Re: Rocket stove design for retort heating #rocketstove #retort

Geoff Thomas

Hi, Kobus and all, this  thread developed around a small user wanting to use wet wood, - True?

The use of a rocket stove was suggested ? and other ideas. 

My take is that the rocket stove is argued to be more efficient to use the second class wood to dry his timber? 

I suggested adding Solar Thermal cheap input air heater, but that was not acceptable to the original enquiree, - fine.

Still throughout this thread is the need to dry the wet wood, although the Rocket stove produces (no/liitle?-) charcoal?

So I thought about an ancient  wood heating stove invented in Australia/NewZealand/Both, - (let’s not encourage WW111 by taking one side or the other of these two great religions..)
over 100 years ago, - the "Da!Dah”  Chip heater. (I have mentioned this item before on earlier threads).

In those days, Australian/New Zealand  folk were breaking out of the English (one bath/year/week) tradition, it being far hotter and far more humid than the ‘mother country’ to a more one bath per day/preference, and wood was much more available, so the ‘Chip heater’ was made specifically to heat the water in one’s bath,  it was  a down draft burner, - I will try to include two PDFs - unfortunately both are part of my then web page, - not being able to find just the Photos - seems as one updates, photos can just go.. but these were Documents I preserved, from the website, and anyway the accompanying rave is helpful, although please everybody understand that I do not manufacture, sell, supply, etc these units anymore as I only organised 2 dozen, - using donated rusted out units and some old moulds, and it took over two years to sell those so my manufacturer pulled the plug on that item.

In the first photo, - from above, one is looking  down the input air Cone, - big enough to feed smaller (hence ‘chip’) items into the bottom of the burner, - the unit itself is a double skin, “bucket in a bucket” the inside bucket is the burn chamber, the outside bucket serves to introduce the water via a funnel from one side, - down a ways, the water then travelling around and under the ‘inside skin’, to a small output pipe on the opposite side, - higher than the input so allowing greater heating of the water, which then dribbled down into the bath, please see associated articles, but recall I do not sell nor make these items, - this is not an advertisement in any way, shape, or form. 
There was also a (4 inch)  chimney taking the combusted gases up through the bathroom roof. 

The importance of the Down draft cone (contracting in size toward the bottom, - so speeding up the air fiercely) can not be emphasised enough, - virtually a blast of air, and the more combustible the material the stronger the blast, - it burnt Everything, - it injected a surplus of oxygen, and any material would burn and the fire at the bottom radiate and convect most of that heat to the surface of the inside bucket, where it would be picked up by the migrating water in the outside space, contained by the outside skin.

So strong the downward blast, virtually no smoke, - as advertised, old boots, telephone directories, floor sweepings, all gone, converted into heat, including all gases derived therefrom, Combusted Completely.

So what has this extravagant machine got to do with modern Biochar,  ( extravagant in that it would suck in more than it could burn and do this “Whuff-Whuff  thing, quite alarming to some, but a fond memory to newly wedds cavorting in their bathroom, - the things people send you on the Internet..

I would think that this is the ultimate machine for heating water from waste, rubbish, wood chips, some wet timber, etc. the hot water, - low pressure, could be easily directed through ‘eg’ an old car radiator, to the input air flow of a wood dryer, - possibly needing  a small computer fan to achieve the necessary throughput, - but possibly not required.

Interestingly this ‘chip heater’ was toward the end of it’s time a project often given to newly educated Plumbers to achieve their final exam, - so no great machinery involved.

I would think still a vibrant possibility to any third world villages without cheap electricity.

I have one, - of course, I used it when living in the rainforest in Kuranda, - heat up 3 buckets of good hot water, - pour over oneself, - wet, wash, rinse, - no electricity required.

Interestingly, I tried to use mine to kill weeds with hot water, unfortunately not really hot enough, but, in reference to Stephen Joseph’s comment on mixing in plastic, by feeding in that white polystyrene packing foam, got it up to boiling temperature at reasonable volume but could not with wood chips.

Whatever, an exotic fuel, and probably becoming a lot less available, but the chip heater, the omnivorous burner, seems an excellent water heater for a drying kiln, - and you can have a good hot bath from it as well!

Hope the two pdf’s come through OK, please feel free to contact me on wind@... for me to send them direct as an attachment.
Note the first rave was the old size, - high enough to go into a bath, - the later smaller one to fit into Australia Post, - could have been very good for camping also, - very little feed back, most people happy, - one couple not happy, too small, would not sell it back for cost price or even more, so it was still worth more to them than the money, - people are funny..

Geoff Thomas 

On 11 Jan 2021, at 6:20 am, Kobus Venter <kobus@...> wrote:

At the end of the famous Bob Wells demo there's a small clip of them using a rocket stove to heat a retort, with the evolved pyrolysis gases - I am guessing ignited by the rocket - to heat a pot. They used a stainless beer keg. Perhaps Bob can explain more, but the advantage of a rocket stove providing the heat from low quality feeder wood is plain to see:



On Wed, Jan 6, 2021 at 6:28 AM Norm Baker <ntbakerphd@...> wrote:

The MC of the feedstock was at 12%. Ambient RH was at 99%.



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