[Stoves] Spherical Cow Dung Balls for ND-TLUDs in Bangladesh : Dung is very do-able

Fri Nov 2 20:38:24 CDT 2018

Dear Dung Dippers

On Julien's last point, the Ag Ministry in Tajikistan has been concerned about burning dung instead of putting it on the fields. Because of a near complete loss of tree cover and zero planting, many people who used to heat and cook with wood now use dung which is prepared in thick centered 'pies' a little larger than a dinner plate, 60mm thick, tapering to the edges.

Because of there being no quick solution to the fuel supply issue, the best thing to do is to reduce consumption be changing the stoves.

Because of the poor design of the traditional heating stoves it is widely believed that dung cannot burn on its own so it is invariably mixed with some twigs like cotton stalks or coppiced ‎wood. Many fields are lined with trees trimmed for coppicing.

A technical assistance project assisting Caritas Switzerland took place in early 2016 and resulted in two new stove designs intended to burn dung alone, at a high enough heating and cooking power to match or exceed the standard performance. These two models, initially dubbed Model 1 and Model 2 (there were four more in the set) came in two iterations each: with and without a cooking pot hole.

The traditional way to burn dung is extremely smoky and requires attention about every 15 minutes ‎to add a small amount of fuel.

The two new models adopt the combustion system used on a Mongolian stove known as the MM2 which was an end-lit crossdraft burner with a flame tube between the fire chamber and the heat exchanger.

The TJ2.0 was adapted later to become the much more powerful KG2.5 for use in the mountains where it drops to -30 C.

The fire is ignited at the far end of the fuel chamber directly in front of the flame tube (usually 3" pipe) and the fuel stacked around to and towards the door at the 'front' of the stove. There is a grate.

The door has within it an air controller. There is no other air entrance. This arrangement also has the cooking station on top of the area in which the fire is lit, immediately next to the flame tube entrance. With a good draft from the chimney, the fire is quite intense and as the fuel is burning from the hot zone into the fuel stack, it is a sort of TLUD on its side. Cooking power is admirable, much higher than the traditional stove with mixed fuel.

The fire is indeed very smoky, but all that goes into the fame tube and a substantial fraction of it is combusted inside the pipe. Apart from cooking over the fire, people cook on top of the heat exchanger as the temperature of the plate is over 300 C. It is certainly hot enough to heat a 20 litre container of water.

The end result is a stove which will burn dung alone, or the twig fuel alone if you have it, under conditions controlled enough to limit the excess air and maintain a very hot fire zone no matter what the fuel.

Fuel consumption is down 40-50% de‎pending on the home. They no longer have to buy twig fuel to co-fire, and there is more fertilizer available. The minerals are preserved in that the ash is tossed onto the fields.

All the drawings and many photos are available at www.newdawnengineering.com in the Library, Stoves, [country] and [model]‎.

Regards
Crispin

They are formed by hand and stuck onto a vertical wall to dry. So they are sticky.

Hello Richard;

What do you give a cow with diarrhea?  .... (answer at the end)

Thanks for your advice.  I have visited www.legacyfound.org<https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.legacyfound.org&data=02%7C01%7C%7Ccc76cfb043924cab96c008d6411c5456%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636767987254576473&sdata=8yxyEt%2BTVMgbu2o6a%2BgYee9no5CUUb7wiCGohZfQ6oI%3D&reserved=0> in the past for ideas on making briquettes.

In a past life, I spent at time at the south end of many cows facing north, but I never gave much thought as to what part of manure was sticky.

I would not have expected the fiber to be the sticky part.  If the solutes and fine suspended particles can be removed, and the fiber used as a binder, that would be excellent!   The leachate could be combined with biochar.  Removing nitrogen from the fuel would reduce gaseous losses of N.   I have always been sorry to see good manure fertilizer burned.

.... A lot of room.

Cheers,
Julien.
--
Julien Winter
Cobourg, ON, CANADA

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