Small wind turbine
Encyclopedia
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
output, lifetime bearings and use a vane to point into the wind. Larger, more costly turbines generally have geared power trains, alternating current output and are actively pointed into the wind. Direct drive generators are also used on some large wind turbines.
North America
Small wind turbines added a total of 17.3 MW of generating capacity throughout the United States in 2008, according to the American Wind Energy AssociationAmerican Wind Energy Association
Formed in 1974, the American Wind Energy Association is a Washington, D.C.-based national trade association representing wind power project developers, equipment suppliers, service providers, parts manufacturers, utilities, researchers, and others involved in the wind industry.With over 2,500...
(AWEA). That growth equaled a 78% increase in the domestic market for small wind turbines, which are defined as wind turbines with capacities of 100 kW or less. AWEA's "2009 Small Wind Global Market Study", published in late 2009 May, credited the increase in part to greater manufacturing volumes, as the industry was able to attract enough private investment to finance manufacturing plant expansions. It also credited rising electricity prices and greater public awareness of wind technologies for an increase in residential sale. But a poll of small wind manufacturers found that the growth in 2008 might be only a glimmer of things to come, as the companies projected a 30-fold growth in the U.S. small wind market within as little as five years, despite the global recession. The U.S. small wind industry also benefits from the global market, as it controls about half of the global market share. U.S. manufacturers garnered $77 million of the $156 million that was spent throughout the world on small wind turbine installations. A total of 38.7 MW of small wind power capacity was installed globally in 2008.
Europe
Some households in rural or suburban parts of the UK can opt for a wind turbine with inverter to supplement local grid power.Installation
To see an animation of a small wind turbine being assembled see Wind Turbine 24v's websiteTurbines are often mounted on a tower to raise them above any nearby obstacles. One rule of thumb is that turbines should be at least 30 feet (9 m) higher than anything within 500 feet (152 m). Better locations for wind turbines are far away from large upwind obstacles. Measurements made in a boundary layer wind tunnel have indicated that significant detrimental effects associated with nearby obstacles can extend up to 80 times the obstacle's height downwind. However, this is an extreme case. Another approach to siting a small turbine is to use a shelter model to predict how nearby obstacles will affect local wind conditions. Models of this type are general and can be applied to any site. They are often developed based on actual wind measurements, and can estimate flow properties such as mean wind speed and turbulence levels at a potential turbine location, taking into account the size, shape, and distance to any nearby obstacles.
A small wind turbine can be installed on a roof. Installation issues then include the strength of the roof, vibration, and the turbulence caused by the roof ledge. Small-scale rooftop turbines suffer from turbulence and rarely generate significant amounts of power, especially in towns and cities.
Types
Smaller scale turbines for residential scale use are available, they are usually approximately 7 to- in diameter and produce electricity at a rate of 300 to 10,000 watts at their tested wind speed. Some units have been designed to be very lightweight in their construction, e.g. 16 kilograms (35 lb), allowing sensitivity to minor wind movements and a rapid response to wind gusts typically found in urban settings and easy mounting much like a television antenna. It is claimed, and a few are certified, as being inaudible even a few feet (about a metre) under the turbine.The majority of small wind turbines are traditional horizontal axis wind turbines, but Vertical axis wind turbine
Vertical axis wind turbine
Vertical-axis wind turbines are a type of wind turbine where the main rotor shaft is set vertically and the main components are located at the base of the turbine...
s are a growing type of wind turbine in the small-wind market. These turbines, by being able to take wind from multiple dimensions, are more applicable for use at low heights, on rooftops, and in generally urbanized areas. Their ability to function well at low heights is particularly important when considering the cost of a high tower necessary for traditional turbines. All big companies in this industry, such as WePower, Urban Green Energy
Urban Green Energy
Urban Green Energy is a small wind turbine manufacturer, founded in 2007. UGE specializes in the design, manufacturing, and testing of vertical axis wind turbines, which it primarily markets as distributed energy solutions for homes and businesses...
, Mariah Power, and Helix Wind, have reported sharply increasing sales over the previous years.
Dynamic braking
Dynamic braking
Dynamic braking is the use of the electric traction motors of a railroad vehicle as generators when slowing the Locomotive. It is termed rheostatic if the generated electrical power is dissipated as heat in brake grid resistors, and regenerative if the power is returned to the supply line...
regulates the speed by dumping excess energy, so that the turbine continues to produce electricity even in high winds. The dynamic braking resistor may be installed inside the building to provide heat (during high winds when more heat is lost by the building, while more heat is also produced by the braking resistor). The location makes low voltage (around 12 volt) distribution practical.
Local use
In the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, residential wind turbines with outputs of 2–10 kW, typically cost between $12,000 and $55,000 installed ($6 per watt), although there are incentives and rebates available in 19 states that can reduce the purchase price for homeowners by up to 50 percent, to ($3 per watt). The US manufacturer "Southwest Windpower," estimates a turbine to pay for itself in energy savings in 5 to 10 years.
The American Wind Energy Association
American Wind Energy Association
Formed in 1974, the American Wind Energy Association is a Washington, D.C.-based national trade association representing wind power project developers, equipment suppliers, service providers, parts manufacturers, utilities, researchers, and others involved in the wind industry.With over 2,500...
has released several studies on the small wind turbine market in the U.S. and abroad, showing that the U.S. continues to dominate the Small Wind industry.http://www.awea.org/smallwind/documents/AWEASmallWindMarketStudy2007.pdf According to another organization, the World Wind Energy Association, it is difficult to assess the total number or capacity of small-scaled wind turbines, but in China alone, there are roughly 300,000 small-scale wind turbines generating electricity.
The dominant models on the market, especially in the United States, are horizontal-axis wind turbines (HAWT).
Parts
- BladesPropeller (aircraft)Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
- Hub
- DC generatorElectrical generatorIn electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...
- DiodeDiodeIn electronics, a diode is a type of two-terminal electronic component with a nonlinear current–voltage characteristic. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material connected to two electrical terminals...
- Mount
- WireWireA wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Standard sizes are determined by various...
s - TailTailThe tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
International consumer label
To enable consumers to make an informed decision when purchasing a small wind turbine, a method for consumer labeling has been developed by IEA Wind Task 27 in collaboration with IEC TC88 MT2. In 2011 IEA Wind published a Recommended Practice, which describes the tests and procedures required to apply the label.DIY and open source wind turbines
Some hobbyHobby
A hobby is a regular activity or interest that is undertaken for pleasure, typically done during one's leisure time.- Etymology :A hobby horse is a wooden or wickerwork toy made to be ridden just like a real horse...
ists have built wind turbines from kits, sourced components, or from scratch.
Do it yourself
Do it yourself
Do it yourself is a term used to describe building, modifying, or repairing of something without the aid of experts or professionals...
or DIY-wind turbine construction has been made popular by magazines such as OtherPower and Home Power, and websites such as Instructables
Instructables
Instructables is a website specializing in user-created and uploaded do-it-yourself projects, which other users can comment on and rate for quality. It was created by Eric Wilhelm, a mechanical engineer, and launched in August 2005. Instructables is dedicated to step-by-step collaboration among...
, and by TV-series as Jericho
Jericho (TV series)
Jericho is an American action/drama series that centers on the residents of the fictional town of Jericho, Kansas, in the aftermath of nuclear attacks on 23 major cities in the contiguous United States...
and The Time Machine
The Time Machine (2002 film)
The Time Machine is a 2002 American science fiction film loosely adapted from the 1895 novel of the same name by H. G. Wells, and the 1960 film screenplay by David Duncan...
.
DIY-made wind turbines are usually smaller (rooftop) turbines of ~ 1 kW or less. These small wind turbines are usually tilt-up or fixed
Fixed
Fixed may refer to:* Fixed , EP by Nine Inch Nails* Fixed , a collection of monospace bitmap fonts that is distributed with the X Window System* Fixed, subjected to neutering...
/guyed towers. However, larger (freestanding) and more powerful windtubines are sometimes built as well. In addition, people are also showing interest in DIY-construction of wind turbines with special designs
Special wind turbines
As of 2010, the most common type of wind turbine is the three-bladed horizontal-axis wind turbine .This article deals with various types of wind turbine that differ from the standard type...
as the Savonius, Panemone
Panemone
A panemone windmill is a type of vertical axis wind turbine. It has a rotating axis positioned vertically, while the wind-catching blades move parallel to the wind. By contrast, the shaft of a horizontal axis wind turbine points into the wind while its blades move at right-angles to the wind's...
, wind turbine to boost power generation. When compared to similar sized commercial wind turbines, these DIY turbines tend to be cheaper.
Through the internet, the community is now able to obtain plans to construct DIY-wind turbines. and there is a growing trend toward building them for domestic requirements. The DIY-wind turbines are now being used both in developed countries and in developing countries, to help power homes, residences and small businesses. At present, organizations as Practical Action
Practical Action
Practical Action is a development charity registered in the United Kingdom which works directly in four regions of the developing world – Latin America, East Africa, Southern Africa and South Asia, with particular concentration on Peru, Kenya, Sudan, Zimbabwe, Sri Lanka and Nepal.In these countries,...
have designed DIY wind turbines that can be easily built by communities in developing nations and are supplying concrete documents on how to do so.
Open source
To assist people in the developing countries, and hobbyists alike, several projects have been open-sourced (e.g. the Jua Kali wind turbine, Hugh Piggot's wind turbine, ForceField Wind Turbine, Chispito Wind Generator., The Zoetrope Vertical-Axis Wind Turbine)Footnotes
^http://Wind-Turbine-24v.com Website With Information on Building Small Wind TurbinesExternal links
- - Home wind generator resource site
- A Dutch government test of 10 wind turbines with English summary here and here
- Challenges of Introducing Reliable Small Wind Turbines
- Small wind turbines (Environmental and Energy Study InstituteEnvironmental and Energy Study InstituteThe Environmental and Energy Study Institute was established by members of the United States Congress who were concerned with environmental and energy problems...
). - Fact sheet by American Wind Energy AssociationAmerican Wind Energy AssociationFormed in 1974, the American Wind Energy Association is a Washington, D.C.-based national trade association representing wind power project developers, equipment suppliers, service providers, parts manufacturers, utilities, researchers, and others involved in the wind industry.With over 2,500...
(AWEA)