| How Does Temperature Affect the Electrical Output of a Fuel Cell? | |
Researched by Kaitlin M.
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The purpose of this experiment was to see if the electrical output of a fuel cell changed when operated at different temperatures.
I became interested in this idea when I was reading a newspaper article saying that auto manufactures might start making cars operated by fuel cells. I wondered if the fuel cell would be a good choice for a car since temperatures vary so much around the country. Florida is warm all year, but Alaska varies from cool to freezing.
The information gained from this experiment could help the drivers of America to decide if they really want a fuel cell car.
My hypothesis was that the fuel cell would work the best at 2°C.
I based my hypothesis on Mrs. Patti Gustin, a high school science teacher. She said, "Reactions that release energy will work best at lower temperatures." So that is why I thought that the fuel cell would work best at 2° C instead of 32°C, 22°C, or 12°C.
The constants in this study were:
- The multimeter used to measure the electrical output
- The amount of trials (2 trials)
- The type of stop watch
- The electrical load on the fuel cell
- The type of measurement
- Fuel for fuel cell (hydrogen and oxygen)
- The type and size of the fuel cell
- Purity of water going into fuel cell (distilled)
- Tool to separate hydrogen and oxygen (solar panel)
- The type of light used on solar panel (lamp light)
- Tool used to keep fuel cell cool when it is being charged (white wash cloth)
The manipulated variable was the temperature at which the fuel cell
runs.
The responding variable was how many volts the fuel cell produced.
To measure the responding variable I used a multimeter.
| QUANTITY | ITEM DESCRIPTION |
| 1 | hydrogen-oxygen fuel cell |
| 1 | multimeter (voltmeter) |
| 1 | room/bath room |
| 1 | distilled water |
| 1 | solar panel |
| 1 | refrigerator |
| 1 | big heater |
| 1 | mini heater |
| 1 | digital stopwatch |
| 1 | white washcloth |
| 1 | 60-watt light |
1. Get the fuel cell ready.
a. Take off the protector tubes on the side.
b. Use the syringe to pump water through the side of the cell.
c. Stop when you put one ml of water into the cell.
2. Do test one at 2 degrees Celsius
a. Put 47 ml of water into the container that holds the gas containers.
Put the fuel cell into the location at 2°C for at least 1 hour.
b. Shine a lamp straight onto the middle of the solar panel, with the
panel flat, to break the water a part until
the gas containers have
gas bubbles coming out of the top. Cover the
fuel cell covered
with a white washcloth to avoid accidentally
heating up the fuel cell. 
c. Start the stopwatch
d. Use a voltmeter to measure the voltage output of the cell
every
minute. For 11 minutes.
e. Stop the stopwatch when the fuel cell runs out of hydrogen
and oxygen.
f. Conduct another trial. Use the same directions above except store
the fuel cell at this temperature for 30 minutes prior to charging it.
3.Do test two at 12 degrees Celsius
a. Repeat steps 2a-2g.
4. Do test three at 22 degrees Celsius
a. Repeat steps 2a-2g.
5. Do test four at 32 degrees Celsius
a. Repeat steps 2a-2g.
6. Graph the data
a. Find the mean for both trials at each temperature.
b. Find the overall mean for each temperature.
c. Make a graph of the minute-by-minute data for the mean output
at each temperature.
The original purpose of this experiment was to see if the electrical output of a fuel cell changed when operated at different temperatures.
The results of the experiment were that temperature made very little difference. The average output varied from 0.71 volts to 0.74 volts which was less than a 5% difference, too little to say that a true difference existed.
At 2° and 12° the average output was 0.71 volts. At 22° the average output was 0.73 and at 32° it was 0.74 volts.
My hypothesis was that the fuel cell would work the best at 2°C.
The results indicate that this hypothesis should be rejected. In fact the output at 2°C was one of the lowest, if any difference in voltage actually exists due to temperature, then it would appear that as temperature increased, so did voltage (but only a tiny bit.)
Because of the results of this experiment, I wonder if the purity of the water used in my fuel cell might affect output. I also wonder if the large, powerful fuel cells built by the auto manufacturers work the same way as my little model. I also wonder if the age of the fuel cell affects its output. For example, does a brand new fuel cell act the same as one that has been used 1000 times.
If I were to conduct this project again I would run many more trials
at each temperature level. I would use three or more different fuel
cells to see if all behaved the same. I would also be extremely careful
to make sure the fuel cell stayed at the correct temperature at all times
during a certain trial. I would also try really hard to locate a true expert
in fuel cell technology who could give me better ideas about how to proceed
with my experiment. As it was, I had to follow the instruction manual
for my car and that might not have been the best approach.
I would like to thank a few people that helped me with this project.
- I would like to thank both of my parents, especially my Dad. They helped me so much by buying me all of my materials, helping me understand the fuel cell, and most of all having patience even though all of the pre-experiments.
- I would also like to thank my science teacher for all of the tips and grading of papers and handouts.
- I would also like to thank Mrs. Carol Helms for the long hours of sitting in a boiler room, cutting papers, and help with computer problems are a few things she does.
- The last person I would like to thank is my homeroom teacher for all of those long hours in the computer lab.
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