What is "air well"

n. a shaft for ventilation [syn: air shaft]

An air well may be one of the following:

• Air well (condenser), a structure or device designed to promote the condensation of atmospheric moisture.
• Air well (ventilation), an architectural feature designed to promote ventilation.

117,000.|A radiative condenser in northwest India.]]

An air well or aerial well is a structure or device that collects water by promoting the condensation of moisture from air. 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: used in the early 20th century, but the approach failed.
• Low-mass, radiative collectors: Developed in the late 20th century onwards, proved to be much more successful.
• Active collectors: these collect water in the same way as a dehumidifier; although the designs work well, they require an energy source, making them uneconomical except in special circumstances. New, innovative designs seek to minimise the energy requirements of active condensers or make use of renewable energy resources.