Invention saving lives
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Clean Biomass CookstovesJanuary 27, 2018
Dan Lieberman, Intellectual Ventures LabDean Still, Aprovecho Research Center
Global Good Fund - Partnering for Invention
Government, Multilateral NGO and Commercial Sectors
Late stage
Execution
Invention TechnologyDevelopment
ProductDevelopment
Piloting Clinical
and Field trials
Manufacturing Capacity
SalesMarketing
Distribution
Early stage
High risk
Focus on humanitarian impact in developing countries, philanthropic in approach
Target health solutions for countries defined by the World Bank as having low-income economies or LMICs
Team
University of WashingtonClean Cookstoves
• Dean Still• Sam Bentson• Andy McClean
• Jonathan Posner, PhD• John Kramlich, PhD• Garrett Allawatt• Anamol Pundle
• Dan Lieberman, PhD• Michael Barbour• Van Dinh, PhD• David Bell, MD
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Methodology
Use case
Computation
Concepts
Experiment.
Entrainment
MixingDraft
Unvented VentedPM2.5 (mg/min) 1.75 7.15CO (g/min) 0.35 1.45ηthermal (%) 45 45
WHO Intermediate Targets (Tier 4)
Some stove variations and conjectures(with help from Kirk Harris and Mr. Shen)
Rocket Stove Typical Real Time Data
PM spikes each time the stick fuel is advanced into the stove
Inside the combustion chamber:
When smoke is being produced try reducing the amount of wood burning while maintaining a temperature above 609C
Control the Rate of ReactionReduce the Primary Air
Super Insulate
Mixing:Better mixing of wood gas and air within the flame reduces
emissions (forced air)
Natural Draft Mixing
2.25” ID orifice Stationary fan
“Umbrella spokes” cut up flame
Dwell time
Providing the well mixed flame with sufficient time for more complete combustion to occur reduces emissions
Pressure Difference
When the pressure difference between the flame and the secondary air is greatest mixing may be more effective
Vertical and horizontal “TLUD” type combustion chambers seem to operate with some similar characteristics
Horizontal “TLUD” combustion chamber
Batch loaded sticks burn back by themselves
Rocket stove with horizontal “TLUD” combustion chamber
Mixing by fan and orifice. Secondary air is introduced downstream of the orifice.
Preliminary Horizontal “TLUD”/Rocket ResultsStove type/model
Ceramic Hybrid Test 1
Ceramic Hybrid Test 2
Ceramic Hybrid Test 3
Test Conditions Insulated feed tube, tight fuel pack
Wood species Douglas Fir Dimensionally Cut Sticks
IWA Performance Metrics units Value Value Value
High Power Thermal Efficiency % 36.8% 36.4% 37.3%
High Power PM mg/MJd 68.4 47.5 52.4
Indoor Emissions PM mg/min 6.6 5.1 5.8
Tier Tier Tier
High Power Thermal Efficiency 3.1 3.1 3.2
High Power PM 3.7 3.9 3.9
Indoor Emissions PM 3.2 3.4 3.3
Temp-Corrected Time to Boil min 21.0 20.0 19.0
Firepower watts 4,367 4,918 4,936
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Path forward: develop cleaner, scalable, and more affordable rocket stoves
• Evaluating partnerships with stove manufacturers and distributors in specific locations, traditions and cooking behaviors (e.g. India, East Africa)
• Open-innovation approach to our technology development
• Exploring cost offsets with credit or subsidy programs