Measure of the solar flux conveyed onto a lambertian target by a novel bi-axial fresnel concentrator

This paper deals with the optical analysis of a prototype of a novel concentrator, named as Bi-Axial Fresnel (BAF). This concentrator aims at reducing production and installation costs, as well as keeping as low as possible the weight and the bulk of the mirrors field, making it suitable for building small-dimensions systems, able to be placed on industrial roofs, as an example. The prototype is composed as an array of 3x3 mirrors. Its theoretical concentration is therefore 9. The experiment made use of a very basic equipment, which included a thermal flux sensor and a simple webcam, properly equipped for distinguish grey scales under quite high solar intensities. The concentrator was governed by an Arduino card, while the acquisition took place by means of a National Instruments acquisition board and Labview software. The aim of this experimental setup was the reconstruction of the solar flux on a fixed Lambertian target, based on the grey-scale maps gathered through the webcam and properly scaled accordingly to the punctual solar flux measured by the sensor. This way, the experimental apparatus was able to get an estimation of the solar power conveyed to the target.