Vesto

Here is an example (hard to see of course because it is a still taken from a video) of the spinning of the flame caused by the shaped grate at the bottom.
The fire is circular because it is spinning rapidly, though pushed to the side by the way the fuel happened to be sitting. The spin adds turbulence without a fan and assists in keeping the flame away from the combustion chamber wall.
Here is a really cool picture of a Vesto burning walnut shells in TLUD mode.
Finally, here is a photo of a Vesto cutaway showing the inside parts in their correct positons.

Dear Marc and Ron and All interested in air flows

This is a response to questions about air and Marc’s tube.

Here is an old photo of secondary air entering the combustion chamber of a Vesto pushing the flame to the centre. This accomplishes the following:

Keeps the fire away from the wall, reducing the temperature it has to survive (a lot)
Keeps the flame going
Not allowing it to spread to one side away from the smoke on the other side that might otherwise ‘get away’.
Provides turbulent mixing of flame, hot secondary air and smoke
Allows for preheating to a significant degree (250-500 C)

The fire is circular because it is spinning rapidly, though pushed to the side by the way the fuel happened to be sitting. The spin adds turbulence without a fan and assists in keeping the flame away from the combustion chamber wall.

Here is a Vesto burning switchgrass pellets operating as TLUD, showing that there is nothing special about a TLUD in the sense of it having to operate in a particular fashion. The air flow through the fuel is reduced by the fuel and it operates as a TLUD. The secondary air is send across the surface to keep a deck of flame going at the height of the holes. This obviates the need for adding a circular disk at the top to ’keep the flame going’. Adding a ‘concentrator’ as Paul calls it takes more material and moves the fire too far away from the heat of the pyrolysis bed leading to unwanted flame-outs from time to time. A major issue with all pyrolysing TLUD’s. It is simply not necessary. Just keep the fire near the fuel. This also provides additional vertical space for the flame to finish burning before getting to a cold pot surface.

Finally, here is a photo of a Vesto cutaway showing the inside parts in their correct positons.

The primary air controller is the ring with holes in it. When the handle is moved to the side the holes are closed.

from New Dawn Engineering

VestoVesto

The Vesto consists of five main components:

DONALD KEVILUS , May, 2010

DONALD KEVILUS has uploaded a video of his . well, I guess I can call it a titanium micro-Vesto. It is too small to be a 'mini'!

There is a video of Don at

TLUD Vesto Grasifier
Crispin Pemberton-Pigott, New Dawn Engineering, Swaziland, April 2, 2010


Dear Roger and TLUD Fans (the other kind)

Crispin Pemberton-Pigott and Roger Samson, February 2010

Please click Read More for a set of photos showing the construction of a prototype 125 mm diameter Grasifier Stove burning Switchgrass Pellets provided by Roger Samson (REAP-Canada).

Crispin Pemberton-Pigott and Roger Samson, January 2010

GrasifierGrasifier

Roger Samson was here tonight and we made and tested a Grasifier: a Switchgrass burning stove based on the dimensions of the Vesto adapted to make a lower cost pellet burning stove for Haiti.

Power, 2.5 kw
Burn rate 8-10 g/min
Mass 550 g
Fuel load 600 g though it can hold 750

Lighted with two caps of paint thinners
The flame went completely blue (just before the end) then wobbled a lot and went out.
When it went out there was no smoke indicating there were no volatiles left.

Time to fabricate, about 30 minutes.

I see this as a burner that can be attached to the centre of a Haitian charcoal stove to convert it into very clean burning a pellet stove.

Char yield: 25% of the initial dry mass.
Moisture content of the initial fuel, about 7%

Ash: nearly none.

Regards
Crispin

Video Showing Gasification-Combustion Transitions in the Vesto Stove
Crispin Pemberton-Pigott, New Dawn Engineering, Swaziland, June 4, 2007

Big Improvements For Small Cooking Stoves: The Benefits of Heat Recycling
Crispin Pemberton-Pigott, New Dawn Engineering, January 2004

ETHOS CONFERENCE 31 Jan to 1 Feb 2004

These days so much is known about combustion that efficient and nearly complete
combustion can be basically taken for granted, even if the knowledge has not been put into
practice. Combustion geeks now focus to making incremental improvements in the removal
of unwanted combustion products, largely PICs and CO.

Joao's Clay Vesto Stove - Maputo
Crispin Pemberton-Pigott, New Dawn Engineering, Swaziland, May 2006
Joao da Conceicao

Joao's Clay Vesto

Rescooking.co.za is a site for Radical Energy Saving cooking appliances. According to GTZ-HERA more than 4000 solar cookers were sold in South Afrrica over a three year period.

Rescooking also sells the Hotbag brand of retained heat cookers and Vesto high efficiency stoves.

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