Wind energy is growing more economical and reliable. Vertical axis machines can help meet smaller, local needs for communities with limited resources. These include pumping water, grinding grain, powering workshops and in some cases, generating electricity. Learn about the two main types of vertical axis wind machines in this article:
The lift type (eggbeater, helical and h-rotor)
The Darrieus vertical axis wind turbines often has two or three thin, curved blades, depending on the model. These turn at higher speeds suitable for generating electricity but require much greater skill in design and engineering. The h-type is simply vertical blades. The helical-rotor has complex blades mounted vertically. The h-type and helical style types can also provide the high speeds needed for electricity generation.
The drag type (scooper)
The drag type windmills use paddles, simple vanes or scoops. Drag type wind machines tend to turn more slowly but are more powerful. They can be used to pump water, mill grains, and power businesses or workshops. They can generate electricity but are better for high-torque low speed applications.
The Savonius two-scoop machine looks a bit like the letter “S” in cross section. One side of the scoop experiences less drag when moving against the wind than when moving with the wind. The differential drag causes the Savonius turbine to spin. The asbads of Iran get the same effect with mud walls. Some scoop type wind machines are not good at self-starting at low wind speeds and need a starter that initiates movement at low winds. Scoop machines may appear to be slow and safe but must have a lock for maintenance. One of my friends was almost injured when his homebuilt “simple” Savonius started to turn.
New vertical axis designs from around the world may improve performance and beauty. The KLiux machine is a multi-vane generator, a descendent of the Iranian asbads. The KLiux rotor’s movement is transferred to the permanent magnet generator through a high efficiency speed-increasing planetary gearbox. Both elements are encased in a single steel module to protect them from weathering. This module is located between the rotor and the support. This is one of the more efficient electricity generation machines available today.
The Airloom design (somewhat like the Chinese sails) may resolve several of the problems with vertical axis machines. Airloom’s system will use a series of 11 m long vertical wings attached to a cable running around an oval-shaped track suspended about 25 m off the ground. The blades change orientation as they turn around at the ends of the oval, angling themselves for optimal power as they run down the long side sections, while the power takeoffs harvest the linear motion from the cable to run generators. The expected power generation is 2.5-MW for the commercial-scale version at a third of the cost of a tall horizontal axis machine. Pilot tests are currently underway, with funding from Bill Gates and others.
Innovation in design is essential. It is easy to suggest that there are no new ideas, but it is certain they exist. Multi-machine arrays may be one of the answers, much like the walls of the asbads wind machines of Nashtifan. There are also suggestions for a folding return for the vanes, just like feathering paddles when kayaking.
We’re interested in working with such equipment s