Development and experimental assessment of an Evaporative cooling system with Wetting surfaces

The main source of energy consumption in evaporative coolers is the forced passage of air through wetted materials, which causes a significant pressure drop. In this study, to address this challenge and reduce the energy consumption of evaporative coolers, an innovative design with wetted surfaces was proposed, in which air flows parallel to the wetted surface instead of passing through it. To evaluate the proposed method, a laboratory prototype was constructed. Mathematical models predicting the effects of ambient temperature and airflow velocity on the performance indices of the cooler were developed using nonlinear multiple regression, based on experimental data obtained from field tests. Field experiments were conducted within an ambient temperature range of 15–32 °C and airflow velocities between 1–3 m/s. For validation of the obtained models, additional experiments under different conditions were performed, and the experimental results were compared with model predictions using statistical indices of coefficient of determination (R²) and root mean square error (RMSE). The results showed that both ambient temperature and airflow velocity affect performance indices through quadratic relationships. Cooling capacity improved with increasing ambient temperature up to about 25 °C, after which it declined. the highest cooling load within the experiments was around 1.7kW observed at the temperature of 23.5 °C with a velocity more than 3m/s. at such condition an effectiveness of 3.4 was achieved. Evaluation of the developed mathematical equations (R² > 0.98 and RMSE < 0.00532) revealed that the models accurately predicted the measured data.