Example (a) in Fig. 8 shows a thermosiphon collector with blow-moulded absorber of PE. (b) and (c) are flat-plate collectors with 10 mm PC twin-wall sheets as collector cover. In example (b) is

the absorber made of silicone rubber tubing partly compressed between metal plates. A drain-back collector with stiff, extruded absorber plate of polyphenylene ether/polystyrene (PPE/PS) blend is shown in (c). Example (d) is a solar air collector of PC where the extruded structure has a transpar­ent surface as collector cover and a black rear side as absorber. A transparent, hollow roof tile of polymethyl methacrylate (PMMA) was developed as solar collector with a black liquid as absorber and heat carrier (e). Example (f) represents a hybrid absorber of EPDM pipes pressed into a metal, modular roof system with omega-shape profile; it is available with/without glazing and as a hybrid PV/solar thermal collector. The examples (c), (d) and (f) in Fig. 8 are modular systems of poly­meric or hybrid-polymeric collectors, which are available in various lengths and designed for re­placing conventional roof — or facade covers.