GB2280503A

GB2280503A - Solar energy glazing systems and methods

Info

Publication number: GB2280503A
Application number: GB9415151A
Authority: GB
Inventors: Frederick Brian Mckee
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-07-28
Filing date: 1994-07-27
Publication date: 1995-02-01
Anticipated expiration: 2014-07-27
Also published as: GB9415151D0; WO1995004006A1; GB9315584D0; AU7347394A; GB2280503B

Abstract

A glazing system is provided having two or are generally parallel panes or panels (13, 40) housed within a vented framework (11, 12, 19 - 22) to provide at least one vented air-space (15) therebetween. At least one of the panes or panels (40) is adapted to absorb solar energy and thereby 'heat' the air contained within the air-space (15) to cause convection currents therein. Inlet vents (20, 22) and outlet vents (19, 21) are respectively disposed above and below each of the panes or panels (13, 40) and by appropriate control of these it is possible to use the convection currents within the air-space (15) to vent air into or out of the building interior or to vent the air-space (15) externally of the building to cool the said at least one pane or panel (40). Preferably the invention provides for the coating or doping of glazing panels or a fluid filled solar panel (40) the combined optical transmission qualities of the constituent parts of which peat transmission of light highly visible to the human eye, but which provide absorption of solar energy outside that spectrum. <IMAGE>

Description

SOUR ENERGY GLAZING SYSTEMS AND METHODS This invention relates to solar energy glazing systems and use thereof generally and more particularly, but not exclusively, to solar energy glazing adapted to transmit therethrough only useful wavelengths of solar energy and/or to distribute by convection/conduction heat absorbed by panels of the glazing.

One of the major problems with large buildings is to reduce the heat gain due to incident solar and other energy incident on the building.

Also, it is often desirable to reduce the heat escaping from the building in cold periods. One solution is to use heavily tinted or reflective glass often as part of a double-glazing system. Tinted glass tends to be heated by incident solar radiation thereby radiating that energy into the building at wavelengths uninhibited by the tinting agent. Reflective glass may not be aesthetically pleasing and during winter months the reflected energy could more usefully be used for heating the building interior.

In addition tinted and reflective glazing greatly restricts the visible natural daylight entering the building. This often necessitates the use of electrical lighting in day-time even during summer nonths.

It is an object of the invention to provide an improved form of glazing.

According to one aspect of the invention there is prodded a vented window apparatus comprising a frame housing in spaced apart relationship a first pane of generally transparent glass or plastics and a first heat absorbing panel to define an air-space therebetween, having disposed above said first pane a first closable outlet vent, below said first pane a first closable inlet vent, above said first panel a second closable outlet vent and below said first system or panel a second closable inlet vent, with the arrangement providing that solar energy absorbed by said first panel and/or first pane can be ressved by convection of air through the air-space when one, other or both of said first inlet vents is or are open and one, other or both of said first outlet vents is or are open.

Said first panel may be exposed internally of the building and said first pane exposed externally of the building.

The first panel may be transparent or translucent or opaque.

The first panel may be thermally insulated fran the interior of the building.

The frame preferably houses a second pane of generally transparent glass or plastics or a second heat absorbing panel to define a second air-space therebetween, having disposed above said second pane or panel a third outlet vent and below said second pane, panel or system a third inlet vent. Either or both of said third inlet and outlet vents are preferably closable.

According to another aspect of the invention there is provided a glazing system coMprising a pane of transparent or translucent material and a doping agent and/or coating agent the combined optical characteristics of the system providing solar energy transmission therethrough having a transmission curve closely approximating the photopic response function CIE 18(E-1.2)1970 of the human eye.

According to yet another aspect of the invention there is provided a glazing system coMprising a pane of generally transparent or translucent material and a doping agent and/or coating agent applied to one surface of the pane the combined optical characteristics of which permit light transmission through the system of the majority of wavelengths of solar energy visible to the human eye and which provide for absorption by the glass and the coating of the majority of solar energy invisible to the human eye.

The doping agent and/or coating agent may be pthylocyanine.

The pthylocyanine preferably has a concentration in a range equivalent to 40 and preferably approximately 80 ppm in aqueous solution.

In accordance with yet another aspect of the invention there is provided a solar energy collecting panel comprising two panes of glass or generally transparent plastics and at least one fluid passageway therebetween with a solution of dyestuff contained within the passageway, with the arrangement providing that the combined optical characteristics of the panel provide solar energy transmission therethrough having a transmission curve closely approximating the photopic response function CIE 18(E-1.2)1970 of the human eye.

In accordance with yet another aspect of the present invention there is provided a solar energy collecting panel comprising two panes of glass or generally transparent plastics and at least one fluid passageway therebetween with a solution of dyestuff contained within the passageway, with the arrangement providing that the combined optical characteristics of the panel permit light transmission through the panel of the majority if not all wavelengths of solar energy visible to the human eye and which provide for absorption by the glass and the coating of the majority of solar energy invisible to the human eye.

The dyestuff is preferably water soluble pthylocyanine, preferably in a concentration in the range of 30 to 200 ppm and more preferably 60 to 80 ppm. Preferably the concentration is in the order of 40 ppn.

In accordance with yet another aspect of the present invention there is provided vented window apparatus comprising a frame housing in spaced apart relationship a first pane of generally transparent glass or plastics and a first glazing system in accordance with the above definition or a first solar panel in accordance with the above definition to define an air-space therebetween, having disposed above said first pane a first closable outlet vent, below said first pane a first closable inlet vent, above said first system or panel a second closable outlet vent and below said first system or panel a second closable inlet vent, with the arrangement providing that solar energy absorbed by said first pane, system or panel can be removed by convection of air through the air-space when one, other or both of said first inlet vents is or are open and one, other or both of said first outlet vents is or are open.

In accordance with yet another aspect of the present invention there is provided a method of heating a building having apparatus in accordance with the inmediately preceding paragraph with said first pane exposed internally of the building and said first panel or glazing system exposed externally of the building, wherein said second inlet vent is open, said first outlet vent is open and said other vents are closed to warm the building with air fran outside the building, said second inlet and outlet vents are closed and said first inlet and outlet vents are open to warm the building with air circulated fran inside, or both of said inlet vents are open, said first outlet vent is open and said second outlet is closed.

In accordance with yet another aspect of the present invention there is provided a method of cooling or preventing solar heating of a building having apparatus in accordance with the penultimate paragraph above having said first pane exposed internally of the building and said first panel or glazing system exposed externally of the building, wherein said first inlet vent is open, said second autlet vent is open and said other vents are closed to vent air fran the building, said first inlet and outlet vents are closed and said second inlet and outlet vents are open to cool the apparatus with air circulated fran outside the building, or both of said inlet vents are open, said first outlet vent is closed and said second outlet is open.

In accordance with yet another aspect of the present invention there is provided a vented window apparatus comprising a frame housing in spaced apart relationship a first pane of generally transparent glass or plastics and a first glazing system in accordance with the above definition or a first solar panel in accordance with the above definition to define an air-space therebetween, having disposed above either said first pane or said first systemlpanel a closable outlet vent and below either said first pane or said first system/panel a closable inlet vent, with the arrangement providing that solar energy absorbed by said first pane, system or panel can be removed by convection of air through the air-space when the two vents are open.

In accordance with yet another aspect of the present invention there is provided a vented window apparatus catprising a frame housing in spaced apart relationship a first pane of generally transparent glass or plastics and a first glazing system in accordance with the above definition or a first solar panel in accordance with the above definition to define an air-space therebetween, having disposed above either said first pane or said first system/panel an outlet vent and below either said first pane or said first system/panel an inlet vent, with the arrangement providing that solar energy absorbed by said first pane, system or panel can be removed by convection of air through the air-space.

Preferably the frame houses a second pane of generally transparent glass or plastics, a second glazing system in accordance with the above definition or a first solar panel in accordance with the above definition to define a second air-space therebetween, having disposed above said second pane, panel or system a third outlet vent and below said second pane, panel or system a third inlet vent. Either or both of said third inlet and outlet vents are prferably closable.

Preferably said first pane is replaced by either a further glazing system in accordance with the above definition or a further solar panel in accordance with the above definition.

In accordance with yet another aspect of the invention a glazing system comprises a pane of transparent or translucent material and a doping agent and/or coating agent the combined optical characteristics of the system providing solar energy transmission therethrough having a transmission curve closely approximating the photopic response function CIE 18(E-1.2)1970 of the human eye.

In accordance with yet another aspect of the invention a glazing system ccnprises a pane of transparent or translucent material and a doping agent and/or coating agent applied to one surface of the pane the combined optical characteristics of which permit light transmission through the system of the majority of wavelengths of solar energy visible to the human eye and which provide for absorption by the glass and the coating of the majority of solar energy invisible to the human eye.

The doping agent and/or coating agent may be pthylocyanine and may have a concentration in a range equivalent to between 40 and preferably approximately 80 part in aqueus solution.

In accordance with yet another aspect of the invention a solar energy collecting panel comprises two panes of glass or generally transparent plastics and at least one fluid passageway therebetween with a solution of dyestuff contained within the passageway, with the arrangement providing that the combined optical characteristics of the panel provide solar energy transmission therethrough having a transmission curve closely approximating the photopic response function CIE 18(E-1.2)1970 of the human eye.

In accordance with yet another aspect of the invention a solar energy collecting panel coMprises two panes of glass or generally transparent plastics and at least one fluid passageway therebetween with a solution of dyestuff contained within the passageway, with the arrangement providing that the combined optical characteristics of the panel permit light transmission through the panel of the majority if not all wavelengths of solar energy visible to the human eye and which provide for absorption by the glass and the coating of the majority of solar energy invisible to the human eye.

The dyestuff may be water soluble pthylocyanine which may have a concentration in the range of 30 to 200 ppm, preferably in the range of 60 to 80 ppm. It may have a concentration in the order of 40 ppm.

Ehtodiments of the invention will now be itore particularly described by way of example only and with reference to the accompanying drawings, in which:- Figure 1 is a graphical representation of 'black body' radiation of the sun and the photopic response function of a human eye; Figure 2 is a graphical representation of the photopic response function also shown in Figure 1, the transmission response of typical float glass, and the relative solar response of an embodiment of the invention; Figure 3 is a vented window apparatus in accordance with a first ertibodiitent according to one aspect of the invention; Figure 4 is a vented window apparatus in accordance with a second e=bcdinent of the invention with similar parts to those of said first Embodiment shown in Figure 3 being denoted by like numbers; Figure 5 is a vented window apparatus in accordance with a third embodiment of the invention similar to the embodiment shown in Figure 3 with like parts being denoted by like numbers. and Figure 6 is a vented window apparatus in accordance with another aspect of the invention.

The optical transmission characteristics of most transparent or translucent glazing materials can be defined by reference to their visible light transmission (LT), energy absorption (era) and solar shading coefficient (SC). Desirably a glazing system should have high LT, high EA and low SC which would permit transmission of high natural daylight and low transmission of solar energy. However, solid materials having high Ek usually mean that the glazing also acts as a radiator thus effectively increasing SC. Because of their broad spectral characteristics, most window/cladding elements of glazing systems cannot exhibit the aforedescribed desirable combination of high LT, high Ek and low SC.

Typical values for reflective glass are:- LT 10%, Ek 60%, SC 0.26 Typical values for tinted glass are:- LT 72%, Ek 49%, SC 0.72 Typical values for clear float glass are:- LT 87%, EA 15%, SC 0.95 Hitherto, glass inanufacturers have assumed that high LT, high EA and low SC in the same material is physically impossible. The inventor considers this assumption to be based on the false premise that the human photopic response curve in the visible spectrum has the same profile as the solar transmission curve within that spectrum. As can be seen from Figure 1 that is not the case. Graph 1 is the internationally agreed photopic function CIE 18(E-1.2)1970 and graph 2 represents black body solar radiation.

In Figure 1 the chain lines at 'a' and 'd' illustrate the half power band width 510 to 610 milli-microns wavelength on curve 1, i.e. of the human eye. chain lines at 'A' and 'B' indicate the full response of the typical human eye i.e. between 360 and 830 millimicrons.

Although the response of the human eye extends between 360 to 830 millimicrons the major part of its sensitivity is in the aforementioned 'half power band' width of electmagnetic theory with a maxImum at 555 millimicrons. At sea level the solar spectrum extends fran 200 to 30,000 millimicrons with most of the energy within the range 240 to 2000 millimicrons. It will be appreciated that daylight within the 'half band power width' between 'a' and 'b' is of particular value to human sight and the remaining wavelengths can be considered redundant for that purpose and provide unwanted solar energy in summer and valuable heating in winter.

A material or cattination of materials having negligible reflection that matched the sensitivity function of the eye (particularly in the wavelength range 510 to 610 millimicrons) would have desirable optical characteristics having approxinate values of LT in the visual spectrum of 89%, EA of 89% ad SC of 0.11. Such would appear glass clear but almost totally absorbing of the aforementioned redundant wavelengths of solar energy. Self-evidently with such a high degree of absorption the material or ccibination would tend to get 'hot' and radiate absorbed energy in the infrared bandwidth thus effectively degrading the SC. In one embodiment of the invention described hereinafter a catbination of materials is suggested having the aforementioned desirable characteristics. Whilst in the embodiments illustrated in Figures 3 to 5 'cooling' means described hereinafter are provided which will maintain a generally low temperature for said material or combination thus obviating the otherwise degrading effect on the SC thereof.

By appreciating that it is the combined transmission response of glass, coating and/or doping materials which is of inportance, the inventor has suggested in one embodiment of his invention that a pane of float glass (not shown) be coated with a dye such as pthalocyanine at a suitable concentration to provide a solar response curve similar to that shown as curve 3 in Figure 2. In that Figure the curve 1 corresponds to the photopic response curve in Figure 1 and curve 4 is the transmission response curve of typical float glass.

In another embodiment a glazing unit (not shown) is in the form of two parallel panes of float glass separated by at least one channel carrying an energy absorbent cooling fluid. Preferably, the panes are 6itrn thick separated by a 6mm fluid filled gap. The fluid is a water solution of pthalocyanine dye having a concentration of 40 ppm giving the response curve 3. This provides for combined characteristics LT in the human visual spectrum of approximately 60%, ER of about 74% and SC 0.07. A concentration of 200 ppm would give the undesirable characteristics of LT 16%, EA 94% and SC 0.07. It will be appreciated that the liquid used could be caused to circulate externally of the glazing unit to be dissipated elsewhere in summer and for heating purposes in winter, for example.

By appropriate choice of glazing materials, coating/doping agents and/or coolant carposition, and physical dimensions and configuration it is possible to achieve characteristics better approxImating curve 1. The choice of coolant and/or coating/doping agent can be made by appropriate mathematical analysis of the transmission characteristics of the energy source (the sun at the desired latitude), the ambient atrnosphere, the glass composition and the human eye. It will be appreciated that dyestuffs may be added to achieve any desired colouring effects.

The aforedescribed embodiments provide for glazing systems which improve on existing solar energy systems using darkened glass and/or coolant fluids to achieve high RA. They also enable natural daylighting of buildings without enormous air-conditioning costs which makes them particularly useful in nfilti-storey structures. If errnxnurents using coolant are employed heat fran the coolant may be extracted by suitable heat exchangers or heat-pumps. If these are placed in a suitable area of the building, such as the well of a staircase, which will act as a flue then the upward movement of air can be used to ventilate floors of the building. In large buildings such air mcvement could be used to drive air-turbine generators during the night, for example In the embodiment illustrated in Figure 3 a vented window apparatus 10 comprises a framework having an upper beam 11 and lower beam 12 and a pair of sheets of float glass panes 13,14 held in parallel spaced apart relationship to define an air-space 15 therebetween. The first pane 13, adapted to be disposed inwardly of a building to which the frame 1 is fitted, is a sheet of plain float glass which may have its outwardly disposed surface 16 coated with a low emissivity or long wavelength reflective agent. Said other pane 14 is typically in accordance with the aforesaid one ewtodiment of the invention wherein its inwardly disposed surface 17 or outwardly disposed surface 18 is coated with a suitable agent or agents. Both surfaces 17,18 could be coated. Alternatively, the glass of pane 14 could be doped and may also be coated with a suitable agent or agents. Consequently, it is the said other pane 14 which is mostly responsible for the solar energy absorption of the apparatus 10.

The apparatus 10 also comprises a plurality of vents. Disposed above and below the first pane 13 are respectively closable outlet vent 19 and inlet vent 20 which can permit the interior/inside of the building to communicate with the air-space 15. Similarly to permit communication with the exterior/outside of the building outlet vent 21 and inlet vent 22 are disposed respectively above and below said other pane 14.

Energy absorbed by said other pane 14 will heat air within the air-space 15. Controlled operation of vents 19 to 21 will allow convection to force mcrvernt of air between inlet and outlet vents that are open.

Consequently, by appropriate operation of the vents, it is possible to vent that air externally or internally of the building using air from either the interior, exterior or both interior and exterior of the building.

Alternatively, by closing all vents the glazing apparatus 10 performs as conventional double glazing. Different permatations of vent closure and opening permit variously heating, cooling and/or ventilation of the interior.

The first pane 13 will tend to remain at a low temperature approximating the ambient interior room temperature. This pane 13 could be coated with a thermotropic or therwnstromic material that would autatatically reduce the light transmission as it heated thereby further reducing the transmission of solar energy. Also, so long as the pane 13 remains 'cool' electro-optical and photo-chromic devices that automatically vary visible light transmission can be attached to the surfaces thereof.

Advantageously, the pane 13 remaining 'cool' avoids the incidence of thermal problems often associated with the aforesaid devices.

It will be appreciated that energy absorbed by said other pane 14 will also be lost to the exterior/outside of the building. In colder climates, or those having hot summers and extremely cold winters, this may not be desirable. The vented window apparatus 30 illustrated in Figure 4 overcomes this disadvantage by providing in addition to panes 13,14 an outer pane of float glass 31 to provide a further air-space 32. The pane 31 is provided with inlet and outlet vents 33,34 respectively for use in venting the interior and for cooling of the interior during summer months.

In winter months the vents 33,34 when closed permit the air-space 32 to be vented internally of the building. Alternatively, vents 21,22,33 and 34 can be closed so that panes 18 and 31 provide conventional double glazing. It will be understood that the double glazing will result in the temperature within air-space 32 rising above the ambient external temperature thereby reducing heat loss from pane 18 into that air-space.

The operation and function of the embodiment shown in Figure 5 is essentially the same as that of Figure 3. However, instead of a coated exterior pane (pane 14 in Figure 3) this embodiment is provided with a solar panel 40 comprising an inner pane of float glass 41 disposed in spaced apart relationship to an outer pane of float glass 42 to define a coolant channel 43 therebetween. The solar panel 40 is in the form of the aforedescribed said another embodiment.

Figure 6 illustrates a vented window or wall apparatus 50 in accordance with another aspect of the invention. The apparatus 50 comprises a frame housing in spaced apart relationship clear glass panes 51, 52 and optionally a third pane 53 which define an air-space 54 or air-spaces 54,55 vented as those in aforedescribed tibocients. In this embcdinent pane 51 could be replaced by an opaque and/or thermally insulated sheet and pane 52 could be replaced by thermal unit such as that denoted 40 in Figure 5 or a coated/doped pane as aforedescribed. The apparatus could be used for forced venting of the interior or for heating the interior where illumination was not desired.

It will be appreciated that the aforedescribed venting need not have the illustrated configuration(s). For example, vents could be provided within the associated framework. Alternatively, the framework could be provided with inlet and outlet ports leading to controllable valve means. Also, if the internal pressure of the building is varied relative to atmospheric pressure then many more modes of heating, cooling and 'natural' ventilation could be achieved. Also, it is possible that by provision of suitable ducting air could be blown into the appropriate air-space(s) and if desired thereafter directed to any part of the building or to atmosphere.

Where solar panels such as that denoted 40 in Figure 5 are used, the coolant/heat absorbing liquid may be pumped via heat exchangers or heat-pumps to remote parts of the building, e.g. fran a sunny to a shaded side of the building.

Claims

CCAB5:

1. A vented window apparatus comprising a frame housing in spaced apart relationship a first pane of generally transparent glass or plastics and a first heat absorbing panel to define an air-space therebetween, having disposed above said first pane a first closable outlet vent, below said first pane a first closable inlet vent, above said first panel a second closable outlet vent and below said first system or panel a second closable inlet vent, with the arrangement providing that solar energy absorbed by said first panel and/or first pane can be rewcved by convection of air through the air-space when one, other or both of said first inlet vents is or are open and one, other or both of said first outlet vents is or are open.

2. Apparatus in accordance with claim 1, wherein said first panel is exposed internally of the building and said first pane is exposed externally of the building.

3. Apparatus in accordance with claim 2, wherein the first panel is transparent or translucent.

4. Apparatus in accordance with claim 2, wherein said first panel is opaque.

5. Apparatus in accordance with claim 3 or claim 4, wherein the first panel is thermally insulated from the interior of the building.

6. Apparatus in accordance with any one of the preceding claims, wherein the frame houses a second pane of generally transparent glass or plastics or a second heat absorbing panel to define a second air-space therebetween, having disposed above said second pane or panel a third outlet vent and below said second pane, panel or system a third inlet vent.

7. Apparatus in accordance with claim 6, wherein either or both of said third inlet and outlet vents are closable.

8. A vented window apparatus substantially as hereinbefore described and as illustrated in Figure 6 of the accompanying drawings.

9. A glazing system canprising a pane of transparent or translucent material and a doping agent and/or coating agent the combined optical characteristics of the system providing solar energy transmission therethrough having a transmission curve closely approximating the photopic response function CIE 18(E-1.2)1970.

10. A glazing system comprising a pane of generally transparent or translucent material and a doping agent and/or coating agent applied to one surface of the pane the combined optical characteristics of which permit light transmission through the system of the majority of wavelengths of solar energy visible to the human eye and which provide for absorption by the glass and the coating of the majority of solar energy invisible to the human eye.

11. A glazing system in accordance with claim 9 or claim 10, wherein the doping agent and/or coating agent is pthylocyanine.

12. A glazing system in accordance with claim 11, wherein the pthylocyanine has a concentration in a range equivalent to 40 and preferably approximately 80 ppn in aqueous solution.

13. A solar energy collecting panel comprising two panes of glass or generally transparent plastics and at least one fluid passageway therebetween with a solution of dyestuff contained within the passageway, with the arrangement providing that the combined optical characteristics of the panel provide solar energy transmission therethrough having a transmission curve closely approximating the photopic response function CIE 18(E-1.2)1970.

14. A solar energy collecting panel cm arising two panes of glass or generally transparent plastics and at least one fluid passageway therebetween with a solution of dyestuff contained within the passageway, with the arrangement providing that the combined optical characteristics of the panel permit light transmission through the panel of the majority if not all wavelengths of solar energy visible to the human eye and which provide for absorption by the glass and the coating of the majority of solar energy invisible to the human eye.

15. A solar panel in accordance with claim 13 or claim 14, wherein the dyestuff is water soluble pthylocyanine,

16. A solar panel in accordance with claim 15, wherein the pthylocyanine has a concentration in the range of 30 to 200 ppn.

17. A solar panel in accordance with claim 15, wherein the pthylocyanine has a concentration in the range of 60 to 80 ppm.

18. A solar panel in accordance with claim 15, wherein the pthylocyanine has a concentration in the order of 40 ppm.

19. A vented window apparatus comprising a frame housing in spaced apart relationship a first pane of generally transparent glass or plastics and a first glazing system in accordance with any one of claims 9 to 12 or a first solar panel in accordance with any one of claims 13 to 18 to define an air-space therebetween, having disposed above said first pane a first closable outlet vent, below said first pane a first closable inlet vent, above said first system or panel a second closable outlet vent and below said first system or panel a second closable inlet vent, with the arrangement providing that solar energy absorbed by said first pane, system or panel can be removed by convection of air through the air-space when one, other or both of said first inlet vents is or are open and one, other or both of said first outlet vents is or are open.

20. A method of heating a building having apparatus in accordance with claim 19 with said first pane exposed internally of the building and said first panel or glazing system exposed externally of the building, wherein said second inlet vent is open, said first outlet vent is open and said other vents are closed to warm the building with air fran outside the building, said second inlet and outlet vents are closed and said first inlet and outlet vents are open to warm the building with air circulated fran inside, or both of said inlet vents are open, said first outlet vent is open and said second outlet is closed.

21. A method of cooling or preventing solar heating of a building having apparatus in accordance with claim 19 having said first pane exposed internally of the building and said first panel or glazing system exposed externally of the building, wherein said first inlet vent is open, said second outlet vent is open and said other vents are closed to vent air from the building, said first inlet and outlet vents are closed and said second inlet and outlet vents are open to cool the apparatus with air circulated from outside the building, or both of said inlet vents are open, said first outlet vent is closed and said second outlet is open.

22. A vented window apparatus comprising a frame housing in spaced apart relationship a first pane of generally transparent glass or plastics and a first glazing system in accordance with any one of claims 9 to 12 or a first solar panel in accordance with any one of claims 13 to 18 to define an air-space therebetween, having disposed above either said first pane or said first system/panel a closable outlet vent and below either said first pane or said first systemlpanel a closable inlet vent, with the arrangement providing that solar energy absorbed by said first pane, system or panel can be removed by convection of air through the air-space when the two vents are open.

23. A vented window apparatus comprising a frame housing in spaced apart relationship a first pane of generally transparent glass or plastics and a first glazing system in accordance with any one of claims 9 to 12 or a first solar panel in accordance with any one of claims 13 to 18 to define an air-space therebetween, having disposed above either said first pane or said first system/panel an outlet vent and below either said first pane or said first systenlpanel an inlet vent, with the arrangement providing that solar energy absorbed by said first pane, system or panel can be removed by convection of air through the air-space.

24. Apparatus in accordance with claim 19, claim 22 or claim 23, wherein the frame houses a second pane of generally transparent glass or plastics, a second glazing system in accordance with any one of claims 9 to 12 or a first solar panel in accordance with any one of claims 13 to 18 to define a second air-space therebetween, having disposed above said second pane, panel or system a third outlet vent and below said second pane, panel or system a third inlet vent.

25. Apparatus in accordance with claim 24, wherein either or both of said third inlet and outlet vents are closable.

26. Apparatus in accordance with claim 19 or any one of claims 21 to 25, wherein said first pane is replaced by either a further glazing system in accordance with any one of claims 9 to 12 or a further solar panel in accordance with any one of claims 13 to 18.

27. A vented window apparatus substantially as hereinbefore described and as illustrated in Figure 3, Figure 4 or Figure 5 of the accompanying drawings