PARAMETRIC OF DAYLIGHT PERFORMANCE THROUGH FACADE ENVELOPE RATIO OF HIGH-RISE OFFICE BUILDING IN TROPICAL CLIMATES

In tropical climates, facade design plays a crucial role in balancing daylighting performance and thermal control to enhance energy efficiency and occupant comfort. This study investigated the parametric relationship between facade envelope ratio and daylighting performance in high-rise office buildings, focusing on optimising the Window-to-Wall Ratio (WWR) to meet visual comfort and energy-saving goals. Various facade configurations were evaluated using IESVE simulation software and validated against real-world data to determine their impacts on indoor illuminance levels and thermal transfer. The findings demonstrated that a facade envelope ratio of 80–90% with a setback depth of 1.5 m and a WWR of 70% yielded optimal daylight distribution, maintaining acceptable indoor illuminance levels between 230 lx and 300 lx. However, achieving this visual comfort created a significant thermal trade-off; this baseline configuration resulted in an Envelope Thermal Transfer Value (ETTV) of 102.88 W/m², far exceeding the 50 W/m² permissible limit outlined in Malaysia's MS1525:2019 standard. To resolve this without sacrificing the daylighting that occupants highly value, the study identifies that it is imperative to incorporate advanced facade systems, such as low-emissivity (Low-e) glazing, deliberate shading elements, and double-skin facades. Ultimately, this study proposes a performance-based design framework that reconciles daylighting goals with ETTV compliance, guiding architects to successfully enhance building energy performance and occupant well-being in tropical regions.