Wikipedia Entry : Air well (condenser)

An air well or aerial well is a structure or device that collects water by promoting the condensation of moisture from air.[2]Designs for air wells are many and varied, but the simplest designs are completely passive, require no external energy source and have few, if any, moving parts.

Three principal designs are used for air wells, designated as high mass, radiative, and active:

• High-mass air wells were used in the early 20th century, but the approach failed.