Cooling Towers are used to cool the water that is used to re-condense the steam that is used to generate electricity. Typically over 100m tall and completely hollow above the first 15m, the concrete shell of the tower thins out to only six inches thick at the top. Weighing in excess of 3000 tons, the strength of the tower lies in its parabolic shape.
It is essential to detect any distortions in the shape of the tower or weaknesses in the concrete, as these may cause the tower to collapse.
A Cooling Tower near Bombay, India
The power source used to generate the steam may be nuclear, coal or gas. The following diagram shows the important role the Cooling Tower has in the formation of Energy.
Cooling water which has become hot cooling the turbine steam is pumped to the tower where it is sprayed out from a large pipe circulating the base. Cold air enters the base of the tower and acting like a chimney carries the steam out of the top of the tower. The hot water itself cools in the air and falls into a large pond situated beneath the tower. This water cools even more on its journey back to the condenser.
Visual Inspections may be carried out by looking at the Cooling Tower from the ground by use of a theodolite telescope. The position of any concrete cracks or exposed re-enforcing steel can be accurately surveyed and monitored at a future date to detect any deterioration.
The as-built shape of the Tower can also be surveyed using theodolites from the ground, and a comparison made to the design shape of the Tower. By comparing the radius of the tower at any given height, bulges and depressions can be plotted onto paper and shown in a contour drawing.