Solar concentrators with curvature determined by gravity and a variable density distribution

Distributions of variable density have been analyzed which can be applied on the surface of solar concentrators with curvature determined by gravity so as to obtain maximum theoretical concentration along a present focal axis. A simple method to obtain in practice distributions of variable density is proposed and, consequently, an analysis is carried out of improvements in the factor of concentration and of the energy gathered by the collector in respect of solar concentrators with curvature determined only by gravity. (author)