Measurement and modeling of diffuse irradiance masking on tilted planes for solar engineering applications

Photovoltaic and solar thermal projects require accurate irradiance data models for the design, assessment, forecasting of power output. For panels collectors installed in arrays, view toward sky ground is restricted by surrounding rows. This paper analyzes impact obstructions on diffuse distribution fixed-tilt addressing insufficient research coverage to date. Irradiance was measured using high-precision pyranometers placed at ten positions throughout an experimental collector array 3.5 6 m row spacings 30°, 37.5°, 45° tilt angles (relative between 0.68 1.51). A novel anisotropic transposition model developed calculate tilted along height, accounting masking due obstructions. The also solved inversely, obtaining local global horizontal from irradiance. validation showed that accurately captures distinct shape distribution. Results indicate a strong effect narrow steep angles. most extreme configuration (3.5 spacing, angle, 1.67 relative spacing), reduced 64% bottom 89% average, top collector. As consequence, measurements can result biased performance assessments.