LAMINATED GLAZING WITH COLOURED REFLECTION AND HIGH SOLAR TRANSMITTANCE SUITABLE FOR SOLAR ENERGY SYSTEMS

Abstract

A laminated and etched glazing unit having a substrate and a multi-layered interference filter each delimited by two main faces; the incident medium having a refractive index n.sub.inc=1, the substrate having a refractive index n.sub.substrate defined as: 1.45n.sub.substrate1.6 at 550 nm, and the exit medium being defined as follows 1.45n.sub.exit1.6 at 550 nm; and wherein the following requirements are met: The saturation of the colour is higher than 8 at near-normal angle of reflection, except for grey and brown; the visible reflectance is higher than 4%; the variation of the dominant wavelength .sub.MD of the dominant colour M.sub.D of the reflection is smaller than 15 nm for .sub.r<60; and the total hemispherical solar transmittance is above 80%.

Claims

1-24. (canceled)

25. A laminated glazing unit for architectural integration of solar energy systems comprising a substrate delimited by two main faces and a multi-layered interference filter also delimited by two main faces and in contact on one main face with said substrate and on the other main face with a laminating polymer; said substrate being in contact with an incident medium having a refractive index n.sub.inc=1 and having a refractive index nine substrate defined as follows: 1.45n.sub.substrate1.6 at 550 nm and; said laminating polymer being the exit medium whose refractive index is defined as follows 1.45nexit1.6 at 550 nm; and wherein said unit is designed in such a way that the following requirements are met: 1a) The saturation of the colour, given by C*.sub.ab={square root over ((a*).sup.2+(b*).sup.2)}, according to the CIE colour coordinates L*, a* and b* under daylight illumination CIE-D65 is higher than 8 at normal angle of reflection, except for grey and brown. 1b) The visible reflectance at near-normal angle of reflection R.sub.vis is higher than 4%. 1c) The variation of the dominant wavelength .sub.MD of the dominant colour MD of the reflection with varying angle of reflection r is smaller than 15 nm for r<60. 1d) The total hemispherical solar transmittance at normal incidence is above 80%.

26. The glazing unit according to claim 25 comprising a light-diffusing rough outer surface on the other main face of the substrate, the light-diffusing rough outer surface being obtained by chemical treatment.

27. The glazing unit according to claim 25 comprising an acidic etched anti-reflective outer surface on the other main face of the substrate to enhance the optical properties of the system: the solar transmittance of a light beam at normal incidence is approx. 3% higher for the etched surface than for an untreated surface.

28. The glazing unit according to claim 25 further comprising an anti-reflective coating applied on the back-side of the laminated glazing in order to enhance the optical properties of the system for solar thermal applications: the solar transmittance of a light beam at normal incidence is approx. 3% higher for the surface on which the anti-reflective coating is applied than for an untreated surface.

29. The glazing unit according to claim 25, wherein the substrate comprises solar roll glass, an extra-white float glass with an iron content <120 ppm or a polymeric material characterised by a solar transmittance higher than 90%.

30. The glazing unit according to claim 25, wherein the substrate includes a solar roll glass and the solar roll glass surfaces are either flat or textured.

31. The glazing unit according to claim 25, wherein the laminating polymer comprises an elastomer cross-linking polymer, a thermoplastic product, or an ionoplastic polymer to join glass or polymeric panes together by lamination and the solar transmittance of the unit is higher than 92% for a polymer thickness of 0.4-0.5 mm.

32. The glazing unit according to claim 25, wherein said multi-layered interference filter is a multilayer interferential stack of up to 9 layers, up to 400 nm physical thickness dielectric layers with low absorption expressed by the extinction coefficient k0.2 for wavelengths with 450 nm2500 nm.

33. The glazing unit according to claim 25, wherein the substrate is comprised of glass or a polymer, and said interference filter has a green coloured reflection and is deposited on the glass or polymer substrate with 1.45n.sub.substrate1.6 at 550 nm and composed by 3 sub-layers based on low refractive index material L with 1.4nL2.2 at 550 nm and high refractive index material H with 1.8n.sub.H2.5 at 550 nm; the general design being: incident medium air//substrate//3012 nm of H/2512 nm of L/32012 nm of H///exit medium polymer, wherein thickness are physical thicknesses.

34. The glazing unit according to claim 25, wherein the substrate is comprised of glass or a polymer, and said interference filter has a green coloured reflection and is deposited on the glass or polymer substrate with 1.45n.sub.substrate1.6 at 550 nm and composed by 5 sub-layers based on low refractive index material L with 1.4n.sub.L2.2 at 550 nm and high refractive index material H with 1.8n.sub.H2.5 at 550 nm; the general design being: incident medium air//substrate//18512 nm of H/2512 nm of L/3512 nm of H/3512 nm of L/13012 nm of H//exit medium polymer, wherein thickness are physical thicknesses.

35. The glazing unit according to claim 25, wherein the substrate is comprised of glass or a polymer, and said interference filter has a green coloured reflection and is deposited on the glass or polymer substrate with 1.45n.sub.substrate1.6 at 550 nm and composed by 7 sub-layers based on low refractive index material L with 1.4n.sub.L2.2 at 550 nm and high refractive index material H with 1.8n.sub.H2.5 at 550 nm; the general design being: incident medium air//substrate//16012 nm of H/13012 nm of L/6512 nm of H/2512 nm of L/7012 nm of H/16012 nm of L/10012 nm of H//exit medium polymer, wherein thickness are physical thicknesses.

36. The glazing unit according to claim 25, wherein the substrate is comprised of glass or a polymer, and said interference filter provides a blue coloured reflection and is deposited on the glass or polymer substrate with 1.45n.sub.substrate1.6 at 550 nm and composed by 3 sub-layers based on low refractive index material L with 1.4n.sub.L1.8 at 550 nm and high refractive index material H with 1.8n.sub.H2.5 at 550 nm; the multilayer design corresponding hereby to: incident medium air//substrate/4512 nm of H/7012 nm of L/4512 nm of H//exit medium polymer, wherein thickness are physical thicknesses.

37. The glazing unit according to claim 25, wherein the substrate is comprised of glass or a polymer, and said interference filter provides a yellow-green coloured reflection and is deposited on the glass or polymer substrate with 1.45n.sub.substrate1.6 at 550 nm and composed by 5 sub-layers based on low refractive index material L with 1.65n.sub.L2.1 at 550 nm and high refractive index material H with 1.8n.sub.H2.5 at 550 nm; the multilayer design corresponding hereby to: incident medium air//substrate/17512 nm of H/8512 nm of L/5012 nm of H/2512 nm of L/30012 nm of H//exit medium polymer, wherein thickness are physical thicknesses.

38. The glazing unit according to claim 25, wherein the substrate is comprised of glass or a polymer, and said interference filter provides a yellowish-orange coloured reflection and is deposited on the glass or polymer substrate with 1.45n.sub.substrate1.6 at 550 nm and composed by 7 sub-layers based on low refractive index material L with 1.4n.sub.L1.8 at 550 nm and high refractive index material H with 1.8n.sub.H2.5 at 550 nm; the multilayer design corresponding hereby to: incident medium air//substrate/12012 nm of H/12012 nm of L/9512 nm of H/9012 nm of L/9012 nm of H/9512 nm of L/10012 nm of H//exit medium polymer, wherein thickness are physical thicknesses.

39. The glazing unit according to claim 25, wherein the substrate is comprised of glass or a polymer, and said interference filter provides a grey coloured reflection deposited on the glass or polymer substrate with 1.45n.sub.substrate1.6 at 550 nm and composed by 2 sub-layers based on low refractive index material L with 1.4n.sub.L1.8 at 550 nm and high refractive index material H with 1.8n.sub.H2.5 at 550 nm; the multilayer design corresponding hereby to: incident medium air//substrate//4015 nm of H/7530 nm of L//exit medium polymer, wherein thickness are physical thicknesses.

40. The glazing unit according to claim 25, wherein the substrate is comprised of glass or a polymer, and said interference filter provides a brown coloured reflection and is deposited on the glass or polymer substrate with 1.45n.sub.substrate1.6 at 550 nm and composed by 4 sub-layers based on low refractive index material L with 1.65n.sub.L2.1 at 550 nm and high refractive index material H with 1.8n.sub.H2.5 at 550 nm; the multilayer design corresponding hereby to:incident medium air//substrate//5012 nm of H/9012 nm of L/6512 nm of H/5512 nm of L//exit medium polymer, wherein thickness are physical thicknesses.

41. The glazing unit according to claim 25, further comprising one or more heat treated glass pane(s) for security in facade applications.

42. A solar energy system comprising a laminated glazing unit according to claim 25.

43. The solar energy system according to claim 42 comprising a thermal collector and wherein the laminated glazing unit is directly glued to the solar thermal collector.

44. The solar energy system according to claim 43 wherein the laminated glazing unit is larger than a frame of the thermal collector.

45. The solar energy system according to claim 42 comprising a photovoltaic system with an active system fully integrated in the laminated glazing unit.

46. A solar roof or building facade comprising the solar energy system according to claim 42.

47. The solar roof or building facade according to claim 46 wherein the solar energy system is suspended by fixations attached to the laminated glazing unit.

48. The solar roof or building facade according to claim 46 including a plurality of laminating glazing units with an overlapping of the laminated glazing units.

49. The glazing unit according to claim 29, wherein the polymeric material is PET, PEN, PFA, FEP, ETFE, or PTFE.

50. The glazing unit according to claim 31, wherein the elastomer cross-linking polymer is EVA, or the thermoplastic product is PVB.

51. The solar energy system according to claim 45, wherein the photovoltaic system with an active system includes silicon cells, photovoltaic thin films, contacts or a back reflector.

Description

LIST OF FIGURE CAPTIONS

[0094] FIG. 1:

[0095] Angular dependency of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 1.

[0096] FIG. 2:

[0097] Reflectance curves of the coating design given in Example 1 for various angles of reflection (from 0 to 85).

[0098] FIG. 3:

[0099] Schematic drawings of possible configurations of coloured laminated glazing for thermal and PVT applications. The coloured coating can be deposited (a) on the back side of the outer glass, (b) on one side of a polymeric film which is encapsulated between two glass panes, (c) on the front side of the inner glass.

[0100] FIG. 4:

[0101] Schematic drawings of possible configurations of coloured laminated glazing for PV applications. The coloured coating can be deposited (a) on the back side of the outer glass, (b) on one side of a polymeric film which is encapsulated between two glass panes, (c) on the front side of the inner glass. Here the technical parts of the PV device are fully integrated into the laminated glazing.

[0102] FIG. 5:

[0103] 1988 C.I.E. normalised photopic luminous efficiency function delimiting the part of the solar spectrum which is visible for the human eye and reflectance curve at normal incidence (angle of vision of 0) of a yellow-green coating (.sub.max=570 nm) presenting a single reflection peak.

[0104] FIG. 6:

[0105] 1988 C.I.E. normalised photopic luminous efficiency function delimiting the part of the solar spectrum which is visible for the human eye and reflectance curve at normal incidence (angle of vision of 0) of a green coating (.sub.D=500 nm) presenting three reflection peaks in the visible part of the solar spectrum (bulk part of the curve).

[0106] FIG. 7: [0107] (a) Reflectance curves of a yellow-green coating for various angles of reflection (from 0 to 85). The reflection peak situated in the visible part of the spectrum shifts to smaller wavelengths: .sub.max varies from .sub.max 0=570 nm to .sub.max 60=500 nm leading to a colour change of the coating from yellow-green to green. [0108] (b) Same representation for a green coating design presenting three reflection peaks in the visible part of the solar spectrum.

[0109] FIG. 8: [0110] (a) Graphical representation of a fictive reflectance curve composed by two reflection peaks in the visible part of the solar spectrum. .sub.1, C.sub.1 and .sub.2, C.sub.2 are the wavelengths and colours of the reflectance peaks at low viewing angle. .sub.1, C.sub.1 and .sub.2, C.sub.2 are the corresponding wavelengths and colours at higher angle of observation. The dominant colour M.sub.D of the coating is situated at .sub.D comprised between .sub.1 and .sub.2, its position depending on the relative intensity of both reflection peaks. [0111] (b) Principle of colour stability represented on the 1931 C.I.E. chromaticity diagram. M is the resultant colour of a coating characterised by 2 reflection peaks, in the visible part of the solar spectrum, defined by C.sub.1 and C.sub.2 at low angle of vision. C.sub.1 and C.sub.2 are the corresponding colours for higher angle of vision. M.sub.D is the dominant colour of M.

[0112] FIG. 9: [0113] (a) Graphical representation of a fictive reflectance curve composed by three reflection peaks in the visible part of the solar spectrum. .sub.1, C.sub.1, .sub.2, C.sub.2 and .sub.3, C.sub.3 are the wavelengths and colours of the reflectance peaks at low viewing angle. .sub.1, C.sub.1, .sub.2, C.sub.2 and .sub.3, C.sub.3 are the corresponding wavelengths and colours at higher angle of observation. The dominant colour M.sub.D of the coating is situated at .sub.D whose position depends on the relative intensity of all reflection peaks. [0114] (b) Principle of colour stability represented on the 1931 C.I.E. chromaticity diagram. M is the resultant colour of a coating characterised by 3 reflection peaks, in the visible part of the solar spectrum, defined by C.sub.1, C.sub.2 and C.sub.3 at low angle of vision. C.sub.1, C.sub.2 and C.sub.3 are the corresponding colours for higher angle of vision. M.sub.D is the dominant colour of M.

[0115] FIG. 10:

[0116] Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 2.

[0117] FIG. 11:

[0118] Reflectance curves of the coating design given in Example 2 for various angles of reflection (from 0 to 85).

[0119] FIG. 12:

[0120] Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 3.

[0121] FIG. 13:

[0122] Reflectance curves of the coating design given in Example 3 for various angles of reflection (from 0 to 85).

[0123] FIG. 14:

[0124] Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 4.

[0125] FIG. 15:

[0126] Reflectance curves of the coating design given in Example 4 for various angles of reflection (from 0 to 85).

[0127] FIG. 16:

[0128] Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 5.

[0129] FIG. 17:

[0130] Reflectance curves of the coating design given in Example 5 for various angles of reflection (from 0 to 85).

[0131] FIG. 18:

[0132] Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 6.

[0133] FIG. 19:

[0134] Reflectance curves of the coating design given in Example 6 for various angles of reflection (from 0 to 85).

[0135] FIG. 20:

[0136] Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 7.

[0137] FIG. 21:

[0138] Reflectance curves of the coating design given in Example 7 for various angles of reflection (from 0 to 85).

[0139] FIG. 22:

[0140] Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 8.

[0141] FIG. 23:

[0142] Reflectance curves of the coating design given in Example 8 for various angles of reflection (from 0 to 85).

[0143] FIG. 24:

[0144] Angular stability of 1931 CIE (x, y) colour coordinates under CIE-D65 illuminant of the coloured design given in Example 9.

[0145] FIG. 25:

[0146] Reflectance curves of the coating design given in Example 9 for various angles of reflection (from 0 to 85).

[0147] FIG. 26:

[0148] Normal hemispherical transmittance measurements of a glass etched by solution 1 (ABF/IPA/H.sub.2O=30/10/6015 min etch time), a glass etched by solution 2 (ABF/sucrose/H.sub.2O=18/18/6415 min etch time) and an untreated glass. The normal hemispherical transmittance is around 95% for both etched glasses and around 92% for the untreated glass.

[0149] FIG. 27:

[0150] SEM pictures of glass surfaces structured by ABF-based etching solutions:

[0151] (a) ABF/IPA/H.sub.2O=30/10/6015 min etch time

[0152] (b) ABF/sucrose/H.sub.2O=18/18/6415 min etch time.

[0153] FIG. 28:

[0154] Possible variations for the mounting of thermal or PVT solar systems glued behind a coloured laminated glazing: (a) example of roof installation with glazing overlap, (b) example of installation for residential ventilated facade, (c) example of adaptation to large buildings with glass facades.

[0155] FIG. 29:

[0156] Illustration of the reflection angle .sub.r, incidence angle .sub.l and transmission angle .sub.t.

EXAMPLES OF COATING DESIGNS

Example 1

[0157] air//136 nm of L/222 nm of H//glass//222 nm of H/136 nm of L//air

[0158] with n.sub.H=1.54 and n.sub.L=1.8

Example 2

[0159] air//glass//30 nm of H/25 nm of L/320 nm of H//polymer

[0160] with n.sub.H=2.4 and n.sub.L=1.65

Example 3

[0161] air//glass//18512 nm of H/2512 nm of L/3512 nm of H/3512 nm of L/13012 nm of H//polymer

[0162] with n.sub.H=2.4 and n.sub.L=2.0

Example 4

[0163] air//glass//16012 nm of H/13012 nm of L/6512 nm of H/2512 nm of L/7012 nm of H/16012 nm of L/10012 nm of H//polymer

[0164] with n.sub.H=2.2 and n.sub.L=2.0

Example 5

[0165] air//glass//4512 nm of H/7012 nm of L/4512 nm of H//polymer

[0166] with n.sub.H=2.0 and n.sub.L=1.65

Example 6

[0167] air//glass//17512 nm of H/8512 nm of L/5012 nm of H/2512 nm of L/30012 nm of H//polymer

[0168] with n.sub.H=2.4 and n.sub.L=2.0

Example 7

[0169] air//glass//12012 nm of H/12012 nm of L/9512 nm of H/9012 nm of L/9012 nm of H/9512 nm of L/10012 nm of H//polymer

[0170] with n.sub.H=2.0 and n.sub.L=1.65

Example 8

[0171] air//glass//4012 nm of H/7512 nm of L//polymer

[0172] with n.sub.H=2.4 and n.sub.L=1.65

Example 9

[0173] air//glass//5012 nm of H/9012 nm of L/6512 nm of H/5512 nm of L//polymer

[0174] with n.sub.H=2.4 and n.sub.L=2.0