National Hydrogen Association Conference Sacramento 2008 DSIGN, APPLICATIONS AND COMMRCIALIZATION OF FUL CLL POWRD AIRCRAFT Thomas H. Bradley PhD Candidate, George Woodruff School of Mechanical ngineering Georgia Institute of Technology David. Parekh VP Research & Director, United Technologies Research Center GTRI_B-1
Outline Motivation and introduction to fuel cell aircraft General design considerations for aviation fuel cells Near term applications for fuel cells in aviation Concluding remarks and future developments GTRI_B-2
Motivation for fuel cell powered aviation 1. nvironmental Compatibility Hydrogen Air fuel cells have no regulated emissions can use hydrogen generated from any source, including renewables National Research Council, For Greener Skies. Reducing nvironmental Impacts of Aviation. Washington, DC: National Academy Press, August 2002. Science 315, 796 (2007) Aviation and the Global Atmosphere, IPCC, 1999 GTRI_B-3
Motivation for fuel cell powered aviation High specific energy at very long endurances (liquid H 2 ) W fuel GTOW 1 Regenerative fuel cells To replace energy batteries On-board electricity generation Noise/Pollution constrained applications (General Aviation) High specific energy at small scales (gas, chem. and liquid H 2 ) < 300 W cruise, long range & endurance 2. Performance ngine: octane fuel, zero gasoline tank weight, tested efficiency AIAA 2003-671 Fuel cell: 0.65V/cell, tested efficiency, 10% is commercially available, 50% is representative of liquid GTRI_B-4 storage Lithium batteries: Anderman, M., California Air Resources Board, 2003
Motivating Question What are the general design requirements of fuel cell aircraft? GTRI_B-5
GTRI_B-6 General Design Considerations Constant mass aircraft (lectrochemical energy storage) D L gc C m L D L D s ( ) D L w C g C S m t 2 3 2 3 2 1 2 3 2 1 ρ D L D L gc C m C C mg vt mg vl & γ D L gc C m D T v & & &
General Design Considerations Conditions of use GTRI_B-7
General Design Considerations Reactant Storage Compressed Hydrogen Liquid Hydrogen Aqueous NaBH 4 Altitude Considerations 0.26 atm @ 10km -50C ambient 0.2 gh 2 0 (kg dry air) -1 Propane (SOFC) GTRI_B-8
Near term applications Small Scale UAVs Commercial Jet APU Solar-Regenerative Fuel Cell UAV General Aviation Long ndurance Large Scale GTRI_B-9
AeroVironment Hornet FH-Wiesbaden Hy-Fly DLR HyFish First Flight 3/21/2003 Duration 15 minutes over 3 flights Mass 0.17 kg Wingspan 0.381 m First Flight 7/9/2005 (Partial FC) 9/7/2005 (FC Only) Span 2 m Duration 90 s Mass 1.75 kg Max DC Power 65 W Georgia Tech First Flight 6/14/2006 Mass 16.4 kg, Span 6.58 m Duration 120 s (9/7/2006) ndurance ~ 45 min Max DC Power 550 W First Flight April 2007 Mass 6.1 kg, Span 1 m ndurance ~ 15 min Max DC Power 1 kw 2003 2005 2006 2007 AeroVironment Global Observer Cal-State LA Adaptive Materials KAIST 2008 First Flight 5/26/2005 Wingspan 15.24 m Liquid H 2 Storage ndurance ~24 hours Flown November 2005 Wingspan 2.2 m Duration 3 hr 19 min Mass 2.54 kg 3.1 kg Max DC Power 115 W First Flight 8/25/2006 Wingspan 5.49 m Weight 12.9 kg Max DC Power 650 W 6/2006 4.16 hrs SOFC First Flight 10/2007 Weight 2.5 kg Max DC Power 200 W GTRI_B-10
Fuel Cell UAV History GTRI_B-11
Small Scale UAV Comparison Powerplant Type Compressed Hydrogen PM Fuel Cell Propane Fueled Solid Oxide Fuel Cell Zinc Air Battery Lithium Polymer Battery Small Internal Combustion ngine Powerplant Specification 1000 DC Wh kg -1 [Moffitt et al., 2006] 660 DC Wh kg -1 [Crumm, 2006] 350 DC Wh kg -1 [Naimer et al., 2002] 166 DC Wh kg -1 [Anderman, 2003] 0.3 kg hr -1 @105W [Menon et al., 2007] m 3 2 m Calculated Range Calculated ndurance 186.4 Wh kg -1 64.4 Wh kg -3/2 1642 km 44.0 hr 157.2 Wh kg -1 49.9 Wh kg -3/2 1384 km 34.1 hr 108.0 Wh kg -1 28.4 Wh kg -3/2 951 km 19.4 hr 62.9 Wh kg -1 12.6 Wh kg -3/2 554 km 8.6 hr 125.5 Wh kg -1 35.6 Wh kg -3/2 1509 km 38.6 hr These comparisons assume that the airframe mass is the same for each technology. lectric motor mass (283g), fuel mass and fuel tankage mass are included where appropriate. For all powerplants, propeller efficiency is a constant 69% and for all electric powerplants, motor efficiency is a constant 71%. ach powerplant is sized to generate the same amount of propulsive energy as is consumed by the FC aircraft at cruise. For the internal combustion engine, the payload and aircraft control power is produced assuming an alternator of 80% efficiency. GTRI_B-12
Commercial Jet APU Kerosene to lectricity conversion efficiency Conventional Jet APUs 15% SOFC APUs 41%-60% System advantages Generation during flight Lower emissions Service intervals More-electric airplane NASA/TM-2004-213054 GTRI_B-13
Solar Regenerative Aircraft Advanced rechargeable batteries 200 Wh/kg Regenerative PM FCs >800 Wh/kg discharge 80% efficient charge >640 Wh/kg net http://www.nasa.gov/centers/dryden/news/newsreleases/2003/03-29_pf.html GTRI_B-14
General Aviation Boeing, 2002 Polytechnico de Torino, 2007 University of Stuttgart, 2007 WPI, 2003 No manned FC flown to date GTRI_B-15 http://www.uqm.com/press/news/07-25.html
Long ndurance Large Scale Liquid Hydrogen has very high specific energy PM, SOFC proposed >10,000 Wh kg -1 for LH2 Gasoline W fuel GTOW 1 13,000 Wh f kg -1 *35% 4500 Wh m kg -1 (HHV) Near-term endurance ~ 1 day to 1 week GTRI_B-16 http://www.pegasus4europe.com/pegasus/workshop/documents/presentations/bayraktar.pdf
Concluding Remarks FC UAVs are on the verge of commercial and tactical viability AeroVironment, Adaptive Materials, others Performance benefits of FCs are realizeable across many new and valuable applications Development of aviation specific FC and storage systems for these new applications Development of design methods, tradeoff studies, demonstrations GTRI_B-17 www.fcbt.gatech.edu/fuelcellairplane
Future Developments Summer 2008 Georgia Tech should demonstrate 24 hr, 13kg FC UAV Summer 2008 CSU-LA/OSU and Horizon Fuel Cells should set world distance and endurance records (<5kg) with FC UAV GTRI_B-18
National Hydrogen Association Conference Sacramento 2008 Thomas H. Bradley PhD Candidate, George Woodruff School of Mechanical ngineering Georgia Institute of Technology bradley@gatech.edu www.fcbt.gatech.edu/fuelcellairplane GTRI_B-19