FABRICATION OF VERTICAL AXIS WIND TURBINE full pdf report | MECHANICAL PROJECT
If the efficiency of a wind turbine is increased, then more power can be generated thus decreasing the need for expensive power generators that cause pollution. This would also reduce the cost of power for the common people. The wind is literally there for the taking and doesn't cost any money. Power can be generated and stored by a wind turbine with little or no pollution. If the efficiency of the common wind turbine is improved and widespread, the common people can cut back on their power costs immensely.
We know that for windmills to operate there must be wind, but how do they work? Actually there are two types of windmills -- the horizontal axis windmills and the vertical axis windmills. The horizontal axis windmills have a horizontal rotor much like the classic Dutch four-arm windmill. The horizontal axis windmills primarily rely on lift from the wind. As stated in Bernoulli's Principle, "a fluid will travel from an area of higher pressure to an area of lower pressure." It also states, "as the velocity of a fluid increases, its density decreases." Based upon this principle, horizontal axis windmill blades have been designed much like the wings of an airplane, with a curved top. This design increases the velocity of the air on top of the blade thus decreasing its density and causing the air on the bottom of the blade to go towards the top ... creating lift. The blades are angled on the axis as to utilize the lift in the rotation. The blades on modern wind turbines are designed for maximum lift and minimal drag.
|Fig. Assembly Of Wind mill|
VARAIBLES FOR VERTICAL AXIS WIND MILL
• Wind Speed
This is very important to the productivity of a windmill. The wind turbine only generates power with the wind. The wind rotates the axis (horizontal or vertical) and causes the shaft on the generator to sweep past the magnetic coils creating an electric current.
• Blade Length
This is important because the length of the blade is directly proportional to the swept area. Larger blades have a greater swept area and thus catch more wind with each revolution. Because of this, they may also have more torque.
• Base Height
The height of the base affects the windmill immensely. The higher a windmill is, the more productive it will be due to the fact that as the altitude increases so does the wind speed.
• Base Design
Some base is stronger than others. Base is important in the construction of the windmill because not only do they have to support the windmill, but they must also be subject to their own weight and the drag of the wind. If a weak tower is subject to these elements, then it will surely collapse. Therefore, the base must be identical so as to insure a fair comparison.
• Tip Speed Ratio
The tip speed ratio is very important. The tip speed ratio is directly proportional to the windmill's productivity. It is how many times the blades rotate greater than the wind speed.
|Fig. Block Diagram Of Wind Mill Power Generation|
ADVANTAGE OF VERTICAL AXIS WIND TURBINE OVER HORIZONTAL AXIS WIND TURBINE
There are several reasons why I would choose a vertical axis wind turbine over a horizontal axis windmill .
• First, they are mounted lower to the ground making it easy for maintenance if needed.
• Second, they start creating electricity at speeds of only 6 mph. And
• Third, they may be able to be built at locations where taller structures, such as the horizontal type, can't be.
• Higher power utilization-- 20% higher than HAWT.
• Lower noise level--only 27-37 DB, suitable for your living condition.
• Safer operation--Spin at slower speeds than horizontal turbines, decreasing the risk of injuring birds and also decreasing noise level.
• Simpler installation and maintenance-- besides the traditional installation site, it can be mounted directly on a rooftop, doing away with the tower and associated guy lines.
• Not affected by orientation variation—no matter the wind blow from any orientation, VAWT can work without regard to its face.
• Economical and practical-Although one-time investment expenses is larger, but you don’t have to pay higher tariffs forever.
• It is a renewable source of energy.
• Wind power system are non-polluting so it has no adverse influence on the environment.
• Wind energy system avoid fuel provision and transport.
• On a small scale up to a few kilowatt system is less costly.
• On a large scale costs can be competitive conventional electricity and lower costs could be achieved by mass production.
• They are always facing the wind - no need for steering into the wind.
• Have greater surface area for energy capture -can be many times greater.
• Are more efficient in gusty winds – already facing the gust.
• Can be installed in more locations - on roofs, along highways, in parking lots.
• Can be scaled more easily - from milliwatts to megawatts.
• Can have low maintenance downtime - mechanisms at or near ground level.
• Produce less noise - low speed means less noise
• The rotor can take wind from every direction.