
148 Fuel Cells
n
nelec-genfcr
=− −()
1 φ ∆
, (4.95)
where ΔH
cr
is the enthalpy of formation for the chemical reaction.
4.8.3 Total Heat Generation in a Fuel Cell
Combining Equations 4.93a and 4.95, the total heat generation per cell is
given as
QnTS IE
genffrev cfcr
=−+−
+− −
()()()
1 nn
f
(4.96a)
or
QnTS IR
genff
2
cfcr f
=−+
+− −
() ()
1 (4.96b)
or
Q
ITS
nF
IR H
I
genf
e
2
cfcr
e
=
−
+
+− −
()
()
∆
∆1 . (4.96c)
For ϕ
f
= 1, that is, all fuel moles going through electrochemical reaction, the
equation reduces to
QI
TS
nF
gen
e
re
=
−
()
∆
for a cell (4.97a)
and
QNI
TS
nF
genc
e
re
=
−
()
∆
for a stack. (4.97b)
Anot ...