Vertical Axis Wind Turbines (VAWT) versus Horizontal Axis Wind Turbines (HAWT)

Vertical Axis Wind Turbines (VAWT) or Horizontal Axis Wind Turbines (HAWT)

 Many periodicals, letters and books note the negatives for

Vertical Axis Wind Turbines (VAWT)

but seldom identify negatives for

Horizontal Axis Wind Turbines (HAWT)

By making this comparison, the features of the G3 (VAWT) turbine shall be identified and described.First, a general description of the VAWT.The VAWT spins on a vertical axle with spokes at the top and bottom of the turbine. Wings very similar to aircraft wings are attached between these spokes and pivot controlled by a furling apparatus. The relatively light turbine assembly is mounted on a tower. At the base of the tower, ground level, is the alternator.
Furling refers to storing or securing sails or flags out of the wind. For turbines, it is the function of shutting down and turning to reduce damaging forces of high winds.
HAWTs furl by braking and stopping the turbine, rotating the blades to neutral and rotating the complete head, blades and power house broadside to the wind. The top of a HAWT is very heavy and does not rotate rapidly. Twenty three(23) of twenty five(25) San Diego Gas and Electric turbines, fifty (50) miles east of San Diego were damaged by a seventy (70) mile per hour wind gust that they could not furl fast enough to avoid.
Myth-VAWTs do not furl:

Wrong. The G3 VAWT can pivot the wings which overlap each other to producing a reduced diameter round object. Since each wing is light, it pivots rapidly and is able to furl in a very short time.
Since the G3 VAWT is able to close up in high winds, it is not necessary to close completely allowing it to produce power in high winds. A control, monitors the wind conditions and adjusts the wings accordingly, regardless of wind intensity. As long as the G3 VAWT is built to withstand high winds, there is no reason not to draw power from it. But HAWTs shut down at twenty-eight (MPH) miles per hour. The G3 VAWT never shuts down.

Myth-VAWT: Are structurally weak. -Wrong.

 HAWT have very long cantilever blades attached on one end. VAWT blades or wings are attached at both ends requiring less structure, less weight for comparable structural integrity. The rotation speed causing centrifugal force on the wings is not difficult to design for, since the rotational speed is not great, especially for large turbines. The megawatt turbine is expected to have a sixty (60) foot diameter. According to our research, a floating turbine, that is; a turbine producing no power consequently, no load, rotates with a peripheral speed about 25% greater that the wind speed.The sixty (60) foot diameter turbine has a 188.5 foot circumference. In a 100 mile per hour wind, the rotor would turn at fifty eight(58) RPM. Under load, producing power, the rotational speed would be thirty(30) RPM.

Myth-VAWTs are inherently inefficient since during rotation, half the blades are traveling with the wind and half the blades are traveling against the wind.

First, the statement is true, but is not a negative, in fact it is an advantage. As any sailor or aviator would recognize, the blade or wing angular to the wind produces lift and in this case, drive. The side rotating with the wind produces less power. HAWTs actually require input power to start the rotors turning in order to produce the lift in conjunction with the wind to produce power. A study by O. Agren and M. Legion of the American Institute of Physics addresses this phenomenon for open VAWTs. The G3 VAWT is closed resulting in low speed high torque like a Savonius turbine and high speed efficiency of a Darreius turbine making this design omni-directional and self starting requiring no external power to operate.

 Second, the truth: HAWTs are not omni-directional as VAWTs are. The blades, rotor and power house must rotate to face the wind to operate. HAWTs produce a vortex in the wind causing buffeting and turbulence following the turbine. The flow through a VAWT is laminar, slightly pulsed and quickly smoothed with no vortex.

 HAWTs kill birds. The blade tips for a one hundred fifty(150) foot blade at only fifteen(15) RPM travel at one hundred sixty (160) miles per hour and rotate perpendicular to the flow of the wind, which is typically the direction of bird flight. Birds traveling twenty (20) miles per hour are seldom broadsided by a blade. At the blade tip is created an invisible vortex wind of 170 to 200 MPH which damages the birds respiratory system and the bird suffers a horrible death of pain and asphyxiation. This vortex is the sound of the turbine.

G3 VAWTs are closed and very visible and rotating about an axle with a peripheral speed slightly faster than the wind. G3 VAWTs do not kill birds. In fact, swallows have nested and raised a family in the cooling blower of our prototype.

G3 VAWTs are light at the top allowing assembly on the ground and erection with self contained rigging.

HAWTs require huge cranes and expensive equipment to construct and service the machine.

HAWTs rotors are mounted on lubricated steel bearings driving alternators through gear boxes all located hundreds of feet above ground.

The G3 VAWT will evolve to magnetic levitation, no bearings. No Maintenance. The G3 VAWT transmits power through a vertical drive shaft to a large diameter alternator at ground level without a gear box. No Maintenance.

Third- Other features and developments.

We have developed a power regulator controller applicable to any size turbine.

We have developed a modular alternator allowing for manufacturing of three sizes of modules that can be used on any size turbines of 1 KW through 10KW, 10KW through 100KW and 100KW through 1MW, in conjunction with our regulator to produce power AC or DC. 24 Volt to 4160 Volt, all without a speed increasing gear box.

The G3 VAWT may be equipped with 8 wings, 16 wings or 24 wings in its

present configuration.

Direct any questions to:

Jerry A. Carter {714) 540-6787

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