Circulating water
Thread Content
I’m wondering, why is this the case in an open-type cooling tower system when the operating conditions remain unchanged? The temperature difference in summer is 6 degrees, with a circulation volume of 12,000 cubic hours; in winter it is 7.8 degrees, with a circulation volume of 11,500 cubic hours. Based on these figures, the amount of water that needs to be added to the system in winter is much greater than in summer. However, the actual situation on site is the opposite. Thank you!
Water replenishment volume = water discharged + water evaporated + splash loss, among which water evaporated and water discharged have the greatest impact. You can check your own data regarding the amount of water discharged. The amount of water that evaporates is calculated as temperature difference × volume of water in circulation × evaporation coefficient. Therefore, in winter, an increase in the temperature difference alone does not necessarily lead to a change in the amount of water that needs to be added; there is also another important parameter, namely the evaporation coefficient, which typically ranges from 0.8 to 0.9. This value tends to be higher in summer ； The evaporation coefficient is primarily determined by the cooling method of the circulating water, namely latent heat and sensible heat; if you are interested, you can look up relevant information ；
There’s an issue with your calculation method; under normal operating conditions, whether theoretically or in practice, the amount of water that needs to be added in summer is definitely greater than in winter
How did you calculate it? There’s something wrong with the calculation method!
The amount of condensation varies, which is roughly equivalent to the reflux rate in distillation； Considering the increased temperature difference, the condensation return flow increases while evaporation (production volume) decreases ；
The evaporation rate varies significantly between winter and summer; the evaporation coefficient is related to temperature, and based on this, the amount of water that needs to be added is calculated (more in summer than in winter)
Because the cooling tower does not run its fans in winter. It has no effect of extracting water vapor. It’s not just about seeing who takes away more heat through evaporation. A dynamic equilibrium vapor pressure is formed between water and air. It will effectively prevent the loss of moisture. Reduce the amount of water added.
As a layperson would say, a cooling tower works by using evaporation to remove heat, through heat exchange with air, and to some extent through radiation; in any case, there is less heat generation in winter!
Small units are different from large units; for small units, a value of 40-60 times the steam inlet volume of the turbine is generally used； For large units, the values are generally taken as,,,,,,,,,,,,,,,,,