MAPPING DAYLIGHTING ZONES IN NIGERIA USING EMPIRICAL DATA AND CLIMATE MODELLING

Abstract

This study investigates the relationship between the widely used Koppen-Trewatha-Horn (KTH) climate classification system of Nigeria and daylighting performance. It assesses the suitability of existing climate zones for assessing daylighting effectiveness through Climate-Based Daylight Modelling (CBDM) in test classrooms at 24 locations across the country. Data analysis using both supervised (Chi-square goodness-of-fit) and unsupervised (hierarchical clustering) statistical tests reveals a marked difference between the traditional climate zones and the empirically derived daylighting zones. The research provides new, evidence-based daytime zone maps for Nigeria using daylighting metrics such as Daylight Autonomy (DA), Useful Daylight Illuminance (UDI), and Daylight Uniformity Index (DAUI). The results indicate that the best-fit daylighting zones do not align with the conventional climate zone limits, suggesting that expert daylighting classification schemes should be employed in architectural design practices. The research forms the basis for the design of Nigerian and other tropical region-specific daylighting design guidelines.