Chips and Chunks

In a J tube setup, has anyone tried using wood chips or chunks (thinking no larger than 2 to 3 inches) in place of splits of dimension wood?

Assuming you have a Peter channel for bypass air flow, it should not stall or snuff your fire enough to create smoke or back draft.

Eugene Howard :The problem is getting the air mix just right ! With dimensional pieces the space between the 'sticks' acts as channels/chimneys. This keeps the upper 2/3rds

of the sticks cool -greatly reducing the chances for Smokeback, further as the air passes through the flame front it gains temperature and mixes with the pyrolized wood gases.

Here the 3 '' T''s, increasing Turbulence , freaky high Temperatures and Time ensure the Great efficiency of Our RMHs Combustion!


To date,there have been 100s of thousands, of Stick fed RMHs and a few successful Wood Pellet fed Rockets ! Larger but still formed pieces shaped/ formed Like Brickettes

have been tried with Little Success.

These formed pieces and wood chips / chunks are burned in 'Fluidized bed' furnaces with a great deal of success - This is a more sustainable

version of " Fluidized Bed " coal burning furnaces, one of the further benefits of this last system is its ability to duplicate the 3 ''T''s of a good Rocket System and do it with much

higher Moisture Levels in the wood fuels !

So- 1)air fuel mixes are hard to control with random sized fuels, 2) several types of motor driven Worm-drive wood fuel have been used with frequent failures due to irregularly

shaped pieces -jambing in the 'Worm' 3) There is no good feed back system developed that automatically adjusts to fuel use moment by moment , ( I Think ) This will Greatly

increase the duties and time on the job of the Owner / Operator !

Your ability to think outside the box IS valued here at Permies.com, and any exploration of this subject you want to make will be followed with interest by 100s of your fellows

here at Permies.com. Many myself included will volunteer to give you (mostly ) informed opinions on your efforts !

This is where I strongly suggest that you consider building and using a traditional Rocket Mass Heater RMH, Now for at least one heating season so that you will have a baseline

to compare if you pursue your idea !

I am off looking for a link to a video showing a well thought out worm drive system that was not as successful as the preceding pellet drive system ! For the Crafts ! Big AL

Eugene Howard : I found this at 1st try - I thought It would take days ! ///// See Link Below :

https://www.youtube.com/watch?v=E9JbbzlxBH0&list=PLtIuZ9K-UzcNnCmoKicRLzYQndplSkUuR&index=9

For the Crafts ! Big AL

Allan:

I think you read my mind. Was thinking forward to an automated feed system for longer term, sustained burns up to and including a continuous burn in an equilibrium scenario.

Almost universally, these seem to be used as single charge "batch burn" units, but as I see top load J tube units loaded, I don't see a whole lot of difference in the air passage characteristics of tightly packed splits and a few short chunks of similar sized wood and especially if the unit has a Peter channel.

I'm aware of the automated "fluidized bed" type units, with screw augers feeding chips or pellets into the burn channel, but I can't see how these could be better than a down burning rocket with chunks falling on top of the burning chips at about the same rate as they are being burnt. Instead of the not yet burnt remnant of a foot long split dropping down into the flame, it would be a continuous stream of small chunks dropping in to do the same thing. This would seem to be an alternative to finding ways to make single batches larger (batch boxes, longer or larger splits or sticks, etc.)

I have a large stack of red building brick and a dozen fire bricks and access to more. Curiosity is getting to me. I can see an experimental rocket in my future!

Yes, I have heard of the problems with "chips", at least the type generated by roadside chippers and those that clear for power lines, etc. The culprit seems to be the long stringy branch tips. Even if you could feed those, they are small and that alone will prevent them from (a) drying out, and (b) allowing a decent burn by snuffing air from the feed tube. The fuel chunks I'm thinking of would be closer to the chunks generated by this contraption*:



Generally 2" to 3" sized chunks that could easily be handled by the feed augers off an old pull type feed grinder. Those could handle ear corn so would also handle these wood chunks. Chunks this size may also allow enough air movement through a mass to allow them to dry out so can be handled in bulk. (Think steel mesh sided corn crib).

BTW, a larger type heated area like the greenhouse in your video example is the objective.

* - Redneck engineering at it's finest!!!

Eugene Howard : While definitely a more complicated system to build Gasifiers can Pyrolize both the wood gases and the resulting charcoals and do not care what bio-mass

is being burned, or its shape, tight packed is very acceptable.The question then becomes actually using the Heat energy in a sustainable way. Anyway we do have an entire

Forum just on Gasifiers, also in the Energy category !

A last word or two, there are a boatload of crap videos on u-tube showing ''flaming units of death'' some one was brave/stupid enuf to call a Rocket Heater, Metal is Doomed

and don't use any Portland cement near your Combustion Core ! For the good of the Crafts ! Big AL

To clarify, I have no interest in gasifiers. The reason for that particular video was to point out the wood chunks of the type and size I was thinking of and how they would be made. The chunks would be destined for a rocket heater of some type.

Also, should mention that while I am a newb on rocket heaters, I am getting up to speed as fast as I can. I have read the RMH Book by Ianto Evans and if/when I built a model, it will be "by the book". I agree it would be best to start with the known baseline and branch out from there. No metal.......no portland cement.

Eugene Howard : O.K., no problem, I was slightly confused by the fact that you picked the (Drive all night ) ''Drive on wood'' site that was dedicated to Turning wood into

Wood gas to run various I.nternal C.ombustion E.ngines . This video shows a much more uniform product ( and larger !) than what you get when the Town Highway Dept .

drops off a load that went through their wood chipper.

Basically this increases wood handling, and the amount of babysitting of your rocket, the additional handling equipment would greatly increase the size of the foot print of

your rocket and make semi weekly ash removal a more difficult process !

However, after almost 30 years of ''But, but -we have always done it this way !'' -The last 4-5 years has seen great improvements in Rocket Heaters, I can't wait to see what

comes next ! For the Crafts ! Big AL

Was going back through the Evans book and found the answer to my question about chunks. It was addressed on page 67.......and the answer was YES, you can burn short chunks just fine. As for ash buildup, it would be no more than you would get using the same amount from any other wood source. But operated on a continuous basis, ash would accumulate faster. So.....yes that opens another avenue for tinkering.......a means to remove ash from a rocket heater that is till running. Best method I've ever used was the old coal/wood furnace in the basement of my parents home. You built a fire over a shaker grate. Shake the handle and ashes would drop down into an ash bin to cool and later be scooped out with a shovel. The fire stayed lit and running all winter long.....months on end. The door to the ash bin also housed the damper to control the flow of combustion air into and up through the ash bin. Fire never touched the grates.....it rested on a bed of ashes.....combustion air rose through the ash bed to get to the fire. Anyway, it strikes me that some type of similar arrangement might be possible with a rocket heater......to remove ashes while the thing is still going. Commercial wood boilers have such systems as do some wood stoves and masonry heaters.

As for further advances in rocket stoves, this is an area that intrigues me. The RMH concept appears to be pretty mature........with folks tweaking the edges and making slight mods to suit their needs. But the thing that remains is the rocket core. This seems to be the engine that runs the thing. The little engine that can. The ability to efficiently convert nearly all of the solar energy that is stored in the wood into usable heat. The mass heater downstream of the core is one way of doing it. A stack of barrels for quick radiant heat is another. But what else lurks in the minds of users? How to harvest all that heat energy.

I don't know who invented steam boilers or what they had in mind as an end use when the did, but I doubt they had any clue about all the creative uses people have found for it. Everything from steam heating systems, to power plants to steam engines in ships and locomotives. But the underlying principle is the same.......a heat source boiling water into steam. The same might said of the rocket core someday.

I just started burning pellets in mine, but the pellet feeder/burner is just an attachment for my rocket, I prefer to burn wood from the land, saving buying bags of pellets.

I might invest in a wood chipper and try bio/wood-chips in my pellet burner sometime. But the real permaculturists refrain from using burning fuel to create chips, but if you can turn someone else's waste chips into free fuel, then your recycling and turning garbage into fuel, but if I were to buy a chipper, that would be burning fuel to create fuel, which is not enviromentally efficient or eceonomical in the end, according to some...

At the end of the day, it can surely be done. I personally can burn pellets, I can burn wood, bio-debris, and I could probably burn wood chips also if I tried.