Wind Professionals

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Comment by Kelly McCoy on May 15, 2009 at 3:32pm

Hello Wind Professionals,

I am very interested in everything wind, although I am still learning about the industry. Any guidence is welcome and appreciated.

Thank you,
Kelly McCoy

Comment by Jimmy Haley on December 29, 2008 at 8:26pm

Daniel,

Thanks for the breakdown of wind turbines. What exactly do you do on the VAWT front? Down here in San Diego, Helixwind is starting installations this next quarter on their residential VAWTs. Different design from the Windspire, but effective nonetheless.

Comment by DANIEL B FROMHOFF on December 24, 2008 at 3:00pm

WIND TURBINES – HOW IT WORKS
It's hard sometimes to imagine air as a fluid. It just seems so ... invisible. But air is a fluid like any other except that its particles are in gas form instead of liquid. And, when air moves quickly, in the form of wind, those particles are moving quickly. Motion means kinetic energy, which can be captured, just like the energy in moving water can be captured by the turbine in a hydroelectric dam. In the case of a wind-electric turbine, the turbine blades are designed to capture the kinetic energy in wind. The rest is nearly identical to a hydroelectric setup: When the turbine blades capture wind energy and start moving, they spin a shaft that leads from the hub of the rotor to a generator. The generator turns that rotational energy into electricity. At its essence, generating electricity from the wind is all about transferring energy from one medium to another.
Wind power all starts with the sun. When the sun heats up a certain area of land, the air around that land mass absorbs some of that heat. At a certain temperature, that hotter air begins to rise very quickly because a given volume of hot air is lighter than an equal volume of cooler air. Faster-moving (hotter) air particles exert more pressure than slower-moving particles, so it takes fewer of them to maintain the normal air pressure at a given elevation (see How Hot Air Balloons Work to learn more about air temperature and pressure). When that lighter hot air suddenly rises, cooler air flows quickly in to fill the gap the hot air leaves behind. That air rushing in to fill the gap is wind.
If you place an object like a rotor blade or sail in the path of that wind, the wind will push on it, transferring some of its own energy of motion to the object. This is how a wind turbine captures energy from the wind. The same thing happens with a sail boat. When moving air pushes on the barrier of the sail, it causes the boat to move. The wind has transferred its own energy of motion to the sailboat.
Parts of a Wind Turbine
The simplest possible wind-energy turbine consists of three crucial parts:
• Rotor blades - The blades are basically the sails of the system; in their simplest form, they act as barriers to the wind (more modern blade designs go beyond the barrier method). When the wind forces the blades to move, it has transferred some of its energy to the rotor.
• Shaft - The wind-turbine shaft is connected to the center of the rotor. When the rotor spins, the shaft spins as well. In this way, the rotor transfers its mechanical, rotational energy to the shaft, which enters an electrical generator on the other end.
• Generator - At its most basic, a generator is a pretty simple device. It uses the properties of electromagnetic induction to produce electrical voltage - a difference in electrical charge. Voltage is essentially electrical pressure - it is the force that moves electricity, or electrical
• Current flows from one point to another. So generating a voltage is in effect also generating a current. A simple generator consists of magnets and a conductor. The conductor is typically a coiled wire.
• Inside the generator, the shaft connects to an assembly of permanent magnets that surrounds the coil of wire. In electromagnetic induction, if you have a conductor surrounded by magnets,
• In addition, one of those parts is rotating relative to the other; it induces voltage in the conductor. When the rotor spins the shaft, the shaft spins the assembly of magnets, generating voltage in the coil of wire. That voltage drives electrical current (typically alternating current, or AC power) out through power lines for distribution. (See How Electromagnets Work to learn more about electromagnetic induction, and see How Hydropower Plants Work to learn more about turbine-driven generators.)
Modern Wind-power Technology
When we talk about modern wind turbines, we are looking at two primary designs: horizontal-axis and vertical-axis. Vertical-axis wind turbines (VAWTs) are pretty rare. The only ones currently in commercial production in North America are the WINDSPIRE with 20’ vertical sails and a rated output of 1.2kW, which are primarily for residential use. The ECO 1200 with 10’ vertical blades and a rated output from 1.2 KW also. These are roof mounted but both are of excellent design and well engineered to function at low heights and at small winds, starting at 5meters/second or 11 miles/hour. Both generate electricity for about $0.4 to $0.8 per kilowatt/hour. All surplus energy generated is sold to FPL at the same price, making it very cost effective. With these two systems there is virtually no building power require that cannot be filled by Renewable Energy Systems, Inc. (RESI)



In a VAWT, the shaft is mounted on a vertical axis, perpendicular to the ground. VAWTs are always aligned with the wind, unlike their horizontal-axis counterparts, so there is no adjustment necessary when the wind direction changes; VAWTs are generally less efficient than HAWTs. On the upside, all equipment is at ground level for easy installation and servicing.
Globally, at least 50,000 wind turbines are producing 50 billion kilowatt-hours (kWh) annually.