IMPROVED ACCURACY FOR LOW-COST SOLAR IRRADIANCE SENSORS

ABSTRACT: Accurate measurements of broadband (full spectrum) solar irradiance are fundamental to the successful implementation of solar power systems, both photovoltaic and solar thermal. Historically, acceptable measurement accuracy has been achieved using expensive thermopile-based pyranometers and pyrheliometers. The measurement limitations and sensitivities of these expensive radiometers are a topic that has been addressed elsewhere. This paper demonstrates how to achieve acceptable accuracy (±3%) in irradiance measurements using sensors costing less than one-tenth that of typical thermopile devices. The low-cost devices use either silicon photodiodes or photovoltaic cells as sensors, and in addition to low-cost, have several operational advantages