Numerical Analysis of Critical Performance Parameters of the
Sulzer Hexis Fuel Cell Stack
Pascal Held, Thomas HockerCCP – Center for Computational Physics
ZHW – University of Applied Sciences WinterthurWinterthur, Switzerland
Jeannette Frei, Jan HoffmannSulzer Hexis Ltd.
Winterthur, Switzerland
Fuel Cells - Science and Technology 2004
Introduction
- Simulation- Software validation
- Experimental setup- Hardware development
- Program support- GUI development
• The Project is supported by the Swiss Commission for Technology and Innovation (KTI)
• 1998 the CCP starts with SOFC simulation
• Goal: support of the HEXIS SOFC development with “virtual experiments”
• Partners:
Fuel Cells - Science and Technology 2004
Contents
• Environment
• Volume Averaging Method
• Model
• Sensitivity Analysis
• Results
Fuel Cells - Science and Technology 2004
Hexis Fuel Cell SystemSystemHXS 1000 Premiere
Stack
Fuel
Airafter burning zone
electrolyte(YSZ-ceramic)
Current collector (MIC)
Cell
Fuel Cells - Science and Technology 2004
Volume Averaging Method
EffectiveParameters
Fuel Cells - Science and Technology 2004
Vertical Temperature Gradient
Fuel Cells - Science and Technology 2004
Horizontal Temperatur Gradient
Fuel Cells - Science and Technology 2004
VAM Applied to SOFC
RepetitiveMIC-Element
MIC-Structure
•keff
eff
eff
eff(T,jq,xH2,...)
Effective ParametersSimulation of Transport Phenomena
• Reduced Geometric Complexity• Less computational effort
2D Effective Model:
Fuel Cells - Science and Technology 2004
Input:
Incorporation in 2D-Model
Nubs/element -Sigma -Kappa -
Permeability -Diffusion -
Database: multi.sfc
MIC -Gas Properties -
Database:reaction.sfc
Reaction prop. -
el. Cond.
Reaction
th. Cond.z-direction
th. Cond.x-direction
Perm
Diffusionnubs
Diffusion
Output:
effective Parameters
for 2D-Model
Solving3D withdetails
Comparing 3D with and without details
Fuel Cells - Science and Technology 2004
Parameter Variation
Original Direct Hole
Different MIC-Designs Contact Resistance
Manganite
RCont,Cath
Nubs MIC
Fuel Cells - Science and Technology 2004
Sensitivity Analysis
• Definition:Investigation into how projected performance varies along with changes in the key assumptions on which the projections are based.
• Goals:Identify parameters of major importance toa) find out if more accurate measurements requiredb) concentrate on parameters with optimization potential
Fuel Cells - Science and Technology 2004
Procedure
• Define upper and lower boundaries for input parameters (input parameters: material properties, geometries, operation condition)
• Evaluate output variables for all possible combinations of input parameters
• Statistical analysis of output variables
Fuel Cells - Science and Technology 2004
Input VariablesExample:• Free Volume in Anode/Cathode (Diff_x)• Ion conductivity of Electrolyte (SigmaTKx)• Contact Resistance (Contact_x)
DesignEase Screenshot
Fuel Cells - Science and Technology 2004
Required Simulations
DesignEase Screenshot
Follows 2n-law
Fuel Cells - Science and Technology 2004
Output Variables
• According to optimization goals
For example:• Area specific
resistance (ASR)• Temperature
Fuel Cells - Science and Technology 2004
Results
Parameter F (contact resistance cathode) has a major impact on overall performance
Fuel Cells - Science and Technology 2004
Further Information
CCP-ZHW http://www.ccp.zhwin.ch
Sulzer HEXIS Ltd. http://www.hexis.ch
NM GmbH http://www.nmtec.ch
NMSeses NMSeses (public domain version) with reduced capabilities is available under http://www.nmtec.ch
