- First law of thermodynamics
- Stages for generating electricity
- Wind blades
- The rotor
- List of references
The demand for renewable energy has contributed immensely towards the growth of wind energy industry. Nations such as the United States have shifted away from using fossil fuels. However, the success of wind energy industry depends greatly on wind turbines. A wind turbine is a technological device used in converting energy present in the moving wind into mechanical energy.
Occasionally, the mechanical energy that rotates the shaft is converted by a wind turbine generator into electrical energy (Rivkin 2011, p.1). The generators are usually fixed at the top of the towers in order to maximize the output of wind energy turbines. To enhance their activity, generators are usually joined to the rotors by gears that multiply the speed of the generator.
This paper seeks to describe how wind turbines convert wind energy into electrical energy. This paper also provides broad explanation on how various parts of the turbine work together in enhancing conversion of wind energy into electrical energy.
First law of thermodynamics
According to the first law of thermodynamics, energy cannot undergo destruction or creation. In essence, energy is prone to conversion from one state to another. Thus, energy produced by the turbines ought to have great relation with the energy that was drove into the turbine generators by the blades.
The turbine is made up of various parts that work together. For instance, the connection of the blades of the wind turbine to the shaft, and the shaft to the gearbox of the turbine plays a crucial role in the generation of electricity (Rivkin 2011, p.4).
Stages for generating electricity
The process of generating electricity from wind energy is a bit complex. It involves two stages. In the first stage, it dictates for the conversion of kinetic energy present in the moving wind into mechanical energy that drives the shaft fixed into the wind generator. The crucial elements that play a significant role during this stage are the wind blades.
Therefore, careful designs of the blades aid in maximizing the efficiency of the turbines in electricity generation (Tong 2010, p.20). However, diverse factors affect the amount of mechanical energy produced by the blades. For instance, the shape of blade tips and general profile of the blades determines the amount of mechanical energy produced by the blades.
The second stage of electricity generation from wind energy involves the conversion of trapped mechanical energy into electrical energy via aid of wind generators. This stage also aids in outlining various parameters that assist in determining the conversion efficiency of the generators. For instance, it aids in calculating the efficiency of gearbox, generators, and electric appliances.
Movement of the wind
The wind blows play a significant role in enhancing the movement of the generators; they enhance the spinning of the shaft via rotating the turbine blades. Additionally, the connection of the shaft to the gearbox expounds the output of the turbine.
The gearbox plays a significant role in multiplying the rotational speed of blade shaft to the speed recommended for the generator. On the other hand, the generator plays a significant role in converting kinetic energy into electrical energy.
Wind is the product of the movement of air caused by variation in atmospheric pressure gradients. Occasionally, wind flows from regions experiencing high pressure to regions that have low wind pressure. Its effect is greatly felt when the atmospheric pressure gradient is very large (Tong 2010, p.6).
Most modern wind turbines blades have great relation to the blades used in flights; their blades are tilted in order to maximize wind power output. The kinetic energy of the wind can be calculated by using the formula below
In the above equation, m is the mass of the flowing air, and is the mean speed of the wind over a given period. The differentiation of the moving energy in wind with time leads to production of wind power that is calculated by the formula below
Unfortunately, only a small portion of wind power is turned into electrical power. The movement of the wind across the turbines leads to the creation of wind mass that rotates the blades. The air mass responsible for the rotation of the blades is calculated using the formula below
In which p represents the air density and A the area swept by the rotating blades.
The area swept by the blades plays a significant role in determining the amount of power generated by the turbines. The larger the swept surface area the greater the amount of wind power produced by the wind turbine (Tong 2010, p.10). The area swept by the blades is calculated by the formula below
The rotor is a central device to which the blades are connected. It plays a significant role in directing the energy tapped from the blowing wind by the blades to the shaft. Its spinning leads to the spinning of the shaft which as a result leads to the generation of mechanical energy.
A shaft is a device in wind turbines that aids in conversion of kinetic energy into electrical energy. Its rotation is enhanced by mechanical energy that is converted from kinetic energy of the rotating blades. It is connected to the magnets within the generators. Its spinning plays a crucial role in creation of a magnetic field that leads to the generation of electric voltage within the generator.
Generators play crucial role in production of electricity. However, the functioning of the generators relies greatly on the mechanical energy produced by the shafts and the gearboxes. The rotation of the shaft leads to the spinning of the devices within the generator.
The spinning of the devices within the generators also contribute significantly towards creation of voltage. Some of the devices that make up the generator include slip rings, commutators, armature, and magnets (Rivkin 2012, p.65).
Most wind turbine generators use alternative current. They are made up of a pair of slip rings that are connected to different devices; one is connected to the armature coil and the other one to another armature winding. Slip rings play the role of transferring electric power from stationery devices within the generator to rotating devices.
Slip rings possess some brushes that pave way for the movement of the current from one ring device to another. Additionally, slip rings play a significant role in enhancing the rotation of armature; they help in the determination of the amount of voltage produced by the armatures.
The efficiency of the generators can also be enhanced by replacing slip rings by commutators. Most commutators are made up of two segments that are 180 degrees apart. During the rotation of the generator, the brushes get into contact with the commutator segments one at a time.
Magnets play significant role in the process of generating electricity; they enhance movement of current from one device to another. They also enhance the creation and movement of current within a magnetic field. However, wind turbines contain artificial magnets that are generated electrically.
Power converters play the role of converting electricity into different forms. They have the ability of converting electric current from either AC to DC or DC to AC. They have also the potential of converting electric voltage from voltage n to voltage i.
They are made up of devices such as diodes, power transistors, and silicon-controlled rectifiers. Power converters play significant role in enhancing the generation of useful electricity. For instance, they lead to production of controlled electricity that can be used domestically (Rivkin 2012, p.67).
In conclusion, the demand for renewable source of energy has played a significant role towards advancing the usage of wind energy as the source of electricity. It is not only a significant source of energy, but also a pollutant free source of energy. Its effect is greatly felt by great advancement in technology that has led to the production of effective turbines.
Wind turbines are made up of diverse elements that work as a unit. Some of the devices that make it include the blades, rotor, shaft, and the generator.
The surface area of the wind turbine blades plays a significant role towards the generation of electricity. The rotation of the blades leads to the spinning of the rotor which results to the rotation of the generator. On the other hand, the rotation of the devices within the generator results to the production of electricity.
List of references
Rivkin, D 2011, Wind Turbine Systems, Jones and Batlett Publishers, New York.
Rivkin, D 2012, Wind Turbine Operations, Maintenance, Diagnosis, and Repair, Jones and Batlett Publishers, New York.
Tong, W 2010, Wind Power Generation and Wind Turbine, WIT Press, Southampton.