Radiant energy absorbers

A solar energy absorber tube assembly for receiving and collecting radiant solar energy concentrated by a solar concentrator, said absorber tube assembly comprising a fluid flow absorber tube, said absorber tube having a tubular wall, said wall having an outer surface arranged to be exposed in use to said concentrated solar energy, an inner hollow tubular member arranged coaxially within said absorber tube and defining with said absorber tube, a longitudinally extending annular space, helically extending barrier means provided within said annular space and defining a helically extending flow passage within said space for the passage of a fluid through said absorber tube assembly, and a feed tube for supply of fluid to said helically extending flow passage, said feed tube being located coaxially within said inner tubular member and spaced therefrom to define an insulating space to insulate inward flow through said feed tube from outward flow through said helically extending flow passage.

Solar energy concentrating apparatus including at least one solar concentrator and an absorber tube assembly for receiving radiant solar energy concentrated by said solar concentrator, said absorber tube assembly comprising a fluid flow absorber tube having an outer surface adapted to be exposed to said concentrated solar energy, a first inner tubular member arranged coaxially within said absorber tube and defining therewith an annular space, a helical separator in said annular space defining a helical flow passage extending along said absorber tube assembly, and a second tubular member arranged within said first tubular member and spaced therefrom, said second tubular member defining a feed tube for supplying fluid to said helical flow passage, and wherein the space between said feed tube and second tubular member defines an insulating space insulating flow through said feed tube from flow through said helical flow passage.

A method of generating superheated steam, said method including the steps of:

• providing radiant solar energy concentrating apparatus comprising a plurality of solar energy concentrators, absorber tube assemblies associated with each concentrator to receive concentrated solar energy therefrom, each said absorber tube assembly comprising a fluid flow absorber tube, a first inner tubular member arranged coaxially within said absorber tube and defining therewith an annular space, a helical separator in said annular space defining a helical flow passage extending along said absorber tube assembly, and a second tubular member arranged coaxially within said first tubular member and spaced therefrom, said second tubular member defining a feed tube for supplying water and/or steam to said helical flow passage, said absorber tube assemblies of respective solar energy concentrators being connected in series, and
• supplying water to said series of absorber tube assemblies, said water being heated and converted into steam and said steam being heated into super-heated steam in passage through respective absorber tube assemblies.