Sep 24, 2013

New hydrophobic material could benefit power plants, cooling systems.

Steam condensation is key to the worldwide production of electricity and clean water: It is part of the power cycle that drives 85 percent of all electricity-generating plants and about half of all desalination plants globally, according to the United Nations and International Energy Agency. So anything that improves the efficiency of this process could have enormous impact on global energy use.

It has been known for years that making steam-condenser surfaces hydrophobic — that is, getting them to repel water — could improve the efficiency of condensation by causing the water to quickly form droplets. But most hydrophobic materials have limited durability, especially in steamy industrial settings. The new approach to coating condenser surfaces should overcome that problem, the MIT researchers say.

The covalent-bonding process the team developed is significantly more stable than previous coatings, he says, even under harsh conditions.

Tests of metal surfaces coated using the team's process show "a stark difference," Paxson says. In the tests, the material stood up well even when exposed to steam at 100 degrees Celsius in an accelerated endurance test. Typically, the steam in power-plant condensers would only be about 40 degrees Celsius, Varanasi says.

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