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7. Next, disconnect the connecting tube to release a little hydrogen into the air and verify a
similar plot as shown below in Figure 1.5. Notice that the resistance reading is 2.4 ohms
– not 1 ohm as you might expect. More about this in the Analysis section below.
Figure 1.5 – Purging the Hydrogen Tube of Gasses
Analysis:
As the plot in Figures 1.4 and 1.5 illustrates, the fuel cell's voltage, current and power rapidly
increase with the fuel cell purging process. When the fuel cell system is first setup, there is a
small amount of air in the tubes and the hydrogen container, so the fuel cell consumes impure
hydrogen. As a result the fuel cell cannot reach its optimum performance.
However, when the tube is removed, impure gasses along with some water vapor are expelled
and, thus, clear the tube for pure hydrogen production the next time the fuel cell is electrolyzed.
This is why the procedure should be repeated at least one more time in order to clear the
connecting tubes and balloon of impure gasses.
Now to the 2.4 ohm reading....
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