NYAS Podcast: Ducted Turbines International
In this podcast episode, the New York Academy of Sciences takes a look at some of the fascinating and innovative work that researchers are doing in New York State’s Proof of Concept Centers, including NEXUS-NY 2016 graduate, Ducted Turbines International (DTI). DTI is a clean energy company trying to create more efficient and effective wind turbines, which involves creating a product that advances the current standards of technology, making a viable commercial impact, and also doing real good in the world – all at the same time.
Dr. Ken Visser is the associate professor of mechanical and aeronautical engineering at Clarkson University, and DTI’s Chief Technical Officer. He explains how a wind turbine is essentially a device that detracts energy in the wind and converts it from moving air into electrical energy. This energy can then be used in a variety of ways, from charging a battery to putting it back into the grid.
“All turbines are not created equal. There are drag and lift-driven turbines. A lift-driven machine uses a surface that aerodynamically generates lift, just like an airplane wing. If you do that correctly, you will generate much more torque, which is used to drive the generator,” said Dr. Visser. DTI is trying to get even more out of this process by using ducts, or round tubes, that completely surround the blades of the turbine, and according to Dr. Visser, these ducts have a lot of advantages. “If we put a duct around a rotor it improves the power performance and energy capture. It can also help with aerodynamics of the rotor. That duct acts as a pump and draws in more air and runs it through the rotor, which produces a larger amount of wind, and generates more energy.”
DTI built a prototype last year that they tested at the University of Waterloo. “For that prototype, our rotor diameter was 2.5 meters because we wanted to have the same size as a commercially available turbine that you can buy today,” said Dr. Visser. At a given wind speed of 9mm per second, that commercial turbine would put out 750 watts. “When we put our duct around our rotor blades of the same size, the output jumped to about 1950 watts. So when you then measure the power curve, which results from that wind turbine, the amount of annual energy produced is more than twice that of a traditional wind turbine,” he added.
As amazing as the increased output is, this process has never outweighed the increased costs associated with building the more efficient turbines, and therefore the process has never been proven economically plausible given the added weight and drag force to the machine. “We don’t just have the drag of the rotor, we have the drag of the wind duct and we have to account for these areas in the structural loading on the tower and foundation,” said Dr. Visser. “We can generate twice as much energy, but if it costs twice as much, than we haven’t gained anything. We might as well put up two turbines.”
Herein lies the real challenge DTI is facing – how to design a more efficient wind turbine that is inexpensive enough for someone to actually want to buy it. This is exactly the type of training that New York state proof-of-concept centers like NEXUS-NY encourages scientists to answer, and Dr. Visser’s team is approaching this challenge from several angles. “We can probably for a number of reasons reduce the costs compared to a turbine that would generate the equivalent amount of energy because our idea is lighter. We need a smaller generator to do the same thing, and we don’t need a crane to put it up, so installation costs tend to go down,” he explained.
This has also led to DTI to concentrate on creating smaller turbines that would be used to power a small building or even individual homes instead of huge wind farms that supply power grids. That said, wind turbines cost $65,000 on average. If it costs a consumer only $200 / month to get power from the grid, it would take roughly 27 years to earn back their initial investment. Dr. Visser believes these capital costs are discouraging, and therefore asks customers, “What if you can get your money back in five years?” The responses have been positive, so that has become DTI’s target.
“I’m excited, because if we can get this technology out in the world as a commercially viable product, it will really change the face of the small wind industry,” said Dr. Visser.
This podcast is made possible by the New York State Energy Research and Development Authority (NYSERDA), PowerBridgeNY and NEXUS-NY.
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