Techno-Economic Optimization of Cellulose Corrugated Pads for Evaporative Cooling Systems Using the Net Saving Method

Nitipong Soponpongpipat, Supanut Taengcharoensuk, Pongsiri Jaruyanon

Abstract


This study develops a mathematical model to determine the optimum thickness of cellulose corrugated wetted pads in direct evaporative cooling systems by integrating heat transfer, airflow pressure drop, and total system cost. The model was validated against experimental data, achieving a minimum RMSE of 1.22 °C and a MAPE of 4.01%, confirming high predictive accuracy. Results show a U-shaped relationship between pad thickness and total cost, with an optimum point minimizing the combined expenses of pad material, fan, and pump energy. Sensitivity analysis identified inlet and outlet air temperatures as the most influential factors on optimum thickness. To avoid computationally intensive brute-force optimization, a third-degree polynomial correlation was formulated using saturation effectiveness as the input. The correlation predicted optimum thickness with MAPE below 4% and RMSE below 0.005 m for effectiveness values between 0.45–0.90. However, errors increased significantly beyond 0.90, with MAPE reaching 19.44%. Applicability analysis confirmed the correlation’s reliability across conditioned volumes of 15–1,500 m³, air change rates of 10–40 h⁻¹, and cost factors of 0.0090–0.0224, with errors under 12%. While the correlation provides a practical tool for preliminary design, comprehensive cost evaluation remains essential for final optimization.

Keywords


evaporative cooling pad; optimum pad thickness; polynomial correlation; saturation effectiveness; techno-economic analysis

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References


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DOI: https://doi.org/10.64289/iej.25.03A11.1208787