During the last decade we developed solar collectors from optical design, deeply analysed using ray tracing simulations, to realisation and test. Several optical layouts have been considered: linear concentrators, as well as, lens configurations with increased complexity from simple parabolic collectors to lens mirror combinations [1-7]. Our solar concentrators are designed to be applied in the Photo Voltaic sector or in the thermal field.

The studies presented in this paper analyse a trough collector with parabolic profile, whose characteristics and performance have been examined by ray tracing simulations. The major components of the solar trough are linear mirror and linear absorber in Fig. 1. The linear parabolic mirror
concentrates the sunlight over the absorber represented by a metal pipe, surrounded by a glass tube. The configuration parameters considered in this paper are:

■ Linear parabolic mirror

— Focal length: f = 780 mm.

— Dimensions of collector aperture:

— Width W = 1.8 m;

— Length L = 5 m.

■ Linear Absorber

— Dimensions of metal pipe:

— External diameter D = 50 mm;

— Length L = 5 m.

— Dimensions of glass tube:

— External diameter G = 70 mm;

— Thickness T = 2 mm;

— Length L = 5 m.

The first study describes an original methodology to reproduce rigid deformations of the linear parabolic mirror. Successively it analyses how much these mirror deformations affect the energy collected by the solar trough. The second study examines the interactions between mirror deformations, misalignment and tracking errors. The optical characteristics considered in this paper are: mirror edge deformation, collection efficiency, misalignment angle and acceptance angle.