Dissertation for Master's Degree in Power Electricity
Chapter One
General information about wind energy and wind turbines
Foreword
Energy supply and demand in the world to It has become one of the most important issues of the day, so that the world will be seriously involved in it until the end of the 20th century and even after that. Fossil energies such as oil, gas and coal are facing a new big challenge. It has caused developed industrial countries to pay attention to the use of other new energies as seriously as possible. Using the energy of the sun, wind and waves, geothermal, hydrogen, biomass and so on. which is called new energy, requires many studies and researches that must be done before use. Now, extensive studies in this field have been started in developed countries for years.
Introduction
The extent of human need for energy sources has always been one of the important basic issues in human life, and trying to achieve an inexhaustible source of energy has been one of the long-standing aspirations of man.
The patterns carved on the walls of the caves show that early humans were able to recognize and use muscle power as a source of mechanical energy. But since this force is very limited and weak, man always searched in his imagination for an inexhaustible force that is always available at any time and place. This topic can be well understood in various stories that were created by the imagination of the first human mind. Little by little, with the progress of human civilization, wood and then coal, oil and gas entered the energy market. However, due to the increasing need for energy and the limitation of fossil resources, on the one hand, the increase in environmental pollution caused by burning these resources, on the other hand, the use of renewable energy is becoming more and more important and widespread. Wind energy is one of the main types of renewable energy that has attracted the attention of mankind for a long time, so that he has always thought about the use of this energy in industry. Mankind has used wind energy to propel boats and sailing ships and windmills. In the current situation, considering the mentioned cases and the economic justification of wind compared to other sources of new energy, dealing with wind energy seems vital and necessary. In our country, Iran, there are suitable capabilities and potentials for installing and operating wind turbines. Considering its justification and the research, studies and investment that has been made in this field, the development and application of this technology has given a clear perspective to the country's energy policy makers in this field. This energy was used to propel ships and windmills. Over the years, it has been proven that wind energy can be converted into mechanical energy and used. Historical sources show that the construction of mills in Iran, Iraq, Egypt and China is ancient and in these civilizations windmills were used to crush seeds and pump water.
Ayed, in the 17th century BC, the Babylonian king Murabi had presented a plan to irrigate the fertile plain of Mesopotamia with wind energy. The mills that were built at that time were vertical axis type machines and are similar to the ones whose traces can be seen today in Khaf and Taybad areas of Iran. Iranians were the first to use windmills with vertical axis to grind grains in about 200 years before Christ. For example, in old books they wrote: Sistan is a land of wind and sand, and it is the city where they say the wind turns the mills and draws water from the well. and water the gardens, and there is no city in the whole world that benefits more from the wind than there.And they also wrote that strong winds blow constantly in Sistan and for this reason they built windmills to grind wheat there. Among other provinces with a history of using wind energy, we can mention Kerman, Isfahan, and Yazd. In these places, in ancient times, special channels were used to direct the wind to cool the houses. After Iran, Arab and European countries discovered the power of wind to convert energy. In the third century BC, an Egyptian researcher in the field He was researching the power of compressed air, he designed a four-bladed windmill with a horizontal axis, which used its compressed air to play an organ. According to the available evidence, it can be claimed that the birthplace of vertical axis wind machines was the eastern Mediterranean area and China. In the middle century, windmills became popular in Italy, France, Spain and Portugal, and a little later they were used in Great Britain, Holland and Germany. Some historians have stated that the arrival of these mills in Europe should be considered as participants in natural forests returning from the Middle East. Windmills that were built in Europe. They were type of windmills with a horizontal axis and four blades, which were used to flour beans and wheat. Dutch people used windmills since 1350 AD to dry coastal low lands, as well as extract oil from seeds, cut wood, and prepare color powder for dyeing. What made the Netherlands one of the richest and most industrialized people in Europe in the 17th century was the shipbuilding industry and the construction of windmills in that country. Concrete wind turbines consisting of multiple blades became common later. At the beginning of the 20th century, the first fast and modern wind turbines were built. Today, the most active countries in this field are Germany, Spain, Denmark, India, and America. rtl;"> When the sun's radiation reaches the uneven surfaces of the earth unevenly, it causes changes in temperature and pressure, and as a result of these changes, wind occurs. Also, the earth's atmosphere transfers heat from the tropical regions to the polar regions due to the movement of the earth's position, which also causes the creation of wind. Ocean currents also act in a similar way and are responsible for 30% of the total heat transfer in the world. On a global scale, these atmospheric currents are a strong factor for heat transfer. The earth's cycle can also create double energy in establishing semi-permanent patterns of planetary currents in the atmosphere. Then, as mentioned, wind is one of the different forms of solar heat energy, which has a semi-continuous pattern, changes in wind speed are hourly, daily, and seasonal, and are affected by the weather and the topography of the earth's surface. Most of the sources of wind energy are located in mountainous areas.