Receiver tube with receiver tubular jacket and parabolic trough collector containing same

A receiver tube (2) for a parabolic trough collector, said parabolic trough collector comprising a parabolic mirror (1) having a focal point (F) and a normal axis (N), which is arranged outside of said receiver tube so as to direct reflected light from the parabolic mirror on said receiver tube;

• wherein said receiver tube is arranged at said focal point (F) of said parabolic mirror and comprises an absorber tube (4) and a tubular jacket (3) arranged around the absorber tube (4);
• wherein said tubular jacket (3) comprises a glass tube and structural elements (9a, 9b, 9c, 9d);
• wherein said structural elements (9a, 9b, 9c, 9d) comprise a plurality of lenses, prisms and/or polyhedral elements and said structural elements (9a, 9b, 9c, 9d) extend around said tubular jacket at least over respective angular ranges of 20° to 65° on opposite sides of said normal axis (N);
• whereby said structural elements focus sunlight that falls directly from the sun on the receiver tube (2) but which would otherwise be deflected away from the absorber tube without the presence of said structural elements and focus sunlight that is reflected from the parabolic mirror (1) but which would otherwise not reach said absorber tube without the presence of said structural elements on said absorber tube arranged in the tubular jacket.

A parabolic trough collector for solar energy, said parabolic trough collector comprising

• a parabolic mirror (1) having a focal point (F) and a normal axis (N);
• and
• a receiver tube (2) arranged at said focal point (F), said parabolic mirror (1) being arranged outside of said receiver tube (2) so that said normal axis (N) passes through said receiver tube (2);
• in which said receiver tube (2) comprises a tubular jacket (3) and an absorber tube (4) arranged in the tubular jacket (3), said tubular jacket comprises a glass tube and structural elements (9a, 9b, 9c, 9d) that defract and/or deflect light, said structural elements comprising a plurality of lenses, prisms and/or polyhedral elements;
• and
• in which said structural elements (9a, 9b, 9c, 9d) extend around said tubular jacket at least over respective angular ranges of 20° to 65° on opposite sides of said normal axis (N);
• whereby said structural elements (9a, 9b, 9c, 9d) are arranged around said tubular jacket so as to focus solar radiation that falls on the receiver tube directly from the sun but which would otherwise be deflected away from the absorber tube without the presence of said structural elements on the absorber tube and so as to focus solar radiation that is reflected from the parabolic mirror (1) but which would otherwise not reach said absorber tube without the presence of said structural elements on said absorber tube arranged in the tubular jacket.