Investigation of heterogeneity of cooling temperature in evaporative cooling towers

Evaporative cooling towers are important devices for cooling circulating water in thermal and nuclear power plants. The main performance indicators of condensers and steam turbines depend on their efficiency of operation. For example, when the final water temperature rises by 1 degree at the outlet of a cooling tower, there is a 0.5 % decrease in condenser vacuum and a 0.4 % decrease in steam turbine capacity. Evaporative cooling towers are notable for their large size, another important task of which is to cool large volumes of circulating water typically from 8 500 to 30 000 TPH.

However, large units are usually characterized by a heterogeneous process. In this paper, we consider the analysis of temperature field heterogeneity in evaporative cooling towers of various types. An experimental study of cooling heterogeneity in several cooling towers has been conducted. Histograms of cooled water temperature distribution were plotted and degrees of heterogeneity were established. It was found that each evaporative cooling tower has an individual degree of water-cooling heterogeneity under practically equal operating and environmental conditions. The effect of the degree of water-cooling heterogeneity on the evaporative capacity of cooling towers was analyzed. The analysis of the causes of heterogeneity in the process of water cooling was carried out. It has been revealed that temperature heterogeneities occur due to the cooling tower design features, its location on the ground, and the distribution of water and air flows inside the device. Measures to reduce temperature heterogeneity of cooling in evaporative cooling towers are proposed.