
44
and water speed decrease, the VRB begins to pro-
vide power to supply load demand at t = 28 s. The
fuel cell provides power again for load requirement
at 53 s while the VRB reaches its discharge limit.
The load demand changes from 350 W to 100 W
at 70 s and the excess power is again diverted to
the VRB.
The current variations of the solar cell, the fuel
cell, and the vanadium redox battery with load
changes and environmental conditions are shown
in Figure 8. These changes are reflected in the per-
formance of the fuel cell system and vanadium
redox battery. The stack current variation at t = 0 s
to 2 s is due to start-up transient and load demand, ...