D. Fontani 1*, P. Sansoni 1, F. Francini 1, D. Jafrancesco 1, G. Chiani 2, M. De Lucia

1 CNR-INOA Istituto Nazionale di Ottica Applicata, Largo E. Fermi 6 — 50125 Firenze — Italy
2 Dip. Energetica — CREAR, Univ. di Firenze, Via Santa Marta, 3 — 50139 Firenze — Italy
* Corresponding Author, daniela. fontani@inoa. it

Abstract

A linear parabolic mirror for sunlight concentration has been analysed and simulated. The study examines the geometrical deformations of the parabolic profile and their effects on solar light collection. The application is a solar trough, whose parabolic mirror has been optically designed to concentrate the sunlight on a cylindrical receiver.

The analysis procedure is based on the use of a mathematical representation for parabolic and deformed profiles. The mathematical approach consists in introducing conic constant and conic equation to represent the mirror profiles. This methodology to replicate the deformations of a parabolic mirror is simple and efficient. But the most interesting result is that it seems to reproduce the flexibility of a real solar collector and its imperfect rigidity.

The optical simulations allow controlling all the optical parameters; nevertheless collection efficiency and acceptance angle are probably the most important for our application. The optical characteristics have been monitored to evidence how much they are affected by geometrical deformations of the mirror profile. Finally the mirror deformation effect has been combined to alignment and tracking errors.

Keywords: optical project, ray tracing, deformations.