Improved Biomass Cooking Stoves

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

Andrew C. Parker, October 2011

Lion Cub Stove
A variation on Larry Winiarski's 16 Brick Stove
and Crispin Pemberton-Pigott's Lion Stove

"I had been waiting all Summer to use my brother's StoveTek
stove to do some experiments. While searching a reference

Here is a report on the recent micro gasifier camp in Honduras from Timothy Longwell

Hugh McLaughlin, September, 2011

I may have solved a design issue with the combustion of the wood gas in a TLUD. I call it the "Toucan Flair", which is a play on words (flair > flare) because the distinguishing feature is an axial tube providing "axial air" to the secondary combustion zone. This axial air source is coupled to the primary air source, which is controlled by a small fan pressurizing a plenum to support the two burners provided for the entire stove.

Additional "scroll air" enters in the riser above the ignition level for the wood gas, providing a concentrated region of combustion. Depending on how much wood gas is generated, as controlled by the degree of fan assist, the flames can be driven to the bottom of the pot, but the unit can also simmer as required (see photos).

This geometry basically turns the concentrator disk inside out - and make for a preheated expanding jet of wood gas, that is consumed by the excess scroll air. Axial and scroll are burner terms for air injected inside the fuel and provided on the perimeter of the fuel. The terms may well be engineering slang. However, the effect is significant, based on my comparison of the side by side configurations (Toucan Flair versus traditional concentrator disk TLUD).

Paul Olivier, September, 2011

Paul Olivier is working from Vietnam, and had put together a comprehensive pdf article explaining the benefits of using TLUD and other gasifier stoves to avoid cooking smoke and create biochar. Cooking Smoke is a major health problem in both rural and urban areas in Vietnam and many other parts of the world, and improved stoves that can also produce biochar can also help urban and rural people retain nutrients in their soils, and reduce pollution.

For more, please download the pdf: Biomass Gasification and the benefits of Biochar

A energy saving stove and tree seed lecture at the Juhidi Children's Club, "Growing up Green Childrens Camp" Nairobi School Aug. 2011
During this camp, Juhidi Children's Club hosted 314 children from all the 8 provinces in Kenya for five days where they got the opportunity to share and learn about the current environmental conservation and preservation trends. Through this we believe that we helped them to understand the role they can play in their local communities in the conservation of the environment and from this they pledged to be environmental ambassadors who will facilitate countunity of and introduction of good environmental practices from the vast knowledge they got.

There is no doubt that there is a huge need in sensitizing the young generation on the benefits of environmental conservation as well as highlighting the benefits and opportunities available.
the seed-to-ash cycle of renewable energy display table

Q & A session with some of the students

keeping everyones hands warm on a cold nairobi morning

a double boiler making tea.

This presentation is about Social Innovations - design and dissemination this focus on undeserved markets. With examples of Good Stoves design and Biochar.

Jolentho in javanese (a local language in Indonesia) means rounded and bulky, so Jolentho Stove means bulky and rounded stove. We gave it the name because the stove liner is made of round and bulky potteries. Every part of the liner is made from pottery, including the grate.

The liner is divided into 8 parts to simplify production and tranportation. To make a liner, one needs to have pottery making skill. For simplicity, the liner is produced by a professional pottery maker. The users only need to buy, install and cast a sand-cement mixture surround the liner. Although cement are not ressistant to heat (easily crumbles), pottery liner provide protection so that cement can last longer. Properly made, the stove will last for 10 years.

The stove has 3 potholes and a chimney to suit the needs of palm sugar producers in Indonesia. The technology is simple: fuelwood burns above grate. Grate provide air suppy and dispose ash. The enclosed combustion chamber provides improved combustion quality. After heating the pot in hole #1 rom beneath, hot smoke is channeled to pothole #2 and #3. There are baffles in pothole #2 and #3 to maximize heat transfer. Finally, the smoke exits through chimney. Chimney also provide draft that boosts combustion.
The innovations we offer are cost and time efficiency and simplicity in stove making, and. It only takes 1 men, 2 hours and 19.25 USD to make a Jolentho Stove and the stove is ready to use within 3 days. This is much more simpler, compared to a mud stove, which requires 4 men, 16 USD and 3 days only to make mud stove and additionally 17 days to get mud stove ready to cook. By all means, the Jolentho is much more favorable.

Daniel Wald July, 2011

Envirofit's G-3300 Wood Stove

G-3300 Stove with Flexible Pot Skirt

This is a pretty straight-forward, efficient wood cooking stove, with a rest in the front for loading stick wood. It's pretty nice looking, and they've worked with Oak Ridge Natl. Labs to create a durable combustion area.

It's got a couple of neat accessories. The one on the picture above is a flexible pot skirt. Pot skirts do a wonderful job of increasing heating efficiency, but they can be hard to implement because not all cooking pots are the same size. This solves that problem simply, and it looks nice which as we know from user feedback is critical to stove success.

They have a chimney attachment which adds another "burner" to the stove, and helps vent smoke more efficiently.

Spec sheets and manuals are on their web site:
http://www.envirofit.org/cookstoves/g-3300.html

Envirofit's CH-4400 Charcoal Stove

Envirofit Charcoal Stove with Cooking Pot

Apparently this is all the charcoal cooking stove. It is designed to be one of the cleanest burning stoves available. At first, I mistook the tall top part to be a cooking pot, but instead it is part of the stove. According to the instructions, the user needs a combination of charcoal and wood sticks or chips, that are loaded into the bottom of the stove, then the upper part with the pot skirt allows the stove to burn more efficiently. There are attachments for the other version of this charcoal stove that allow for grilling. This one seems more optimized for pots.

Additional information on the Charcoal stove:
http://www.envirofit.org/cookstoves/ch-4400.html