The sleek, elegant EWICON prototype installed on the TU Delft campus resembles a contemporary sculpture, demonstrating how the bladeless windmill could blend aesthetically into an urban environment. Courtesy of Mecanoo
The bladeless windmill’s developers believe their creation may offer a more palatable alternative to conventional wind turbine farms, which the Dutch public has rejected because of their operating noise, blade shadows, and aesthetics.
April 30, 2013—Engineers in the Netherlands at the Delft University of Technology (TU Delft) have developed a 21st-century version of the country’s iconic structure: the windmill.
Led by Dhiradi Djairam, an assistant professor in the electrical engineering and computer science department, the TU Delft team has created a bladeless windmill with no moving parts that uses charged water particles to generate electricity. Dubbed the EWICON (Electrostatic WInd energy CONverter), the high-tech windmill takes the form of a rectangle with rounded corners. The rectangle has a tubular steel frame and when stood upright suggests the letter O or a zero; the frame is mounted on a supporting post that is affixed to an insulated metal plate. Perforated and insulated steel tubes run horizontally from one side of the frame to the other, and the tubes are equipped with nozzles with high-voltage negative electrodes.
“The EWICON operates on the concept of moving charged particles in an electric field,” Djairam explains. Water is pumped up through the post and across the electrodes and is continuously sprayed from the nozzles in the horizontal tubes. Water droplets become positively charged as they are sprayed, and the wind blows the charged droplets away from the system. The insulated metal mounting plate acts as a capacitor, and it is charged as the droplets are blown away.”
So far the team has constructed working EWICON models in the lab, and last month a 2 by 4 m nonoperational prototype was erected in front of the electrical engineering and computer science department’s building. The prototype’s elegant design, the work of the Delft-based architecture firm Mecanoo, “portrays the synergy between design and engineering,” according to Arno Ottevanger, a spokesperson for Mecanoo, who responded in writing to questions posed by Civil Engineering online. “Our goal was to show that a wind converter can be a part of modern design, without it being showy like a traditional windmill, but instead opting for a calm and collected look,” Ottevanger said.
Ultimately, the EWICON’s developers and designers believe that their creation will gain wide acceptance for a range of applications. “Thanks to the greatly reduced wear and tear [from having no moving parts], lower maintenance costs, and zero noise pollution or shadow casting, the EWICON can be installed in wind farms on land or sea and can also be integrated onto the roof of a tall building,” Ottevanger noted. Mecanoo architects may put the concept to a test, as they have incorporated two of the converters into the roof in their proposed design for a new city hall in Rotterdam. The converters will form the zeros in the building’s street address, which is 010.
Mecanoo’s proposed design for Rotterdam’s new city hall—with
two bladeless windmills on the roof representing the zeroes in the
building’s address—illustrates the range of potential applications
for the technology. Courtesy of Mecanoo
Another point in the EWICON’s favor is the absence of moving parts, which means potentially lower construction costs than for conventional wind turbines, according to Djairam. “I see the potential for using the EWICON in applications where otherwise wind energy would not be considered,” he added.
But determining the optimal applications for the EWICON is still in the future. For now, the TU Delft team has several challenges to overcome before the technology is commercially viable. The first is scaling up the mechanism to give it a significant generating capacity. “Output is proportional to the size of the frame, so to increase the output, we need to make the device bigger,” Djairam explained. “Theoretically, an EWICON could be similar in size to conventional wind turbines, but we have not yet investigated the scale effects.”
The system’s efficiency is another challenge. Pumping the water and generating the spray require energy. At present the EWICON’s efficiency is just 1 to 3 percent, compared with 50 percent for a conventional wind turbine. Djairam and his team are targeting a more modest goal of 10 to 20 percent. Even so, achieving that level may require applying a different technology to create the charged droplets or replacing the tubes with a more efficient medium.
One possibility would be to replace the steel tubes with charged copper wire. Assuming that the system could replicate nature, wetting the wire would cause a spray of charged droplets. The amount of electric charge generated would be determined by the amount of liquid present and the wind speed. Since only a conductor, a liquid feed, and a high-voltage input would be required, this model could be more scalable than the more sophisticated hollow-tube version and therefore of greater interest to potential investors.
Even after these issues are resolved, an energy distributor would have to address several connection issues. Because the system creates a high voltage with a low current, the energy would have to be scaled down to a more manageable voltage level for normal residential or industrial uses. “It also will require conversion from DC, as it is produced, to AC so that the energy can be transferred to the grid,” Djairam adds.
The EWICON has attracted the attention of such Dutch electricity distribution companies as Eneco and of firms that construct wind farms. The TU Delft team is formulating proposals for the next phase of development and is investigating new funding sources. With additional research and development support, Djairam estimates that the EWICON technology is six to seven years from commercial availability.