A desert cooler cools better on a hot, dry day because the lower humidity allows for faster water evaporation, a key component of the cooling process. The higher the temperature and the lower the humidity, the more efficiently water evaporates, taking heat from the surrounding air and producing a cooling effect.
Here’s a more detailed explanation:
Evaporative Cooling:
Desert coolers work by drawing in hot, dry air and passing it over a wet pad or wick where water evaporates.
Humidity’s Role:
Humidity refers to the amount of water vapor in the air. On a hot, dry day, the air has a low moisture content, meaning it can hold more water vapor.
Faster Evaporation:
When dry air comes into contact with water, it absorbs the water vapor more quickly than it would in humid air.
Increased Cooling:
As water evaporates, it absorbs heat from its surroundings, primarily the air. This heat absorption cools the air that flows over the wet pad.
The Cycle Repeats:
The fan then circulates the now cooler, moister air back into the room, creating a cooling effect.