Optimisation of daylight admission based on modifications of light shelf design parameters

This study was conducted to optimise daylight admission as ambient lighting in an open-plan examination room of a dental hospital in Bandung, Indonesia. Parametric design was conducted for new light shelves, to be placed on the east and west facades of the building. Optimisation was performed using genetic algorithm, taking into account the external and internal widths, external tilt angles, and specularity of the light shelves, for two scenarios: keeping and removing the existing overhangs on both facades. The optimisation objectives were to maximise the spatial daylight autonomy at the perimeter area (sDA(300/50%(p))) and minimise the annual sunlight exposure (ASE(1000,250)) on the occupied floor area of the examination room. Different optimised values were obtained for the east and west facades. In the first scenario, the resulting objective function yields an increase of 4.9% compared to existing condition, whereas the increase is 16.7% in the second scenario. Both metrics in the second scenario have satisfied the criterion. Uncertainty in the first scenario is found smaller than that in the second scenario, due to the removal of overhangs that bring more daylight in the latter.