Multi-tube solar collector structure

A linear Fresnel collector comprising a stationary collector structure that is arranged to be located at a level above a field of reflectors and to receive solar radiation reflected from reflectors within the field, the collector structure comprising an inverted trough having an aperture and an enclosing window and, located within the trough, a plurality of longitudinally extending absorber tubes that are arranged to carry a heat exchange fluid, each absorber tube having a diameter that is small relative to the aperture of the trough through which the tubes are illuminated, and the absorber tubes being supported side-by-side in coplanar fashion within the trough with some of said absorber tubes being located along margins of the inverted trough, wherein the collector structure is configured such that a portion of heat exchange fluid within the collector structure and having a lower temperature than other of the heat exchange fluid within the collector structure is directed through said tubes located along the margins of the inverted trough.