Developing Stoves to Achieve the '50%/90%' Future - Energetics ...

Defining Stove Performance• Hundreds of stove designs have been tested at Aprovecho using thePEMS, resulting in a WBT library. Thanks to Nordica, Karl, Damon!• Lessons Learned: Mixing results in clean combustion (Fan) or forcegas and smoke to enter flame (TLUD).• Increasing heat transfer efficiency is the ‘magic’ that decreases fueluse.• Sam Baldwin and Larry Winiarski describe how to make 50% fuelreduction stoves.• 90% reduction of CO and PM has been achieved in the lab.

50%/90% WBT Benchmarks?•WBT 50%/90% Benchmarks could be created.•Using the WBT library, a 50%/90% reductioncompared to open fire would be:• 50% Fuel Use: 625 g wood or 10.9 MJ energy• 90% reduction Carbon Monoxide: 6.5 g• 90% reduction Particulate Matter: 170mg•Can we go this low in CCT field testing?

WBT Proposed Benchmark: ParticulateMatter EmissionsA cooking stove should emit less than 1500 milligrams (or 170 for a 90% reduction) ofParticulate Matter to complete the WBT.5000450040003500300025002000150010005000PM Emissions vs. BenchmarkSimple Stoves Rocket Stoves Gasifiers Fan Stoves Charcoal Liquid/GasThree Stone FireGhana WoodMud/SawdustBaldwin VITACast Iron Stove from IndiaModified VITA StoveModified VITA w/ Insulation20-L Can Skirted RocketTall Heavy Skirted RocketPrevious ImprovedHeavy Skirted RocketPrevious ImprovedInsulated Brick RocketShort Light RocketTwo-Pot RocketExtra Small Door w/ SkirtCast Iron RocketBaldosa rocket, large body, with1-Door w/out skirt1-Door w/Skirt2-Door w/out skirt2-Door w/SkirtCharcoal-Making gasifierErxperimental GasifierLarge GasifierGrid-Powered FanBattery Powered FanBottom Air Fan StoveWood GasMali CharCharcoal JikoCharcoal Stove with SkirtCharcoal RocketPM Emission To Complete WBT (mg)PropaneAlcoholKerosene90% Reduction = 170 mgNOTE: Only 1 PM measurement for 9 stoves

WBT Proposed Benchmark: CarbonMonoxide EmissionsA cooking stove should emit less than 20 grams (or 6.5 for a 90%reduction) of Carbon Monoxide to complete the WBT.160140120100806040200CO Emission vs. BenchmarkSimple Stoves Rocket Stoves Gasifiers Fan Stoves Charcoal Liquid/GasThree Stone FireGhana WoodMud/SawdustBaldwin VITACast Iron Stove from IndiaModified VITA StoveModified VITA w/ Insulation20-L Can Skirted RocketTall Heavy Skirted RocketPrevious ImprovedHeavy Skirted RocketPrevious ImprovedInsulated Brick RocketShort Light RocketTwo-Pot RocketExtra Small Door w/ SkirtCast Iron RocketBaldosa rocket, large body,1-Door w/out skirt1-Door w/Skirt2-Door w/out skirt2-Door w/SkirtCharcoal-Making gasifierErxperimental GasifierLarge GasifierGrid-Powered FanBattery Powered FanBottom Air Fan StoveWood GasMali CharCharcoal JikoCharcoal Stove with SkirtCharcoal RocketCO Emission to Complete WBT (g)PropaneAlcoholKerosene90% Reduction = 6.5 g

WBT Proposed Benchmark: Chimney StovesA cooking stove with chimney is exempt from the previous standards providedit does not leak. A stove with functioning chimney should use less than 30 MJof energy or 1500 grams of testing wood to complete the WBT.Fuel Use for Stoves with Chimney vs. BenchmarkFuel to Complete WBT (g)30002500200015001000500Sunken Pots Griddle with Holes for Pots Griddle OnlyGood chimney stoves meet the 90% (indoor) emissions reduction!0Sunken Pot withSteam JetsSunken Two-PotInsulativeRocketInsulative TwoPot with HolesOne Pot Rocketwith HolesPatsariPrototypeTwo-pot Rocketwith HolesJustaGriddle Stovewith OvenLarge GriddleStoveA stove with chimney is checked for leaks by placing a HOBO-type CO meter 30 cm above the stove.If less than an average of 50 ppm CO is emitted, the stove is exempt from non-chimney standards

Types of Improved Stoves:1.) Natural Draft Rocket StovesFuels: Sticks, woody biomass,Gathered fuels, some crop residueHigher temperatures, mixing, meteringand then forcing the gases against thebottom, sides of the pot reduces fuel useand emissionsEnvirofit, $25WBTdataTime toBoilFuel UseCOEmissionPMEmission3‐Stone 38 1253 65 2363Rocket 38 650 20 783StoveTec $8-$1251%Reductionwith Skirt70%Reduction67%Reduction

Types of Improved Stoves:2.) Fan StovesTOP LOADINGFuel: Pellets, small piecesPhilips, $60WoodGas, $55Oorja, $25Burning the fuel with forced air jets atthe bottom and/or top of thecombustion chamber creates highvelocity mixing which dramaticallydecreases fuel use & emissions.WBTdataTime toBoilFuel UseCOEmissionPMEmission3‐Stone 38 1253 65 2363Fan 14 614 6 293SIDE FEEDFuel: Sticks, gathered biomass51%Reduction91%Reduction88%ReductionStoveTec/Biolite TEG, $30

Types of Improved Stoves:3.) Semi-GasifiersFuel: pellets, briquettes, somecrop residuesYunnan Gasifier, $45Burning the fuel with carefullycontrolled primary and secondary airwithin a closed stove results in efficientfuel use, and emissions are removedthrough the chimney.WBTdataTime toBoilFuel UseCOEmissionPMEmission3‐Stone 38 1253 65 2363Yunnan 22 734 8 31741%Reduction88%Reduction87%ReductionDaxu Stove, $50

Types of Improved Stoves:4.) Natural Draft Gasifiers (TLUD)Fuels: Pellets, some gathered fuelsChampion Stove, $30Vesto Stove, $60Top lighting, limiting the Primary Air ina TLUD, secondary burn, results in verylow particulate matter emissions.WBTdataTime toBoilFuel UseCOEmissionPMEmission3‐Stone 38 1253 65 2363TLUD 27 737 18 25541%Reduction72%Reduction89%ReductionWorld Stove, $35

Types of Improved Stoves:5.) Institutional StovesFuels: Sticks, woody biomass,Gathered fuels, some crop residueTransferring heat to the bottom andsides of a very large pot efficiently usesthe heat from the fire and emits feweremissions.WBTdataTime toBoilFuel UseCOEmissionPMEmission3‐Stone 38 1253 65 236360L Stove 32 305 7 181(Data Normalized for 5L)76%Reduction89%Reduction92%Reduction

Stove Performance ComparisonTime toBoilFuel UseCOEmissionPM Emission3‐Stone 38 1253 65 2363Rocket 38 650 w/skirt 20 783Fan –Top loaded 14 614 6 293Fan – Side Feed 34 722 6 151Semi‐Gasifier 22 734 8 317TLUD Gasifier 27 737 18 255Institutional 60L 32 305 7 181(Data is from Water Boiling Test)

Knowing which Stove Works:Testing is Essential•LABORATORY• Stoves are carefully designed and optimized in thelaboratory• WBT/Emissions measurements quickly, inexpensivelyhighlight promising technologies•FIELD•Stoves must be re-designed/modifiedwith input from cooks• Consumer testing is at least ½ of stove development• Focus groups must be involved when selecting, comparing,choosing stove models. It does not matter if a stove performswell in the lab if the cooks don’t use it or will not buy it!

Limitations of Testing Targets• There are many more aspects to a stove thanperformance and emission reduction! The stove must bein use, loved by cooks. The ‘competition’ (a three stonefire) is free!• A stove that is not used will not be effective – therefore itis crucial to have consumer approval be an integral partof product development.• TESTING IN THE FIELD becomes more important thanextensive lab testing.• Without consumer approval our new stoves will sit onshelves or become flower pots.• In-field testing is absolutely crucial to also ensure that50%/90% stoves achieve performance and emissiongoals.• Let’s not fail a third time!

Can the WBT Predict In UsePerformance?• A lot of time over the last five years has been spentdebating the WBT and attempting to bring it closer to fieldresults.• Some have adapted WBT to use local pots, local fuel,timing, etc.• Conditions in the field are highly variable so it’s difficult toadequately adjust the WBT. The cook is probably thebiggest variable. Can we bring enough cooks into thelab?• The CCT/KPT in field tests help predict actualperformance.• Use the CCT/w emissions? Cooks use their owntechniques, fuels, foods, compares traditional to newstove. Use hood or nose/mouth emission measurements?

Follow Chapter Five in Sam Baldwin’s Book…• Laboratory, Production, Field, and Market efforts aredetailed in: “Biomass Stoves: Engineering Design,Development, and Dissemination”.1.WBTs and CCTs are used to select promising prototypes2.Templates are developed using local pots, fuels, etc.3.Limited production of small number of stoves made toanalyze costs, methods.4.Stoves are used by local cooks to determine acceptabilityand actual measured performance.5.At the same time, stoves are in stores on a commissionbasis to measure commercial viability.6.On the basis of these tests, modifications are made asneeded and the process is repeated (and repeated) untilsuccess is achieved.

Measuring Emissions:IAP ExposureIn the Aprovecho IAP Meter, a small fan draws a sample through a“snorkel” into the meter, allowing a better measurement of actualexposurePerhaps benchmarks based on exposure could be developed? Measurements ofexposure could be directly related to EPA and WHO guidelines, unlike othermethods.Aprovecho is following up the extensive WBT testing with CCT in Test Kitchen andunder a veranda testing using the IAP Meter.

Measuring Exposure to the CookIndoors and OutEmissions Exposure as Measured by IAP Meter BackpackOutdoors and Indoors for Three-Stone Fire and TLUD14,00012,000PMCO1009080PM (ug/m3)10,0008,0006,0004,000Three-Stone:97% Reductionfrom Indoor to OutTLUD:92% Reductionfrom Indoor to Out706050403020CO (ppm)2,000100Three-Stone Indoor Three-Stone Outdoor TLUD Indoor TLUD Outdoor0

Clean Cook Stoves at Market PriceCarbon credits can reduce the consumer price of new clean stovesMy Uncertain Estimates:(will vary with market, etc)Total Global Warming Potentialgrams CO2 equivalent per liter of water boiled and simmered 30 minutes,normalized for starting temperature and fuel moisture contentCarbon credit income perton per year: ~$5-$10/year5 years?Stove generates 1-4 tonsCO2e savings per yearcalculated CO2 savingsswitching from coal torenewable biomass– about3.8 ton CO2e/yr.Global WarmingPotential (g CO2equivalent/L)7006005004003002001000-100Three StoneFireRocket Fan Gasifier CharcoalPM -- -50*OMPM--680*EC3*CO12*NMHC296*N2O21*MethaneFrom “A Laboratory Comparison of the Global WarmingPotential of Five Major Types of Biomass Cooking Stove”Energy for Sustainable Development, June 2008CO2

Summary• There are promising new generation stoves in existence• The stove community could proceed to multiple-site in-fieldtesting of performance w/emissions, user satisfaction, anddurability.• The stove community could support massmanufacturing/distribution for best quality, lowest price forsuccessful purchased stoves.• There can be millions of stoves ready to address climate changeand health in the near future.• Very clean stoves can be sold at the local market price due to a$5-$10/year carbon credit.NOLS saying as 5 people push a2,000 pound boat up a steepbeach:If we all push easy, it’s hardIf we all push hard, it’s easy.