Abstract: A solar collector comprisesA. a multiplicity of tubes to pass fluid and to receive heat, andB. channel shaped heat transfer members having flanges, the members having webs interconnecting the flanges and presented to receive solar radiation,C. the tubes clamped between and in heat transfer contact with flanges on successive of said members to form a tube and member assembly, whereby the solar heated channel members transfer heat via the tube clamping flanges to the tubes.