AU2012100990A4 - Daylighting arrangements using channel panels - Google Patents

Abstract

Abstract. A channel panel (15) - which is an acrylic (or similar material) sheet into one face of which an array of parallel, thin, equi-spaced slots have been cut using a laser - is mounted outside the top part of a window (11) of a room (10), or outside the top window of the room (10) if it has two windows, one above the other. The channel panel is rotatable about a horizontal axis (17). A louvre structure (12) having fixed, substantially planar slats, is mounted in close proximity to, and covering, the area of window on which light transmitted by the channel panel (15) is incident. The plane of each of the louvre structure slats is at an acute angle e to the horizontal. The position of the channel panel is adjusted, by rotating it about the horizontal axis (17), so that sunlight falling on it leaves the channel panel at an acute angle relative to the horizontal that is substantially equal to the acute angle e. A shelf or awning (20), mounted lower than the channel panel (15), shades at least part of the lower region of the window (or the lower window if the room has two windows). cZ:4 - a o 5 If, I. aI Au I a mC

Description

Regulation 3.2A AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION (Innovation Patent) Name of Applicant/Nominated Person: Rudds Consulting Engineers Pty Ltd Address for Service: Davies Collison Cave, Patent Attorneys 1 Nicholson Street, MELBOURNE, Victoria, 3000. Invention title: "Daylighting arrangements using channel panels" The following statement is a full description of this invention, including the best method of performing it known to us.

2 Technical field. This invention concerns the illumination of a room with natural daylight. More particularly, it concerns arrangements for directing sunlight to the ceiling region deep within a room, so that a diffuse reflective surface of the 5 ceiling provides a natural illumination of the room, from above, over essentially the entire room. Preliminary note. In this specification, including the claims, "directional" terms (such as "top", 10 "side", "upper", "lower", "above", "upwards", "below", "downwardly", "behind", "inside", "outside" and the like), when used with reference to the illumination of a room in a building, have the meaning that such terms have when used with reference to the embodiments illustrated in Figures 1 and 2 of the accompanying drawings. 15 Background to the invention. In any room where a person has to read, write, draw, sew, construct articles or perform experiments (this list is not exhaustive), it is necessary to have good lighting in that room. Good lighting can be achieved conveniently by 20 the provision of an adequate number of appropriately located electric lights. However, at the present time, most users of electricity are conscious of the need to reduce their power consumption, to assist in the reduction of the generation of greenhouse gases and also to save money. With the prospect of mandatory "green ratings" for new commercial buildings, developers and 25 architects are having to give the reduction of power consumption their close attention. The most obvious way of improving the natural lighting of a room is to provide the room with adequate windows, and thus flood the room with 30 natural daylight. However, large windows or many windows do not necessarily represent a good environmental solution to the lighting problem. Unless the windows are shaded, they represent a source of heating of the 3 room when the sun is shining, and a potential sink of heat during the night. Both of these effects have to be compensated by the air conditioning of the building. With a single, large window, there is also uneven illumination in the regions of the room which are most remote from the window; and glare can 5 be a problem close to the window. Sometimes it is not possible to "retro-fit" a window, either because the building construction is unfavourable, or because the cost of replacing tinted or reflective glazing - installed to restrict solar heating of the room - is prohibitive. 10 Skylights have been used, for many years, to provide illumination from the ceiling of a room. Some skylights have complex constructions, such as the skylight, described in the specification of US patent No. 4,883,340, to Richard I. Dominguez, which is fitted with external reflectors that track the sun. However, skylights generally do not provide substantially uniform 15 illumination over the entire room, and skylights may allow heat to be introduced into, or be conducted out of, a room. In many instances (for example, in multi-storey buildings) it is not possible to install a skylight in the ceiling of a room. 20 Another common daylighting device is the solar tube, which is essentially a skylight, fitted to the roof of a building (or to a high point in the wall of a building), that is connected to one end of a duct that has a highly reflective internal surface. At the other end of the duct, a translucent panel is fitted to the ceiling of a room. Solar tubes are widely used in domestic houses, but 25 are rarely practical installations for commercial buildings. Light pipes, which have a similarity to solar tubes, use a solar collector to direct light into a pipe having a highly reflective internal surface, and an aperture in or at the end of the pipe that is remote from the solar collector. 30 Light pipes have been used, successfully, to transport sunlight falling on the collector to an interior room of a building, where the aperture at the end of the pipe forms a light source for the room.

4 The solar tube and the light pipe were early developments of what is now called an anidolic system. Recently, anidolic systems, in which a solar concentrator (typically a parabolic concentrator, mounted on the outside of a 5 building) directs sunlight into one end of a duct, the internal surface of which is highly reflective and the other end of which is positioned to direct light from the duct onto a diffusely reflective surface of the ceiling of a room, have been used to illuminate the interior of the room. Anidolic systems of this type have been reported to increase the interior illumination throughout an 8 10 metres deep room, with an overall improvement in the uniformity of the illumination. Reflection of light is also a feature of light shelves and louvre systems. 15 A light shelf is installed in a window, or externally of the window but close to it, to divide the window into an upper portion (which is above the light shelf) and a lower window portion. Sunlight falling onto the light shelf is reflected by the highly reflective upper surface of the shelf, though the upper portion of the window, and onto the ceiling of the room. The light shelf shades at 20 least part of the lower portion of the window from direct sunlight. Light shelves can be tilted inwardly (to increase the penetration of the reflected light into the room) or outwardly (to increase its shading of the lower portion of the window). The main benefits of a light shelf are (a) the increase in uniformity of the illumination of the room that it can provide, and (b) its 25 relatively low cost. Louvres - generally constructed of horizontal, evenly spaced, reflective slats, the tilt of which is adjustable (manually or by a programmed control mechanism) - have been used for many years to control the lighting and 30 heating of a room when sunlight falls on a window. The louvres, adjacent to the window, may be inside or outside the room. They may be installed between two panes of glass. The slats may have an arcuate cross-section; 5 they may be shaped to reflect sunlight from a range of incident angles onto a ceiling. They are used to redirect incident light and to provide shade and minimise glare. Their main benefit (the reduction of cooling loads in a room, with improved light distribution) is achieved when the control of the slats is 5 with automated systems. Prismatic panels, comprising a series of elongate, horizontal, prisms formed as a panel, have also been used to control light entering a window. An early example of a prismatic panel is the subject of U.S. patent No. 586,220, 10 granted to Olin H. Basquin in July 1897. The prismatic elements of the panel re-direct (by refraction and by reflection at interfaces) a proportion of the incident sunlight towards the ceiling of a room, to improve the uniformity of its overall illumination. 15 Recently, laser cut panels have been used instead of prismatic panels, to achieve a similar effect. Laser cut panels are produced by Solartran, in Brisbane. They are acrylic panels or sheets into one face of which an array of parallel, thin, equi-spaced, slots (air gaps) have been cut, using a laser. The face of the sheet into which the air gaps have been cut may be covered 20 with a second acrylic sheet. Light entering the panel is refracted by the first face of the panel, then internally reflected at an air gap within the panel, to leave the other face of the panel (with a further refraction). The laser cut panel can be installed in a window in the same way as a pane of glass is installed; or it may be installed in the window in a fixed louvre configuration. 25 Ray trace models show that, using a laser cut panel to re-direct sunlight onto a diffusely reflective ceiling, a significantly increased luminance level can be achieved throughout a large room. Similar panels, containing an array of parallel, thin, equi-spaced, air gaps 30 which are not produced using a laser, have been manufactured by other companies.

6 For convenience, the present inventor has coined the term "channel panels" to cover both the laser cut panels and those similar products of other companies. A channel panel is one component of the present invention. 5 Disclosure of the invention. It is an object of the present invention to provide an improved light redirection arrangement for use with a window of a large commercial building, but which may, of course, be used with other buildings. 10 This objective is achieved by mounting a channel panel (as defined above) outside, and in front of, but spaced apart from, the top region of a generally north-facing window of a room of a building. The channel panel is mounted on a frame that extends outwardly from the building. The mounting of the is channel panel is such that incident sunlight on the panel is refracted and internally reflected by the channel panel so that it enters the upper region of the window (which region, for convenience, the present inventor has adopted the term "entrance window"). The entrance window (that upper region of the window) has fixed horizontal louvres mounted adjacent to it, 20 within the room. (Optionally, the fixed louvres may be mounted within the window pane if the window is double glazed.) The slats constituting the louvres are substantially planar, with the plane of each slat making an acute angle with the horizontal, and being inclined upwardly into the room (that is, with the edge of the slat which is on the room side of the louvres 25 being higher than the edge of the slat which is closest to the channel panel). That acute angle is chosen so that any light shining through the fixed louvres in the direction parallel to the plane of each slat, will be incident upon the diffusely reflective ceiling of the room. 30 When the arrangement of the present invention is in use, the channel panel is oriented so that sunlight incident upon it is redirected by the panel to enter the entrance window (the upper region of the window) parallel to the plane of 7 the slats of the fixed louvres. To facilitate this orientation of the channel panel as the sun's elevation changes, the channel panel is mounted for at least partial rotation about a horizontal axis. 5 The arrangement of the present invention also includes a shade member, extending from the lower edge of the fixed louvres (which is also the lower edge of the entrance window), to shade at least part of the lower region of the window (that is, that region of the window that is below the entrance window) from direct sunlight. 10 In the case of new building, the design of the building should be such that a room with which the present invention is to be used has two windows, one above the other. The upper of these two windows is, of course, the entrance window, while the lower window is the "lower region of the window" referred 15 to above. Thus, according to the present invention, a daylight illumination arrangement for a room with a window (or with two windows, positioned one above the other, to form an upper window and a lower window); the upper region of 20 said window being an entrance window (or the upper window being an entrance window); comprises: 1) a louvre structure mounted on or in close proximity to and overlapping said entrance window, said louvre structure having a plurality of fixed, substantially planar, elongate, parallel slats extending horizontally; 25 and 2) a channel panel having an area which is at least equal to (and is preferably greater than) the area of said louvre structure; the channel panel having a plurality of substantially planar, elongate, parallel air gaps therein; 30 characterised in that: a) the plane of each slat of said louvre structure is at a predetermined acute angle relative to the horizonal which is upwards on the room 8 side of said louvre structure; b) the channel panel is mounted on a frame outside said entrance window for partial rotation about a substantially horizontal axis; c) said arrangement includes means for controlling the angular position 5 of the channel panel relative to said axis, to enable the channel panel to be moved to a position in which sunlight falling on the outer face of the panel is redirected by the channel panel (mostly by internal reflection at each of the air gaps) towards said entrance window, and leaves the inner face of the channel panel at an acute angle relative 10 to the horizontal which is substantially equal to said predetermined acute angle; and d) a shade member extends outwardly from the lower edge of said louvre structure, to shade at least part of the lower region of the window (or the lower window) from direct sunlight. 15 The means to adjust the angular position of the channel panel relative to its axis of rotation may be manually operated or it may be an automated means. 20 Conveniently, the shade member is held in position by being mounted on the frame on which the channel panel is mounted. Preferably, the lower region of the window is provided with a venetian blind, to provide (a) additional manual control of the light entering the lower region 25 of the window, and (b) additional shading - if required - from direct sunlight on the lower region of the window (or the lower window if the room has two windows, one above the other). Embodiments of the present invention will now be described, by way of 30 example only. In the following description, reference will be made to the accompanying drawings.

9 Brief description of the drawings. Figure 1 is a schematic side view of a room having an arrangement for illumination with natural light which is in accordance with the present invention. 5 Figure 2 is a perspective sketch - also schematic - showing an exterior view of a building having a room illuminated with natural light by a modified form of the illumination arrangement of Figure 1. io Detailed description of the illustrated embodiments. The room 10 shown in Figure 1 has a north-facing window 11 in one wall, and no other window. The dimensions of the room (height 2800 mm; depth 25000 mm; working surface height 720 mm above the floor) and the window (height 1500 mm; lower window edge 900 mm above the floor) that are is recorded on Figure 1 are only examples of these dimensions. The window 11 has an upper region A and a lower region B. The upper region A (called the "entrance window") has fixed louvres 12 mounted inside the window, adjacent to the window (if the window is double glazed, the 20 fixed louvres 12 may be mounted between the two panes of glass). The horizontal slats of the louvres 12 are planar (although a slat with a slightly arcuate or other slightly non-linear cross-section, which is nevertheless essentially planar, may be used, without a significant deleterious effect on the transmission of light through the slats). The fixed slats of the louvres 12 25 are tilted upwards relative to the inside of the room 10, so that the plane of each slat makes an acute angle 0 with the horizontal. For a room having a depth of about 25000 mm, the angle 0 will be between 0.80 and 1.20. This tilt of the slats of the louvres 12 ensures that light passing through the louvres 12 in a direction parallel to the planes of the slats will illuminate the 30 ceiling 14 of the room 10. The ceiling 14 has a diffusely reflective surface. In the arrangement shown in Figure 1, the lower region B of the window 11 10 has the optional (but recommended) at least one venetian blind 13 fitted on the inside of the window. A person in the room may manually adjust the venetian blind 13 (a) to permit more light to enter the room through the window, for 5 example, on overcast days; and (b) to provide shading of the lower portion of the region B, if necessary, and/or to reduce glare from the window when the sun is shining. A channel panel 15 is mounted outside the window 11, on a frame 16 that, io in the illustrated arrangement, is attached to the walls of the building of which the room 10 is a part. The channel panel 15 extends the entire width of the window 11 and is mounted so that it can be rotated about a horizontal axis 17. The horizontal axis 17 may be at any suitable position relative to the channel panel 15. It is shown at the top edge of the panel 15 in Figure 15 1, but can be approximately at the middle of the sides of the panel 15, as shown in Figure 2. (These are the two currently most preferred locations for the axis 17, but other positions of the axis of rotation 17 can be chosen, according to need or design.) 20 When the illumination arrangement is in use, the channel panel 15 is rotated about the axis 17 until it is in the position where light in the visible spectrum from the sun 18 is incident on the outer face of the channel panel 15, and is redirected in the panel (mostly by total internal reflection at the air gap interfaces), to emerge from the panel 15 at an angle to the horizontal which 25 is equal to (or is substantially equal to) the angle 0. Thus the light that has passed through the channel panel 15 also passes through the fixed louvres 12 and is incident on the ceiling 14 of the room 10. Since the ceiling 14 has a diffusely reflective surface, the light that has been directed onto it by the panel 15 illuminates the entire work area of the room 10 from above. 30 The arrangements shown in the accompanying drawings include a shelf or opaque panel 20, which is also supported by the frame 16. This opaque 11 panel 20 extends outwardly from the building containing the room 10, over the entire width of the window 11, and has its edge which is nearest to the window 11 positioned between the upper region A (the entrance window) and the lower region B of the window. In this position, the opaque panel 20 5 completely shades the central part of the lower region B from direct sunlight when the sun has an elevation that is greater than the angle p. It also serves to stop the transmitted light 22 (which is the sunlight that has not been redirected by the panel 15) from entering the lower region of the window 11. When the sun's elevation is less than the angle p, the venetian blind 13 io should be used to control light and glare within the room 10 near to the window 11. Although a single channel panel 15 has been shown in Figures 1 and 2, if the window 11 is a wide window, or when the building is in an area where is high winds are likely to be experienced, two (or more) channel panels 15 may be mounted, side by side, on the frame 16. As noted earlier in this specification, the angular position of the channel panel 15 relative to the axis 17 may be controlled manually or automatically 20 (using a programmed controller) to ensure that the panel 15 is rotated about the axis 17 by the appropriate amount as the elevation of the sun changes. The shelf or opaque panel 20 may be constructed as an array of elongate, parallel, horizontal slats, in the manner of a "Vergola" (trade mark), with 25 each slat of the "Vergola" construction being rotatable about a respective horizontal axis, to allow light to be transmitted through the panel 20 and be incident on the lower region B of the window 11 on days when the sun is not shining (and on days when high winds are experienced). 30 If the room 10 has been built with two windows, one above the other, instead of a single window 11, the upper of the two windows will be the entrance window (the region A in the arrangement shown in the accompanying 12 drawings) and will have operatively associated fixed louvres 12, and the lower window will be treated as the lower region B of the illustrated arrangement. With two windows, the shelf or opaque panel may be mounted on a separate frame, cantilevered from between the two windows. 5 If the room 10 should have a window facing in a different direction, a venetian blind can be used to control light into the room from that other window. 10 Advantages of the arrangement of the present invention include: a) the arrangement uses known components, arranged to operate in a low cost, novel, yet effective manner; b) the arrangement can be (and should be) included in the design of a new commercial building (preferably with two windows, one above the 15 other), to improve the new building's "green rating"; and c) the arrangement can be readily "retro-fitted" to existing buildings. Engineers and other persons skilled in this field will appreciate that variations of and modifications to the illustrated embodiments of the 20 invention described above may be made without departing from the present inventive concept. 25 30

Claims (5)

1. A daylight illumination arrangement for a room with a window; the upper region of said window being an entrance window; said arrangement comprising: 1) a louvre structure mounted on or in close proximity to and overlapping said entrance window, said louvre structure having a plurality of fixed, substantially planar, elongate, parallel slats extending horizontally; and 2) a channel panel having an area which is at least equal to (and is preferably greater than) the area of said louvre structure; said channel panel having a plurality of substantially planar, elongate, parallel air gaps therein; characterised in that: a) the plane of each slat of said louvre structure is at a predetermined acute angle relative to the horizonal which is upwards on the room side of said louvre structure; b) said channel panel is mounted on a frame outside said entrance window, for partial rotation about a substantially horizontal axis; c) said arrangement includes means for controlling the angular position of said channel panel relative to said axis, to enable said channel panel to be moved to a position in which sunlight falling on the outer face of said channel panel is redirected by said channel panel towards said entrance window, and leaves the inner face of said channel panel at an acute angle relative to the horizontal which is substantially equal to said predetermined acute angle; and d) a shade member extends outwardly from the lower edge of said louvre structure, to shade at least part of the lower region of said window from direct sunlight. 14

2. A daylight illumination arrangement for a room with two windows, positioned one above the other, thereby forming an upper window and a lower window; said upper window being an entrance window; said arrangement comprising: 1) a louvre structure mounted on or in close proximity to and overlapping said entrance window, said louvre structure having a plurality of fixed, substantially planar, elongate, parallel slats extending horizontally; and 2) a channel panel having an area which is at least equal to (and is preferably greater than) the area of said louvre structure; said channel panel having a plurality of substantially planar, elongate, parallel air gaps therein; characterised in that: a) the plane of each slat of said louvre structure is at a predetermined acute angle relative to the horizonal which is upwards on the room side of said louvre structure; b) said channel panel is mounted on a frame outside said entrance window, for partial rotation about a substantially horizontal axis; c) said arrangement includes means for controlling the angular position of said channel panel relative to said axis, to enable said channel panel to be moved to a position in which sunlight falling on the outer face of said channel panel is redirected by said channel panel towards said entrance window, and leaves the inner face of said channel panel at an acute angle relative to the horizontal which is substantially equal to said predetermined acute angle; and d) a shade member extends outwardly from the lower edge of said louvre structure, to shade at least part of said lower window from direct sunlight. 15

3. A daylight illumination arrangement as defined in claim 1 or claim 2, in which, either (a) when said room has one window, the lower region of said window is fitted with a venetian blind, to provide additional manual control of the light entering the lower region of said window, and also additional shading - if required - from direct sunlight on said lower region of said window; or (b) when said room has two windows, said lower window is fitted with a venetian blind, to provide additional manual control of the light entering said lower window, and also additional shading - if required - from direct sunlight on said lower window.

4. A daylight illumination arrangement as define in claim 1, claim 2 or claim 3, in which said acute angle is such that any light shining through said louvre structure in the direction parallel to the plane of each slat therein will be incident upon the ceiling of said room, and said ceiling id diffusely reflective.

5. A daylight illumination arrangement for a room, substantially as hereinbefore described with reference to the accompanying drawings. Dated this twenty-ninth day of June, 2012. RUDDS CONSULTING ENGINEERS PTY LTD By its Patent Attorneys, DAVIES COLLISON CAVE