Predicting in situ sediment fuel cell potential
~0.7 v
10-100mW/m2
Lovley Nature Reviews Microbiology 4, 497–508 (July 2006) | doi:10.1038/nrmicro1442
Gear for field data collection:
Small fuel cells
original
improved
anaerobic microbial chamber to determine
bacterial densities in sediment
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
MFC System
Source
NRL
OSU
MSU
PI
Tender
Reimers
Lewondowsky
Anode Material
Multiple Thin
Carbon Plates
Braid of Fine
Carbon Threads
Single Thick
Carbon Plate
Anode Location
Buried in
Sediment
In Water of
Bottom-Sealed
Chamber
Buried in
Sediment
Cathode Material
Braid of Fine
Carbon Threads
Braid of Fine
Carbon Threads
Ball of Wound
Stainless Steel
Wire
Cathode Location
Suspended by
Float in Water
Column
Suspended by
Float in Water
Column
Suspended by
Float in Water
Column
short-term effects
acoustically-tagged
green sea turtle
Useful application: SSC/NRL fuel cell
long-term effects,
anode design
2
8 m anode powers
hydrophone for 4 months
ILIR study results:
•important environmental parameters
•mapping sediment potential
Rich organic carbon and grain size dataset from
previous environmental studies
Total organic carbon
Fine sediments (clays and silts<62um)
We can combine environmental factors to
predict fuel cell power
Power density=4.6 ln(TOC)+13.8
(based on 2.6 cm2 probe at 20 oC)
Power density=-0.89 ln(cm2)+15
(based on 3 fuel cells at TOC=2
and 19oC)
Power density=0.65 (temp)-6.5
(based on 8 m2 anode and TOC=2)
Assume 1 m2 anode,
multiply power density by
0.43
Use historical mean +- 95%
water temperature data, multiply
power density by 0.89, 1.4, 0.43
Ask me about this inflection!
Use all field data,
calculate power density
Sediment power maps
Generic instrument (e.g. satellite transmitter) duty cycle
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%)
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