Coating technology promises to increase energy efficiency at Power plants
Chemical and mechanical engineers are working together to create a water repellent coating that will increase the efficiency of power plants.
DropWise, the brainchild of two Massachusetts Institute of Technology professors, Kripa Varanasi and Karen Gleason, and two of their students, is a coating technology for heat exchangers in power plants and chemical refineries.
In a power plant, fuel is burned to heat a boiler full of water to create steam, which flows through a turbine. The steam spins the turbine and creates electricity. To limit the amount of water used, the steam is then recycled and recirculated into water via a heat exchanger.
The steam from the turbine flows into the heat exchanger and surrounds metal tubes with cold water flowing inside. The DropWise technology coats the outside of the cold-water tubes, reducing the film that builds up around the tube when the steam condenses into water, allowing more efficient cooling.
The DropWise coating, 2,000 times thinner than a piece of paper, has the potential to offset the same amount of carbon emissions as taking several thousand cars off the road by increasing efficiency, said Adam Paxson, DropWise president and chief executive.
“Heat exchangers are one of the most important pieces in power plants and chemical refineries,” said Paxson, who received his PhD in mechanical engineering from MIT. “Because these systems are used so widely, even small improvements can have massive impacts.”
Paxson said if all steam condensers have a water-repellent coating, it would cut more emissions than the entire global solar and wind industries. Annica Blake, chief operator for DropWise, said the coating”can save an average 500MW power plant hundreds of thousands of dollars per year.”
The innovation is not yet ready – it is still several years away from pilot phase – but DropWise announced two weeks ago a joint development agreement with Henkel AG and Company, a German industrial company. Paxson said Henkel brings its name-brand recognition and global reach to DropWise’s technical expertise.
Blake said the company has spoken with many power plant managers and operators about their options to increase efficiency, especially following President Obama’s Aug. 3 announcement of the Clean Power Plan that focuses on reducing carbon pollution from power plants. While DropWise won’t ensure each power plant meets the regulations, she said it will help the plants comply with the new proposed regulation of cutting emissions 32 percent from 2005 levels by 2030.
“There are a whole bunch of efficiency gains being put into place that they have no idea how to meet,” Blake said. “Technologies are realistic options to be implemented.”