Improvement of fog harvesting materials for potable ...

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GRØN DYST 2014 Technical University of Denmark

Improvement of fog harvesting materials for potable water generation in arid regions
Paper
Author:S. Wunderlich (Munich School of Engineering and Chair of Ecoclimatology, Technische Universität München, Germany)
C. Schunk (Chair of Ecoclimatology, Technische Universität München, Germany)
P. Trautwein (Wasserstifung, Germany)
A. Menzel (Chair of Ecoclimatology, Technische Universität München, Germany)
Date: 2014-06-27     Track: Main     Session: 1

Half of the world’s population has limited access to drinking water and in 2025 2.3 billion people will have no constant fresh water supply. In coastal areas with scarce precipitation but a frequent occurrence of fog, fresh water can be harvested from the fog. This means that the wind carrying fog is pushed against vertically set-up fog meshes. The fibers of the fog mesh intercept the fog droplets, the droplets coagulate and with reaching a significant mass, they pour down the mesh to a collecting channel and from there to a storing tank. The “Raschel”-type meshes currently in use in several fog harvesting projects around the world show several disadvantages such as a low yield and inadequate mechanical stability. The main goal of this project therefore is to identify a fog harvesting material with improved characteristics, in this case, the highest yield. Five different materials which may be suitable for fog harvesting were examined using experiments and modeling techniques. They range from very simple meshes used e.g. for shading to three-dimensional structures that were specifically designed for this purpose. The experiments were conducted in a climate chamber where fog was sprayed on the different materials and the yield efficiency, along with the pour-off characteristics and rest water amount were measured. Additionally, the yield was calculated from hydrodynamic theory.