In cooling tower operation, increasing the inlet water temperature while holding air conditions constant will

• A. Increase heat transfer rate
• B. Decrease heat transfer rate
• C. Have no effect
• D. Cause condensation

Answer: (A)

The rate at which a cooling tower transfers heat is driven by the temperature difference between the hot water and the air. When you hold the air conditions constant and raise the inlet water temperature, that temperature difference increases, so more energy can be moved from the water into the air. This boosts the heat transfer rate, assuming the tower can handle the extra load and remains within its design limits. The higher water temperature also tends to increase evaporation, which helps remove heat, but the key point is the greater driving force for heat transfer. Condensation isn’t promoted simply by hotter inlet water under fixed air conditions.