Question

schematic of parabolic dish CSP plant ​

Answer 1

A parabolic dish reflector (PDR) is a point-focus system with a paraboloid geometry given by the revolution of one half of aparabola around its normal axis. Sunlight entering the collector aperture with a normal incidence is concentrated onto a heat receiver located at the focal point of the dish.

The easiest way is to cut and fold a flat sheet into a parabolic dish. Then glue a layer of aluminum foil on its inner surface, for reflectivity. The flat sheet can be as cheap as cardboard. However water resistant material, such as plastic or metal, will last longer.