What does cooling tower drift loss refer to?

What does cooling tower drift loss refer to?

• A. Evaporation losses within the tower
• B. Condensation on fans
• C. Water droplets carried away with exhaust air
• D. Heat transfer to ambient air

Answer: (C)

Drift loss is the portion of cooling-tower water that leaves with the exhaust air as tiny droplets. As water is sprayed into the tower and cooled by air flow, some droplets become entrained in the upward air stream and are carried out of the tower rather than returning to the basin. This liquid water loss reduces the circulating water available for cooling and increases makeup water requirements; drift eliminators are used to minimize it. This is different from evaporation losses, which are water that turns into vapor and exits as humidity in the exhaust—not visible droplets. It’s also not moisture condensing on fans or structures, or the general heat transfer process itself, which describes how the tower cools rather than how much water is being lost.

Drift loss is the portion of cooling-tower water that leaves with the exhaust air as tiny droplets. As water is sprayed into the tower and cooled by air flow, some droplets become entrained in the upward air stream and are carried out of the tower rather than returning to the basin. This liquid water loss reduces the circulating water available for cooling and increases makeup water requirements; drift eliminators are used to minimize it.

This is different from evaporation losses, which are water that turns into vapor and exits as humidity in the exhaust—not visible droplets. It’s also not moisture condensing on fans or structures, or the general heat transfer process itself, which describes how the tower cools rather than how much water is being lost.