The most common form of direct solar energy usage is in heating water to provide hot water and space heating, mostly in a domestic context. Australia is in the forefront of solar hot water installations for dwellings. However, in this country and around the world, little or no use of solar energy in any form is made in relation to larger residential, commercial and industrial structures, in particular high-rise commercial and residential structures.

A solar cell is an electric cell which uses the sun's radiation to produce useable electric current. Most solar cells consist of a single-crystal silicon p-n junction.

When photons of light energy from the sun fall on or near the semiconductor junction, an electric current is created when a load is connected across the terminals of the cell. In practice, solar cells have to be assembled in arrays.

Although terrestrial use has in the past been limited by the high costs of electricity produced by solar cells, as their cost has progressively reduced over recent years, and as such cost is expected to reduce further in the future, they have become increasingly competitive, and will become even more competitive, as a source of electrical energy.

It is an object of this invention to provide an improved arrangement for using solar cells.

The invention provide a panel including first sheet means, second sheet means, and a bonding medium adapted to bond together said first sheet means and said second sheet means, said bonding medium being associated with solar cell means.

The invention also provides a building fitted with at least one panel in accordance to the preceding paragraph.

An embodiment of the invention, which may be preferred, will be described in detail hereinafter, with reference to the accompanying drawings, in which:- Fig. 1 is a cross-sectional view through part of an embodiment of a panel according to the present invention.

Most buildings have windows, glazed by glass or by an equivalent substance. The present invention envisages using such glazed areas, or parts thereof, for the installation of solar cells for the production of electricity.

Normal single-storey dwellings would not normally be suitable for such an application of solar cell technology, although skylights or other overhead windows may well be suitable. The most suitable buildings for the application of this invention are high-rise commercial buildings of the curtain wall type, where the external walls of the building are effectively almost solely constituted by glass panels.

Examples of such"curtain wall"buildings are the Corporate Centre at Corporate Court, Bundall, and 50 Cavill Avenue in Surfers Paradise, both on Queensland's Gold Coast in Australia. Those buildings present an almost unbroken façade of dark-tinted glass. In such buildings, the glass in the façade generally has only an aesthetic purpose, although the tint or reflective characteristic of window panels may reduce direct solar heating of the interiors of such buildings. However, in every other respect, for example the provision of central air conditioning, such buildings are like any other high-rise buildings.

Residential high-rise buildings are in general less suitable for the application of the present invention, because they are usually provided with balconies, which are located between windows and the sun. However, there are often windows without balconies, and many balconies have glass or equivalent panels in them rather than metal bars, and other features such as glazed atrium roofs may be suitable.

The basic concept of the present invention is to locate a solar cell, or an array of solar cells, in a panel which is used to glaze a building. More particularly, the solar

cell or solar cell array is located between two sheets which are secured together to form such a panel. More preferably, the solar cell or array of solar cells is embedded in or surrounded by a substance which bonds the two sheets together.

Turning firstly to Fig. 1, there is shown in cross-section an embodiment of a panel 10 or part thereof in accordance with the present invention. The panel 10 includes a first sheet of material 12, and a second sheet of material 16, the sheets 12,16 being arranged a generally parallel arrangement relative to one another and spaced apart as shown. Sheets 12 and 16 are bonded together by a bonding medium 18, in which a solar cell 20 is located.

The panel 10 in its simplest form, that shown in Fig. 1, may be seen as a lamination of two sheets of material (12,16) by a bonding agent 18, thus forming a laminated panel 10 of material, which includes a solar cell 20 embedded in the bonding medium 18.

By way of a preferment, sheets 12 and 16 would be glass sheets. The active side of the solar cell 20 is indicated by reference numeral 22 and it follows from that that light from the sun needs to pass through sheet 12 to reach that active side.

Accordingiy, it is desirable that sheet 12 be at worst translucent, and at best transparent, to allow maximum solar energy to reach the cell 20. It may be tinted or otherwise be one-way such that light may pass from left to right in Fig. 1, but not from right to left.

The bonding medium 18 may also be translucent, substantially transparent, or transparent, but even so it may be desirable to locate the solar cell 20 closer to the rear space between the two sheets 12,16. Provided that the bonding medium 18 secures the sheets 12,16 together, and enables the solar cell 20 to be held in place, the bonding medium 18 may be located only at certain points. For example, the medium 18 may be arranged around the edges of the sheets, which would lend itself to one of the solar cell patterns to be described hereinafter. The medium may be arranged in any pattern, and spaces left medium-free could be seen to provide a"double glazing"aspect to the panel 10. The characteristics of

sheet 16 are not of great importance, but it may be decided for aesthetic reasons that the sheet 16 be opaque.

It is apparent that a panel 10 in which is embedded a solar cell 20 or an array of solar cells 20, which occupy all or most of the area of the panel, would not be suitable for a window panel requiring a clear view therethrough. However, in the aforementioned"curtain wall"high-rise buildings, the area between floors, between, say, the base of one floor-to-ceiling window and the top of the floor-to- ceiling window on the floor below, is also glazed, but glazing panels are deliberately tinted or opaque, to hide concrete, wiring, conduits and the like. Such between floors"location would be suitable for a panel 10 carrying a full array of solar cells 20. In addition, it may be possible to glaze from the floor to the"safety bar", which is a common feature of such buildings, with a panel 10 fully occupied by an array of solar cells, leaving the portion from the bar to the ceiling for a clear view.

Furthermore, in applications, such as the aforementioned balcony panels, skylights, roof glazing panels, and even the aforementioned lower portion of a high-rise building, it may be desirable to include only a few solar cells 20, so that a partial view is obtainable. Such an array may be arranged in a pattern, to impart an aesthetic flavour to the pane) 10. Cells 20 may be arranged around the edges of the panel 10, or in any other pattern which may be desired. For skylight and glazed roof applications, the use of solar cells 20 to occupy part of a panel 10 may assisi in providing shade for the area below.

The manner in which a cell 20 or an array of cells 20 is/are wired/wired together is well known in the art. It is envisaged that the solar cell carrying panels 10 of a building would be connected to a grid in a known manner, the electricity generated by the cells 20 being fed to a central station, which may include elements such as an inverter and storage batteries, which central station in turn is able to supply electricity to a dedicated purpose in the building, such as the emergency lighting system, or into the building's general electricity system, or into the local or national electricity grid.

As has been stated, bonding medium 18 bonds sheets 12,16 together.

Preferably, the bonding medium 18 is a semi-translucent rapid cure resin material.

The thickness of the bonding medium 18 in the assembly 10 may accordingly be within the limits of the manufacturer's specifications. It may be possible, during the manufacture of a panel 10, to pour the resin liquid between sheets 12,16 at intervals, and allow it to set between each layer. The layers do not need to be parallel, as the glass fabrication may be tilted as required.

It can be seen that this invention provides a new application for solar cells technology.

The entire contents of the specification and drawing of Australian provisional patent application no. PR9339, filed on 7 December 2001, are hereby incorporated into this specification.

The claims form part of the disclosure of this specification.