Solar energy concentrating and collecting arrangement

A solar energy concentrating and collecting arrangement in which a plurality of laterally adjacent partial cylindrical oblong concave reflector-concentrators form the roof of a house, school or other building, particularly a heat utilization building, with a corresponding plurality of ganged movable collectors movably supported in spaced relation above and along the length of the oblong roof/reflectors. Each roof/reflector-concentrator has at least three radii, for enabling accommodation of wide variations of the sun angles during the various seasons of the year and during each day of a given season, while still affording a desired concentration of solar energy on the collector. The roof/reflector-concentrators are preferably substantially symmetrical in curvature and width about a vertical central plane, and face vertically upward to form an inverted modified cycloid-like surface.