Passive Design Optimisation for Energy Performance of Naturally Cross-Ventilated Building Spaces in the Tropics

Abstract

The increased energy demand due to rapid economic growth and urbanisation has led to buildings becoming among the largest energy consumers, particularly in tropical climates. This study develops and validates an integrated simulation–prediction framework to identify optimal passive design strategies for a naturally cross-ventilated tropical building space. Seven passive design variables were investigated, including window-to-wall ratio, window orientation, glazing type, shading depth, wall thickness, external wall insulation and roof insulation thicknesses. From 16,384 possible design combinations, 4,915 alternatives were generated using Latin hypercube sampling. Dynamic thermal simulations were performed using the THERB for HAM. Sensitivity analysis was later conducted to understand the influential input variables. The findings of the study demonstrate that the window-to-wall ratio exhibits the most significant positive influence on cooling energy consumption, while roof insulation thickness shows the opposite trend. The optimal passive design configuration achieved an annual energy consumption of 32.86 kWh/m2/year, representing a 74.1% reduction compared to the baseline scenario of 127.11 kWh/m2/year. Therefore, it is recommended that building designers focus on these key input variables to achieve the most optimal passive design in terms of energy performance in the tropics.