1. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 1 Work package 3 Thermal management 17. November 2005 Patrik Müller Andres Bolleter

2. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 2 Content - Resume thermal concept - Theoretical thermal resistance - Thermal measurement - Redesign vacuum insulation - Status WP3 - Next steps - Miscellaneous to other WP

3. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 3 Air Exhaust Air Exhaust Fuel Stack Vacuum insulation / insulation Insulation Separation of in- and outlet (heat exchanger) Resume thermal concept Vacuum insulation / insulation ~ 2 cm < 1 cm ~ 2 cm Shape cylindrical or cubical

4. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 4 Resume thermal concept 600 °C ~ 40°C ~7e4 W/(m 2 )~3e3 W/(m 2 ) Vacuum chamber Vacuum 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

5. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 5 Steel foil Inner Vacuum- Housing Vacuum-Insulation Stack Air / Gas Exhaust Outer Vacuum- Housing

6. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 6 Thermally self-sustained  SOFC -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

7. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 7 Theoretical thermal resistance Simulation “Stack” Measurements T2T2 T1T1 Insulation

8. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 8 Thermal measurement Dummy stack P max ~ 12 W Ø 8 x 4 mm Microtherm Super G Thermal conductivity 0.028 W/m*K @ 400°C Aim: determination of thermal resistant

9. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 9 Measurements 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

10. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 10 Measurements 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

11. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 11 Measurements vacuum insulation  P total : 1.6 W to keep the stack temperature t1 t2 t3 t4

12. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 12 Redesign vacuum insulation Reduced buckling -Matching thermal expansion -Pre-stressing Compact design -Dimension: adaptation on simulation results -Slimmer frame  Not tested yet: reliability

13. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 13 Silica 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

14. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 14 Status WP3 WP 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) ☺ ☺ ☺

15. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 15 Next 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

16. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 16 WP 1: structuring Pt-Electrode Process: combination of lift-off and shadow mask Parameter: -Development time -Resist thickness -Exposing dose -Adhesion

17. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 17 WP 2: gas processing unit Test 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..)

18. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 18 Thermo-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

19. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 19 Thermo-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

20. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 20 Questions ?

21. NTB INTERSTATE UNIVERSITY OF APPLIED SCIENCES OF TECHNOLOGY BUCHS MNT INSTITUTE FOR MICRO AND NANOTECHNOLOGY Patrik Müller, Andres Bolleter, Aziz Ibzazene OneBat Discovery - Work Package 3: Thermal Management - Page 21 Thermo-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