WTT-W2-Slides.pdf - Energy in Wind Assist Prof Mahmut Sami...

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Energy in Wind to accompany Wind Turbine Technology , by A Hemami (2012) Chapter 2 Assist. Prof. Mahmut Sami BÜKER
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Energy and Power Energy is the potential to do work different forms of energy Work implies mechanical or other type of work Mechanical work is more tangible a battery does not directly do mechanical work, however, it can run a motor; thus, a battery has the potential to perform work. It has electrical energy Heating water is another form of work , although it is not mechanical ; but, it can be converted to mechanical work (consider a steam turbine) In this sense, heat (that can raise the temperature of a material) is a form of energy. It is “thermal energy.” Examples of other types of energy are chemical energy, solar energy, wind energy, and nuclear energy
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Now, suppose that a machine or device has energy. How much energy does it have? how much work can it do? if a machine can do a certain amount of work, how long does it take to do that work? Is it capable of doing that work in 1 min or in 25 min, for example? Power is the amount of work done in 1 sec by a device that can do work. This is the measure of strength of energy sources. It can also be used to compare two or more devices. For instance, a smaller motor has less power than a larger motor; that is, it can do less work than the larger motor in the same amount of time. Energy and Power
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Energy and Power Any moving object has energy. This type of energy is called kinetic energy. For example, a car, a bicycle, or a ball, when moving, all have kinetic energy. The same is true for moving air, that is, the wind. The amount of energy of a moving object depends on two factors, its mass and its speed. Therefore, the energy of a moving object is Energy= ½ (mass)*(speed) 2 This equation implies that, for example, if mass is doubled (that is, if you have two objects the mass of one of which is two times the mass of the other, both having the same speed), the energy doubles. Nevertheless, if the speed is doubled (if you have two objects of the same mass, but one has a speed two times that of the other), then the energy is four times more. (1)
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Energy in a moving fluid Energy in a moving fluid (a gas or a liquid) can be found in the same way as described for a solid body There are two differences, however, that must be taken into account. The first difference is that for a fluid in motion, we define the moving mass by its volume. This is so because there is no solid object with a definite mass to be considered. The second difference is that for a moving fluid, the whole volume moves. We first consider a simpler case where the fluid is confined in a boundary. This is the case of flow in a pipe, for example.
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  • Spring '11
  • O.Uzol
  • Energy, Wind speed

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