EP1121564A1

EP1121564A1 - Light element having a translucent surface

Info

Publication number: EP1121564A1
Application number: EP99955833A
Authority: EP
Inventors: Jürgen KLEINWÄCHTER
Original assignee: PowerPulse Holding AG
Current assignee: PowerPulse Holding AG
Priority date: 1998-10-05
Filing date: 1999-10-01
Publication date: 2001-08-08
Also published as: JP2002526741A; BR9914472A; DE19982011D2; AU1262700A; CN1329706A; KR20010089287A; WO2000020805A1; US7227077B2; US20010054252A1; TR200100930T2

Abstract

The invention relates to a light element (1) comprising a translucent surface (2) and an energy transducer (3). The translucent surface (2) is configured in such a way that it only directs the emission of rays which are directly striking the surface (2) to the energy transducer (3). A solar cell (3), a fluid line (13) or an optical fiber (16) is preferably used as an energy transducer. The light element is particularly suited for illuminating areas with diffused light.

Description

Light element with a translucent surface

The invention relates to a light element with a translucent surface.

The flow of light from sunlight through windows, glass facades and roofs leads to lighting in the interior of the room. Very often, however, glare effects, inhomogeneous light distributions and excessive temperature increases occur in the interior due to a too high level. Venetian blinds often lead to the prardoxic situation that the light flow is blocked out so strongly that artificial lighting must be switched on inside the building. The incident light consists of the direct sunlight from the outside and the almost homogeneous hemispherical, i.e. from all directions of the half-space, diffuse light, which can take up to approx. 10% of the direct value depending on the atmospheric conditions.

Because of the necessary shading, the majority of high-rise electrical power consumption occurs in many high-rise office buildings due to the large number of lamps and lighting fixtures in the depth of the rooms. Artificial light sources can be characterized as "radiators with a weak glow effect" and this means that additional electrical energy is required to transport the heat out of the rooms using "air conditioning". Various blind systems have been developed that can be controlled in a transparent or reflective manner in their position relative to the sun so that they reflect the disturbing direct outside light and only let the diffuse light through. In particular, reference is made here to systems of rotating prisms on the market. Here, transparent prism systems reflect the direct sunlight back and, when positioned perpendicular to the sun, let the diffuse light pass through. This enables selective, transparent blinds.

The known systems can improve the lighting conditioning of rooms with windows, glass facades or roofs, but they have the weakness that the hidden direct sunlight - although energetically valuable - is emitted to the outside world by light reflection.

The invention is therefore based on the object of developing a generic light element in such a way that the radiation directly incident on the translucent surface can be used.

This object is achieved with a light element with a translucent surface, which has an energy conductor and in which the translucent surface is designed such that it directs only the radiation directly onto the surface onto the energy conductor.

In the light element according to the invention, the majority of the incident radiation, which is formed by the direct radiation, is thus applied directed an energy conductor to utilize the energy, while the diffuse radiation passes this energy conductor and can be used for lighting. As an energy conductor z. B. an energy converter or a light guide can be used.

Global sunlight is thus treated selectively so that the diffuse component is transmitted and thus serves, for example, the basic illumination of a room, while the direct radiation component penetrates through the translucent surface according to the invention, but in a focal line or a focal point before reaching the interior or in the interior is concentrated.

It is advantageous if the translucent surface has a Fresnel lens, a holographic lens or a refractive optical element. These optical means make it possible to concentrate direct radiation on an energy conductor and to allow diffuse radiation to pass through.

In the focal line or the focal point, systems according to the invention can be arranged, which either converts the concentrated light into heat (thermal solar collector) or electrical current (photovoltaic collector) or, through secondary optics, ensure that focused light is deflected into the depths of the by a targeted deflection is shone behind the light element located room. A preferred embodiment provides that the energy conductor has a solar cell, the heat of which is actively or passively dissipated. Alternatively, the energy conductor can be a fluid line. The heat absorbed there is then fed to a thermodynamic or thermal utilization system.

A third alternative provides that the energy conductor has an optical fiber. The light guide allows the concentrated light to be transported further or the light of several light guides to be further concentrated.

A preferred exemplary embodiment provides that the entry end of the light guide follows the movement of the focal plane and the exit end is directed in a stationary manner onto the energy guide.

In order to protect the light element from wind, weather and dirt, it is proposed that it be arranged behind a translucent protective surface. The protective surface can be an individually designed glass pane that is easy to clean, so that the light element arranged behind it with its special optical structure no longer requires regular cleaning. The light element is preferably even arranged between two double-pane-like translucent surfaces which offer optimum protection for the light element.

In general, the energy conductor can be arranged between the translucent surface and a further translucent surface. The further translucent surface can be designed as a protective surface or also only direct the radiation directly onto the surface onto the energy conductor.

It is advantageous if the translucent surfaces or the translucent surface delimit a living space. This habitat is then characterized in that only diffuse radiation can be detected in it, since the radiation which strikes the surfaces is directed onto the energy conductor and is thus absorbed before it enters the habitat.

Various exemplary embodiments of light elements with translucent surfaces according to the invention are shown in the drawing and are explained in more detail below.

It shows

FIG. 1 shows a schematic illustration of a system according to the invention with a photovoltaic module,

Figure 2 is a schematic representation of an inventive

Systems with fluid line,

FIG. 3 shows a schematic illustration of a system according to the invention with an optical fiber, FIG. 4 shows a schematic illustration of the use of a system according to the invention for a greenhouse,

FIG. 5 shows a schematic illustration of a climate cushion,

Figure 6 is a schematic representation of the use of a climate cushion for a greenhouse and

Figure 7 schematically shows the energy flows on the climate cushion.

The light element 1 shown in FIG. 1 essentially consists of the translucent surface 2 and the energy conductor 3. In the exemplary embodiment shown, the energy conductor 3 is designed as a photovoltaic element which is arranged between the translucent surface 2 designed as a Fresnel lens and a window pane 4.

The radiation 6 emanating from the sun 5 falls on the translucent surface 2 as direct radiation 7 and diffuse radiation 8. The radiation 7 incident directly on the translucent surface 2 is concentrated on the photovoltaic collector 3 by the Fresnel lens and the diffuse radiation 8 passes through the Fresnel lens and the window pane 4 arranged behind it.

The Fresnel lens 2 can image in a point-like or linear manner in order to concentrate the radiation on a point-like or linear energy conductor. In addition, the Fresnel lens 2 can be tracked with one or two axes of the sun 5 in order to combine a high proportion of direct radiation in a focal line or in one focal point. Here is the energy conductor 3, which converts the radiation energy into electrical energy. The diffuse radiation component 8 of the sun 5 penetrates through the lens without hitting the energy converter and thus reaches a space 9 to be illuminated which is located behind the window pane 4.

The arrangement according to the invention thus fulfills the condition that, on the one hand, sufficient glare-free light is allowed to pass into rooms 9 behind it and, on the other hand, that the non-transmitted direct radiation component 7 is used in an energetically meaningful manner.

The strip-shaped or circular photovoltaic module 3 has to be cooled since it is operated under concentrated light. An active cooling circuit (with water, for example) is particularly useful, so that the entire system supplies light, electrical current and low-temperature heat (typically: water around 40 - 50 ° C). Silicon solar cells are particularly suitable for the linearly concentrating optics, while gallium arsenide solar cells can be used for the point-concentrating optics.

In FIG. 1, instead of water cooling, cooling fins 10, 11 are shown and the photovoltaic module 2 can be rotated about the axis 12 in order to track the sun 5. FIG. 2 shows a system which is similar in construction, in which a fluid line 13 is provided instead of a photovoltaic module. This fluid line 13 allows the additional production of thermal energy. It is an externally blackened, hollow absorber tube (in the case of using a linearly focusing optics) or an externally blackened absorber ball (in the case of using a point-focusing optics). The fluid 14 to be heated, which can be a gas or a liquid, circulates inside the tube or ball. The axis of rotation of the corresponding one-dimensional focusing optics lies in the central axis of the absorber tube 13 and the focal point of a two-dimensionally focusing optics analogously to this is the center of an absorber ball.

To improve the thermal efficiency of the absorber 13, it can be surrounded by a transparent cladding tube or a cladding ball 15. The space between the casing 15 and the absorber can be evacuated and the blackening of the absorber surface can be carried out in such a way that as large a portion of the incident, concentrated light flux as possible is absorbed and the heat reflection of the absorber is as small as possible.

The thermal energy obtained in the absorber will be used, for example, for heating, hot water supply or cooling (sorption systems, Stirling chillers, etc.) of the building equipped with the system according to the invention. Basically, thermodynamic machines (e.g. steam turbines or Stirling engines) operate. In the case of linear optics, the usable temperature field is between approx. 50 ° C and 400 ° C, while the two-dimensional focusing optics can go far beyond 1,000 ° C.

A system with a flexible light guide 16 is shown in FIG. With this light guide 16, the light 7 concentrated in the focal line or in the focal point in the form of a concentrated parallelized light bundle is guided specifically into the depth of a building. The light beams converging towards the focal line or the focal point must be parallelized using suitable systems consisting of mirrors and / or lenses to such an extent that the light can be transported out of the focal line or focal point area without excessive divergence over the desired distance to the desired location. Since the angle of incidence in the area of the focal line or the focal point is constantly changing due to the sun-tracked optics, such deflecting parallelizing additional optics must generally be tracked in such a way that the destination is constantly illuminated in accordance with the optical conditions of incidence and failure. In the present exemplary embodiment, this is solved with the aid of a flexible, strip-shaped (in the case of linearly focusing optics) or circular (in the case of two-dimensional optics) light guide. The parallel incident direct radiation 7 is deflected via the Fresnel lens 2 into a converging beam with the angle 17. The flexible light guide 16 captures rays from a solid angle range greater than or equal to the angle 17 and transmits them on the inside by total reflection. Since the light guide 16 is flexible, its light entry end 18 is connected to the sun-tracking optics in such a way that the entry end is always perpendicular to the optical axis of the incident light beam on the one hand and the axis of rotation or the pivot point of the optical system runs through this entry end. In this way it is ensured that the concentrated, direct sunlight is coupled into the flexible light guide at every position of the sun.

The outlet end 19 is positioned by the holding device 20 so that it points continuously in the direction of the destination 21. The light emerging divergingly from the light guide exit end 19 at an angle 22 is parallelized by a suitable optical arrangement as far as is necessary for the respective lighting case. In the present case, this is achieved by combining two concave mirrors 23, 24 located opposite one another. In principle, however, pure lens systems located in the exit light beam are also possible.

The systems described show that the use of optical systems which allow diffuse daylight to be transmitted, but which bundle direct daylight into spatially clearly defined focal zones, can be used both for pleasant, glare-free interior lighting of buildings and, at the same time, heat for these buildings, Can generate cold and electrical power and can illuminate distant zones. For reasons of weight and cost, Fresnel lenses are used in the exemplary embodiments described. In principle, however, the principle according to the invention can also be used holographic lenses or refractive optical elements.

The lens system can be placed in front of or behind an existing building window, a glass facade or a glass roof. In systems behind a pane, i.e. inside the building, the unwanted heat load emanating from the radiation receivers and radiation converters in the focal lines or focal points can be reduced to a minimum by appropriate heat insulation and routing of the fluid flow to the outside.

In principle, lens systems that are installed behind appropriate windows, facades or light roofs are more advantageous because they fulfill their optical function here, but are not burdened by wind or rain. This leads in particular to a significant simplification of the required sun tracking system, since materials, gears and mechanisms which are arranged behind windows can be made much cheaper, lighter and more energy-efficient and durable.

An embodiment of an installation of a light element 30 according to the invention behind a translucent protective surface 31 is shown in FIG. The greenhouse 32 shown has an outer glass house wall, which forms the translucent protective surface 31. Beneath them are the lenses 33, which are indicated as a dash-dotted line. These lenses 33 concentrate the direct solar radiation 24 on the pipelines 35. A fluid flows in the pipelines 35 and is collected in the heat accumulator 36. For example, at night, fluid heated from the heat accumulator 36 can be removed by means of the pump 37 in order to heat the greenhouse 32 via the line system 38. The plants 39 standing in the greenhouse 32 essentially receive only the diffuse light that penetrates through the lenses and, if necessary, also some direct light that penetrates through the roof surfaces not covered by lenses. In order to convert this light, which is incident between the lenses, into diffuse light, a highly transmissive, preferably textile, light fabric can be arranged in these areas, which converts direct light into diffuse light with high efficiency by forward scattering.

A light, modular element 40 is shown in FIG. According to the invention, the optical lens systems 41 and the

Light collection and conversion systems arranged inside a pneumatically shaped, transparent cushion system 42. The cushion 42 consists of highly transparent, mechanically robust and weather-resistant

Fluoropolymer films. It is formed from two transparent foils 42 and 44 which are shaped like pillows by internal air overpressure and are held along their circumference by a mechanically stable profile 45.

The axis of rotation and fluid lines of the also run through this profile

Lens system 41. With the help of the profiles 45, the pillows 42 can thus

Sun 46 are tracked that the direct radiation 47 hits the upper cushion cover 43 as vertically as possible. FIG. 6 shows how the shell of a greenhouse 51 can be formed from a plurality of pneumatic cushion elements 50. The plants 52 inside the greenhouse 51 thereby receive enough light at pleasant temperatures. The lens system 53 generates a hot fluid, which is fed via a line 54 to a thermodynamic machine 55. In this case, stream 56 is produced and the cooled fluid is fed back to the lens system 53 via the line 57. The optional interposition of a heat store 58 enables the energy generation system 55 to bridge bad weather periods and in principle also work during the day and at night.

Such greenhouses are particularly useful in semi-arid and arid climates. The conditioned indoor climate allows optimal plant growth. The energy generated in the shell can be used to supply the energy required in such modular "oases" that can be expanded.

However, completely new types of solar power plants can be built to produce and distribute electricity. The required footprint is not lost, but on the contrary is automatically upgraded, since, as described, it creates optimal living and working conditions for plants and people.

FIG. 7 shows schematically the energy flows in and out of the energy and climate envelope. The incident solar globular radiation 60 consists of the spectral ranges A, B, C. A is the short-wave, invisible UV Spectrum, B the visible spectrum and C the long-wave, invisible infrared spectrum. This global radiation is converted inside the climate and energy envelope 61 by the lens systems and energy conductors into heat, cold, electrical current and directional, concentrated light 62. The types of energy shown can be generated either exclusively or in any combination with the others.

The diffuse component 63 from the incident global radiation is not bundled by the lens system and therefore reaches the room 64 behind or below the energy climate envelope as diffuse, glare-free light.

The system according to the invention represents a versatile solar component. It can be used as a window, facade or roof element in conventional buildings up to the construction of complete, multifaceted building envelopes. The interior of such buildings is air-conditioned in terms of heat and light, and the envelope itself generates the additional energy required.

Claims

Claims:

1 . Light element with a translucent surface, characterized in that it has an energy conductor and the translucent surface is designed such that it directs only the radiation directly onto the surface onto the energy conductor.

2. Light element according to claim 1, characterized in that the translucent surface has a Fresnel lens, a holographic lens or a refractive optical element.

3. Light element according to one of the preceding claims, characterized in that the energy conductor has a solar cell.

4. Light element according to one of claims 1 or 2, characterized in that the energy conductor has a fluid line.

5. Light element according to claim 1 or 2, characterized in that the energy conductor has a light guide.

6. Light element according to claim 5, characterized in that the light guide is flexible.

7. Light element according to claim 5 or 6, characterized in that the entry end of the light guide follows the movement of a focal plane and the exit end is fixed to the energy conductor.

8. Light element according to one of the preceding claims, characterized in that it is arranged behind a translucent protective surface.

9. Light element according to one of the preceding claims, characterized in that the energy conductor is arranged between the translucent and a further translucent surface.

10. Light element according to one of the preceding claims, characterized in that translucent surfaces delimit a living space.