Developing Inexpensive Design for Converting Biogas to Electricity Group 22 Sung Hoon Bae (BME) Daniel Rim (ChBE) Chris Zachara (ChBE) Advisor: Dr. David Owens Owen Graduate School of Management Bae, Rim, Zachara BME 273: Oral Report #2http://

Problem Statement Bangladesh Large population/high poverty rate Population: 162 Million – 7 th GDP (PPP): $1,500 per capita – 153 rd

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 Slow progression

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

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 Q max = 29.3W (TH=25°C) I max = 14.0 A (TH=25°C) V max = 3.5V (TH=25°C) ΔT max = 67°C Price = 23.42$ ( )

Materials: LED Product Model:LED DG WH (TheLEDLight.com) Emitted Color: White Luminous Intensity = 6000mcd max at I A =20mA Beam Angle = degrees Continuous forward current = 30mA Forward voltage = V Price = 6$/6LEDs

Materials: miscellaneous Heat sink Wires Resistors Others

Circuit Schematic 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 revision. United Nations.. Retrieved "Bangladesh"