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Sedimentary Based Microbial Fuel Cells Evaluated by Power DensityZachary GilstrapAlston LoperMatthew Wieters
Problem SpecificsTo design and implement a sediment based microbial fuel. $20 budget Produce 1Watt/m3 of power
Definition of ProblemSpecifics(1) C6H12O6 + 6H20 6CO2+24H++24e-
The oxidation or loss of electrons
(2) 24e- + 24H+ 12H2O The reduction of gain of electrons
Overall ReactionC6H12O6 + 6O2 6CO2 + 6H2O
Aerobic Respiration
Definition of ProblemSpecifics
V=IR Ohm’s Law
P=IV Power Equation
Power Density=P/V Power Density Equation
GoalsProcess Compatibility with environment Aerobic environment for cathode
Structural General well being Wiring connectivity Stability
Mechanical Simplistic design
ConstraintsEquipment 75% of design from natural or recycled resources
Budget $20 limit for the total amount of materials used in design
Skills Not particularly efficient engineers
Time Two lab periods for fabrication and implementation
ConsiderationsSafety Weather Tools
Ethical Requisitioning resources Impact on location population
Environmental Cold weather, less prolific bacteria
Life cycle/Use/Sustainability Long-term functionality Not recommended for professional use Sustainable
MFC Overview
Relevant Designs• Sediment MFC easily
modified to fit the design goal.
• Mirrored our structural design off sediment MFC shown with slight modifications
• Simplistic design required very little mechanical aspect
Relevant Designs• Larger surface area to
volume ratio was decided to be beneficial
• Referenced design achieved 3300Watts/m3 using 100mL anode volume
• Modifying this principle and aforementioned structural design, we fabricated our own MFC
Analysis of DesignSimplistic design
Easily implemented Modified for design goal
Larger SA:V principle Crushed graphite anode Smaller anode volume
Synthesis of DesignCrushed graphite had an experimentally observed density of 0.365g/mL
Anode volume chosen to be 5g or 13.68mL
Synthesis of DesignUsing this and a simplistic ratio with our second source and a chosen anode volume of 13.68cm3, the wattage produced would hypothetically be .45watts/13.68cm3 for our MFC Article design more efficient*
Materials and CostMaterials: Costs2ft Bamboo N/A 5ft Copper Wire $3.2910g Crushed Graphite (5g anode & cathode) $5.38Window Screen 2.5in x 2.5in (2) $1.76Electric Tape $0.85ZipLoc Bag $0.09
Total $11.37
Description of Design 2ft bamboo
structural support Crushed graphite
anode and cathode Free floating
cathode Anode buried 3in
within the sediment Copper wiring
Description of AlternativesBamboo could have been replaced with PVC Additional cost and environmental impact
Light blue thread could have been replaced with purple thread Stylistic
Potentiometer chosen over bread board Potential convenience
4.00E-05 5.00E-05 6.00E-05 7.00E-05 8.00E-05 9.00E-05 1.00E-040
0.050.1
0.150.2
0.250.3
f(x) = − 4138.1527928818 x + 0.451781674843524R² = 0.950994259408842
Polarization Curve
Current (I) [A]
Vol
tage
(V
) [V
]
Initial Polarization CurveResistance (R)[Ω] Voltage (V) [V] Current (I) [A]
2.8 0.00 0.00E+00300 0.00 0.00E+00660 0.06 9.09E-052090 0.16 7.66E-053650 0.21 5.75E-054820 0.24 4.98E-05
Initial Power Curve
4.00E-05 5.00E-05 6.00E-05 7.00E-05 8.00E-05 9.00E-05 1.00E-040.00E+002.00E-064.00E-066.00E-068.00E-061.00E-051.20E-051.40E-05
Initial Power Curve
Current (I) [A]Pow
er (
P) [
wat
ts]
Resistance (R) [Ω] Voltage (V) [V] Current (I) [A] Power (P) [watts]2.8 0 0.00E+00 0.00E+00660 0.06 9.09E-05 5.45E-062090 0.16 7.66E-05 1.22E-053650 0.21 5.75E-05 1.21E-054820 0.24 4.98E-05 1.20E-05
Final Polarization Curve
2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 1.40E-040
0.050.1
0.150.2
0.25f(x) = − 2148.65878861686 x + 0.330746448997114R² = 0.991652938552688
Final Polarization Curve
Current (I) [A]Vol
tage
(V
) [V
]
Resistance (R) [Ω] Voltage (V) [V] Current (I) [A]4.2 0 0635 0.075 1.18E-041700 0.145 8.53E-052600 0.186 7.15E-053800 0.212 5.58E-054900 0.226 4.61E-05
Final Power CurveResistance (R) [Ω] Voltage (V) [V] Current (I) [A] Power (P) [watts]
4.2 0 0 0635 0.075 1.18E-04 8.86E-061700 0.145 8.53E-05 1.24E-052600 0.186 7.15E-05 1.33E-053800 0.212 5.58E-05 1.18E-054900 0.226 4.61E-05 1.04E-05
0.00E+00 5.00E-05 1.00E-04 1.50E-040.00E+002.00E-064.00E-066.00E-068.00E-061.00E-051.20E-051.40E-05
Final Power Curve
Current (I) [A]
Pow
er (
P) [
wat
ts]
Power Density vs TimeTime [days] Voltage [mV] Power (watts) Voltage (V) [V] Current (I) [A] Power Density [watts/m3]
1 280 1.89E-05 0.28 6.76E-05 1.382 320 2.47E-05 0.32 7.73E-05 1.813 252 1.53E-05 0.252 6.09E-05 1.124 240 1.39E-05 0.24 5.80E-05 1.025 210 1.07E-05 0.21 5.07E-05 0.786 251 1.52E-05 0.251 6.06E-05 1.117 120 3.48E-06 0.12 2.90E-05 0.258 314 2.38E-05 0.314 7.58E-05 1.749 116 3.25E-06 0.116 2.80E-05 0.2410 289 2.02E-05 0.289 6.98E-05 1.4711 220 1.17E-05 0.22 5.31E-05 0.85
Volume [cm3] Volume [m3] Resistance (R) [Ω]13.68 0.00001368 4140
Constants
Conclusions
1 2 3 4 5 6 7 8 9 10 110.00
0.50
1.00
1.50
2.00
Power Density vs Time
Time [days]Pow
er D
ensi
ty [
wat
ts/m
3]
Sediment MFC design successfully achieved an average power density of 1.07 watts/m3
Appendices
Appendices
Appendices
Literature Cited
http://www.nature.com/nrmicro/journal/v4/n7/fig_tab/nrmicro1442_F3.html
http://www.ncbi.nlm.nih.gov/pubmed/24956566