FR3045597A1 - GLAZING WHOSE TRANSPARENCY TO INFRA-RED ADAPTS TO THE HEIGHT OF THE SUN - Google Patents

Abstract

In order to vary the infrared transmission coefficient (5) of a window (1) transparent to visible light, and so that this coefficient is greater in winter when the sun (S) is low and less important in summer when the sun (S) is high, said glazing (1) comprises at least a first planar face (21) and a second planar face (22), said planar faces (21,22) are parallel to each other and on each of which strips of thin layers (3,4) of a material transparent to visible light have been deposited, said strips of thin layers (3,4) are arranged relative to each other to form a network of parallel bands (3, 4) between them and the infrared radiation transmission coefficient of said thin-film bands (3, 4) is less than the transmission coefficient of the infra-red radiation of the space (2) between said first planar face (21) and said second planar face (22) so that the v itration (1) becomes even less transparent to infrared incident radiation (5) that the overall surface of said bands (3,4) which intercept the infra-red radiation (5) is important.

Description

GLAZING WHOSE TRANSPARENCY TO INFRA-RED ADAPTS TO THE HEIGHT OF THE SUN

The present invention relates to solar control glazing.

STATE OF THE ART

In order to minimize the energy needs of buildings and obtain good thermal comfort, it is common to use special glazing, called solar control glazing or low emissivity glazing (Low-e in English language). These windows have a very low solar factor (g <0.38) which allows them to greatly reduce the risk of overheating in summer and in off-season when the windows are exposed to the sun. In winter, thanks to a very low thermal transmittance (Ug <1.0 W), they provide excellent insulation to keep the heating heat inside the premises.

Solar control glazing generally contains two or three panes separated by an air gap or a low thermal conduction gas, and at least one of the faces (usually the second face) is treated by the deposition of a thin layer or by sputtering a thin transparent layer of noble metals, such as silver, in order to reflect the infra-red radiation and thus reduce the solar energy intake in summer, while maintaining good transparency in visible light. The disadvantage of solar-controlled glazing is that the reflection of infrared solar energy (solar control) to the outside of the home is independent of the season. The reduction of the solar energy supply works as well in winter as in summer whereas it would be very advantageous to control this energy supply according to needs.

Automated solar control glazing already exists, but they use expensive expensive electrically controlled liquid crystal materials or opacifying films that tint more or less depending on brightness or heat. In addition, these windows do not convert the excess infrared energy into electricity.

OBJECT OF THE INVENTION The purpose of the invention is to describe a glazing structure with a lower manufacturing cost, the transmission coefficient of solar infrared varies according to the seasons, which will allow to pass part of the infra-red solar energy in winter to bring heat to the local and reflect infra-red solar energy in the summer to reduce overheating of the same room. On the other hand, it would be advantageous to capture and convert into electricity the infra-red energy that does not cross the glazing, which would contribute to improving the energy balance of buildings.

SUMMARY OF THE INVENTION

The term "glazing" is defined hereinafter by an assembly of one or more panes, made of crystalline glass or organic glass, possibly curved, of any shape, with holding or consolidation structures of all types and using all types of materials, said windows being integrated in all types of buildings, transport vehicles, devices containing windows, doors or openings.

Hereinafter, the term "near infra-red" and more simply the term "infrared" is defined by the range of wavelengths between 0.7 and 2.1 microns and the term "far infra-red". by wavelengths greater than 2.1 microns.

It is important to note that it is generally desirable to limit all the more infra-red radiation from the sun as it is high above the horizon. The link between the outside air temperature and the height of the sun is fairly good regardless of the season and regardless of the geographical location. The glazing according to the invention takes this remark into account and makes it possible to vary the percentage of transmission of infra-red radiation from the sun as a function of the height of the sun relative to the horizon.

The glazing according to the invention is predominantly transparent to visible light and comprises at least a first planar face and a second planar face, said planar faces are parallel to each other and on each of them have been deposited thin-film strips. a material transparent to visible light. Said thin film strips are arranged relative to each other to form a network of strips parallel to each other. The glazing according to the invention is characterized in that the transmission coefficient of the infra-red radiation of said strips of thin layers is less than the transmission coefficient of the infra-red radiation of the space between said first planar face and said second face. plane.

The incident visible light passes through said glazing and for a portion passes through said strips in thin layers without overall loss of intensity. But the infra-red radiation, at the passage of said glazing, will meet either the strips of the first face and be reflected or absorbed, or meet the strips of the second face and be also reflected or absorbed, or meet any of the bands and pass through said glazing without being absorbed or reflected.

The proportion of infra-red radiation that passes through the glazing without encountering said strips, and therefore without being intercepted, depends on several parameters including fixed parameters: the width of the strips, the distance between the strips, the distance between said first face and said second face, and a variable parameter: the height of the sun above the horizon. For example, it can be shown that when the glazing is in a vertical position and the infra-red strips are in a horizontal position with this characteristic that each strip of said first face is positioned opposite each corresponding strip of said second face, then the glazing is at maximum of its transparency to infrared when the sun is on the horizon and at least transparency when the sun is at its maximum height.

The maximum of the height of the sun above the horizon occurs at the summer solstice during the passage of the sun to the meridian of the place (in the South when one is in the northern hemisphere). The adjustment of the fixed parameters of the glazing, in particular the distance between said first face and said second face, makes it possible to adjust the transparency at the infra-red of the glazing so that it is at its lowest value at the time of the summer solstice. and the most important when the sun is on the horizon. Thus the control of the infra-red radiation transparency will be as well during the hours of the day according to the height of the sun as during the seasons according to the maximum height of the sun.

In a particular embodiment of the invention, the distance between said first and said second face, the width of said strips of thin layers and the distance between said strips of thin layers are such that, for a fixed position of said glazing, the transparency average of said glazing infra-red radiation emitted by the sun is even lower than the position of the sun is raised above the horizon.

In a particular embodiment of the invention, said strips of thin layers are not visible to the naked eye. This non-visibility is made possible for example by choosing a coefficient of transparency of the glass spaces located between said infra-red bands which is substantially identical to that of said infra-red bands, or by making strips whose width is less than one hundred microns.

In another particular embodiment of the invention, the space between said first face and said second face is filled with a gas, possibly air, or a mineral or organic glass. In the case where said space is glass whose refractive index is of the order of 1.5, a phenomenon of refraction of the infra-red radiation occurs between the two faces, which deviates the angle of incidence of said radiation before passing through said second face. A slight shift in the positioning of the strips of the second face relative to the positioning of the strips of the first face is then necessary to restore the desired coefficient of infrared transmission according to the height of the sun.

In a particular embodiment of the invention, it may be advantageous that said glazing further comprises on some of its faces coatings which make said reflective and / or absorbent faces for part of the solar spectrum. It is for example interesting to treat at least one of the faces of the glazing against ultraviolet radiation.

In another particular embodiment of the invention, said strips of thin layers are composed of a stack of several thin layers whose reflection and / or absorption coefficients are different with respect to infra-red radiation. Thus it may be interesting to have the bands of the first face, that is to say those which receive the first solar radiation, composed of a first thin layer rather reflective to infra-red and a second layer thin rather absorbent infrared, so that the infrared radiation which is reflected by the strips of the second face is absorbed by the absorbent layer of the strips of the first face and not again reflected by said strips of the first face to said second face, which in this case would have the disadvantage and make the glazing globally more transparent infrared.

In a particular embodiment, said strips of thin layers are positioned horizontally. This particular case is particularly interesting when glazing must be integrated into a building facade, a greenhouse, a building roof, a veranda, a transport vehicle, street furniture, a screen or a billboard. that is, when the glazing is preferably in a vertical position.

In a particular advantageous embodiment, said glazing contains photovoltaic cells not visible to the naked eye; this is the case, for example, of micro-photovoltaic cells in strips whose width is less than 100 microns.

In a particular embodiment that is even more advantageous, said strips of thin layers have the property of redirecting the energy of the infra-red radiation, and possibly the ultraviolet radiation, into the thickness of said glazing unit by means of multiple reflections of the same type. refraction on the faces of said glazing, and to photovoltaic cells positioned at the periphery of said glazing so as to transform the energy of said infra-red radiation into photovoltaic electricity.

DETAILED DESCRIPTION OF THE INVENTION The invention is now described in more detail with the aid of the description of the indexed FIGS. 1 to 4.

Figure 1 shows in section a window (1) according to the invention and the path of solar radiation (5) when the sun (S) is rather low above the horizon (H).

Figure 2 shows in section the window (1) of Figure 1 above and the path of solar radiation (8) when the sun (S) is rather high above the horizon (H).

Figure 3 shows the particular case where the space (2) between the two faces (21,22) of the glazing (1) is filled with air.

FIG. 4 schematically represents a particular embodiment in which the infra-red radiation is redirected towards the periphery of the pane (1) and transformed into electricity by photovoltaic cells (13).

The glazing unit (1) according to the invention is composed of at least two parallel plane faces (21,22) each covered with an array of parallel strips (3,4) which absorb or reflect infra-red radiation (5) of the sun (S). The longitudinal axis of said infra-red strips is preferably positioned horizontally. The distance between the two faces (21,22) is equivalent in this example to the thickness of the window (1) and the space between these two faces is filled with mineral glass or organic glass, the glass and the strips are very transparent to visible light. The height positioning of the first network of bands (3) with respect to the second network of bands (4) is chosen so that the angle A1 that the infra-red radiation (5) makes with the horizontal (H) produces a maximum transmitting infra-red radiation (6) through the window (1) when the sun (S) is low on the horizon, so when the angle Al is low. Indeed, part of the infrared radiation (5) is reflected (7) by the strips (3) of the first face (21) towards the outside of the window (1) and the other part (6) passes through the window ( 1) by intercepting very little or not at all the strips (4) of the second face (22) because said bands (4) are in the shade of the strips (3) of the first face (21).

The transmission coefficient of the infra-red radiation (5) through the window (1) in this configuration (low sun) then depends on the ratio between the overall surface of the strips (3) of the first face (21) and the surface total of the first face (21). This infra-red transmission coefficient may be greater than 50%.

FIG. 2 shows the same characteristics of the window (1) of the preceding FIG. 1, but this time the sun (S) is in the high position, that is to say that the angle A2 that the solar radiation ( 8) with respect to the horizon (H) is greater than the angle Al that the solar radiation (5) did when the sun (S) was in the low position. The highest position of the sun (S) is when the sun passes the meridian of the place (south) at the time of the summer solstice. The infra-red radiation (8) is reflected in part by the band network (3) of the first face (21), in the same proportion as when the sun was in the lower position (Figure 1), but this time the infra-red radiation is intercepted (absorbed or reflected, 10) partially or completely by the strips (4) of the second face (22), so that a very small portion of the infra-red radiation (8) passes through the window (1) while said window (1) remains very transparent to the visible radiation (9).

When the height of the sun (S) is between its lowest value (Al = 0 at the horizon H) and its highest value (A2 = 90 - latitude of the place, at noon at the solstice), the transparency of the window (1) infrared radiation varies gradually from a maximum value to a minimum value, said values being a function of the width of the bands (3,4) and the distance between the two networks of strips.

FIG. 3 represents a particular embodiment in which the glazing unit (1) is composed of two parallel panes (11, 12) separated by an air knife (2). This configuration is often called a "double" glazing and has the advantage of being much more thermally insulating than a single glazing. In this configuration, said first face (21) and said second face (22) which respectively support the first network of strips (3) and the second network of strips (4) are positioned on the faces number two and number three of the double glazing , it being understood that the numbering of the faces begins with the outer face of the glazing unit which receives the solar radiation first. The other advantage of this configuration is that the infrared bands (3, 4) are thin layers that are often quite sensitive to humidity and that positioning them in the protected space of the double glazing increases their service life. .

FIG. 4 represents a particular embodiment that makes it possible to transform the infra-red radiation (5) reflected by the bands (3, 4) into electricity. The technique used to absorb infra-red and then re-emit in a slightly different wavelength range is already known (US Patent 2014/0283896 A1). The re-emitted radiation propagates in the thickness of a transparent plate by multiple total reflections on the walls of said window pane and to the periphery edges where photovoltaic cells (13) are positioned which transform the radiation energy into electricity. . The embodiment of FIG. 4 is new because the material that allows the infra-red frequency jump is not evenly distributed on the surface of the glazing, but is distributed according to a network of parallel strips (3, 4) arranged on two parallel faces (21,22) of the glazing unit (1), which allows said glazing (1) to be more or less transparent to the infra-red (5) as a function of the angle of incidence of said infra-red rays; red (5) and transform into electricity the infra-red radiation re-emitted (14,15) through photovoltaic cells (13) positioned peripherally on the edges of the glazing (1).

EXEMPLARY EMBODIMENT

An exemplary embodiment is shown schematically in FIG.

A double glazing (1) is composed of panes (11 and 12) in clear mineral glass 4 mm thick and spaced 9 mm. A material transparent to visible light, reflecting 85% of the near infra-red radiation and comprising nanometric silver particles, is deposited in thin layers of 2 microns and forms a network of parallel strips (3, 4) of 9 mm. wide and spaced 9 mm apart. Said bands (3,4) are positioned horizontally on the two inner faces (21,22) of the double glazing (1) so that the strips (3) of the first face (21) are offset in height by a value of 2 mm with respect to the strips (4) of the second face (22).

It is then shown that the transmission coefficient of the infra-red solar radiation of said double glazing (1) decreases approximately 60% to 15% when, at a latitude of 45 degrees, when the sun goes from its lowest position to its position the highest (summer solstice), which regulates the heat input of solar radiation that passes through the glazing according to the seasons and limit heat loss (far infrared) thanks to the low thermal transmittance double glazing.

ADVANTAGES OF THE INVENTION

Ultimately the invention responds well to the goals set by allowing, passively, and at a lower cost, to vary the transmission coefficient of solar infra-red glazing according to the seasons, in order to pass part of the infra-red solar energy in winter and reflect a lot of infra-red solar energy in the summer to regulate the temperature of buildings.

Claims (10)

1 - Glazing (1) predominantly transparent to visible light comprising at least a first planar face (21) and a second planar face (22) separated from one another by a space (2), said flat faces (21 and 22) being parallel between them and on each of them being deposited thin-film strips (3 and 4) of a material transparent to visible light, said strips of thin layers (3,4) being arranged relative to each other to form a network of strips parallel to each other, characterized in that the transmission coefficient of the infra-red radiation of said strips of thin layers (3,4) is chosen to be lower than the transmission coefficient of the infra-red radiation of said space (2) . 2 - glazing (1) according to claim 1, characterized in that the distance between said first (21) and said second (22) face, the width of said strips of thin layers and the distance between said strips of thin layers are chosen such that, for a fixed position of said glazing (1), the average transparency of said infrared radiation glazing (5) emitted by the sun (S) is even lower than the position of the sun is raised above the horizon (H). 3 - glazing (1) according to claim 1 or claim 2, characterized in that said strips of thin layers (3,4) are not visible to the naked eye, for example by choosing a transparency coefficient glazed spaces located between said infra-red bands which is substantially identical to that of said infra-red bands. 4 - Glazing (1) according to one of the preceding claims, characterized in that the space (2) between said first face (21) and said second face (22) is filled with a gas, optionally the air, or by a mineral or organic glass. 5 - Glazing (1) according to one of the preceding claims, characterized in that said glazing (1) further comprises on some of its faces coatings that make said reflective and / or absorbent faces to a portion of the solar spectrum. 6 - glazing (1) according to one of the preceding claims, characterized in that said strips of thin layers (3,4) are composed of a stack of several thin layers whose reflection coefficients and / or absorption of infrared radiation are different from each other. 7 - glazing (1) according to one of the preceding claims, characterized in that said strips of thin layers (3,4) are positioned horizontally. 8 - Glazing (1) according to one of the preceding claims, characterized in that said glazing (1) contains photovoltaic cells not visible to the naked eye, such as micro-photovoltaic cells in strips whose width is less than one hundred micrometers. 9 - Glazing (1) according to one of the preceding claims, characterized in that said strips of thin layers (3,4) have the property of redirecting the energy of the infra-red radiation (5), and possibly ultraviolet radiation -violet, in the thickness of said glazing (1) by multiple refraction index jump type reflections on the faces of said glazing (1) and to photovoltaic cells (13) positioned at the periphery of said glazing (13), transforming the energy of said infra-red radiation (5) into photovoltaic electricity. 10 - Glazing (1) according to one of the preceding claims, characterized in that said glazing (1) is integrated in a building facade, a greenhouse, a roof of building, a veranda, a transport vehicle, a street furniture, a screen or a billboard.