Clogged air louvers under an induced draft cooling tower will produce which result?

• A. Higher return water temperature
• B. Lower return water temperature
• C. No change
• D. Higher ambient humidity

Answer: (A)

Induced-draft cooling towers rely on ample air flow across the water-filled fill to transfer heat from the water to the air, with evaporation helping remove heat. If the air louvers are clogged, air movement through the tower is restricted, so less heat is carried away and evaporation decreases. That means the water loses less heat inside the tower and returns to the system at a higher temperature. The ambient humidity isn’t the primary change caused by the clog, so the noticeable effect here is the warmer return water.