How to choose a closed cooling tower

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How to choose a closed cooling tower

Apr 19, 2025

When many customers choose a closed cooling tower for the first time, they often think that the larger the closed cooling tower, the better. They make a margin when making decisions, which leads to increased costs.

The decisive factor that determines the size of a closed cooling tower is heat. The heat calculation formula is: Q=cmΔT, that is, Q absorption (release) = cm(T initial - T end) where c is specific heat, m is mass, and Q is energy heat. When absorbing heat, it is Q=cmΔT rise (the actual increase in temperature minus the initial temperature of the object), and when releasing heat, it is Q=cmΔT drop (the actual initial temperature minus the temperature after the drop). Or Q=cmΔT=cm(T end - T initial), when Q>0, it is absorbing heat, and when Q<0, it is releasing heat. Q absorption = cm (t-to) Q release = cm (to-t): c represents specific heat capacity. m represents the mass of the object, to represents the initial temperature of the object, and t represents the final temperature of the object, (△t: the temperature of the object change, that is, t-t0). The selection requirements for a certain project of Jiangsu Huatal are as follows: cooling water design water volume: 250m³/h, circulating cooling return water temperature: t1=55℃, circulating cooling feed water temperature: t2=42℃, temperature difference: △t=13℃, wet bulb temperature reference: 28.6℃, the selection process is as follows:

1.Determine the water temperature difference drop 55℃-42℃=13℃

2.Determine the approximation (temperature difference between outlet water temperature and wet bulb temperature) 42℃-29℃=13℃;

3.Heat rejection coefficient: From the table, it can be seen that the approximation is 13℃ when the wet bulb is 29℃, and the corresponding heat rejection coefficient = 0.24

4.Calculate the heat load: water volume (L/s)*temperature drop (℃)*4.186=3754.8kw

5.Corrected load: load*heat rejection coefficient=901kw. According to the theorem of conservation of heat, just find the closed cooling tower with the corresponding heat.

Secondly, the tower type and volume of the closed cooling tower also have an impact. The popular closed cooling towers are divided into counterflow closed cooling towers, crossflow closed cooling towers and compound flow closed cooling towers. Under the same heat working conditions, the volume of crossflow and compound flow is much larger than that of counterflow due to the design of the maintenance channel.

The process level also determines the size of the closed cooling tower at different stages. The closed cooling tower is a comprehensive subject summary, covering aerodynamics, heat transfer, structural science, materials science and other fields. Different coils have different heat transfer coefficients, and the size of their area can affect the size of the closed cooling tower. The development of fan technology and the diameter of its blades directly affect the width of the closed cooling tower. Therefore, the size of the closed cooling tower is not a random combination, but the result of calculation and experimental testing.

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