Solar collectors

A solar collector including an absorber having at least one channel for conducting a fluid receiving the heat absorbed, a housing enclosing the absorber and having radiation-transparent windows covering and spaced from both faces of the absorber, and partition members disposed between the absorber and the housing and effective to block the circulation of air flowing in the space between one face of the absorber and the housing from flowing to the space between the other face of the absorber and the housing, to thereby reduce convection losses from the absorber.