Fog collection improvement using harp structures formed from hairy yarns.

With the increasing global problem of water scarcity, unconventional methods for water supply, such as fog collection, are emerging as viable solutions in certain regions. This study proposes a harp structure composed of hairy yarns, inspired by the Cotula fallax plant, to improve the fog collection efficiency. The presence of hair fibers can greatly enhance fog collection efficiency. In the harp structure, where yarns are widely spaced, thin hair fibers improve aerodynamic efficiency by increasing the shade coefficient without substantially affecting the pressure drop coefficient of the fog collector. Due to their extreme fineness, these fibers can increase droplet capture efficiency by approximately 2.5 times compare to the optimized Raschel mesh and reduce onset time. Harp structures formed by hairy yarns, owing to the entanglement of their hair fibers, retain more water on their surfaces than the optimized Raschel mesh, and the clogging of these structures is influenced by the arrangement of the hair fibers. The parallel arrangement of the hair fibers forms channels that transfer the water via capillary action, which reducing clogging. When the hair fibers are oriented downward, smaller droplets separate directly from fibers, further decreasing onset time. These findings offer a deeper understanding of the role of hair fibers in the fog collection process and propose an effective strategy for designing an optimal fog collector. Specifically, this study experimentally evaluates the impact of the fineness, arrangement, orientation, and density of hair fibers on fog collection efficiency.