CFD-Based Energy and Thermal Performance Evaluation of a Coconut Shell-Fired Downdraft Kiln for Sustainable Brick Production

Enhancing energy efficiency and reducing environmental impact in energy-intensive industries are essential for sustainable energy systems. This study numerically evaluates the energy and thermal performance of a coconut shell-fired downdraft brick kiln as a renewable alternative to fossil-fuel-based firing. A three-dimensional kiln model was analyzed using Computational Fluid Dynamics (CFD) to examine combustion, airflow, and heat transfer. Fuel properties from proximate and ultimate analyses yielded an adiabatic flame temperature of2242 K. Results indicate stable downdraft heat circulation, firing-zone temperatures above 1000 K, and a specific energy consumption of 2.7 MJ/kg while while the experimental batch SEC was 3.5 MJ/kg, demonstrating improved efficiency and reduced carbon intensity compared with conventional kilns.