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Challenges in fabricating large-area metallic materials for energy economyPaul H. [email protected] CMMI Workshop 2011Atlanta, GA
Chemical & Biomolecular EngineeringCornell University
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energy economy enters in a) the fabrication process and by the end-application energy-saving benefits. In this talk, be energy economy, we mean the energy economy provided by the end-product although the energy consumed in fabrication is important (as is life-cycle issues) E.g. for an Oerlikon Solar PV module, energy pay-back time is down to 1 year -- this for an end-product that will operate for 25-30 years. For Metglas, Amorphous Metal Distribution transformers operate even longer.
What do me mean by large-area? OS produces 2300 m^2/day of PV modules (more than half a foot-ball field per day). Metglas fabricates ribbon per day.1
energy economy solar energy at earths surface =1 10,000 X energy consumption of all humanity
11.9 Quad energy (electrical) consumed USA (2002) 26.3 Quad energy losses (2002)
1 Quad = 278,000 GW-h = 278 TW-h
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energy economy grid losses1 Quad = 278 TW-h
Hours in year: 24x365 = 8,760 h1.6 GW power plant x 1 year = 1.6 x 8,760 GW-h = 14,016 GW-h = 0.05 Quad3
energy economy grid losses
distributed
electricity31.2distribution(steel transformer)electrical
energy100heat68.8
1 Quad = 278 TW-h
Hours in year: 24x365 = 8,760 h1.6 GW power plant x 1 year = 1.6 x 8,760 GW-h = 14,016 GW-h = 0.05 Quad4
Source: Metglas sales literaturemetallic glass transformer cores
infrared images of transformerscrystalline core
amorphous metal coremicro-structure
33.8 TW-h energy (electrical) DT losses USA (2004) 27.0 TW-h potential savings by Amorphous Metal DT
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Source: PowerSource Summer 2007Metglas Conway, SC
EAS
amorphous core
power- distribution transformer (DT)
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Metglas fabrication
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Metglas challenge cast new ultra-efficient nano-crystalline alloys deeper understanding of fundamentals: high-speed contacting, solidification, transport
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example: fundamentals & product quality
Cornell: planar-flow spin-castingsurface tensionContact Zone9
high-speed contacting texture
Cast direction5 cm Wheel side Air side
C.J. Byrne et al., Capillary puddle vibrations linked to casting-defect formation in planar-flow melt spinning, Met. & Mat. Trans. B, 36B, pp. 445-456, 2006 10
origin of texture surface tension vs inertia
natural frequency: plucked liquid sphere (Rayleigh oscillation)
surface tensionC.J. Byrne et al., Capillary puddle vibrations linked to casting-defect formation in planar-flow melt spinning, Met. & Mat. Trans. B, 36B, pp. 445-456, 2006 11
BL Cox, in preparationexample: controlling texture
10 cm5 cm0.12 cm0.012 cm
Rounded Edge
Sharp Edge
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example: manipulating textureUS Patent 7,306,025 2007, Methods for continuous casting of a molten material US Patent 7,082,986 2006, PH Steen A system . . . for continuous casting . . .
5 cmBN Patterned Ribbon
Write-headErase-headRibbonContact zoneOverhead Pressure
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example: manipulating texture
LaserLensPrismByrne, CJ, et al., In-situ manipulation of cooling rates during planar-flow melt spinning processing, Mat. Sci. & Eng. A. 459, 172-181, 2007.14
photo-voltaic (PV) cell the sandwich
Source: Surek (2005)learning curve grid-parity goal
Source: RGS presentation
fabrication path
Source: OS Media Conference EU PVSEC 2010 Valencia, Spain 9/7/2010
Oerlikon Solar architecture thin-film bi-junctionMedia ConferenceEU PVSEC 2010Valencia, Spain9/7/2010 OS18
Source: http://www.oerlikon.com/solar/Oerlikon Solar (OS) batch fabricationMicromorph +TCO + front
plasma-enhancedchemical vapor deposition (PECVD)TCO +front glassStep 1Step 2back contact + Mm + TCO + front
laser processing (LSS laser)Micromorph + TCO +front glassStep 3
TCO +front glass
front glasslow-pressurechemical vapor deposition (LPCVD)
OS ThinFab manufacturing
Source: http://www.oerlikon.com/solar/thinfab/ 9/2010Source1: OS ThinFab FactSheetSource2: OS Media Conference EU PVSEC 2010 Valencia, Spain 9/7/2010
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OS challenges market ThinFab, increase efficiency & innovate
fend-off competing technological alternatives
deeper understanding of fundamentals: high-speed deposition, laser surface-processing
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RGS: alternative fabrication strategy
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RGS continuous-casting of Si wafer
RGS: area rate = 1,350 m^2/day. 23
RGS challenges achieve quality while maintaining productivity deeper understanding of fundamentals: high-speed contacting, polycrystalline seeding and solidification
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Ack: NSF CMMI 07278613; Metglas; RGS; Alcoasummary: fabrication science our challenge! deeper understanding needed of fundamentals of high-speed contacting lubrication laser-processing solidification transport metrology
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gassolid 1liquidinterfacesInterfaces: liquid/solid; gas/liquid/solid; gas/liquid/solid I/solid II; acknowledgements25