Formulation of climate-based daylighting design prediction model for high performance tropical school classrooms

Daylighting is beneficial in buildings, including school classrooms, in which daylight can significantly affect the occupants’ performance. Also, daylight varies across different climates, including within the tropical region. Climate-based daylight modelling is recommended to accurately predict annual daylight performance in building spaces; however, it is often too complicated in practice. It is intended to have certain climate variables that can act as predictors for annual daylight performance in tropical school classrooms, where openings are typically installed on opposing façades. This study thus aims to propose a climate-based daylighting design prediction model for tropical school classrooms with symmetrical and asymmetrical opening typologies. The model considers horizontal shading depth and its height, and window-to-wall ratio, in relation with the climate variables. To achieve the objective, two classrooms with asymmetrical and symmetrical bilateral openings are modelled and optimized for 117 site locations in Indonesia. The spatial average UDI250-750lx is proposed as the reference metric that can ensure satisfaction of all daylight criteria. The annual global horizontal radiation (aGHR) is proposed as the predictor in the model, with prediction errors below 5 %. Simple equations have been derived to predict spatial average UDI250-750lx in tropical classrooms as a function of aGHR.