GB905760A - Improvements in or relating to apparatus for utilizing radiant energy - Google Patents

Abstract

<PICT:0905760/III/1> <PICT:0905760/III/2> A solar still, for distilling water, has a radiation inlet opening with a transparent cover which is so roughened on one or both of its surfaces that the reduction in the amount of entering radiation is less than the increase in energy retained in the apparatus. The peaks in the roughening number from 1000 to 4000 per linear inch the spacing being several times larger that the maximum energy wavelength of the radiation from inside the apparatus. Roughening. Thins is effected by sand-papering, sand-blasting, treating with a slurry of quartz and water, embossing undulations, or coating with particles of mica, quartz or glass. Preferably the roughening is only on the inner surface. Cover materials. The preferred material is polyvinyl fluoride film but the following may be used; glass; laminated films; open scrim glass fabric impregnated with polytetrafluoroethylene; polytetra-fluoroethylene; copolymers of the latter with hexafluoropropane, monochlorotrifluoroethylene, vinylidene chloride and vinyl fluoride, or polyethylene terephthalate; polyethylene; polyvinyl butyral or chloride; copolymers of vinyl chloride with styrene, acrylonitrile or vinylidene chloride and vinylacetate; homopolymers and copolymers of vinylidene chloride. Solar stills (Figs. 2 and 3). An envelope is formed consisting of a batt 2 of black polyacrylonitrile fibres lightly tacked by adhesive 5 to a lower layer 3 of polyvinyl fluoride film the edges of which are sealed to a cover layer 1 of the same material which is roughened on its inner surface. This envelope is laid on a slightly inclined insulating base 6 between upper and lower supply and discharge channels 16, 15 for salt water communicating with the interior of the envelope so that batt 2 is saturated, a constant level being maintained by weirs 12 transverse to the incline. Several envelopes are disposed side by side between concrete dividers 7 having grooves in which the edges of the envelopes are fixed by wedges 14. Channels 10 in the edges of the envelopes collect the pure water condensate from the inner surface of layer 1 and supply it to header 9 through pipes 8. The envelopes are inflated by air after assembly.ALSO:Apparatus, e.g. a greenhouse, solar generator, solar heater or solar still, for using radiation such as solar radiation has a radiation inlet opening with a transparent cover which is so roughened on one or both of its surfaces that the reduction in the amount of entering radiation is less than the increase in energy retained in the apparatus. The peaks in the roughening number from 1,000 to 4,000 per linear inch the spacing being several times larger than the maximum energy wavelength of the radiation from inside the apparatus. Roughening. This is effected by sand-papering, sand-blasting, treating with a slurry of quartz and water, embossing undulations, or coating with particles of mica, quartz or glass. Preferably the roughening is only on the inner surface. Cover materials. The preferred material is polyvinyl fluoride film but the following may be used; glass; laminated films; open scrim glass fabric impregnated with polytetrafluoroethylene; polytetrafluoroethylene; copolymers of the latter with hexafluoropropane, monochlorotrifluoroethylene, vinylidene chloride and vinyl fluoride, or polyethylene terephthalate; polyethylene; polyvinyl butyral or chloride; copolymers of vinyl chloride with styrene, acrylonitrile or vinylidene chloride and vinylacetate; homopolymers and copolymers of vinylidene chloride.