Exterior wall element for buildings.

The invention relates to an external wall element for buildings according to the preamble of claim 1.

From DE-OS 27 52 178 external wall elements with two parallel disks are known, between which solar cells are arranged to produce energy. However, such outer wall elements are not translucent. From DE-OS 31 25 622 outer wall elements are known which have a fluorescent glass between two parallel glass panes. At the edge of the fluorescent glass Photo elements are arranged to produce energy. This external wall element allows passage of light, but the energy yield of photovoltaic cells is low and also can not be regulated, the incident in the building radiant energy.

DE-OS 30 05 914 describes a solar collector which comprises a disc with numerous juxtaposed holographic elements. Spaced behind the holographic elements are arranged groups of solar cells, which are sensitive to different spectral ranges. The holographic elements focus the radiation of the different wavelengths to the respective associated solar cells. This solar collector is not intended as an outer wall element for buildings and it is not able to light or heat radiation pass so that it can meet any lighting function.

The invention has for its object to provide an outer wall element for buildings, which enables effective utilization of solar radiation for lighting and to heat the building or energy purposes.

This object is inventively by the features specified in claim. 1

In the outer wall element of the invention a disk is provided with at least one radiation collecting holographic element. A radiation receiving element is located behind the holographic element substantially in the focal plane. The disc and the radiation receiving element are movable relative to each other, so that the incident radiation by bundling the radiation receiving element or is wholly or partially conducted past this. This makes it possible, selectively either radiation into the building pass or take advantage of the incident radiation completely or partially for energy. The adjustment of the radiation receiving element with respect to the disk is done either manually by the user or in response to a thermostatic control and lighting of the building.

The radiation receiving elements can be either photoelectric converter, liquid-flow heat collectors, the inlets of optical fibers, heat-absorbing surfaces or reflectors. In the exterior wall element the incident from the sun radiation on the radiation receiving elements is concentrated, while diffuse incident radiation is transmitted. The outer wall element allows both energy and a lighting and space heating with solar energy.

Preferably numerous holographic elements are provided behind each of holographic elements, a radiation receiving element is arranged on the disc. The radiation receiving elements occupy only a part of the total area of ​​the disc. They can be arranged on a second disc, which is displaceable behind the first disc in its entirety. But there is also the possibility of providing the radiation receiving elements individually and to connect them with each other, said free passages or holes are provided between adjacent radiation receiving elements.

The located between the radiation receiving elements ranges can be designed to part translucent and to another part reflective, to change the optical behavior of the outer wall element by the user in such a way can that energy that is not for room lighting or space heating and even for the electric energy production is required to reflect and thus to keep the building cool.

The optical elements on the outer pane are holographic lenses. The holograms are available as a diffraction grating in a layer of the outer pane. Holograms have the property deflect incident light direction selectively. They are generated by two coherent laser beams, which are incident from different directions, are superimposed on each other and form a line pattern by interference of the light density distribution in the photographic coating of the disk. The incident laser beams are not modulated by an image content. When mounted on the outer disk hologram is illuminated from the same direction, has been incident from the one of the hologram-generating rays, and when the light as that of the hologram-producing beam is at the same wavelength, the other hologram-producing beam is reconstructed. If the illumination is with a radiation of a different wavelength, so also there is a reconstruction of the second beam, however, the diffraction angle changes. When such a hologram with polychromatic light, for example white light, is illuminated, it causes a spectral decomposition. This spectral decomposition can be exploited to conduct only suitable for energy wavelengths of the light receiving elements and the other wavelengths, such as those of visible light pass. In this way it is possible to keep the heat radiation from inside the building and at the same time to use for energy, while visible light is transmitted for illumination purposes.

The disc and the radiation receiving elements are movable relative to each in order to selectively supply heat energy to the building can or keep it off. For supplying thermal energy to building the released by the radiation receiving elements radiolucent areas are placed in the focal areas of the holographic elements of the disc. Where, however, radiant heat can be kept away from the building, either reflecting surfaces or radiation receiving elements are placed in the focal areas of the holographic elements.

Further movement of the pane and the radiation receiving elements can be accordingly provided for the purpose of tracking the sun's position, to always be positioned so that the holographic elements to the sun, that the desired portions of the arranged therebehind structure coincide with the internal regions of the outer pane.

The outer pane does not have to be the space enclosing the outside skin of the outer wall element. Before the outer pane can still be arranged a protective screen. In this case, the outer disc between the protective plate and the radiation receiving elements is arranged movably. Advantageously, a protective screen is arranged on the inside of the outer wall element, which forms the chamber-side boundary of the outer wall element.

In the following the invention will be explained in more detail with reference to the drawings of exemplary embodiments.

Show it:<ul><li>Fig. 1 is a schematic front view of the divided areas in optical external wall element,</li><li>Fig. 2 is a vertical section along the line II-II of Fig. 1,</li><li>Fig. 3 is a section along the line III-III of Fig. 2,</li><li>Fig. 4 is a horizontal section along the line IV-IV of Fig. 1, </li><li>Fig. 5 is the same view as FIG. 3 shows another embodiment,</li><li>Fig. 6 is a vertical section through another embodiment of the invention,</li><li>Fig. 7 is a section along the line VII-VII of Fig. 6,</li><li>Fig. 8 shows a further embodiment of the invention,</li><li>Fig. 9 is a side view of a further embodiment of the invention,</li><li>Fig. 10 is a view of Fig. 9 from the direction of arrow X, and</li><li>Fig. 11 is a view of Fig. 10 from the direction of arrow XI.</li></ul>

The outer wall element comprises two parallel sheets of glass, namely the outer disk 10 and inner disk 11. These disks are used in a frame 12 and are arranged at a distance of about 20 mm. The area between the two disks 10 and 11 is empty. This area is sealed against dust from the environment. It can either be filled with air or be evacuated.

The outer disc 10 carries on its inner surface a coating 13 with numerous holograms. This coating 13 can consist of a photo-sensitive emulsion or photopolymers. In the layer 13 checkerboard numerous radiation-collecting optical elements 14 are produced as holograms. These optical elements are holographic lenses whose focal plane is selected so that it coincides with the inside of the housing facing the interior of the inner disc eleventh The optical elements 14 cause a line-shaped focus of the incident radiation along a vertical line, along this vertical line results in a spectral distribution. In FIG. 2, this spectral distribution is indicated. The obliquely incident radiation is focused along the vertical focal line F, the long-wavelength light in the vertical direction is deflected more than the short-wave. The focus of the red light is with F_r referred to and the focus of the blue light with F_b, As seen from FIGS. 2 and 4 can be seen, a spectral performed in the vertical direction along the focal line F.

Behind each of the radiation collecting holographic elements 14 of the outer sheet 10, a radiation-receiving element 15 is disposed on the inner disc eleventh This radiation-receiving element 15 is, for example, a photoelectric converter, such as a solar cell, or the inlet of an optical waveguide arrangement of one or more optical fibers. The radiation receiving elements are arranged along the focal line F, extending in the vertical direction but only over that region for which they are sensitive. In the present embodiment, this is the lower region of that surface of the inner disc 11 corresponding to the field fourteenth The can be seen from Fig. 3, where it is seen that the radiation receiving elements 15 each extend only over part of the height of a panel 14. Since in the horizontal direction a strong focusing is performed, the horizontal extents of the radiation receiving elements 15 are very low. The remaining regions 16, which are free from the radiation receiving elements 15, are translucent. The radiation receiving elements 15, which are solar cells in the present embodiment are connected with thin wires, which are embedded in the disk 11 to dissipate the stresses generated by the solar cells. As is apparent from Fig. 3, assume the radiation receiving elements 15 only a small part of the surface of the disc 11 a. They extend over a maximum of 10% of the area, provided that they are designed for a focused radiation reception.

In order to follow the course of the sun, a translational movement of the two discs 10 and 11 are provided relative to one another, both in the vertical direction and in horizontal direction. Here, for example, the outer plate 10 is moved in such a manner that the radiation receiving elements 15 always receive a maximum of radiation energy.

There is also the possibility of the discs 10 and 11 to move so that the focal line F does not coincide with the radiation receiving elements 15, so that the total solar radiation is supplied by the disc 11 pass the building interior. The user can thus decide whether the solar energy for lighting or heating of the building is to be used or to generate electricity.

The embodiment 5 shown in FIG. Corresponds to the first embodiment, with the difference that the inner disc 11 having other than the transparent regions 16 yet reflective regions 17. The transparent regions 16 and the reflector animal forming regions 17 are of the same size, they are arranged symmetrically around the radiation receiving element 15th This results indicated in Fig. 5, regions A1, A2, A3 and A4. In the region A1, the surface element is reflective over its entire height. From the area A2, a part of the radiation receiving element and another part of the reflecting surface is occupied 17th From the area A3 a part of the radiation receiving element 15, and another part of the transparent surface is occupied sixteenth The A4 range consists over its entire height of transparent area 16 by horizontal displacement of the disc 10, the user can determine in which of the regions A1 to A4, the focal line F falls. In this way the physical behavior of the exterior wall element according to the wishes of the user can be changed. In the area A1, the outer wall element is reflective in the range A2 occurs reflection and power generation in the region A3 light transmission and power generation and in the A4 range exclusively light transmission. Instead of the solar cells and optical fibers can be used. The reflective layer of the areas 17 is applied as a dielectric coating of metal oxide. Also the conductor tracks for the connection of the radiation receiving elements may be provided as the conductor layers on the disk eleventh

If an exact tracking according to the Sun is present, the radiation receiving elements need 15 (and optionally the reflective surfaces 17) to be very small, as is done by the holographic lenses a strong focusing of the radiation. They create major permeable surfaces 16, diffusely transmit the incident light.

In the embodiment of FIGS. 6 and 7 is 10, fixedly mounted with the coating 13, in which the holographic elements 14 are provided in a frame 20 the disc. In the frame 20 a support structure 21 is arranged with the radiation receiving elements 15 moved horizontally under 20th The supporting structure 21 is formed substantially sawtooth-shaped, because in holographic focusing the focal line F is not parallel to the hologram, but the focus F_r for the long-wavelength (red) light at a shorter distance from the hologram than the focus F_b for the short-wavelength (blue) light. The oblique arrangement of the receiving areas can be achieved in that each receiving field the way the focal line follows. The arranged in the radiation receiving elements receiving boxes 15 thus extend - viewed in vertical cross-section - at an acute angle to the disc 10th

In a vertical strip 15a, which corresponds to about one third of the width of a receiving field or a field 14, every radiation receiving element 15 extends over the entire height of the receiving item. In a subsequent strip 15b, which corresponds to only a fraction of the height of the receiving item, the radiation receiving element extends over only the top level of the reception field and in a further strips 15c takes the free area 16 the total height of the receiving item a. All radiation receiving elements 15 are connected with each other in the vertical direction and in horizontal direction, the spaces between two adjacent radiation receiving elements 15 are connected by connecting elements 22nd All radiation receiving elements 15 thus form a unitary support structure 21, which is relatively displaceable parallel to the disc as a whole while maintaining the distance from the disc 10, as indicated by the double arrow 23 in Fig. 7.

By displacing the support structure 21 relative to the pulley 10 can be achieved in that either the strips 15a or 15b, the strips or over the entire height translucent stripes coincide with the focal lines F 15c. When the strips 15a are set to the focal lines F, all of the incident and focused energy is directed onto the radiation receiving elements, so that no radiation reaches into the building. If the strip 15b is set to the focal lines F, only the long-wave radiation implemented in the present example in energy or kept away from the building, while the short-wave radiation is transmitted. however, the full amount of the free area 16 is set to the focal line F, then the total radiation in the building will enter through.

By suitable design of the free region 16 can be achieved by selectively only radiation of a specific wavelength range is transmitted. In this way, the color of the light that is let into the building may be selected.

The free areas 16 know consist of translucent glass or even be simple holes.

It is also possible not to make the transition between the strips 15a, 15b and 15c continuously but stepwise by an oblique boundary line of the radiation receiving element 15th In this way, the proportion and amount of the transmitted light can be changed continuously.

Finally, there is also the possibility of the disc 10 and the support structure 21 relative to each other to move in the vertical direction in order to obtain different colorings of falling into the building light. While in the horizontal relative movement, the amount of transmitted light varies, and thus a dimming effect is achieved, the vertical relative movement is changed, the light color.

In the embodiment of FIG. 8, a frame 24 is provided which supports the vertical plate 10 with a single holographic element 14. The frame 24 has behind the disc 10 to a support structure 21a, in which the radiation-receiving element 15 is disposed horizontally displaceable (double arrow 23). The radiation receiving element 15 is located in the window 25 of the support structure 21a and can be moved such that either section 15a or section 15b with the focal line F of the holographic element coincides 14 or that the radiation receiving element 15 not coinciding with the focal line F. The horizontal movement of the radiation receiving element 15 is carried by a (not shown) adjustment mechanism which engages a pin 26 of the radiation receiving element.

For tracking in relation to the height of the sun, the frame 24 is pivotable about a horizontal axis 27 around.

In FIGS. 9-11 is shown an embodiment in which a plurality of discs 10 are arranged, each with a hologram 14 in parallel. Each of the disks 10 is about a vertical center axis 34 is pivotally mounted, so that a tracking of the discs 10 is possible in accordance with the elevation angle of the sun. From the top of each plate 10 is an aperture 35 in the form of a strip or bar from. The holograms 14 are formed such that the focal line F perpendicular to the window 10 extends substantially as shown in Fig. 9. The diaphragm 35 is disposed along the focal line F. This diaphragm is radiopaque and preferably absorb radiation, so that it can absorb the incident from the sun and bundled by the hologram 14 radiation along the focal line F.

The aperture 35 can be pivoted about the vertical axis 34 relative to the disc 10 as shown in phantom in Fig. 11. In this case the incident radiation along the focal line F is not shaded and allowed to enter the building. If changes of the sun in azimuth, the focal line F rotates around the axis 34 to the position as F 'take. The aperture 35 can be tracked to the azimuth angle such that the position of the diaphragm remains the same with respect to the focal line.

Each aperture 35 consists of an elongate strip 35a can shield the entire length of the focal line F, and a short strip 35b which only the infrared focus F_IR shields the visible light but passes. It can allow either the area 35a or the portion 35b on the focal line F can be adjusted, or the diaphragm 35 is pivoted so far that it completely frees the focal line F.