Observation and modeling of irradiance near water surface of a photovoltaic pond

Accurate evaluation of near ground solar radiation in photovoltaic (PV) covered areas is essential for controlling adverse environmental effects and comprehensively utilizing the earth's surface resources. The irradiance near the water surface of a photovoltaic fishpond was measured with eighteen distributed pyranometers. A simplified penetration model is proposed to reveal the shielding effect of PV panels on direct and diffuse irradiance. The model can well capture the spatial-temporal variation of the global irradiance due to the shielding effect of PV arrays. Numerical results show that proper modeling of the shading effect on diffuse irradiance is essential for the calculation accuracy of the cumulative global irradiance loss for various weather types and sky-view restriction levels. The spatial variation range of global radiation penetration ratio under the PV panels is 10%-90%. The spatially-averaged monthly shielding effects show that the maximum (87%) and minimum (46%) relative irradiance loss ratios in the studied PV area occur in December and June, respectively.