Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 1
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
MNTINSTITUTE FOR
MICRO AND NANOTECHNOLOGY
Work package 3
Thermal management
17. November 2005
Patrik Müller
Andres Bolleter
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 2
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
MNTINSTITUTE FOR
MICRO AND NANOTECHNOLOGY
ContentContent
- Resume thermal concept
- Theoretical thermal resistance
- Thermal measurement
- Redesign vacuum insulation
- Status WP3
- Next steps
- Miscellaneous to other WP
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 3
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
MNTINSTITUTE FOR
MICRO AND NANOTECHNOLOGY
Air
Exhaust
Air
Exhaust
Fuel
Stack
Vacuum insulation /insulation
Insulation
Separation of in- andoutlet (heat exchanger)
Resume thermalResume thermal conceptconcept
Vacuum insulation /insulation
~ 2 cm
< 1
cm
~ 2 cm
Shape cylindrical or cubical
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 4
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
MNTINSTITUTE FOR
MICRO AND NANOTECHNOLOGY
Resume thermal conceptResume thermal concept
600 °C
~ 40°C
~7e4 W/(m2) ~3e3 W/(m2)
Vacuum chamberVacuum insulation
Insulation material
Stack
Air / Gas
Exhaust
Separation of Gases
•Vacuum chamber
•Vacuum chamber filled with porous insulation (WDS)
•Insulation material (WDS, Aerogel)
Three insulation-possibilities
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 5
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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MICRO AND NANOTECHNOLOGY
Steel foilSteel foil
Inner Vacuum-Housing
Vacuum-Insulation
Stack
Air / Gas
Exhaust
Outer Vacuum-Housing
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 6
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Thermally self-sustained Thermally self-sustained SOFCSOFC
- Idea is to use the exothermic oxidation reaction to locally sustain the
500-600°C which is needed for the electrochemical reaction
- Fuel utilization of experiments at ~ 1%
- Therefore 99% is released as heat
- OneBat-project efficiency 40%
- Insulation needed
Comments on the paper “A thermally self-sustained micro solid
oxide fuel-cell stack with high power density” *
* Z. Shao, S. M. Haile, J. Ahn, P. D. Ronney, Z. Zhan, S. A. Barnett, “A thermally self-sustained micro solid-oxide fuel-cell stack with high
power density”, 2005, Nature Publishing Group
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 7
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
MNTINSTITUTE FOR
MICRO AND NANOTECHNOLOGY
Theoretical thermal resistanceTheoretical thermal resistance
Simulation
“Stack”
1 2Th
W
T TR
I
Measurements
T2
T1
Insulation
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 8
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Thermal measurementThermal measurement
Dummy stack
Pmax ~ 12 W
Ø 8 x 4 mm
Microtherm Super G
Thermal conductivity
0.028 W/m*K @ 400°C
Aim: determination of thermal resistant
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 9
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Measurements Silica AerogelMeasurements Silica Aerogel
t1: 500°C
t2: 48°C
t3: 147°C
t4: 23°C
Dimensions: 14 x 30 x 45 mm
( : 8 °C)
t1
t2
t4
t3
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 10
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Measurements vacuum insulationMeasurements vacuum insulation
t1: 500°C
t2: 148°C
t3: 102°C
t4: 23°C
Pressure: 2*10-3 mbar
Dimensions: Ø 22 x 2 mm
( : 8 °C)
t1
t2
t4
t3
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 11
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Measurements vacuum insulationMeasurements vacuum insulation
Dummy-Stack Temperature
450
460
470
480
490
500
510
1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03
Vacuum [mbar]
Tem
per
atu
re [
°C]
Ptotal: 1.6 W to keep the stack temperature
t1
t2
t3
t4
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 12
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Redesign vacuum insulationRedesign vacuum insulation
Reduced buckling
- Matching thermal expansion
- Pre-stressing
Compact design
- Dimension: adaptation on simulation results
- Slimmer frame
Not tested yet: reliability
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 13
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Silica Aerogel reliabilitySilica Aerogel reliability
untreated
24 hours @ 600°C
1 hours @ 700°C
1 hours @ 800°C
1 hours @ 900°C
1 hours @ 1000°C
1 hours @ 1100°C
SEM picture by magic Brandon, MNW ETHZ
By now no information about long-term and insulation stability
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 14
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Status WP3Status WP3WP 3.1: Thermal System Design
Milestones
Month 3: - thermal insulation concept (T inside = 550°C, T outside = 50°C) (ZHW)Month 12: - system integration concept incl. thermal management concept heat exchanger design
compatible with GPU designs and micro-fabrication (ZHW)
Deliverables
Month 3: - design from ZHW NTB for fabrication
WP 3.2 Fabrication Concept of Thermal System
Milestones
Month 6: - test structures for validation of critical points of the concept (ΔT 500°C) (NTB)
Month 9: - test results of first designs
Month 12: - thermal system design demonstrator with simulated heat sources (dummy stack,
reformer, post-combustor) (NTB)
☺☺
☺☺
☺☺
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 15
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Next stepsNext steps
- Comparing first measurements with simulations
- If discrepancies to large: why ?
- Redesign of concept
- Reliability vacuum insulation
- Setup of second measurements: without gas-channels
- Closer to concept
- Comparing second measurements with simulations
- Third set of measurements with simulations
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 16
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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WP 1: structuring Pt-ElectrodeWP 1: structuring Pt-Electrode
Process: combination of lift-off and shadow mask Parameter:
- Development time
- Resist thickness
- Exposing dose
- Adhesion
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WP 2: gas processing unitWP 2: gas processing unitTest device: Foturan cannel 1 x 1 x 5 / 10 / 15 mm
Input needed for fabrication (month 6):
Final reformer design
3 designs of post-combustor
Drawings with all dimensions (CAD-File, dxf etc..)
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 18
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
MNTINSTITUTE FOR
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Thermo-mechanical simulationsThermo-mechanical simulations
What could be gained out of simulation
- Sensitivity of parameters can be evaluated
- Source of stresses can be localized easier then by
measurement
- Design-criteria
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 19
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
MNTINSTITUTE FOR
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Thermo-mechanical simulationsThermo-mechanical simulations
What inputs would these simulations require?
- Geometry
- Expansion coefficients
- E-module, Poisson Ratio
Where could thermo-mechanical simulations be used
- As an additional tool for system design
- To support cell-measurements, gaining insights
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 20
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
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Questions ?Questions ?
Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 21
NTBINTERSTATE UNIVERSITY OFAPPLIED SCIENCES OF TECHNOLOGY BUCHS
MNTINSTITUTE FOR
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Thermo-mechanical simulationsThermo-mechanical simulations
“ Resulting from elevated temperatures the major structural problem
foreseen with planar SOFCs is their thermal stresses” *
“ The stresses occurring in both cells are lying beyond the limit” *
“ principal stress peak arises at the beginning of the process (startup
process).” *
“ Largest stress occurs in a ceramic cell fuelled with prereformed
methane and it is located in the electrolyte layer at interface with the
anode”
* A. Selimovic, M. Kemm, T. Torisson, M. Assadi, “Steady state and transient thermal stress analysis in planar solid oxide fuel cells”,
Journal of Power Sources, 2005