[Stoves] Help with rocket stove for Cameroon

[Huck Rorick]

These comments are interesting.  However, I seem to have missed the
beginning of this conversation (I'm looking at Stove Digest issues 7 and 8).

I'd love to see some diagrams of the stoves you are discussing.  Or links to
sites that discuss them.

In thinking about rocket stoves it had occurred to me that having a separate
air inlet, rather than a raised grate that lets air in at the fuel magazine,
could be useful.

It also occurred to me that it might be useful to have a door on the fuel
magazine (as well as the air inlet) to give greater control over inlet air.

Some people I think used sloped magazines to "automatically" feed in fuel.

It seems like one might be able to incorporate some of the features of old
fashioned U.S. wood stoves (which were expensive and cast iron) that were
very convenient, flexible in use (ovens, multiple burners), had chimneys to
take smoke outside and didn't get any smoke in the room when starting the
fire, and started easily, and didn't require a huge amount of tending.

Or some of the features of airtight wood heaters.

 

Huck

 

From: Crispin Pemberton-Pigott [mailto:crispinpigott at outlook.com] 
Sent: Monday, October 6, 2014 12:43 PM
To: 'Discussion of biomass cooking stoves'
Subject: Re: [Stoves] Help with rocket stove for Cameroon

 

Oh:I wasn't talking about sending a stove anywhere. Just mentioning a major
upgrade for anything that has side fed sticks and a firs on the floor.

 

I think the advance is fundamental and can be applied to almost all Asian
stoves. I had a couple of grates made, one from cast iron and another couple
from re-bar. The round rebar were the best - something to do with the curve
and bar spacing but not clear what the full details are.

 

The bar spacing is important - about 4 or 5 mm gap and 12mm bars. Generally
speaking all grates have bars that are too far apart. As a result of the
gaps being large, the char falls through and fails to burn usefully. Jikos
with big holes have the same problem.

 

Regards

Crispin

 

 

 

Thanks Crispin,

but then issue then is getting what ever here. A stove can cost 25.00 and
then it costs 200.00 dollars to ship it here. 

 

Michael

 

 

 

Dear Michael

 

There are a couple of other alternatives in use. One is the grate developed
by the Rocketworx people in Durban. This seems to be very effective at
getting the char burned to ash with very little remnant (means high energy
from available fuel).  The other is the Improved Keren Stove which was
developed at YDD in Indonesia in 2012 that has a tilted grate, very low to
the floor. It is about 20mm high on the near (fuel feed) side and 40mm at
the back. This also has an air entrance at the back about 20 x 40mm
(rectangle). The grate bar spacing is important, as is the shape.

 

This also burns virtually 100% of the fuel put in. The additional
modification to the Keren stove is to lower the pot significantly on the
stove body to serve as an excess air controller. The traditional pot rest
height was FAR too high - about 25mm.  At 7mm it controls the excess air to
a reasonable level.

 

The combination plus one other modification increases the thermal efficiency
from ?16% to ?33%.

 

Regards

Crispin

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