Natural Draft Cooling Tower
It is usually found in thermal power stations, coal-fired power stations, and nuclear power stations. It is very expensive to construct and they are only ever used where large cooling is required. It is used over a long period, for example,30 years. These towers are not to be put into service for 2 to 3 years because it doesn’t make economic sense.
- It has a slime middle body and it becomes gradually wider at the top and wider at the base.
- There is a drift coming out the top of the natural draft cooling draft. It looks like smoke but it’s evaporated cooling tower.
- The diameter of the base itself may be up to 100 meters.
- The height of the tower is approximately 200 meters.
- This natural draft cooling tower includes steel and reinforced concrete.
How it works:
At the base of the tower, there is a reservoir that is full of water. The water is drawn through the lower pipe to the power station. The water is then used to cool steam to condensate and it comes back at a slightly elevated temperature through the pipe and is discharged through the spray nozzles then spray onto the fill which is a large heat exchanger where the water is brought into contact with air over a large cross-sectional area. This means that there is a very large heat transfer between the water and the air. The water drops out of the fill and into the reservoir again and the air has been heated by the water. The air is going to rise because it is less dense than the ambient air. Due to the less dense, it becomes rises through the tower and discharges out at the top of the tower.
The ambient air is going to be drawn in through the base and the pipe, it’s going to be drawn upward and pass again through the fill to replace the warm air which has been drifting out. This process is continuous and more air is expelled through the top of the cooling tower.