A computer model for predicting the daylight performance of complex parallel shading systems

In tropical areas where the exclusion of solar heat from buildings is a paramount consideration, shading systems consisting of adjustable parallel multiple slats have evolved which exclude direct solar radiation whilst permitting some daylight penetration. The modelling of daylight illuminance from these systems is not easy using conventional graphical or computational quantitative techniques. This paper sets out a computer-based model for the analysis of the general case of parallel shading systems. The model is illustrated by reference to the Rowshan shading system used in the Hedjazi architecture of Saudi Arabia.