WO1999046473A1

WO1999046473A1 - Shading installation with blades

Info

Publication number: WO1999046473A1
Application number: PCT/EP1999/001469
Authority: WO
Inventors: Fritz Harald Klotz
Original assignee: Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg
Priority date: 1998-03-11
Filing date: 1999-03-08
Publication date: 1999-09-16
Also published as: ATE239853T1; PT1068422E; EP1068422B1; AU3032199A; DE59905465D1; EP1068422A1; WO1999046473A9; DK1068422T5; EP1068422B9; ES2200510T3; DE19810436A1; DK1068422T3

Abstract

The invention concerns a shading installation comprising a row of shading blades each arranged so as to be able to pivot about a longitudinal axis (3 to 8) extending transversely relative to said row direction (R). The invention is characterised in that the row of blades consists of two groups (1a, 1b, 1c; 2a, 2b, 2c) of different shading blades alternately arranged, the blades of one group capable of being tilted in the same direction, and relative to the other group, in opposite direction. The first group (1a, 1b, 1c) can be provided with solar energy converting and/or light collecting elements. Said installation can be used, for example, as sun protection for building fronts or transoms, while enabling photovoltaism.

Description

Louver shading system

The invention relates to a shading system according to the preamble of claim 1.

Shading systems with a row of shading slats, which are each pivotably arranged about a longitudinal axis running transversely to the row direction, are used, for example, for shading large facade or window surfaces on buildings, in particular on vertical facades and on inclined surfaces of skylights. In most known shading systems of this type, in contrast to the existing, generic type of system, all slats are pivoted in the same direction. Systems of this type are also known which, in addition to their shading function, also perform an additional function converting solar energy, for which purpose the row of slats is equipped with photovoltaic elements. The term photovoltaic elements here means photovoltaically active components of any conventional type. Such shading systems are offered, for example, by Colt International Limited, Hampshire, Great Britain, and are described in a company brochure from the same in 1994 and in the published patent application DE 43 02 883 AI. In these shading systems, all slats can be swiveled synchronously and in the same direction from a closed position as a first end position to a maximally open position as a second end position and back again, for what purpose, by means of an actuator about horizontal axes, preferably in the east-west direction they are coupled to an electromotive or electro-hydraulic actuating mechanism via a common actuating rod. In the closed position, the slat surfaces lie on one level, leaving any gaps, and are therefore fully facing the incident sunlight. By steplessly pivoting up to the maximum open position, more diffuse daylight is let through, and at the same time, in many applications, in particular in the case of vertical slat axes one above the other, the slat surfaces can be aligned at least approximately perpendicular to the direction of sunshine. The vertical incidence of light increases the specific energy yield of the photovoltaic elements. However, at the same time there is the problem that the more the slats are opened, the more they partially shade from the incidence of sunlight. Therefore, in this known type of system, a part of the photovoltaic elements applied to the slat surfaces remains unused in the open slat positions, or the photovoltaic elements are only arranged in the part of the slat surfaces not subject to shading. This limits the specific energy yield of photovoltaic energy generation with this system.

From the patent FR 2 110 753 a slat shading system is known with a row of slats of the same size, which are each pivoted about a longitudinal axis running transversely to the row direction by the same swivel angle such that the opposite outer edges of each adjacent slat approximately on a connecting line parallel to the direction of sunlight lie. The result of this is that direct sunlight only hits the lamella surfaces perpendicularly in the singular case that the direction of sunlight incidence is orthogonal to the plane of the lamella pivot axes, while it strikes all lamella surfaces obliquely for all other directions of incidence.

As an alternative to pivoting all slats in the same direction, shading systems of the generic type have also been proposed, in which the slats are pivoted alternately in opposite directions. The utility model DE 1 734 532 discloses such a system in the form of a louvre flap with a special lever mechanism for pivoting adjacent slats in opposite directions by pivoting angles of the same or similar size.

Another generic shading system is described in the published patent application FR 2 691 744. In this system, adjacent slats are pivoted in opposite directions by the same swivel angle using a special cable pull mechanism.

The invention is based on the technical problem of providing a louvre shading system of the type mentioned, in which the desired shading function is optimally performed and the least possible mutual shading of the louvres occurs, so that the system is good for an additional solar energy converting and / or light collecting when needed Function can be used.

The invention solves this problem by providing a shading system with the features of claim 1. In this system, the row of slats contains two groups of different, alternately arranged slats, namely a group of idler slats, which are preferably intended to follow the changing position of the sun, ie to be tracked, and a group of counter-rotating plates, which are arranged in the row alternately to the idler plates. The slats of the respective group are swiveled in the same direction among themselves, but those of one group in opposite directions to those of the other group. The pivoting takes place in a special manner such that the opposing areas of adjacent slats are at least approximately next to one another and consequently not one behind the other within a pivoting area containing the closed position in the projection to the direction of sunlight. In other words, there is no significant overlap of the opposing areas when viewed in the direction of sunlight. adjacent slats and therefore no significant mutual shading of the slats.

By means of this special pivoting movement of the counter-rotating plates arranged alternately to the pivoting movement of the idler plates, the mutual shading of the plates among each other within a swivel range of, for example, approx. ± 60 ° with respect to the closed position of the plate row, which is sufficient for most applications, can be completely avoided and at the same time an optimal Fulfill the shading function with which uncontrolled direct light can be practically completely avoided.

In a shading system developed according to claim 2, the idler blades, i.e. only every second slat in the slat row, covered with solar energy converting and / or light collecting elements, e.g. with photovoltaic elements or light concentrator elements. Because of the greatest possible freedom from shading, the follow-up slats can be provided with such elements over the entire surface and can track the position of the sun within the said swiveling range of typically up to 120 °, without significant shadowing of this full-surface occupancy occurring. Since the solar radiation from the elements using the sun can thus be used well over the entire course of the day and without significant shading, a comparatively large solar energy yield results for a given total area of the slats despite the fact that these elements are only alternately covered with these elements.

In a further developed in accordance with claim 3 shading system, the opposite pivoting movement of the counter-rotating blades to the pivoting movement of the idler blades is optimally controlled so that at least within a pivoting area containing the closed position of the row of blades, the facing outer edges are adjacent in each blade position Lay the slats on a connecting line that runs approximately parallel to the direction of sunlight. Any shading of the adjacent slats is thus avoided within this pivoting range. Given the same width of the slats of the two groups, this completely shadow-free swivel range for the idler slats is at least approx. ± 60 ° around the closed position, which enables sunlight to be tracked over a correspondingly large angular range. In this case, the counter-rotating plates pivot about half the pivoting angle of the idler plates. With the width of the counter-rotating lamellae becoming smaller compared to the width of the idler lamellae, the completely shading-free swivel range is reduced somewhat, but a certain excess of this swivel range, which is accompanied by the beginning of partial shading of the idler lamellae, can still be tolerable in some cases.

In a shading system developed according to claim 4, the counter-rotating slats are designed to control the light control, i.e. provided with appropriate light-directing elements, such as light-reflecting, light-scattering or the direction of transmitted light-controlling elements. The counter-rotating slats can thus specifically fulfill a desired shading functionality. You can e.g. be designed so that they direct the daylight into an interior of the building through refraction and / or reflection. By realizing the counter-rotating lamella as a light reflection surface, the incident light can also be reflected to an adjacent tracking lamella if necessary and there in addition to the direct sunlight, e.g. be used photovoltaically, especially if the slats are already noticeably tilted relative to the closed position.

In a shading system further developed according to claim 5, the row of slats is arranged with longitudinal longitudinal slat axes extending transversely to the horizontal. The pivot axes are preferably parallel to or opposite to the vertical this is inclined at an acute angle. Optimal sunlight yield is achieved by a north-south orientation with an inclination corresponding to the polar axis. The arrangement of the slat swivel axes transversely to the horizontal has the great advantage that the idler slats can track the sun's course from east to west. Investigations show that this tracking, under otherwise identical conditions, enables a higher photovoltaic yield than tracking with respect to the height of the sun with horizontally arranged slat swiveling axes.

In a shading system developed according to claim 6, a tracking device for automatically pivoting the idler slats depending on the position of the sun is provided. This means that the optimal east-west tracking can be implemented in the case of slat swiveling axes running transversely to the horizontal, but depending on the application, any other conventional sun tracking, such as one depending on the height of the sun. In a conventional manner, the tracking device can include an electromotive, electrohydraulic or thermohydraulic actuator for the idler plates.

In a shading system developed according to claim 7, a linkage is provided with which the idler plates can be pivoted synchronously coupled. In particular, the linkage in connection with the tracking device according to claim 5 is suitable for automatic tracking of the sun position of the idler plates.

In a shading system developed according to claim 8, the counter-rotating lamellae are coupled in opposite directions to the pivoting movement of the idler lamellae via a mechanical coupling mechanism, for example a simple lever arm or a four-bar linkage. This saves an independent drive for the counter-rotating slats and guarantees a defined pivotal pivoting movement of the same with respect to the idler plates.

In a shading system developed according to claim 9, the idler blades are always pivoted within the shading-free pivoting area containing the closed position so that the sunlight strikes the lamella surfaces of these lamellae orthogonally in the projection to the plane perpendicular to the lamella pivot axes. In this way, an optimal efficiency for solar energy use can be achieved if these tracking lamella surfaces are covered with corresponding solar energy use elements.

Advantageous embodiments of the invention are shown in the drawings and are described below. Here show:

1 is a schematic, partial side view of a photovoltaically active louvre shading system with idler blades and counter-rotating blades in an alternating arrangement and a tracking device with coupling linkage,

2 is a view corresponding to FIG. 1, but for a shading system with a modified coupling linkage,

Fig. 3 is a schematic side view of a lever gear for the coupling linkage of Figs. 1 and 2 and

4 to 7 a schematic side view of two adjacent idler plates and an intermediate opposed plate of the systems according to FIGS. 1 and 2 in successively more tilted positions.

The slat shading system shown in Fig. 1 includes a row of slats with a group of idler slats la, lb, lc and an alternately arranged group of counter-running lamellae 2a, 2b, 2c, so that along the row direction R one idler lamella and one counter-running lamella follow each other. The idler blades la, lb, lc are covered over their entire area on their side facing the sunlight with photovoltaic elements of any conventional type, such as thin-film solar cells made of monocrystalline, polycrystalline or amorphous silicon, and are therefore referred to below as photovoltaic blades. An overview of usable solar cells can be found in W. Wettling, Solar Cell Technology - State of the Art and Trends, Conference Volume 12. Symp. Photovolt. Solarenergie, 1997, p. 35. All shading slats la, lb, lc; 2a, 2b, 2c are arranged so as to be pivotable about their respective longitudinal central axes 3, 4, 5, 6, 7, 8, the photovoltaic slats la, lb, lc being pivoted in the same direction and synchronously. Likewise, the counter-rotating blades 2a, 2b, 2c are pivoted synchronously and in the same direction among themselves, but in opposite directions. the photovoltaic slats la, lb, lc. In the example shown, the photovoltaic slats la, lb, lc and the counter-rotating slats 2a, 2b, 2c have the same width, which in turn corresponds approximately to the distance between adjacent pivot axes 3 to 8, so that the row of slats in the closed position shown represents an essentially closed shading area. Both types of lamellae la to 2c are not completely opaque to fulfill the shading function, but rather are designed to be translucid, ie partially translucent for visible light, so that glare-free lighting of the shaded room is achieved by sunlight and daylight.

The swiveling movement of the slats takes place automatically through a tracking device, of which only an associated actuator is shown, while its other components are of a conventional nature. The actuator contains a hydraulic drive unit 9, alternatively an electromotive or thermohydraulic drive unit to which a coupling linkage is coupled. The coupling linkage includes a first coupling rod 10 which is coupled to the drive unit 9 at one end in a longitudinally movable manner and to which all photovoltaic lamellae la, lb, lc are coupled via associated link arms lla, 11b, 11c in such a way that they are caused by the longitudinal movement of the first caused by the drive unit 9 Coupling rod 10 can be pivoted synchronously in the same direction. For this purpose, the link arms 11a, 11b, 11c are on the one hand rotatably connected to the first coupling rod 10 and, on the other hand, non-rotatably connected to a respective slat rotary shaft which represents the pivot axis 3, 5, 7. The counter-rotating lamellae 2a, 2b, 2c are coupled together via analogue link arms 13a, 13b, 13c to a second coupling rod 12 for the purpose of joint, synchronous pivoting.

A lever mechanism ensures that the pivoting of the counter-rotating blades 2a, 2b, 2c takes place in the opposite direction to that of the photovoltaic blades la, lb, lc with a defined translation, which in this example is selected so that the pivoting angle of the counter-rotating blades 2a, 2b, 2c in Is almost half as large as the swivel angle of the photovoltaic slats la, lb, lc. The lever mechanism couples the first counter-rotating lamella 2a in the direction of the drive unit 9 to the adjacent, end-side photovoltaic lamella la, so that the rotary movement actively caused by the drive unit 9 is translated by the lever mechanism, specifically reduced here, and in opposite directions to the first counter-rotating lamella 2a and from there is transmitted synchronously to the remaining counter-rotating plates 2b, 2c via the second coupling rod 12. For this purpose, the lever mechanism has a lever arm 14, on each end of which a coupling arm 15, 16 is articulated, the other end of which is connected in a rotationally fixed manner to the rotating shaft 3 of the first photovoltaic plate 1a or the rotating shaft 4 of the first counter-rotating plate 2a.

While in the example of FIG. 1 the two coupling rods 10, 12 are arranged on opposite sides of the row plane along one side of the row of slats, FIG. ne variant in which the two coupling rods 10, 12 are arranged on the same side of the row plane. Otherwise, this variant corresponds entirely to the example of FIG. 1, which is clarified by the fact that the same reference numerals are used for functionally identical elements, so that reference can also be made to the explanations for FIG. 1.

Fig. 3 illustrates in more detail the principle of operation of the lever gear in a concrete design. Here, a desired swivel range of the photovoltaic slats of ± 60 ° around the closed position shown in FIGS. 1 and 2 is predetermined, which corresponds to an equally large angle of rotation range γ of the coupling arm 15 which is non-rotatably seated on the photovoltaic slat rotating shaft 3. Via the lever arm 14, this angle of rotation range γ of 120 ° is transformed into a half as large an angle of rotation range δ of 60 ° for the coupling arm 16, which is non-rotatably seated on the counter-rotating disk rotating shaft 4. In order to achieve a good power transmission behavior, the coupling arms 15, 16 and the lever arm 14 are matched in length and positioning so that the lines of action of the lever arm 14 in the end positions, one of which is shown in FIG. 3, coincide approximately and with the Bisector W of the swivel range γ of the photovoltaic plate coupling arm 15 form a right angle. The angular positions indicated by dashed radius beams in 20 ° steps from + 60 ° to -60 ° of the photovoltaic lamella coupling arm 15 correspond to the angular positions -27.1 °, -20.1 °, -11.1 °, in the counter-rotating lamp arm 16. 0 °, + 12.4 °, + 22.9 ° and + 32.9 ° in this order. The simple lever mechanism shown can be implemented with little effort and approximately symmetrically to the closed position, although not exactly, fulfills a rotation angle ratio which ensures freedom from shading. Exact compliance with this ratio can be achieved by using a belt drive or the like. or separate drives for the two slat groups possible. 4 to 7 illustrate the mode of operation of the shading system according to FIGS. 1 and 2, taking two adjacent photovoltaic slats 1b, 1c and an intermediate opposing slat 2b as an example, schematically in different tilt positions. The row of lamellae is spatially oriented in this example in such a way that the lamella pivot axes 5, 6, 7 lie in a north-south plane, for example vertically or with an oblique angle to the vertical corresponding to the polar axis inclination. For clarification, the cardinal points are given in these figures as an example for the case that the system is located in the northern hemisphere. The photovoltaic elements of the photovoltaic slats lb, lc are accordingly located on the slat side facing south.

Fig. 4 shows the three blades lb, lc, 2b in the closed position, i.e. at a swivel angle of 0 °. The closed position shown is ideal for the midday, when the sunlight shines with the greatest intensity from the south. The closed slats offer their full shading effect, and at the same time the sunlight falls on the photovoltaic elements as vertically as possible for a given position of the shading system, so that an optimal photovoltaic yield is achieved.

Over the course of the day, the photovoltaic lamellae lb, lc are tracked by the tracking device in the east-west direction to the moving position of the sun by pivoting about their pivot axes 5, 7 within a pivoting range of ± 60 ° around the closed position so that the sunlight is always as vertical as possible the photovoltaic elements are incident, ie in such a way that in the cross-sectional view of the lamella system represented by FIGS. 4 to 7, the corresponding projection of the direction of incidence of sunlight is perpendicular to the surfaces of the photovoltaic lamellae. 5 to 7 illustrate selected lamella positions with a successively increasing swivel angle. 5 shows a position with photovoltaic lamella lb, lc tilted to the east by a swivel angle β of 30 °, while in opposite directions the counter-rotating lamella 2b is tilted to the west by a swivel angle α. The opposite coupling of the counter-rotating blades with the photovoltaic blades is chosen in this illustration example so that the swivel angle α of the counter-rotating blades amounts to approximately 42% of the swivel angle of the photovoltaic blades. From Fig. 5 it can be seen that on the one hand the incident sunlight 20 in the projection of the plane of the drawing strikes the photovoltaic lamella lb, lc perpendicularly and on the other hand the tangents 21 to the edges of the photovoltaic lamella lb, lc just the edges of the adjacent ones Strip the counter-rotating lamella 2b. This means that the slats continue to perform their full shading function, ie there is no direct. Sunlight through the row of slats. At the same time, with increasing pivoting from the closed position in the direction of the respective end position, the row of slats opens increasingly for diffuse sky light, which in this way increases the daylight quotient of the shaded room without a disturbing glare. The proportion of sunlight impinging on the counter-rotating lamellae 2b is not used photovoltaically, but can be used for other purposes, for example for targeted, desired daylight illumination of the room behind it. For this purpose, the counter-rotating lamellae 2b can be equipped with suitable light-directing elements, for example with light-scattering elements and / or elements controlling the direction and intensity of the transmitted light, such as prisms etc.

6 shows a slat position in which the photovoltaic slats 1b, 1c are pivoted to the east by a pivoting angle β of 50 °. Again, the sunlight 20 in the horizontal projection shown hits the photovoltaic lamella lb, lc at the appropriate time of day, and here, too, the tangents 21 touch the edges of the photo- voltaic lamellae lb, lc just the edges of the counter-rotating lamellae 2b, so that again no direct sunlight can pass through the row of lamellae. In addition, FIG. 6 illustrates the case in which the respective counter-running lamella 2b is designed to be reflective, for example by being made of mirror glass. This enables an additional photovoltaic use of the sunlight striking the respective counter-rotating lamella 2b, represented in FIG. 6 by a corresponding strip area 20a, in that it is reflected by the counter-rotating lamella 2b to the photovoltaic lamella lc adjacent to the west and there in addition to the directly incident sunlight in electrical energy can be implemented. This further increases the energy yield of the shading system. It goes without saying that the additional photovoltaic use of the sunlight striking the respective counter-rotating lamella 2b and reflected to an adjacent photovoltaic lamella lc is achieved not only in the lamella position shown in FIG. 6, but also for positions with relatively larger or somewhat smaller pivoting angles.

FIG. 7 shows the lamella arrangement in its one end position, in which the photovoltaic lamella lb, lc are pivoted the farthest to the east by a swivel angle β of 60 °. Again, the position is selected depending on the position of the sun so that the sunlight 20 strikes the photovoltaic lamella 1b, 1c perpendicularly in the cross-sectional view shown. Furthermore, in this end position, the tangents 21 coincide with the mutually facing edges of the adjacent photovoltaic slats 1b, 1c and run in the plane of the intermediate counter-rotating slat 2b. As a result, complete shading against direct light incidence is achieved in this end position, too, and solely through the photovoltaic slats lb, lc. If the swiveling was even stronger, shading of the photovoltaic lamellas lb, lc would increasingly occur due to the counter-rotating lamella 2b adjacent to the east, entire described swivel range from the closed position to the photovoltaic slat swivel angle of 60 ° to the east, no shadowing of the photovoltaic slats lb, lc occurs. Rather, the entire area of the photovoltaic slats 1b, 1c can always be used photovoltaically. Together with the efficient east-west tracking, this leads to a comparatively high energy yield for the shading system with a relatively small proportion of photovoltaic space.

A closer look reveals that the condition that the respective photovoltaic lamella tangent 21 in each lamella position within the swiveling range grazes the adjacent, counter-rotating lamella edge and thus forms a connecting line that remains parallel to the direction of incidence of sunlight between the mutually facing edges of adjacent lamellae can then be met, when the swivel angle α of the counter-rotating slats 2b is set according to a determinable analytical function as a function of the swivel angle β of the photovoltaic slats 1b, lc. In the entire swivel range, this analytical function lies relatively close below a straight line connecting the end points, the slope of which in the case of lamellae of the same width described above is 0.5. The maximum misalignment occurs in a middle area between the closed position and the respective end position and is only about 2 °. In a good approximation, this linear relationship can consequently be used in practice, which may be technically easier to implement.

Through the automatic tracking of the position of the sun, the slats are pivoted in the morning into the end position according to FIG. 7, from which they are then successively pivoted back until they reach the closed position of FIG. 4 at noon. They are then pivoted in mirror image to the north-south vertical plane in accordance with the sequence of FIGS. 5 to 7 into the other end position, the photovoltaic lamellas 1b, 1c, ie from the closed position to one by 60 ° West tilted position. In any position, the shading system avoids any direct light, and at no time are the photovoltaic slats shaded, and in the course of the morning and the afternoon, the reflecting counter-rotating slats can reflect the light that strikes them towards the photovoltaic slats and can also be used there for photovoltaic purposes. This can further increase the photovoltaic yield by up to 10%. In addition to directly reflected light, depending on the design of the counter-rotating lamella 2b, diffuse radiation can also be passed on from this to the neighboring photovoltaic lamella lc.

It goes without saying that in addition to the described further implementations of the shading system according to the invention are possible. The counter-rotating blades can have a different width than the photovoltaic blades. In addition, the shading system can be arranged in any other than the spatial orientation shown on a facade or a skylight of a building or the like. Both solar cells of the common types with a light absorber thin film and so-called light antenna solar cells with a nano-metal structure or electrochemical solar cells can be used as photovoltaic elements. Instead of using photovoltaic elements, the tracking slats can also be equipped with other solar energy converting elements, such as flat absorbers or vacuum tube collectors for solar thermal conversion, or with light collecting elements, such as e.g. with lenses or reflectors to which light guides can be coupled in order to use the collected light for use, for example, for controlled, uniform interior lighting. The counter-rotating lamellae are preferably designed so that they fulfill the desired daylighting and shading functionality by means of diffraction, refraction or reflection of the direct or diffuse solar radiation. As a positive side effect, the reflected radiation can support the energy decoupling function of the idler plates.

Claims

Expectations

1. shading system with a row of shading slats (la, lb, lc, 2a, 2b, 2c), each of which is arranged to pivot about a longitudinal axis (3 to 8) running transversely to the row direction (R) and consists of a group of idler slats (la , lb, lc) and a group of alternately arranged counter-rotating lamellae (2a, 2b, 2c), the lamellae of the respective group being pivoted among themselves in the same direction and with respect to that of the other group, characterized in that the opposite pivoting movements of the two lamella groups ( la, lb, lc; 2a, 2b, 2c) are controlled depending on the position of the sun in such a way that at least within a swivel range containing the closed position of the row of slats in each slat position, the opposing areas of adjacent slats remain approximately free of shading in the projection to the direction of sunlight.

2. Shading system according to claim 1, characterized in that the idler blades (la, lb, lc) are covered with solar energy-converting and / or light-collecting elements.

3. Shading system according to claim 1 or 2, further characterized in that the mutually opposite outer edges of adjacent slats are at least within a pivoting range containing the closed position of the row of slats in each slat position approximately on a connection line parallel to the direction of sunlight (21).