Predicting in situ sediment fuel cell potential

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Predicting in situ sediment fuel cell potential
0.7 v 10-100mW/m2
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Gear for field data collection
Small fuel cells
original
anaerobic microbial chamber to determine bacterial
densities in sediment
improved
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Intersection of 3 programs
Naval Facilities-sponsored turtle survey

• ILIR sediment fuel cell potential
• use a quick probe to check impact of
• sediment carbon and grain size
• temperature
• oxygen
• initial bacteria populations

ONR-sponsored fuel cell design
acoustically-tagged green sea turtle
short-term effects
Useful application SSC/NRL fuel cell
long-term effects, anode design
8 m2 anode powers hydrophone for 4 months

• ILIR study results
• important environmental parameters
• mapping sediment potential

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Rich organic carbon and grain size dataset from
previous environmental studies
Total organic carbon
Fine sediments (clays and siltslt62um)
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We can combine environmental factors to predict
fuel cell power
Power density-0.89 ln(cm2)15 (based on 3 fuel
cells at TOC2 and 19oC)
Power density0.65 (temp)-6.5 (based on 8 m2
anode and TOC2)
Power density4.6 ln(TOC)13.8 (based on 2.6 cm2
probe at 20 oC)
Ask me about this inflection!
Use historical mean - 95 water temperature
data, multiply power density by 0.89, 1.4, 0.43
Use all field data, calculate power density
Assume 1 m2 anode, multiply power density by 0.43
Sediment power maps
Generic instrument (e.g. satellite transmitter)
duty cycle
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Predicted sediment fuel cell power density with 1
m2 anode over 2009 water temperature range
at 14.3 o C (lower 2.5)
at 18.9 o C (mean)
at 23.7 o C (upper 95.5)
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Time to charge for a typical 10 minute, 240 byte,
1.5 W Orbcom satellite transmission, assuming 60
voltage step-up efficiency and water temperature
of 18.9 oC