EP4115044B1

EP4115044B1 - A system for shielding a building from sun rays

Info

Publication number: EP4115044B1
Application number: EP21711027.9A
Authority: EP
Inventors: Luca PAPAIZ; Alessandro Pellini
Original assignee: Pellini SpA
Current assignee: Pellini SpA
Priority date: 2020-03-03
Filing date: 2021-02-16
Publication date: 2024-04-03
Anticipated expiration: 2041-02-16
Also published as: IL295021B1; IT202000004483A1; CN115210443A; IL295021A; WO2021176288A1; EP4115044A1; IL295021B2

Description

Technical field

The present invention relates to a system for shielding sun rays, having properties of reflecting sun rays in the near infrared, in particular a system for shielding sun rays comprising a sun ray protection device, according to the preamble of claim 1.
Such system for shielding sun rays can in particular be applied, for instance, for shielding a building interior.

Background

It is known in the prior art using a system for shielding sun rays that can be applied to the facade of a building.
In particular, in order to limit the temperature increase in the interiors of a building, the known art provides a system for shielding sun rays which is arranged in the outermost part of the facade to shield it.
The known shielding system comprises a glass engaged to the facade of the building for instance by means of a support frame.
The shielding must be directed in particular to sun rays, which, as known, consist of luminous rays, i.e. rays in the visible wavelengths and rays in the near infrared and ultraviolet rays. In particular, sun rays in the near infrared means waves emitted by the sun with a wavelength in the range comprised between 780nm-2500nm and they do not contribute to lighting but they convey heat.
Traditionally, the glass used in the known systems is treated by a process known as PVD ("Physical Vapour Deposition") so as to obtain the characteristic of reflecting the component in the near infrared of sun rays. Such treatment allows to mitigate the sun power entering the facade of the building and thus reduce the temperature of the rooms defined by it.
Document US 2013163062 A1 discloses a smart window, with partially shading layers which can be aligned or overlaid to modulate the passage of the light. In one embodiment, the material at the basis of the modulation is a dielectric coating, that is transparent to the visible light but reflecting the infrared, applied on a transparent support. This allows to limit overheating.

Problem of the prior art

Disadvantageously, the PVD coating of the glass behaves as an interferential filter or dichroic filter, resulting in a physiological and significant chromatic aberration.
Such chromatic aberration generates, for users in the building, a sight aberration from inside towards outside, changing the colour of the surrounding environment as well as the colour of natural light. Consequently, serious consequences on the circadian rhythm of people living in the building may occur, as it strictly depends on the colour of natural light.
Still disadvantageously, the PVD coating of the glass implies an unesthetic appearance of the building when seen from outside. In fact, when a person outside the building observes the facade thereof, one can see inside through the glass being submitted to the negative effects of chromatic aberration. In addition, the building interiors are lighted by a natural light which has in turn been biased by the glass. It derives a distortion of the appearance of the building facade.
Furthermore the PVD coating of the glass is rather expensive thus reducing the applicability of the prior art system for shielding sun rays.
On the other hand, the transparent dielectric coating of US 2013163062 A1 does not at all shade the visible light, as it is instead desirable for instance during the summer.

Summary of the invention

Within this context, the technical task underlying the present invention is to provide a system for shielding sun rays which overcomes the drawbacks of the prior art.
In particular, it is the object of the present invention to propose a system for shielding sun rays which does not act as an interferential filter when it is applied to a building facade. In other words, it is the object of the present invention to envisage a system for shielding sun rays that does not produce a chromatic aberration.
It is also an object filtering infrared rays in an alternative way with respect to US 2013163062 A1 , allowing to shade the visible light during the summer.
The defined technical task and the specified objects are substantially achieved by a system for shielding sun rays comprising the technical characteristics set forth in one or more of the appended claims.

Advantages of the invention

Thanks to an embodiment of the invention it is possible to maintain the tone and colour of natural light as seen through the glass and, at the same time, maintain the appearance of the building onto which the system for shielding sun rays is applied.
Thanks to the preferred embodiment of the invention it is also possible to prevent that sun rays incident on the PVD coating-free glass generate an excessive increase of temperature in the building interiors.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will become more apparent from the indicative and thus non-limiting description of a preferred, but non-exclusive, embodiment of a system for shielding sun rays, as shown in the accompanying drawings, wherein:

Figure 1 is a section schematic representation of the system for shielding sun rays according to the present invention;
Figure 2 is a section schematic representation of an alternative embodiment of the shielding system of Figure 1;
Figure 3 is a section schematic representation of a further alternative embodiment of the shielding system of Figure 1;
Figure 4 shows a diagram, obtained with experimental tests carried out by the Applicant, of the reflection spectrum of the system for shielding sun rays of Figure 1.

DETAILED DESCRIPTION

Referring in particular to the enclosed figures, number 1 denotes a system for shielding sun rays.
Such system for shielding sun rays 1 can for instance be applied to shield a building facade or to shield a room facing the building facade.
Preferably, the shielding system 1 can be applied to a window 6 of the building to protect and shield from sun rays an interior of such building wherein at least a part of the interior is delimited by the window 6.
The shielding system 1 comprises at least one first glass 2.
The shielding system 1 comprises at least a second PVD coating-free glass 3. In other words, such second glass 3 is a glass transparent to sun rays.
In particular, such second glass 3 does not have properties of reflecting rays in the near infrared. As the second glass 3 is free from PVD coating, the chromatic aberration phenomenon is avoided.
According to an aspect, the first 2 and the second glass 3 may be a glass sheet, preferably plane, single, double or triple, with or without chambers in between the various sheets.
According to an aspect the first 2 and second 3 glasses are parallel to each other.
It is worth noting that the linear dimensions as well as the thickness of the sheet of glass 2, 3 are determined by the specific use.
Such second glass 3 is associated to the first glass 2 by a support frame 5 to form a gap 51.
In particular, such gap 51 is delimited by the first glass 2, the second glass 3 and the support frame 5.
It is known in the art associating the first glass 2 and the second glass 3 in the frame 5 and therefore it will no further be disclosed.
In the present disclosure, it is worth noting that the support frame 5 may be made in a single piece as shown in figure 1, or, as shown in figure 2, it can comprise one first 5a and one second component 5b separated from each other.
In the case shown in figure 2, the first glass 2 is associated to the first component 5a and the second glass 3 is associated to the second component 5b. Still in the case shown in figure 2, the gap 51 is defined when the shielding system 1 is applied to the building.
It is also worth noting that the shielding system 1 can be associated to the building by the support frame 5.
According to a preferred aspect the frame 5 realises a so called sealed gap or, in alternative, a partially or totally ventilated gap.
In other words, when the shielding system 1 is applied to the building, such gap 51 allows that an air flow from the outer environment or from an interior of the building can flow into the gap itself (in the at least partially ventilated or completely ventilated instance) or does not allow any air flow exchange with the outer and/or inner environment (in the sealed instance).
According to a preferred embodiment, the support frame 5 comprises a lower portion 52 and an upper portion 53, each one fixable to a respective building slab 7, such that such shielding system 1 is interposed between two slabs 7.
For example, as shown in figure 3, the lower portion 52 and the upper portion 53 are fastened to a respective slab 7 of the building.
According to a characteristic aspect, the shielding system 1 comprises a sun ray protection device 4 inserted in the gap 51. Such protection device 4 is interposed between the first glass 2 and the second glass 3.
Preferably, as shown in figure 1, such protection device 4 is fixed to the support frame 5 by fixing means known to the person skilled in the art.
Alternatively, as shown in figure 2, the protection device 4 is fixed by a further frame 5c to the building slabs 7.
Such protection device 4 has the function of shielding the building interior. In fact the sun ray protection device 4 defines:

a plurality of transparent areas 41 to let sun rays pass. Such plurality of transparent areas 41 allow sun rays to pass with a certain incidence angle while sun rays having other incidence angles are not able to pass through said plurality of transparent areas 41;
a plurality of blind areas 42 configured not to let sun rays pass.

Such blind areas 42 thus have the function of shading the building inner environment, i.e. not to let sun rays pass .
In case the protection system 1 comprises one first glass 2 and one second glass 3 (i.e. the one free from PVD coating), it derives that blind areas 42 identify a first surface 421 facing the second PVD coating-free glass 3 and one second surface 422 opposite to the first surface 421. The second surface 422 therefore faces the first glass 2.
Once the shielding system 1 is applied to the building the first surface 421 is visible from outside the building. In other words, once the shielding system 1 is applied to the building the first surface 421 faces the building outer environment, while the second surface 422 faces the building interior.
Preferably, the transparent areas 41 are arranged relative to the blind areas 42 following geometric patterns known to the person skilled in the art such as a chessboard arrangement, or a grid, or with longitudinal or vertical bands, or as result of a weft and warp of a textile material.
Still preferably, the ratio between transparent areas 41 and blind areas 42 is determined based on the level of sun ray shading which is desired in the building interiors.
The plurality of blind areas 42 has a reflection index in the visible ρ_v lower than 50% and has a reflection index of sun rays ρ_e greater than the reflective index in the visible ρ_v
The reflection index in the visible ρ_v and the reflection index of sun rays ρ_e are declared according to the standard UNI EN410.
In other words, advantageously, the plurality of blind areas 42, in addition to shading the building interior, i.e. not allowing the passage of sun rays, also have reflective properties in the near infrared.
Still in other words, the plurality of blind areas 42 is able to reflect sun rays in the near infrared, i.e. the component in the near infrared of the sun radiation.
Sun rays in the near infrared means waves emitted by the sun with a wavelength in the range comprised between 780nm-2500nm. Such sun rays do not contribute to lighting but they convey heat. The reflection of such sun rays in the near infrared, by the plurality of blind areas 42, makes possible to prevent the overheating of the building interiors.

I° embodiment of the blind areas 42: reflective dark paint

According to a first embodiment of the invention, at least a portion of the first surface 421 of the plurality of blind areas 42 comprises a layer of dark paint 423.
Preferably, the layer of dark paint 423 covers entirely the first surface 421 of the plurality of blind areas 42.
The layer of dark paint 423 is applied to the first surface 421 of the plurality of blind areas 42 by means of techniques known to the person skilled in the art. The layer of dark paint 423 at least partially reflects sun rays in the near infrared.
Still according to the first embodiment, the layer of dark paint 423 which at least partially reflects sun rays in the near infrared comprises a pigment reflecting sun rays in the near infrared.
For instance, the sun ray protection device 4 may be in the form of:

- a venetian blind (not shown) having a plurality of slats each of which identifies a blind area 42 on which the dark paint is arranged 423,
- or a grid (not shown) having a plurality of longitudinal and transversal shafts, each of which identifies a blind area 42 on which the dark paint 423 is arranged,
- or a holed or pressed plate (not shown) having a frame which defines a plurality of holes, each of which defines a transparent area 41 and the frame identifies the blind area 42 on which the dark paint 423 is arranged,
or a textile material (such as a curtain or a canvas) wherein at least crossing points of weft and warp comprise the dark paint 423;
- or a film.

In case, for instance, the slats are to be moved, the protection device 4 also comprises holding means (not shown) which can be in the form of at least two cords necessary to move the slats by control mechanisms.
According to an aspect the layer of dark paint 423 comprises a pigment reflecting sun rays in the near infrared.
Figure 4 shows a diagram, obtained with experimental tests carried out by the Applicant, of the reflection spectrum of the shielding system 1 wherein the blind areas 42 comprise the dark paint 423 with reflective properties in the near infrared.
The diagram shown in figure 4 has on the abscissa axis the wave length expressed in nanometre (nm) while on the ordinate axis the reflection expressed in percentage (%).
It can be noted from the diagram shown in figure 4 that such shielding system 1 and in particular such blind areas 42 with a dark paint 423 show a medium-low reflection in the visible wavelengths (380nm-780nm) and a higher reflection for wavelengths in the near infrared (780nm-2500nm). It derives that such blind areas 42 with dark paint 423 are able to properly reflect rays in the near infrared.

II° embodiment of the blind areas 42: reflective dark material

According to a second embodiment of the invention alternative to the first embodiment, at least a portion of the first surface 421 of the plurality of blind areas 42 comprises a dark material having reflective properties in the near infrared, i.e. having a reflection in the visible ρ_e lower than 50% and having a reflection index of sun rays higher than the reflection index in the visible ρ_v
Preferably, the dark material with reflective properties in the near infrared covers entirely the first surface 421 of the plurality of blind areas 42.
In this second embodiment it is provided that the venetian blind (not shown), the grid (not shown), the holed or pressed plate, the curtain or canvas and the film rather than having the near infrared-reflective dark paint, are made of a near infrared-reflective dark material.

Claims

A system (1) for shielding sun rays comprising:
- at least a first glass (2);

- a supporting frame (5) for forming a gap (51);

- at least a second glass (3) that is free from PVD coating;

- said first glass (2) and said second glass (3) being each other associated by means of said supporting frame (5);

- a sun ray protection device (4) that is inserted into said gap (51), said sun ray protection device (4) defining:
- a plurality of transparent areas (41) for letting sun rays pass through, said plurality of transparent areas (41) enabling sun rays to pass with a certain incidence angle while sun rays having other incidence angles are not able to pass through said plurality of transparent areas (41);

- a plurality of blind areas (42) identifying one first surface (421) facing the second glass (3) that is free from PVD coating and one second surface (422) opposite to the first surface (421);

- said plurality of blind areas (42) having a reflection in the visible (ρ_v) lower than 50% and having a reflection index of sun rays (ρ_e) higher than the reflection index in the visible (Pv);
characterised in that:
said blind areas (42) are configured not to let sun rays pass though; and

at least a portion of said first surface (421) of said plurality of blind areas (42) comprises a dark material with reflective properties in the near infrared, or a layer of dark paint (423), said layer of dark paint (423) being at least partially reflecting sun rays in the near infrared.
The shielding system (1) according to claim 1, wherein said layer of dark paint (423) comprises a pigment reflecting sun rays in the near infrared.
The shielding system (1) according to claim 1, wherein said light ray protection device (4) comprises a venetian blind having a plurality of slats each of which identifies said blind area (42) on which the dark paint is arranged (423), or a grid having a plurality of longitudinal and transversal shafts, each of which identifies said blind area (42) on which the dark paint is arranged (423), or a holed or pressed plate having a frame which defines a plurality of holes, each of which defines said transparent area (41) and the frame identifies the blind area (42) on which the dark paint is arranged (423), or a textile material wherein at least crossing points of weft and warp identify said blind area (42) and comprise the dark paint (423) or a film.
The shielding system (1) according to any one of claims 1 to 3, wherein said gap (51) is sealed, or at least partially ventilated with respect to the outer environment.