ETHOS Conference, 2014 Performance Evaluation of Biomass Cookstoves: Bureau of Indian Standard (BIS) Vs. WBT 4.2.2 Rajendra Prasad * Ratnesh Tiwari, Amit Ranjan Verma, Risha Mal, V.K. Vijay Centre for Rural Development and Technology Indian Institute of Technology Delhi(India) * Corresponding author: Cell: +91 9810742111, Email: rprasadiitd@gmail.com January 24-26, 2014

BIS Protocol BIS basically the cold start high power phase of WBT 4.2.2 Fuel size for domestic stoves about 3 cm x 3 cm and 4 cm x 4cm for community stoves , length equal to about half the diameter of the combustion chamber of the stove Moisture content of fuel 5 (±1) % Each test-1 hour duration Fuel burning rate- determined before testing Test setup similar to EPA-5G method with some modifications to meet the requirements of Indian situation Test Fuel fed in 10 equal batches during one hour duration of testing Calorific value of fuel determined with the help of digital bomb calorimeter

BIS Protocol Hood– Duct Velocity- Surface Temperature(body, handle) not more than 60°C Opening adjusted so that no smoke escapes from front Width 1.0 meter, Height 2.34 meter from the base of the hood where stove placed for testing Hood to collect all the emissions from the stoves Appropriate duct velocity fixed as per the size of cook stove and burning rate to maintain the required ratio of dilution air less than 150 kg per kg of fuel consumed The speed is controlled by a frequency variable drive (VFD)

BIS Protocol Thermal Efficiency- Emissions- CO ,CO2 & O2 Measurement- TPM Measurement Protocols- mainly cold and hot start high power phase of WBT 4.2.2 The size of the vessel and the quantity of water to be taken based upon the burning rate of the Cook-stove Temperature of water in pot placed on cook-stove to reach around 95°C and then replaced by a fresh pot of water at room temperature Lid placed on the pot Non destructive infra red (NDIR) technique for CO&CO2 Magneto-pneumatic analysis method for O2 Gravimetric method using Glass micro fibre filter,GF/A 47 mm dia Advanced true Iso-kinetic stack sampler based on USEPA methodologies (EPA Method 17)

BIS Standards

WBT 4.2.2 Protocol Consists of three phases- ◦ Cold-start high-power phase ◦ Hot-start high-power phase ◦ Simmer phase

WBT 4.2.2 Protocol Fuel between 1.5 cm x 1.5 cm to 3 cm x 3 cm One bundles of fuel of 5 kg for each phase of WBT Pot capacity 7 litre, 5 litre water for each phase of the WBT, Pot capacity 3.5-liter, 2.5 liters water for each phase Tests all stoves with similar vessel size and with similar amount of water leaving the burning rate to the operator of the stove to decide based on experience Lid-not placed on the pot Local Boiling Temperature- For a given altitude h (in meters), the boiling point(Tb) of water is: Tb= (100- h/300) °C

IWA Performance Tiers

BIS VS WBT 4.2.2 BIS- Cold and hot start high power phase in a continuous manner, no break in between. -No simmer phase – simmer phase in WBT 4.2.2 largely works on the residual heat(charcoal left) in the stove. A good design of stove should not leave much of charcoal in the stove after main (high power) phase of cooking. -Does not subtract the heat value left in Charcoal from the heat value of the total fuel consumed in calculating the thermal efficiency Emissions measurement in BIS similar to WBT 4.2.2

BIS VS WBT 4.2.2 Hood opening is not defined in WBT 4.2.2, BIS does. EPA 5G recommends “Adjust the distance between the top of the wood heater stack exhaust and the dilution tunnel hood so that the dilution tunnel induced draft is less than 1.25 Pa (0.005 in. H2O)” Maximum velocity allowable on the face of hood V2  1.25 = ½ χ 1.2 V22 or  V2= 1.44 m/s 

BIS VS WBT 4.2.2 EPA 5G recommends – “Adjust the damper or similar device on the blower inlet until the velocity indicated by the pitot is approximately 220 m/min (720 ft/min)”- this means a velocity of about 4 m/s – “In order to ensure measurable particulate mass catch, it is recommended that the ratio of the average mass flow rate in the dilution tunnel to the average fuel burn rate be less than 150:1” -Steel duct, 0.15 m (0.5 ft) in diameter shall be used for the sampling section At 4 m/s, in a duct of 0.15 m, flow would be about 254 m3/hr. For 1 kg of fuel burnt in 1 hour, which is the case with several stoves, there is a contradiction between velocity and dilution rate. WBT 4.2.2 has not resolved it, BIS has done it by adjusting the velocity depending upon the burning rate of the stove

BIS VS WBT 4.2.2 BIS measures the total particulate matter(TPM) while WBT 4.2.2 measures only PM2.5 which is a component of TPM. BIS, before testing a stove and to determine the size of the vessel as well as the amount of water to be taken for testing, the burning rate of the stove is determined. WBT 4.2.2 does not do it, tests all stoves with the same vessel and with the same amount of water leaving the burning rate to the operator of the stove to decide based on his experience BIS, fuel moisture kept at 5(±1)%. WBT 4.2.2 uses fuel with 15-20% moisture BIS- lid is used on pot, WBT 4.2.2- no lid on pot

The setup at IIT Delhi

Experimental Results Efficiency-

Experimental Results Emissions- CO & PM

References EPA(5 G Method),Determination of particulate matter emissions from wood heaters (dilution tunnel sampling location),pp 515-549. Sep 16, 1997, http://www.epa.gov/ttn/emc/promgate/m-05g.pdf Bureau of Indian Standards, New Delhi, India, on Portable Solid Biomass Cookstove(Chulha)-First Revision, IS 13152(Part-1):1991,ICS 97.040.20, http://www.bis.org.in/sf/med/MED04_1157C.pdf Water Boiling Test Version 4.2.2,http://www.cleancookstoves.org/blog/new- version-of-the-water-boiling-test-released-at-ethos-conference.html (2013)

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