Mussie T. (Lecturer at Mekelle University, Ethiopia), October, 2011

This is a Natural Draft Gasifier stove, that is designed with a central column of air that is designed to burn more common Ethopian fuels, e.g. coffee husk and saw-dust (cow dung binder) briquettes in addition to more conventional wood chips.

the air column is drilled on the surface so as to let additional primary air radially into the fuel at different stages to compensate for air clotting that can occur when run with small sized fuel as you go up from along fuel column. This helps the flaming pyrolysis from being air starved due to interlocking of fuel particles. In addition to that, closely spaced holes of relatively larger size were made near the top of the central air column to supply more hot post‐pyrolysis secondary air. The presence of two hot secondary air admission points is meant to supply enough air while keeping the stove short with reduced heat loss.

Once the stove has enough fuel, it is typically started with wood chips, or an accelerant to help the briquettes light, and then in all of the trials it burned without smoke until the fuel tank was filled with charcoal (typically between 60 and 90 minutes later). This is a biochar-producing stove, the stove does not efficiently combust it. Friability and the composition of the char depended upon the feedstocks.

For an excellent analysis of the stove, and pictures of the biochar, please see the included Report: Results from Preliminary Experiments Conducted on Multi‐level
Primary Air Entry Gasifier Stove

A couple of the presentations from the ASEAN-US NEXT-GENERATION COOK STOVE WORKSHOP, November 19, 2009.

One is a great study by Dr. Modi of Columbia University of several stoves in Tanzania, and the other is some useful info from Tami Bond. Kirk also gave a very useful presentation, but unfortunately it was not included in the proceedings.

Impact of improved cookstoves on indoor air pollution and adverse health effects among Honduran women
Stuart Conway, Trees, Water and People August 5, 2009

Maggie L. Clark, Jennifer L. Peel, James B. Burch, Tracy L. Nelson,
Matthew M. Robinson, Stuart Conway, Annette M. Bachand and
Stephen J. Reynolds


CO and PM Emissions from TLUD Cookstoves Presentation to 2009 ETHOS Conference, Kirkland, WA 23-25 January 2009 Paul Anderson, Biomass Energy Foundation, January 22, 2009

CO and PM in TLUDCO and PM in TLUD

Introduction Since 2005, high quality quantitative data on emissions from cookstoves have been accumulating. For data to be properly comparative, both a standardized cooking task and reliable emissions measurements are required. The principal test continues to be the standard five-liter Water Boiling Test (WBT), about which much has been written and debated. Equipment for reliable emissions measurements has been gathered, installed, tested, and accepted for operation at the Aprovecho Research Center (ARC) in Cottage Grove, Oregon, USA. No known equivalent site exists anywhere else in the world. Sincere thanks are given to the Shell Foundation, other financial donors, the ARC organization, and the numerous scientists who assisted in the establishment and operation of those emissions hoods. While the ARC facilitated the gathering of data presented here, the author is responsible for interpretations and any errors or omissions. Dozens of different stoves have been tested to various degrees with the ARC equipment and methodologies. Hundreds of separate test results have been collected. The two measured emissions are carbon monoxide (CO) and particulate matter (PM). This report is focused upon those emissions from four categories of cookstoves: 1. The traditional “three-stone fire,” which provides baseline data. 2. “Simple improved cookstoves” that utilize basic combustion that is confined in various stove structures made of ceramics, mud, or metal. 3. “Rocket stoves” that utilize clear principles and designs that provide significant control over the amount of wood in the area of combustion, with some restriction on the flow of air to the combustion area. 4. “TLUD (top-lit updraft) gasifier stoves” that essentially separate in time and location three processes of biomass burning (pyrolysis, char-gasification, and combustion). They also emphasize separate control of primary and secondary air supplies. Robert Flanagan, a TLUD stove developer in China, has coined the term “third-generation cookstoves” for these stoves that have the capability to easily create and save charcoal for use as a “biochar” additive to improve soil fertility (as in “terra preta”) and to remove permanently carbon from the atmosphere. See attached presentation

OSHA CO Factsheet
Occupational Health and Safety Administration, US Department of Labor, 2002

CO warning and measuring for 40$
Frans Peeters, August 27. 2006

CO SensorCO Sensor

Air Pollution and Respiratory Health among Honduran Women (2 MB pdf)poster
M.L. Clark,1 J.L. Peel,1 S. Conway,2 J.B. Burch,3 S.J. Reynolds 1 2006

1Colorado State University, Fort Collins, CO; 2Trees Water & People, Fort Collins, CO; 3University of South Carolina, Columbia, SC



CO/CO2 Ratio in the Charcoal Stoves Tested at Aprovecho (pdf)
Dean Still, Aprovecho Research Center, June 23, 2006

The following graph plots the levels of CO and CO2 during one test each of the charcoal burning rocket stove and Jiko-type charcoal stove from Ghana. A higher level of CO2 suggests a higher burn rate of fuel.

It can be seen that even though the CO level for the rocket drops below 10 ppm, the CO2 level remains high suggesting a high firepower continues. The Ghana charcoal stove has a lower level of CO2 with a considerably higher level of CO.


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