
659
Appendix B: Useful Equations
for Fuel Cell Calculations
Thermodynamics
Ideal gas equation of state:
where
R ==
⋅
⋅
=Universalgas constant
kN m
kmol K
8 3145 831
445
kJ
kmol K⋅
The rst law of thermodynamics for a system undergoing a process:
12
QUUmVV mg ZZ W=−+−
()
+−+()
21 2
2
1
2
1
The rst law of thermodynamics for a control volume
Qmh
V
gZ
E
t
mh
V
gZ
CV ii
i
2
i
CV
ee
e
2
2
d
+++
=+ ++
∑
e
V
+
∑
W
Steady-state steady ow (SSSF) process
=
Qmh
V
gZ mh
V
gZ
CV ii
i
2
iee
e
2
e
+++
=++
∑
++
∑
W
CV