Field test study on thermal and ventilation performance for natural draft wet cooling tower after structural improvement

Abstract In order to improve the operating performance of the natural draft wet cooling towers (NDWCTs), some structural improvement measures, including adding air-deflectors, using non-uniform fillings, and adding air-ducts, were taken in one large-scale NDWCT in China. The effects of structural improvement on the ventilation and thermal performance were researched based on the field test method. Field test results showed that, in the crosswind velocity range of 1.15–3.2 m/s (test condition), the thermal and ventilation performance decrease gradually with the rising of crosswind velocity, but the structural improvement weakens the adverse influence of crosswind. Compared with before structural improvement, the intake air uniformity coefficient, the ratio factor of ventilation rate, the temperature uniformity coefficient, and the ratio factor of Merkel number increase by about 36.6%, 15.5%, 5.5%, and, 14.5%, respectively. It manifested that the structural improvement for the NDWCT can improve the thermal and ventilation performance to a great extent.