Consider the following statements in respect of natural-draft cooling towers:

1) Theoretically the water can be cooled to even below the dry-bulb temperature of the induced air flow.

2) Nature-draft cooling towers are 100 m or more in height.

3) The inner and outer surfaces are surfaces of revolution of a segment of a hyperbola about the vertical axis-affording improved strength rather than any thermodynamic augmentation.

Which of the above statements are correct?