This article aims to develop an entropy based method of systematically improving efficiency of fuel cells. Entropy production of both electrochemical and thermofluid irreversibilities is formulated based on the Second Law. Ohmic, concentration, and activation irreversibilities occur within the electrodes, while thermal and friction irreversibilities occur within the fuel channel. These irreversibilities reduce the overall cell efficiency by generating voltage losses. Unlike past studies, this article considers fuel channel irreversibilities within the total entropy production, for both solid oxide fuel cells (SOFCs) and proton exchange membrane fuel cells (PEMFCs). Predicted results of entropy production are shown at varying operating temperatures, surface resistances, and channel configurations. Numerical predictions are compared successfully against past measured data of voltage profiles, thereby providing useful validation of the entropy based formulation. The Second Law stipulates the maximum theoretical capability of energy conversion within the fuel cell. Unlike past methods characterizing voltage losses through overpotential or polarization curves, the entropy based method provides a useful alternative and systematic procedure for reducing voltage losses.

1.
Vargas
,
J. V. C.
,
Ordonez
,
J. C.
, and
Bejan
,
A.
, 2004, “
Constructal Flow Structure for a PEM Fuel Cell
,”
Int. J. Heat Mass Transfer
0017-9310,
47
(
19-20
), pp.
4177
4193
.
2.
Naterer
,
G. F.
, 2004, “
Adaptive Surface Micro-Profiling for Microfluidic Energy Conversion
,”
J. Thermophys. Heat Transfer
0887-8722,
18
(
4
), pp.
494
501
.
3.
Chen
,
F.
,
Wen
,
Y. Z.
,
Chu
,
H. S.
,
Yan
,
W. M.
, and
Soong
,
C. Y.
, 2004, “
Convenient Two-Dimensional Model for Design of Fuel Channels for Proton Exchange Membrane Fuel Cells
,”
J. Power Sources
0378-7753,
128
, pp.
125
134
.
4.
Yang
,
H.
,
Zhao
,
T. S.
, and
Cheng
,
P.
, 2004, “
Gas-Liquid Two-Phase Flow Patterns in a Miniature Square Channel With a Gas Permeable Sidewall
,”
Int. J. Heat Mass Transfer
0017-9310,
47
(
26
), pp.
5725
5739
.
5.
Naterer
,
G. F.
,
Hendradjit
,
W.
,
Ahn
,
K. J.
, and
Venart
,
J. E. S.
, 1998, “
Near-Wall Microlayer Evaporation Analysis and Experimental Study of Nucleate Pool Boiling on Inclined Surfaces
,”
ASME J. Heat Transfer
0022-1481,
120
(
3
), pp.
641
653
.
6.
Martin
,
J.
,
Oshkai
,
P.
, and
Djilali
,
N.
, 2005, “
Flow Structures in a U-Shaped Fuel Cell Flow Channel: Quantitative Visualization Using Particle Image Velocimetry
,”
ASME J. Fuel Cell Sci. Technol.
1550-624X,
2
(
1
), pp.
70
80
.
7.
Adeyinka
,
O. B.
, and
Naterer
,
G. F.
, 2005, “
Particle Image Velocimetry Based Measurement of Entropy Production with Free Convection Heat Transfer
,”
ASME J. Heat Transfer
0022-1481,
127
(
6
), pp.
615
624
.
8.
Naterer
,
G. F.
,
Glockner
,
P. S.
,
Chomokovski
,
S. R.
,
Richardson
,
G.
, and
Venn
,
G.
, 2005, “
Surface Micro-Grooves for Near-Wall Exergy and Flow Control: Application to Aircraft Intake Deicing
,”
J. Micromech. Microeng.
0960-1317,
15
, pp.
501
513
.
9.
Warshay
,
M.
, and
Prokopius
,
P.
, 1995, “
Coordinated Fuel Cell System Programs for Government and Commercial Applications—Are We in a New Era?
,” Paper No. AIAA-1995-403, AIAA 33rd Aerospace Sciences Meeting and Exhibit, Reno, NV, Jan. 9–12.
10.
Warshay
,
M
, 1978, “
ECAS Phase I Fuel Cell Results (Energy Conservation Alternatives Study)
,”
J. Energy
0146-1412,
2
(
1
), pp.
46
52
.
11.
Bove
,
R.
, and
Sammes
,
N. M.
, 2005, “
Optimal SOFC Size Design for Minimal Cost of Electricity Achievement
,”
ASME J. Fuel Cell Sci. Technol.
1550-624X,
2
(
1
), pp.
9
13
.
12.
Lu
,
Y.
,
Schaefer
,
L.
, and
Li
,
P.
, 2005, “
Numerical Simulation of Heat Transfer and Fluid Flow of a Flat-Tube High Power Density Solid Oxide Fuel Cell
,”
ASME J. Fuel Cell Sci. Technol.
1550-624X,
2
(
1
), pp.
65
69
.
13.
Wu
,
J.
, and
Liu
,
Q.
, 2005, “
Simulation-Aided PEM Fuel Cell Design and Performance Evaluation
,”
ASME J. Fuel Cell Sci. Technol.
1550-624X,
2
(
1
), pp.
20
28
.
14.
Sundaresan
,
M.
, and
Moore
,
R. M.
, 2005, “
Polymer Electrolyte Fuel Cell Stack Thermal Model to Evaluate Sub-Freezing Startup
,”
J. Power Sources
0378-7753,
145
, pp.
534
545
.
15.
Naterer
,
G. F.
, 2003, “
Temperature Gradient in the Unfrozen Liquid Layer for Multiphase Energy Balance with Incoming Droplets
,”
ASME J. Heat Transfer
0022-1481,
125
(
1
), pp.
186
189
.
16.
Naterer
,
G. F.
, 2002,
Heat Transfer in Single and Multiphase Systems
,
CRC Press
, Boca Raton, FL.
17.
Bharadwaj
,
A.
,
Archer
,
D. H.
, and
Rubin
,
E. S.
, 2005, “
Modeling the Performance of a Tubular Solid Oxide Fuel Cell
,”
ASME J. Fuel Cell Sci. Technol.
1550-624X,
2
(
1
), pp.
38
44
.
18.
Chan
,
S. H.
, and
Xia
,
Z. T.
, 2002, “
Polarization Effects in Electrolyte/Electrode-Supported Solid Oxide Fuel Cells
,”
J. Appl. Electrochem.
0021-891X,
32
, pp.
339
347
.
19.
Ghadamian
,
H.
, and
Saboohi
,
Y.
, 2004, “
Quantitative Analysis of Irreversibilities Causes Voltage Drop in Fuel Cell (Simulation and Modeling)
,”
Electrochim. Acta
0013-4686,
50
, pp.
699
704
.
20.
Kong
,
C. S.
,
Kim
,
D. Y.
,
Lee
,
H. K.
,
Shul
,
Y. G.
, and
Lee
,
T. H.
, 2002, “
Influence of Pore-Size Distribution of Diffusion Layer on Mass-Transport Problems of Proton Exchange Membrane Fuel Cells
,”
J. Power Sources
0378-7753,
108
(
1–2
), pp.
185
191
.
21.
Kim
,
J. W.
,
Virkar
,
A. V.
,
Fung
,
K. Z.
,
Mehta
,
K.
, and
Singhal
,
S. C.
, 1999, “
Polarization Effects in Intermediate Temperature, Anode-Supported Solid Oxide Fuel Cells
,”
J. Electrochem. Soc.
0013-4651,
146
, pp.
69
78
.
22.
Beavers
,
G. S.
, and
Joseph
,
D. D.
, 1967, “
Boundary Conditions at a Naturally Permeable Wall
,”
J. Fluid Mech.
0022-1120,
30
, pp.
197
207
.
23.
Bossel
,
U.
, 2003. “
Efficiency of Hydrogen Fuel Cell, Diesel-SOFC-Hybrid and Battery Electric Vehicles
,” European Fuel Cell Forum, Morgenacherstrasse, Germany, October 20.
24.
Larminie
,
J.
, and
Dicks
,
A.
, 2003.
Fuel Cell Systems Explained
,
John Wiley and Sons
, Etobicoke, Ontario, Canada.
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