Wind Turbine Ice Protection System Wind Turbine Ice Protection System (WTIPS) (WTIPS)

Erik Pederson, PhDErik Pederson, PhDKelly Aerospace Thermal SystemsKelly Aerospace Thermal Systems

Willoughby, OHIO, USAWilloughby, OHIO, USA

Hans Gedda, PhDHans Gedda, PhDMW InnovationsMW Innovations

Boden, SwedenBoden, Sweden

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AgendaAgenda

System BackgroundSystem BackgroundErosion Test Winter of 2007/2008Erosion Test Winter of 2007/2008V90 InstallationV90 Installation

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OverviewOverviewElectro Thermal Ice Electro Thermal Ice Protection SystemProtection SystemOriginally Developed Originally Developed through NASA Grantthrough NASA GrantCertified for use on several Certified for use on several aircraftaircraftDesigned to operate down Designed to operate down to to --40 Deg C40 Deg CHas been put through Has been put through Highly Accelerated Life Highly Accelerated Life Testing (HALT) down to Testing (HALT) down to --70 deg C 70 deg C

System TestingSystem TestingNASA Glenn Icing NASA Glenn Icing Research TunnelResearch TunnelMuch Wind Tunnel Much Wind Tunnel TestingTesting

Icing EncountersIcing Encounters

System can be used System can be used as a Deas a De--Ice System or Ice System or AntiAnti--Ice SystemIce SystemPulsed power Pulsed power technique to lessen technique to lessen average power usageaverage power usageShed zones raised to Shed zones raised to just above freezingjust above freezingNOTE: Show VideoNOTE: Show Video

Icing EncountersIcing Encounters

Heater ConstructionHeater Construction

Flexible Graphite Flexible Graphite MaterialMaterialContinuous sheetContinuous sheetEmbedded in Embedded in adhesives and adhesives and protective erosion protective erosion shieldshield

Heater ConstructionHeater Construction

Connections are made through copper bus bars Connections are made through copper bus bars embedded in heaterembedded in heaterHeater constructed as a single sheetHeater constructed as a single sheetDuPont Tedlar Erosion shieldDuPont Tedlar Erosion shieldLength, Width, Thickness is varied to match Length, Width, Thickness is varied to match available power and required power densityavailable power and required power densityAircraft Wing situations parting strip is requiredAircraft Wing situations parting strip is requiredRotating blades do not require the parting stripRotating blades do not require the parting strip

Heater InstallationHeater Installation

Heater formed as a flat Heater formed as a flat sheetsheetAdhesive backedAdhesive backed

Heater InstallationHeater Installation

Heat Gun utilized to Heat Gun utilized to warm heater to proper warm heater to proper temperaturetemperature

Heater InstallationHeater Installation

Heater is warmed to Heater is warmed to 85 deg C to allow 85 deg C to allow adhesive to flowadhesive to flowInstalled like a vinyl Installed like a vinyl decal decal Continuous heat is Continuous heat is applied to insure applied to insure proper bondingproper bondingNOTE: SHOW NOTE: SHOW VIDEOSVIDEOS

Installed HeaterInstalled Heater

Wind Turbine Ice ProtectionWind Turbine Ice Protection

Propose Propose protecting the protecting the leading edge of leading edge of the bladesthe bladesScale heaters to Scale heaters to match available match available powerpowerPulse power Pulse power between the between the bladesblades

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AdvantagesAdvantagesUniform Foil with no gaps heats up very quicklyUniform Foil with no gaps heats up very quickly–– Can be 1 deg / sec temp rise to 10 deg / sec temp rise dependingCan be 1 deg / sec temp rise to 10 deg / sec temp rise depending

on available poweron available powerLow Thermal Mass, drops in temperature very quickly to Low Thermal Mass, drops in temperature very quickly to prevent runbackprevent runbackQuick Temperature rise and external installation minimizes Quick Temperature rise and external installation minimizes energy usageenergy usageInstalled externally, blade modification not requiredInstalled externally, blade modification not requiredEasy to repair, heaters can be patchedEasy to repair, heaters can be patchedAdaptable to available power and voltageAdaptable to available power and voltageInstalled in field or in factoryInstalled in field or in factory

Erosion TestingErosion Testing

Installed sample Installed sample heaters with MW heaters with MW Innovations to Innovations to verify erosion verify erosion characteristics and characteristics and durabilitydurabilityFall of 2007 on a Fall of 2007 on a 1 MW turbine in 1 MW turbine in NNääsuddensudden, Sweden, Sweden

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Erosion TestingErosion Testing

Over 7000 hours of Over 7000 hours of time on bladetime on blade70% of time blades 70% of time blades are rotatingare rotatingHeaters are as they Heaters are as they were when installedwere when installed

Design ProcessDesign Process

Analyze Blade Airfoil Shape and Aerodynamic Analyze Blade Airfoil Shape and Aerodynamic parameters using LEWICEparameters using LEWICELEWICE is a software code developed by NASA to LEWICE is a software code developed by NASA to predict ice formation and power requirements on predict ice formation and power requirements on aerodynamic surfacesaerodynamic surfacesResults produce requirements for blade coverage Results produce requirements for blade coverage area and power densityarea and power densitySystem design is then a matching of available System design is then a matching of available power to coverage area requirementspower to coverage area requirements

V90 InstallationV90 InstallationBleikevare, Sweden in September 2008Bleikevare, Sweden in September 2008

V90 InstallationV90 Installation

Heaters installed while blades were on Heaters installed while blades were on ground in Dorotea, Swedenground in Dorotea, Sweden

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LayoutLayout

V90 Utilizes 93 heaters, 31 per bladeV90 Utilizes 93 heaters, 31 per bladeHeaters are wired in series to produce large Heaters are wired in series to produce large heater zonesheater zones–– Each zone contains 8 Each zone contains 8 –– 10 heaters10 heaters–– 7 zones per blade, 21 total zones7 zones per blade, 21 total zones

Power is pulsed between each zone to raise its Power is pulsed between each zone to raise its temperature and detemperature and de--ice the bladeice the blade1 1 –– 3 deg per second rise in temperature3 deg per second rise in temperatureFirst V90 utilizes 23 kW of PowerFirst V90 utilizes 23 kW of Power

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OperationOperation

Power is cycled around the wind turbine to Power is cycled around the wind turbine to maintain symmetrical / balanced deicing maintain symmetrical / balanced deicing characteristicscharacteristicsEach zone will take 20 Each zone will take 20 –– 40 seconds to de40 seconds to de--ice, depends on blade temperatureice, depends on blade temperatureTotal DeTotal De--Ice time 7 Ice time 7 –– 14 minutes14 minutesMeasure Relative Humidity, Blade Measure Relative Humidity, Blade Temperature, Ambient Temperature to Temperature, Ambient Temperature to determine when to dedetermine when to de--iceice

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PowerPower

With more power deWith more power de--ice cycle time ice cycle time decreasesdecreasesNumber of heater zones decreasesNumber of heater zones decreasesNumber of individual heaters remains the Number of individual heaters remains the samesameSystem could be operated as an AntiSystem could be operated as an Anti--Ice Ice SystemSystem

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PowerPower

Available Power for DeAvailable Power for De--ice changes number of ice changes number of zones and dezones and de--ice timeice timeV90 23 kW V90 23 kW –– 21 zones, 7 per blade21 zones, 7 per blade–– DeDe--ice time 7 ice time 7 –– 14 minutes14 minutes

> 50 kW > 50 kW –– approximately 9 zones, 3 per bladeapproximately 9 zones, 3 per blade–– DeDe--Ice time 3 Ice time 3 –– 6 minutes6 minutes–– Possibility of using system as an AntiPossibility of using system as an Anti--IceIce

> 100 kW > 100 kW -- approximately 3 zones, 1 per bladeapproximately 3 zones, 1 per blade–– DeDe--Ice time < 1 minuteIce time < 1 minute–– Capable or operating as AntiCapable or operating as Anti--Ice systemIce system

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Turbine #13 BleikevareTurbine #13 BleikevareHeaters have been installedHeaters have been installed

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Turbine #13 BleikevareTurbine #13 BleikevareTurbine has been erectedTurbine has been erected

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Turbine #13 BleikevareTurbine #13 BleikevareElectrical Control System install expected to Electrical Control System install expected to be finished near the end of January 2009be finished near the end of January 2009