Welwitschia-inspired wavy surfaces for passive atmospheric water harvesting

Overview

This solution offers a passive, energy-free method for harvesting atmospheric water by mimicking the hierarchical wavy surface structures found on the leaves of Welwitschia mirabilis, a desert plant that survives for over 2,000 years in the Namib Desert. The technology targets both dew and fog capture, addressing a critical need for water supply in arid and water-stressed regions. By combining enhanced airborne water capture with self-directed liquid transport along surface grooves, the design maximizes collection efficiency while minimizing losses from evaporation.

Technical specifications

• Wavy surface geometry: Macroscopic wavy textures induce local air circulation and focused diffusion flux to enhance capture of both airborne droplets and vapor.
• Dual-mode harvesting: Capable of collecting liquid from both humid air flow (fog) and condensation (dew) simultaneously, a capability not achieved by current state-of-the-art functional surfaces.
• Self-transport mechanism: Capillary pressure differences drive collected liquid from ridges to valleys, with gravity-assisted transport along grooves for continuous collection.
• Evaporation reduction: Groove geometry and directional transport minimize evaporative loss during collection.
• Scalable manufacturing: Large-scale sheet metal forming processes enable modular panels greater than 10 m by 10 m, designed for tilted roof deployment.
• Validation status: Preliminary tests on surfaces larger than 100 mm by 100 mm in condensation chambers and wind tunnels have demonstrated collection rates exceeding previously reported benchmarks.

Technology readiness level

The technology is at an early-to-mid stage of development. Laboratory-scale prototypes (100 mm × 100 mm) have been validated and have shown superior performance compared to prior published results. Next steps include systematic investigation of multiscale wavy geometries under varied flow conditions, optimization of directional transport mechanisms, and scale-up to roof-sized modular panels. Large-scale manufacturing feasibility will be explored using Northwestern University's existing sheet metal forming infrastructure.