Low-cost, open-hardware shadow band system for diffuse irradiance measurements

In this work, we present the design, implementation, and test of a low-cost, open-hardware shadow band system that enables a pyranometer to measure global and diffuse irradiance. This system was implemented in Lima, Peru, and experimentally tested by contrasting it with a commercial reference system consisting of two pyranometers, one blocked by a shadow ring. The developed shadow band system automatically opens and closes to measure the global and diffuse irradiance consecutively, respectively, without requiring regular, manual adjustments of the shadow ring position as in the reference system. Thus, it potentially saves costs on equipment to characterize de irradiance components. Initial measurements in Lima indicate 100#x00025; and at least 23#x00025; of diffuse irradiance under cloudy and clear sky conditions, respectively.