2/7/20131The University of Iowa Intelligent Systems LaboratoryTurbine Design IAndrew KusiakIntelligent Systems Laboratory2139 Seamans CenterThe University of Iowa Iowa City, Iowa 52242 - [email protected]: 319-335-5934 Fax: 319-335-5669http://www.icaen.uiowa.edu/~ankusiakThe University of Iowa Intelligent Systems LaboratoryOutline Basic turbine designs Turbine loads and blades Design for noise Design trade-offsThe University of Iowa Intelligent Systems LaboratoryWind TurbinesWind TurbineWind FarmThe University of Iowa Intelligent Systems LaboratoryVirtual Wind Plant Tourhttp://www.midamericanenergy.com/wind/html/resource5.asp2/7/20132The University of Iowa Intelligent Systems LaboratoryTurbine Classification:Axis Direction• Horizontal axis • Vertical axisMathew (2006)The University of Iowa Intelligent Systems LaboratoryHorizontal AxisEldridge (1980)The University of Iowa Intelligent Systems LaboratoryNew Design Example: WindCube Small in size compared to the standard horizontal WT  Designed for roof placementin urban and rural areas Power amplification 22 x 22 x 12 feet in size,  60kW output  Cut-in speed 5m/h Annual power of 160,000 kWh at average wind speed of 15 mphEquivalent to 50 feet diameter horizontal WT rotorGreen Energy Technologies http://www.getsmartenergy.com/The University of Iowa Intelligent Systems LaboratoryWindCubeCombining existing design concepts works2/7/20133The University of Iowa Intelligent Systems LaboratoryExamples: Residential WTsSouthwest Windpower http://www.windenergy.comThe University of Iowa Intelligent Systems LaboratoryWindTamer™ Turbine http://www.awrwindgardens.com/The University of Iowa Intelligent Systems LaboratoryResidential WTWindPower 2010 The University of Iowa Intelligent Systems LaboratoryVertical Axis TurbineEldridge (1980)2/7/20134The University of Iowa Intelligent Systems LaboratoryVertical Axis Turbines6,000 WWRE 060WRE 007750 WWRE 0303,000 Whttp://www.ekosklep.ekologika.com.pl/index.php/cPath/46_87The University of Iowa Intelligent Systems LaboratoryWind Turbine Historyhttp://en.wikipedia.orgThe University of Iowa Intelligent Systems LaboratoryWind Turbine Historyhttp://en.wikipedia.orgThe University of Iowa Intelligent Systems LaboratoryWind Turbine HistoryErrichello and Muller, GeartechDarrieus wind turbines2/7/20135The University of Iowa Intelligent Systems LaboratoryWind TurbineHistoryErrichello and Muller, GeartechThe University of Iowa Intelligent Systems LaboratoryWind Turbine Historyhttp://en.wikipedia.orgThe University of Iowa Intelligent Systems LaboratoryWind Turbine Historyhttp://en.wikipedia.orgOffshore wind turbines near CopenhagenThe University of Iowa Intelligent Systems LaboratoryWind-Rotor Position Upwind turbines Rotor is facing the windDownwind turbinesRotor placed on the lee side of the towerMathew (2006)2/7/20136The University of Iowa Intelligent Systems LaboratoryWhy Horizontal Axis WT?Mathew (2006), p. 22CPPower coefficient(Mathew (2006), p. 14Tipspeedratio (TSR)(Mathew (2006), p. 15Tip speedWind speedTSR =The University of Iowa Intelligent Systems LaboratoryTurbine Componentshttp://www.galileoscientific.com/wind_energy.jpgThe University of Iowa Intelligent Systems LaboratoryOperating Principles of Wind Turbineshttp://www.awea.org/faq/basicop.htmlThe wind passes over both surfaces of the airfoil shaped blade. It passes more rapidly over the longer (upper) side of the airfoil, creating a lower-pressure area above the airfoil. The pressure differential between top and bottom surfaces results in a force, called aerodynamic lift. The University of Iowa Intelligent Systems LaboratoryOperating Principles of Wind TurbinesIn an aircraft wing, this forces causes the airfoil to "rise," lifting the aircraft off the ground. Since the blades of a wind turbine are constrained to move ina plane with the hub as its center, the lift force causes rotation about the hub. In addition to lift force, a "drag" force perpendicular to the lift force impedes the rotor rotation. A prime objective in wind turbine design is for the blade tohave a relatively high lift-to-drag ratio. This ratio can be varied along the length of the blade to optimize the turbine’s energy output at various wind speeds.http://www.awea.org/faq/basicop.html2/7/20137The University of Iowa Intelligent Systems LaboratoryWT Major ComponentsSterzinger and Svrcek, NREP, 2004The University of Iowa Intelligent Systems LaboratoryTurbine StructureBlaabjerg and Chen (2006)The University of Iowa Intelligent Systems LaboratoryHubhttp://www.richterag.de/english/highlights/windkraftanlageThe University of Iowa Intelligent Systems LaboratoryGearless Turbinehttp://www.world-wind-energy.info/Enercon2/7/20138The University of Iowa Intelligent Systems LaboratoryPower Flow Concepthttp://www.world-wind-energy.info/EnerconThe University of Iowa Intelligent Systems LaboratoryUpwind Turbines Upwind designs avoid the wind shade behind the tower as it faces the wind  The vast majority of wind turbines have this designAdvantages:The University of Iowa Intelligent Systems LaboratoryUpwind Turbines The basic drawback of upwind designs is that the rotor needs to be rather inflexible, and placed at some distance from the tower (at an increased cost) A yaw mechanism always needed to keep the rotor facing the wind Some wind shade in front of the tower gets created, i.e., the windbends away from the tower before it reaches the tower itselfEach time the rotor passes the tower, the power from the wind turbine minimally affectedDisadvantages:The University of Iowa Intelligent Systems LaboratoryDownwind TurbinesAdvantages:They can be built without a yaw mechanism, if the rotor and nacelle are designed so that the nacelle follow passivelythe windThe rotor can be made more flexible. This helps structural dynamics and it reduces turbine weight, i.e., thinner blades bend, thus taking part of the load off the tower  The basic drawback is the fluctuation in the wind power due to the rotor passing through the wind shade of the tower  Larger fatigue loads on the turbine than with an upwind designDisadvantages:2/7/20139The University of Iowa Intelligent Systems LaboratoryTurbine ClassesFour basic classes defined by the wind speed and turbulence data The wind data is characterized by: the maximum wind speed to be expected as a mean value over 10 min, the so-called reference wind velocity (veref) the mean