Fog collection

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Fog collection is the harvesting of water from fog using large pieces of vertical mesh netting to induce the fog-droplets to flow down towards a trough below. The setup is known as a fog fence, fog collector or fog net. Through condensation, atmospheric water vapour from the air condenses on cold surfaces into droplets of liquid water known as dew. The phenomenon is most observable on thin, flat, exposed objects including plant leaves and blades of grass. 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.^[1][2]

Water condenses onto the array of parallel wires and collects at the bottom of the net. This requires no external energy and is facilitated naturally through temperature fluctuation, making it attractive for deployment in less developed areas. The term 'fog fence' comes from its long rectangular shape resembling a fence, but fog collectors are not confined just to this structural style.^[3] The efficiency of the fog collector is based on the net material, the size of the holes and filament, and chemical coating. Fog collectors can harvest from 2% up to 10% of the moisture in the air, depending on their efficiency.^[4] An ideal location is a high altitude arid area near cold offshore currents, where fog is common, and therefore, the fog collector can produce the highest yield.^[3]