Which dehumidification method involves dropping air temperature?

The dehumidification method that involves dropping air temperature is cooling. When air is cooled, it can reach its dew point, the temperature at which moisture condenses out of the air. This principle is based on the fact that warmer air can hold more moisture than cooler air. By lowering the temperature of the air, the ability of the air to retain moisture decreases, leading to condensation. This is commonly observed in air conditioning systems, where the cooling process not only reduces temperature but also results in the removal of humidity as water droplets form on the evaporator coils.

In contrast, heating would raise the air temperature, which would allow for increased moisture retention. Humidifying actively adds moisture to the air, which would increase humidity rather than decrease it. Pressurizing does not effectively contribute to dehumidification since it does not inherently change the temperature or moisture content of the air. Therefore, cooling stands out as the method that effectively lowers air temperature to facilitate dehumidification through condensation.