To explore the thermal performance and optimization direction of a large natural draft cooling tower

the thermal performance of a large natural draft cooling tower with a watering area of 12 000 m2 was tested for a 1 000 MW coal-fired unit. The gas-water ratio and cooling number were used to fit the results

and thermal performance equation and correction coefficient of the cooling test tower were obtained. The distribution of the measured wind temperature in the tower was given. The water temperature of the tower was calculated using different resistance coefficient formulas. The results showed that the correction coefficient of industrial towers with equal heights of packing and those with unequal packings was 1.047–1.081. The root mean square error of the air temperature in the industrial towers with unequal heights of packings was 0.56–0.67 ℃

which was less than the corresponding cooling tower with equal heights of packing. Thus

the cooling performance of the cooling tower could be enhanced by the unequal arrangement of the packing. The water temperature of the tower could be quickly calculated by using the empirical formula of resistance under the condition that the amount of water entering the tower was large

which provides a reference for the design and modification of large natural draft cooling towers.