Collector

The concentrator has a trough configuration. The collector will exploit a revolutionary concept based on flexible pneumatic mirrors; by applying a few Pascal of overpressure over a plastic foil (in this case, polyester with a reflective aluminized mirror coating on one side), a perfectly cylindrical curved surface may be obtained. By overlapping a few foils it is possible to create a multi arc pneumatic mirror approaching the shape of a perfect parabola.

A low refraction long lasting transparent ETFE foil on one side and a silicon fiberglass fabric on the other side will form a kind of pillow, with the mirror foil being well protected inside. It is then inflated with air at a few mbar pressure. The result is a 2-volume pillow: the upper volume given by the ETFE and the mirror; and the lower volume resulting from the mirror and the silicon fabric.

By applying a slight pressure, different between the two volumes, it is possible to stretch the mirror foil perfectly, so it which will deform elastically into its position. This pressure difference is achieved by using ventilators, and the overpressure is regulated by modifying their speed. The membranes are supported on their edge with a simple pre-cast and pre-stressed concrete frame having a rectangular shape.

The structure, although slightly less efficient due to losses at the interface with the ETFE foil, is much more rigid and stronger than a conventional metallic trough and results in consistently lower costs per square meter.

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