Vortex Bladeless is an aerogenerator that harnesses wind energy from a phenomenon of vorticity called Vortex Shedding. Basically, Vortex technology consists of a cylinder fixed vertically with an elastic rod. The cylinder oscillates in the wind, which then generates electricity through an alternator system. In other words, it is a wind turbine which is not actually a turbine.
The outer cylinder is designed to be largely rigid and has the ability to vibrate, remaining anchored to the bottom rod. The top of the cylinder is unconstrained and has the maximum amplitude of the oscillation. The structure is built using resins reinforced with carbon and/or glass fiber, materials used in conventional wind turbine blades.
The rod’s top supports the mast and it’s bottom is firmly anchored to the ground. It is built of carbon fiber reinforced polymer, which provides a great fatigue resistance and it has a minimal energy leak when oscillating.
Naturally, the design of such wind turbine is quite different from a traditional turbine. Instead of the usual tower, nacelle and blades, our device has only a mast made of lightweight materials over a base. This reduces the usage of raw materials and the need for a deeper foundation.
Our bladeless wind turbine captures the energy from the wind by a resonance phenomenon produced by an aerodynamic effect called vortex shedding. In fluid mechanics, as the wind passes through a blunt body, the flow is modified and generates a cyclical pattern of vortices. Once the frequency of these forces is close enough to body’s structural frequency, the body starts to oscillate and enters into resonance with the wind. This is also known as Vortex Induced Vibration (VIV).
Retrieved from: Duke University
This VIV phenomenon is commonly avoided in structural engineering, aeronautics and architecture. Quite the opposite, Vortex’s technology maximizes this aerodynamic instabilities and wind turbulences, capturing this energy.
Vortex’s mast geometry is specially designed to achieve maximum performance to the average observed wind velocities. It is able to adapt very quickly to wind direction changes and turbulent airflows commonly observed in urban environments.
The disturbance of the downstream wind current is why turbines need to be installed far from each other. This doesn’t affect bladeless wind turbines, any limitation associated with the “shadow effect” is avoided. Furthermore, we expect Vortex devices to work better together, feedbacking each other.
Currently, Vortex generates electricity through an alternator system, made by coils and magnets, adapted to the vortex dynamics, without gears, shafts or any rotating parts. Our Vortex generator is currently considered a “small wind turbine”.
Alternators are a well known technology, altough the way Vortex is using it is innovative and patented. This design allows to reduce maintenance and eliminates the need for greasing.
A. Stator’s fixed part
B. Alternator’s mobile part
C. Stator’s support
The frequency of the Vortex shedding is proportional to the windstream’s velocity, however each structure has its own natural vibration frequency. To match wind frequencies with a device’s natural frequency you should modify the body mass (the more mass the less natural frequency) and the rigidity (the more rigidity, higher frequencies), among other parameters. Therefore, you would need complex mechanisms to vary the natural frequency of that device.
To avoid this, Vortex design uses instead a magnetic confinement system with permanent magnets that increase the apparent stiffness of the system according to their degree of flexion. The degree of flexion grows as long the wind intensifies. We call this “tuning system”.
As a result, Vortex’s patented self-synchronization system allows to capture a wider range of wind speeds with no effort, starting from 2-3m/s aprox. It can automatically vary rigidity and “synchronize ” with the incoming wind speed, in order to stay in resonance without any mechanical or manual interference. This way the aerogenerator’s lock-in range increases.
The Vortex Street effect or Vortex Shedding effect was first described and mathematically formalized by Theodore von Kármán, the genius of aeronautics, in 1911. This effect is produced by lateral forces of the wind on an object immersed in a laminar flow. The wind flow generates a cyclical pattern of vortices, which can become an engineering challenge for slender structures, such as towers, masts and chimneys. One of such examples is the collapse of Tacoma Narrow’s bridge in 1940, USA.
The idea behind Vortex aerogenerator is that it is possible that same forces can be exploited to produce energy. When the the wind vortices matches the natural frequency of the device’s structure it begins resonating, hence oscillating, so the bladeless wind turbine can harness energy from that movement as a regular generator.
You will find lots of examples of the Vortex Shedding effect in daylife. Based on this principle, and bearing in mind some other physical phenomena, such as Betz’s law, finite bodies’ aerodynamics, turbulence regions, wind gradient, etc… the Vortex’s team have created lots of computational models which will shed light on the proper geometry and parameters to develop and improve the efficiency of Vortex design.
Although 2D simulations are very interesting for us, VIV is a 3D phenomenon. Interaction between vortices along the device have been described by other authors. Since ours is a new technology, we have to create new models and confirm their validity. These 3D simulations are based in the Reynolds number, an important dimensionless quantity in fluid mechanics used to help predict flow patterns in different fluid flow situations
A big amount of computation resources are needed. We work hard using Altair’s simulation software trying to find the best way to achieve optimum results with an affordable quantity of computation resources and time. We also collaborate with Barcelona Supercomputing Center using their computational and expertise resources.
Current wind turbine technology need to support very different load levels under variable wind speeds, which puts high mechanical demands on transmitting components such as gears, bearings, bushings or brakes. The multiple moving parts are constantly under wear, which leads to high maintenance costs.
Vortex aerogenerator completely eliminates mechanical elements that can suffer wear by friction. The main materials used for manufacturing Vortex technology are carbon fiber polymers, plastics, steel, neodymium and copper. The working limits of these materials are far away from Vortex’s operational standars.
Vortex Tacoma (2,75m) - Under development, not on sale yet!
Of course, the aerogenerator is not immune to fatigue and stress forces. Fatigue is defined by the weakening of a material caused due to repeatedly applied loads or forces. Vortex turbine’s rod suffers continuated flexion and a material failure could eventually occur. The first products have been designed paying special attention to this issue.
The carbon fiber rod was designed to work at a maximum oscillation amplitude of 2,7º. This implies a very low materials deformation. Computational and mathematical analysis carried out in relation to the component most affected by this phenomenon of fatigue, make us think that Vortex aerogenerator has a huge life span.
One of the main advantages of Vortex technology are the low costs associated with the new technology. We have estimated that Vortex turbines’ levelized cost of energy (LCOE) will be lower, which will allow a faster return on investment. Anyway, further research has to be done on this topic to say with certainity.
This makes this tech highly competitive not only against generations of alternative or renewable energy, but even compared to conventional technologies.
These cost reductions come from a clever design and usage of raw materials. There is no need for a nacelle, support mechanisms and blades, that are usual costly components in the conventional wind generators.
Thanks to be very lightweight and to have the gravity center close to the ground, anchoring or foundation requirements have been reduced significantly compared to regular turbines, easing installation.
In wind energy conversion, power generation is proportional to the swept area of the aerogenerator. Vortex currently sweeps up as much as 30 % of the working area of a conventional 3-blades-based wind turbine of identical height.
As a result, generally speaking we can say Vortex aerogenerators are less power efficient than regular horizontal-axis wind turbines. On the other hand, a smaller swept area allows more Vortex turbines to be installed in the same surface area, compensating the power efficiency with space efficiency in a cheaper way.
The Vortex Tacoma (2,75m) estimated rated power output is 100w.
In urban environments wind airflows are usually very turbulent, this is an issue for regular wind turbines. In addition, the wake of conventional windmills is problematic when installing several wind turbines working together in the same place.
On the other hand, conventional wind turbines need an orientation system to face the incident windstream. Vortex wind generators doesn’t need it anymore due to its circular cross section.
VIV effect is based on fluid turbulences. Consequently, this bladeless turbine will adapt very quiclky to wind direction and intensity changes, no matter the turbulences. A fully developed laminar wind flow is not necessary for a Vortex’s effective operation.
The Vortex technology aims to be a “greener” wind alternative. Athough a more rigorous carbon footprint analysis is needed, bladeless turbines seem to bring some extra advantages from the environmental point of view.
Vortex bladeless is mainly a solution for distributed energy generation. It is perfect to be placed near a house or over the roof. It can work on grid and off grid, and as a part of a hybrid solar installation plus wind generation.
Its simple design and light weight allow a very efficient use of raw materials. No complex manufacturing process is required to build a Vortex aerogenerator. The absence of lubricants makes unnecessary to manage this waste.
The total weight of a Vortex Tacoma is estimated to be less than 12 Kg. Unlike regular rotating-based wind power, with the proper calibration and anchoring we expect Vortex technology to be completely noiseless.
Although small wind turbines usually do not represent an important issue for local wildlife, bladeless turbines’ impact on birds population is expected to be much smaller.
The oscillatory movement of Vortex design is tiny and much less aggressive than the one of traditional wind turbines, so it won’t disturb birds and allows them to have a higher visibility while flying.
The NGO Birdlife is collaborating with us to measure this impact. Wind energy and birds can share the same wind!
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