Performance Optimization of a Terracotta Tube-Based Direct Evaporative Cooling System

Abstract

This study presents the design and testing of a lab-scale Terracotta Flat Tubular direct evaporative cooler constructed from locally sourced materials. The key components of the system include a galvanized steel box, hollow baked clay tubes with a flat geometry, an axial fan, and a low-power submersible water pump. Experiments were conducted to evaluate the effects of varying intake air velocity, and water temperature. The experiment was carried out between 2:30 PM and 5:00 PM where air temperature and humidity in the test room stabilize. The results demonstrated temperature reductions ranging from 5.9°C to 15.7°C, outlet relative humidity levels between 52% and 95%, and cooling effectiveness values from 0.41 to 1.11. The optimal performance of the cooler was achieved at air velocities of up to 1 m/s and water temperatures around 18°C, at which the Feasibility Index is less than 11, which is in the range of the recommended value. The prototype achieved a cooling capacity of 62 W, with a coefficient of performance ranging from 3.3 to 5.6. Recommendations for future work include scaling up the system and enhancing its compactness to improve performance, making it suitable for enhancing indoor air quality and thermal comfort in rural households, schools, and offices with limited power access, as well as assisting small-scale farmers in reducing postharvest losses of horticultural products.