Assessment of evaporative cooling process across the mechanically driven cooling tower based on two-point boundary value problem using novel integral technique

Abstract

In the present study, a novel integral technique based on a two-point boundary value problem for the evaporative cooling process occurring across the mechanically driven counter flow cooling tower is structured and solved numerically. The developed technique is validated with the experimental data reported in the literature by choosing thermal load and vaporization rate as thermal performance evaluation parameters and observed the maximum deviation to be ± 13.5%. Moreover, the effect of inlet parameters on thermal load and vaporization rate is evaluated, and it is observed that water inlet temperature and air-specific humidity has a substantial influence on the performance of the cooling tower. Unique dimensionless parameters such as characteristic thermal mass of the packed column with tower height, heat difference ratio and moisture difference ratio along the height of the packed column, and number of heat-transfer units are introduced for assessing the performance as well as transfer characteristics of the cooling tower considering air as the cooling medium and water as the working fluid. The influence of various parameters such as Lewis number, number of heat and mass transfer units, fluid flow ratio, dimensionless thermal mass of the packed column with tower height, and moisture difference ratio on cooling tower efficiency is analyzed and observed that fluid flow ratio and moisture difference ratio have a significant impact on the thermal performance of the cooling tower. Further, for the given operating range, optimal values of number of heat transfer units, fluid flow ratio, and characteristic height of the cooling tower are predicted and found to be 0.87,0.35, and 0.8 m, respectively.