GB2142951A

GB2142951A - A solar collection system

Info

Publication number: GB2142951A
Application number: GB08410047A
Authority: GB
Inventors: Michael Douglas Novels; Martin Love
Original assignee: ENERGY SECRETARY OF STATE FOR; UK Secretary of State for Energy
Current assignee: ENERGY SECRETARY OF STATE FOR; UK Secretary of State for Energy
Priority date: 1983-04-18
Filing date: 1984-04-18
Publication date: 1985-01-30
Also published as: GB8410047D0

Abstract

A solar collection system for the roof of a building is provided by a solar collector plate which is spaced from the roof, a transparent cover above the plate, and foam insulation moulded in situ to the roof and in which the solar collector plate and the edges of the cover are embedded. <IMAGE>

Description

SPECIFICATION A solar collection system This invention relates to a solar collection system and to a method of incorporating the system on the roof of a building to heat or preheat water from solar energy incident on the system.

The design, installation, and economic aspects of solar collection systems in the United Kingdom are described in "Solar Heating Systems for the UK" by S. J. Wozniak, 1979, published by HMSO, London, England. In a simple form of solar collection system, water is arranged to circulate through a solar collector plate which is blackened or coated to improve the absorption of solar energy. Further heat loss is inhibited by locating the plate in a box with heat insulative material under the plate, and a glass or transparent plastics lid above the plate. Proprietory solar collector plates have been devised by companies such as: TI Research Laboratories, Hinxton Hall, Hinxton, Saffron Walden, Essex, CB10 1 RH, England, or Olin Corporation, East Alton, Illinois, USA.

As solar collection systems are but one of the alternative energy systems that use natural energy sources such as solar, wave, or wind power, the adoption of solar collection systems depends to a large extent on economic criteria, and an important factor in the economics of solar collection systems is that of fabrication and installation costs which are a function of the design of the solar collection system used.

The invention therefore provides in one aspect, a solar collection system for the roof of a building and comprising, a solar collector plate, a transparent cover for the plate, a mounting extending from the plate and for holding the cover above the plate such that portions of the cover extend beyond the mounting, and foam insulation moulded in situ so as to adhere to the roof, and into which foam insulation the plate, the mounting, and the extended portions of the cover are embedded.

In another aspect, the invention provides a method of installing a solar collection system on the roof of a building, the method comprising, locating a solar collector plate on the roof such as to define a space between the plate and the roof, mounting a transparent cover above the plate such that extended portions of the cover extend beyond the mounting, and injecting foam insulation into said space and about the sides of the plate and the mounting, and about the extended portions of the cover, so as to embed the plate, the mounting, and the extended portions, in the foam insulation and bond the foam insulation to the roof.

Preferably, the cover is dome shaped, and sealing means locate between the cover and the mounting.

In order to improve resistance to displacement of the foam insulation from the roof, keying members locate under cladding members of the roof and have a portion thereof embedded in the foam insulation.

Anchorage means may extend from the underside of the collector plate into the foam insulation.

Preferably, the foam insulation comprises an isocyanurate foam, and the cover comprises polycarbonate. Advantageously, a clear polyvinyl fluoride sheet is applied to the exterior of the cover by heat shrinkage. In order to protect the foam insulation from the effect of ultraviolet light, a protective coating of a synthetic rubber paint may be applied thereto.

The invention will now be further described by way of example only with reference to the accompanying drawings, in which: Figure 1 shows a perspective representation of part of a roof having a solar collection system thereon; Figure 2 shows to an enlarged scale a fragmentary sectional view on the line ll-ll of Figure 1; Figure 3 shows to an enlarged scale a sectional view on the line Ill-Ill of Figure 2; Figure 4 shows to an enlarged scale a fragmentary view in the direction of arrow A of Figure 2; Figure 5 shows a sectional view on the line V-V of Figure 4;; Figure 6 is a sectional view illustrating the initial stage of the installation of the solar collection system of Figure 1 on the roof, and Figure 7shows a fragmentary sectional view to an enlarged scale of a later stage of the installation of the solar collection system Referring now to Figure 1, part of a house roof 10 is shown comprising, interlocking and overlapping tiles 12 supported on battens (not shown) between trussed rafters 14. A solar collection system 20 is installed on the roof 10, and as shown in more detail in Figure 2, comprises a solar collector plate 22 anchored to an isocyanurate foam insulation base 24. The base 24 is bonded to the tiles 12, and is also anchored thereto by the use of a number of metal hooks (see Figure 3), each hook 26 having a tongue portion 28 which fits under a respective tile 12 and a hook portion 29 embedded in the base 24.Referring again to Figure 2, a domed transparent, UV stabilised polycarbonate cover 30 rests on a rubber sealing member 32 which is supported buy a raised flanged portion 34 of the collector plate 22, the cover 30 extending downwardly beyond the flanged portion 34 at 36 where the cover 30 is embedded in the base 24.

The solar collector plate 22 as shown in Figures 4 and 5, comprises a serpentine, stainless steel tube 40 embedded in an aluminium panel 42 having ribs 44 which stiffen the panel 42 and reduce the overall thermal expansion of the panel 42. Both sides of the plate 22 are treated with a black matt paint to increase the thermal absorptivity of the plate 22. 'L' shaped members 50 extend from the underside of the panel 42 to anchor the plate 22 more firmly in the base 24, and four channel section spacers 52 are secured to the corners at the underside of the panel 42 by screws (not shown) and support the plate 22 on the roof 10 before the base 24 is installed. In order to reduce thermal loss from the plate 22 to the roof 10, a rubber gasket 54 is inserted between each spacer 52 and the panel 42.Drainage pipes 46 for condensate extend from the plate 22, and an inlet pipe 48 for cold water and an outlet pipe 49 for warm water connect at the respective ends of the serpen tine tube 40 and extend through the roof (not shown in Figure 5) to connect with a storage tank (not shown) in the house.

In use of the solar collection system 20, cold water from the house is circulated through the tube 40 where it is heated by the solar energy absorbed by the plate 22, and warm water discharged through the outlet pipe 49 is fed to the storage tank and used for domestic purposes in the house.

The solar collection system 20 is readily installed on the roof 10. As shown in Figure 6, the plate 22 with the cover 30 in place is positioned on the roof 10. A sheet 56 of polythene is placed over the cover 30 and under a soft rubber base 57 of a three-sided mould 58 about the plate 22, and enables an isocyanurate foam insulation, such as a methane di-isocyanate isocyanurate (e.g. Isofoam RM606 supplied by the Baxenden Chemical Company, Accrington, Lancashire BB5 2SL) to be injected through the open side of the mould 58 and under the polythene sheet 56 from a gun 59 of a foam application machine (not shown). The mould 58 and the polythene sheet 56 are then removed and replaced as shown in Figure 7 by a four-sided mould 64 with a soft rubber base 66, and foam insulation is injected around the sides of the solar collection system 20 from the gun 59 to form the base 24.In order to facilitate removal of the mould 64, a suitable aerosol wax release agent may be applied to the inside surface of the mould 64to inhibit adhesion thereto of the foam insulation.

Extreme care must be taken when injecting the foam insulation because of the toxic nature of the components of the isocyanurate foam and, therefore, manufacturers instructions must be strictly observed. Subsequently the exterior of the foam insulation base 24 is protected from the effect of ultraviolet light by appiication of a synthetic rubber paint such as Futuraflex 875, and a synthetic rubber sealing component is applied to the interface between the outside surface of the foam insulation and the roof 10.

A clear polyvinyl fluoride sheet (not shown) (e.g.

Dupont Tedlar PVF sheet) may be attached to the cover 30 by heat shrinkage before the cover 30 is fitted to the solar collection system 20, to reduce the amount of ultraviolet light incident on the cover 30 and also to protect the cover 30 from abrasion. The cover 30 is conveniently made by vacuum forming or blow moulding from an extruded polycarbonate sheet having outer skins separated by webbing. It will be understood, however, that where desired suitable alternative materials may be used in the construction of the components of the solarcollec- tion system.

Claims

1. A solar collection system for the roof of a building and comprising, a solar collector plate, a transparent cover for the plate, a mounting extending from the plate and for holding the cover above the plate such that portions of the cover extend beyond the mounting, and foam insulation moulded in situ so as to adhere to the roof, and into which foam insulation the plate, the mounting, and the extended portions of the cover are embedded.

2. A solar collection system as claimed in claim 1 wherein the cover is dome shaped, and sealing means locate between the cover and the mounting.

3. A solar collection system as claimed in claim 1 or claim 2, wherein keying members locate under cladding members of the roof and have a portion thereof embedded in the foam insulation.

4. A solar collection system as claimed in any of the preceding claims, wherein anchorage means extend from the underside of the collector plate into the foam insulation.

5. A solar collection system as claimed in any of the preceding claims, wherein the foam insulation comprises an isocyanurate foam, and the cover comprises polycarbonate.

6. A'solar collection system as claimed in any of the preceding claims, wherein a clear polyvinyl fluoride sheet is applied to the exterior of the cover by heat shrinkage.

7. A method of installing a solar collection system on the roof of a building, the method comprising, locating a solar collector plate on the roof such as to define a space between the plate and the roof, mounting a transparent cover above the plate such that extended portions of the cover extended beyond the mounting, and injecting foam insulation into the said space and about the sides of the plate and the mounting, and about the extended portions of the cover, so as to embed the plate, the mounting, and the extended portions, in the foam insulation and bond the foam insulation to the roof.

8. A solar collection system substantially as herein described with reference to, and illustrated in, the accompanying drawings.

9. A method of installing a solar collection system substantially as herein described with reference to Figures 6 and 7 of the accompanying drawings.