|Solex roof/fog harvesting system|
I have now completed my first fog harvesting system. It is approximately 200 sq. ft. of surface and captures about 5 litres of pure clean water on average per day when there is fog at night and in the morning. Materials cost about $2.00 per sq. ft. for construction. Right now I am not segregating this water, but rather, adding it to the existing rainwater storage tanks. Since the water is so clean, I might separate it at some point in the future.
The basic collection material is Solexx, a 3 mm thick twin wall UV protected polyethylene that comes in rolls 49.5 inches wide. The material is generally used instead of twin walled Lexan for a cheaper alternative for greenhouses.
In my case I have also installed a gutter on the lower edge to catch the water and transport it to the storage tanks. I originally bought the twin wall material to cover my pergola just so that I could protect certain cactus and succulent plants during the rainy winter months from too much rain. I was surprised how much fog was condensed onto the polyethylene and dripping onto the surface below, so I added the gutter.
I have also noted that the roof itself is also a fog catcher, but that water is automatically diverted to the same gutters and water storage tanks as the rainwater from the roof. It would be more difficult to segregate the two water sources and its purity might be more of a problem.