Analysis of the radiation flux profile of the 100 sun Prometeo facetted dish concentrator

All PV systems have cells or groups of cells connected in series in order to build up voltage and minimise current. Because current is almost linearly dependent on the incident light, the current in a string of identical solar cells will be limited by the cell with the least illumination. It is therefore important to achieve a flux profile as uniform as possible. Typically for dish concentrators this is achieved through the use of secondary flux modifiers which disperse light at the centre of the receiver more evenly. However, for a facetted dish such as the Prometeo, in theory the flux profile at the focus should be uniform. In practice it is costly to achieve highly accurate optics for a dish system, due to the need for both a tightly toleranced mirror support structure and a precise solar tracking system. The aim for the Prometeo system is to lower costs by using simple materials that can be manufactured without the need for precision tooling, and at the same time, to achieve a consistent flux profile on the whole PV receiver. In this paper the measured and simulated flux profiles are compared, and the results are discussed.