Insulating glazing

Abstract

The present invention concerns a triple glazing unit comprising three glass panes, an outer glass pane defining an outer surface bounded by an outer glass pane perimeter, inner glass pane defining an inner surface bounded by an inner glass pane perimeter, an intermediate glass pane defining an intermediate surface bounded by an intermediate glass pane perimeter, the outer and intermediate glass panes being separated from one another by a first gap defined within a first peripheral spacer, the inner and intermediate glass panes being separated from one another by a second gap defined within a second peripheral spacer, wherein the first and second peripheral spacers follow the perimeter of the outer and inner glass panes respectively, the intermediate surface covers at least the entirety of the inner and outer surfaces and the intermediate surface is larger than at least one of the outer and inner surfaces and a part of the intermediate glass pane, the intermediate extension, extends beyond at least one of the outer and inner surfaces, characterized in that the differences Δo and / or Δi between the energetic absorptance of the intermediate glass pane (102) AEint and the energetic absorptance of the inner AEi and / or outer glass pane AEo (101, 103), where Δo=AEint-AEo and Δi= AEint-AE, are greater than 10%, preferably greater than 15%, more preferably greater than 20%, even more preferably greater than 30%.

Description

DescriptionInsulating glazingTechnical field

[0001] The present invention concerns a triple glazing unit comprising three glass panes, wherein the intermediate glass pane is larger than one or both of the outer and inner glass panes that may improve the thermal management of a building.Background art

[0002] Triple glazing units (TGUs) are today’s standard highly insulating glazing type. As is well known, in triple glazing units, comprising in sequence an outer glass pane, an intermediate glass pane, and an inner glass pane, the intermediate glass pane may reach high temperatures when submitting TGUs to solar radiation.

[0003] Intermediate glass panes having high temperatures add thermal strain on the glazing, therefore in traditional TGUs energetic absorption in the intermediate glass pane is usually kept as low as possible.

[0004] Furthermore, the inventors found that heat absorbed by the intermediate glass pane is not used efficiently as it re-emitted both outwards and inwards. For example, in winter part of it is lost by radiation towards the building’s outside and in summer it even contributes to overheating by radiating towards a building’s interior.

[0005] One aim of the present invention is to provide a triple glazing unit wherein the energy absorbed by the intermediate glass pane can contribute to the thermal management of a building wherein it is installed, in particular by selectively increasing or reducing the contribution of the heat absorbed by the intermediate glass pane to the heating of a building.Summary of invention

[0006] The present invention concerns a triple glazing unit comprising three glass panes, a. an outer glass pane defining an outer surface bounded by an outer glass pane perimeter,b. an inner glass pane defining an inner surface bounded by an inner glass pane perimeter, c. an intermediate glass pane defining an intermediate surface bounded by an intermediate glass pane perimeter, the outer and intermediate glass panes being separated from one another by a first gap defined within a first peripheral spacer, the inner and intermediate glass panes being separated from one another by a second gap defined within a second peripheral spacer, wherein the first and second peripheral spacers follow the perimeter of the outer and inner glass panes respectively, the intermediate surface covers at least the entirety of the inner and outer surfaces and the intermediate surface is larger than at least one of the outer and inner surfaces and a part of the intermediate glass pane, the intermediate extension, extends beyond at least one of the outer and inner surfaces, and wherein the differences Aoand / or A between the energetic absorptance of the intermediate glass pane AEint and the energetic absorptance of the inner AEi and / or outer glass pane AE0, where A0=AEint-AE0and A = AEint-AE, are greater than 10%, preferably greater than 15%, more preferably greater than 20%, even more preferably greater than 30%.

[0007] The inventors have found that a TGU of the present invention may reduce the temperature of the intermediate glass pane when exposing the TGU to sunlight. Thereby thermal stress on the TGU may be reduced. It was found that by providing an intermediate surface that is larger than at least one of the outer and inner surfaces such that a part of the intermediate glass pane, the intermediate extension, extends beyond at least one of the outer and inner surfaces, a surface of the intermediate glass pane is exposed and made available for heat exchange, in particular by convection. Thus the temperature of the intermediate glass pane may be reduced.

[0008] Additionally, heat absorbed by the intermediate glass pane may be used to heat the interior of a building or may be dissipated towards the exterior for example to reduce the risk of overheating of a building.

[0009] The inventors have also found that by increasing the energetic absorption of the intermediate glass pane, in particular the share of the intermediate glass pane in the TGU’s total energetic absorption, a larger amount of heat can be redirected towards the outside or inside of a building depending on thermal management needs.Brief description of drawings

[0010] These and further aspects of the invention will be explained in greater detail by way of example and with reference to the accompanying drawings in which: a. Fig. 1 a and Fig. 1 b are schematic cross-sectional side views of a triple glazing in accordance with certain embodiments of the present invention, b. Fig. 2 is a schematic 3D view of Fig. 1a embodiment, c. Fig. 3 and Fig. 4 are schematic 3D views of triple glazings according to certain embodiments of the present invention with heat transfer means, d. Fig. 5 is a schematic view of a triple glazing according to certain embodiments of the present invention, e. Fig. 6 is a schematic view of a triple glazing according to certain embodiments of the present invention.

[0011] The Figures are not drawn to scale.Detailed description of embodiments

[0012] Each glass pane of the invention has 2 main faces bonded by minor faces, which are the edges of the glass pane and each glass pane has a surface. By surface of a glass pane is meant the 2D area occupied by the glass pane, which may for instance be measured in square meters. The inner surface is the surface of the inner glasspane, the outer surface is the surface of the outer glass pane and the intermediate surface is the surface of the intermediate glass pane.

[0013] The intermediate glass pane has a first face, the outer face, turned towards the outer glass pane and second face, the inner face, turned towards the inner glass pane. Similarly, the part of the intermediate glass pane, named intermediate extension, extending beyond at least one of the outer and inner surfaces, has an outer face and / or inner face, which are the parts of the intermediate glass pane’s outer face and / or inner face extending beyond the outer and / or inner surfaces respectively.

[0014] The intermediate glass pane has an energetic absorption higher than at least one of the outer and / or inner glass panes. Glass pane energetic absorptions may be adjusted by the energetic absorption of a glass substrate used, it’s tint and thickness, by the use of polymer interlayers, and / or also by the choice of the coatings deposited on the glass substrate.

[0015] In the present invention, energetic absorption and energetic absorptance may be used interchangeably and refer to the solar direct absorptance of the glass pane as defined in EN410:2011.

[0016] The energetic absorptance EA of the intermediate glass pane is at least 10% higher, preferably at least 15% higher, more preferably at least 20% higher, even more preferably at least 30% higher than the energetic absorptance of the inner and / or outer glass pane. In other words, the differences Aoand / or A between the energetic absorptance of the intermediate glass pane (102) AEint and the energetic absorptance of the inner AEi and / or outer glass pane AE0(101 , 103), where A0=AEint-AE0and A = AEint-AEi, are greater than 10%, preferably greater than 15%, more preferably greater than 20%, even more preferably greater than 30%.

[0017] In an embodiment of the present invention, the energetic absorptance of the inner and / or outer glass panes is at most 20%, preferably at most 15%.

[0018] In an embodiment of the present invention, energetic absorptance of the intermediate glass pane is at least 25%, preferably at least 30%.

[0019] In an embodiment of the present invention, the first and second gaps are hermetically separated from each other and also from the air surrounding the glazing unit.

[0020] In an embodiment of the present invention, the intermediate extension extends beyond one or more of the edges of the outer and / or inner surfaces.

[0021] In an embodiment of the present invention, the intermediate extension extends at least beyond the uppermost edge of the outer and / or inner surfaces. Here within, the uppermost edge being the edge configured to be above the other edges when the glazing is installed in a building.

[0022] Typically, peripheral spacers contact two glass panes, comprise a desiccant and have a thickness of at least 6 mm. In general, each gap is filled with a gas which may be selected from the group consisting of air, dry air, argon (Ar), krypton (Kr), xenon (Xe), sulfur hexafluoride (SF6), carbon dioxide or a combination thereof. Said predetermined gas are effective for enhancing thermal insulating performances and / or may be used to reduce sound transmission. Preferably the gas within each gap comprises at least 50% Ar or Kr as such noble gases considerably improve insulation properties. Maintaining sealed gaps in between glass panes is crucial for obtaining good insulation properties.

[0023] In an embodiment of the present invention, the intermediate extension extends up to a distance of at least 5cm, 7cm, 8cm or even 10cm beyond at least one of the edges, for example the uppermost edge, of the outer and / or inner surfaces. This distance may be adapted, for example made larger for larger glass panes as a larger intermediate extension may provide a larger heat exchange area.

[0024] The glass panes in the present invention may be single glass substrates or two or more glass substrates assembled by polymer interlayers, in particular thermoplastic interlayers.

[0025] Light transmission (LT) is the percentage of incident light flux, illuminant D65 / 2°, transmitted by the glazing. Light transmission and light transmittance are herein used interchangeably. Energy transmission (ET) is the percentage of incident energyradiation transmitted by the glazing calculated in accordance with standard EN41 0:2011. Energy reflection (ER) is the percentage of incident energy radiation reflected by the glazing calculated in accordance with standard EN410:2011. It may be measured on the external side of the building (ERext) or the internal side of the building or vehicle (ERint). Solar factor (SF or g) is the percentage of incident energy radiation that is directly transmitted by the glazing, on the one hand, and absorbed by this, then radiated in the opposite direction to the energy source in relation to the glazing. It is here calculated in accordance with standard EN410:2011. The U value (coefficient k) and emissivity (E) are calculated in accordance with standards EN673:2011 and ISO 10292:1994.

[0026] In an embodiment of the present invention the light transmittance of the triple glazing unit is at least 30%, preferably at least 40%, more preferably at least 50%.

[0027] In an embodiment of the present invention, the intermediate glass pane comprises a tinted glass substrate. In particular the intermediate glass pane may consist of a single tinted glass pane.

[0028] In an embodiment of the present invention the intermediate glass pane comprises two glass substrates assembled by a polymer interlayer, in particular a thermoplastic interlayer such as for example polyvinylbutyral (PVB) or ethylvinylacetate (EVA). Even if the two assembled glass substrates are clear or extra-clear glass substrates, energetic absorption values for the intermediate glass pane that are for example higher than the energetic absorption of the inner and / or outer pane, may be obtained by using a sunlight absorbing polymer interlayer.

[0029] According to an embodiment, the polymer interlayer to be used in an intermediate glass pane of the present invention may be a transparent or clear polymer interlayer. However, in order to enhance the energetical absorptions, it is preferred that the polymer interlayer is colored or patterned. In particular, the polymer interlayer may be a grey PVB

[0030] In an advantageous embodiment of the present invention, the intermediate glass pane has a thickness of at least 4mm, more advantageously of at least 6mm or even more advantageously of at least 8mm. Energy absorption may be increased byincreasing the glass pane thickness.

[0031] In an embodiment of the present invention, the intermediate glass pane comprises a first functional coating on at least part of its outer face and / or a second functional coating on at least part of its inner face. Preferably the intermediate extension’s outer and / or inner faces are devoid of any functional coating.

[0032] In an embodiment of the present invention, the inner glass pane comprises a third functional coating on the face oriented towards the intermediate glass pane.

[0033] In an embodiment of the present invention, the outer glass pane comprises a fourth functional coating on the face oriented towards the intermediate glass pane.

[0034] The functional coatings are infrared (IR) reflecting and / or absorbing coatings, for example solar control coatings or low-emissivity (lowE) insulating coatings. The position and nature of the functional coating may be adapted according to thermal management needs, for example for increased insulating properties in colder regions or for increased solar control needs in hotter regions.

[0035] Functional coatings may comprise a transparent conductive oxide or comprise at least one functional, infrared reflecting, layer comprising silver, and include one or more layers, and in many embodiments it may be multilayer coating. Low-emissivity functional coatings for example includes at least one infrared (IR) reflecting layer (e.g., based on silver) sandwiched between at least first and second dielectric layers. Since one example function of low-emissivity coatings is to block certain amounts of IR radiation and prevent the same from reaching the building interior, the solar management coatings may include at least one IR blocking (i.e., IR reflecting and / or absorbing) layer. Example IR blocking layer(s) which may be present in coatings are of or include silver (Ag), nickel-chrome (NiCr), gold (Au), and / or any other suitable material that blocks significant amounts of IR radiation. It will be appreciated by those skilled in the art that IR blocking layer(s) of low-E coating need not block all IR radiation, but only need to block significant amounts thereof. In certain embodiments, each IR blocking layer of coating is provided between at least a pair of dielectric layers. Example dielectric layers include silicon nitride, titanium oxide, silicon oxynitride, tin oxide, zinc stannate, and / or other types of metal-oxides and / or metal-nitrides. Incertain embodiments, in addition to being between a pair of dielectric layers, each IR blocking layer may also be provided between a pair of contact layers of or including a material such as an oxide and / or nitride of nickel-chrome or any other suitable material. Example low-emissivity coatings which may be provided on substrates are described in Patents W003106363A1 , W02004071984A1 , W02006048462A1 , W020091 15595A1 , W02009115596A1 , W02009115599A1 , W02006048463A1 , W02006067 102A1 , W02006122900A1 , W02007138097A1 , W02008113786A1 , WO201 1147875A1 , WO2011147864A1 , W02013079400A1 , WO2014191472A1 , WO2014191474A1 , WO2014191484A1 , W02014125081A1 , WO2014125083A1 , WO201 4207171 A1 , all of which are hereby incorporated herein by reference. Of course, functional coatings herein are not limited to these particular coatings, and any other suitable functional coatings capable of blocking amounts of IR radiation may instead be used. Functional coatings herein may be deposited on substrates in any suitable manner, including but not limited to sputtering, vapor deposition, and / or any other suitable technique.

[0036] In an embodiment of the present invention, the intermediate glass pane is a prestressed glass, for example heat strengthened glass, a thermally toughened, i.e. tempered, safety glass, or chemically strengthened glass.

[0037] Fig. 1 a and 1 b show schematic cross sections of embodiments of triple glazing units according to the present invention, comprising an outer glass pane (101), an intermediate glass pane (102) and an inner glass pane (103). Outer and intermediate glass panes (101 , 102) are separated from one another by a first gap defined within a first peripheral spacer (104). The inner and intermediate glass panes (103, 102) being separated from one another by a second gap defined within a second peripheral spacer (105). In Fig. 1a the intermediate extension (102e), extends beyond the outer surface, exposing thus the intermediate extension’s outer face (102o). In Fig. 1 b the intermediate extension (102e), extends beyond outer and inner surfaces, exposing thus the intermediate extension’s outer face (102o) and inner face (102i).

[0038] Fig. 2 schematically shows a different view of the Fig. 1a embodiment in 3D.

[0039] In an embodiment of the present invention, the intermediate surface is larger thanthe outer surface and a part of the intermediate pane, the intermediate extension, extends beyond the surface bounded by the first peripheral spacer. The intermediate surface may be essentially the same as the inner surface, such that the intermediate surface does not extend beyond the surface bounded by the second peripheral spacer, as represented in Fig. 1a.

[0040] In an embodiment of the present invention, not represented by the Figures, the intermediate surface is larger than the inner surface and a part of the intermediate pane, the intermediate extension, extends beyond the surface bounded by the second peripheral spacer. The intermediate surface may be essentially the same as the outer surface, such that the intermediate glass pane does not extend beyond the surface bounded by the first peripheral spacer.

[0041] In an embodiment of the present invention, the intermediate surface is larger than the inner and outer surfaces and a part of the intermediate pane, the intermediate extension, extends beyond the surface bounded by the first and second peripheral spacers. The surfaces of the inner and outer glass panes may be essentially the same, such as represented in Fig. 1 b, or may be different.

[0042] In an embodiment of the present invention, the triple glazing unit comprises ventilation means configured to allow air passage or air circulation to and / or from the intermediate extension’s outer and / or, separately, the intermediate extension’s inner face. When installed in the opening of a partition defining an exterior space and an interior space, wherein the outer glass pane is facing the exterior space, ventilation means may be configured to allow air passage from the exterior and / or interior space respectively to and / or from the intermediate extension’s outer and / or inner face.

[0043] In an embodiment of the present invention, the triple glazing comprises heat transfer means, affixed to at least one face of the intermediate extension. In other words, the triple glazing unit of this embodiment has an intermediate extension with an outer face turned towards the outer glass pane and / or an inner face, turned towards the inner glass pane and which comprises heat transfer means, affixed to at least one face of the intermediate extension.

[0044] Fig. 3 schematically shows a Fig. 2 embodiment further comprising heat transfermeans (106) affixed to the face of the intermediate extension (102e) extending beyond the outer surface bounded by the first peripheral spacer (104).

[0045] Fig. 4 schematically shows a different view of a Fig. 1 b embodiment further comprising heat transfer means (106, 107) affixed to both faces of the intermediate extension (102e).

[0046] Any heat transfer means herein preferably comprise thermally conductive adhesives, such as for example glues or double sided tapes. Such adhesives improve thermal conduction when heat transfer means are affixed thereby to an intermediate extension.

[0047] Heat transfer means may include a plurality of heat exchange fins. Heat exchange fins enlarge the heat transfer surface thus increasing heat transfer efficiency.

[0048] In an embodiment of the present invention, the ventilation means are outer ventilation means and comprise an outer ventilation cap, coupled to the intermediate extension, the outer glass pane, the first peripheral spacer and optionally to heat transfer means affixed to the intermediate extension’s outer face and advantageously configured to define an outer ventilation gap adjacent the intermediate extension’s outer face. In this manner, an outer ventilation gap is defined within the outer ventilation cap, the intermediate extension part, the first peripheral spacer, the outer glass pane, and optionally the heat transfer means affixed to the intermediate extension’s outer face. The outer ventilation cap may typically comprise metal, wood, polymer, and / or composite material.

[0049] In an embodiment of the present invention, the ventilation means are inner ventilation means and comprise an inner ventilation cap, coupled to the intermediate extension, the inner glass pane, the second peripheral spacer and optionally to heat transfer means affixed to the intermediate extension’s inner face and advantageously configured to define an inner ventilation gap adjacent the intermediate extension’s inner face. In this manner, an inner ventilation gap is defined within the inner ventilation cap, the intermediate extension part, the second peripheral spacer, the inner glass pane, and optionally the heat transfer means affixed to the intermediate extension’s inner face. The inner ventilation cap may typically comprise metal, wood,polymer, and / or composite material.

[0050] In an embodiment of the present invention, the ventilation means comprise outer ventilation means comprising an outer ventilation cap, coupled to the intermediate extension, the outer glass pane, the first peripheral spacer and optionally to heat transfer means affixed to the intermediate extension’s outer face and inner ventilation means comprising an inner ventilation cap, coupled to the intermediate extension, the inner glass pane, the second peripheral spacer and optionally to heat transfer means affixed to the intermediate extension’s inner face.

[0051] In an advantageous embodiment, the outer and / or inner ventilation caps are sealedly coupled to the respective glass panes and spacers. Such coupling may be obtained in an abutting manner and / or in an overlapping manner, for example with a sealing adhesive provided in between coupled parts.

[0052] The inner and outer ventilation caps may form a joined cap or separate caps. They remain configured to allow separate air passages to and / or from the intermediate extension’s outer and / or to and / from the intermediate extension’s inner face.

[0053] In an embodiment of the present invention, the inner and outer ventilation caps are configured to jointly form a frame extending over the whole perimeter of the outer, intermediate and inner glass panes and in particular contacting the exposed faces of the outer and inner glass panes. The frame typically comprises metal, wood, polymer, and / or composite material.

[0054] In an embodiment of the present invention, the ventilation means comprise an outer and / or inner ventilation path configured to allow, air passage or air circulation to and / or from the intermediate extension’s outer and / or inner face. When installed in the opening of a partition defining an exterior space and an interior space, wherein the outer glass pane is facing the exterior space, ventilation paths may be configured to allow air passage from and / or to the exterior and / or interior space respectively to and / or from the intermediate extension’s outer and / or inner face.

[0055] Heat transfer means are preferably positioned in a ventilation path. Thereby increasing the heat exchange rate between the intermediate extension’s faces andthe surrounding air.

[0056] In an embodiment of the present invention, the ventilation means comprise sealing elements configured to separate the outer and inner ventilation paths, that is, the air circulating between the intermediate extension’s outer face and the exterior of the building, from air circulating between the intermediate extension’s inner face and the interior of the building.

[0057] In an embodiment of the present invention, the outer and / or inner ventilation caps comprise respectively at least one outer and / or inner ventilation hole. Outer and / or inner ventilation holes are advantageously configured to allow airflow from the exterior towards the intermediate extension’s outer face as well as from the intermediate extension’s outer face towards the exterior and / or from the interior towards the intermediate extension’s inner face as well as from the intermediate extension’s inner face towards the interior respectively. In particular, the outer and / or inner ventilation caps may comprise a plurality of outer and / or inner ventilation holes.

[0058] In an embodiment of the present invention, each ventilation hole may be configured to allow bi-directional airflow. Each bi-directional outer and / or inner ventilation hole is thus configured to allow airflow from the exterior towards the intermediate extension’s outer face as well as from the intermediate extension’s outer face towards the exterior and / or from the interior towards the intermediate extension’s inner face as well as from the intermediate extension’s inner face towards the interior respectively.

[0059] In an embodiment of the present invention, the ventilation holes comprise inlets and outlets, in particular outer inlets and outlets, and inner inlets and outlets. Ventilation paths are advantageously configured to fluidly connect an inlet, an intermediate extension face and / or heat transfer means affixed thereon, and an outlet.

[0060] Ventilation holes may be shaped so as to promote air flow. Bi-directional holes may extend in a vertical direction, thus configured to allow air inflow near the lower part and air outflow near the upper part of the ventilation holes.

[0061] In an advantageous embodiment, outlets and inlets may be slit shaped. Inparticular they may be configured to be horizontally positioned with the TGU in its installation position.

[0062] According to an embodiment of the present invention the outlets are positioned in a vertical direction above the inlets. In such a configuration, air may circulate by natural convection as air is heated by contacting the intermediate extension’s outer and / or inner face.

[0063] Fig. 5 schematically shows, in a 3D view towards the outer glass pane (101), a triple glazing unit according to an embodiment of the present invention, the outer and inner ventilation caps together (110) form a frame comprising outer inlets (108) and outer outlets (109). Inner inlets and outlets may be similarly present but are not shown here.

[0064] Fig. 6 schematically shows, ventilation caps as they may be coupled for example to a triple glazing unit illustrated in Fig.1 b or in Fig.4. In the present embodiment, the outer and inner ventilation caps (110o, 11 Oi) together form a single cap (110) coupled respectively to the intermediate extension, the outer and inner glass panes, the first and second peripheral spacer (104, 105). In this manner, an outer and an inner ventilation gaps (not shown) are defined within the outer and inner ventilation caps. With the glazing in a vertical position, outlets (109) are provided above the inlets (108), both in the shape of horizontal slits.

[0065] Outer inlets are preferably configured to allow airflow from the exterior towards the intermediate extension’s outer face and / or heat transfer means affixed thereon.

[0066] Outer outlets are preferably configured to allow airflow from the intermediate extension’s outer face and / or heat transfer means affixed thereon towards the exterior.

[0067] Inner inlets are preferably configured to allow airflow from the interior towards the intermediate extension’s inner face and / or heat transfer means affixed thereon.

[0068] Inner outlets are preferably configured to allow airflow from the intermediate extension’s inner face and / or heat transfer means affixed thereon towards the interior.

[0069] In an embodiment of the present invention, the outer and / or inner ventilation means comprise one or more fans. Such fans, generally electrically operated, mayfurther increase heat transfer and / or increase convection.

[0070] In an embodiment of the present invention, the outer and / or inner ventilation means further comprises moveable shutters configured to at least partly open and close one or more of the outer and / or inner ventilation holes.

[0071] Moveable shutters allow for selecting whether the heat absorbed by the intermediate pane is vented towards the interior or the exterior, depending on thermal management needs of a building.

[0072] In an embodiment of the present invention, the ventilation means further comprises a selector configured to control the position of the movable shutters. The selector may be manually and / or automatically operable.

[0073] In an embodiment of the present invention the movable shutters comprise thermally sensitive means operable to control the position of the shutters and to place the intermediate extension in communication with the outside or inside air, responsive to temperature differentials in the outside or inside air and in said intermediate extension. The thermally sensitive means may have communication with the outside or inside air and with the intermediate extension, and actuating means drivingly connected to said shutters.

[0074] Depending on the temperature difference between the intermediate extension, the outside air, and the interior air, the shutters may be positioned to cover or uncover inner and / or outer ventilation holes. Thus airflow may be selectively established between the intermediate extension and the exterior or between the intermediate extension and the interior. Thus a part of the heat absorbed by the intermediate glass pane may be selectively directed towards the interior, for example if heating of the interior is required or towards the exterior for example if heating of the interior is to be reduced. In a traditional triple glazing unit, heat absorbed by the intermediate glass pane is reradiated in equal amounts towards the interior and the exterior via the inner glass pane and the outer glass pane respectively.

[0075] The glass substrates for the glass panes of the present invention can be chosen among clear, extra-clear or tinted glass sheets. The term “glass” is herein understoodto mean any type of glass or equivalent transparent material, such as a mineral glass or alternatively an organic glass. The mineral glasses used may be independently one or more known types of glass such as a soda-lime-silicate glass, an alumino-silicate glass, an alkali-free glass, a boro-silicate glass, crystalline and polycrystalline glasses. The glass substrate can be obtained by a floating process, a drawing process, a rolling process or any other process known to manufacture a glass substrate starting from a molten glass composition. Preferably, the glass substrate according to the invention is a substrate of soda-lime-silicate glass, aluminosilicate glass or borosilicate glass. More preferably and for reasons of lower production costs, the glass substrate according to the invention is a pane of soda-lime-silicate glass.

[0076] Advantageously, the expression substrate of soda-lime -silicate glass of the present invention is used in a broad sense and relates to any glass which comprises the following components in weight percentage, expressed with respect to the total weight of glass (Comp. A). More preferably, the glass composition (Comp. B) is a soda-lime-silicate-type glass with a base glass matrix of the composition comprising the following components in weight percentage, expressed with respect to the total weight of glass.

[0077] Other advantageous glass compositions for the glass substrates of the present invention, comprise the following components in weight percentage, expressed with respect to the total weight of glass:

[0078] In particular, examples of base glass matrixes for the composition according to the invention are described in published in PCT patent applications W02015 / 150207A1 , W02015 / 150403A1 , WO2016 / 091672 A1 , WO2016 / 169823A1 and WO2018 / 001965 A1.

[0079] According to certain embodiments of the invention, any of the glass substrates may have a composition comprising a total iron (expressed in terms of Fe2Os) content ranging from 0.002 to 0.06 weight%. A total iron (expressed in the form of Fe2Os) content of less than or equal to 0.06 weight% makes it possible to obtain a glass sheet with almost no visible coloration. Preferably, the composition comprises a total iron (expressed in the form of Fe2Os) content ranging from 0.002 to 0.04 weight%. More preferably, the composition comprises a total iron (expressed in the form of Fe2Os) content ranging from 0.002 to 0.020 weight%. Advantageously, for extra-clear glass, the composition comprises a total iron (expressed in the form of Fe2Os) content ranging from 0.002 to 0.015 weight% for the lowest visible light absorption.

[0080] In an embodiment of the present invention the outer and / or inner glass panes comprise substrates of soda-lime-silicate glass chosen from clear glass and extraclear glass depending on the aforesaid total iron content.

[0081] In an embodiment of the present invention, the intermediate glass pane comprises a tinted glass substrate. Tinted glass substrates are glass substrates having a light absorption higher than normal clear glass. In particular, the tinted glass is composed of a soda-lime -silicate glass comprising the aforesaid components and an added coloring agents giving rise to Planibel Bronze, Planibel Dark Blue, Planibel Dark Grey, Planibel Green, Planibel Grey, Planibel Linea Azzurra, Planibel Privablue soda-lime glass ranges commercialized by AGC Glass Europe.

[0082] According to an embodiment of the invention and for higher mechanical resistance, intermediate glass pane can be a pre-stressed glass. By pre-stressed glass, it means a heat strengthened glass, a thermally toughened safety glass, or a chemically strengthened glass.

[0083] Heat strengthened glass is heat treated using a method of controlled heating and cooling which places the outer glass surfaces under compression and the inner glass surface under tension. This heat treatment method delivers a glass with a bending strength greater than annealed glass but less than thermally toughened safety glass. Thermally toughened safety glass is heat treated using a method of controlled heating and cooling which puts the outer glass surface under compression and the inner glass surface under tension. Such stresses cause the glass, when impacted, to break into small granular particles instead of splintering into jagged shards. The granular particles are less likely to injure occupants or damage objects. The chemical strengthening of a glass article is a heat induced ion-exchange, involving replacement of smaller alkali sodium ions in the surface layer of glass by larger ions, for example alkali potassium ions. Increased surface compression stress occurs in the glass as the larger ions “wedge” into the small sites formerly occupied by the sodium ions. Such a chemical treatment is generally carried out by immerging the glass in an ionexchange molten bath containing one or more molten salt(s) of the larger ions, with a precise control of temperature and time. Aluminosilicate-type glass compositions, such as for example those from the products range DragonTrail® from Asahi Glass Co. or those from the products range Gorilla® from Coming Inc., are also known to be very efficient for chemical tempering.

[0084] The polymer interlayer that may be used in the present invention typically comprises a material selected from the group consisting ethylene vinyl acetate (EVA), polyisobutylene (PIB), polyvinyl butyral (PVB), polyurethane (PU), polyvinyl chlorides (PVC), polyesters, copolyesters, polyacetals, cyclo olefin polymers (COP), ionomer and / or an ultraviolet activated adhesive, and others known in the art of manufacturing glass laminates. Blended materials using any compatible combination of these materials can be suitable as well. According to an embodiment of the invention, the polymer interlayer comprises a thermoplastic material selected from the group consisting of ethylene vinyl acetate and polyvinyl butyral, more preferably polyvinyl butyral. The polymer interlayer is also designated as a “bonding interlayer” since the polymer interlayer and the glass pane form a bond that results in adhesion between the glass pane and the polymer interlayer.

[0085] According to an embodiment, the polymer interlayer to be used in an intermediate glass pane of the present invention may be a transparent or clear polymer interlayer. However, in order to enhance the energetical absorptions, it is preferred that the polymer interlayer is colored or patterned. In particular, the polymer interlayer may be a grey PVB.

[0086] Outer and inner glass panes may be assemblies of two glass substrates with a polymer interlayer, for example if required for safety or security purposes.

[0087] Typical thicknesses for polymer interlayers are 0.3 mm to 3.5 mm, preferably 0.75 mm to 1.75 mm. Traditional, commercially available polymer interlayers are polyvinyl butyral (PVB) layers of 0.38 mm and 0.76mm, 1 .52 mm, 2.28 m and 3.04mm. To achieve the desired thickness, one or more of those films can be used.

[0088] The present invention further concerns a partition defining an exterior space and an interior space, said partition comprising an opening being closed by a triple glazing unit according to any of the embodiments or combination of embodiments hereinabove, wherein the outer glass pane is facing the exterior space. Said partition may be a wall of a building for example.

[0089] The present invention further concerns the use of a triple glazing unit according to any of the embodiments or combination of embodiments hereinabove, wherein toclose the opening of a partition defining an exterior space and an interior space, wherein the outer glass pane is facing the exterior space, to transfer energy absorbed by the intermediate glass pane towards the exterior space and / or interior space, in particular by exposing the intermediate extension to air from the exterior and / or interior airspace respectively.

[0090] The present invention further concerns a process comprising providing a triple glazing unit according to any of the embodiments or combination of embodiments hereinabove in the opening of a partition defining an exterior space and an interior space, wherein the outer glass pane is facing the exterior space, exposing the glazing to sunlight, exposing the intermediate extension to air from the exterior and / or interior airspace respectively. Such a process may be used for thermally managing a building and / or for reducing the thermal stress of an intermediate glass pane in a triple glazing unit.

[0091] For thermally managing a building, the process may in particular further comprise determining temperatures in the outside air, the inside air, and the intermediate glass pane and positioning movable shutters to cover or uncover inner and / or outer ventilation holes. Thus airflow may be selectively established between the intermediate extension and the exterior or between the intermediate extension and the interior. Thus a part of the heat absorbed by the intermediate glass pane may be selectively directed towards the interior, for example if heating of the interior is required or towards the exterior for example if heating of the interior is to be reduced. In a traditional triple glazing unit, heat absorbed by the intermediate glass pane is reradiated in equal amounts towards the interior and the exterior via the inner glass pane and the outer glass pane respectively. Also, the thermal stress of an intermediate glass pane in a triple glazing unit may be reduced.Examples

[0092] A first triple glazing, example 1 , according to embodiments of the present invention was prepared. The outer glass pane was a 4mm thick clear soda-lime glass pane bearing a low emissivity functional coating on the face facing the first gap. The inner glass pane was a 4mm thick clear soda-lime glass pane bearing a low emissivityfunctional coating on the face facing the second gap. The intermediate glass pane was a 6mm thick bronze colored tinted soda-lime glass pane. The first and second gaps are filled with a gas comprising 90% Ar. The first gap is of 10mm thickness and the second gap is of 12mm thickness. Both functional coatings are thermal insulation coatings ‘iplus 1.T commercialized by AGC Glass Europe. A corresponding traditional triple glazing unit without heat transfer means and ventilation means on the intermediate extension, comparative example 1 , was also prepared.

[0093] A second triple glazing, example 2, according to embodiments of the present invention was prepared. The outer and inner glass panes were 4mm thick clear sodalime glass panes both bearing a lowE insulating coating iPlus 1.1 from AGC Glass Europe on their faces respectively in contact with the first gap and the second gap. The intermediate glass pane comprised two extra-clear, or low-iron, 4mm thick sodalime glass substrates joined by a 0.38mm thick grey PVB polymer interlayer. The first and second gaps are filled with a gas comprising 90% Ar. The first gap is of 10mm thickness and the second gap is of 12mm thickness. A corresponding traditional triple glazing unit without heat transfer means and ventilation means on the intermediate extension, comparative example 2, was also prepared.

[0094] A third triple glazing, example 3, according to embodiments of the present invention was prepared. The outer and inner glass panes were 4mm thick extra-clear, low-iron soda-lime glass panes, glass panes bearing no functional coatings The intermediate glass pane comprised two clear 4mm thick soda-lime glass substrates joined by a 0.72mm thick clear PVB polymer interlayer. The first and second gaps are filled with a gas comprising 90% Ar. The first gap is of 10mm thickness and the second gap is of 12mm thickness. The intermediate glass pane bears on the face facing the first gap a functional coating, the thermal insulation coating ‘iplus 1.1’ commercialized by AGC Glass Europe. The intermediate glass pane further bears on the face facing the second gap a functional coating, a solar control coating, ‘Stopray Vision 60 commercialized by AGC Glass Europe. A corresponding traditional triple glazing unit without heat transfer means and ventilation means on the intermediate extension, comparative example 3, was also prepared.

[0095] In the examples 1 to 3 and comparative examples 1 to 3, the intermediate extension extends by 10cm beyond the uppermost edge only of the outer and inner surfaces.

[0096] Table 1 below illustrates some opto-energetical properties of the examples. The properties are obtained in simulated working conditions where the triple glazing is positioned in a building with the outer glass pane facing the exterior space. The solar factor (SF) was calculated by simulation for examples 1 to 3 wherein for evaluation purposes all energy absorbed by the intermediate glass pane is estimated to be ventilated either towards the exterior, minimizing the solar factor, or towards the interior, maximizing the solar factor. Thus the solar factor can be varied as desired, depending on thermal management and needs of the building. The solar factor (SF) also designated as the solar heat gain coefficient measures how readily heat from direct solar energy flows through a glazing. Solar factor is the ratio between incident solar energy transmitted through a glazing, and the total solar energy received by the face of the outer glass pane facing the exterior space. SF is expressed as a percentage, the higher the value, the greater the solar energy transmitted through the glazing, so the more solar heat penetrates and the warmer the interior space is kept. The SF calculation is provided in standard norms such as norms EN410 or IS09050. Norm EN410 is typically used for building applications.

[0097] Good U-values and light transmittance (LT) are maintained.

[0098] The comparative examples 1 to 3 are limited to a fixed solar factor value.

[0099] Table 1

[0100] By selecting to vent heat from the sunlight absorbed by the intermediate glass pane outwards or inwards respectively, triple glazing units according to the invention can thus either reduce or increase their contribution to the heating of a building. For example, in winter it may contribute to the heating of a building and in summer overheating of the building can be reduced or avoided.

Claims

CLAIMSClaim 1 . A triple glazing unit comprising three glass panes, a. an outer glass pane (101) defining an outer surface bounded by an outer glass pane perimeter, b. an inner glass pane (103) defining an inner surface bounded by an inner glass pane perimeter, c. an intermediate glass pane (102) defining an intermediate surface bounded by an intermediate glass pane perimeter, the outer and intermediate glass panes being separated from one another by a first gap defined within a first peripheral spacer (104), the inner and intermediate glass panes being separated from one another by a second gap defined within a second peripheral spacer (105), wherein the first and second peripheral spacers (104, 105) follow the perimeter of the outer and inner glass panes respectively, the intermediate surface covers at least the entirety of the inner and outer surfaces and the intermediate surface is larger than at least one of the outer and inner surfaces and a part of the intermediate glass pane, the intermediate extension (102e), extends beyond at least one of the outer and inner surfaces, characterized in that the differences Aoand / or A between the energetic absorptance of the intermediate glass pane (102) AEint and the energetic absorptance of the inner AEi and / or outer glass pane AE0(101 , 103), where A0=AEint-AE0and Aj = AEint-AE, are greater than 10%, preferably greater than 15%, more preferably greater than 20%, even more preferably greater than 30%.Claim 2. A triple glazing unit according to claim 1 characterized in that the first and second gaps are hermetically separated from each other.Claim 3. A triple glazing unit according to any one preceding claim characterized in that the intermediate extension (102e) extends beyond one or more of the edges of the outer and / or inner surfaces.Claim 4. A triple glazing unit according to any one preceding claim characterized in that the intermediate extension (102e) extends at least beyond the uppermost edge of the outer and / or inner surfaces.Claim 5. A triple glazing according to any one preceding claim characterized in that the intermediate extension (102e) extends up to at least 5cm, 7cm, 8cm or even 10cm beyond at least one of the edges, for example the uppermost edge, of the outer and / or inner surfaces.Claim 6. A triple glazing unit according to any one preceding claim characterized in that the light transmittance of the triple glazing unit is at least 30%, preferably at least 40%, more preferably at least 50%.Claim 7. A triple glazing unit according to any one preceding claim characterized in that the intermediate glass pane (102) is selected from a single tinted glass substrate and an assembly of two glass substrates with a polymer interlayer.Claim 8. A triple glazing unit according to any one preceding claim characterized in that the intermediate glass pane (102) comprises a first functional coating on at least part of its outer face and / or a second functional coating on at least part of its inner face.Claim 9. A triple glazing according to any one preceding claim characterized in that the inner glass pane (103) comprises a third functional coating on a face oriented towards the intermediate glass pane and / or in that the outer glass pane (101) comprises a fourth functional coating on a face oriented towards the intermediate glass pane.Claim 10. A triple glazing unit according to any one preceding claim characterized in that the intermediate glass pane (102) is pre-stressed.Claim 11. A triple glazing unit according to any one preceding claim characterized in that intermediate extension (102e) has an outer face turned towards the outer glass pane (101) and / or an inner face, turned towards the inner glass pane (103) and in that it comprises heat transfer means (106, 107), affixed to at least one face of the intermediate extension (102e).Claim 12. A triple glazing unit according to any one preceding claim characterized in that it comprises ventilation means configured to allow air passage or air circulation to and / or from the intermediate extension’s outer and / or, separately, inner face.Claim 13. A triple glazing unit according to claim 12 characterized in that the ventilation means comprise a. outer ventilation means comprising an outer ventilation cap (110o), coupled to the intermediate extension (102e), the outer glass pane (101), the first peripheral spacer (104) and optionally to heat transfer means affixed to the intermediate extension’s outer face (106) and / or b. inner ventilation means comprising an inner ventilation cap (110i), coupled to the intermediate extension (102e), the inner glass pane (103), the second peripheral spacer (105) and optionally to heat transfer means affixed to the intermediate extension’s inner face (107).Claim 14. A triple glazing unit according claim 13 characterized in that the outer and / or inner ventilation caps comprise respectively at least one outer and / or inner ventilation hole or a plurality of outer and inner ventilation holes.Claim 15. A triple glazing unit according to claim 14 characterized in that the outer and / or inner ventilation means further comprises moveable shutters configured to at least partly open and close one or more of the outer and / or inner ventilation holes.Claim 16. Partition defining an exterior space and an interior space, said partition comprising an opening being closed by a triple glazing unit according to any one preceding claim, wherein the outer glass pane is facing the exterior space.Claim 17. Use of a triple glazing unit according to any one of claims 1 to 15 to close the opening of a partition defining an exterior space and an interior space, wherein the outer glass pane is facing the exterior space, to transfer energy absorbed by the intermediate glass pane towards the exterior space and / or interior space, in particular by exposing the intermediate extension to air from the exterior and / or interior airspace respectively.Claim 18. Process comprising providing a triple glazing unit according to any one of claims 1 to 15 in the opening of a partition defining an exterior space and an interior space, wherein the outer glass pane is facing the exterior space, exposing the glazing to sunlight, exposing the intermediate extension to air from the exterior and / or interior space.

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