Experimental Performance Evaluation of Clay-Based Cooling Pads with Optimized Geometry for Direct Evaporative Cooling Systems

Evaporative cooling is an energy-efficient and eco-friendly cooling method; however, conventional cellulose or plastic pads are costly, non-renewable, and require frequent replacement. This research explores the suitability of using burnt clay as a green, low-cost, and readily available alternative cooling pad material. Two clay-based cooling pad geometries, a cone-shaped and a cylindrical design, were fabricated from pure clay and experimentally evaluated in a laboratory-scale direct evaporative cooling system. The cooling capacity was evaluated in terms of inlet and outlet air temperatures at the defined operational conditions with continuous water flow, assisted by a fan forced‐airflow. A commercially available cellulose honeycomb pad was tested under identical conditions, and the results showed that clay-based cooling pads achieved comparable efficiency. The cone-shaped clay pad provided a cooling efficiency of about 65%, the cylindrical pad a value of about 62%, versus the 68% value obtained for the cellulose pad. The variation in the outlet air temperature of clay-based pads to the cellulose pad was lower than 1 °C at all tested readings. Water retention and durability tests confirmed that the clay pads maintained sufficient moisture for effective evaporation after repeated wet–dry cycles, with the conical design showing superior overall performance.