Abstract: The invention relates to an elongated absorber arrangement for a trough collector, which is subjected to concentrated radiation over its length during operation, and which has means for transporting heat-transporting fluid through the absorber arrangement. The absorber arrangement has at least one fluid-free absorber space for concentrated radiation, which has a thermal opening leading into its interior and walls for absorption of the heat incident into it.

Abstract: The invention relates to a trough collector with a primary concentrator, which concentrates solar radiation into a focal line region, with an arrangement for secondary concentration of the solar rays reflected by the primary concentrator, which arrangement concentrates the solar rays further into focal point regions. The arrangement for secondary concentration has a plurality of rows of secondary concentrators which have identical orientation in a row, but have differing orientation from row to row. Further, means are provided in order to keep one of the rows in the operating position and the other rows in a rest position. Thus, a range of the skew angle can be assigned to each of the rows and in the event of the change thereof, another row is brought into operating position.