AU2020207782B2

AU2020207782B2 - Cladding sheet

Info

Publication number: AU2020207782B2
Application number: AU2020207782A
Authority: AU
Inventors: Jamie ADAMS; Trevor CLAYTON; Tim ERES; Robert KLEES; Lloyd NICCOL; Sean Pickett; Brad Ryan; Anthony SKEATS; Craig WILKINSON
Original assignee: BlueScope Steel Ltd
Current assignee: BlueScope Steel Ltd
Priority date: 2014-01-07
Filing date: 2020-07-20
Publication date: 2022-03-31
Anticipated expiration: 2035-01-07
Also published as: AU2015204417A1; WO2015103666A1; AU2022204705A1; AU2018256651A1; AU2020207782A1

Abstract

Cladding sheets (9), such as roof or wall cladding sheets, include mounting sections (21) for mounting solar panels (35) on the sheets and support sections (23) for 5 supporting the mounting sections of other cladding sheets. A roof or a wall of a building formed from the cladding sheets includes air flow ducts (27) extending along the length of the cladding sheets and underlying the mounting sections in heat transfer relationship with the mounting sections for heating or cooling air flowing through the ducts. A system for generating electrical energy and thermal energy from solar energy 10 converts solar energy incident on solar panels on the roof or the wall into electrical energy and thermal energy and converts solar energy that is otherwise incident on the roof or wall into thermal energy. An integrated heating and cooling system for a building collects and transfers air that has been heated or cooled by the roof or the wall as it flows through the air flow ducts of the roof or the wall and uses the heated or 15 cooled air as a source of thermal energy in the building. 6/16 C'C Ci C) Kil Eim

Description

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CLADDING SHEET

This is a divisional application of Australian Patent Application No. 2018256651, the entire contents of which are incorporated herein by direct reference.

TECHNICAL FIELD

The present invention relates to a cladding sheet for a roof or a wall of a building. The present invention also relates to a roof or a wall of a building that is at least partly constructed from the cladding sheet. The present invention also relates to a system for generating thermal energy from solar energy that is based on the use of the cladding sheet. The present invention also relates to a system for cooling a building via a night sky cooling effect that is based on the use of the cladding sheet. The present invention also relates particularly although by no means exclusively to a solar cladding sheet assembly that includes (a) a cladding sheet and (b) a solar panel for converting solar energy into another form of energy, such as electrical energy or thermal energy, mounted on the cladding sheet. The present invention also relates to a system for generating electrical energy from solar energy that is based on the use of the use of the solar panel mounted on the cladding sheet.

BACKGROUNDART

The roof and the walls of a residential or a commercial building are large surface areas that provide opportunities for receiving and transferring energy. By way of example, the roof and the walls of a residential or a commercial building are large surface areas for mounting a solar energy conversion unit for converting solar energy into electrical energy and/or thermal energy that can be used in the building and/or a local electricity network.

The present invention is concerned with providing a cladding sheet that can form a part of a roof or a wall of a building (which terms includes residential and commercial buildings) and can provide a support for a solar energy conversion unit in the form of a solar panel. The term "cladding sheet" is understood herein to mean a sheet that is profiled to include one or more rib sections and pan sections between the rib sections, and optionally includes side edge formations that enable a plurality of the sheet to be positioned side by side in abutting or overlapping relationship. The term "cladding sheet" is also understood herein to mean sheets that can be positioned in any suitable orientation on a building. The term "cladding sheet" is also understood herein to include roof cladding sheets and wall cladding sheets. The term "solar panel" is understood herein to mean a panel that can convert solar energy into another form of energy, such as electrical or thermal energy, and can be mounted to a roof or a wall of a building. By way of example, one type of solar panel of interest to the applicant includes a photovoltaic cell module for converting solar energy into electrical energy.

SUMMARY OF THE DISCLOSURE

In broad terms, the present invention provides cladding sheets, such as roof or wall cladding sheets, that are configured to be positioned in side by side overlapping relationship with one another and that include mounting sections for mounting solar panels on the sheets and support sections for supporting the mounting sections of other cladding sheets in side by side overlapping relationship. The mounting sections comprise flat surfaces to provide surface areas of contact between the solar panels and the mounting sections. The support sections are formed to define with the mounting sections of other cladding sheets in side by side overlapping relationship one or more air flow duct(s) provided underlying each of the mounting sections in heat transfer relationship with the mounting sections for heating or cooling air flow through the duct(s). The invention separates the quite different functions for cladding sheets for mounting solar panels, namely the function of providing mounting sections for securely mounting solar panels to the cladding sheets and the function of supporting the mounting sections so that the cladding sheets meets the structural requirements for the cladding sheets. The invention optimizes these separate functions in different sections of the one cladding sheet. In accordance with the invention, the cladding sheets may include a mounting section and a support section as part of the one sheet. By way of example, the cladding sheets may be formed so that the support section of one cladding sheet underlies and supports the mounting section of a successive cladding sheet. The description of the invention focuses on cladding sheets of this type. In this context, the present invention provides a cladding sheet, such as a roof or a wall cladding sheet, that is configured to be positioned in side by side overlapping relationship with another said cladding sheet and that includes a mounting section for mounting a solar panel on the sheet and a support section for supporting the mounting section of another cladding sheet in side by side overlapping relationship. The mounting section comprises a flat surface to provide a surface area of contact between the solar panel and the mounting section. The support section is formed to define with the mounting section of the other cladding sheet one or more than one air flow duct underlying the mounting section in heat transfer relationship with the mounting section for heating or cooling air flow through the duct(s). In use, in an assembled wall or roof, the support section of one cladding sheet underlies and supports the mounting section of another cladding sheet. This arrangement makes it possible to support the mounting sections of cladding sheets properly. This arrangement also makes it possible to provide a substantially continuous mounting surface, such that a roof or a wall may include a substantially continuous arrangement of solar panels, thereby maximising the available surface area for collecting solar energy, within a selected area of a roof or a wall or over the whole surface of the roof or the wall. The cladding sheet may include the solar panel mounted to the mounting section of the sheet. In other words, the invention extends to (a) a cladding sheet per se and (b) a solar cladding sheet assembly that includes a cladding sheet and a solar panel mounted to the cladding sheet.

The cladding sheet may be formed so that, in use, the mounting sections of successive cladding sheets in the roof or the wall are in the same plane. The support section and the mounting section may be formed to define the one or more than one elongate duct extending along the length of the cladding sheets underlying the mounting section when two successive sheets are positioned in side by side overlapping relationship to form the part of the roof or the wall, with each duct having an inlet at one end and an outlet at the other end for air flow along the length of the ducts. Each duct may be a closed duct along the length of the duct at the overlap between a support section of one cladding sheet and the mounting section of the successive cladding sheet. In this context, the term "closed" means that there is no air flow into or out of the duct other than via the inlet and the outlet at the ends of the duct. Each air flow duct provides an opportunity for heat transfer from the cladding sheet and the solar panel (when present) to air flowing through the duct. The heat transfer may be from the cladding sheet and the solar panel (when present) to the air flowing through the duct. The heat transfer may be from the air flowing through the duct to the cladding sheet and the solar panel (when present). The heat transfer may heat or cool the air flowing through the duct. For example, in situations where there is a solar panel on the cladding sheet and the solar panel includes a photovoltaic cell module, cooling the solar panel via heat transfer to air flowing through the duct may be an important issue from the viewpoint of performance. Specifically, the efficiency and operating life of photovoltaic cells decreases with temperature increase and hence heat removal is an important consideration for maintaining high efficiency operation and optimum operating life of the solar panel. Moreover, the heated air produced as a consequence of the heat transfer provides an opportunity to provide thermal energy for use in the building to improve energy efficiency in the building. By way of further example, at night time, there is also an opportunity for air flowing through each duct to be cooled below ambient temperature in a process referred to as night sky cooling. The cladding sheet (and the solar panel when present) are in thermal contact with the surrounding atmosphere. On nights when there is limited cloud coverage, the cladding sheet (and the solar panel) radiate heat to the atmosphere.

Typically, this heat transfer via radiation can reduce the temperature of the solar panel (when present) by around 5-10°C below the ambient temperature. The air flowing through the duct, which is at the ambient temperature at an inlet of the duct, can transfer heat to the cladding sheet (and the solar panel), thereby reducing the temperature of the air flow through the duct. This cooled air can be used in the building to improve energy efficiency beyond what would normally occur with ambient air flowing from the building at night. The cladding sheet may include other ducts extending along the length of the cladding sheet underlying the mounting section when two successive sheets are positioned in side by side overlapping relationship to form the part of the roof or the wall which are not intended for air flow but are provided for housing other devices, such as devices associated with transferring electrical energy produced by the solar panel to an electrical system of the building or a local electrical network, such as cabling, transformers, maximum power point tracking, and inverters, converters, etc. or for the channeling of rain water to a gutter in the case of roof cladding sheets. The cladding sheet may define a water gutter between adjacent mounting sections when two successive sheets are positioned in side by side overlapping relationship to form the part of the roof or the wall. The support section and the mounting section may be the same width. The support section and the mounting section may be different widths. The support section may be a profiled section that provides rigidity for the sheet. The support section may include one or more parallel rib sections and pan sections between the rib sections. The support section may include any suitable number of rib sections and pan sections. The mounting section may be a flat surface for mounting the solar panel. The widths of the pan sections may be substantially larger than the widths of the rib sections. The widths of the pan sections may be at least twice the widths of the rib sections. The rib sections may have flat tops to provide a stable platform for supporting a mounting section of a successive roof cladding sheet.

The tops of the rib sections and the flat surface of the mounting section may be substantially in the same plane. The heights of the tops of the rib sections above a base plane of the roof cladding sheet may be the thickness of the sheet of the roof cladding sheet less than the height of the flat surface of the mounting section above the base plane so that, in use, successive mounting sections are in the same plane across the roof. The solar panel may be any suitable panel. The solar panel may be used for transfer of thermal energy only. The solar panel may include (a) a photovoltaic cell module for converting solar energy into electrical energy and (b) electrical components, such as a wiring junction box and electrical cables and other devices for transferring electrical energy from the solar panel for use in an electrical system of the building or a local electrical network. The solar panel may be in the form of a flexible film. The photovoltaic cell module may include a semi-conductor material electro deposited or otherwise deposited on an electrically-conductive, such as stainless steel, flexible substrate and encapsulated in a moisture barrier laminate material. The photovoltaic cell module may include organic photovoltaic material encapsulated in a moisture barrier laminate material. The photovoltaic cell module may include organic or semi-conductor material directly applied/deposited on the profiled sheet and encapsulated in a moisture barrier laminate material. The cladding sheet may include side edge formations that enable successive sheets to be positioned side by side in overlapping relationship. The cladding sheet may include end edge formations that enable successive sheets to be positioned in end to end overlapping relationship. The cladding sheet may be any suitable length and any suitable width. The cladding sheet may be a steel sheet. The cladding sheet may be roll-formed or pressed or otherwise formed from sheet steel and optionally includes a painted outer coating. The cladding sheet may be formed from extruded aluminium or plastics material. The cladding sheet may be formed from any other suitable material.

The present invention also provides a roof or a wall that includes a plurality of cladding sheets, with the cladding sheets positioned in side by side overlapping relationship with one another and including mounting sections for mounting solar panels on the sheets and support sections for supporting the mounting sections of other cladding sheets in side by side overlapping relationship. The mounting sections comprise flat surfaces to provide surface areas of contact between the solar panels and the mounting sections. The support sections are formed to define with the mounting sections of other cladding sheets in side by side overlapping relationship one or more air flow duct(s) provided underlying each of the mounting sections in heat transfer relationship with the mounting sections for heating or cooling air flow through the duct(s). The cladding sheets may include a mounting section and a support section as part of the one sheet. The roof or the wall may include a plurality of solar panels mounted to mounting sections of at least some of the cladding sheets. The mounting sections may form a substantial part, typically at least 90%, of the surface area of the roof or the wall. Each solar panel may include (a) a photovoltaic cell module for converting solar energy into electrical energy and (b) electrical components, such as a wiring junction box and electrical cables and other devices, for transferring electrical energy from the solar panel for use in an electrical system of the building or a local electrical network. The cladding sheets may extend at any angle to a ridge line of the roof or to an upper edge of the wall. The cladding sheets may be arranged to extend horizontally across the roof or the wall, such that the longitudinal axes of the sheets are parallel to the ridge of the roof or the upper edge and a lower edge of the wall. The cladding sheets may be arranged to extend down the roof or the wall. With this arrangement, the longitudinal axes of the sheets may extend down the roof between a ridge and a gutter of the roof or down the wall from an upper edge to a lower edge of the wall. The roof may include a gutter for water run-off extending down the roof between adjacent roof cladding sheets. With this arrangement, the exposed surface of the roof includes a series of parallel mounting sections of the cladding sheets (optionally with solar roof panels on the mounting sections) and a series of parallel gutters. With this arrangement, typically the mounting sections form a substantial part, typically at least 90%, of the surface area of the roof. The design of the cladding sheets makes it possible to manufacture custom-sized roof cladding sheets that address a variety of ridge, hip, gutter and roof styles. Similarly, the design of the cladding sheets makes it possible to manufacture custom-sized wall cladding sheets that address a variety of wall styles. The cladding sheets may be the above-described cladding sheet, whereby in the roof or the wall the support section of one cladding sheet underlies and supports the mounting section of a successive cladding sheet. The support section of one cladding sheet and the mounting section of another mounting section may define one or more than one elongate air flow duct extending along the length of the cladding sheets underlying and in direct heat transfer relationship with the mounting section. The direct heat transfer area may be at least 60%, typically at least 70%, and more typically at least 80%, of the area of the mounting section. Each duct may have an inlet at one end and an outlet at the other end for air flow along the length of the ducts. The ends of each duct may be open. Alternatively, the ends of each duct may be closed and there may be holes in end sections of the cladding sheets that allow air to pass into and from the ducts. Each duct may be a closed duct as described above along the length of the duct at the overlap between a support section of one cladding sheet and the mounting section of the successive cladding sheet. Each duct may be any suitable transverse cross-sectional area. Typically, each duct has a transverse width to height ratio of at least 1:1, more typically at least 1.5:1. The roof may include cladding sheets that extend the whole distance between the ridge and the gutter of the roof. The roof may include a plenum chamber that extends along the ridge of the roof for collecting air flow from the outlets of the ducts.

The plenum chamber may include an outlet for transferring the air from the chamber to an end use application. The plenum chamber may form part of an air distribution network for collecting and transferring air that has been heated or cooled by the above-described roof or the wall as it flows through the air flow ducts of the roof or the wall for use as a source of thermal energy in the building or elsewhere, for example for heating or cooling a swimming pool or any other suitable end use application. The roof may include two or more than two rows of roof cladding sheets in side by side relationship across the roof, with the cladding sheets in each row extending a part of the distance between the ridge and the gutter of the roof. The cladding sheets in successive rows from the ridge to the gutter may be aligned in end to end relationship. The lower end sections of the cladding sheets in an upper row may extend at least partly over and thereby overlap the upper end sections of the cladding sheets in a lower row. The overlap is useful by way of example for water run-off. The roof may include a flashing element that forms a weather seal at the overlap between successive rows of cladding sheets. The roof may include a plenum chamber that extends along the ridge of the roof for collecting air flow from the outlets of the ducts that are in the row that ends at the ridge. The roof may include a plenum chamber associated with each lower row of cladding sheets, with the plenum chamber extending across the roof for collecting air flow from the outlets of the ducts in the lower row of cladding sheets. Each plenum chamber may include an outlet for transferring the air from the chamber to an end use application. Each plenum chamber may form part of the above-described air distribution network. The roof may include an electrical connection between the solar panels on the cladding sheets in successive rows of cladding sheets. The roof or the wall may include a weather seal, such as a foam seal, along the length of the duct at the overlap between a support section of one cladding sheet and the mounting section of the successive cladding sheet. The weather seal may be an air/water seal. As indicated above, the air flow in the ducts provides an opportunity to cool the solar panels via heat transfer from the panels to air that flows through the ducts. The efficiency and operating life of photovoltaic cells decreases with temperature increase and hence heat removal is an important consideration for maintaining high efficiency operation and optimum operating life of the solar panels. Moreover, the heated air provides an opportunity to provide thermal energy for use in the building to improve energy efficiency in the building or to use the thermal energy in other applications, such as for heating a swimming pool. In addition, as indicated above, the air flow in the ducts provides an opportunity to cool air flowing through the ducts to be below ambient temperature via night sky cooling, with the cooled air being available to be used in the building to improve energy efficiency beyond what would normally occurring with ambient air flushing from the building at night or for use in other applications. The roof or the wall also includes a system to minimise the ingress of air borne impurities and vermin into the ducts. The system may be in the form of mesh positioned at the inlet of a duct. The system may be any suitable type of air filter. The roof may be a pitched roof or a flat roof. Typically, a minimum pitch of 3 5° is necessary to allow water to drain properly from the roof. The present invention also provides a roof or a wall of a building that includes a plurality of steel cladding sheets mounted in side by side overlapping relationship that define (a) mounting sections for solar panels, the mounting sections comprising flat surfaces to provide surface areas of contact between the solar panels and the mounting sections, (b) support sections for supporting the mounting sections of other steel cladding sheets, and (c) air flow ducts underlying the mounting sections in heat transfer relationship with the mounting sections for heating or cooling air flowing through the ducts, the air flow ducts being defined by the mounting sections and support sections of cladding sheets in side by side overlapping relationship and with the ducts having inlets at one end of the ducts and outlets at the other ends of the ducts. The cladding sheets may include support sections for supporting the mounting sections, as described above.

The roof or the wall may include a plenum chamber for collecting air flow from the outlets of the air flow ducts. The plenum chamber may include an outlet for transferring the air from the chamber to an end use application. The present invention also provides a system for generating electrical energy from solar energy that includes converting solar energy that is incident on solar panels on the above-described roof or wall into electrical energy. The system may include an inverter system or a converter system capable of transferring electrical energy to an electrical system of the building or a local electrical network. The present invention also provides a system for generating electrical energy and thermal energy from solar energy that includes converting solar energy that is incident on solar panels on the above-described roof or wall into electrical energy and thermal energy and converting solar energy that is otherwise incident on the roof or wall into thermal energy. The system may include an inverter system or a converter system capable of transferring electrical energy to an electrical system of the building or a local electrical network. The system also includes an air distribution network for collecting and transferring air that has been heated or cooled by the above-described roof or the wall as it flows through the air flow ducts of the roof or the wall for use as a source of thermal energy in the building or elsewhere, for example for heating or cooling a swimming pool or any other suitable end use application. The air distribution network may be arranged for collecting and transferring heated or cooled air from the outlet ends of the ducts of the roof to the building for direct space heating or cooling of the building. The air distribution network may include (a) a plenum chamber in the roof space that is connected to and receives heated or cooled air from the outlet ends of the ducts in the roof and (b) a duct for transferring heated or cooled air to the building. The air distribution network may include a fan for causing air flow into and from the plenum chamber and through the duct for transferring heated or cooled air to the building.

The roof or the wall may include a seal, such as a foam seal, along the length of the plenum chamber for weather and air tightness. This seal may be an air/water seal. The system may be a part of an integrated heating and cooling system for the building. The invention also provides an integrated heating and cooling system for a building which includes the above-described system for collecting and transferring air that has been heated or cooled by the above-described roof or the wall as it flows through the air flow ducts of the roof or the wall for use as a source of thermal energy in the building. The integrated heating and cooling system for the building may include other sources of thermal energy for heating and cooling in the building. The other sources may include electricity powered heating or cooling systems and gas-fired heating systems. The integrated heating and cooling system for the building may be operatable by way of example to minimise system operating costs for a building owner. The integrated heating and cooling system for the building may include a controller that senses the energy requirements for the building and operates the roof system as required to meet the energy requirements. The integrated heating and cooling system for the building may include internal and external sensors for providing data to the controller. The sensors may include a sensor for sensing the temperature of the roof cladding sheets. The system may include an air distribution network for collecting and transferring heated or cooled air from the outlet ends of the ducts of the roof for use in other applications, such as by indirect approaches such as storing the thermal energy in phase change materials. Another, although by no means the only other application for heated air is in dryer systems in buildings. Other applications include transferring the thermal energy into other suitable media, such as water, which can then be used by way of example only for heating hot water systems for buildings, swimming pools and other equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described further, by way of example only, with reference to the accompanying drawings of which: Figure 1 is a perspective view of a section of a roof of a building with a plurality of roof cladding sheets in accordance with one embodiment of the invention mounted to the roof and a plurality of solar roof panels in accordance with one embodiment of the invention mounted to the roof cladding sheets, with the roof cladding sheets being arranged to run down the roof, i.e. so that the air flow ducts of the roof cladding sheets run from a gutter line to a ridge line; Figure 2 is a perspective view of a section of a partially-constructed roof of another building with a plurality of roof cladding sheets in accordance with one embodiment of the invention mounted to the roof and a plurality of solar roof panels in accordance with one embodiment of the invention mounted to the roof cladding sheets, with the roof cladding sheets being arranged to run down the roof from a ridge to a gutter, i.e. so that the air flow ducts of the roof cladding sheets run from a gutter line to a ridge line; Figure 3 is a perspective view of the section of the partially-constructed roof shown in Figure 2 from a different angle to that of Figure 2; Figure 4 is a side elevation of the section of the partially-constructed roof shown in Figures 2 and 3; Figure 5 is a perspective view of three roof cladding sheets used in the construction of the section of the partially-constructed roof shown in Figures 2 to 4 in side by side overlapping relationship; Figure 6 is a perspective view of the three roof cladding sheets shown in Figure 5 from a different angle to that of Figure 5; Figure 7 is an end view of the three roof cladding sheets shown in Figures 5 and 6; Figure 8 is an end view of one of the three roof cladding sheets shown in Figures 5 to 7; Figure 9 is a perspective view of one of the three roof cladding sheets shown in Figures 5 to 7;

Figure 10 is a perspective view is of a section of a partially-constructed roof of another building similar to that shown in Figure 1 with a plurality of roof cladding sheets in accordance with the embodiment of the invention shown in Figures 1 to 9 mounted to the roof but without a plurality of solar roof panels mounted to the roof cladding sheets, with the roof cladding sheets being arranged to run down the roof from a ridge to a gutter, i.e. so that the air flow ducts of the roof cladding sheets run from a gutter line to a ridge line; Figure 11 is an enlarged perspective view of a section of the roof shown in Figure 10; Figure 12 is a perspective view of another embodiment of a roof cladding sheet in accordance with the invention; Figure 13 is an end view of the view of the roof cladding sheet shown in Figure 12; Figure 14 is an end view of two of the roof cladding sheet shown in Figures 12 and 13 is side by side overlapping relationship; Figure 15 is a perspective view of another embodiment of a roof cladding sheet in accordance with the invention; Figure 16 is an end view of the view of the roof cladding sheet shown in Figure 15; Figure 17 is an end view of two of the roof cladding sheet shown in Figures 15 and 16 is side by side overlapping relationship; Figure 18 is a perspective view is of a section of a partially-constructed roof of another building with a plurality of roof cladding sheets in accordance with the embodiment of the invention shown in Figures 1 to 9 mounted to the roof, with the roof cladding sheets being arranged to run down the roof from a ridge to a gutter, i.e. so that the air flow ducts of the roof cladding sheets run from a gutter line to a ridge line; Figure 19 is a side elevation of the section of the partially-constructed roof shown in Figure 18; Figure 20 is an enlargement of the circled region "A" of the roof shown in Figure 20; Figure 21 is an enlargement of a part of the roof shown in Figure 18;

Figure 22 is perspective view of a section of a roof of a building with a plurality of roof cladding sheets in accordance with one embodiment of the invention mounted to the roof and a plurality of solar roof panels in accordance with one embodiment of the invention mounted to the roof cladding sheets, with the roof cladding sheets being arranged to run across the roof, i.e. parallel to a ridge line and a gutter of the roof; Figure 23 is a perspective view of two roof cladding sheets in accordance with one embodiment of the invention in side by side overlapping relationship, with the embodiment adapted to be arranged so that the sheets run across the roof, i.e. parallel to a ridge line of the roof as shown in Figure 22; Figure 24 is a cross-section of the two roof cladding sheets shown in Figure 23; and Figure 25 is a perspective view of a section of a roof of a building with a plurality of solar roof panels in accordance with one embodiment of the invention mounted to the roof of a commercial or industrial building with the air flow ducts running from the eaves to a ridge line.

DESCRIPTION OF EMBODIMENTS

The following description of embodiments of the invention focus on cladding sheets in the form of roof cladding sheets. This is an application of the invention that is of particular interest to the applicant. However, it is noted that the invention is not confined to this application and extends to other applications such as wall cladding sheets. In general terms, the invention separates the quite different functions for cladding sheets of providing mounting sections for solar panels and supporting the mounting sections and optimizes the separate functions in different sections of (a) the one cladding sheet or (b) in separate cladding sheets. The embodiments of the roof cladding sheet of the present invention shown in the Figures are formed from sheet steel and include a mounting section for mounting a solar roof panel on the roof cladding sheet and a support section for supporting the mounting section of a successive roof cladding sheet that is positioned in side by side overlapping relationship to form a part of a roof, with the mounting section and the support section being parts of one sheet. The embodiments of the roof of the present invention shown in the Figures include a plurality of the roof cladding sheets shown in the Figures mounted in side by side overlapping relationship with the support section of one sheet underlying and supporting the mounting section of a successive sheet. This arrangement makes it possible to support the mounting sections of roof cladding sheets properly. This arrangement also makes it possible to provide a substantially continuous mounting surface, such that a roof may include a substantially continuous arrangement of solar roof panels, thereby maximising the available surface area for collecting solar energy. It is noted that the present invention also extends to embodiments in which there are roof cladding sheets that have a mounting section only and roof cladding sheets that have a support section only. With these embodiments, in use, the roof cladding sheets that have support sections only underlie and support the roof cladding sheets that have mounting sections only. In the Figures, the cladding sheets 9, such as roof or wall cladding sheets, include mounting sections 21 for mounting solar panels 35 on the cladding sheets 9 and support sections 23 for supporting the mounting sections of other cladding sheets 9. In addition, a roof or a wall of a building formed from the cladding sheets 9 includes air flow ducts 27 extending along the length of the cladding sheets 9 and underlying the mounting sections 21 in heat transfer relationship with the mounting sections 21 for heating or cooling air flowing through the ducts 27. In addition, a system for generating electrical energy and thermal energy from solar energy converts solar energy incident on solar panels 35 on the roof or the wall into electrical energy and thermal energy and converts solar energy that is otherwise incident on the roof or wall into thermal energy. In addition, an integrated heating and cooling system for a building collects and transfers air that has been heated or cooled by the roof or the wall as it flows through the air flow ducts of the roof or the wall and uses the heated or cooled air as a source of thermal energy in the building. The integrated heating and cooling system for the 3o building may include other sources of thermal energy for heating and cooling the building, with the system being operated by way of example to minimise system operating costs for a building owner.

There are a large number of different embodiments of the roof cladding sheet of the invention and the roof of the invention. The embodiments include the following features. • Embodiments of the roof cladding sheet that are suitable for residential applications. • Embodiments of the roof cladding sheet that are suitable for commercial applications. • Embodiments of the roof cladding sheet that are suitable for residential and commercial applications. Embodiments of the roof cladding sheet that are suitable for converting solar energy into electrical energy. • Embodiments of the roof cladding sheet that are suitable for converting solar energy into thermal energy. • Embodiments of the roof cladding sheet that are suitable for converting solar energy into electrical energy and thermal energy. • Embodiments of the roof cladding sheet that are suitable for cooling outdoor air utilising night sky cooling. • Embodiments of the roof cladding sheet that are suitable to extend across a roof - i.e. "horizontal" options. • Embodiments of the roof cladding sheet that are suitable to extend down a roof between a ridge and a gutter of the roof- i.e. "vertical" options. * Embodiments of the roof cladding sheet that are suitable for use on a range of different roof types, including hip, gable and skillion roofs. Figure 1 illustrates an embodiment of a hip roof in accordance with the invention. The hip roof is conventional insofar as it comprises a ridge 5, a number of inclined sides 11, and perimeter gutters 7. The roof is made from a plurality of one embodiment of a roof cladding sheet 9 (see Figures 2 to 9) in accordance with the invention mounted in side by side overlapping relationship to an underlying roof frame (not shown in Figure 1) and a plurality of solar roof panels 35 mounted to a number of the roof cladding sheets 9.

The roof cladding sheets 9 are arranged so that the longitudinal axes of the sheets extend down the roof sides from the ridge 5 to the gutters 7. The roof cladding sheets 9 may be mounted to the roof frame by any suitable means, such as fasteners, adhesives and concealed clips. A section 17 of each of the sides 11 shown in Figure 1 includes a plurality of the solar roof panels 35 mounted to the roof cladding sheets in these sections 11 and forming a substantially continuous coverage in those sections 17. Typically the solar roof panels 35 are in the form of thin films of photovoltaic (PV) cells. Figures 2 and 3 are perspective views and Figure 4 is a side view of a section of a partially-constructed roof of a building with a plurality of roof cladding sheets 9 in accordance with one embodiment of the invention mounted to a roof frame generally identified by the numeral 71, typically a timber or steel frame, to form the roof and a plurality of solar roof panels 35 in accordance with one embodiment of the invention mounted to the roof cladding sheets. The roof cladding sheets 9 are arranged to run down the roof from the ridge 5 to the gutter 7, i.e. so that air flow ducts 27 that are formed by the roof cladding sheets 9 and are described further below run from a gutter line to a ridge line. The partial construction shown in the Figures reveals the location of the roof cladding sheets 9 on the underlying roof frame 71. It is evident from Figures 1 to 3 that the area the solar roof panels 35 occupy is a substantial part of the sections 17 of the roof on which they are mounted. It is noted that the area may be any suitable area. The invention is not confined to the particular solar roof panels 35 shown in Figure 1 and in Figures 2 to 4. The invention is also not limited to the particular arrangements of the sections 17 of the solar roof panels 35 on the roofs. Specifically, the roofs shown in Figure 1 and Figures 2 to 4 are by way of illustration only and the invention is not confined to hip roofs shown in the Figures and to the specific numbers and arrangements of roof cladding sheets 9 on the roofs. The arrows in Figures 2 to 4 indicate the direction of water flow over the roof cladding sheets 9 and thereby provide a frame of reference for the orientation of the sheets in these Figures (as well as in Figure 1).

Figures 5 to 7 show three of the roof cladding sheets 9 of the roof shown in Figures 2 to 4 in side by side overlapping relationship. Figures 8 and 9 are end and perspective views of one of the three roof cladding sheets 9. The roof cladding sheets 9 shown in Figures 5 to 9 are formed by roll forming or pressing from sheet steel. With reference to Figures 5-9, each roof cladding sheet 9 includes a mounting section 21 for mounting a solar roof panel 35 on the roof cladding sheet 9 and a support section 23 for supporting the mounting section 21 of a successive roof cladding sheet 9 that is positioned in side by side overlapping relationship to form a part of the roof. As can be seen in the Figures, the support sections 23 underlie and support the mounting sections 21. The width of the mounting section 21 and width of the support section 23 are substantially the same. The roof cladding sheet 9 separates the quite different functions for cladding sheets for mounting solar roof panels 35, namely the function of providing mounting sections for securely mounting solar roof panels to the cladding sheets and the function of supporting the mounting sections so that the cladding sheets meets the structural requirements for the cladding sheets. The roof cladding sheet 9 optimizes these separate functions in different sections of the one cladding sheet. The roof cladding sheets 9 are held together in overlapping relationship via fasteners (not shown) but could also be held together in overlapping relationship by any other suitable options, including concealed clips. The support sections 23 and the mounting sections 21 are substantially the same width. Each mounting section 21 is a flat surface to maximise the surface area of contact between a solar roof panel and the mounting section 21. The mounting sections 21 form a substantial part, typically at least 85%, and more typically at least 90%, of the surface area of the exposed upper surface of the roof. Each support section 23 is a profiled section that provides rigidity for the roof cladding sheet 9. Each profiled section comprises parallel rib sections 29 and pan sections 31 between the ribs 29. The width of the pan sections 31 is substantially larger than, typically at least twice, the width of the rib sections 29. The rib sections 29 may have flat tops 73 to provide a stable platform for supporting a mounting section 21 of a successive roof cladding sheet 9. The rib sections 29 may be any suitable profile.

The tops 73 of the rib sections 29 and the flat surface of the mounting section 23 are substantially in the same plane. More specifically, the heights of the tops 73 of the rib sections 29 above a base plane of the roof cladding sheet 9 is the thickness of the sheet steel of the roof cladding sheets 9 less than the height of the flat surface of the mounting section 23 above the base plane so that successive mounting sections 23 are in the same plane across the roof. Successive roof cladding sheets 9 define a plurality of elongate ducts 27 extending along the length of the roof cladding sheets 9. The ducts 27 are formed at the overlap between a support section 23 of one roof cladding sheet 9 and the mounting section 21 of the successive panel 9. More specifically, the ducts 27 are positioned beneath the mounting sections 21 of the roof cladding sheets 9. It is evident from Figures 2 to 7 that the ducts 27 are in direct thermal contact, i.e. heat transfer relationship, with a substantial part of the mounting section 21 of each roof cladding sheet 9 in the roof. As is described further below, the ducts 27 facilitate heat transfer from the mounting sections 21 (and the solar panels 35) to air flowing in the ducts 27. Each duct 27 has an inlet at one end and an outlet at the other end for air flow along the length of the ducts. The ducts 27 are closed along the length of the ducts so that there is no air flow into or out of the ducts 27 other than via the inlets and the outlets at the ends of the ducts. In the embodiments shown in Figure 1 and in Figures 2 to 4, the air flow is upwardly inclined air flow via from the gutters 7 to the ridge 5 of the sides of the roof. The outlets of the ducts 27 open into and therefore can supply air into a roof space of the roof or into a plenum chamber (see Figures 10 and 11 and described further in relation to these Figures) in the roof space. The roof includes duct work (not shown) that delivers the air to rooms in the building (or elsewhere as required - by way of example to a dryer (not shown)). With particular reference to Figures 8 and 9, the roof cladding sheet 9 also includes an elongate channel 41 that extends along the length of the roof cladding sheet 9. The channel 41 is formed to carry water to the gutter 7 in an assembled roof. As can 3o be seen in Figures 5 to 7, in an assembled roof, the channels 41 form a plurality of parallel gutters 75 in the section of the roof shown in the Figures that separate adjacent mounting sections 21.

It is apparent from Figures 5 to 7 that the exposed surface of the roof includes a series of parallel mounting sections 21 of the cladding sheets 9 and a series of parallel gutters 75. With this arrangement, typically the mounting sections form a substantial part, typically at least 90%, of the surface area of the roof. With further reference to Figures 5 to 9, each roof cladding sheet 9 is also formed to facilitate locating a plurality of the sheets 9 in side by side overlapping relationship. This is achieved by forming the side wall of the rib 29 that is adjacent the mounting section 21 with a laterally extending formation 45 and the side of the cladding sheet 9 that is adjacent the mounting section 21 with an inturned lip 43 that is shaped to fit over the formation 45. The arrangement is such that when a new cladding sheet 9 is being positioned onto an existing cladding sheet 9 on a roof, the inturned lip 43 is positioned to extend over the formation 45, with the mounting section 21 of the new cladding sheet 9 being positioned on and supported by the support section 23 of the existing cladding sheet 9. Therefore, the inturned lip 43 and the formation 45 facilitate locating the roof cladding sheets 9 onto a support frame. The direction of laying successive cladding sheets 9 on a roof is indicated by the arrow in Figure 7. Figures 10 and 11 are perspective views is of a section of a partially-constructed roof of another building similar to that shown in Figure 1 with a plurality of roof cladding sheets 9 in accordance with the Figures 1 to 9 embodiment mounted to the roof but without a plurality of solar panels 35 mounted to the roof cladding sheets 9. Typically, the roof will include solar panels 35. As is the case with Figure 1 to 9, the roof cladding sheets 9 are arranged to run down the roof from a ridge 5 to a gutter (not shown)., i.e. so that the air flow ducts 27 of the roof cladding sheets 9 run from a gutter line to a ridge line. Figures 10 and 11 show that the outlets of the ducts 27 open into and therefore can supply air into a plenum chamber 77 that is located in the roof space and extends along the ridge 5 of the roof shown in the Figures. The plenum chamber 77 is defined by elongate folded sheet steel elements that define a lower part of the plenum chamber 77 and an elongate ridge cap (not shown) that defines an upper part of the plenum chamber 77. The sides of the plenum chamber 77 are defined by the outlets of the ducts 27 and elongate weather strips 85, 87 that close the otherwise open ends of the cladding sheets 9. The ends of the plenum chamber 77 are defined by weather seals 89. Duct work (not shown) delivers the air to rooms in the building (or elsewhere as required by way of example to a dryer (not shown)) via outlets 79 in the plenum chamber. The plenum chamber 77 forms part of an air distribution network for collecting and transferring air that has been heated or cooled by the roof as it flows through the ducts 27 for use as a source of thermal energy in the building or elsewhere, for example for heating or cooling a swimming pool or any other suitable end use application. This may be any suitable air distribution network. The air flow through the ducts 27 in the roof into the building provides an opportunity to cool the solar roof panels 35 via heat transfer from the panels 17 and the mounting sections 21 of the roof cladding sheets 9 to air that flows through the ducts 27. The efficiency and operating life of photovoltaic cells decreases with temperature increase and hence heat removal is an important consideration for maintaining high efficiency operation and optimum operating life of the solar panels 35. Moreover, heated air in the ducts 27 via the above-described heat transfer provides an opportunity to provide thermal energy for use in the building to improve energy efficiency in the building or in other end use applications. In addition, at night, the roof can cool air flowing through the ducts 27 below ambient temperature and the cooled air can then be used in the building to improve energy efficiency. As described above, night sky cooling occurs particularly on nights when there is limited cloud coverage, and is the result of the solar panels 35 and the cladding sheets 9 radiating heat to the atmosphere. Typically, this heat transfer via radiation can reduce the temperature of the solar panels 35 by around 5-10°C below the ambient temperature. The air flowing through the ducts 27, which is at the ambient temperature at the inlets of the duct 27, can transfer heat to the solar panels 35 and the cladding sheets 9, thereby reducing the temperature of the air flow through the ducts 27. This cooled air can be used in the building to improve energy efficiency beyond what would normally occur with ambient air flowing from the building at night. Figures 12 to 14 and Figures 15 to 17 show two other embodiments of the roof cladding sheet 9 in accordance with the invention. The same reference numerals are used to describe the same structural features in Figures 12 to 17 that are used in Figures Ito 11. The two embodiments of the roof cladding sheet 9 are very similar to each other and to the embodiment shown in Figures 1 to 9. One difference is the heights of the ribs 29 of the three embodiments. Another difference is that the Figures 12 to 17 embodiments have less complicated formations on the sides of the cladding sheets 9 to facilitate locating successive roof cladding sheets 9 in side by side overlapping relationship, as shown in Figures 14 and 17. The Figures 12 to 17 embodiments are secured to the roof frame by means of roof fasteners (not shown). Typical dimensions for the roof cladding sheet 9 are as follows: • At least 0.5 m, typically at least 1.5 m, and more typically at least 2 m. A typical range for roof cladding sheets is 1.5-15 m, although it is noted that the invention extends to longer and shorted length sheets. Sheet feed width - > 900 mm, typically 940 mm and 1200 mm. • Duct size - 8-100mm deep. • Width to height ratio of duct - > 1:1 - typically > 2:1. • Mounting section width - > 350 mm • Steel sheet thickness - > 0.4 mm, typically 0.42 mm and 0.48 mm. Optimised to minimise cost of roof and meet structural requirements The following is a non-exhaustive list of considerations when designing the profile of the roof cladding sheet 9.

Structural The cladding sheets 9 have to be rigid enough to meet the loading requirements specified in building standards. In the case of the Australian Standards, the loading requirements are a point load to simulate the fixers or maintenance people walking on the roof and wind loading. The profile needs to be able to be walked on without any permanent damage. The roof cladding sheets 9 also have to be able to withstand wind loading, which is usually an uplift load. The parameters that influence structural rigidity are metal thickness, rib height and shape, number of ribs, support spacing, and number of fasteners and their size/withdrawal strength.

Materials A decision needs to be made on what material will be used for the roof cladding sheet 9 as this affects some of the design parameters. The options to be considered are: • Thickness. Increased thickness gives increased strength but makes the

material harder to cut by hand and harder to manhandle due to the increased weight. • Steel Grade: As required having regard to structural and cost and other relevant considerations. • Corrosion resistance of material. • Aesthetic appeal.

Feed width The most common feed width used in Australia for roofs and walls is 940 mm. Another common feed width in Australia is 1200 mm. Other countries may have different sizes.

Cladding sheet width Wider cladding sheet width potentially makes the roof installation quicker but also makes it harder to man handle the roof cladding sheet 9.

Solar roof panel size The mounting section 21 of the roof cladding sheet 9 is typically a wide flat pan to allow the adhesion of a solar roof panel 35 in the form of a thin film of photovoltaic (PV) cells. Thin film PV panels include, by way of example: • Unisolar amorphous silicon.panel • SoloPower (CIGS) panel. • Solarium (CIGS) panel. • Global Solar (CIGS) panel The minimum length of these thin film PV panels is typically about 2 m. The invention extends to other types of solar roof panels 35.

PV Packing Factor The pan section and cover width of the roof cladding sheet 9 affects the packing factor of the PV, i.e. the number of panels that can be placed on a roof, which affects the total installed efficiency and power generation per unit area of roof.

Air Ducts Considerations include: 1. Heat transfer to the air • Temperature gain - increased air temperature is important for heating a building or providing process heating to other pieces of equipment dryer, heat exchanger, air conditioning system, desiccant etc. This typically means lower air volumes/velocities. • Absolute heat extraction - total amount of energy that can be extracted from the roof.. • Keeping PV panels cool - air ducts are positioned directly under the PV panels. • Duct Form - Large hot surface area in contact with the air is important for heat transfer. • Duct Length - There are length limitations whereby an increase in length does not necessarily give any great benefit in heating the air in the duct. This depends however on the other factors noted above and below, specifically air volume and velocity. 2. Pressure Drop • Pressure drop in the system is related to length of cladding sheets 9 (and

therefore sheet length), width, depth and shape of air ducts 27. Typically the smaller the air duct 27, the longer the length of sheet and the higher the air velocity, the higher the pressure drop. Pressure drop increases the energy used by the fans which means more electricity is used to generate heat. Pressure drop and heat extraction are optimised to ensure the amount of heat generated per unit of electricity is at a minimum higher than that produced by an efficient heat pump. 3. Noise

* The velocity of the air in the air ducts 27 is an important consideration for noise. Velocity is a function of the cross sectional duct area and the volume of air.

Transport Considerations include: • How do the cladding sheets 9 stack, i.e. do the sheets nest or require special packing materials. • How easy is it to handle the cladding sheets 9 on site, i.e. weight and stiffness, so that the sheets can be handled without damage, particularly on residential applications? • What is the maximum length/width of the cladding sheets 9 that can be readily transported?

Water Carrying Capacity Considerations include: • Are the widths, depths and numbers of gutters 75 sufficient to carry rainwater away before the water becomes deep enough to flood the overlap of successive roof cladding sheets 9 and potentially enter the air ducts 27 and ultimately the roof cavity?

Thermal Expansion • The length of the cladding sheets 9 and the fixing system are dependent at least in part on thermal expansion of the sheet metal.

Figures 18 and 21 are perspective views and side elevations is of a section of a partially-constructed roof of another building with a plurality of roof cladding sheets 9 in accordance with the Figures 1 to 9 embodiment mounted to the roof and a plurality of solar roof panels 35 mounted to the roof cladding sheets 9. As is the case with the Figure 1 to 17 embodiments, the roof cladding sheets 9 are arranged to run down the roof from a ridge 5 to a gutter (not shown)., i.e. so that the air flow ducts 27 of the cladding sheets 9 run from a gutter line to a ridge line.

The same reference numerals are used to describe the same structural features in Figures 18 to 21 that are used in Figures 1 to 17. The main difference between the Figures 18 to 21 embodiment and the Figures 1 to 17 embodiments is that the cladding sheets 9 do not extend the entire distance from the ridge 5 to a gutter (not shown). In the Figures 18 to 21 embodiment the roof has two rows of cladding sheets 9 in side by side relationship across the roof, with the cladding sheets 9 in each row extending a part of the distance between the ridge 5 and the gutter (not shown) of the roof. It is noted that the invention is not limited to two rows of cladding sheets 9 and extends to any suitable numbers of rows. The cladding sheets 9 in successive rows from the ridge to the gutter are aligned in end to end relationship. As can best be seen in Figures 20 and 21, the lower end sections of the upper row of cladding sheets 9 and the upper ends of the lower row of cladding sheets 9 are supported on purlins 71a and 71b of the roof frame 71. The lower end sections of the cladding sheets 9 in the upper row extend at least partly over and thereby overlap the upper end sections of the cladding sheets 9 in the lower row. The roof include a flashing element 81 (Figures 20 and 21) that forms a weather seal art the overlap between the upper and lower rows of cladding sheets 9. The roof includes a plenum chamber (not shown) of the type shown in Figures 10 and 11 that extends along the ridge of the roof for collecting air flow from the outlets of the ducts that are in the upper row of cladding sheets 9 that ends at the ridge. The roof includes a second plenum chamber 77 associated with the lower row of cladding sheets, with the plenum chamber 77 of the type shown in Figures 10 and 11 that extends across the roof for collecting air flow from the outlets of the ducts 27 in the lower row of cladding sheets 9. As is the case with the Figures 10 and11 embodiment, the plenum chamber 77 forms part of an air distribution network for collecting and transferring air that has been heated or cooled by the roof as it flows through the ducts 27 for use as a source of thermal energy in the building or elsewhere, for example for heating or cooling a swimming pool or any other suitable end use application.

The roof also includes electrical connections 83 (Figures 20 and 21) between aligned solar panels 35 in the lower and upper rows of cladding sheets 9. Figures 22 to 24 show another embodiment of a roof in accordance with the invention. The arrow in Figure 23 indicates the direction of water flow over the roof cladding sheets 9 and thereby provides a frame of reference for the orientation of the sheets in Figure 22. The same reference numerals are used to describe the same structural features in Figures 22 to 24 that are used in the other Figures 1 to 15. The main difference between the Figures 1 to 21 embodiments and the Figures 22 to 24 embodiment is the orientation of the roof cladding sheets 9. In the Figures 22 to 24 embodiment the roof cladding sheets 9 extend horizontally across the sides of the roof. Figure 22 is sufficiently detailed to show a number of solar roof panels 35 mounted to some of the roof cladding sheets 9 shown in the Figure. The solar roof panels may be any suitable panels. Figure 22 shows that the roof cladding sheets 9 are relatively long sheets. As indicated above, the arrangement of roof cladding sheets 9 horizontally makes it possible to manufacture custom-sized roof cladding sheets. In general terms, the roof cladding sheet 9 makes it possible to manufacture custom-sized roof cladding sheets that address a variety of ridge, hip, gutter and roof styles. Figure 25 shows another embodiment of a roof in accordance with the invention. In this embodiment the roof is a substantially flat roof (pitch 3-5°) formed from a plurality of the roof cladding sheets 9 of the type used to form the roof shown in Figures 2 to 21 and a plurality of solar roof panels 35 mounted to the sheets 9 and forming a substantially continuous coverage of solar roof panels on the roof. Many modifications may be made to the embodiment of the invention described herein without departing from the spirit and scope of the invention. By way of example, whilst the embodiments of the invention described in relation to the Figures include particular profiles for the roof cladding sheets 9, it can readily be appreciated that the invention is not limited to these particular profiles.

In addition, by way of example, whilst the embodiments of the invention described in relation to the Figures include particular roof configurations, it can readily be appreciated that the invention is not limited to these configurations. In addition, whilst the embodiments of the invention described in relation to the Figures are roof cladding sheets, it can readily be appreciated that the invention is not limited to roof cladding sheets and also extends to wall cladding sheets. Furthermore, whilst the embodiments of invention described in relation to the Figures include (a) a mounting section for mounting a solar roof panel on the roof cladding sheet and (b) a support section for supporting the mounting section of a successive roof cladding sheet, with the mounting section and the support section being parts of one sheet, it can readily be appreciated that the invention is not so limited and extends to embodiments in which the mounting section is a separate sheet and the support section is a separate sheet. In the claims which follow, and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word ''comprise" and variations such as "comprises" or "comprising" are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the end lap system and components of the end lap system as disclosed herein.

Claims

1. A steel cladding sheet for a roof or a wall of a building, the cladding sheet configured to be positioned in side by side overlapping relationship with another said cladding sheet to form part of the roof or the wall, the cladding sheet comprising: a mounting section for mounting a solar panel on the cladding sheet; and a support section for supporting the mounting section of another cladding sheet in side by side overlapping relationship; wherein the mounting section comprises a flat surface to provide a surface area of contact between the solar panel and the mounting section, and wherein the support section is formed to define with the mounting section of the other cladding sheet one or more air flow duct underlying the mounting section in heat transfer relationship with the mounting section for heating or cooling air flow through the duct(s).

2. The cladding sheet defined in claim 1, wherein the cladding sheet includes the solar panel mounted to the mounting section of the cladding sheet.

3. The cladding sheet defined claim 2, wherein the solar panel includes (a) a photovoltaic cell module for converting solar energy into electrical energy and (b) electrical components, such as a wiring junction box and electrical cables and other devices for transferring electrical energy from the solar panel for use in an electrical system of the building or a local electrical network.

4 The cladding sheet defined in claim 2 or claim 3, wherein the solar panel is in the form of a flexible film.

5. The cladding sheet defined in any one of the preceding claims, wherein the cladding sheet is formed so that, in use, the mounting sections of successive cladding sheets in the roof or the wall are in the same plane.

6. The cladding sheet defined in any one of the preceding claims, wherein the support section and the mounting section are formed to define the one or more than one elongate duct extending along the length of the cladding sheets underlying the mounting section when two successive cladding sheets are positioned in side by side overlapping relationship to form the part of the roof or the wall, with each duct having an inlet at one end and an outlet at the other end for air flow along the length of the ducts.

7. The cladding sheet defined in any one of the preceding claims, wherein the support section and the mounting section are of the same width.

8. The cladding sheet defined in any one of the preceding claims, wherein the support section is a profiled section that provides rigidity for the sheet.

9. The cladding sheet defined in any one of the preceding claims, wherein the support section includes one or more parallel rib sections and pan sections between the rib sections.

10. The cladding sheet defined in claim 9, wherein the widths of the pan sections are substantially larger than the widths of the rib sections.

11. The cladding sheet defined in claim 9, wherein the widths of the pan sections are at least twice the widths of the rib sections.

12. The cladding sheet defined in any one of claims 9 to 11, wherein the rib sections have flat tops to provide a stable platform for supporting a mounting section of a successive roof cladding sheet.

13. The cladding sheet defined in any one of claims 9 to 12, wherein the tops of the rib sections and the mounting section are substantially in the same plane.

14. The cladding sheet defined in any one of the preceding claims, further including side edge formations that enable successive sheets to be positioned side by side in overlapping relationship.

15. A roof or a wall that includes a plurality of steel cladding sheets, with the steel cladding sheets positioned in side by side overlapping relationship with one another and including mounting sections for mounting solar panels on the cladding sheets, and support sections for supporting the mounting sections of other steel cladding sheets in side by side overlapping relationship, wherein the mounting sections comprise flat surfaces to provide surface areas of contact between the solar panels and the mounting sections, and wherein the support sections are formed to define with the mounting sections of other cladding sheets in side by side overlapping relationship one or more air flow duct(s) provided underlying each of the mounting sections in heat transfer relationship with the mounting sections for heating or cooling air flow through the duct(s).

16. The roof or the wall defined in claim 15, wherein one group of cladding sheets has a mounting section only and another group of cladding sheets has a support section only.

17. The roof or the wall defined in claim 15, wherein the cladding sheets include a mounting section and a support section as parts of the one sheet.

18. The roof or the wall defined in any one of claims 15 to 17, wherein the roof or wall includes a plurality of solar panels mounted to mounting sections of at least some of the cladding sheets.

19. The roof or the wall defined in any one of claims 15 to 18, wherein the mounting sections form a substantial part, typically at least 90%, of the surface area of the roof or the wall.

20. The roof or the wall defined in any one of claims 15 to 19, wherein the cladding sheets are arranged to extend horizontally across the roof or the wall, such that the longitudinal axes of the sheets are parallel to a ridge of the roof or an upper/lower edge of the wall.

21. The roof or the wall defined in any one of claims 15 to 19, wherein the cladding sheets are arranged to extend down the roof or the wall such that longitudinal axes of the sheets are perpendicular to a ridge of the roof or an upper/lower edge of the wall.

22. The roof or the wall defined in any one of claims 15 to 21, wherein the cladding sheets include the cladding sheet defined in any one of claims 1 to 14, whereby, in the roof or the wall, the support section of one cladding sheet underlies and supports the mounting section of a successive cladding sheet.

23. The roof or the wall defined in claim 22, wherein the support section of one cladding sheet and the mounting section of another cladding sheet define the one or more than one elongate air flow duct extending along the length of the cladding sheets underlying and in direct heat transfer relationship with the mounting section.

24. The roof or the wall defined in claim 23, wherein the direct heat transfer area is at least 60%, typically at least 70%, and more typically at least 80%, of the area of the mounting section.

25. The roof or the wall defined in claim 23 or claim 24, wherein each duct has an inlet at one end and an outlet at the other end for air flow along the length of the ducts.

26. The roof or the wall defined in any one of claims 23 to 25, wherein each duct is a closed duct along the length of the duct at the overlap between a support section of one cladding sheet and the mounting section of the successive cladding sheet.

27. The roof or the wall defined in any one of claims 23 to 25, includes a weather seal, such as a foam seal, along the length of the duct at the overlap between a support section of one cladding sheet and the mounting section of the successive cladding sheet.

28. The roof or the wall defined in any one of claims 23 to 27, further including a system to minimise the ingress of air-borne impurities and vermin into the one or more ducts.

29. A roof or a wall of a building that includes a plurality of steel cladding sheets mounted in side by side overlapping relationship, with the steel cladding sheets including cladding sheets that define (a) mounting sections for solar panels, the mounting sections comprising flat surfaces to provide surface areas of contact between the solar panels and the mounting sections, (b) support sections for supporting the mounting sections of other steel cladding sheets, and (c) air flow ducts underlying the mounting sections in heat transfer relationship with the mounting sections for heating or cooling air flowing through the ducts, the air flow ducts being defined by the mounting sections and support sections of cladding sheets in side by side overlapping relationship and with the ducts having inlets at one end of the ducts and outlets at the other ends of the ducts.

30. A system for generating electrical energy from solar energy that includes converting solar energy that is incident on solar panels on the roof or the wall defined in any one of claims 15 to 29 into electrical energy.

31. A system for generating electrical energy and thermal energy from solar energy that includes converting solar energy that is incident on solar panels on the roof or the wall defined in any one of claims 15 to 29 into electrical energy and thermal energy and converting solar energy that is otherwise incident on the roof or wall into thermal energy.

32. The system defined in claim 31, wherein the system includes an air distribution network for collecting and transferring air that has been heated or cooled by the roof or the wall defined in any one of claims 15 to 29 as it flows through the air flow ducts of the roof or the wall for use as a source of thermal energy in the building or elsewhere, for example for heating or cooling a swimming pool.

33. The system defined in claim 32, wherein the air distribution network is arranged for collecting and transferring heated or cooled air from the outlet ends of the ducts of the roof to the building for direct space heating or cooling of the building.

34. The system defined in claim 32 or claim 33, wherein the air distribution network includes (a) a plenum chamber in the roof space that is connected to and receives heated or cooled air from the outlet ends of the ducts in the roof, and (b) a duct for transferring heated or cooled air to the building.

35. The system defined in claim 34, wherein the air distribution network includes a fan for causing air flow into and from the plenum chamber and through the duct for transferring heated or cooled air to the building.

36. An integrated heating and cooling system for a building which includes the system defined in any one of claims 31 to 35 for collecting and transferring air that has been heated or cooled by the roof or the wall defined in any one of claims 16 to 30 as it flows through the air flow ducts of the roof or the wall for use as a source of thermal energy in the building.

37. The system defined in claim 35, further including a controller that senses the energy requirements for the building and operates the roof system as required to meet the energy requirements.

38. The system defined in claim 37, includes internal and external sensors for providing data to the controller.

39. The system defined in claim 38, wherein the sensors include a sensor for sensing the temperature of the roof cladding sheets.