Benchmarking clear sky and transposition models for solar irradiance estimation on vertical planes to facilitate glazed facade design

Authors: Debayan Paul, Giuseppe De Michele, Behzad Najafi, Stefano Avesani

The present study aims to benchmark the models utilized for estimating the solar irradiance on vertical planes that can facilitate the determination of critical conditions, which are utilized in the glazed facade design. Accordingly, in the first part of the study, the performance of PVGIS databases for Europe for estimating the solar irradiance components on the horizontal surfaces is compared with the on-site measurements at Bolzano airport (Italy). It is demonstrated that PVGIS-SARAH estimates both the global and diffuse solar irradiance components, compared to on-site measurements, with an acceptable error range ( 2–5%). The accuracy of isotropic and anisotropic transposition models is then compared for the same location, which demonstrates that the isotropic model tends to underestimate the global vertical incident irradiance by 6–12% of the daily peak value, while an agreement between the estimations of the anisotropic Perez model and the measurements is observed.

Open access paper here.