Developing Inexpensive Design for Converting Biogas to Electricity

Group 22Sung Hoon Bae (BME)Daniel Rim (ChBE)Chris Zachara (ChBE)Advisor: Dr. David OwensOwen Graduate School of Management

Bae, Rim, Zachara http://www.bme.vanderbilt.edu/srdesign/2009/group22/ BME 273: Oral Report #2

Problem Statement

Bangladesh Large population/high poverty rate

Population: 162 Million – 7th

GDP (PPP): $1,500 per capita – 153rd

http://upload.wikimedia.org/wikipedia/en/f/f2/Bangladesh_(orthographic_projection).svghttp://en.wikipedia.org/wiki/File:Flag_of_Bangladesh.svg

Problem Statement

Only 30% electricity distribution (2002) 25% in urban and 10% in rural (2000) 79% of population in rural (1999)

Government efforts 30% to 38% distribution from 2002-2008 Slow progression

Objective

Generate electricity Household scale generator “Reasonable” retail price Sufficient output electricity

LED light

http://www.odec.ca/projects/2007/sidd7g2/Images/appelectricty.gifhttp://image09.webshots.com/9/2/10/75/112721075ZEGbyv_fs.jpghttp://www.ct.gov/opapd/lib/opapd/newsletter-pics/dollar2520squeezed.jpg

Background: Biogas Anaerobic digestion or fermentation Biodegradable materials

Biomass, manure, sewage, and etc. Composition

Methane: 50-70% Carbon dioxide: 30-40% Hydrogen: 5-10% Nitrogen: 1-2%

Application Electricity and heating

Background: Why Biogas?

Clean Fuel 80% less hydrocarbon and 60% less

nitrogen oxides than diesel Negligible concentrated particles or dust

Availability Organic material – virtually unlimited

Animal waste, food waste, and etc. 65% labor force in agriculture in

Bangladesh

Thermoelectrics

Phenomenon: temperature difference creates electric potential or vice versa

Materials: specially doped semiconductors, most commonly made from Bismuth Telluride

Current Uses: portable refrigeration, electronics cooling

Advantages

Less Expensive than Turbine Technology Utilize Low Grade Heat Small Silent Reliable

No moving parts No maintenance

Challenges

TEG Only 10% Energy Efficient Other design aspects will be very

important Significant Heat Gradient Needed

The “cold side” must be cooled Cold side is just cm’s away from heat

source

Light-emitting diode (LED)

120V tungsten incandescent light bulb 60W: 850lm and 14.2lm/W 100W: 1700lm and 17.0lm/W 90% of power emitted as heat

LED Energy efficient Long operating time: up to 50,000hours Current driven: ~20-30mA

Materials: TEG (TEC)

Product Model:CP2,31,06,L1,W4.5 Laird Technology

30mm x 30mm x 4.6mm Qmax = 29.3W (TH=25°C)

Imax = 14.0 A (TH=25°C)

Vmax = 3.5V (TH=25°C)

ΔTmax = 67°C Price = 23.42$ (http://www.mouser.com)

http://lairdtech.thomasnet.com/item/thermoelectric-modules-2/-series-peltier-solid-state-thermoelectric-coolers/pn-4059?&seo=110&bc=100|3001624|3001688|3001251

Materials: LED Product Model:LED5 40-50DG WH

(TheLEDLight.com) Emitted Color: White Luminous Intensity = 6000mcd max at

IA=20mA Beam Angle = 40-50 degrees Continuous forward current = 30mA Forward voltage = 3.0-3.2V Price = 6$/6LEDs

http://www.theledlight.com/5mmwhleds.html

Materials: miscellaneous

Heat sink Wires Resistors Others

Circuit Schematic

R=10Ω

R=10Ω

• Each resistor dissipates ~9mW• Each diode dissipates ~120mW• TEG generates 29.3W

TEG

V ~ 3.5V

Summary of Current Status

Design Brainstorming

Research Materials

High performance Low cost Long durability

Consult Two ME professors

Future Work

Finalize design Start ordering parts by this week (Jan

25-29) Find a place to assemble and test the

prototype

Importance

Provide electricity in rural area with reasonable price for lighting

Prevent wasted resources (biogas) May help with sanitization problem Increase activity time at night Can be distributed to other third world

countries as well

References Department of Economic and Social Affairs Population Division

(2009) (.PDF). World Population Prospects, Table A.1. 2008 revision. United Nations. <http://www.un.org/esa/population/publications/wpp2008/wpp2008_text_tables.pdf>. Retrieved 2009-03-12.

"Bangladesh". <International Monetary Fund. http://www.imf.org/external/pubs/ft/weo/2009/02/weodata/weorept.aspx?sy=2006&ey=2009&scsm=1&ssd=1&sort=country&ds=.&br=1&c=513&s=NGDPD%2CNGDPDPC%2CPPPGDP%2CPPPPC%2CLP&grp=0&a=&pr.x=35&pr.y=9. Retrieved 2009-10-01>.

<http://web.worldbank.org/WBSITE/EXTERNAL/EXTABOUTUS/IDA/0,,contentMDK:21387765~menuPK:3266877~pagePK:51236175~piPK:437394~theSitePK:73154,00.html>.

<http://www.geni.org/globalenergy/library/national_energy_grid/bangladesh/index.shtml>. .

http://www.malmberg.se/module.asp?XModuleId=14085