How Long Must We Wait for the Bladeless Windmill?
After we posted an image of a concept rendering for a bladeless windmill last week, readers had questions. Is it efficient? Cheap? How soon might the EWICON (Electrostatic Wind Energy Converter) be providing wind power from a roof near us?
To get the answers to those questions, I spoke with Dhiradj Djairam, who invented the EWICON for his doctorate at the Delft University of Technology. First thing's first: it's going to be a while before there's a bladeless windmill near you.
Despite an attractive EWICON model designed by Mecanoo Architects (it doesn't generate power, by the way), which stands outside a Delft faculty building, there's still some work to be done before EWICON technology can be scaled up to a useful size and widely reproduced.
In particular, the windmill, which creates energy by letting charged water particles blow against the direction of an electric field, needs to be made more efficient. (Find out more about how the EWICON works in this short animation, or for the more technically inclined, through this presentation [PDF].)
What primarily needs improvement, Djairam says, is the process by which the water droplets are charged. He estimates it could take four or five years of research (and grants to support that research) to develop electrospray technology that would be compatible — cheap, efficient, reliable — with the requirements of a mass-produced machine.
There are other questions too: what would be the side effects for living things subjected to hours or days of electrically charged mist? (A few minutes of electromist, Djairam says, is no problem.) Could the EWICON work in the cold? What kind of risk would high-voltage bars pose to birds?
But once those kinks have been straightened out, the EWICON could be innovative in ways beyond those I described last week. For one thing, it need not be expensive: it has no moving parts, which simplifies construction and nearly eliminates maintenance, and the technology in use is for the most part relatively straightforward. "There are a lot of different fields coming together, but none of these fields are particularly high-tech," Djairam says.
For another, the EWICON has also been designed to work with salt water. And lest our imagination be constrained by the sleek, ovaloid Mecanoo model, the EWICON could exist in a variety of shapes. Unlike the rotating windmill, whose territory is of course circular, the EWICON could be built large or small, in massive discs or in slender strips climbing the sides of buildings.
Top image courtesy of Dhiradj Djairam.