The evaporation cooling towers exploit a simple and natural physical principle, the forced evaporation of a minimum amount of water reduces the temperature of the main water body. Therefore, cooling towers represent the cooling system most used in civil and industrial applications today.
The temperature of the wet bulb in the installation area is the minimum output temperature that can theoretically be obtained from a cooling tower. Also, unless the air is saturated, this value is always lower than the temperature of the dry bulb.
A cooling tower of adequate size achieves practically cooling the circulating water to a temperature of 2-3 ° C above the temperature of the wet bulb. This is due to the effects of the performance factors related to air saturation.
On this basis, many designers and equipment manufacturers plan to use the water from the cooling tower while dimensioning the cooling circuits and heat exchangers. In this way they guarantee an optimum efficiency of the plant from the first stage of design.
On the other hand, the closed circuit cooling towers, instead of the filling for temperature transfer, we will find a coil. The fluid to be cooled flows inside the coil. In addition, an annex circuit equipped with a pump is responsible for collecting the water from the pool, to take it to the top of the tower where it again precipitates on the coil cooling it by humidification.
In the closed cooling towers the fluid to be cooled does not come into contact with the air so any risk of contamination is avoided.