Industrial Processes usually produces a lot of heat. Air-conditioning also removes heat from the indoor areas through heat exchangers.
Where does all the heat go?
Cooling towers make use of air currents to cool warm water. However, a basic rule has to be made when you want to extract heat from any object, including water. Heat has to be taken from a higher temperature source to a lower temperature medium.
If the air is already warm, it will not be able to cool down the warm water. The temperature difference is very important.
Another important point in cooling tower efficiency is how much the water is exposed to the air. If the water is allowed to trickle down, and their contact surface with the air is made large, more heat exchange takes place.
Plastic diffusers designed with wavy patterns are inserted at cooling towers to increase the contact surfaces of the water when it meets with the cooling air stream.
There are several shapes of cooling towers, but they operate on the same principle.
There are basically 2 types airflow patterns in cooling towers:
The cross-flow type of cooling tower makes use of air flowing at right angles to the water dropping down. The fans are positioned so that the air stream flows through the cooling tower from the sides. Water is distributed at the top, and is allowed to drip down to meet with the air.
The characteristic shape of these cooling towers is usually rectangular shape. Depending on the design, there may be several small fans installed at the top of the cooling tower. However, the fan(s) may also be located at the sides of the cooling tower and the air may be ducted.
The counter-flow type of cooling tower makes use of air flowing in the opposite direction and against the flow of the water. In one design, water flows out through rotating spreader arms to distribute the water and let it drop through the plastic diffusers evenly.
In this design, the shape of the cooling tower is a bottle shape. It is fitted with one single large fan to suck the air to create the airflow. The diameter of the area where the heat exchange takes place is made larger so that more contact surfaces is exposed. The fan is heavy and huge. Its speed is usually made lower than that of the motor by the use of reduction gears.
There may be a few designs. Some use fans located at the bottom, some have fans at the top, some have large fans, some make use of several small fans. oil mist collector