Measurement uncertainty in the profile detection on solar troughs

Surface profile control on solar concentrators is fundamental since the mirror can be imperfectly manufactured. Optical profilometric measurements are generally addressed to detect small localised irregularities. The paper presents an optical profilometer for linear solar collectors, which are typically employed in thermal plants and more recently in concentrating photovoltaic systems. The profilometer includes a source of parallel rays and a target placed at the collector focal distance. It was developed simulating profile measurements on linear parabolic mirrors; then the method was validated by tests on a practical realisation. The device examines the reflector surface operating on a plane transversal to the linear collector axis; then the detection is repeated displacing the optical profilometer along the collector axis. This experimentation allowed to deeply examine and reduce the errors of the measurement procedure.