A Termite-Inspired, Seasonal Approach to Window-to-Wall Ratio Design for Thermal Comfort in Office Buildings in Nigeria's Temperate Dry Region
Abstract
It is common knowledge that buildings in tropical countries are often affected by thermal discomfort. As a result, different window sizes and positioning strategies have been explored to mitigate this issue. Consequently, many studies have been conducted to determine the optimal window-to-wall ratio (WWR), a critical factor influencing thermal comfort in tropical regions. For example, research has shown that buildings with a WWR above 20% do not provide comfortable temperatures in tropical climates. The International Energy Conservation Code (2012 IECC) recommends a different value of 30%, while a study conducted in Singapore’s temperate dry climate found the optimal WWR to be 24%. However, none of these studies achieved consistent thermal comfort indoors, primarily because they did not account for seasonal variations, instead applying their findings uniformly throughout the year. Recent studies suggest that the optimal WWR varies by season. For instance, a 25% WWR was found to be optimal during the dry season, while 35% was ideal for the wet season. Interestingly, termite mounds maintain a stable internal climate despite fluctuating external conditions, making them an excellent model for improving thermal comfort in buildings. Research has revealed that termite mounds employ adaptive WWR modulation, using 30% WWR in the wet season and 25% in the dry season for thermoregulation. This study investigates the impact of seasonal WWR adjustments (10%, 15%, 20%, 30%) on thermal comfort in Nigerian office buildings through simulation, addressing the gap in climate-responsive design. It compares the WWR strategies of termite mounds and human buildings by evaluating WWR performance during hot and cold seasons. A prototype building was simulated using SketchUp, Revit, and DesignBuilder on hypothetical sites in Abuja, free from surrounding structures and trees. The generated data were analyzed using MANOVA, bar charts, column charts, graphs, and tables, with a significance threshold of 0.05. The findings revealed that the optimum WWR in office buildings in temperate dry climate of Nigeria are 15% WWR in hot season and 20% in cold season, which inversely mirror termite mound strategies of 30% in hot season and 25% in cold season. While human buildings prioritize minimizing heat gain, termite mounds utilize controlled ventilation for passive cooling.