Triple walled downdraft wood gassifier 97% efficient

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zelph
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Triple walled downdraft wood gassifier 97% efficient

Postby zelph » Sat Sep 13, 2008 8:16 pm

:D I'm just kidding about the 97% efficiency ;)

Downdraft Woodgassifier Stove tripple walled high efficient wood burner. ;)

I'm going all out on this one. I expect 97 percent efficiency. All calculations have bee scientifically made (got most of it from reading on the net)(forum members here and Backpackinglight, HikingHeadquarters, Whiteblaze. Zen Stoves, the whole gamut. All their info rolled into one stove.

I went one step further to get the efficiency up. I super insulated the secondary air supply so that the air going into the center chamber is as hot as the air inside the main burn chamber. Makes sense right, we don't want cold air going in there according to designers that have given us the details. Once the main chamber wall is heated to it's max the air in the secondary chamber will be heated accordingly. It has plenty of time to get heated as it travels the 4 inches up to the top of the can.

When I fire up this stove I expect one load of dry wood will boil 1 gallon of water. I think that's what the Garlington stove does. It's what he said. This one will do the same only difference is that it will only require 3 minuites to do so. I'm speculating, based on everones input to building this type of stove.

This stove is made of a quart can and a pint can. It's wrapped with 1/8 fiberglass exhaust wrap that is 4 inches wide. The wrap is 1 inch thick around the stove to retain all heat produced by the stove, directing it to thesecondary air supply that seems to be so important to the efficiency of thi type of stove. I hear often that's what is said about the BushBuddy wood burner. So the insulation should increase efficiency to 97 percent(speculation) ;)

Stove has 3 point suspension for a thin walled aluminum Fosters pot. Plenty of room around the pot for heat to rise directly under the pot without restricting flow gasses from the gassification of the wood. Gassification occuring because of the double wall, right?

I'm going to do 3 test burns with stove as you see it. Weigh and provide wood as I did in the Modified Zzip experiment. I will then disassemble the stove down to only the central burn chamber and do 3 test burns.

What will be the outcome? Anybody want to take a guess at the answer? Want to speculate. All you lurkers out there are encouraged to register and give us some of your input. Registered members are also encouraged to make their first post to this thread. See if you can guess at the outcome of the tests.

Question, should I use a windscreen around the pot to retain heat?

Tests will be conducted under calm conditions in my greenhouse. (same as the Zzip tests)

All photos are clickable for enlargement.

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http://www.woodgaz-stove.com/

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DarenN
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby DarenN » Sat Sep 13, 2008 8:28 pm

i'm having a little trouble seeing how this is going to be so efficient. you have holes in the bottom of the fuel chamber and holes around the bottom of the liner, so how is this any different than an insulated updraft stove? please master, teach me. :mrgreen:

Daren.....
"I'd rather be happy than right." Slartibartfast

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zelph
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby zelph » Sat Sep 13, 2008 8:32 pm

DarenN wrote:i'm having a little trouble seeing how this is going to be so efficient. you have holes in the bottom of the fuel chamber and holes around the bottom of the liner, so how is this any different than an insulated updraft stove? please master, teach me. :mrgreen:

Daren.....


It's Suuupppper Insulated, all heat transfered back to the secondary air :ugeek:
http://www.woodgaz-stove.com/

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DarenN
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby DarenN » Sat Sep 13, 2008 8:53 pm

zelph wrote:
DarenN wrote:i'm having a little trouble seeing how this is going to be so efficient. you have holes in the bottom of the fuel chamber and holes around the bottom of the liner, so how is this any different than an insulated updraft stove? please master, teach me. :mrgreen:

Daren.....


It's Suuupppper Insulated, all heat transfered back to the secondary air :ugeek:


it looks to me like it's just going to draw fresh air straight in under the insulation.
i think what is needed is for combustion air to enter at the top of the air chamber and travel down the outside of the fuel chamber and enter the fuel chamber at the bottom. (i'll see your :ugeek: and raise you :ugeek: :ugeek: ) :mrgreen:

Daren.......
"I'd rather be happy than right." Slartibartfast

oops56
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby oops56 » Sat Sep 13, 2008 9:02 pm

So now we got to mess with our wood stoves i lost two days of work outside of rain . Ok this rocket stove made last year stay out side its all wet the pearl lite insulation must be good and wet i think before i fire it up build a fire under it first to dry it out.

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zelph
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby zelph » Sun Sep 14, 2008 12:02 pm

it looks to me like it's just going to draw fresh air straight in under the insulation.
i think what is needed is for combustion air to enter at the top of the air chamber and travel down the outside of the fuel chamber and enter the fuel chamber at the bottom. (i'll see your and raise you )

Daren.......

Oboy!!!!!!that'l work also. The more time the air spends inside the stove the more heat it will absorb and be the better for when it goes up the secondary wall and enters the primary chamber. Good thought fellow uber geek :mrgreen:

Oops has the right idea to have the pearlite as insulation. Oops, don't get side tract like I do :mrgreen: There are some folks on the Backpackinglight.com make your own gear forum that are really into woodburning stoves. I'm going to do this testing for their benefit and also mine :mrgreen:

I always say: "Nothing Ventured Nothing Gained"
http://www.woodgaz-stove.com/

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DarenN
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby DarenN » Sun Sep 14, 2008 12:46 pm

i poked a bunch of holes in a couple of cans last night. might get around to it today, but i'm working on turning parts for a canister stove.

Daren...........
"I'd rather be happy than right." Slartibartfast

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zelph
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby zelph » Sun Sep 14, 2008 8:17 pm

DarenN wrote:i poked a bunch of holes in a couple of cans last night. might get around to it today, but i'm working on turning parts for a canister stove.

Daren...........


No stove time for me today :cry: Was only able to do some reading for you to find the hole size for alcohol :mrgreen:
http://www.woodgaz-stove.com/

Tony
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby Tony » Mon Sep 15, 2008 2:35 am

Hi Zelph,

I'm going all out on this one. I expect 97 percent efficiency. All calculations have bee scientifically made (got most of it from reading on the net)(forum members here and Backpackinglight, HikingHeadquarters, Whiteblaze. Zen Stoves, the whole gamut. All their info rolled into one stove.


If you could get 97% efficiency from this stove the flue gasses coming out the top would be nearly the same temperature as the air going in. :P :P

Tony

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zelph
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Re: Triple walled downdraft wood gassifier 97% efficient

Postby zelph » Mon Sep 15, 2008 11:24 am

Tony wrote:Hi Zelph,

I'm going all out on this one. I expect 97 percent efficiency. All calculations have bee scientifically made (got most of it from reading on the net)(forum members here and Backpackinglight, HikingHeadquarters, Whiteblaze. Zen Stoves, the whole gamut. All their info rolled into one stove.


If you could get 97% efficiency from this stove the flue gasses coming out the top would be nearly the same temperature as the air going in. :P :P

Tony


Hi Tony, I should be able to use a plastic windscreen/heat reflector in close proximity to the pot on this one.
:mrgreen:

The weather here is going to clear up today and the next few days will be sunny to get rid of some of the humidity. I'm gathering my fuel and begining to gather parts together to measure temperature during the test. Getting an area ready in the green house beneath one of the exhaust fans. I'm going to have some fire fun. :D
http://www.woodgaz-stove.com/


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