[Stoves] This is not a TLUD stove.

Sun Mar 6 14:14:14 CST 2022

Dear Andrew

I think it is pulling air down the outside and drafting gas up the centre.  The pyrolysation of the inner fuel is fed by air coming through the fuel.  The draft is supplied by the low density flame.

It sounds good. Does it burn to completion? How does the "activity" change as the fuel disappears?

Interesting work.
Crispin

From: Stoves <stoves-bounces at lists.bioenergylists.org> On Behalf Of A J
Sent: Sunday, March 06, 2022 12:21
To: stoves at lists.bioenergylists.org
Subject: Re: [Stoves] This is not a TLUD stove.

I've been working with a new stove design that is showing a lot of promise to char a load of wood.

The stove has no primary air holes in the Fuel chamber.

A  3 1/2" metal screen cylinder is placed in the center of the fuel chamber (16 quart bucket with a lid with a 4" exhaust hole)   Wood Pellets are added around the screen and filled to the top, just below the air inlets.  The screen leaves an open hole in the fuel chamber from the top to the bottom.

I then added soil on top of the fuel Pellets.  I packed it about an inch deep next to the screen and kept adding the soil over the top of the pellets, but left a 1" ring of exposed pellets next to the fuel chamber walls.  This "ring" supplies the primary air.

I add 1/4 cup of gasoline into the bottom of the screen, then ignite the gas.

The flame starts the pellets burning at the bottom.  As the oxygen becomes depleted the flame works itself up the screen to the top of the fuel bed.  Once the flame reaches the top it only wood gas is burning.  The secondary air is supplied through the two vortex vents on the sides of the fuel chamber.  The soil on top prevents the flames from burning the top of the fuel load.  The lid is now installed.

I'm not 100% certain how exactly the "flame front" works in this stove, but it is somehow not burning from the top down, but from the inside out. Most likely bottom up and inside out at the same time.

Near the end of the burn coals will appear on the outer ring of exposed pellets.  They have not started on fire during that process, yet.  I expect they could and that would be beneficial.

So far, I've been able to char 95% of the wood and the total fuel volume reduces about 55%.  The undercharred pieces remain at the outer edges.

This video is from the end of the burn.  You can see glowing embers appearing on the outer ring.

https://youtu.be/3xSp3RfIzxU

I believe this design has a ton of potential to be very cheap and easy to make.  It's not perfect yet, but it is worth taking a look at.

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