Generally referred to as an atmospheric water generator, there are a number of ways that a machine can extract water from the air. The most common methods are cooling the air below its dew point or exposing the air to desiccants, although pressurizing the air can also be used to extract water.
In a condensing atmospheric water generator, the air passes over a heat exchanger or cool coil. When the warmer air passes over the cooler coil, it causes the water vapor in the air to condense into liquid. The water is then removed from the air through a process known as dehumidification. The water then passes into a holding tank, which usually features a filtration and purification system to ensure the water is clean and free from any viruses and bacteria that may have been present in the ambient air. In this type of atmospheric water generator, the rate of water production depends on multiple factors, including humidity, ambient air temperature, the volume of air passing over the coil and the machine's ability to keep the coil sufficiently cooled.
In the desiccation method, a liquid desiccant such as lithium bromide or lithium chloride is used to pull the water from air via a hygroscopic process. Dry, solid desiccants such as silica gel or zeolite may also be used in the same manner when combined with pressurizing the air.