Cooling towers that pass air over water are limited in capacity by which temperature?

The capacity of cooling towers that pass air over water is fundamentally influenced by the outside air wet bulb temperature. The wet bulb temperature reflects the lowest temperature to which air can be cooled by the evaporation of water, which is critical for the cooling process in these towers.

When air moves over the water in a cooling tower, evaporation occurs, which effectively cools the water while simultaneously cooling the air. The efficiency of this cooling process is determined by the moisture content of the air, which is represented by the wet bulb temperature. Therefore, as the outside air wet bulb temperature increases, the cooling capacity of the tower diminishes since the air cannot absorb as much heat from the water, limiting the cooling effect.

In contrast, other temperature measures such as dry bulb temperatures do not account for the moisture content in the air and thus are less relevant in assessing the cooling capacity in this context. Understanding the role of wet bulb temperature is crucial in optimizing the performance of cooling towers.