After several months testing. Hummer grid-tied inverter has acquired the CE certificate.
The CE certificate number is LC090109-60-CE and LC090109-59-CE.
From:wind turbine manufacturer
2009年1月17日星期六
2009年1月5日星期一
Wind and solar energy utilization and development
Wind turbine and solar energy utilization and development have been three thousand years of history, is an old and the young science, and practical and living close to science, renewable and able to protect the environment science, and now sustainable The development of science, a multi-year investment to benefit from the project. Among the many new areas of energy, wind power and solar energy development and utilization of the first to be affected by giving priority to the development of present-day international is a major hot spots, as photovoltaic and wind power use, not exploitation, do not have transportation, do not have to discharge waste, the environment has not Pollution technology, to protect our planet for the benefit of future generations of long-term project.wind turbine wind generators manufacturer
Wind power and solar power generation from production to deal with the whole process of recovery do not have any pollution, it can increase the supply of electricity and will reduce environmental pollution caused by fuel, so as to protect the Earth's ecological environment is a real green Energy. In 2000, for example, in China's total wind power for the 7.01GW, in place of thermal power can save 278,800 tons of standard coal, reducing SO2 emissions MSO2 to 5668.5 tons, reducing CO2 emissions MCO2 to 718,653 tons and reduce NOX emissions to MNOX 8986 tons, to reduce airborne dust emission MTSP to 251 tons, 1,280,000,000 tons of water-saving. But also because of its reduced air pollution brought about by the indirect benefits are even more enormous.
from:http://www.allwindenergy.com/hummer/post/wind-and-solar-enenrgy.htm
Wind power and solar power generation from production to deal with the whole process of recovery do not have any pollution, it can increase the supply of electricity and will reduce environmental pollution caused by fuel, so as to protect the Earth's ecological environment is a real green Energy. In 2000, for example, in China's total wind power for the 7.01GW, in place of thermal power can save 278,800 tons of standard coal, reducing SO2 emissions MSO2 to 5668.5 tons, reducing CO2 emissions MCO2 to 718,653 tons and reduce NOX emissions to MNOX 8986 tons, to reduce airborne dust emission MTSP to 251 tons, 1,280,000,000 tons of water-saving. But also because of its reduced air pollution brought about by the indirect benefits are even more enormous.
from:http://www.allwindenergy.com/hummer/post/wind-and-solar-enenrgy.htm
2008年11月17日星期一
Why small hummingbird fan resistant to strong winds
Hummingbird wind power generators, light weight, small size, the tail wind turbines under a special light and Weiduo small. 300-watt conventional wind turbine end of a long rod, Weiduo large (as big motors, heavy), wind generators and Wei Duo Mei-under total weight of almost 10 kilograms, while the hummingbird 500-watt wind turbine tail-under Weiduo + Only the weight of 1.7 kg. Do not light a small, non-use of building materials in general, the bar is the end of high-strength side manganese steel pipes, stainless steel is Weiduo.
Small fan using anti-wind-Orio, its tail hummingbird fan in particular small light, wind, Orio is very sensitive and reliable. Wind is not more than 9, the work of hummingbird fans are stable and reliable.
Special Tip: If a typhoon or strong winds forecast over 10 and must end bolt down or tipped over to fans. Because more than 10 highly destructive winds, even if the full fan Orio, 12 are also likely to wind round the wind has been growing too fast, dangerous, even if the round but the wind speed, air Pole may be blown high winds, causing damage and danger. That the small fan to the anti-12 wind view is irresponsible and dangerous.
Small fan using anti-wind-Orio, its tail hummingbird fan in particular small light, wind, Orio is very sensitive and reliable. Wind is not more than 9, the work of hummingbird fans are stable and reliable.
Special Tip: If a typhoon or strong winds forecast over 10 and must end bolt down or tipped over to fans. Because more than 10 highly destructive winds, even if the full fan Orio, 12 are also likely to wind round the wind has been growing too fast, dangerous, even if the round but the wind speed, air Pole may be blown high winds, causing damage and danger. That the small fan to the anti-12 wind view is irresponsible and dangerous.
2008年11月7日星期五
Endless ocean of endless energy - the development of ocean wave energy
From the 1970s oil crisis began, the beginning of attention to the use of local resources and find appropriate low-cost energy. The ocean is the cradle of human birth, 75% of the Earth's oceans are an area of human resources to be obtained from the sea has become an inevitable trend. Following the tidal wave is the generation after generation of the fastest growing forms of marine energy, so far, the world has been Japan, the United Kingdom, Ireland, Norway, Spain, Sweden, Denmark, India, the United States and other countries have been established on the sea waves power generation Device. 100 scientists from various countries over the years made more than 300 kinds of ideas invented a wide range of power generation equipment, power generation, but the prevalence of small, poor quality of power generation, single-kilowatt capacity in the level below, and other defects. Wave power generation technology and thus have not yet reached the level of universal application.
Wave energy is a renewable energy in the most volatile energy, the wave can not produce on a regular basis, with energy and strong, but slower and the changes in the characteristics of the cycle. The current wave-related power generation technology is inadequate, to take the low efficiency, can be converted to the secondary instability, as well as the marine environment of poor adaptability.
Is to introduce the relevant ocean wave energy development and utilization of the two technologies related to the above-mentioned wave power generation technology with the inadequacies of the substantive breakthrough.
Fluctuations in the exchange booster pump to installations
I hope this device to address the shortcomings of existing technology with a view to achieving efficient and can be adopted into a stable direct application of secondary energy. Fluctuations in the exchange booster pump to installations, including the 2 parts floating in the sea for the construction of a receiver and transducer function of the devices, including devices for the high-pressure chamber set the float, the Pistons room, and Pistons room and through the float through the center located along the Sea to pump in the tube. Pistons room on the crossing to open, and even by the high-pressure airway to float high-pressure gas-open side of the room, set in the high-pressure chamber side of the opening set only to return one-way valve piston in the room at the top of the channel is also on both sides of the mouth There are open dish by a small valve controlling the air intake. Another part of the Pistons and the indoor-Pistons even set up to promote the piston rod, the lower end of the piston rod forward even set up a resistance barrier over the plate.
It is worth noting that some of the 2: 1 float above the piston and rod to promote non-rigid connection of the combination of the two, both to ensure that the turbulence in the marine environment and to achieve relative motion with each other in reaction force to maintain vertical; Second, The above-mentioned pressurized gas chamber at the bottom of the sea level should be higher than that of the Pistons-diameter should be greater than the diameter of piston rod forward.
Fluctuations in the booster Oil Painting-Oil Painting Reproduction-Person Oil Painting-China Oil painting-Art Gallery-Famous Oil painting-Seascape oil paintings pump to installations for the work of the course is that float by waves up to the role of lead pipes pump up campaign, and the piston-pump relative to the tube is relatively fixed points, the Pistons at this time of the pressurized chamber room ( Pistons isolation from the body into the upper chamber) of the volume increase, the disc-valve open, gas was inhaled; when the waves could disappear by the float gravity to the role of a certain speed goes down, so that the pressurized chamber Smaller size, gas pressure, the disc-valve closed, only to return one-way valve to open, high-pressure gas flowing through the catheter into the gas-float high indoor air in order to achieve the waves will be transformed into direct access to the To the second.
Pistons body from the sea by a high proportion of the decision itself, it is the same set of values, and because of a deep-sea waves in the sea level by the impact could be negligible. When it float by the waves to the role, can only advance the piston rod along with the occurrence of the relative role of the center line, pipe and pump piston rod to promote mutual restraint is the use of this method to ensure instability in both the marine environment under Relative motion, reaction force to maintain the vertical direction, the highest conversion efficiency.
In other words Piston fluctuations devices
In other words Piston volatile devices, including some of the 3. First, the sea used to build a receiving transducer and the high dam. Second, the bottom of the reservoir set up to take the system unit, which includes a group of miles into the piston and the cylinder containing the Pistons, Pistons to the top of its body through the pressurized tube at the same time floating on a sea-based units of float Pistons in the pressurized tube and pipe, the pipe in the pressurized in the back with only a single valve, in-Pistons on a one-way valve with pressurized water. Third, the Pistons set up a body at the bottom even more resistance to baffle.
In other words Piston fluctuations in the device can process the work is that the cylinder piston movement, compared with the piston-cylinder piston is a relatively fixed points in the wave role can be, and the pressurized sea water into the reservoir in high energy in order to achieve Conversion.
In other words Piston fluctuations devices should be noted that under the waters of the piston within the cylinder with intron-piston between the length of the home by the sea should be greater than the maximum wave height.
Above the sea to build the high dam and into one of the main structure, which is a high degree of design decisions require a high degree of head, it can be secondary to the application of a fixed-head of a high degree of stability in energy. In the role of the wave energy, and the pressurized sea water into the reservoir of high living, to achieve the purpose of energy conversion.
Float on the surface of the water is the carrier of the device, it is taken to the main body of its geometry, but the funnel-shaped cone, which determines the direction of the wave of its non-selective, all-acquisition wave energy. By the waves, float upward movement, will force the cylinder piston upward movement, as opposed to static float at the Sham-Pistons have a relative displacement, wave energy is in the process of acting, that is to take the course. When the waves will disappear, because of their high quality and the quality of the reservoir by Earth's gravity, to a certain speed of sinking, the momentum completely in the role of contrast-piston fixed at the same time, so that the piston inside the water pressure , To the high pressure reservoir, absorption and float momentum into a high reservoir of potential energy in order to achieve a high mining can and must be translated into a high degree of stability in the potential energy. As the piston body weight determines the distance it from the sea is the same set of values, and because of its deep water at the sea surface by the impact of smaller waves, so as to the role of float by the waves, along the only two in the The relative movement of the axis took place, piston and piston-cylinder with each other constraints. Using this method to ensure instability in both the marine environment, to achieve relative motion, in the opposite direction, maintaining the vertical force, the maximum conversion efficiency.
Fluctuations in the booster pump to installations and fluctuations in exchange for piston devices are structural simple, easy to implement and adapt to a variety of environmental waters, and high energy conversion efficiency, high-quality advantages.
Fluctuations in the booster pump to installations and fluctuations in exchange for piston devices, the disorder of the wave energy can be converted to a direct use of the stability of secondary energy. These two technologies can be directly used for power generation, the establishment of marine plants, used in desalination, hydrogen production and exploitation of the manganese nodules.
Wave energy is a renewable energy in the most volatile energy, the wave can not produce on a regular basis, with energy and strong, but slower and the changes in the characteristics of the cycle. The current wave-related power generation technology is inadequate, to take the low efficiency, can be converted to the secondary instability, as well as the marine environment of poor adaptability.
Is to introduce the relevant ocean wave energy development and utilization of the two technologies related to the above-mentioned wave power generation technology with the inadequacies of the substantive breakthrough.
Fluctuations in the exchange booster pump to installations
I hope this device to address the shortcomings of existing technology with a view to achieving efficient and can be adopted into a stable direct application of secondary energy. Fluctuations in the exchange booster pump to installations, including the 2 parts floating in the sea for the construction of a receiver and transducer function of the devices, including devices for the high-pressure chamber set the float, the Pistons room, and Pistons room and through the float through the center located along the Sea to pump in the tube. Pistons room on the crossing to open, and even by the high-pressure airway to float high-pressure gas-open side of the room, set in the high-pressure chamber side of the opening set only to return one-way valve piston in the room at the top of the channel is also on both sides of the mouth There are open dish by a small valve controlling the air intake. Another part of the Pistons and the indoor-Pistons even set up to promote the piston rod, the lower end of the piston rod forward even set up a resistance barrier over the plate.
It is worth noting that some of the 2: 1 float above the piston and rod to promote non-rigid connection of the combination of the two, both to ensure that the turbulence in the marine environment and to achieve relative motion with each other in reaction force to maintain vertical; Second, The above-mentioned pressurized gas chamber at the bottom of the sea level should be higher than that of the Pistons-diameter should be greater than the diameter of piston rod forward.
Fluctuations in the booster Oil Painting-Oil Painting Reproduction-Person Oil Painting-China Oil painting-Art Gallery-Famous Oil painting-Seascape oil paintings pump to installations for the work of the course is that float by waves up to the role of lead pipes pump up campaign, and the piston-pump relative to the tube is relatively fixed points, the Pistons at this time of the pressurized chamber room ( Pistons isolation from the body into the upper chamber) of the volume increase, the disc-valve open, gas was inhaled; when the waves could disappear by the float gravity to the role of a certain speed goes down, so that the pressurized chamber Smaller size, gas pressure, the disc-valve closed, only to return one-way valve to open, high-pressure gas flowing through the catheter into the gas-float high indoor air in order to achieve the waves will be transformed into direct access to the To the second.
Pistons body from the sea by a high proportion of the decision itself, it is the same set of values, and because of a deep-sea waves in the sea level by the impact could be negligible. When it float by the waves to the role, can only advance the piston rod along with the occurrence of the relative role of the center line, pipe and pump piston rod to promote mutual restraint is the use of this method to ensure instability in both the marine environment under Relative motion, reaction force to maintain the vertical direction, the highest conversion efficiency.
In other words Piston fluctuations devices
In other words Piston volatile devices, including some of the 3. First, the sea used to build a receiving transducer and the high dam. Second, the bottom of the reservoir set up to take the system unit, which includes a group of miles into the piston and the cylinder containing the Pistons, Pistons to the top of its body through the pressurized tube at the same time floating on a sea-based units of float Pistons in the pressurized tube and pipe, the pipe in the pressurized in the back with only a single valve, in-Pistons on a one-way valve with pressurized water. Third, the Pistons set up a body at the bottom even more resistance to baffle.
In other words Piston fluctuations in the device can process the work is that the cylinder piston movement, compared with the piston-cylinder piston is a relatively fixed points in the wave role can be, and the pressurized sea water into the reservoir in high energy in order to achieve Conversion.
In other words Piston fluctuations devices should be noted that under the waters of the piston within the cylinder with intron-piston between the length of the home by the sea should be greater than the maximum wave height.
Above the sea to build the high dam and into one of the main structure, which is a high degree of design decisions require a high degree of head, it can be secondary to the application of a fixed-head of a high degree of stability in energy. In the role of the wave energy, and the pressurized sea water into the reservoir of high living, to achieve the purpose of energy conversion.
Float on the surface of the water is the carrier of the device, it is taken to the main body of its geometry, but the funnel-shaped cone, which determines the direction of the wave of its non-selective, all-acquisition wave energy. By the waves, float upward movement, will force the cylinder piston upward movement, as opposed to static float at the Sham-Pistons have a relative displacement, wave energy is in the process of acting, that is to take the course. When the waves will disappear, because of their high quality and the quality of the reservoir by Earth's gravity, to a certain speed of sinking, the momentum completely in the role of contrast-piston fixed at the same time, so that the piston inside the water pressure , To the high pressure reservoir, absorption and float momentum into a high reservoir of potential energy in order to achieve a high mining can and must be translated into a high degree of stability in the potential energy. As the piston body weight determines the distance it from the sea is the same set of values, and because of its deep water at the sea surface by the impact of smaller waves, so as to the role of float by the waves, along the only two in the The relative movement of the axis took place, piston and piston-cylinder with each other constraints. Using this method to ensure instability in both the marine environment, to achieve relative motion, in the opposite direction, maintaining the vertical force, the maximum conversion efficiency.
Fluctuations in the booster pump to installations and fluctuations in exchange for piston devices are structural simple, easy to implement and adapt to a variety of environmental waters, and high energy conversion efficiency, high-quality advantages.
Fluctuations in the booster pump to installations and fluctuations in exchange for piston devices, the disorder of the wave energy can be converted to a direct use of the stability of secondary energy. These two technologies can be directly used for power generation, the establishment of marine plants, used in desalination, hydrogen production and exploitation of the manganese nodules.
2008年10月8日星期三
wind power industry is ushered in the golden age
From the convening of Xiangtan in Hunan, China's wind power industry in mechanical and industrial seminars will be understanding, Hunan Yu Jian of the National number one wind power industry cluster. At the meeting, the Standing Committee of the Hunan Provincial Party Committee, vice-governor Xu Xianping predicted in the near future, a national leading wind power equipment industry cluster in Hunan into the sky.
It is understood that from the oil painting ,beginning of 2005, Hunan, began plotting the development of wind power industry, has taken shape in Zhuzhou Southern Co., Ltd., Zhuzhou and Xiangtan Electric Group to lead the two major wind power a small industrial clusters. In September 2005, the National Wind Power Engineering Research Center to do in the locomotive and cars in the world famous South Zhuzhou Electric Co., Ltd. set up. In August 2006, Zhuzhou Southern car and Urumqi in Xinjiang Gold Wind Science and Technology Corporation signed more than 200 wind electric power generation contract.
At present, is located in Zhuzhou (national) high-tech development zone of Zhuzhou wind power equipment manufacturing base is in the planning and construction. The Chinese electrical products enjoy a reputation as the cradle of the Gordon Group of electricity as early as the early 1990s on research and development of the first in China to 200 kilowatt wind turbine, one after another and then developed a 300 kilowatt, 1300 kilowatts, 2200 kilowatts of wind and other Generators. To seize the enormous potential of wind power market, recently, Japan join hands in Xiangtan Electric Group Co., Ltd. production of the original Philip, the joint venture was set up wind power Lake Nan Xiang Co., Ltd., with an annual output of RMB may megawatt-class wind power generating units of 300 to achieve Sales of more than 3.0 billion. January 14, covers an area of 250 acres of the total installed capacity of wind power Xiang factory in Xiangtan (Germany) industrial park foundation.
In addition to the two fat, such as Hunan Zhuzhou Times Group to create high-quality companies are also part of the redoubling its efforts to build wind power equipment production base. As vice-governor Xu said, a large-scale wind power industry cluster, in Hunan Province is taking shape at the beginning. China's wind power industry development in the future is already here referred to the golden age of wind power, more people think of is this: under the blue sky and white clouds, white frame of a windmill, rotating the long leaf fan ... ....
China's hydropower consultants of the Group of Hospitals and South Africa by wind power experts say China's wind energy resources are abundant. According to the more than 900 weather stations nationwide observation data estimated that the land-based wind energy resources in China total reserves of approximately 3,226,000,000 kilowatts, of which wind energy can be developed reserves of 253,000,000 kilowatt, and the wind on the sea reserves are 750,000,000 kilowatts, for a total of 1,000,000,000 kilowatts, which is 10 meters high degree of calculation, if the 50 meters, according to the terms, it would also be doubled.
He said that China's wind generator industry, with Europe and the United States, in particular, there are comparable between the Asian countries. According to the latest data, Europe is the world's major wind power market, as of the end of 2005, the installed capacity of 410,000,000 kilowatts, accounting for the world's total wind power installed capacity of 69%. India's installed capacity of wind power is also the country's total power installed capacity of 3% of the total. However, the deduction of time, the future of China's wind power industry will have grown by leaps and bounds.
According to the State Development and Reform Commission plans, by 2020 China's total wind power installed capacity will increase to 30,000,000 kilowatts. China's hydropower consultants of the Group of Hospitals and South Africa experts believe that the current momentum of the wind power plant construction, will go a long way ahead. He estimated that during the 11th Five-Year Plan, the national total installed capacity of wind power is likely to 20,000,000 kilowatts, wind power equipment market will reach 1,300 billion yuan.
It is understood that from the oil painting ,beginning of 2005, Hunan, began plotting the development of wind power industry, has taken shape in Zhuzhou Southern Co., Ltd., Zhuzhou and Xiangtan Electric Group to lead the two major wind power a small industrial clusters. In September 2005, the National Wind Power Engineering Research Center to do in the locomotive and cars in the world famous South Zhuzhou Electric Co., Ltd. set up. In August 2006, Zhuzhou Southern car and Urumqi in Xinjiang Gold Wind Science and Technology Corporation signed more than 200 wind electric power generation contract.
At present, is located in Zhuzhou (national) high-tech development zone of Zhuzhou wind power equipment manufacturing base is in the planning and construction. The Chinese electrical products enjoy a reputation as the cradle of the Gordon Group of electricity as early as the early 1990s on research and development of the first in China to 200 kilowatt wind turbine, one after another and then developed a 300 kilowatt, 1300 kilowatts, 2200 kilowatts of wind and other Generators. To seize the enormous potential of wind power market, recently, Japan join hands in Xiangtan Electric Group Co., Ltd. production of the original Philip, the joint venture was set up wind power Lake Nan Xiang Co., Ltd., with an annual output of RMB may megawatt-class wind power generating units of 300 to achieve Sales of more than 3.0 billion. January 14, covers an area of 250 acres of the total installed capacity of wind power Xiang factory in Xiangtan (Germany) industrial park foundation.
In addition to the two fat, such as Hunan Zhuzhou Times Group to create high-quality companies are also part of the redoubling its efforts to build wind power equipment production base. As vice-governor Xu said, a large-scale wind power industry cluster, in Hunan Province is taking shape at the beginning. China's wind power industry development in the future is already here referred to the golden age of wind power, more people think of is this: under the blue sky and white clouds, white frame of a windmill, rotating the long leaf fan ... ....
China's hydropower consultants of the Group of Hospitals and South Africa by wind power experts say China's wind energy resources are abundant. According to the more than 900 weather stations nationwide observation data estimated that the land-based wind energy resources in China total reserves of approximately 3,226,000,000 kilowatts, of which wind energy can be developed reserves of 253,000,000 kilowatt, and the wind on the sea reserves are 750,000,000 kilowatts, for a total of 1,000,000,000 kilowatts, which is 10 meters high degree of calculation, if the 50 meters, according to the terms, it would also be doubled.
He said that China's wind generator industry, with Europe and the United States, in particular, there are comparable between the Asian countries. According to the latest data, Europe is the world's major wind power market, as of the end of 2005, the installed capacity of 410,000,000 kilowatts, accounting for the world's total wind power installed capacity of 69%. India's installed capacity of wind power is also the country's total power installed capacity of 3% of the total. However, the deduction of time, the future of China's wind power industry will have grown by leaps and bounds.
According to the State Development and Reform Commission plans, by 2020 China's total wind power installed capacity will increase to 30,000,000 kilowatts. China's hydropower consultants of the Group of Hospitals and South Africa experts believe that the current momentum of the wind power plant construction, will go a long way ahead. He estimated that during the 11th Five-Year Plan, the national total installed capacity of wind power is likely to 20,000,000 kilowatts, wind power equipment market will reach 1,300 billion yuan.
2008年9月5日星期五
Wind energy technology in china
Wind turbines produce electricity by using the natural power of the wind to drive a generator. The wind is a clean and sustainable fuel source, it does not create pollution and it will never run out. Wind energy technology is developing fast, turbines are becoming cheaper and more powerful, bringing the cost of renewably-generated electricity down. Europe is at the hub of this high-tech industry.
The need for clean energy
Conventional methods of generating electricity burn fuel to provide the energy to drive a wind generator, usually by using the heat to provide steam to drive a turbine. These technologies may use fossil fuels, - coal, oil or gas - or nuclear fuel. Using fossil fuels creates pollution, such as oxides of sulphur and nitrogen which contribute to acid rain, and carbon dioxide which contributes to global climate change.
Although conventional sources of power dominate the energy needs of European countries, wind energy is growing rapidly. Renewable energy sources currently provide nearly 5.4% of the European Union's primary energy needs1 and have the potential to provide much more.
How wind turbines work
Almost all wind turbines producing electricity for the national grid consist of rotor blades which rotate around a horizontal hub. The hub is connected to a gearbox and generator, which are located inside the nacelle. The nacelle houses the electrical components and is mounted at the top of the tower. This type of turbine is referred to as a 'horizontal axis' machine.
Rotor diameters range up to 80 metres, smaller machines (around 30 meters) are typical in developing countries
Wind turbines can have three, two or just one rotor blades. Most have three.
Blades are made of fibreglass-reinforced polyester or wood-epoxy.
The blades rotate at 10-30 revolutions per minute at constant speed, although an increasing number of machines operate at a variable speed.
Power is controlled automatically as wind speed varies and machines are stopped at very high wind speeds to protect them from damage.
Most have gearboxes although there are increasing numbers with direct drives.
The yaw mechanism turns the turbine so that it faces the wind. Sensors are used to monitor wind direction and the tower head is turned to line up with the wind.
Towers are mostly cylindrical and made of steel, generally painted light grey. Lattice towers are used in some locations. Towers range from 25 to 75 meters in height.
Commercial turbines range in capacity from a few hundred kilowatts to over 2 megawatts. The crucial parameter is the diameter of the rotor blades - the longer the blades, the larger the area 'swept' by the rotor and the greater the energy output. At present the average size of new machines being installed is now super megawatt, 1.3-1.85MW, and there are larger machines on the market. The trend is towards moving to these larger machines as they can produce electricity at a lower price.
There are many different turbine designs, with plenty of scope for innovation and technological development. The dominant wind turbine design is the up-wind, three bladed, stall controlled, constant speed machine. The next most common design is similar, but is pitch controlled. Gearless and variable speed machines follow, again with three blades. A smaller number of turbines have 2 blades, or use other concepts, such as a vertical axis.
Most turbines are upwind of the tower - they face into the wind with the nacelle and tower behind. However, there are also downwind designs, where the wind passes the tower before reaching the blades.
Stall and pitch control
There are two main methods of controlling the power output from the rotor blades. The angle of the rotor blades can be actively adjusted by the machine control system. This is known as pitch control. This system has built-in braking, as the blades become stationary when they are fully 'feathered'.
The other method is known as stall control. This is sometimes known as passive control, since it is the inherent aerodynamic properties of the blade which determine power output; there are no moving parts to adjust. The twist and thickness of the rotor blade vary along its length in such a way that turbulence occurs behind the blade whenever the wind speed becomes too high. This turbulence means that less of the energy in the air is transfered, minimising power output at higher speeds. Stall control machines also have brakes on the blade tips to bring the rotor to a standstill, if the turbine needs to be stopped for any reason.
Most wind turbines start operating at a speed of 4-5 metres per second and reach maximum power at about 15 m/s.
Factors affecting performance
Most important is the windiness of the site. The power available from the wind is a function of the cube of the wind speed. Therefore a doubling of the wind speed gives eight times the power output from the turbine. All other things being equal, a turbine at a site with an average wind speed of 5 meters per second (m/s) will produce nearly twice as much power as a turbine at a location where the wind averages 4 m/s.
Second is the availability of the equipment. This is the capability to operate when the wind is available - an indication of the turbine's reliability. This is typically over 98% for modern machines. Last is turbine arrangement. Turbines in wind farms must be carefully arranged to gain the maximum energy from the wind - this means that they should shelter each other as little as possible from the prevailing wind.
Wind energy production and electricity demand
The wind is an intermittent energy resource - it does not blow all the time - but this does not reduce its value as a source of power. The variable output from wind energy poses no special difficulty for power system operation. Electricity demand is constantly fluctuating, and supply and demand have to be matched on a minute to minute basis, 24 hours of the day, every day of the year. The fluctuation caused by the introduction of wind to the system is not discernible above these normal fluctuations, and will not be until electricity generated from wind turbines reaches approximately 20% of the total system supply.
Wind energy effectively 'shaves off' some of the demand which has to be met by conventional generating plant. This is often described as having a 'negative load' effect on the electricity network.
Wind energy coincides well with period of peak electricity demand. Demand often peaks on cold windy winter days - just when wind turbines are at their most productive. Figure 2 illustrates the concept of negative load. It shows the electricity demand over a seven day period in February 1996 in England and Wales, at a time when demand was at one of the highest levels that year. The wind farm output data is the actual output of four wind farms, scaled up to show the effect of 10,000 megawatts of installed capacity. This would meet 10% of England and Wales' annual electricity demand.
Figure 2 The negative load effect: how wind energy reduces the need for conventional power.
(Source Econnect Ltd, UK, using data from the National Grid Company and wind farms.)
Figure 3 shows how well wind energy is matched to demand around the year. Electricity demand is higher in the winter, and winter months are also the windiest.
Figure 3 Yearly wind energy output and seasonal electricity demand.
(Source Econnect Ltd, UK, using data from the National Grid Company and wind farms.)
Capacity credit
Another way of looking at the value of wind energy is to look at its capacity credit. The capacity credit of a certain amount of wind energy can be thought of as the amount of conventional plant which could be 'replaced' by wind power, without making the system less reliable. In reality wind turbines are not installed in order that conventional power stations can close prematurely; building wind farms does help avoid the need to build new thermal or nuclear power plants.
Studies on how wind energy can best be integrated into electricity networks have been carried out in several European countries. Each study concludes that wind energy does have a significant capacity credit. In Denmark a capacity credit of 20 - 25% is used in comparative studies of the economy of different new energy technologies, and the country now gets around 20% of it's electricity from wind energy!
Other benefits of wind power
Apart from generating electricity without causing pollution, wind energy has numerous other advantages.
It is widely distributed - more countries have sizeable wind power potential than have large resources of hydro-power or fossil fuel reserves.
It is ideal for generating electricity at a local level - European wind schemes are typically clusters of around 10 - 40 turbines, providing enough electricity for 4,000 to 16,000 households. Some countries such as Denmark and Germany also have a high proportion of single turbines. The electricity can be fed directly into the distribution network, reducing electricity distribution and transmission losses. By contrast, electricity from larger power stations has to be transmitted on high voltage power lines and travel long distances before it gets to the point of use.
Wind energy is good for island communities - the supply can be connected to diesel or solar systems to provide back-up when the wind is not blowing.
Wind energy is low risk - the relatively small unit size of each individual wind turbine (or wind scheme) also reduces the risk of technical failure or industrial action compared with larger generating units.
Wind energy encourages energy diversity - it is sensible for any nation to have a balanced portfolio of energy technologies, rather than to rely heavily on a small number of energy sources. The energy mix among different European countries varies widely, with some countries more dependent on energy imports than others. The UK and Germany have a relatively diverse mix of fuels, whereas others are more dependent on oil (Spain and Greece), coal (Denmark) and nuclear (France and Belgium). Expanding the use of wind energy will increase energy diversity and improve the security of electricity supply. Energy diversity lessens international political sensitivity concerning fossil fuel reserves, volatility of oil and gas prices and the risks associated with nuclear power.
Wind energy capacity in Europe
Europe is the world leader in wind energy, with more installed capacity than any other region of the world. By the end of 1999 there was over 8,500 megawatts of installed capacity - more than double figures for 1996. This growth trend is expected to continue as wind is the fastest growing energy sector worldwide.
The future of wind energy
Improvements in wind energy technology mean that the trends which have led to the dramatic fall in the cost of wind energy are set to continue.
Countries all over the world are setting targets for wind power. It is estimated that 22,000 megawatts of wind energy capacity, in the form of 40,000 wind turbines will be installed in the next 10 years. This represents an annual market of around 2.4 billion Euros . Europe is the hub of this global business, with six companies supplying over half of the world's turbines global wind energy market. Europe stands to benefit greatly from this move towards sustainability.
Glossary and References
1 unit of electricity = 1 kilowatt hour
1,000 kilowatts = 1 megawatt
1 The Declaration of Madrid: An action plan for renewable energy sources in Europe. CEC, 1994
From:wind turbine
2008年8月9日星期六
Wind energy resources
Wind energy resources is a can of clean renewable energy.
Yunnan majority of Pingba relatively poor areas of wind energy resources, wind energy resource-rich mountain. Meteorological stations throughout the province effective density 44.2-167.5 watts / square meter, effective use of a few hours 300-6500.
Wind energy resources in the distribution of the East West more than less, in most areas east of Ailaoshan effective wind energy density at 75 watts / sq m and above, the effective use of a few hours in 2000. Mountain effective wind energy density of up to 160 watts / sq m and above, the effective use of the number of hours up to 6000 hours, the most abundant wind energy close to the area level.
Ailaoshan most areas west of the effective wind energy density of 60 watts / square metres below the effective use of a few hours following the 1500-2000, the average wind speed in most parts of 3 m / s following, in addition to individual mountain, the wind had Development of value.
Wind energy resources distribution of the year season is the dry season, small rainy season. The dry season, the wind speed, wind energy density effectively, in more than 100-150 watts / sq m and above, the number of hours and more effective use of 500 hours or more. On the negative rate of the rainy season is generally in the 2 m / sec below, there is no development value.
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