Calculation of Irradiance from Illuminance for Artificial Light Photovoltaics Applications

Many indoor sensors are powered by artificial-light-harvesting photovoltaic (PV) cells. The performance evaluation and application of PV devices require irradiance measurement to determine input power. Standard solar irradiance meters provide measurements calibrated to sunlight spectra and do not have the low-light-level capability needed for indoor applications. Light meters, specifically designed for human visible artificial light applications, measure illuminance. This article describes a low-cost method to calculate irradiance from illuminance measurement of artificial light sources. An application example is provided.