Wind energy. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Wind energy. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Alternative energy sources

Comments on the article

Wind turbines (WPPs) have now reached the level of commercial maturity and in places with favorable wind speeds can compete with traditional sources of electricity. Of the various devices that convert wind energy into mechanical work, in the vast majority of cases, bladed machines with a horizontal shaft installed in the direction of the wind are used. Devices with a vertical shaft are much less commonly used.

The kinetic energy carried by the wind flow per unit time through an area of 1 m2 (specific flow power) is proportional to the cube of the wind speed. Therefore, the installation of wind turbines is expedient only in places where the average annual wind speeds are high enough.

A wind wheel placed in a free air flow can at best theoretically convert into power on its shaft 16/27=0,59 (Betz criterion) the power of the air flow passing through the cross-sectional area swept by the wind wheel. This coefficient can be called the theoretical efficiency of an ideal wind wheel. In reality, the efficiency is lower and reaches about 0,45 for the best wind wheels. This means, for example, that a wind wheel with a blade length of 10 m at a wind speed of 10 m/s can have a shaft power of 85 kW at best.

The most widespread of the installations connected to the network today are wind power plants (wind turbines) with a unit capacity of 100 to 500 kW. The specific cost of wind turbines with a capacity of 500 kW is now about 1200 USD/kW and tends to decrease.

Along with this, wind turbines are being created with a significantly larger unit capacity. In 1978, the first experimental wind turbine of the megawatt class with an estimated power of 2 MW was created in the USA. Following this, in 1979-1982. in the United States, 5 wind turbines with a unit capacity of 2,5 MW were built and tested. By that time, the largest wind turbine (Grovian) with a capacity of 3 MW was built in Germany in 1984, but, unfortunately, it worked for only a few hundred hours. WTS-3 and WTS-4 wind turbines, built a little later in Sweden with a capacity of 5 and 4 MW, respectively, were installed in Sweden and the USA and worked for the first 20, and the second for 10 thousand hours.

In Canada, work is underway to create large wind turbines with a vertical shaft (the Darrieus rotor). One such installation with a capacity of 4 MW has been tested since 1987. In total, for 1987-1993. about 25 megawatt-class wind turbines have been built in the world.

The design wind speed for large wind turbines is usually taken at the level of 11-15 m/s. In general, as a rule, the greater the power of the unit, the greater the wind speed it is calculated for. However, due to the variability of the wind speed, most of the time, the wind turbine produces less power. It is believed that if the average annual wind speed in a given place is at least 5-7 m / s, and the equivalent number of hours per year at which the rated power is generated is at least 2000, then such a place is favorable for installing a large wind turbine and even a wind farm.

Autonomous installations of a kilowatt class, designed to supply relatively small consumers, can also be used in areas with lower average annual wind speeds.

Today, in some industrialized countries, the installed capacity of wind turbines reaches significant values. Thus, more than 1,5 million kW of wind turbines have been installed in the USA; in Denmark, wind turbines produce about 3% of the energy consumed by the country; the installed capacity of wind turbines is large in Sweden, the Netherlands, Great Britain and Germany.

As the equipment of wind turbines improves and the volume of their production increases, the cost of wind turbines, and hence the cost of the energy they produce, is reduced. If in 1981 the cost of electricity produced by wind turbines was about 30 US cents per kWh, today it is 6-8 cents. With four large wind farms operating in the US in 1995 alone, with a total capacity of about 200 MW, it is clear that the US Department of Energy's planned reduction in the cost of wind power to 2,5 cents/(kWh) is quite really.

In developing countries, interest in wind turbines is associated mainly with low-power autonomous installations that can be used in villages remote from centralized power supply systems. Such units are already competitive today with diesel engines running on imported fuel. However, in some cases, the variability of the wind speed forces either to install a storage battery in parallel with the wind turbine, or to reserve it with an installation on fossil fuel. Naturally, this increases the cost of the installation and its operation, so the distribution of such installations is still small.

See other articles Section Alternative energy sources.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive

Shortest travel mechanical switches 12.09.2017

Mechanical keyboards are popular with everyone from hardcore gamers to heavy typists. But due to the fact that people often work on laptops, they develop a habit of typing on keyboards with a short stroke. Appropriate switches to create desktop keyboards with this travel were inevitable and they already exist on the market. But progress does not stand still and new, more and more interesting models appear.

Kaihua, the owner of the Kailh brand, has announced that its new model, the Choc PG1232, is the shortest-stroke in the world. Indeed, the stem of these switches travels only 2,4 mm (with a tolerance of +/- 0,5 mm), with only 1,2 mm travel before actuation. Tactile novelties are quite "heavy" - they require a force of 50 grams at the actuation point and 60 grams at the "click" point. This is only slightly less than full-stroke models.

In comparison, the PG1350 has 3mm of travel with an actuation point of around 1,5mm. The developer claims the reliability of PG1232 at 25 million clicks, which is half the usual; moreover, the aforementioned PG1350s have a lifespan of 70 million clicks. These models have compatible keycap mounts.

So far, only the "white" (with a "click") version is available, but if there is sufficient demand for new switches, Kaihua will release other "color" variations of the PG1232, such as "red" (linear) and "brown" (with improved tactile feedback). ).

Other interesting news:

▪ Bloodhounds of mercury

▪ Linear Voltage Regulator LT3021

▪ Airplane comfort and dryness

▪ American Roulette

▪ Memory shirt

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Measuring equipment. Article selection

▪ article by Johann Jakob Engel. Famous aphorisms

▪ What were education and culture like in the early Middle Ages? Detailed answer

▪ article Linear pipeline. Standard instruction on labor protection

▪ article Module of electronic switching of tools. Encyclopedia of radio electronics and electrical engineering

▪ article 10m direct conversion CW-SSB transceiver. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews