International Journal of Science, Engineering and TechnologyAuthors: Ar. Suman Sharma, Shavni jain
Abstract: This study compares different terracotta façade geometries to find which shape gives the best passive evaporative cooling in hot–dry climates. Hot–dry regions usually have very high temperatures (above 40°C) and very low humidity (below 25%), which increases the need for cooling in buildings. Using mechanical air-conditioning consumes large amounts of energy, so passive cooling methods are important for sustainable architecture. Evaporative cooling works when water evaporates from a surface and absorbs heat from the surrounding air, reducing temperature. Terracotta is a suitable material for this purpose because it is porous (20–30% porosity), meaning it can absorb water through capillary action and slowly release moisture for continuous evaporation. It also has good thermal mass, which helps in reducing temperature fluctuations between day and night. The research studies different geometric shapes of terracotta façade modules such as square, hexagonal, triangular, cylindrical, grooved, perforated, and pleated forms. Geometry plays an important role in cooling performance because it affects surface area, airflow movement, shading, and water retention. Shapes with higher surface area and deeper recesses allow more water to stay on the surface and increase evaporation, resulting in better cooling. The study compares the performance of these shapes using parameters such as Surface Area to Volume ratio (SA/V), ventilation efficiency (ACH), shading coefficient (SC), and water retention time. Findings show that simple planar shapes like square tiles provide basic cooling, while complex shapes perform better. Cylindrical forms improve airflow and provide consistent cooling. Pleated or capillary geometries give the best results because they create larger surface area, better shading, and improved water distribution. Results from case studies show that pleated terracotta façades can reduce surface temperature by about 10–13°C, while cylindrical systems provide 9–11°C cooling. Perforated and hexagonal geometries show moderate performance. Based on comparative analysis, pleated or capillary geometries achieve the highest Evaporative Cooling Index (ECI = 10.0) and are considered the most suitable option for passive cooling in hot–dry climates. The study concludes that terracotta façades with optimized geometry can significantly reduce heat gain and cooling energy demand in buildings. Pleated or capillary designs are recommended for new façade systems, while cylindrical and grooved forms are suitable alternatives depending on project requirements. This research helps architects select façade geometries based on performance rather than only aesthetics, contributing to climate-responsive and sustainable building design.
