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Wind Turbine . P M V Subbarao Professor Mechanical Engineering Department IIT Delhi. The Ancient Energy Conversion Device…. The Art of Designing Large Blades Revived …. ONE TIME RESOURCE. Capital Resource. INCOMING RESOURCE. SOLAR ENERGY. CO 2 + H 2 O. PHTOSYNTHESIS. SOLAR
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Wind Turbine P M V Subbarao Professor Mechanical Engineering Department IIT Delhi The Ancient Energy Conversion Device…. The Art of Designing Large Blades Revived …
ONE TIME RESOURCE Capital Resource INCOMING RESOURCE SOLAR ENERGY CO2 + H2O PHTOSYNTHESIS SOLAR RADIATION WINDS VEGETATION VELOCITY CHEMICAL ENERGY THERMAL WAVE WIND ENERGY CLOUDS OCEAN THERMAL ENERGY FOSSILIZATION RAINS HYDRO ENERGY COAL FOSSIL FUEL PETROLEUM NATURAL GAS
Introduction • A wind turbine is a rotating machine which converts the kinetic energy of wind into mechanical energy. • If the mechanical energy is used directly by machinery, such as a pump or grinding stones, the machine is usually called a windmill. • If the mechanical energy is instead converted to electricity, the machine is called a wind generator, wind turbine, wind power unit (WPU), wind energy converter (WEC), or aerogenerator. • Horizontal Axis Wind Turbines (HAWT) • Vertical Axis Wind Turbines (VAWT)
Rotation = r *W Rotation = r *W Wind = V0 Wind = V0 a a Relative Wind = Vr Relative Wind = Vr Schematic of Wind Turbines
High Capital Cost • The largest wind farm in Australia is the Wattle Point wind farm in South Australia. • It took about one year to build, between June 2004 and June 2005. • It cost 180 million dollars, and has a total nameplate capacity of 91 MW. • The capacity factor – somewhere around 20%. • The “real” average power output capacity of the wind farm is 18.2 MW. • A capital cost of $9.9 Million (~ Rs50 Crore) per MW.
Cost Analysis of A Wind Turbine • Aerodynamic modeling is used to determine the optimum tower height, control systems, number of blades and blade shape. • Conventional horizontal axis turbines can be divided into three components. • The rotor component, which is approximately 20% of the wind turbine cost, includes the blades for converting wind energy to low speed rotational energy. • The generator component, which is approximately 34% of the wind turbine cost, includes the electrical generator, the control electronics. • The structural support component, which is approximately 15% of the wind turbine cost, includes the tower and rotor yaw mechanism.
Momentum Theory for an Ideal Wind Turbine • The rotor disc acts as a drag device slowing the wind speed Vo from far upstream of the rotor to u at the rotor plane and to u1in the wake. • The drag is obtained by a pressure drop over the rotor. • Close upstream of the rotor there is a small pressure rise from the atmospheric level poto p. • A discontinuous pressure drop ∆p over the rotor. • Downstream of the rotor the pressure recovers continuously to the atmospheric level. The Mach number is small and the air density is thus constant and the axial velocity must decrease continuously from Voto u1.
For a frictionless wind turbine: Dp : Fictitious Pressure Deficit Thrust Generated at the rotor Plane: