Advertisement

Journal of Mechanical Science and Technology

, Volume 19, Issue 4, pp 1018–1026 | Cite as

Effects of key operating parameters on the efficiency of two types of pem fuel cell systems (High-Pressure and Low-Pressure operating) for Automotive Applications

  • Han-Sang Kim
  • Dong-Hun Lee
  • Kyoungdoug Min
  • Minsoo Kim
Article

Abstract

The proton exchange membrane (PEM) fuel cell system consisting of stack and balance of plant (BOP) was modeled in a MATLAB/Simulink environment. High-pressure operating (compressor type) and low-pressure operating (air blower type) fuel cell systems were considered, The effects of two main operating parameters (humidity and the pressure of the supplied gas) on the power distribution characteristics of BOP and the net system efficiency of the two systems mentioned above were compared and discussed. The simulation determines an optimum condition regarding parameters such as the cathode air pressure and the relative humidity for maximum net system efficiency for the operating fuel cell systems. This study contributes to get a basic insight into the fuel cell stack and BOP component sizing. Further research using multiobject variable optimization packages and the approach developed by this study can effectively contribute to an operating strategy for the practical use of fuel cell systems for vehicles.

Key Words

PEM Fuel Cell Fuel Cell System BOP High-Pressure Operating Low-Pressure Operating Net System Efficiency Component Sizing 

Nomenclature

A

Surface area of the stack (cm2)

a

Modeling constant

CP

Specific heat (J/kgK)

C1

Modeling constant

C2

Modeling constant

C3

Modeling constant

E

Open circuit voltage (V)

h

Heat transfer coefficient (W/cm2 K)

i

Current density (A/cm2)

imax

Current density that cause precipitous voltage drop (A/cm2)

i0

Exchange current density (A/cm2)

LHVH2

Lower heating value of hydrogen (J/kg)

mcw

Mass flow rate of stack coolant (kg/s)

mH2

Mass flow rate of hydrogen gas (kg/s)

Pbop

Parasitic load of BOP (W)

Pnet

Net system power (W)

Pstack

Stack gross electric power (W)

Rohm

Internal electrical resistance (ω cm2)

Tcw,m

Mean temperature of coolant (°C)

Ts,m

Mean temperature of stack (°C)

Vact

Activation overpotential (V)

Vconc

Concentration overpotential (V)

Vfc

Fuel cell voltage (V)

Vohm

Ohmic overpotential (V)

va

Constant (V)

vo

Voltage drop at zero current density (V)

Ws

Stack power (W)

ΔTew

Coolant temperature difference between stack inlet and stack outlet (°C)

ηnet

Net system efficiency

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Cunningham, J. M., Hoffman, M. A. and Friedman, D. J., 2001, “A Comparison of HighPressure and Low-Pressure Operation of PEM Fuel Cell Systems,”SAE paper No. 2001–01–0538.Google Scholar
  2. Friedman, D. J., Egger, A., Badrinarayanan, P. and Cunningham, J., 2001, “Balancing Stack, Air Supply, and Water/Thermal Management Demands for an Indirect Methanol PEM Fuel Cell System,”SAE paper No. 2001-01-0535.Google Scholar
  3. Jung, H. -M. and Koo, J. -Y., 2003, “Thermal and Flow Analysis in a Proton Exchange Membrane Fuel Cell,”KSME International Journal, Vol. 17, No. 9, pp. 1358–1370.Google Scholar
  4. Larminie, J. and Dicks, A., 2000, Fuel Cell Systems Explained, John Wiley & Sons.Google Scholar
  5. Nelson, D. J., Reinholtz, C. F. and von Spakovsky, M. R., 2000, “Systems Integration, Modeling and Validation of a Fuel Cell Hybrid Electric Vehicle,” M. S. Thesis, Virginia Polytechnic Institute and State University.Google Scholar
  6. Pukrushpan, J. T., 2003, “Modeling and Control of the Fuel Cell Systems and Fuel Processors,” Ph. D Thesis, The University of Michigan.Google Scholar
  7. Ronald, K. A. M. Mallant, 2003, “PEMFC Systems; the Need for High Temperature Polymers as a Consequence of PEMFC Water and Heat Management,”Journal of Power Sources, Vol. 118, pp. 424–429.CrossRefGoogle Scholar

Copyright information

© The Korean Society of Mechanical Engineers (KSME) 2005

Authors and Affiliations

  • Han-Sang Kim
    • 1
  • Dong-Hun Lee
    • 1
  • Kyoungdoug Min
    • 1
  • Minsoo Kim
    • 1
  1. 1.School of Mechanical and Aerospace EngineeringSeoul National UniversitySeoulKorea

Personalised recommendations