Abstract: A heat collector and radiator for allowing the absorption of lower atmosphere radiation by the maximizing of the surface area capable of absorbing the diffuse radiation. A plurality of closely spaced tubular elements are disposed in parallelism with relatively narrow web portions interconnecting the adjacent tubular elements and in tangential relationship therewith. The structure is unitarily formed from a polymer material admixed with carbon black or like additive. A header means at each opposite end of the tubular elements/web portions communicates therewith. The structure is selective in the respect that it has an emissivity lower than absorptivity, and is less effected by the incident angle.