GLAZING PANEL

Abstract: A glazing panel suitable for skylights, windows and glasshouses is constructed so that, by selectively positioning it in relation to the direction of the sun, the amount of solar energy transmitted through the panel can be regulated. The glazing panel comprises a transparent one piece extrusion of two parallel sheets (12 and 14) spaced by ribs (16) to form a plurality of side-by-side cells (18) and a plurality of parallel reflective slats (20), one positioned diagonally in each cell. As shown, the slats (20) point away from the sun so the panel restricts solar transmission but may be repositioned so thatthe slats (20) point towards the sun to permit solar transmission.

Description: Description Title: Glazing Panel Field of Invention: The invention relates to a glazing panel which may be used in the construction of skylights, windows, glasshouses and the like. In particular, the invention is concerned with a glazing panel which may be employed to reduce or increase the amount of solar energy which passes through the panel. Description of the Prior Art: In the construction of buildings, it has long been commonplace to provide means such as skylights and windows for access of light and other solar energy. A consideration in the design of skylights and windows has been the nature of the prevailing solar conditions and the need, for example, to restrict the ingress of light and "other solar energy from a strong summer sun or to maximise ingress in the case of a weak winter sun. To that end, openings in ceilings and walls for skylights and windows have usually been provided with panes of glass or plastics material which may be large or small, single or multiple, clear or coloured, smooth or roughened, painted or engraved, etc. Shutters, blinds and screens etc. have also been used for that purpose. In the field of horticulture, glasshouses have been constructed almost entirely from glass or plastics sheets to provide plants with plenty of light which is generally required for proper growth. However, special shading devices have had to be used to protect tender plants so that they would not be wilted or scorched by a strong sun. OM?I Summary of Invention: It is an object of the invention to provide a glazing panel of such construction that, by selectively positioning it in relation to the direction of the sun, the amount of solar energy transmitted through the panel can be regulated. It is a further object of the invention to provide a glazing panel which may be positioned during winter to transmit solar energy and be reversed during summer to restrict solar transmission. In accordance with the invention, a glazing panel comprises two spaced translucent substantially parallel sheets, a plurality of substantially parallel spaced reflective slats positioned between the sheets, each slat extending the length of the panel, means to space the sheets and to hold the slats in position so that they are substantially equally spaced across the width of the panel and are angularly inclined with respect to the sheets. Brief Description of Drawings: The invention will be described in relation to the use of the glazing panel in a skylight in a horizontal roof. Thus the glazing panel is also horizontal and is removably mounted in the roof aperture so that it can easily be withdrawn therefrom and replaced. Figure 1 is a cross-sectional view of the glazing panel and illustrates how the glazing panel should be positioned during summer with the slats pointing away from the sun (South) ; and Figure 2 is a cross-sectional view of the glazing panel and illustrates how the glazing panel should be positioned during winter with the slats pointing towards the sun (North) . OMPI Description of the Preferred Embodiment: As shown in the drawings, the glazing panel comprises two spaced transparent parallel planar sheets 12 and 14 separated by a plurality of transparent spaced parallel ribs 16 extending between the two sheets 12 and 14 in planes perpendicular to the planes of the sheets. The ribs are spaced across the width of the glazing panel and each rib extends along the length of the glazing panel. There are thus formed a plurality of cells 18, located side-by-side across the width of the glazing panel, each cell extending along the length of the glazing panel with its four sides being formed by the two sheets 12 and 14 and by two adjacent ribs 16. The cross-section of each cell is square or rectangular. The sheets 12 and 14 and the ribs 16 are preferably made of a clear plastics material such as a polycarbonate resin or an acrylic resin and the double skinned plastics section may be formed in one piece by extrusion. Positioned diagonally in each cell 18 is a reflective planar slat 20. Each slat 20 is reflective on both its major surfaces and may be of polished aluminium. The slats are positioned so as to be in substantially parallel planes at an angle of 40° to the planes of the sheets. That angle was chosen because it had been found that the highest percentage of winter solar penetration occurs when the sun's altitude is 40°. In summer, the glazing panel is positioned so that the slats 20 point away from the sun (i.e. slats point south) . That is, from the glazing panel the sun is in a direction which is substantially perpendicular to the planes of the slats 20. Rays from the sun falling on the glazing panel also impinge on a slat 20 because, in view of the transverse dimension of the slats 20 and their spacing, they combine to present to radiation from the sun a substantially continuous reflective surface over the entire glazing panel. For winter, the glazing panel is rotated in its own plane through 180 and thus the slats 20 point towards the sun (i.e. slats point north) . That is, from the glazing panel the sun is in a direction which is substantially parallel to the planes of the slats 20. Rays from the sun falling on the glazing panel pass through the spaces between adjacent slats. In other words, the slats 20 have negligible effect on radiation from the sun and the glazing panel transmits substantially all of the solar energy falling thereon. To illustrate the effectiveness of the glazing panel of the invention, tests were conducted for light transmission and other- solar transmission using a clear double skinned extruded acrylic skylight section with no slats and a similar skylight section having reflective polished slats positioned at an angle of 40 with respect to the planes of the sheets of the glazing panel. The results of the tests may be as follows - Light Transmission: This was measured using a uniform artificial sky, that is uniform light from all directions. (i) clear extruded section 79% (ii) panel with reflective polished aluminium slats 46% Although this shows a reduction in light transmission when using a glazing panel having polished aluminium slats, visability is hardly affected compared with using clear material because, if illumination is reduced by 60%, the capacity of the eyes to see is only reduced by approximately 6%, which is negligible. Solar Transmission: (iii) clear extruded section, no slats 76% (iv) panel with reflective alluminium slats - TABLE 1 The tests were conducted at Noon and the percentages differ as the direction of the sun in relation to the panel changed throughout the day. The results show differences due to changes in latitude and the time of the year. However, with the glazing panel positioned so that the slats point north towards the sun, there was only a very small reduction in solar transmission compared to a skylight extrusion without slats. On the other hand, with the glazing panel positioned so that the slats point south, there was a substantial reduction in solar transmission. Thus, the glazing panel of the invention may be employed effectively to permit the transmission of solar energy through a skylight during winter and be reversed during summer to reduce substantially the transmission of solar energy. In the case of a pitched roof, the skylight should be located in that part of the roof with a northerly aspect. When the glazing panel is mounted at an angle to the horizontal, the inclination of the slats 20 with respect to the sheets 12 and 14 should be adjusted to the optimum angle to reduce solar energy penetration during summer and allow maximum solar energy penetration during winter. Various modifications of the invention will be apparent to those skilled in the art. For example, the slats 20 need not be flat but may be curved. In this case all slats have the same curvature so they may be positioned in parallel relation. Instead of being polished, the reflective aluminium slats may be given a matt white finish. By selecting the correct configuration, a skylight with matt white aluminium slats can be installed so as to reduce summer solar radiation transmitted through the panel to approximately 25% of its unimpeded value. It is also possible if desired to install the skylight so as to eliminate direct * solar radiation all the year round. It is therefore clear that the invention is not to be restricted to characteristics that have been described in relation to the preferred embodiment but is to be broadly interpreted as set forth in the appended claims.

Claims: Claims : 1. A glazing panel comprising two spaced translucent substantially parallel sheets, a plurality of substantially parallel spaced reflective slats positioned between the sheets, each slat extending the length of the panel, means to space the sheets and to hold the slats in position so that they are substantially equally spaced across the width of the panel and are angularly inclined with respect to the sheets. 2. A glazing panel as claimed in claim 1 wherein said means comprises a plurality of parallel translucent ribs extending between the sheets and spaced substantially equally across the width of the panel. 3. A glazing panel as claimed in claim 2 wherein each rib extends substantially the entire length of the panel. 4. A glazing panel as claimed in claims 1, 2 or 3 wherein the sheets and the ribs are transparent and are formed from a clear plastics material. 5. A glazing panel as claimed in claim 2, 3 or 4 wherein the sheets and the ribs are formed in one piece by extrusion. 6. A glazing panel as claimed in any preceding claim wherein the sheets are planar. 7. A glazing panel as claimed in any preceding claim wherein the reflective slats are planar. MPI 8. A glazing panel as claimed in any preceding claim wherein the reflective slats are made of metal such as aluminium provided with a polished finish. 9. A glazing panel as claimed in any one of claims 1 to 7 wherein the reflective slats are made of metal such as aluminium provided with a matt white finish. 10. A glazing panel as claimed in any preceding claim wherein the angle of inclination between the slats and the sheets is 40 .

Inventors: MILLER R
Applicants: ATLITE PTY LTD, MILLER R
Application year: 1981
Main classification: E06B3
IPC codes: E06B9, F24J2