HAWT Technology Research

HAWT Technology Research even Axis suggestion Turbines (HAWT), be the most commonly used malar see turbine.HAWTs check a similar design to a windmill, with blades that look like a propeller, spinning around a horizontal axis. Figure 1 Typical HAWTAll the roles (blades, shaft, gearbox, generator) are located at the top of the tower. The blades must face into the wind and yaw into position every time the wind anxiety changes. The shaft axis is horizontal to the ground. The wind hits the blades of the turbine where lift causes rotation. The shaft has a gear on the end coupled to a gearbox which turns a generator. The generator produces electricity and sends this either to force out grid or electrical equipment requiring power. The wind turbine also has some key elements that adds to its efficiency. Inside the Nacelle (or head) is an anemometer, wind vane, and controller that read the advance and direction of the wind. As the wind changes direction, a motor (yaw motor) turns the nacelle so the blades are always facing the wind. The power source also comes with a safety feature. In case of extreme winds the turbine has a break that can slow the shaft speed. This is to inhibit any damage to the turbine in extreme conditions. See Figure 2. Figure 2 Internal components of a typical HAWTThe merits of horizontal axis wind turbine over vertical axis wind turbine can be seen in Table1 Benefits of HAWTs vs VAWTHAWT VS VAWTNOPOWER GENERATION efficiencyHORIZONTAL AXISVERTICAL AXIS1POWER GENERATION EFFICIENCY50% 60%ABOVE 70%2ROTATING SPEED spicyLOW3EFFECT ON BIRDSGREATSMALL4GEAR BOXABOVE 10KW YESNO5BLADE ROTATION quadriceps femorisQUITE LARGEQUITE SMALL 6NOISE5-60 Db0-10 Db7STARTING WIND SPEEDHIGH(2.5-5m/s)LOW (1.5-3 m/s)Horizontal Axis Wind Turbine BladeThe blade is one of the most eventful components of a wind turbine. It is required to have the best materials, manufacturing, analysis and testing to expect aerodynamic loads, gravitational loads, inertia loads an d operational loads throughout its lifetime. Therefore, the structural design process has a decisive and critical influence on the overall performance of the blade. The structural design of a HAWT blade involves many considerations such as strength, stability, cyclic loading, cost and vibration. Reducing the mass is a key requirement for a successful blade design. A lighter blade will not only exert lower loads on the rest components of the HAWT, but also foreshorten the cost. This is a benefit to the entire turbine system, including the support body and the foundation. However, the recent approach results in material layup with high component thicknesses. Blade mass as a result often does not exhibit a satisfactory structural response. There is huge potential to reduce the amount of material used in the blades manufacture to minimise its mass. The process of structural blade optimisation to reduce mass and increase its mechanical properties is an important area of development wor thy of in-depth research. Table 1 details various HAWTs and their rotor weights. Table 2 Selection of turbine size and weight configurationsTurbine Name drive home or StallRotar dia (m)No of BladesNacelle and Rotor Weight (kg)Weight per Swept Area (kg/m)Mitsubishi MWT-1000 (1 MW)P573unspecifiedNordex N90 (2.3 MW)P90384,50013.3Nordex N80 (2.5 MW)P80380,50016Repower 5M (5 MW SiemensP1263unspecifiedSWT-3.6-107 (3.6 MW) SiemensP1073220,00024.5SWT-2.3-93 (2.3 MWP933142,00020.9Gamesa G90-2MW (2 MWP903106,00016.7Gamesa G58-850 (850 kW)P58335,00013.3Enercon E82 (2 MW)P823unspecifiedGE wind 3.6sl (3.6 MW)P1113unspecifiedVestas V164 (7.0 MW)P1643unspecifiedVestas V90 (2 MW)P903106,00016.7Vestas V82 (1.65 MW)P82395,00018Advantages of HAWT over VAWTAxis of RotationIt is the main and biggest difference. As the name states, Horizontal Axis Wind Turbine has its axis of rotation parallel to the ground and Vertical Axis Wind Turbine has its axis of rotation perpendicular to ground. lean of blades wo rking at a timeIf we take a 3-bladed wind turbine for example, then in a Horizontal Axis Wind Turbine, all triple blades work at once. whilst in a Vertical Axis Wind Turbine only blade works at a time.Working wind directionVAWTs are omni directional and work in all wind directions while HAWTs only works in a specific wind direction and have to yaw to face the wind before they can begin operation. When wind direction changes the stops, and has to yaw into position.Efficiency at a given wind speedBecause all the blade of HAWT work at the same time, its efficiency is much greater than the VAWT.REFERENCESPeter J. Schubel * and Richard J. Crossley Faculty of Engineering, Division of Materials, Mechanics and Structures, University of Nottingham, University Park, Nottingham NG7 2RD, UKVeritas, D.N. Design and Manufacture of Wind Turbine Blades, Offshore and Onshore Turbines Standard DNV-DS-J102 Det Norske Veritas Copenhagen, Denmark, 2010.Dolcera.com(online)