Fog collection
As the exposed surface cools by radiating its heat to the sky, atmospheric moisture condenses at a rate greater than that of which it can evaporate, resulting in the formation of water droplets.
This requires no external energy and is facilitated naturally through temperature fluctuation, making it attractive for deployment in less developed areas.
[3] The organized collection of dew or condensation through natural or assisted processes is an ancient practice, from the small-scale drinking of pools of condensation collected in plant stems (still practiced today by survivalists), to large-scale natural irrigation without rain falling, such as in the Atacama and Namib deserts.
The first man-made fog collectors stretch back as far as the Inca Empire, where buckets were placed under trees to take advantage of condensation.
One of the first recorded projects of fog collection was in 1969 in South Africa as a water source for an air force base.
The next large study was performed by the National Catholic University of Chile and the International Development Research Centre in Canada in 1987.
Redwood forests are able to survive on limited rainfall due to the addition of condensation on needles which drip into the trees' root systems.
The frame supports the mesh netting and can be made from a wide array of materials from stainless steel poles to bamboo.
Fog collection is considered low maintenance because it requires no exterior energy and only an occasional brushing of the nets to keep them clean.
[6] In the mid-1980s, the Meteorological Service of Canada (MSC) began constructing and deploying large fog collecting devices on Mont Sutton in Quebec.
With funding from the International Development Research Centre (IDRC), the MSC collaborated with the Chileans to begin testing different designs of collection facilities on El Tofo Mountain in northern Chile.
Once vegetation became established, it should have begun collecting fog for itself, like the many cloud forests in South America, in order to flourish as a self-sustaining system.
Though this was not in the scope of CONAF, which pulled out at this point, it was agreed to expand the collection facility to 94 nylon mesh collectors with a reserve tank and piping in order to supply the 300 inhabitants of Chungungo with water.
[citation needed] Conversely, the MSC states in its article that the facility was still fully functional in 2003, but provides no details behind this statement.
Researchers conducted fog harvesting in Alto Hospicio, situated in the Atacama Desert, by the coast, is one of the driest places on Earth.
The average annual rainfall in the region is less than 0.19 inches (5 mm); the city faces significant social challenges, with high levels of poverty and reliance on water delivered by truck.
[9] In March 2015 Dar Si Hmad (DSH), a Moroccan NGO, built a large fog-collection and distribution system in the Anti-Atlas Mountains.
[12] According to MIT researchers, the fog collection methods implemented by DSH have "improved the fog-collecting efficiency by about five hundred per cent.
Shortly after the initial success of the project, researchers from the participating organizations formed the nonprofit organization FogQuest, which has set up operational facilities in Yemen and central Chile, while still others are under evaluation in Guatemala, Haiti, and Nepal, this time with much more emphasis on the continuing involvement of the communities in the hopes that the projects will last well into the future.
