FR2506435A1 - Moulded fibre-cement support for solar energy reflectors - has moulded shell formed of asbestos fibres in cement binder on which reflecting surface is adhered - Google Patents

Abstract

The reflector shell is formed by moulding a fibrous material having a binder which is air permeable e.g. cement. The fibres are of asbestos and have the same coefficient of expansion as the reflecting surface, permitting the latter to be adhered to the shell. The combination of fibre and cement provides a high degree of resistance to ultraviolet radiation. The air permeability of the material allows moisture to evaporate as opposed to run between the shell surface and the reflector. Pref. sets of reflectors may be assembled from rows of profiles mounted on suitable racks which can pivot or tilt to maintain focal alignment w.r.t. the sun.

Description

 The invention relates to a solar collector comprising a reflector consisting of a rigid shell covered with a mirror and fixed to a support structure.

 Different types of solar collectors are known. Generally these have the purpose of concentrating the rays of the sun and are therefore made up, for this purpose, of a mirror of parabolic shape for example. Preferably, the mirror can be rotated in azimuth and on the baleen surface to stay pointed at the sun during the day.

 To this end, the reflecting surface is fixed to a shell itself mounted on a metal frame connected to a frame by a universal joint, the frame being provided with means for orienting the frame and therefore the shell.

 The shell must be rigid enough so that the reflective surface retains the desired shape over time. However, this shell should not be too heavy so as not to interfere with the orientation and tire the mechanisms. In addition, it is advantageous that the entire hull is made up of adjoining elements light enough to be handled by a man. Finally, for reasons of economy and ease of implementation, it is often preferred that the hull is made of a moldable material.

 We therefore had to produce shells in laminated material on which the reflective surface is bonded, this latter generally consisting, as well as the shell, of planar facets associated with one another.

The laminated material has several disadvantages. First of all, it is not extremely rigid. On the other hand, it was found that moisture could slip between the mirror and the hull and stagnate there, the
looks like two surfaces are waterproof /. This eventually results in a risk of deterioration of the silver in the mirror.

 This is why we have been led to seek to constitute the shell another material which does not have these drawbacks.

 According to the invention, the rigid support shell for the reflecting surface is formed by molding a product consisting of fibers capable of hanging between them and embedded in a binder permeable to air.

 Such a product consists for example of a fiber cement, the fibers being asbestos and the binder being cement.

 A shell thus constituted has a set of qualities which are not found in the materials used until now for this application.

 We first of all know that asbestos-cement makes it possible to produce fairly light and sufficiently rigid shells by molding and very economically.

 I1 is also found that asbestos-cement has la'prao priété to have a coefficient of expansion close to that of the mirror and in addition to constitute a surface very conducive to the bonding of the mirror by an adhesive. In addition, this product is perfectly rot-proof and very resistant to bad weather.

 It should also be noted that asbestos cement has a better behavior over time than most synthetic materials that exposure to Ultra-Violet rays can make brittle.

 Thus, thanks to this set of qualities, asbestos cement would already be suitable for constituting a rigid shell retaining the shape of the reflective surface for a long period of time in the open air.

These qualities are due in particular to the solidity and the excellent bonding between them of asbestos fibers. Furthermore, the cement which constitutes the binder between the fibers has the additional advantage of being breathable. As a result, a solid asbestos-cement shell, in addition to its rigidity qualities, has the advantage of allowing the evaporation of moisture which could have slipped between the shell and the mirror. Thus the quality of the silvering is maintained for much longer.

 Finally, asbestos-cement lends itself particularly well to the constitution of light, easy-to-handle elements each comprising a face on which the reflective surface is bonded and provided along its edges with ribs which can be fixed together by known means.

 The shell according to the invention therefore has a set of qualities which were not found in the materials used until now.

 Of course, the invention is not strictly limited to the products that have just been described, insofar as one could find other fibers having the strength and bonding qualities of asbestos and a another permeable binder like cement.

Claims (3)

 1.- Solar collector including a reflector. consisting of a rigid shell covered with a mirror and fixed on a support structure characterized in that the rigid shell is formed by molding a product consisting of fibers capable of hanging between them and embedded in a permeable binder with batten.  2.- solar collector according to claim 1, characterized in that the product forming the rigid shell consists of asbestos fibers bonded by cement.  3. Solar collector according to one of claims 1 and 2, characterized in that the hull consists of a plurality of elements joined together along assembly ribs.