Assessing the dynamics of indoor natural illuminance in adavanced packages for building energy analysis

Advanced packages for building energy analysis require simplified methods to reduce the computational time in assessing the indoor visual environment. The paper develops and compares some simplified calculation procedures for a quick assessment of the minimum indoor natural illuminance on the working plane in office spaces when external shadings and light control systems are used. Simplified procedures are based on the split of the internal illuminance into two components due to direct and diffuse sun radiations, expressed by the Solar System Luminous Efficacies, calculated by the package Superlite. Comparisons are carried out on energetic basis by the hourly simulation program IENUS.