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Fuel Cell Electric Aircraft Energy Challenge New Era of Aviation. James Dunn Advanced Technology Products Worcester, MA Electric Aircraft Symposium San Fran – May 2007. Fuel cells in Aviation. Electric UAV’s – Helios-NASA- Aerovironment Auxiliary Power – Boeing APU – Madrid +
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Fuel Cell Electric Aircraft Energy ChallengeNew Era of Aviation James Dunn Advanced Technology Products Worcester, MA Electric Aircraft Symposium San Fran – May 2007
Fuel cells in Aviation • Electric UAV’s – Helios-NASA- Aerovironment • Auxiliary Power – Boeing APU – Madrid + • Electric Airships – HAA – Lockheed Martin • Electric Propulsion - Manned aircraft - E-Plane
Fuel Cell Powered Glider Electric Glider
Benefits of Electric Aircraft • Increased Reliability – 1 moving part! • Improved Safety • QUIET - only propeller noise • Improved Comfort and Easy Maintenance • No Vibration • Reduced life-cycle costs • NO EMISSIONS !
Why Fuel Cells • High Efficiency – 2.5 X Gasoline Engines (60% vs. 23%) • Zero Emissions – Only Water Vapor No odors or fumes • Hydrogen Fuel – Sustainable and Renewable • High Energy Density– 300 - 600 WH/kg 2-3 X battery density
The Energy Challenge ! • Airplane needs 25kW Power @ 100 mph • 300 Mi. flight requires 75 kWh of Energy • Energy system Weight for 75kWh: - Lead Acid Batteries = 3000 kg - NiMH Batteries = 1500 kg - LiIon Batteries = 600 kg Fuel Cell system (+ 3 kg H2) = 165 kg (Gasoline Equivalent = 100 kg !)
The Challenge – Matching the energy density of Gasoline and IC Engines? Gasoline =13,200 WH/kg @ 20% effic. Net = 2600 WH/kg Best LiIon Batts = 200 WH/kg Still a 13:1 advantage for Gas!! (H2 = 30,000 WH/kg) Issues – Weight, Volume, HEAT, (+$$)
Hurdles & Issues • System Weight – Power Density/Effic. • Support Components – Power & Weight • Hydrogen Storage/Generation System • Heat Transfer methods & HEX System • Safety Issues – FAA + Ongoing • Customer Acceptance • Costly Technology
Hydrogen Sources • H2 Gas - High Pressure Tank – 5000 psi • Liquid Hydrogen – Cryo issues • Reformed Gasoline – CO, CO2 • Methanol/Ethanol – Direct or reformate • Ammonia (dissociated) – high yield • Sodium borohydride – safe, costly • Magnesium Hydride • Other ??
Selected Aircraft for Conversion • AGA Lafayette III • All Carbon Kit - 28’ Wing • We/Wo = .31 80 hp. Rotax 912 < 12 kW to Cruise Vne of 180+ kts
Aircraft Modeling for Hydrogen PEM Fuel Cell Motor ConversionNASA GRC MCR01 ULM Kit Plane Airbreathing Systems Analysis Office (NASA GRC) Systems Analysis Branch (NASA LaRC)
MCR01 ULM Fuel Cell ConversionPower Density Technology Sensitivity: PDPMAD = 1.06 kW/kg MCR01/Rotax 912 > 800 nm Range 800 Advanced Technology Fuel Cell Stack Power Density: 2.50 kW/kg Electric Motor Power Density: 2.30 kW/kg PMAD Power Density: 1.06 kW/kg Range = 336 nm Gross weight constantat 992 lb limit 2.3 2.5 2.0 2.3 1.8 2.1 1.7 1.9 PDMotor (kW/kg) PDStack (kW/kg) 1.5 1.7 1.3 1.5 Applied State-of-the-Art Technology Fuel Cell Stack Power Density: 1.57 kW/kg Electric Motor Power Density: 1.35 kW/kg PMAD Power Density: 1.06 kW/kg Range = 58 nm Further performance gains possible only if PMAD weight is reduced!
MCR01 ULM Fuel Cell Conversion Power Density Technology Sensitivity: PDPMAD = 2.60 kW/kg Advanced Technology Fuel Cell Stack Power Density: 2.50 kW/kg Electric Motor Power Density: 2.30 kW/kg PMAD Power Density: 2.60 kW/kg Range = 644 nm 2.3 2.5 2.0 2.3 1.8 2.1 1.7 1.9 1.7 1.5 1.3 1.5 PDStack (kW/kg) PDMotor (kW/kg) Gross weight constantat 992 lb limit Diminishing returns on range – The heavy compressed hydrogen tank limits further gains.
Program Objectives • Demonstrate viability of Fuel Cell powered electric propelled aircraft • Determine the optimum energy source • Analyze performance parameters & range • Design/develop High efficiency H2 PEM fuel cell • Integrate all components into Airframe and Test • Provide educational vehicle for students
Battery + Fuel Cell System Rqmts. Max Power - Batteries + Fuel Cell 75 kw Bus voltage 270 DC Net Stack power - cont. 17 kw No. of Cells 180 Efficiency 60 % Fuel Cell sys. Wt. (w/sgl.H2 tank) 80 kg Battery + Master Power Xtrol Wt. 50 kg Total Energy System Weight 130 kg
Fuel Cell System target weight • Stack (10-18kW) 25 kg • Blower (Compressor)+ duct 5 kg • Misc. BOP, plumbing, sensors 4 kg • HEX System w/Radiators 9 kg • DC-DC Up-convertor 7 kg • Fuel Cell Controller/mon. 5 kg • Dynatech Tank/Reg. 18 kg • Mounting + Misc. 5 kg • TOTAL fuel Cell System Weight 78 kg
New Lynntech Stack Design • Ultrahigh Efficiency (60%) • LightWeight – Metal (No Graphite) Bipolar Plates • Ambient Air Ops No Compressor No Hydrators
10 kW Fuel Cell Stack DESIGN SPECIFICATIONS • 180 cells • 300 cm2 active area • Generation 3 endplates • 10.25 kW @ 16 psia • 137 V • 75 A • 50 ˚C • 25 kg (hydrated) • 400 W/kg (@ 250 mA/cm2) • 720 W/kg (@500 mA/cm2) 18KW
Specific Energy Equivalent Total Fuel Cell System • Sgl. Tank - 78 kg System - 1 kg H2 = 24 kWH Net Energy Density = 24/78 = 307 WH/kg • Dbl. Tank – 96 kg system – 2 kg H2 = 48 kWH Net Energy Density = 48/96 = 500 WH/kg
Legend Fuel Electricity Liquid Coolant Control Power Conditioner, Regulation, Battery charger Motor Controller Batteries Hydrogen delivery/regulation Motor Fuel Cell Controller “Throttle” Outside Air Hydrogen storage Prop Control Electric controlled propeller Fuel Cell Stack Liquid to air heat exchanger Boeing Fuel Cell Glider Activities System Integration • System Lay – out Design • Motor and Drive • Fuel Cell Systems • Compressor • Heat exchanger • Pumps • Controller • Battery • Controllers and Converters • H2 System
Boeing Activities Electrical Subsystem • Electrical Subsystem Configuration • Power Balance • Power Demand • Motor & Drive • Controllers • Converters • Power Generation • Fuel Cells • Battery • Ground Auxiliary Power
Safety and Flight Testing • Major concern on all new Aircraft • Pilot and Airframe issues
Energy System Challenges • Energy Density • Thermal Management • Recharge or Refuel • Integration of Solar PV • Cost • Life • Reliability
Technology Evolution Area Today Future (2020) • Motor/Xtrol 2kw/kg 8-10 kw/kg • Fuel Cell Sys. 2kw/kg 5-6 kw/kg • Fuel/H2 Storage 7% H2 – Wt. 12-15 % • Energy Storage 200 WH/kg 5-800 WH/kg • Energy Produced 150 kWH 1000 kWH • Range 100 Mi 1000 mi.
Emerging Energy Solutions • Advanced Batteries – Lithium Ion + • High Density UltraCaps – EEStor – Other NanoStructured Electrodes – 500-2000 WH/kg • High Temp Fuel Cells – Higher power density • Advanced H2 Storage – New mat’ls + tanks • New Energy Gen. Sources - Many
Future Technology Options • Airframe Weight reduction • Improved Airframe/Propulsion Efficiency • Energy/Fuel Storage options • Higher Energy Density Storage Techs • New Designs with integrated storage • Improved Solar PV Design - Integration