GB2461342A

GB2461342A - Glazing installation

Info

Publication number: GB2461342A
Application number: GB0812209A
Authority: GB
Inventors: David John Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-07-03
Filing date: 2008-07-03
Publication date: 2010-01-06
Also published as: GB0812209D0

Abstract

A glazed roof or wall, particularly for use in a conservatory, comprising an outer glazing member 82 supported by a frame 12, a separate inner glazing member 84 also supported by the frame opposite the outer glazing member. The frame may comprise first and second members which support opposite edges of the glazing members. There may also be thermally insulating extension members secured to the inner faces of the support members. There may be a thermally and/or acoustically insulating spacer system 90 between the glazing members to define a sealed space. Thermal and/or acoustic insulating material and/or heat absorbing or reflecting material may be located between the glazing members. There may be an airflow or piping for conducting a fluid between the glazing members to remove heat collected by the roof or wall. Also disclosed is a method and kit for upgrading a glazed roof or wall.

Description

GlazinR Installations

Field of the Invention

The invention relates to glazing installations and particularly, but not exclusively, to glazed roofing for building structures such as conservatories and the like.

Background to the Invention

One of the parameters that needs to be taken into account when designing conservatories and similar such structures is the reduction of thermal transmission to allow for comfortable use of the conservatory and economic heating during the winter months. Known single sheet glazing panels used for conservatory roofing typically have a depth of 25, 32 or 35 mm. Typical thermal transmittance (U) values for such sheets are 1.4 W/m2 or above. Single thickness sheets having a depth of 55mm and a U value of less than 1 W/m2 are known. However, the depth of these sheets is such that they are only suitable for lean to roofs' and cannot be readily installed on conservatories having shaped ends, such as those having Victorian and Edwardian-style roofs. The reason for this is that a depth of 55mm cannot be fitted in standard size glazing bar covers and increasing the glazing bar cover width to accommodate such depths would result in cumbersome and unattractive designs.

In addition to the U value of the glazing used, account must be taken of the relatively low insulation values of the glazing bars and other structural members used to support the glazing. Many installations make use of metal glazing bars and the insulation values of such installations are limited by the high thermal conductivity of the metals used (for example aluminium alloys) and the inadequate thermal breaks provided to limit heat losses through them. The result can be significant heat losses through the glazing bars, which often leads to condensation forming on the lower sides of the glazing bars and may result in mildew. This can be a particular problem in conservatories that are adjacent a bathroom or kitchen, or where there are plants in the conservatory, all of which can be sources of significant quantities of moisture.

Another factor that should be taken account of is the need to provide protection against summer heat to allow conservatories to be used in comfort during the summer months. A reduction in solar heat entering the roof or side glazing of 70% or more is desirable to provide a comfortable environment within a conservatory. To achieve this, the glazing needs to exclude solar heat before it enters the conservatory.

It is also desirable to provide glare protection, particularly during the summer months, to alleviate discomfort to the eye. The complex internal structure of at least some known glazing sheets can be a cause of glare due to multiple internal reflections of the sun's rays leading to the production of an arc, or band of brightness and light scattering.

An undesirable feature of conservatory roofs made using conventional hollow plastics glazing sheets is the drumming noise produced by rain and hail striking the sheet and any reduction in such noise is desirable.

An object of the invention is to provide glazing installations, including glazed roofing, that provide improved performance in at least one of these areas, or an alternative to existing products on the market.

Summary of the Invention

The invention provides a glazed roof or wall comprising an outer glazing member supported by a glazing support frame and a separate inner glazing member disposed inwardly of and generally opposite said outer glazing member, said inner glazing member being supported by said glazing support frame.

The invention also includes a method of upgrading a glazed roof or wall which glazed roof or wall comprises a glazing support frame and a plurality of existing glazing members supported by said glazing support frame to define an existing glazing layer, said method comprising fitting additional glazing members to said support frame generally opposite said existing glazing members to define an additional glazing layer.

The invention also includes a kit for upgrading a glazed roof or wall which glazed roof comprises a glazing support frame and a plurality of existing glazing members supported by said glazing support frame to define an existing glazing layer, said kit comprising a plurality of additional glazing members and a plurality of additional glazing member supports fittable to said support frame for supporting said additional glazing members in generally opposed relation to respective existing glazing members to define an additional glazing layer.

Brief Descrii,tion of the Drawings In order that the invention may be well understood, some embodiments thereof, which are given by way of example only, will now be described with reference to the drawings in which: Figure 1 is a schematic view of a known glazing support member; Figure 2 is an exploded schematic view of components of a glazed roof; Figure 3 is a schematic view of a glazed roof comprising components corresponding generally to the components shown in Figure 2; Figure 4 is a schematic view of another glazed roof; Figure 5 is a schematic view of yet another glazed roof; Figure 6 is a schematic view of still another glazed roof; Figure 7 is a schematic cross-section through a cellular glazing sheet for the glazed roofs of Figures 2 to 6; and Figure 8 is a schematic of a glazing panel for the glazed roofs of Figures 2 to 6 and comprising two of the cellular glazing sheets of Figure 7.

Detailed Description of the Illustrated Embodiments Referring to Figure 1, a known glazing support member 10 comprises a generally rectangular support bar 12 and a pair of barbed uprights 14 extending perpendicular to the support bar. The barbed uprights 14 are spaced apart to define a receiving space 16 between them. The barbs 18 of the barbed uprights are disposed in the receiving space 16 as pairs of opposed barbs. On either side of the barbed uprights 14, the support bar 12 provides a ledge 17 on which an edge of a glazing member such as a single glazing sheet or a multiple-sheet glazing panel can be supported. A gasket 20 is provided at the free edge of each ledge 17. The gaskets 20 extend continuously along the length of the glazing support member 10. Although not shown, the gaskets 20 are, for example, located and held on the support bar 12 by respective lengthways extending T-formations formed on their undersides that engage in respective T-slots provided on the ledges 17.

The glazing support member 10 additionally comprises a glazing bar cover 22 that is securable to the support bar 12 to hold respective glazing members in place on the ledges 17. The glazing bar cover 22 is a plastics extrusion and comprises two resilient central members 24 that have respective ribs 26 at their free ends. The central members 24 extend perpendicular to a generally planar centre portion 28 of the glazing bar cover 22 and axially along the length of the glazing bar cover. Respective wings 30 extend from the lengthways extending edges of the centre portion 28. The wings 30 are arcuate in section and curve from the edges of the centre portion 28 such that their free edges are closer to the ribs 26 than is the centre portion. The free edge of each wing 30 has a gasket 32 extending along its length.

In use, the edges of respective glazing members (not shown) are seated over the ledges 17 of the support bar 12 on either side of the barbed uprights 14. The central members 24 of the glazing bar cover 22 are then aligned with the receiving space 16 and thrust into the receiving space by pressing the glazing bar cover towards the support bar 12. The resilience of the central members 24 allows them to deflect towards one another so that the ribs 26 can be pushed past the barbs 18. The depth to which the central members 24 can penetrate the receiving space 16 depends on the depth of the glazing members seated on the ledges 17. The configuration of the barbed uprights 14 and central members 24 is such that the ribs 26 will snap behind one of the opposed pairs of barbs 18 when the appropriate insertion depth for a particular depth of glazing members is reached. In the inserted position, the wings 30 of the glazing bar cover 22 flex away from the support bar 12 and the energy stored in the wings as a result of this flexing serves to compress the gaskets 20, 32 against the opposed faces of the glazing members such that the glazing members are sealingly secured to the glazing support member 10.

The known glazing support member 10 is designed to support two glazing members (one on each ledge 17) and is used to form conventional glazed roofs having a single glazing layer. Figure 2 illustrates a modification to the known glazing support member 10 that allows the modified glazing support member 1OM to support four glazing members to allow the construction of glazed roofs having two (an inner and an outer) glazing layers. For ease of description, parts common to the known glazing support member 10 and modified glazing support member 1 OM will be referenced using the same reference numeral.

The modified glazing support member 1OM is able to support respective glazing members 40 on its ledges 17 in much the same way as the known glazing support member 10. The modified glazing support member 1OM is provided with inner glazing member supports 42, 44 for supporting an additional two glazing members 46.

The additional glazing members 46 are disposed inwardly of the glazing members 40 and so will be referred to as inner glazing members while the glazing members 40 are referred to as outer glazing members. As can be seen in Figure 2, the inner glazing member supports 42, 44 are of slightly different design and it will be understood that while not essential, the glazing support member I OM will usually be provided with a pair of like inner glazing member supports, rather than one of each design.

The inner glazing member support 42 is an elongate plastics extrusion comprising two parallel arms 48, 50 that are separated and interconnected by a leg 52 that extends between and perpendicular to the two arms. When assembled to the support bar 12, the arm 48 rests on the ledge 17 and associated gasket 20 and the leg 52 depends from the arm 48 along a side 56 of the support member 12. The arm 50 is then positioned between the ledge 17 and an innermost, or bottom, face 58 of the glazing support member I OM to provide a support surface for an inner glazing member 46.

The inner glazing member support 44 has the same features as the inner glazing member support 42 together with an additional leg 60 that extends from and perpendicular to the arm 48 in a direction away from the arm 50. In use, the inner glazing member support seats 44 rests on the ledge 17 and associated gasket 20 in the same way as the inner glazing member support 42 with the arm 50 positioned between the ledge 17 and bottom 58 of the glazing support member 10. The difference is that the leg 60 extends perpendicular to the ledge 17 and parallel to the barbed uprights 14.

It will be understood that although the inner glazing member supports 42, 44 are described as being plastics extrusions, they could be made of a folded metal sheet. It will be appreciated that plastics supports will provide better thermal and acoustic insulation than metal supports. However a metallic glazing support can be made thinner than a plastics glazing member support while retaining the necessary strength for the support function and having a thin support enables the support to be positioned in between the gasket 20 and outer glazing member without adding significantly to the depth of the space between the gasket 20 and gasket 32 needed to accommodate them.

In the case of the inner glazing support member 42, making it thinner increases the likelihood of the arm 48 being insertable between the gasket 20 and outer glazing member without having to either remove the outer glazing member or loosen the glazing bar cover 22. Alternatively, instead of being members that extend continuously along the length of the glazing support member 10, the inner glazing member supports could be provided in the form of clips having a profile corresponding to that of either of the inner glazing member supports 42, 44 and fitted to the glazing support member 10 in series at intervals along its length.

Figure 3 shows a glazing installation in the form of a glazed roof 80 comprising components corresponding generally to the components shown in Figure 2. The glazed roof 80 comprises glazing support frame comprising a first glazing support member lOM and a second glazing support member 1OM. The first and second glazing support members 1OM are disposed in opposed, typically parallel spaced apart, relation so as to be able to support opposed edge regions of an outer glazing member 82 and an inner glazing member 84 in the space between them. Each glazing support member 1OM is able to support two outer glazing members 82 and two inner glazing members 84. The outer glazing members 82 are supported on the ledges 17 of the respective support members 12 and the inner glazing members 84 are supported by the arms 50 of the respective inner glazing member supports 42 (the inner glazing member supports are not shown in Figure 3, but are as illustrated in Figure 2). For ease of reference, in the description that follows, mention will only be made of the inner glazing member support 42. However, it is to be understood that unless otherwise stated, the inner glazing member support used could be an inner glazing member support 44 in place of the inner glazing member support 42.

In the illustrated embodiment, the length of the legs 52 of the inner glazing member supports 42 and the depth of the inner glazing members 84 is such that the innermost major faces 86 of the inner glazing members are disposed substantially flush with the bottom faces 58 of the glazing support members 1OM and the inner glazing members are suspended behind the outer glazing members 82 such that there is a space 88 defined between each pair of opposed glazing members 82, 84. However, the length of the legs 52 andlor depth of the inner glazing members 84 can be selected such that there is contact between the opposed major faces of the outer and inner glazing members 82, 84 and/or the innermost major faces 86 of the inner glazing members are disposed at a desired level somewhere between the ledges 17 and the bottom faces 58 of the glazing support members 1OM.

Figure 4 shows a glazing installation in the form of a glazed roof 100 comprising a glazing support frame comprising a first glazing support member 10MM and a second glazing support member 10MM. The first and second glazing support members 10MM are disposed in opposed, typically parallel spaced apart, relation for supporting opposed edge regions of an outer glazing member 102 and an inner glazing member 104 therebetween. Each glazing support member 10MM is able to support two outer glazing members 102 and two inner glazing members 104.

The glazing support members 10MM differ from the glazing support members I OM of Figures 2 and 3 in that they include an extension member 112 that increases their depth and have a different fitting for supporting the inner glazing members 104. As in the arrangements shown in Figures 2 and 3, the outer glazing members 102 are supported on the ledges 17 and associated gaskets 20 of the support bars 12. The inner glazing members 104 are supported on ledges 106 provided by inner glazing member supports 108 that are secured to the bottom faces 110 of the first and second glazing support members 10MM. In the illustrated embodiment, the bottom faces 110 of the glazing support members 10MM are defined by the extension members 112.

The extension members 112 are fitted to the innermost faces 114 of the support bars 12.

According to the materials from which the parts are made, the inner glazing member supports 108 can be secured to the extension members 112 by means of screws (metal or plastics) or similar such fastening devices, or by an adhesive. Alternatively, one or more cooperating push-fit fastening devices (not shown) can be fitted to or formed on the bottom faces 110 defined by the extension members 112 and the opposed faces of the inner glazing member supports 108 so that the inner glazing member supports can be secured to the glazing support members 10MM by a simple push fitting action.

For example, the bottom faces 110 of the extension members 112 can be provided with a lengthways extending groove configured to snap-fittingly engage projections provided on the opposing faces of the inner glazing support members 108.

Although not shown, when the inner glazing member supports 108 are fitted to the extension members 112 by screws, a cover strip may be provided to hide the screws for cosmetic purposes. The cover strip may be snap-fitted or glued to the inner glazing member supports.

The extension members 112 can fulfil one or both of two functions. The first function is that of increasing the depth of the glazing support members of an existing glazed roof to allow the use of inner glazing members 104 having a greater depth than could be used if the inner glazing member supports 108 were fitted directly to an unextended glazing support member. The second function is to increase the thermal insulation capacity of the glazing support members. This can be achieved by making the extension members 112 from a highly insulating material, for example a rigid foam, andlor making it hollow such that it contains one or more thermally insulating air gaps.

In the illustrated embodiment, the inner glazing members 104 are sufficiently deep to occupy the full depth of the space between the innermost major faces of the outer glazing members 102 and the ledges 106 of the inner glazing members supports 108 so that there is substantially no space between the opposed major faces of the outer and inner glazing members 102, 104. However, it will be appreciated that the depth of the inner glazing members 104 may be such that there is a space between the outer and inner glazing members corresponding to the space 88 shown in Figure 3.

It will be understood that the inner glazing member supports 108 can be used in installations that do not include extension members 112. For example, inner glazing member supports 108 could be fitted to the bottom faces 58 of the glazing support members 1OM of Figure 3 to support the inner glazing members 84 in place of the inner glazing member supports 42, 44.

Figure 5 shows a glazed roof 120 comprising a glazing support frame comprising a first glazing support member 10 and a second glazing support member 10. The first and second glazing support members are disposed in opposed, typically parallel spaced apart, relation for supporting opposed edge regions of an outer glazing member 122 therebetween. Each glazing support member 10 is able to support two outer glazing members 122.

The glazed roof 120 further comprises inner glazing members 124 that are supported on the innermost faces 126 of the first and second glazing support members 10. As shown in the drawing, the inner glazing members 124 may be fitted to the innermost faces 126 of the glazing support members 10. An inner glazing member 124 that is sufficiently wide may bridge one or more glazing support members 10 as illustrated with the right-hand (as viewed in the drawing) inner glazing member. Alternatively, the glazing support member 10 may bridge the position at which the edges of two inner glazing members 124 meet as illustrated with the left-hand (as viewed in the drawing) glazing support member. Typically, the inner glazing members 124 are secured to the glazing support members 10 by means of screws, or other suitable fasteners, that penetrate the innermost face 126 of the glazing support members 10.

Where the appearance of the installation is important, the cosmetic facia strips 128 can be used to hide the fasteners. In cases in which two inner glazing members 124 meet on the innermost face 126 of a glazing support member, the facia strip 128 may be provided with a first part of a push-fit fastening system for fitting through a gap between the opposed edges of the two inner glazing members 124 and into a second part of the push-fit fastening support system provided in the glazing member support 10. The push-fit fastening system may be similar to that shown in Figure 1 for securing the glazing bar cover 22 to the support bar 12, although, it is to be understood that any suitable push-fit fastening arrangement can be used.

The positioning of the inner glazing members 124 is such that there is a gap 129 defined between the opposed faces of the inner and outer glazing members 122, 124.

For the same depth of glazing bar, this gap 129 will always be deeper than the gaps that can be provided with the form of installation shown in Figures 3 and 4, which may be advantageous in installations in which the glazed roof is used to harvest solar energy as explained in more detail below. Of course, if a greater depth is required, extension members such as the extension members 112 could be fitted. Another feature of the glazed roof 120 is that the inner glazing members 124 act as a thermal break isolating the glazing support members 10 from the warm air in the space covered by the glazed roof, which means that the provision of insulating extension members as shown in Figure 4 should not be necessary for the purpose of achieving high insulation values for the glazed roof.

Figure 6 shows a glazed roof 130 having a structure that is more likely to be the result of the upgrading of an existing roof, rather than being adopted for a new build glazed roof. The glazed roof 130 a glazing support frame comprising a first glazing support member 10 and a second glazing support member 10. The first and second glazing support members are disposed in opposed, typically parallel spaced apart, relation for supporting opposed edge regions of an outer' glazing member 132 therebetween.

Each glazing support member 10 is able to support two glazing members 132. In this embodiment, an outer glazing layer is formed by additional glazing members 134 fitted to the glazing bar cover 22 or directly to the support bar 12 with the glazing bar cover removed. The additional glazing members 132 may be secured to the glazing support members 10 by means of screws, or other suitable fasteners, fastening into the support bars 12. Advantageously, the additional glazing members 134 are fitted to the glazed roof 130 such that there is a gap 135 between them and the opposed glazing members 132. However, the installation could be such that the two glazing layers are in contact like the two glazing layers 102, 104 shown in Figure 4.

For installations in which appearance is important, cosmetic facia strips 136 may be provided. The facia strips 136 may also be used to provide a degree of protection against the ingress of water where two additional glazing members 134 meet (as shown to the left-hand side in Figure 6). When the facia strips 136 are used to provide waterproofing, they are advantageously provided with gaskets (not shown), which, in use, are trapped between the additional glazing members 134 and the opposed faces of the facia strips. For installations in which the glazing bar covers 22 are secured to the support bars 12 by a push-fit fastening system, it may be advantageous to remove the glazing bar cover and provide facia strips 136 with a complementary push-fit fastening part such that the facia strips can be used to secure the additional glazing members 132 to the glazing support members 10 via gaps (not shown) left between the edges of adjacent additional glazing strip members.

In this embodiment, it will not usually be necessary to provide for insulation of the glazing member supports 10 as the additional glazing members 134 will act as thermal breaks.

By providing a second glazing layer in the form of the inner glazing members as illustrated in Figures 2 to 5 or an external layer of additional glazing members as shown in Figure 6 in either a new glazed roof or by retrofitting to an existing glazed roof, significant improvements in the U value of the glazed roof can be obtained. The glazing members used to form the inner, or additional, glazing layer can be of any suitable design. A presently preferred option is to use a transparent plastics glazing sheet 140 having a hollow interior divided into a number of cells 142 as shown in Figure 7. The glazing sheet 140 may be used as a single layer or in a glazing panel as shown in Figure 8. The nominal depth of the glazing members 140, 160 can be in the range 16 to 55mm as desired. In the case of the glazed roofs 80, 100 the maximum depth of the glazing members 140, 160 will be that permitted by the depth of the glazing support members 1OM, 10MM.

Referring to Figure 7, the glazing sheet 140 is a hollow plastics cellular glazing sheet and may be formed by a plastics extrusion process. The glazing sheet 140 has a plurality of rectangular cells 142 defined between the outer surface elements 144 by a plurality of walls 146 that extend parallel to the outer surface elements and a plurality of transverse walls 148 that extend transverse (in this case perpendicular) to the outer surface elements. The height 150 of the cells 142 is determined by the mutual spacing between adjacent outer surface elements 144 and walls 146. The cells 142 may be further subdivided by inclined webs, such as the webs 152. In one embodiment, the five horizontal walls 144, 146 of the glazing sheet 140 are configured to provide a glazing sheet having a nominal depth 154 of 16mm with the result the cells 142 have a nominal height 150 of approximately 4mm.

Referring to Figure 8, the glazing panel 160 comprises two glazing panels 140 separated by a perimeter spacer system 162 comprising at least one spacer member.

The spacer system 162 has a thickness of approximately 3mm and separates the two glazing sheets 140 so as to provide a 3mm space 164 between them. The configuration and positioning of the spacer system is such that the space 164 extends over substantially the entire length and width of the glazing panel 160. The space effectively provides an additional cell having a height of approximately 3mm. The space 164 may be left empty as an air gap. However, the space 164 can be completely or partially filled by a material 169 selected to further enhance the performance of the glazing panel.

The two glazing sheets 140 could be bonded to the spacer system 162. However, due to the relatively small contact areas provided by the spacer system 162, a more durable structure can be produced by uniting the three layers 140, 162 by means of suitable adhesive tape 166 or other securing system such as U-shaped plastics clips 168 bonded to the glazing sheets 140. The securing system is not limited to an adhesive tape or generally U-shaped clips as shown in Figure 8. In principle, any suitable clamping or fixing system could be used. For example, the securing system may comprise perimeter strips or channels running around the circumference of the glazing panel.

The glazing sheet 140 and glazing panel 160 and various modifications thereto are described in greater detail in the Applicant's co-pending application titled Glazing' GOB122iO3 (Agent's Reference P00063GB) filed on the same day as the present application, the entire content of which is incorporated herein by reference.

For a new build glazed roof having a structure the same as, or similar to, the glazed roofs 80, 100, 120 of Figures 3 to 5, the presently preferred glazing comprises an outer glazing member in the form a glazing panel such as the glazing panel 160 comprising two glazing sheets 140 having a nominal depth of 16mm, each with a four-high cell structure and with a 3mm air gap between the two glazing sheets and an inner glazing member comprising a single transparent plastics glazing sheet similar to the glazing sheets 140 (but having a nominal depth of 25mm) and positioned such that there is a space of between the inner and outer glazing members having a depth of approximately 3mm. The resultant nominal 60mm depth of the glazing layers would have a U value in the region of 0.66. If the 25mm depth inner glazing member were replaced by a glazing sheet having the same nominal 16mm depth as the glazing sheets 140 of the outer glazing member, the U value would be in the region of 0.76.

In embodiments of the glazed roofs 80, 100, 120, 130 provided with a space between the two layers of glazing members, the space can be left empty, in which case, it will provide some acoustic insulation. This will result in a reduction in the transmission of external noise, particularly the drumming noise associated with rain beating on the outer glazing members. Additionally, the space will provide a thermally insulating air gap that reduces heat losses through the glazed roof 80, 100, 120, 130. Alternatively, various materials can be put into the space between the inner and outer glazing members to engineer the thermal, acoustic and light transmission characteristics of the glazed roofs. For example, the thermal insulating capacity of the glazed roof can be improved by introducing a thermally insulating material into the space. The insulting material can be in sheet or loose form, such as lightweight polystyrene sheets or other lightweight expanded plastics structures, or organic and inorganic materials incorporated in a variety of forms such as bubbles, beads, foams, sheets, amorphous or wool/fibrous structures; examples include polyurethane and isocyanides foams and hollow glass or plastics beads. The insulating material may substantially fill the space between the two layers of glazing members or may, for example when in sheet form, lie loose in the space. The incorporation of such an insulating material into the space between the glazing member layers can reduce the 0.66 and 0.76 U values mentioned above to 0.6 and 0.7 respectively.

With glazed roofs such as the glazed roofs 80, 100, 120, 130 described above, the potential heat losses through glazing support members are more significant than in a conventional glazed roof structure in view of the high insulation values achievable by having the inner and outer glazed layers. Ultimately the heat lost through the glazing support members limits the overall insulation performance of the glazed roofs. As previously mentioned, in the case of the glazed roofs 120, 130, the glazing members 124, 134 of the additional glazing layer serve to provide insulation for the glazing support members 10. To further improve the insulation performance of glazed roofs such as the glazed roofs 80, 100, a thermally insulating extension member, such as the extension member 112, can be fitted to the bottom face of the glazing support members. By suitably configuring the overall structure and making the extension members of a suitable insulating material, the extension members and inner glazing members can thermally isolate the glazing support members from the interior of the conservatory, thereby improving the thermal insulation performance of the glazed roofs 80, 100 and reducing the likelihood of condensation forming on the glazing support members. It will be understood that although not shown in the drawings, thermally insulating extension members can be used for glazed roof structures that have inner glazing member supports such as those shown in Figures 2 and 3 and not just for structures such as that shown in Figure 4.

As indicated above, a space, such as the spaces 88, 129, 135, provided between the glazing members that form the inner and outer glazing layers will in itself reduce the volume of sounds transmitted through the glazed roof. The soundproofing provided by the space 88, 129, 135 can be enhanced by sealing the space or otherwise acoustically isolating the two layers of glazing from one another. Thus, for example, a perimeter sealing system comprising sealing strips, such as the sealing strips 90 shown in Figure 3, may be provided between the inner and outer glazing members 82, 84. In a glazed roof structure such as those shown in Figures 5 and 6, an acoustic insulating material could be provided between the glazing support members 10 and the glazing members 124, 134 that form the additional glazing layer. The material used should be a relatively soft acoustically dead material, such as rubber. Other materials that could be used that can provide various degrees of sound deadening include various soft plastics materials and wood. It will be appreciated that in general, the use of a sealing system made of such materials will also improve the overall insulation value of the glazed roof. It will also be appreciated that a material with good acoustic insulation properties can be put in the space between the two glazing layers by itself or in conjunction with the thermal insulating material mentioned above and that many materials also provide good thermal insulation will also provide acoustic insulation.

It will be understood that if the glazing members forming the additional glazing layer comprise a cellular glazing sheet such as the glazing sheet 140 shown in Figure 7 or a glazing panel such as the glazing panel 160 shown in Figure 8, the cavities in the glazing sheet/glazing panel will further reduce the sound transmitted by the glazed roof.

In addition, or as an alternative, to using the space between the two layers of glazing members to house thermally andlor acoustically insulating materials, the solar protection afforded by the glazed roofs 80, 100, 120, 130 can be improved by putting heat reflecting and/or heat absorbing materials in the space. The heat absorbing and/or heat reflecting materials can include laminated and/or dyed films that are opaque, translucent or transparent (including translucent metallised plastics laminates with heat absorbing and/or heat reflecting properties) or thin metal sheets, such as thin aluminium sheets. When thin sheets or films are used, they will typically be so thin it is desirable to make them stiffer by embossing in order to improve their handleabiltiy.

For installations that will be subject to relatively high levels of heat, a dark metal mesh may be a more suitable form of heat absorber, as such meshes should withstand higher temperatures than films and thin sheets. The mesh may be a woven or welded wire mesh or an expanded metal mesh. As an alternative to a mesh, a perforated metal sheet could be used. By selecting suitable heat reflecting or heat absorbing materials, the amount of solar heat that passes through the glazed roof can be considerably reduced, thereby making the conservatory comfortable to use during those parts of the year in the solar heat impinging on the glazed roof is at its strongest.

It will be understood that all of the above described measures for providing thermal and/or acoustic insulation and/or solar protection by placing suitable materials in the space between the inner and outer glazing layers can be applied to glazed roofs such as the glazed roof shown in Figure 4 by inserting a layer or layers of suitable material between the inner and outer glazing members such that the inserted materials are sandwiched between and are in contact with both the inner and outer glazing members to form a laminate structure. It will also be appreciated that where glazing sheets 140 and glazing panels 160 such as those shown in Figures 7 and 8 are used, thermal and/or acoustic insulation and/or solar protection can be provided by introducing suitable materials into cells 142 of the cellular glazing sheet or into the space 164 between the glazing sheets 140 of the glazing panel 160 in the ways described in detail in the Applicant's co-pending application mentioned above. It will be understood that the desired properties required of the glazed roof can be engineered by suitable selection of the glazing sheets andlor glazing panels used and the way in which they are incorporated into the roof structure. Thus, for example, the glazing panels used to form the outer glazing layer may incorporate suitable materials for reflecting and/or absorbing heat to provide solar protection, while the space between the two glazing layers is occupied by a material intended to improve the thermal andior acoustic insulation provided by the glazed roof. Another alternative, possibly for upgrading an existing glazed roof having glazing members made of glass, would be to provide inner glazing members equipped to improve the thennal insulation of the glazed roof with heat reflecting or heat absorbing materials between the inner and outer glazing members to provide solar protection.

Where the glazed roof is provided with heat absorbing or reflecting materials as described above, the heat that is collected can be used to heat a building or structure with which the glazed roof is associated. By way of an example of the heat that can be harvested from such glazed roofing, up to 0.8KW/m2 of heat falls upon glazing that is at 90° to the solar radiation. For a typical size of conservatory, the peak solar energy falling onto the surface of the glazing may be up to around 8KW and that figure can be greater for larger conservatories. Thus, for example, in the case of a glazed roof having a space between the two glazing layers such as the glazed roofs 80, 100, 120, 130, if the space is only partially filled by the heat absorbing or reflecting material, heat will be collected in the empty space and since the space is only partially filled, air can be moved through it so that the heat can be captured and transported to a heat exchanger by the moving air. The airflow may be natural or forced. Natural ventilation will be more effective when the depth of the space is relatively larger and so, for a given depth of glazing member support, better results should be obtained by fitting the glazing members of the inner glazing layer to the undersides of the glazing support members as shown in Figure 5, rather than in the space between adjacent glazing support members as shown in Figure 3.

Where the glazed roof is intended to fulfil a heat harvesting function, metal heat absorbers, such as the previously mentioned dark metal mesh heat absorbers should provide better results than films, thin sheets and the like. This is because the metal meshes can achieve higher temperatures than films, which will usually distort at relatively low temperatures (typically 100 -120°C), and temperatures of at least in the region of 100°C to 160°C (depending in part on the rate of the airflow removing the heat) may be found in the area around the heat absorbers or reflectors. The metal mesh would work particularly well in combination with inner andlor outer glazing members made of glass as extremely high temperatures, which may be greater than a plastics glazing member can withstand could be achieved.

It will be understood that the spaces between and/or within the glazing members/glazing sheets through which the airflow passes to collect the solar heat energy can be interconnected andlor communicate separately in many ways. For example, the connection may be via passages provided within the members of the glazing support frame, such as wall and eaves beams and/or ridge beams. In cases in which an existing glazed roof is being upgraded, the existing glazing support frame members may not be suitably configured to provide passageways for the heated airflow and so it may be desirable to provide dedicated passage providing connectors.

It will be appreciated that heated air expands by up to 35% and with natural ventilation and the stack effect, the heated airflow obtained can be used to drive a small turbine for generating electricity located upstream of the heat exchanger to which the heated air is passed. The turbine will typically be connected to a battery, which is used to store the electrical energy produced.

As an alternative to collecting heat by means of an airflow, the heat may extracted in a heated water flow. As shown in Figure 5, micro bore, or other, piping 170 can be run through the spaces between the two glazing layers. The extra depth of space obtainable by fitting the inner glazing layer to the underside of the glazing support members 10 as shown in Figure 5, as compared with an arrangement in which the inner glazing members are fitted between adjacent glazing support members as shown in Figure 3, may be preferred to allow for the incorporation of the pipe work and heat absorbing and or reflecting materials without the need to provide extension members to increase the space available. To increase the efficiency of the heat collection process, the piping may be finished in black or otherwise treated so as to absorb solar energy direct in addition to being heated by the heat collected in the space between the two glazing layers. The high insulation and heat collection properties that can be engineered into the glazed roofs as described above allow for very efficient heat collection to provide a flow of heated fluid to a heat exchanger 172 for, for example, providing a flow 174 of heated water. If glass glazing members are used, temperatures in excess of 100°C can be achieved to allow steam to be generated in a pressure system, which can be used to drive a turbine or other engine (for example a reciprocating piston engine) to generate electricity. It is believed the efficiencies in insulation and heat collection obtainable with the described glazed roof structures are such that shorter payback periods than are obtainable with conventional solar panels can be achieved. For example, the glazed roofs should be more effective than conventional solar panels at generating heat on the relatively dull days that typically occur more frequently in the autumn, winter and spring. Thus, higher levels of energy collection should be obtainable throughout the year than is possible with a conventional solar panel.

As one possible alternative to the heat collection system 170, 172 described above the pipes 170 could form a closed heat collection system with heat collection and subsequent heat transfer from the system being obtained by vaporising and condensing a fluid contained within the pipes. This alternative will now be described with reference to the features 170, 172, 174 shown in Figure 5. In this system the pipes 170 have sealed ends and extend through the space 129 to a manifold 172 located at a height above that of the space 129. The sealed pipes 170 contain a fluid (for example a water-glycol mixture) that will vaporise when subjected to heating within the space 129. A separate fluid flow 174 (for example water) is channelled through the manifold 172 to cool the vapour in the sealed pipes 170. In use, the vapour produced within the portions of the pipes 170 located within the space 129 rises to the ends of the pipes that are connected to the manifold 172. Here the vapour is exposed to the cooling effect of the fluid flow I 74. The fluid flow 174 extracts heat from the vapour causing it to condense. The condensate falls back down the pipes to be re-vaporised in portions of the pipe within the space 129. The heated fluid flow 174 flows to a storage tank where it is stored to provide a source of heated liquid. This system could be modified by having the ends of the sealed pipes at which the condensation process occurs connected to a heat exchanger within a water storage tank to directly heat the water in the storage tank.

As an alternative to collecting heat within the glazed roof structure solar energy can be allowed to pass through the roof and advantage taken of the high insulation properties of the roof to turn the space covered by the roof into a passive heat collector that can used to heat an associated main building space. Potentially a conservatory can be used to collect much greater amounts of heat energy than a solar roof panel fitted to the roof of a house. A typical conventional conservatory loses the majority of its heat through the roof. The U value of a conventional conservatory roof is typically 3W/rn2. As described above, the glazed roofs 80, 100, 120, 130 can have a U value well below 1.0W/rn2. When the sun is low in the sky and shines through the east, west and south facing side windows of a conservatory in late autumn, winter or early spring, the heat equivalent of up to around 0.5KW/rn2 enters the conservatory.

For a conservatory glazed with conventional glazing panels, most of this heat goes to waste through the conservatory roof. In the case of a conservatory having a glazed roof such as the glazed roofs 80, 100, 120, 130, this heat cannot easily escape through the roof and becomes available to heat the house, or other connected building. There is no need for complex piping, heat recovery systems and similar such elements associated with solar panels and photo-voltaics. The solar heat collected in the conservatory can be liberated to the whole house by natural ventilation by simply opening the conservatory house door. The heat flow into the main building, and individual rooms within it, can be controlled by the extent to which the door to the conservatory and doors within the building are opened.

It will be appreciated that the features of the embodiments can be incorporated in new build glazed roofs or added to existing roofs by retrofitting. The inner glazing member supports 42, 44, 108 and extension members 112 are particularly suited to retrofitting to upgrade an existing roof and, for example, it will be understood that for a new build roof, features such as the support surfaces provided by the arms 50 of the inner glazing member supports 42, 44 or the ledges 106 provided by the inner glazing member supports 108 may be provided as integral parts of the glazing support members. It will also be appreciated that the inner glazing support members 42, 44, 108 are just examples of support structures that can be provided for the inner glazing members. For example, the inner glazing members may be supported by inner glazing member supports that are fitted to the sides 56 of the support bar 12. The fitting of such inner glazing member supports to the sides of the support bar 12 may be by any of the ways mentioned for fitting the inner glazing member support 108 to the extension member 112. It will also be understood, that the inner glazing support members could be an integral part of the extension members so that only one new part needs to be fitted to the glazing support members. Such an arrangement may be convenient even for new build roofs since it may be desirable to provide a basic glazing member support based on a traditional design and engineered for strength using a material that does not necessarily provide high thermal insulation and then fit a thermal insulating member or integral thermal insulating member and inner glazing member support device to the basic glazing member as a part of the build process or, alternatively, as a future upgrade.

Referring to Figure 2, as an example of retrofitting an inner glazing panel to an existing glazed roof, a glazed roof comprising the glazing support member 10 without inner glazing member supports 42 and with two glazing members 40 fitted to it should be imagined as the existing glazed roof. To upgrade the roof, the glazing bar cover 22 is first prised loose and then the glazing members 40 are removed. Inner glazing member supports 42 are then fitted onto the ledges 17 and inner glazing members 46 seated on the support surfaces defined by the arms 50 of the inner glazing member supports. The outer glazing members 40 are then replaced on the ledges 17 and associated gaskets 20 and the re-installation is completed by refitting the glazing bar cover 22. As a variation on this method, when the inner glazing members supports 42 are used, it may be possible to simply loosen the glazing members 40 by removing the glazing bar cover 22, insert the inner glazing member 46 from below the glazing member 40 and then slide the inner glazing member support 42 in behind the inner glazing member 46 and between the glazing member 40 and ledge 17. Alternatively, if the arm 48 is sufficiently thin, the flexibility provided by the elasticity of the gasket 2Oandlor flexibility of the glazing bar cover 22 may make it possible to simply slide the arm between the gasket and the outer glazing member. This process may be aided by pushing the outer glazing member away from the gasket 20 against the opposing force provided by the glazing bar cover.

Referring to Figure 4, as an example of retrofitting an inner glazing panel to an existing glazed roof, a glazed roof comprising glazing support members without inner glazing member supports 108 and extension members 112 should be imagined. In order to upgrade this glazed roof it is not necessary to interfere with the existing glazing members 102. The extension members 112 are first fitted to the support bars 12 of the glazing member supports and then the inner glazing members 104 are moved in behind the existing glazing members 102. The inner glazing member supports 108 are then fitted behind the inner glazing members 104. It will be appreciated that this system is particularly convenient since it does not require any operation on the existing glazing members, with the attendant risk of damage to the existing glazing members, gaskets and glazing bar covers, and the inner glazing members 104 can be quickly secured in place when the inner glazing member supports are secured to the glazing member supports by push-fit fastening.

In the embodiments, solar protection is provided by materials positioned in the cells of the cellular glazing sheets andlor between the glazing panels andlor the inner and outer glazing members. It is envisaged that where the glazing member comprises plastics glazing sheets, the heat absorbing andlor heat reflecting function may be obtained by incorporating suitable materials in the polymer structure of the glazing sheets. Thus, for example, a heat reflecting material in the form of, for example, a metal strip, metallised plastics laminate sheet or amorphous metal forms could be incorporated into the walls of the glazing sheet during an extrusion process.

Alternatively, suitable tints and dyes could be introduced to the plastics mix to absorb andlor reflect solar heat and light generally, or tailored to a specific solar heat (microwave/radiation) absorbing function.

It will be appreciated that the glazed roofs of the embodiments provide the possibility of much higher thermal insulation and acoustic insulation performance together with improved glare reduction and heat absorption as compared with conventional glazed roof structures. Thus a conservatory or the like using the glazed roofs of the embodiments can be made more comfortable in terms of solar protection and heating bills can be reduced. There is also the possibility of capturing the solar heat that is prevented from passing through the glazed roof and using it to provide heating to a designated area of a building attached to the glazed roof.

Plastics roof glazing requires periodic upgrading and replacement. This can be done on site, either with pre-prepared glazing members or by assembling the glazing members on site and then fitting the additional glazing members opposite the existing glazing members. Of course, it is possible an upgrade may also include replacing existing panels. As an alternative to fitting the additional glazing members inwardly of the existing glazing members, they could be fitted externally as illustrated by the glazed roof 130. This may make upgrading existing glazed roof structures curved sections, such as industrial barrel roofs, easier as the curve on the additional glazing member will not need to be so tight. It will be appreciated that when the additional glazing members are to be added externally to form an external additional glazing layer, the inner glazing member supports', may need to be reconfigured andlfitted at different locations to those shown in the illustrated embodiments.

When upgrading a glazed roof comprising glazing support members 10 and glazing bar covers 22, or similar structures, the additional glazing layer could be secured to the existing structure by fitting an additional glazing bar support and glazing bar cover to the existing members. For example, if the additional glazing layer is to be fitted externally of the existing glazing layer, a glazing bar support 10 would be secured, for example by screws, to each glazing bar cover 22 of the existing structure.

Alternatively, if the additional glazing layer is to be fitted internally of the existing glazing layer, a glazing bar support 10 would be fitted, for example by screws, to the underside of each existing glazing support bar. This may be advantageous in that it allows the possibility of using available glazing bar support and cover stock. It will also be understood that combing two glazing bar support and glazing bar cover sets in this way is not limited to upgrading work and could be applied to new build glazed roofs.

It will be understood that the glazing support members described with reference to the drawings are given purely by way of example and the invention is not limited to glazing support members having a snap on glazing bar cover, or indeed, two-part glazing member supports.

It will be appreciated that embodiments of the glazed roof provide the possibility of the conversion of glazed areas into passive solar heaters. In summer, up to 0.8KW/ m2 of heat enters the through the roof of a conservatory. In winter, when the sun is lower in the sky, up to 0.5KW/rn2 of heat enters through the side windows. The embodiments allow the collection of some of this heat to provide a heat source for the domestic or commercial premises.

In cases in which the glazed roofs are used to harvest solar energy, it may be desirable to locate a heat reflector or reflectors, which may be transparent or translucent, inwardly of the glazing members in order to reflect any solar energy not absorbed in the first pass through the glazing members.

It will be appreciated that when configuring a glazed roof, account will have to be taken of the amount of light that the roof is to transmit as well as the insulation, heat capture and heat reflection capabilities described above and in some cases, it may be necessary to balance optimising those capabilities and obtaining sufficient light transmissibility for a desired application.

In the embodiments, there are two glazing layers, which preferably comprise glazing panels andlor glazing sheets such as those shown in Figures 7 and 8. It will be appreciated that while not presently preferred, the glazed roofs may comprise more than two glazing layers if desired, particularly where the glazing panels andlor glazing sheets are made of plastics materials.

The embodiments have been described with particular reference to glazing installations in the form of glazed roofs. However, it is to be understood that the invention is not limited to roofs and features of the described embodiments may be incorporated in glazing installations generally and, for example, in glazed walls.

Claims

Claims 1. A glazed roof or wall comprising an outer glazing member supported by a glazing support frame and a separate inner glazing member disposed inwardly of and generally opposite said outer glazing member, said inner glazing member being supported by said glazing support frame.
2. A glazed roof or wall as claimed in claim 1, wherein said inner glazing member is supported by said support frame separately of said outer glazing member.
3. A. glazed roof or wall as claimed in claim 2, wherein said glazing support frame comprises a first glazing support member and a second glazing support member, said first and second glazing support members having respective ledge portions on which opposite edge regions of said outer glazing member are supported.
4. A glazed roof or wall as claimed in claim 3, wherein opposite edge regions of the inner glazing member are supported between said first and second glazing support members on respective inner glazing member support surfaces disposed between said ledge portions and respective innermost faces of said first and second glazing support members.
5. A glazed roof or wall as claimed in claim 4, wherein said first and second glazing support members each have an extension member fitted thereto, said extension members being arranged to increase the depth of the first and second glazing members and defining the innermost faces of the extended depth first and second glazing support members.
6. A glazed roof or wall as claimed in claim 5, wherein said extension members are thermally insulating extension members having a higher insulation value than the first and second glazing support members to which they are fitted.
7. A glazed roof or wall as claimed in claim 4, 5 or 6, wherein said inner glazing member support surfaces are provided by respective inner glazing member supports fitted to said first and second glazing support members.
8. A glazed roof or wall as claimed in claim 7, wherein said inner glazing member supports are secured to said first and second glazing support members by push-fit fastening.
9. A glazed roof or wall as claimed in claim 7 or 8, wherein said inner glazing member supports each have a secured portion that is sandwiched between the ledge portion of the respective first and second glazing support member and the edge region of the outer glazing member that is supported on the ledge portion.
10. A glazed roof or wall as claimed in claim 7 or 8, wherein said inner glazing member supports are secured to said innermost faces of the first and second glazing support members.
11. A glazed roof or wall as claimed in claim 3, wherein said inner glazing member is secured in abutment with respective innermost faces of said first and second glazing support members.
12. A glazed roof or wall as claimed in any one of the preceding claims, wherein said inner glazing member is spaced from said outer glazing member to define a space therebetween.
13. A glazed roof or wall as claimed in claim 12, comprising a spacer system disposed between and separating said outer glazing member and said inner glazing member.
14. A glazed roof or wall as claimed in claim 13, wherein said spacer system comprises a thermally andlor an acoustically insulating material.
15. A glazed roof or wall as claimed in claim 13 or 14, wherein said spacer system seals said space to define a sealed space between said inner and outer glazing members.
16. A glazed roof or wall as claimed in any one of claims 12 to 15, comprising a thermal andlor an acoustic insulating material disposed in said space between the inner and outer glazing members.
17. A glazed roof or wall as claimed in any one of claims 12 to 16, having a heat absorbing or heat reflecting material disposed in said space between the inner and outer glazing members.
18. A glazed roof or wall as claimed in any one of the preceding claims provided with at least one flowpath for an airflow for removing heat collected by the glazed roof or wall.
19. A glazed roof or wall as claimed in claim 18, wherein the or a said flowpath extends through at least one of said inner glazing panel and said outer glazing panel.
20, A glazed roof or wall as claimed in claim 19, wherein at least one of said inner and outer glazing panels is provided with a heat absorbing or heat reflecting material and an internal air space in which air is heated by heat absorbed by said heat absorbing material or heat reflected by said heat reflecting material, a said flowpath being arranged for said airflow to collect heat from said internal air space.
21. A glazed roof or wall as claimed in claim 18, 19 or 20 when dependent on any claim dependent on claim 12, wherein the or a said flowpath extends through said space.
22. A glazed roof or wall as claimed in claim 21, comprising at least one inlet port leading into said space and at least one outlet port leading from said space, said flowpath extending through said space extending between said ports.
23. A glazed roof or wall as claimed in claim 12 or any one of claims 13 to 17 when dependent on claim 12, comprising piping disposed in said space for conducting a fluid through said space for removing heat collected by said glazed roof or wall.
24. A glazed roof or wall as claimed in any one of the preceding claims having an insulation value substantially in the range 0.6 to 1.1 W/m2°C.
25. A glazed roof or wall as claimed in any one of the preceding claims, arranged to reject between 50% and 95% of solar heat received by the roof.
26. A conservatory having a glazed roof as claimed in any one of the preceding claims.
27. A method of upgrading a glazed roof or wall which glazed roof or wall comprises a glazing support frame and a plurality of existing glazing members supported by said glazing support frame to define an existing glazing layer, said method comprising fitting additional glazing members to said support frame generally opposite said existing glazing members to define an additional glazing layer.
28. A method of upgrading a glazed roof or wall as claimed in claim 27, wherein said additional glazing layer is disposed inwardly of said existing glazing layer.
29. A method of upgrading a glazed roof or wall as claimed in claim 28, wherein said glazing support frame comprises a plurality of glazing support members arranged to provide support for edge regions of respective said existing glazing members and said method comprising fitting respective extension members to said glazing support members inwardly of said existing glazing members to increase the depth of the respective glazing support members.
30. A method of upgrading a glazed roof or wall as claimed in claim 29, comprising fitting extension members that have a higher insulation value than said glazing support members.
31. A method of upgrading a glazed roof or wall as claimed in any one of claims 27 to 30, comprising fitting a plurality of glazing member supports to said support frame to support said additional glazing members.
32. A method of upgrading a glazed roof or wall as claimed in claim 31, comprising fitting said glazing member supports to said support frame by push-fitting.
33. A method of upgrading a glazed roof or wall as claimed in claim 31 or 32, comprising fitting said inner glazing member supports to innermost faces of the glazing support members.
34. A method of upgrading a glazed roof or wall as claimed in claim 31 or 32 when dependent on claim 29 or 30 comprising fitting said glazing member supports to said extension members.
35. A method of upgrading a glazed roof or wall as claimed in claim 31 or 32, comprising fitting a portion of each said glazing member support such that a portion of the glazing member support is trapped between an edge region of a said existing glazing member and an opposed portion of the respective glazing support member that supports said edge region.
36. A method of upgrading a glazed roof or wall as claimed in any one of claims 27 to 30, comprising fitting said additional glazing members in abutment with innermost or outermost surfaces of said glazing support frame.
37. A method of upgrading a glazed roof or wall as claimed in any one of claims 27 to 36, comprising fitting said additional glazing members to the support frame such that there is a space between each said additional glazing member and an opposed said existing glazing member.
38. A method of upgrading a glazed roof or wall as claimed in claim 37, comprising fitting spacers between the existing glazing members and opposed additional glazing members.
39. A method of upgrading a glazed roof or wall as claimed in claim 38, wherein said spacers comprise a thermally insulating and/or acoustically insulating material.
40. A method of upgrading a glazed roof or wall as claimed claim 37, 38 or 39, comprising providing at least one of the following materials at locations between said existing and additional glazing members: i) a heat reflecting material; S ii) a heat absorbing material; iii) a thermally insulating material; and iv) an acoustically insulating material.
41. A method of upgrading a glazed roof or wall as claimed in any one of claims 27 to 40, wherein said additional glazing members are multi-layer glazing sheets having internal spaces therein.
42. A method of upgrading a glazed roof or wall as claimed in any one of claims 27 to 41, wherein said additional glazing members comprise a plurality of glazing sheets arranged in opposed spaced apart relation to define an internal space therebetween.
43. A method of upgrading a glazed roof or wall as claimed in claim 41 or 42, wherein said additional glazing sheets include a heat reflecting or heat absorbing material for increasing the heat collecting capacity of the additional glazing sheets.
44. A method of upgrading a glazed roof or wall as claimed in claim 41, 42 or 43, comprising providing an air flowpath through said internal spaces of the additional glazing members for an airflow to collect heat from said internal spaces to provide a heated airflow.
45. A method of upgrading a glazed roof or wall as claimed in any one of claims 37 to 44, comprising providing an air flowpath through said spaces between the existing glazing members and said additional glazing members for an airflow to collect heat from said spaces to provide a heated airflow.
46. A method of upgrading a glazed roof or wall as claimed in any one of claims 37 to 45, comprising providing piping in said spaces between the existing and additional glazing members for conducting a fluid through said spaces for collecting heat from said spaces.
47. A method of upgrading a glazed roof or wall as claimed in any one of claims 27 to 46, comprising replacing said existing glazing members with replacement glazing members, said replacement glazing members comprising: i) a plurality of glazing sheets arranged in opposed spaced apart relation to define an internal space therebetween; or ii) a plurality of glazing sheets arranged in opposed spaced apart relation to define an internal space therebetween.
48. A method of upgrading a glazed roof or wall as claimed in claim 47, wherein said replacement glazing sheets include a heat reflecting or heat absorbing material for increasing the heat collecting capacity of the replacement glazing sheets.
49. A method of upgrading a glazed roof or wall as claimed in claim 47 or 48, comprising providing an air flowpath through said internal spaces of the replacement glazing members for an airflow to collect heat from said internal spaces to provide a heated airflow.
50. A method of upgrading a glazed roof or wall as claimed in claim 44, 45 or 49, comprising providing a receiver for a said heated airflow.
51. A kit for upgrading a glazed roof or wall which glazed roof or wall comprises a glazing support frame and a plurality of existing glazing members supported by said glazing support frame to define an existing glazing layer, said kit comprising a plurality of additional glazing members and a plurality of additional glazing member supports fittable to said support frame for supporting said additional glazing members in generally opposed relation to respective existing glazing members to define an additional glazing layer.
52. A kit for upgrading a glazed roof or wall as claimed in claim 51, wherein said support frame comprises a plurality of glazing support members, the kit comprising extension members for fitting to said glazing support members to increase the depth of said glazing support members.
53. A kit for upgrading a glazed roof or wall as claimed in claim 52, comprising a push-fit fastening system for making said extension members fittable to said glazing support members by push-fitting.
54. A kit for upgrading a glazed roof or wall as claimed in claim 51, 52 or 53, wherein said additional glazing member supports are adapted for push fit connection to the support frame.
55. A kit for upgrading a glazed roof or wall as claimed in claim 51, 52 or 53, wherein said additional glazing member supports are adapted to be fitted to said support frame by fitting a portion thereof between the support frame and an edge region of a said existing glazing panel.
56. A kit for upgrading a glazed roof or wall as claimed in any one of claims 51 to 55, comprising respective spacer systems for fitting between said additional glazing members and the opposed existing glazing members.
57. A kit for upgrading a glazed roof or wall as claimed in any one of claims 51 to 56, comprising at least one of: i) a heat reflecting material; ii) a heat absorbing material; iii) a thermally insulating material; and iv) an acoustically insulating material for fitting between said additional glazing members and the opposed existing glazing members.
58. A kit for upgrading a glazed roof or wall as claimed in any one of claims 51 to 57, wherein said additional glazing members comprise: i) a plurality of glazing sheets arranged in opposed spaced apart relation to define an internal space therebetween; or ii) a plurality of glazing sheets arranged in opposed spaced apart relation to define an internal space therebetween.
59. A kit for upgrading a glazed roof or wall as claimed in any one of claims 51 to 58, comprising piping for fitting in spaces defined between said existing and additional glazing layers.
60. A method of constructing a glazed roof or wall, the method comprising forming a glazing support frame, fixing a plurality of outer glazing members to said support frame to form an outer glazing layer, fixing a plurality of inner glazing members to said support frame separately of said outer glazing members to form an inner glazing layer.
61. A method of constructing a glazed roof or wall as claimed in claim 60, comprising fixing said inner and outer glazing members such that said inner and outer glazing layers are spaced apart.
62. A method of constructing a glazed roof or wall in claim 60 or 61, comprising providing at least one of: i) a heat reflecting material; ii) a heat absorbing material; iii) a thermally insulating material; and iv) an acoustically insulating material between said inner and outer glazing layers.
63. A method of constructing a glazed roof or wall as claimed in claim 60, 61 or 62, comprising defining an airflow path between said inner and outer glazing layers for collecting heat from between said inner and outer glazing layers by flowing air along said airflow path.
64. A method of constructing a glazed roof or wall as claimed in any one of claims to 63, comprising providing piping between said inner and outer glazing layers for collecting heat from between said inner and outer glazing layers by flowing a fluid along said piping.
65. A glazed roof or wall comprising a glazing support frame, a first glazing member layer supported by said glazing support frame, a second glazing member layer supported by said glazing support frame and at least one flow path for a fluid extending within said glazed roof or wall, said at least one flow path for a fluid being arranged such that a fluid flowing therein can be heated by solar heat collected within the glazed roof or wall to provide a heated fluid for output to an energy transfer apparatus.
66. A glazed roof or wall as claimed in claim 65, wherein said first and second glazing member layers are spaced apart and said at least one flow path for a fluid extends with the space between the spaced apart glazing member layers.
67. A glazed roof or wall as claimed in claim 66, wherein said at least one flow path for a fluid is defined by piping disposed in said space.
68. A glazed roof or wall as claimed in claim 66 or 67, wherein said glazed roof or wall is provided with a heat absorbing or heat reflecting material arranged to cause heat to be collected in said space.
69. A glazed roof or wall as claimed in any one of claims 65 to 68, wherein said at least one flow path is a part of a pressurised flow system arranged such that said heated fluid output is a gas or vapour.
70. A glazed roof as claimed in any one of claims 65 to 69 provided with an insulation for retaining said solar heat within the glazed roof or wall.
71. A glazed roof or wall as claimed in any one of claims 65 to 70, wherein said first and second glazing member layers each comprise a plurality of hollow cellular glazing sheets.
72. A glazed roof or wall substantially as herein described with reference to Figures 2 to 6 of the drawings.
73. A method of upgrading a glazed roof or wall substantially as herein described with reference to Figures 2 to 6 of the drawings.
74. A kit for upgrading a glazed roof or wall substantially as herein described with reference to Figures 2 to 6 of the drawings.