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wood2watts: an INSANE rocket stove idear

 
Posts: 66
Location: Rocky Mountains, USA
10
homeschooling woodworking homestead
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Introduction:

This is more of a shower-thought than a proper project.  I am releasing it into the wild so that other hobbyists can play around with the idea as they see fit.

None of this is patented in any way, and all original ideas should be considered open source/ creative commons/ public domain/ etc.

Though it isn’t a requirement, if you try this, I would appreciate it if you tell me about your findings. (Curiosity and all that.)

Explaining the Madness:

Hey folks, this is a picture of a jet engine.

[ cite: explainedstuff.com ]

Well, duh.

And here is a rocket stove.


Also, duh.

But crazy mad scientist question of the day is, what if we combined them??



I think we need a little explanation of what’s going on here.

(1) since a jet engine can’t burn solids like wood, we’ll go ahead and toast that up as normal in a rocket stove.  Also like a normal rocket stove (2) the now gassified output (mainly “wood gas” along with other unburned material such as creosote) continues to burn.  (3) The exhaust from this  spins a set of blades, which turn a shaft (4) before exiting the “stove” as normal.

So far all we’ve really gained over a standard rocket stove is a spinning shaft.  Now comes the magic.  First, we drive a second fan (5) to suck more air in.  This results in an even hotter, faster, and more complete burn.  Finally (6), if we crudely photoshop a DC motor (aka, generator) onto that, we can get useable electricity!  Hurray!


Interesting Bonus:

As more load is applied to the generator, it would slow the turbine, thus decreasing exhaust draft.  With a little bit of electronical smarts, this could be regulated on purpose to extract the maximum amount of energy from the system while maintaining flow.

Furthermore, since the generator can also be run as a motor, the electronics could feed input power so that a proper draft is present during start-up.  No more need to fiddle around with pre-warming and no more accidental back-burns filling the house with smoke.


Advantages:

   1. More oxygen present would combust hydrocarbons even more thoroughly, and faster, than traditional stove.
   2. Cheaper, and likely more efficient, conversion to electricity than TEG devices.
   3. Can probably be made from salvaged materials. (I picture, perhaps, an automotive starter motor as the generator?)


Disadvantages:

   1. Wood burns differently than jet fuel, and designing a decent turbine may take a lot of engineering & experimentation. (Though even this may be more accessible than it sounds as hobby turbine implementations abound online. [ example ])
   2. Certainly more complex than a standard rocket stove.
   3. Contains high heat, combustion gak, and moving parts and therefore will certainly require maintenance of some kind.
   4. No idea what kind of noise this would make.



Final Note:
   FYI, This is a re-post from my projects blog, here.


Well, that's about it.  Have a good day everybody!
 
Posts: 389
Location: Abkhazia · humid subtropical
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Jet fuel can be injected with compressor (pressure needs to be far below that of the inside of the turbine). A rocket stove pretty much has atmospheric pressure… your contraption would blow the fire out of the front.
If the wood was inside a closed chamber that can be pressurized and heated from an outside source… maybe?
 
Posts: 139
Location: Nomadic
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Maybe combining a rocket stove, wood gasifier (pyrolysis), and a jet turbine of some sort might produce lots of power?  I like you’re thinking beyond the box ideas. Keep them coming if so inclined.
Someone with a machine shop could build a great turbine generator I think.
 
gardener
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Maybe an automotive turbo charger? All the mechanics are built in. An air pump to push boosted air into the system. That air impeller could boost the air as well as hold the shaft for the electrical generation pulley.

 
pollinator
Posts: 1085
Location: Victoria BC
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You can't inject air there, as noted it would do bad things..

So what if you sucked air from the exhaust end? Obv. with adequate make-up air supply avail..
 
wayne fajkus
gardener
Posts: 2694
Location: Central Texas zone 8a
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Another concern is would the impellers cause enough resistance to make the stove flow in reverse?

Just throwing stuff out there...i have no background in this stuff
 
master pollinator
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They sort of make what you are proposing, but it is radically different in how it looks and works.

It is called a Liquid Bottom Boiler, and it uses injected air to suspect the fireball off the bottom of the boiler. It is so stupid hot that there is no grates or ash. As the fuel is dumped into the liquid bottom boiler, it is instantly consumed...and this can be any type of fuel after it is initially lit with natural gas. Wood, coal, tires, anything. It is said to burn things that will not even burn, it is so hot.

The ash then rises out the smoke stack, but before it does, it goes through a series of small cyclones, that remove the heavier fines. These get returned to the bottom of the boiler for reburn, and thus the cycles continues again and again until the impuraties are taken out of the smoke.

Obviously these are 5 story behemouths used to make electricity for the grid, and that steam is derived from cooling the sides of the boiler enoiugh to keep the boiler from melting, yet hot enough so as the fuel is placed inside, it is consumed before it hits the bottom since there is no grates.

I have always thought a home based system could be derived, but instead of powering electricity with illegal steam power, a turbine could be placed in the exhaust stream and a generator spun.

 
gardener
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pollinator
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Looks like  a forge design.

 
Jeremy Baker
Posts: 139
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Only 130,000 rpm. Come on that’s too slow poky......but seriously I love these ideas but I’ll leave them to the professional engineers and genius inventors. Some serious forces at play here. Phase changes, etc. And lots of moving parts to keep my digits away from.
 
Posts: 282
Location: Central Texas zone 8a, 800 chill hours 28 blessed inches of rain
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Great thought experiment for sure.  

[editded, after better understanding the intent to generate electricity]

I do like your out of the box thinking.
 
Cob is sand, clay and sometimes straw. This tiny ad is made of cob:
Clean With Cleaners You Can Eat by Raven Ranson
https://permies.com/t/edible-clean
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