Modeling Heat and Mass Transfer in a Wet Terracotta Tube Channel for Evaporative Cooling Application: Influence of Geometrical Parameters

Abstract

This study investigates the influence of design parameters on the performance of a terracotta tube-type evaporative cooling system. A mathematical model was developed based on double film theory and energy and mass conservation equations of the humid air and the wet tube wall in a one-dimensional geometry by applying correlations for heat and mass transfer coefficients and air psychometric properties. A system of non-linear differential equations was established and analytically integrated to obtain the relationship between the operating and the geometrical parameters of the system. Various geometrical parameters were simulated to assess their effects on outlet air temperature, cooling capacity, and wet-bulb effectiveness. The results indicate that increasing the tube equivalent diameter results in higher outlet temperatures and cooling capacity but decreases wet-bulb effectiveness. Conversely, an increased flatness ratio significantly enhances cooling performance and wet-bulb effectiveness due to a larger surface area for heat exchange. Additionally, longer tubes correlate with lower outlet temperatures and higher cooling capacity, indicating improved cooling performance. These findings emphasize the importance of selecting appropriate tube dimensions to optimize cooling efficiency in evaporative cooling systems. By balancing hydraulic diameter, flatness ratio, and tube length, engineers can design compact and effective cooling solutions suitable for various applications, ultimately contributing to energy-efficient and sustainable cooling technologies. The modeling approach developed in this study can also be applied to address challenges in geothermal energy extraction, drying of porous solids, food processing and storage, building thermal insulation, nuclear reactor cooling, and seawater desalination.