
426 Fuel Cells
start-up under cold environment conditions using the same integrated ow
channel ow loop.
Example 10.2
Consider an 80-kWe PEM fuel cell stack with an operating power ef-
ciency of 55%. Determine (i) heat generation rate and (ii) mass ow rate
of water as coolant assuming 60% of the heat is picked up by the coolant
uid and assuming a coolant temperature rise of ΔT
c
= 10°C.
Solution
i. Net heat generation can be estimated from the denition of
thermal efciency as
η
th
e
en
=
+
W
WQ
.
Circulating
pump
Heater
Ai
2
Radiator
FIGURE 10.9
Schematic of an integrated cooling/heating system.