Empirical Modeling of Optimum Tilt Angle for Flat Solar Collectors and PV Panels

Abstract Global historical experimental measurements regarding temporal and geographical variations of sky clearness index worldwide and their associated diffused light estimations are used to model the optimum tilt angle between a flat solar collector, or a PV solar panel and the horizontal for all latitudes within both hemispheres. Equations for the yearly, seasonal and monthly relations between optimum tilt angle and latitude angle are obtained. General good agreements between this modeling results and most of both experimental and other models predictions are found. A freely downloadable MATLAB software that output yearly, seasonal and monthly optimum tilt angle for any latitude is made available.