed on a photovoltaic panel or solar thermal panel .

[0049] Detailed Description

[0050] Hereinafter, the device for camouflaging and / or decorating according to the invention, also called " cover" , is described in detail . Referring initially to Figure 1 , reference numeral 1 indicates a flat rectangular transparent plate made of plastic material on which a visual graphic 10 is printed representing, by way of non-limiting example , a series of roof tiles . Reference numeral 2 indicates a rectangular perimetral frame comprising a vertical edge 3 and a horizontal edge 4 . Reference P indicates a generic photovoltaic panel or solar thermal panel comprising a side edges C and a protective glass V for the solar cells in the case of a photovoltaic panel or for the heat exchanger in the case of a solar thermal panel , not shown as they are generally known . The dimensions of the flat plate 1 and the perimetral frame 2 conform to those of the various photovoltaic panels or solar thermal panels on the market .

[0051] In Figure 2 , the device for camouflaging and / or decorating according to the invention installed on a photovoltaic panel or solar thermal panel P is shown .

[0052] The flat plate 1 is applied onto the upper face of the photovoltaic panel or solar thermal panel P, and is applied to it by means of the rectangular perimetral frame 2 so that the vertical edge 3 of the perimetral frame 2 is partially overlapped with the side edges C of the photovoltaic panel or solar thermal panel P, and the hori zontal edge 4 is partially overlapped with the upper face of the flat plate 1 . It should be noted that between the side edges C of the photovoltaic panel or solar thermal panel P and the perimetral edge of the flat plate 1 , an adequate space is provided to allow both the sliding of the plate 1 that may occur due to dimensional variations caused by thermal expansion or contraction and the gradual release of condensation, which occurs gradually precisely because the plate rests on the panel ' s glass and the frame is not sealed . The anchoring system has indeed been designed to allow a calibrated locking of the cover onto the panel P so as to allow the thermal expansion of the cover . The thermal expansion of the cover, which is made of plastic material , is in fact very di f ferent from that of the panel P .

[0053] The flat plate 1 applied above the photovoltaic panel or solar thermal panel P of fers two main advantages . Firstly, it protects the glass V of the panel P from dust and atmospheric agents such as rain and hail , prolonging its li fespan and maintaining its ef ficiency over time . Secondly, it allows camouflaging the panel P thanks to a customi zed visual graphic 10 that recalls the surrounding context , such as the roof of a house , aesthetically integrating the system into the environment where it is installed .

[0054] The device according to the invention can be applied to the photovoltaic panel or solar thermal panel P by pressure- fitting the perimetral frame 2 onto the side edges C, or, fastening devices to the panel can be provided, for example the same mechanical fastenings already used to fix the panels .

[0055] A variant of the invention, so-called " cover plus" , is shown in Figures 3 and 4 in which parts identical or similar to those previously described are indicated with the same reference numerals . Above the flat plate 1 , a pair of sel f-cleaning films 7 , 8 are applied to protect the visual graphic 10 both from atmospheric agents such as rain and sun, and from the sliding of the plate 1 against the hori zontal edge 4 of the perimetral frame 2 caused by thermal expansion or contraction . The films may consist , as a non-limiting example , of a multilayer film with special sel f-cleaning characteristics , UV resistance , with low thermal transmission and high visible light transmission .

[0056] According to an advantageous characteristic of the invention, the visual graphic 10 is printed with a pattern of dots , so-called printing texture with a variable ratio between empty and full spaces , wherein the diameter of the dots is between 1 and 10 mm and the distance between the dots is between 2 and 20 mm .

[0057] As mentioned previously, the visual graphic 10 is made so as to camouflage the installed photovoltaic panel or solar thermal panel P, for example , on the roof of a house and, in addition to the visual graphic 10 representing roof tiles visible in the Figures by way of example , it can represent shingles , ivy, stones , gravel , slate , vegetation or a combination thereof .

[0058] The visual graphic 10 is printed on the plate 1 by means of a digital process that allows for extreme customi zation; in addition to graphic proj ects on request , it is possible to of fer a maximum level of customi zation to camouflage with extreme precision relative to the context , habitat , structures , etc . , for example by taking photographs and recordings with a drone of the area of interest for generating files aimed at reproducing the parts / themes agreed with the user for the production of the camouflage cover . The idea of such a camouflage cover on photovoltaic panels or solar thermal panels is innovative and unique , as it associates an innovative technical solution with an inkj et digital technology with an innovative ink type and speci fic visual graphic 10 .

[0059] An alternative for the visual graphic 10 for the plate 1 is an aesthetic enhancement decoration that can represent a replica of a work of art , or a "design" decoration comprising textures and chromatic patterns replicating marbles , stones , wood .

[0060] A further alternative is a visual graphic, aimed at commercial communication, representing institutional advertising messages for companies interested in giving visibility to their brand .

[0061] The device according to the invention is designed to be fixed both to panels installed on house roofs , and to panels provided for cladding building facades , and to panels installed on the ground .

[0062] Thanks to the characteristics listed above of the base material , the ink and the type of printing, the performance of photovoltaic panels or solar thermal panels does not degrade much .

[0063] The percentage loss of performance relative to the original photovoltaic panel or solar thermal panel without a cover is limited between : 28 %-33% for a visual graphic with red roof tiles , 25%-31 % for a visual graphic with green ivy, 24 %-30% for a visual graphic with stones and / or gravel , 26%-32 % for a visual graphic with flagstones .

[0064] INK

[0065] Considering the final application of the device according to the invention, which aims to completely eliminate the environmental visual impact of photovoltaic plants , the decoration and therefore the ink is one of the fundamental elements for achieving the final results . For this reason, the applicant has experimented, developed and produced an eco-compatible water-based ink that has the characteristic of being transparent in the visible light range so as not to create a particular barrier to the photons / light that activates the PV cells , having high resistance to the UV ray spectrum . The ink is made with micro-ground natural solid pigments of classes 7 and 8 that allow penetration and anchoring into the substrate and high light resistance and do not contain dyes .

[0066] PRINTING TEXTURE

[0067] Since printing i s the fundamental characteristic of the proj ect , the visual graphic part also assumes extreme importance for achieving the final results . The obj ective of the cover is to obtain a camouflage ef fect when viewing the panel P from a distance greater than 5 meters while allowing most visible light to pass through . The applicant has conducted countless tests and related performance los s measurements and has therefore developed a special final printing texture with a variable ratio between empty and full spaces depending on the type of camouflage subj ect .

[0068] The characteristics of the special texture for all decorative subj ects are :

[0069] • Hole diameter l - 10mm

[0070] • Hole pitch 2 -20mm

[0071] • Printed surface 20-70%

[0072] • File resolution 100- 400 dpi

[0073] • Printing resolution 250- 850 dpi

[0074] TYPE OF PRINTING

[0075] One of the main characteristics of the proj ect is the printing versatility and the extreme possibility of customi zation .

[0076] For this reason, it was also necessary to adapt the type of digital printing, existing on the market , to the type of material and the type of ink . In fact , needing to have a print that is not only decorative with 100% coverage , but a print with well-defined empty / full spaces , it is necessary to have a high printing definition on the defined plastic material . The applicant therefore had to develop, with the ink formulation previously described, a well-defined ink deposit , with micrometric droplets deposited on the plastic surface, which is very slippery, so that the droplet remained circumscribed without smearing, and that it dried quickly to maintain its correct shape , to then have a subsequent color drying in an oven or with another drying process (NIR, infrared, etc . ) for the final drying . However, it is important to avoid the droplet drying too quickly, as this could cause the formation of a surface crust . This crust would prevent final deep drying, thus compromising UV resistance , mechanical resistance and adhesion over time .

[0077] This aspect characteri zes the method for printing for any material; excessive drying "burns" the parts of the color, pigments and binding substances for "gripping" to the material, nullifying the cohesion of the color with the substrate: the color "powders". The applicant conducted multiple tests with different printheads and drying methods and a special printhead and printing machine were selected; the main characteristics are reported below:

[0078] • Digital printhead with micrometric deposit,

[0079] • Micrometric deposit type - appearance extremely variable depending on color density / file type and material absorbency / receptivity ;

[0080] • Type IR or NIR lamp drying complemented by possible drying in a static oven or hot air drying, infrared.

[0081] Different types of plastic materials were examined :

[0082] • Extruded and cast material: to have a tolerance <+-12%

[0083] • Transmittance: >90% in the visible light range i.e., between 350-700 nanometers

[0084] • Thermal expansion: <0.09 mm / m°C

[0085] • Impact resistance : >50 KJ / m2

[0086] • Abrasion resistance >25 % Haze

[0087] • Continuous operating temperature: >70°C

[0088] • Construction material class: class B2

[0089] • Combustion behavior: class E

[0090] The applicant analyzed different types of plastic materials and the best compromise was achieved with the rigid plate plastic material. Priority was given to transmittance which is 92% in order to have a low reduction in the performance of the original photovoltaic panel or solar thermal panel P. Furthermore, this material, in addition to natural UV protection, has low smoke emission in case of fire and a yellowing guarantee of 30 years depending on climatic zones.

[0091] COVER PLUS VERSION

[0092] The applicant decided to design a cover called "plus" that can improve, compared to the base version, the following characteristics:

[0093] • Increased hail resistance; hail test with 55 mm diameter spheres passed positively at 11 points on the panel P

[0094] • Reduced heat transmission

[0095] • Self-cleaning surface

[0096] • Improved dust resistance

[0097] • Guarantee of ink durability over time by encapsulating it between the plastic cover material and film.

[0098] • Climatic chamber test at 85°C with 85% humidity :

[0099] After 500 h it lost 1% of efficiency compared to the new condition,

[0100] After 1000 h it lost 1.4% of efficiency compared to the new condition.

[0101] All this was achieved by minimizing the worsening of transmittance and therefore the final performance of the photovoltaic panel or solar thermal panel P compared to the base version.

[0102] To have a long-term adhesion guarantee, the multilayer film described previously was used. In this case, the digital printing is protected from any atmospheric, mechanical and corrosion events as it is encapsulated. Furthermore, the film also has a UV barrier that protects the ink and guarantees a longer lifespan.

[0103] • Base cover lifespan >10 years

[0104] • Cover plus lifespan >15-20 years Naturally, the construction details and the embodiments can be widely varied with respect to what has been described and illustrated, without thereby departing from the scope of the present invention as defined in the claims that follow .

Claims

CLAIMS1. Device for camouflaging and / or decorating photovoltaic panels or solar thermal panels, comprising a transparent flat plate (1) made of plastic material and a perimetral frame (2) designed to be applied onto the side edges (C) of at least one photovoltaic panel or solar thermal panel (P) , wherein said flat plate (1) can be applied to the upper face of said at least one photovoltaic panel or solar thermal panel (P) by means of said perimetral frame (2) to provide protection against dust and atmospheric agents, wherein a visual graphic (10) is printed on said flat plate ( 1 ) .

2. Device according to claim 1, characterized in that said visual graphic (10) is made with a pattern of dots, so-called printing texture with a variable ratio between empty and full spaces, wherein the diameter of the dots is between 1 and 10 mm, the distance between the dots is between 2 and 20 mm, and the printed surface is between 20% and 70% of the total surface of the flat plate ( 1 ) .

3. Device according to claim 1 or 2, characterized in that said visual graphic (10) is printed in four-color process, in that the white curve is reduced by 60-90%, and in that the printing resolution is between 250 and 850 dpi.

4. Device according to any one of claims 1-3, characterized in that said visual graphic (10) is made in such a way as to camouflage the photovoltaic panel or solar thermal panel (P) in the surrounding environment by representing one or more of: curved roof tiles, roof tiles, ivy, stones, gravel, flagstones, vegetation, and / or an aerial photograph of the area surrounding the installation of said at least one photovoltaic panel or solar thermal panel (P) .

5. Device according to any one of claims 1-3, characterized in that said visual graphic (10) is a decoration chosen from:- an aesthetic enhancement decoration representing a replica of a work of art, or a "design" decoration comprising textures and chromatic patterns replicating marble, stone, wood, a commercial communication representing institutional advertising messages.

6. Device according to any one of the preceding claims, characterized in that said visual graphic (10) is obtained by printing with an ink made with microground solid natural pigments of classes 7 and 8 in water-based formulation.

7. Device according to any one of the preceding claims, characterized in that it is designed to be fixed on photovoltaic panels or solar thermal panels provided for cladding building facades.

8. Device according to any one of the preceding claims, characterized in that said perimetral frame (2) is configured to allow the sliding of said flat plate (1) which occurs due to dimensional variations caused by thermal expansion or contraction, and in that the structure of the flat plate (1) allows the gradual discharge of any condensation between the glass (V) of the photovoltaic panel or solar thermal panel (P) and said flat plate (1) .

9. Device according to any one of the preceding claims, characterized in that said flat plate (1) comprises at least one multilayer film (7,8) covering said visual graphic (10) .

10. Device according to any one of the preceding claims, characterized in that the percentage of reduction in the efficiency of the photovoltaic panel or solar thermal panel (P) on which it is installed islimited to: 28%-33% for a visual graphic (10) with a red tile, 25%-31% for a visual graphic (10) with green ivy, 24%-30% for a visual graphic (10) with stones and / or gravel, 26%-32% for a visual graphic (10) with flagstones compared to the same photovoltaic panel or solar thermal panel (P) without said device.

11. Method for printing of a visual graphic (10) on a flat plate (1) of a device according to any one of the preceding claims comprising the steps of: - printing a dot pattern with a diameter between1 and 10 mm and a spacing between 2 and 20 mm using a digital printhead depositing micrometric drops of ink;- drying the ink by means of an IR lamp, NIR lamp, hot air drying, infrared or other systems.

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