Analysis of Composite Stretched-Membrane Heliostats

Abstract

The stretched-membrane concept has the potential for reducing the cost of heliostats used for solar thermal energy generation in central receiver systems. In this concept, a high strength/structural membrane carrying the reflective film is stretched uniformly on a toroidal frame. The resulting structure has high stiffness and is structurally efficient. It is practically suitable for composite materials, since the loading is primarily in-plane. In this paper, the application of composite materials to stretched-membrane heliostat design is investigated. The results of the analysis show that composite materials for both the membrane and the frame exhibit significant advantages over metals. These include high strength-to-weight design, higher resistance to wind-induced deformation, the possibility of independently tailoring bending and torsional stiffness, and better transportability.