Predicting in situ sediment fuel cell potential

Lovley Nature Reviews Microbiology 4, 497–508 (July 2006) | doi:10.1038/nrmicro1442

~0.7 v10-100mW/m2

Gear for field data collection:

anaerobic microbial chamber to determinebacterial densities in sediment

Small fuel cellsoriginal

improved

Intersection of 3 programs:

Source NRL OSU MSU

PI Tender Reimers Lewondowsky

Anode MaterialMultiple Thin

Carbon PlatesBraid of Fine

Carbon ThreadsSingle Thick Carbon Plate

Anode LocationBuried in Sediment

In Water of Bottom-Sealed

Chamber

Buried in Sediment

Cathode MaterialBraid of Fine

Carbon ThreadsBraid of Fine

Carbon Threads

Ball of Wound Stainless Steel

Wire

Cathode LocationSuspended by Float in Water

Column

Suspended by Float in Water

Column

Suspended by Float in Water

Column

MFC System

ONR-sponsored fuel cell design

Naval Facilities-sponsored turtle survey

Useful application: SSC/NRL fuel cell

acoustically-tagged green sea turtle

ILIR sediment fuel cell potential

use a quick probe to check impact of:•sediment carbon and grain size•temperature•oxygen•initial bacteria populations

8 m2 anode powers hydrophone for 4 months

long-term effects,anode design

short-term effects

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

Use all field data,calculate power density

Assume 1 m2 anode,multiply power density by0.43

Use historical mean +- 95%water temperature data, multiplypower density by 0.89, 1.4, 0.43

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=2and 19oC)

Power density=0.65 (temp)-6.5(based on 8 m2 anode and TOC=2)

Ask me about this inflection!

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