A Better Way to Shed Water for Condensers, Desalination Operations
MIT released a brief video demonstrating the findings.

Researchers at MIT, Cambridge, Mass., have found that lubricated, nano-textured surfaces improved performance of condensers in power and desalination plants. The research is described in a paper published online in the journal ACS Nano.

The key to the improved hydrophobic surface is a combination of microscopic patterning — a surface covered with tiny bumps or posts just 10 mm (millionths of a meter) across, about the size of a red blood cell — and a coating of a lubricant such as oil. The researchers found that the tiny spaces between the posts hold the oil in place through capillary action. MIT released a brief video demonstrating the findings.

The team discovered that droplets of water condensing on this surface moved 10,000 times faster than on surfaces with just the hydrophobic patterning. The speed of this droplet motion is key to allowing the droplets to fall from the surface so that new ones can form, increasing the efficiency of heat transfer in a power plant condenser or the rate of water production in a desalination plant.

The amount of lubricant required is minimal: It forms a thin coating and is securely pinned in place by the posts. Any lubricant that is lost is easily replaced from a small reservoir at the edge of the surface.

The system is easily manufactured because it does not depend on any particular configuration of the tiny textures on the surface, as long as they have about the right dimensions.

Researchers plan further research to quantify exactly how much improvement is possible by using the new technique in power plants.