Multi-pane window

Abstract

The invention relates to a window having a first pane (2; 3) and a second pane (3; 20) spaced apart therefrom, wherein the first pane (2) has a first side (4) facing the second pane (3) and the second pane (3) has a second side (5) facing the first pane (2), wherein a cavity (6; 22) is present between the two mutually facing sides (4, 5), which cavity is closed by means of an edge composite (7) and is filled with a gaseous medium (5), wherein the two panes (2, 3; 20) are transparent for radiation from the visible wavelength range and radiation from the infrared range, wherein the edge composite (7; 21) has a photovoltaic cell (8; 25) which converts IR radiation at a predefined wavelength from the infrared range into electrical energy, wherein the first pane (2) has a first hologram (10) and the second pane (3) has a second hologram (11), wherein the two holograms (10, 11) are designed such that the IR radiation (L1) which has the predefined wavelength and is incident on the first pane (2) at a predefined first angle of incidence (α1) is first deflected at one of the two holograms (10, 11) to the other hologram (10, 11) in such a way that the deflected IR radiation (L2) is incident on the other of the two holograms (10, 11) at a second angle of incidence (α3) which is greater than the first angle of incidence (α1) and is deflected from said hologram in such a way that it is incident in the cavity (6) at a first angle of reflection (β3) which is greater than the second angle of incidence (α3), and propagates in the cavity to the photovoltaic cell (8; 25).

Description

[0001] Carl Zeiss Jena GmbH

[0002] Windows with multiple panes

[0003] The present invention relates to a window with multiple panes.

[0004] There is a growing need to utilize windows, which are installed in large numbers in buildings, for generating electrical energy using photovoltaic cells. It is known to incorporate, for example, a holographic optical element into the glass material of the window pane. This element deflects a portion of the visible light, a portion of the UV radiation, and / or a portion of the IR radiation by diffraction, directing it within the glass to a photovoltaic cell positioned at the glass's edge. Furthermore, it is known to couple desired radiation into the glass pane using an input hologram. Within the glass pane, this radiation is guided by total internal reflection to the point where either a photovoltaic cell is located or an output coupling element is positioned, directing the radiation via the output coupling element to a photovoltaic cell.

[0005] A disadvantage of all these solutions is that the guidance takes place within the glass material, which has high absorption, resulting in extremely low efficiency in generating electrical energy. If visible light is used, this leads to a color shift in the transmitted light, which is undesirable. Furthermore, it is difficult to position the photovoltaic cell on the edge of the glass pane, as the edges typically have special shapes to improve stability or meet other boundary conditions. These shapes are detrimental to the coupling of the radiation to the photovoltaic cell.

[0006] Based on this, the object of the invention is to provide a window in which electrical energy can be generated more efficiently from the solar radiation striking the window.

[0007] The invention is defined in claim 1. Advantageous embodiments are specified in the dependent claims.

[0008] The window according to the invention comprises a first pane and a spaced-apart second pane, wherein the first pane has a first side facing the second pane and the second pane has a second side facing the first pane. A cavity exists between the facing sides, which is sealed by means of an edge seal (preferably hermetically or gas- and moisture-tight) and filled with a gaseous medium. The two panes are transparent to radiation in the visible wavelength range (400 nm - 780 nm) and to radiation in the infrared range (greater than 780 nm up to 2500 nm). The edge seal includes a photovoltaic cell (or a solar cell or a solar sensor) that converts IR radiation with a predetermined wavelength from the infrared range into electrical energy (preferably current).The first disk has a first hologram and the second disk has a second hologram, the two holograms being designed such that the IR radiation, which has a predetermined wavelength and which strikes the first disk at a predetermined first angle of incidence (preferably from the range of 0° - 30°, including the limits), undergoes a first deflection at one of the two holograms to the other of the two holograms such that the deflected IR radiation strikes the other of the two holograms at a second angle of incidence greater than the first angle of incidence and is deflected by it so that it enters the cavity at a first angle of reflection greater than the second angle of incidence and propagates within it to the photovoltaic cell.

[0009] According to the invention, the cavity is thus used as a waveguide, minimizing absorption losses. This enables efficient energy harvesting.

[0010] The IR radiation can propagate in the cavity in such a way that, after the second deflection at the two holograms, it is guided either directly, by exactly one Fresnel reflection on this opposite side, by exactly one Fresnel reflection on each of the two sides, or by several Fresnel reflections on the facing sides of the two disks to the photovoltaic cell.

[0011] In particular, the first side of the first disk can define the cavity, and / or the second side of the second disk can define the cavity. This can be achieved, for example, by embedding (or burying) the first hologram in the first disk and / or by embedding (or burying) the second hologram in the second disk. Alternatively, the first hologram can be arranged within the first disk, and / or the second hologram can be arranged within the second disk. Thus, it is possible to guide the coupled IR radiation to the photovoltaic cell via at least one Fresnel reflection.

[0012] Thus, depending on the coupling point of the IR radiation on the first pane, light guidance to the photovoltaic cell can always be effectively achieved. The photovoltaic cell generates electricity, which can be stored in a rechargeable battery. This provides a grid-independent, self-sufficient energy source within the window. This can be used to power electrical actuators in or on the window. Possible actuators could, for example, open or close the window, raise or lower a blind or shades, and / or change the transmission of an electrochromic coating by applying a potential. The rechargeable battery can be located in or on the window (e.g., attached) or positioned at a distance from the window. Preferably, the rechargeable battery is designed to be replaceable.

[0013] The gaseous medium could be, for example, air or a noble gas (such as argon, krypton or xenon).

[0014] The two holograms are preferably transparent to radiation in the visible wavelength range. This means, in particular, that the holograms do not deflect or reflect any radiation from the visible wavelength range. The holograms only deflect or reflect IR radiation with the predetermined wavelength. Thus, the optical impression of the window for a user is the same as that of a conventional window pane.

[0015] Preferably, the two holograms cause the deflection by reflection. In this case, the IR radiation striking the first disk can initially be transmitted through the first hologram before being reflected by the second hologram back to the first hologram and then reflected again by the first hologram. At least one of the holograms can be a volume hologram.

[0016] The two panes could particularly be glass panes.

[0017] The second angle of incidence can be equal to the Brewster angle for a Fresnel reflection at the corresponding disk or deviate from it by no more than 5°.

[0018] The first angle of incidence can be greater than or equal to 80° and less than 90°.

[0019] The window may have an imaging optic (e.g. a cylindrical lens) that focuses the propagating IR radiation onto the photovoltaic cell.

[0020] Furthermore, the window may have a third pane, which is provided in relation to the first or second pane, wherein between the two facing sides of the first or second pane and the third pane there is a further cavity which is sealed by means of a further edge seal (preferably hermetically or gas- and moisture-tight) and which is filled with a gaseous medium.

[0021] In this case, triple glazing would be used. Of course, quadruple glazing or even a higher number of panes is also possible.

[0022] The second cavity can also be used as a waveguide for IR radiation, if desired. In this case, appropriate holograms simply need to be provided in the first and second disks, as well as the third disk, which function in the same way as the first and second holograms to couple IR radiation into the cavity. These additional holograms can be designed for IR radiation with a different angle of incidence and / or a different wavelength (or wavelengths). Naturally, another photovoltaic cell is provided in this case to convert the IR radiation striking it into electrical energy.

[0023] The holograms can be formed at an interface of the respective disk. For example, they can be formed in a film applied to the interface. However, it is also possible for the holograms to be arranged within the respective disk, or embedded or buried within it. This is preferably achieved by making the disks multi-part (for example, two-part) and arranging the holograms between the two disk parts.

[0024] The corresponding electrical connections of the photovoltaic cell(s) can, for example, be routed through the corresponding edge seal.

[0025] The window according to the invention can be used as a conventional window, as part of a door, or as a pane in buildings, vehicles, or in other ways. The window according to the invention can also be referred to as multiple glazing (for example, double glazing, triple glazing, quadruple glazing, etc.).

[0026] For photovoltaic cells, a semiconductor material can be used in particular. Examples include monocrystalline silicon or CIGS (copper indium gallium diselenide).

[0027] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations given, but also in other combinations or on their own, without leaving the scope of the present invention.

[0028] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings, which also disclose essential features of the invention. These exemplary embodiments serve only for illustration and are not to be interpreted as limiting. For example, a description of an exemplary embodiment with a plurality of elements or components is not to be interpreted as meaning that all of these elements or components are necessary for implementation. Rather, other exemplary embodiments may also contain alternative elements and components, fewer elements or components, or additional elements or components. Elements or components of different exemplary embodiments may be combined with one another unless otherwise specified. Modifications and variations described for one of the exemplary embodiments may also be applicable to other exemplary embodiments.To avoid repetition, identical or corresponding elements in different figures are designated with the same reference symbols and are not explained multiple times. The figures show:

[0029] Fig. 1 shows a schematic view of a first embodiment of the window according to the invention;

[0030] Fig. 2 is an enlarged view of detail D from Fig. 1;

[0031] Fig. 3 a schematic sectional view of the window of Fig. 1 with a different point of impact of the light beam L1 ';

[0032] Fig. 4 a diagram to illustrate the Fresnel reflection at the first and second disk 2, 3;

[0033] Fig. 5 shows a representation of the radiation flux of sunlight through a window 1, in which no holograms 10 and 11 are provided;

[0034] Fig. 6 is a representation according to Fig. 5, wherein the window 1 has the holograms 10 and 11;

[0035] Fig. 7 shows a representation of the radiation flux on the photovoltaic cell 8; Fig. 8 shows a representation according to Fig. 1 of a further embodiment of the window according to the invention and

[0036] Fig. 9 is a schematic representation according to Fig. 1 of a further embodiment of the window according to the invention.

[0037] In the embodiment shown in Figure 1, the window 1 according to the invention comprises a first pane 2 and a second pane 3 spaced apart from it, wherein the first pane 2 has a first side 4 facing the second pane 3 and the second pane 3 has a second side 5 facing the first pane 2. A cavity 6 is thus formed between the two facing sides 4, 5, which is sealed gas- and moisture-tight, i.e., hermetically, by means of an edge seal 7. A gaseous medium, such as air or a noble gas (for example, argon, krypton, or xenon), is filled into the cavity 6.

[0038] The two panes 2 and 3, which can be glass panes, for example, are transparent to radiation in the visible wavelength range and to radiation in the infrared range. The edge seal 7 is designed in particular to hold the two panes 2 and 3 together at a predetermined distance to ensure the cavity 6 and to prevent the gaseous medium from escaping from the cavity 6 and ambient air and moisture from penetrating the cavity 6.

[0039] In the embodiment shown in Figure 1, a photovoltaic cell 8 is arranged within the cavity 6 on the lower part of the edge seal 7, as shown in Figure 1. This can be a single photovoltaic cell or several photovoltaic cells 8. In the embodiment described here, the photovoltaic cell(s) is / are preferably arranged along the entire extent of the window 1 perpendicular to the plane of the drawing. The photovoltaic cell(s) 8 are specifically designed to convert IR radiation with one or more predetermined wavelengths from the infrared range into electrical energy. In the embodiment described here, the predetermined wavelengths of 850 nm and 1250 nm are considered.

[0040] As can be further seen in Figure 1, the first disk 2 has a first hologram 10 and the second disk 3 has a second hologram 11. The two holograms 10 and 11 are designed such that they deflect infrared radiation, which strikes the first disk 2 at a predetermined angle of incidence ai from the range of 0° to 30°, twice so that it then propagates in the cavity 6 to the photovoltaic cell 8. After the second deflection by the two holograms 10, 11, no further Fresnel reflection can occur on either side 4, 5, exactly one Fresnel reflection can occur on either side 4, 5, exactly one Fresnel reflection can occur on each side 4, 5, or more than two Fresnel reflections can occur on either side 4, 5 in total, until the IR radiation reaches the photovoltaic cell 8.In the embodiment shown in Figure 1, after the two deflections at the two holograms 10, 11, exactly one Fresnel reflection occurs on the second side 5 and exactly one Fresnel reflection occurs on the first side 4.

[0041] As can be seen from Figure 1 in conjunction with Figure 2, the system assumes a sunlight ray L1 striking the side 12 of the first disk 2 facing away from the second disk 3 at an angle of incidence ai of 15°, which is transmitted through the first disk 2 and the first hologram 10 (except for the refraction caused by the different refractive indices) unaffected and exits the first side 4 at the same angle of 15° (angle of reflection ßi) and strikes the second side 5 at this angle (angle of incidence az) of 15° and enters the second disk 3 and there strikes the second hologram 11.The second hologram 11 is now designed for the angle of incidence of 15° with respect to the second side 5 (all specified angles of incidence and reflection are each with respect to air) and the wavelengths of 850 nm and 1250 nm such that this IR radiation L2 is reflected back to the first disk 2 in such a way that it exits the second disk 3 at an angle of reflection β2 of 56° and thus hits the first side 4 of the first disk 2 with an angle of incidence β3 of 56°, enters the first disk 2 and hits the first hologram 10 there. The first hologram 10 is now designed for IR radiation L2 with wavelengths of 850 nm and 1250 nm, which hits the first side 4 at the aforementioned angle of incidence 03, such that it reflects this back to the second side 5 in such a way that it exits the first disk 2 via the first side 4 with an angle of reflection ßs of 85°.At this angle, the IR radiation L2 then strikes the second side 3 and is reflected by Fresnel reflection towards the first side 4, where another Fresnel reflection takes place, so that the IR radiation L2 finally strikes the photovoltaic cell 8, as shown in Figure 1. Thus, the cavity 6 is used as a waveguide for the IR radiation L2, which is to strike the photovoltaic cell 8.

[0042] Other wavelengths of the incident sunlight L1 are not reflected by the two holograms 10, 11, but transmit through them unaffected, so that they emerge from the second disk 3 as radiation L3 via a side 13 of the second disk 3 facing away from the first disk 2.

[0043] Thus, a portion of the normally unwanted IR radiation is deflected by means of the holograms 10, 11 to the photovoltaic cell 8, so that the window 1 can also be referred to as a holographic solar window 1. Figure 3 shows, in the same way as Figure 1, the case in which, due to the position of the solar radiation L1' striking side 12 of the first disk 2, the deflected IR radiation L2', after being deflected by the two holograms 10, 11, strikes the photovoltaic cell 8 directly.

[0044] In the first deflection using the second hologram 11, the angle of reflection β2, and thus also the angle of incidence θ3, is chosen such that it preferably corresponds to the Brewster angle BW, at which the Fresnel reflection for p-polarized radiation becomes zero, as shown in the diagram in Figure 4. In Figure 4, the angle of incidence in [°] is plotted along the abscissa and the reflectivity from 0 to 1 along the ordinate, where 0 represents no reflection and 1 represents 100% reflection. Curve K1 shows the reflection of p-polarized radiation for the known window glass used (N-K5) at a wavelength of 1000 nm, curve K2 shows the reflection of s-polarized radiation under these conditions, curve K3 shows the corresponding transmission for p-polarized radiation under these conditions, and curve K4 shows the corresponding transmission for s-polarized radiation under these conditions.

[0045] The third angle of incidence ßs of 85° is chosen so that the highest possible Fresnel reflection HR occurs, which can again be seen in the illustration of Figure 4.

[0046] The reason why the angle of reflection β2 and thus also the angle of incidence θ3 are chosen to preferably correspond to the Brewster angle BW is, among other things, as follows. The Fresnel equations quantitatively describe the reflection and transmission of a plane electromagnetic wave at a plane interface. Therefore, such a reflection is also frequently referred to as Fresnel reflection. If, for example, it is desired that light should transmit through a surface, the Fresnel reflection that occurs is an undesirable loss. In order to direct more light to the hologram 10, instead of reflecting the light at the first and / or second side 4, 5 through Fresnel reflection and thus propagating it in the disk 2 and / or 3, the Brewster angle is advantageous in order to transmit the p-polarized radiation completely.

[0047] Figure 5 shows the radiative flux of sunlight (specifically, sunlight filtered through the atmosphere at sea level) through a window 1 without the two holograms 10 and 11 as a function of wavelength for an angle of incidence of 15°, with the wavelength in [pm] plotted along the abscissa and the flux in [watts] along the ordinate. Figure 6 shows, in the same representation, the radiative flux of solar radiation through window 1, which now includes the two holograms 10 and 11.

[0048] Figure 7 shows the radiation flux reaching the photovoltaic cell 8 due to the holograms. The illustrations in Figures 5 and 6 assume a total of 100 watts of sunlight, with the two holograms 10 and 1 filtering out 26 watts of IR light, preventing it from being transmitted through the disk 1. Of the filtered IR radiation, 0.14 watts reach the photovoltaic cell 8.

[0049] According to the invention, the IR radiation is filtered out very well and, in addition, is partly directed onto the photovoltaic cell 8, so that a holographic solar window 1 is present.

[0050] Another advantage of window 1 is that not only is the IR radiation with the predetermined wavelengths of 850 nm and 1250 nm filtered out, but also the areas A and B with longer wavelengths besides these two wavelengths 850 nm and 1250 nm are obviously filtered out, as a comparison of these areas A and A' and B and B' in Figures 5 and 6 clearly shows.

[0051] Therefore, window 1 can also be described as insulating glass or thermal insulation glass, since only a fraction of the incident IR radiation is transmitted.

[0052] For example, a semiconductor material can be used for photovoltaic cell 8. Monocrystalline silicon or CIGS (copper indium gallium diselenide) can be used, for instance.

[0053] Furthermore, as shown in Figure 8, it is possible to provide an imaging optic 14 that focuses the IR radiation propagating in the cavity 6 onto the photovoltaic cell 8. This could, for example, be a cylindrical lens. This makes it possible to reduce the size of the photovoltaic cell 8, which can lead to cost reductions and / or weight reductions.

[0054] Furthermore, the window 1 is not limited to a double-glazed unit. It can, for example, have three or more panes. Figure 9 shows an embodiment in which a third pane 20 is provided, which is connected to the second pane 2 by a further edge seal 21 such that a second cavity 22 exists between the second pane 3 and the third pane 20. The second cavity 22 can also be used as a waveguide for deflected IR radiation. For this purpose, the second pane 3 can have a third hologram 23 and the third pane 20 a fourth hologram 24, which function in essentially the same way as the first and second holograms 10, 11, but are designed for a different angle of incidence and / or one or more different wavelengths from the IR range in order to propagate this corresponding IR radiation in the further cavity 22 to a further photovoltaic cell 25.

[0055] Window 1 can be designed, in particular, as a window or door for a building.

Claims

Patent claims 1. Window with a first pane (2; 3) and a second pane (3; 20) spaced apart from it, wherein the first pane (2) has a first side (4) facing the second pane (3) and the second pane (3) has a second side (5) facing the first pane (2), wherein a cavity (6; 22) is located between the two mutually facing sides (4, 5) which is closed by means of an edge seal (7) and which is filled with a gaseous medium, wherein the two panes (2, 3; 20) are transparent to radiation from the visible wavelength range and radiation from the infrared range, wherein the edge seal (7; 21) is a photovoltaic cell (8;25) has an IR radiation with a predetermined wavelength from the infrared range that converts into electrical energy, wherein the first disk (2) has a first hologram (10) and the second disk (3) has a second hologram (11), wherein the two holograms (10, 11) are designed such that the IR radiation (L1), which has the predetermined wavelength and which strikes the first disk (2) at a predetermined first angle of incidence (ai), undergoes a first deflection at one of the two holograms (10, 11) to the other of the two holograms (10, 11) such that the deflected IR radiation (L2) strikes the other of the two holograms (10, 11) at a second angle of incidence (CG) that is greater than the first angle of incidence (c) and is deflected by it so that it is reflected at a first angle of reflection (ßs) that is greater than the second angle of incidence (03) into enters the cavity (6) and propagates within it to the photovoltaic cell (8; 25).

2. Window according to claim 1, wherein the predetermined first angle of incidence is in the range of 0° - 30°.

3. Window according to claim 1 or 2, wherein the IR radiation in the cavity (6; 22) is propagated such that, after the second deflection at the two holograms, it is guided either directly, by exactly one Fresnel reflection on this opposite side, by exactly one Fresnel reflection on each of the two sides (4, 5) or by several Fresnel reflections on the mutually facing sides of the two disks (2, 3) to the photovoltaic cell (8; 25).

4. Window according to one of the above claims, wherein the first side (4) of the first pane (2) limits the cavity (6; 22) and / or the second side (5) of the second pane (3) limits the cavity (6; 22).

5. Window according to one of the above claims, wherein the first hologram (10) is arranged within the first pane (2) and / or the second hologram (11) is arranged within the second pane.

6. Window according to one of the above claims, wherein the two holograms (10, 11) are transparent to radiation from the visible wavelength range.

7. Window according to one of the above claims, wherein the two holograms (10, 11) do not deflect and / or reflect any radiation from the visible wavelength range.

8. Window according to one of the above claims, wherein the two holograms (10, 11) each cause the deflection of the IR radiation with the predetermined wavelength by reflection.

9. Window according to one of the above claims, wherein both panes are glass panes.

10. Window according to one of the above claims, wherein the second angle of incidence (as) corresponds to the Brewster angle for a Fresnel reflection at the corresponding pane or does not deviate from it by more than 5°.

11. Window according to one of the above claims, wherein the first angle of incidence (ßs) is greater than or equal to 80° and less than 90°.

12. Window according to one of the above claims, wherein an imaging optic (14) is provided which focuses the propagating IR radiation onto the photovoltaic cell (8).

13. Window according to one of the above claims, wherein a third pane (20) is provided spaced apart from the first or second pane, wherein a further cavity (22) is located between the two mutually facing sides of the first or second and the third pane, which is closed by means of a further edge seal (21) and which is filled with a gaseous medium.

14. System with a window (1) according to one of the above claims, a rechargeable battery in which the electrical energy of the photovoltaic cell (8; 25) is stored, and an electric actuator provided in or on the window (1 ), wherein the battery supplies power to the electric actuator.

15. System according to claim 14, wherein the rechargeable battery is attached in or to the window.

16. System according to claim 14 or 15, wherein the rechargeable battery is provided to be replaceable.

17. System according to one of claims 14 to 16, wherein the actuator can open or close the window (1 ), raise or lower a blind on the window (1 ), and / or change the transmission of an electrochromic layer provided on the window (1 ) by applying a potential.

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