Light management materials angular response testing and certification

Light management materials (e.g. round wires, structured ribbons or films) contribution, by specular reflection, to PV module’s Isc is strongly dependent by radiation direction respect to the module cover sheet plane (the module plane) [1] [2] [3] [4] [5] [6]. Light management materials reflective surfaces are tilted, not coplanar, respect to the module plane, so radiation Angle of Incidence on light management materials depends both on Angle of Incidence and Azimuth Angle on the module plane. As stated in the IAM procedure introduction text of the IEC 61853-2 (2016 edition), in long standing mainstream PV module bill of materials, the main contribution to the angular response is given by far from the front cover (e.g. glass ARC), dependent exclusively by radiation Angle of Incidence on the module plane. Current angular response standard protocol, based on the Incidence Angle Modifier (IAM) test, is well positioned for Angle of Incidence-dependent angular response characterization, not for Angle of Incidence and Azimuth Angle dependent one. In this paper is proposed a test, Hemispherical IAM, for robust characterizations of any kind of PV module and light management material. Further, the aim of the paper is outlining a procedure, overcoming following issues: 1) upgrade of the IAM test non-destructive measurement method; 2) a new Adaptive Protocol for the Hemispherical IAM, designed to ensure a controlled balance between an adequate measurements discretization but still keeping viable workload and costs; 3) a new two-tier certification system: a) light management materials certified characterization by material manufacturer, then to be used in b) commercial modules certification, enabling for each light management complexity a proper accuracy but still avoiding test redundancy.