Vertical-axis turbines starts generating at less than 3 m/s
August 18, 2009 by Paul Dvorak
Filed under Small Wind Power, Turbine Design
There are two basic types of wind turbines: vertical and horizontal axis. Each has pros and cons. Horizontal-axis turbines tend to capture more power per square meter of wind, but are noisier, vibrate more, present hazards to birds, require more empty space around them, and must be elevated away from people. Vertical-axis turbines, on the other hand, are quiet and do not need to turn towards the wind to maximize their power output.
The blue cap and base on the Wind Lotus are said to focus the wind onto the blades and therefore improve their energy capture.
Turbines can also be classified as lift turbines and drag designs. Drag turbines simply rotate from the push of the wind. They start easily, but cannot move faster than the push from the wind. Lift turbines use aerodynamic blades to rotate faster than the mere push of the wind would allow, but this class has more difficulty starting.
The Wind Lotus from Leviathan Energy, Los Angeles, is said to have advantages of both. The patent-pending aerodynamic shape is one reason for its good performance. In addition the design uses five blades, whereas almost all lift turbines, whether horizontal or vertical, have three. This translates to more starting power, better balance, and minimal noise.
The aerodynamic design increases wind velocity where it hits the blades letting the turbine produce more power than larger units. The Wind Lotus is said to have a lower cut-in speed than other turbines which increases its cost effectiveness. Cut-in speed is the wind speed at which the turbine starts to produce electricity. The aerodynamic design improves its performance over other turbines so it produces more power. The table presents a few specs.
Turbine said to tolerate 168 mph winds
July 18, 2009 by Paul Dvorak
Filed under Small Wind Power, Wind Watch
The Windspire wind turbine is said to be a low-cost, low-noise appliance for use in urban, suburban, rural, and remote locations. Manufactured Mariah Power, Reno, Nevada, the turbines feature patented equipment to maximizes energy conversion from wind into electric power, regardless of speed or direction.
A high-wind version of a vertical axis wind turbine is said to withstand jetstream-like 168 mph winds and extreme weather conditions. The High Wind Windspire from Mariah Power, Reno, Nevada, will feature a shorter version of the company’s giromill straight blade design and its current generator and inverter. The company plans to sell this new product to government agencies, cellular companies, and ski resorts that require alternative energy equipment for consistent high wind and remote areas. The unit can be grid tied or used in dc form to recharge batteries.
The High Wind Windspire stands 13-ft tall and 4-ft wide. The unit is rated at 1.1 kW at 30 mph and is estimated to produce 2,066 kWh in 15 mph average wind speeds.
“The High Wind Windspire addresses the irony of wind power: a good wind resource is necessary to produce wind energy but too much wind can harm wind turbines,” said company CEO Mike Hess. “The new design allows installing it in areas with extreme winds and survive.” The company says to expect other new products in coming months.
CAD and data management make turbine designer more efficient
June 29, 2009 by Paul Dvorak
Filed under Mechanical Components, Turbine Design
The quietrevolution vertical axis turbine, say developers, was designed in response to demand for turbines that work well in urban environments, where winds speeds are lower and wind directions change frequently.
UK-based wind-energy company quietrevolution says it will use PLM software from Dassault Systèmes, Paris, to improve design and manufacturing of its wind energy generators. Having calculated a mathematically correct shape for its aerodynamically-optimized vertical axis rotor blades, quietrevolution uses Dassault’s Catia to design, engineer, and manufacture its turbines. The company says Catia helps them capitalize on the growing demand for wind turbines by providing an efficient design, development, and production platform that lets it make the most of its resources.
“Product development is the heart of our work,” says quietrevolution Design Manager Richard Kingsley. “In the short time we have been using Catia, it has significantly improved our ability to efficiently complete a design-to-manufacture processes of advanced structures. The software lets us digitally design, sign off, investigate tooling feasibility, build products, and communicate 3D designs. It’s used in our supply chain and lets us exchange native files with partners which leads to more efficient production.”
“Using the best practices developed with manufacturers from other industries lets wind-turbine manufacturers avoid costly trial and error in the real world,” says Dassault’s Director Mike Crow. “The software shortens development cycles while manufacturing stronger products with higher energy outputs by combining design, testing, and manufacturability analysis in a single environment.”
Vertical axis turbine works for small business
May 26, 2009 by Paul Dvorak
Filed under Wind Watch
The company says its vertical axis turbines run silently, less than 5 dB above background noise, and it’s safe for birds and bats
Not all wind turbines are megawatt units. Two designs from HelixWind, San Diego, are said to work in low-wind speeds common around residential areas and small commercial businesses. The developer says its Savonius-turbine design (a vertical axis windmill) catches wind from all directions creating smooth torque to spin an electric generator. Mounted up to 35-ft up, the company says the Helix system creates electricity in winds as low as 10 mph to power a home or business.
The S594 is a commercial scale system for applications on medium to large buildings. Long helical blade scoops, 16-ft high by 4-ft diameter, use a single-pole support for the top bearing. A direct-drive permanent-magnet generator reaches rated power at 200 RPM. Power goes through a grid-tie inverter for use onsite and back into the utility grid for net metering. The company says its design life is 30 years. The table lists a few more specs.
