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This presentation was put together by A.Phrao, Chiang Mai of the Warm Heart Foundation in Thailand. They are using biochar to attempt to restore fertility to badly degraded mountain soils, and to intensely fertilized mono-cropped soils that have low fertility.

They designed this medium sized TLUD system with the following constraints:
They wanted to design a simple, low-cost biochar burner that:

  • Can be built from locally available materials, preferably recyclables, at little cost;
  • Can be manufactured by local mechanics without
  • training;
  • Can be operated safely and efficiently by a single person;
  • Can use a variety of feed stocks, preferably field waste;
  • Can produce a minimum of 1 ton of biochar per week under normal, unpressured operating conditions.

The solution is pretty ingenious - please take a look at the PDF for all of the details.

The following is quoted from the pdf:
The 6-burner TLUD merry-go-round:
materials list

  • • 1 x children’s playground merry-go-round or equivalent
  • • 6 x 200 litre steel drums
  • • 6 x 60 litre steel drums
  • • 8 x meters 1” OD steel pipe
  • • 6 x meters 1” angle iron
  • • 6 x 3” hinges
  • • Miscellaneous nuts and bolts, welding rods, grinding wheels
  • • Circular grinder, arc welder

System

  • • 6 TLUD burners
  • • 55 kg corn cob load/barrel
  • • 20+ kg biochar output/barrel
  • • 120 kg per burn
  • • Single man can load, light, rotate, load, light, rotate…empty, extinguish, empty, extinguish… all six loads in 1.5 hrs.
  • • Single man can grind full load in 1.5 hrs.
  • • Two full loads per day = 240 kg/day
  • • 6 day week = 1,440 kg/wk
  • • Feed stock requirement = 3,600 kg/wk
  • • Cost: corn cob @ 700 baht/ton ($23.35) or $60/ton biochar if farmer does not have own supply

The Urban Household Energy Transition
Energy, Poverty, and the Environment in the Developing World
Douglas F. Barnes, Kerry Krutilla, and William Hyde
March 2004

PREFACE
This book develops a comprehensive assessment of the evolution of
residential fuel choice and consumption in urban areas in the developing world,
and the effect of urban growth on periurban forest resources. The research is basedon an comprehensive analysis of a series of household energy surveys performed under the auspices of the Energy Sector Management Assistance Programme (ESMAP) of the World Bank From 1984-2000, this program produced more than 25,000 household energy surveys in 45 cities spanning 12 countries and 3 continents. Additionally, GIS mapping software was used to compile a data base of site specific vegetation patterns surrounding a sub-sample of 34 cities. Taken together, the energy surveys and the biomass data contained sufficiently wide variation in urban fuel choice and consumption patterns, local resource conditions, and energy policy regimes to enable an assessment of the factors underlying the evolution of urban fuel utilization and forest resources. By comparing the patterns of energy use of a large number of cities, we were able to distill a comprehensive picture of both the diversity underlying the energy transition and the fundamental principles applying across cases.

Full report at:
http://www.esmap.org/sites/esmap.org/files/Rpt_UrbanEnergyTransition.pdf

Dale Andreatta, Ph.D., P.E.
November 18, 2013
dandreatta@sealimited.com
Introduction
A series of tests was done to compare the Cajun Rocket Pot (the finned pot) with an ordinary pot of effectively the same size. The finned pot has 70 round fins (pin fins) on the bottom with a diameter of 13 mm and a length of 14 mm. The diameter of the bottom of both the regular and finned pots is 248 mm.

The area of the bottom of the flat pot is 0.04828 m2, and the area of the bottom of the finned pot is 0.0883, or 83% greater. Moreover, the flow is impinging on one side of the fins, which typically gives much better heat transfer than gas flowing parallel to a surface, which is what happens over most of the bottom of a flat bottom pot. It would therefore be expected that the finned pot would have much better heat transfer efficiency.

Both pots were tested on 7 different heating devices, with the fire conditions set up to be as close as possible between pot tests. Only one test was done on each pot. There are a variety of ways to compare the effectiveness of the two pots, and as many ways were used as were meaningful for that stove.

The 7 heating methods were:

  • 1. Natural gas range
  • 2. Propane stove
  • 3. High performance charcoal stove
  • 4. Open fire burning wood
  • 5. Simulated open fire burning natural gas
  • 6. Fan powered stove burning wood
  • 7. Rocket stove burning wood.

The heating methods will be described in more detail in the sections on test results for the individual
stoves.
In general, possible methods for comparing the pots are:

  • 1. Time to boil, corrected to 5000 g of water and 80 degree temperature rise
  • 2. High power efficiency
  • 3. High power heat transfer
  • 4. Low power efficiency
  • 5. Low power heat transfer
  • 6. Overall efficiency (weighted average of high power and low power)
  • 7. Average efficiency (simple average of high power and low power)
  • 8. Total fuel consumed.

There are advantages and disadvantages to each of these methods, and there is no one right way to compare the pots. Some methods are not appropriate to use for some stoves, but in general, results will be given for as many ways as possible to compare the two pots. The reader can decide which is the most valid way of comparing the pots.

File attachments: 

Dear Friends
As of this writing, it was just three hours since I was back from Tacloban City. I took the 13:40 flight of the Air Asia.
The following are the impressions I gathered from the trip. My observations were limited to only the city center from November 23 to 24, 2013 and through a distant observer’s point of view. However, I was not able to capture the anguish, and despair of the aftermath.

wocket stove with wok
wocket stove galvanized interior
wocket stove galvanized finished
wocket stove stainless interior
wocket stove stainless finished

Wocket Stoves

Sustainable Berea wanted me to build them a couple of rocket stoves to be used with woks for stir frying lunch during their local Solar Tour.

I bought a couple of 14” steel woks for cooking and a 14” stainless steel wok and a 13 quart stainless steel bowl for skirts.

I used the stainless bowl with 4“ galvanized steel stovepipe and the stainless wok with 4” stainless steel stovepipe.

I used 4” Tees for combustion chambers, 2x4 metal stud piece for feed chamber and expanded metal for grate and back wall of combustion chamber.

I used 6 gallon metal buckets for the shells.

I put a 1” thick piece of ceramic fiber board under the bottom of each Tee.

I put an 8” stovepipe outside of the galvanized steel riser to reduce overheating and insulated between it and the bucket with fiberglass insulation.

I insulated around the stainless stovepipe with two 1” pieces of ceramic fiber blanket and between the ceramic fiber and the bucket with fiberglass.

We are trying to (a) reduce the amount of emmisisons from charcoal production and (b) Condense and recover as much of the smoke into a usable product for your home/farm. Wood tar - the following is an explanation from the good folks at Food and Agriculture Organization of the United Nations (FAO) about what is going on in this process.
"The non-water component consists of wood tars, both water soluble and insoluble, acetic acid, methanol, acetone and other complex chemicals in small amounts. If left to stand, the proligneous acid separates into two layers comprising the water insoluble tar and a watery layer containing the remaining chemicals. Recovery of the water insoluble tar, often called wood or Stockholm tar, is simple - it is merely decanted from the water phase. This wood tar has uses as a veterinary antiseptic, a preservative for wood, a caulking agent, and as a substitute for road tar" http://www.fao.org/docrep/x5328e/x5328e0d.htm

For more pictures click here

File attachments: 

Notes from Ed:

Hi sorry I havn't been following all of this thread, but I thought this might be of interest to somebody,

I am a market gardener, I produce a steady stream of biochar from my water heating systems. I live in Wales, it is cold and wet here and I like washing in hot water.

I have played with bringing tlud stoves indoors but it is not easy and so I have built water heating systems using what I call biochar rocket stoves (sorry if this brings back bad memories Crispin!)
Because they are not filled, lit and emptied from the top they can easily be left in place under heat exchangers, hot plates and a flue outlet pipe. Here in Wales this is important.
If you run them in the evening, when you most need space heat and cooking, then after a couple of hours you have your biochar. It is fine to keep them burning for as long as you want (whereas there is a limit to how much you can keep topping up a tlud)
Unlike wood burning stoves, it is possible to have the flue outlet angled up about 30 degrees from horizontal and surrounded in a thermal mass to capture residual heat. Otherwise the 8th photo is of a section of flue outlet with integral thermal mass.
Shut a door on the front and the biochar goes out overnight. My CO meter has yet to read 1ppm indoors. Empty the biochar by sliding out the floor of the stove and it drops straight into a metal bucket, no quenching, no dust and no mess.
The first photos are of these stoves connected to a 50 litre water tank + hotplate and oven for cooking. (The pipe in the second picture is to give secondary air to the flames.) The system in these photos is mobile and connected to a small header tank so that I can do demos at permaculture conventions and workshops.
The youtube video link below is of something different; a double walled flue pipe with feed and empty hoppers for putting in biomass and emptying out biochar. A bit like an anila stove except the inner combustion pipe has no floor, it goes straight through to the stove below. If its ok with Crispin, I was thinking of calling this flue pipe an anila flue pipe.

http://youtu.be/MTiSTrdYuoA

Lighting Cone on the Keren Stove no smoke 1 min after lighting
Anglo Supra Nova Stove
Loading the Anglo Supra Nova Stove
Good Fit for Cone Lighting
Lighting Cone on the Anglo Supra Nova
Handles get hot on lighting cones - make them large

Lighting Cones can help make traditional and charcoal stoves light more efficiently and with less smoke than other lighting methods. For the best detail, download the Masters thesis pdf from Kathleen Lask

From Crispin Pemberton-Pigott's Description:

"The main principle is that there should be enough draft to light the fire rapidly. The lighting cone provides this if it is about 500mm tall."

"The second principle is that the bottom of the cone should sort of cover the lighting fuels so that most air is pulled from below, not from the side."

"The third principle is that if there is a secondary air supply at of just below the top of the fuel, the bottom of the cone should bypass it so that the heat inside the cone is not used to pull air through the secondary air ports. Very few stoves have a secondary air controller."

In the result with good fit: "You can just see on the left that it bypasses the secondary and draws all air from below, through the fuel – in this case charcoal. Peter Coughlin reports it reduces the charcoal ignition time by more than ½. We will quantify the smoke reduction and GERES way independently confirm it at some point – it is about 90%."

Lighting stoves can also be used with traditional fires. In tests lighting damp wood in Suba Island "The speed of ignition and reduction in smoke was dramatic. You can just see the hot air distortion of the picture above the cone – basically no smoke. It is quite a bit cleaner than the fire when lit and the cone removed."
The cone on the 3 stone fire is 125

The Stove in the top example is an Anglo Supra Nova.
"It was developed at YDD during the World Bank/Indonesian Clean Stove Initiative."

"It as an Anglo Supra with preheated secondary air. It can burn wood or charcoal, and it can burn wood pellets in TLUD mode. It can automatically switch from pellet burning TLUD pyrolyser mode to char-burning mode by using a disc of paper on top of the grate."

"The loose piece of clay is a door which can close the primary air without affect the secondary air. It provides a significant level of power control without adding or removing fuel. The heat transfer efficiency burning charcoal (it is nominally a charcoal stove) is about 50%. It Is portable with handles and sells retail for about $5.50."

Kathleen’s investigation is attached.

Regards
Crispin

Joshua B. Guinto in the Phillippines used the Oblak Holey Roket stove as inspiration and created a stove with an extra compartment to store char until cooking is done and the char is sufficiently cooled. He has done a wonderful job of writing up the results in the attached pdf.
From his conclusion:
The Charmaking Stove is Born!

  • The Char Making Holey Roket Stove is born!!
  • It allows harvesting bio char safely and conveniently and without having to tip the stove over. It eliminates the risk of heat fatigue, burns and open fires.
  • It allows clean cooking with the similar performance as a gasifier stove.
  • It allows continuous cooking.
  • The stove will last for four years or more.
  • It can be used with many other kinds of fuels.
  • The stove is much cheaper and can be fabricated in village workshops thus promotes social inclusion much better.
  • With clay, the stove has very small ecological footprint.

Marc Pare has a been keeping notes on his attempts to solve the problems of burning rice hulls in household cooking stoves in his rice husk design log: http://ricehusk.cc/goodboiler/

In it, he goes back to the beginning of 'stove'-ness and introduces design and prototyping concepts as well as giving his test results.

Check it out.

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