{
    "title": "Fog-Collector",
    "inventor_name": "Sheerang Chhatre",
    "publication_year": 2011,
    "device_name": "Fog-Collector",
    "goal": "Collect clean drinking water from atmospheric fog for use in arid and water-scarce regions.",
    "problem_addressed": "Lack of safe drinking water for hundreds of millions of people living in arid environments and remote villages.",
    "concept_summary": "A permeable mesh structure coated with alternating hydrophobic and hydrophilic surfaces, inspired by the Namib beetle, that attracts fog droplets, coalesces them, and allows gravity-driven runoff into collection containers.",
    "detailed_description": "The device consists of a fence-like mesh panel whose strands are sized and spaced to maximize droplet capture. The mesh is coated with a low-contact-angle-hysteresis hydrophobic material on the outer surface and hydrophilic regions that promote droplet nucleation. Fog droplets impinge on the mesh, adhere to the hydrophilic bumps, grow, and then roll off the hydrophobic troughs into receptacles below. Laboratory tests aim to optimise strand radius, spacing, and coating chemistry to increase capture rates. Field deployments (e.g., FogQuest installations in Guatemala) have demonstrated ~1 L m^-^2 day^-^1 capture, while a proprietary hydrophobic coating from NBD Nano claims up to a 5x increase.",
    "category": "Mechanical Engineering",
    "principles": [
        "Wettability contrast (hydrophobic vs hydrophilic surfaces)",
        "Surface tension driven droplet coalescence",
        "Gravity-driven runoff",
        "Capillary action on micro-textured bumps",
        "Mesh permeability to allow airflow"
    ],
    "scientific_domains": [
        "Chemical Engineering",
        "Mechanical Engineering",
        "Materials Science",
        "Environmental Engineering"
    ],
    "mechanisms_of_action": [
        "Hydrophobic coating reduces droplet adhesion on troughs",
        "Hydrophilic bumps promote droplet nucleation and growth",
        "Gravity causes droplets to slide into collection containers",
        "Mesh geometry creates turbulent airflow that enhances droplet capture"
    ],
    "materials": [
        "Polymer or metal mesh strands",
        "Hydrophobic coating (e.g., wax, fluoropolymer)",
        "Hydrophilic coating (e.g., silica, functionalized polymers)",
        "Support frame (e.g., aluminum, PVC)"
    ],
    "energy_sources": [],
    "inputs": [
        "Atmospheric fog (water droplets)",
        "Wind (airflow)",
        "  "
    ],
    "outputs": [
        "Collected liquid water"
    ],
    "claimed_performance": "Field tests report ~1 L of water per square meter of mesh per day; NBD Nano coating claims up to a 5x increase in capture rate and 150-200% improvement in condensation heat transfer.",
    "experimental_evidence": "Fog-harvesting nets installed in Guatemala supplied water for ~150 people; laboratory tests on mesh spacing and coating chemistry are ongoing; NBD Nano coating demonstrated 500 h durability with little performance loss and 5x fog-capture improvement in recent trials.",
    "replication_status": "Multiple independent deployments (FogQuest in Guatemala, pilot sites funded by USDA for NBD Nano) indicate the technology has been replicated in field conditions.",
    "keywords": [
        "fog harvesting",
        "hydrophobic coating",
        "hydrophilic surface",
        "mesh collector",
        "desert beetle",
        "water scarcity",
        "passive water collection"
    ],
    "related_technologies": [
        "Fog nets",
        "Condensation heat-transfer coatings",
        "Mist elimination in turbines",
        "Dropwise condensation surfaces"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.7,
    "fringe_score": 0.1,
    "evidence_strength": 0.6,
    "risk_score": 0.1,
    "trl_estimate": 5,
    "source_urls": [
        "http://newsoffice.mit.edu/2011/fog-harvesting-0421",
        "http://www.nature.com/nature/journal/v414/n6859/full/414033a0.html",
        "http://www.nbdnano.com/"
    ],
    "organizations": [
        "MIT",
        "FogQuest",
        "NBD Nano",
        "Legatum Center for Development and Entrepreneurship",
        "University of Nevada, Las Vegas"
    ],
    "applications": [
        "Rural drinking-water supply",
        "Agricultural fog harvesting",
        "Industrial mist removal",
        "Improved condensation in power-plant heat exchangers"
    ],
    "limitations": [
        "Performance depends on local fog frequency and density",
        "Coating durability under UV, salt spray, and abrasion",
        "Initial material and installation costs",
        "Scaling up mesh area while maintaining optimal airflow"
    ],
    "open_questions": [
        "What is the optimal combination of hydrophobic/hydrophilic materials for different climates?",
        "How does long-term environmental exposure affect coating performance?",
        "Can the technology be economically viable for large-scale municipal water supply?",
        "What are the best manufacturing methods for low-cost, durable mesh coatings?"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "In some field tests, fog harvesters have captured one liter of water (roughly a quart) per one square meter of mesh, per day.",
        "By coating meshes with NBD Nano's hydrophobic coating, NBD Nano is able to consistently increase the rate of fog harvesting in coastal areas. Recent data suggest the NBD Nano coating can improve capture rates by 5x in fog events.",
        "FogQuest workers say there is more to fog harvesting than technology, however. ... They have installed 36 mesh nets in the mountaintop village of Tojquia, Guatemala, and supplies water for 150 people."
    ]
}