Mapping Solar Flux Distribution in Parabolic Trough Collectors to Assess Optical Performance

Abstract

This paper describes the development and testing of a novel device capable of mapping the flux distribution in parabolic trough solar collectors (PTCs). Accurate knowledge about the flux distribution is essential in any concentrated solar power (CSP) application, in particular PTCs equipped with concentrator photovoltaic (CPV) cells, since their efficiency highly depends on the collector’s light focusing properties. However, the assessment of CSP collectors’ optical performance requires sophisticated measurement technology, as the error budget of any sun-tracking optical device comprises a variety of factors ranging from physical properties such as mirror reflectivity to mechanical aspects like gravity sag and play in gears. The presented approach features a scanner consisting of a CPV cell mounted on a pair of linear actuators. A thorough state of the art analysis was conducted and numerous technological approaches were assessed. Design aspects such as component selection, cooling, and data acquisition are discussed and finally exemplary measurement results are presented.