ARC E-Newsletter 9.17.20: A Tier 5 Rocket Stove

[Aprovecho Research Center]

A Tier 5 Rocket Stove

A Tier 5 Rocket Stove Sam Bentson, ARC Lab Manager, and David Evitt, ASAT COO, developed the Jet-Flame with Shengzhou Stove Manufacturer and Dr. Dan Lieberman and Dr. Mike Barbour at the Gates funded Global Health Labs The cast iron Jet-Flame sends 30 jets of pre-heated air up into the burning charcoal and wood in an open fire, sand/clay stove, or in a Rocket stove. It is patterned after industrial burners that position jets of primary air underneath the fuel bed to clean up combustion. Both Underfeed Stokers and Fluidized Bed Boilers use primary air that enters the fuel bed from underneath the fire. In 2013, with DOE funding, ARC built a bottom-air-only prototype stove and has been experimenting with improving the technique, resulting in the Jet-Flame combustion chamber accessory manufactured by SSM in China. There are several advantages in a bottom-air-only approach. The jets of air flow into the fuel bed from holes in the floor of the combustion chamber. Since the pre-heated air flows vertically, back-drafting out of the fuel door in a Rocket type stove is easier to overcome. The jets of air super-heat the charcoal layer underneath the sticks of wood. The hot jets of air emerge from the charcoal and pierce the laminar flames emitted by the wood creating turbulent eddies that stir up the flames to enhance the speed of mixing and combustion. The turbulent combustion zone creates short, intense flames that burn the fuel more completely before they cool off too much to sustain combustion. The increased velocity of the higher temperature flue gases also improves heat transfer efficiency. When the Winiarski sunken pot Rocket stove with chimney is combined with the Jet-Flame the increase in combustion efficiency results in a truly improved stove with the ability to protect health. Since the stove and chimney do not leak in lab tests the stove does not emit fugitive emissions into the kitchen. The stove achieves all ISO 19867 Tier 5 ratings for both thermal efficiency and emissions of CO and PM2.5. In 2004, ARC was hired by the Shell Foundation to bring the Rocket stove to India. Protecting health was a component of the project. Unfortunately, the natural draft Rocket stove was not clean enough burning to accomplish the task. Higher temperatures and a lot more mixing were needed. We wish that, when asked for a health protecting stove, we had been this far along. It has taken a while to make some progress. Test results from vented (with chimney) Sunken Pot Rocket stove using Jet-Flame accessory © 2020 Aprovecho Research Center/Advanced Studies in Appropriate Technology 76132 Blue Mountain School Road, PO Box 1175, Cottage Grove, Oregon, 97424 - USA (541) 767-0287 • www.aprovecho.org

[Sam Bentson]

Dear Abraham,

the results of testing this stove using the water boiling test are shown in our book, “Clean Burning Biomass Cookstoves”. The book also talks about the bottom air technology that is used in the Jet-Flame. We got 11.8 mg/min of PM2.5 when the stove was carefully operated at 2.5 kW. It can make much more at high firepower. Since this stove has a chimney the emissions are directed out of the room.

http://aprovecho.org/?paybox_id=139

Kindly,

Sam

On Sep 18, 2020, at 12:40 PM, ALLOTEY ABRAHAM <aaaal...@yahoo.co.uk> wrote:

DEAR SAM 

PLEASE WHAT WILL THE RESULT BE LIKE WITH THE ABOVE STOVE WITHOUT THE JET-FLAME

THANKS

ABRAHAM ALLOTEY

GHANA

On Thursday, 17 September 2020, 18:58:31 GMT-7, Aprovecho Research Center <in...@aprovecho.org> wrote:

A Tier 5 Rocket Stove Sam Bentson, ARC Lab Manager, and David Evitt, ASAT COO, developed the Jet-Flame with Shengzhou Stove Manufacturer and Dr. Dan Lieberman and Dr. Mike Barbour at the Gates funded Global Health Labs  The cast iron Jet-Flame sends 30 jets of pre-heated air up into the burning charcoal and wood in an open fire, sand/clay stove, or in a Rocket stove. It is patterned after industrial burners that position jets of primary air underneath the fuel bed to clean up combustion. Both Underfeed Stokers and Fluidized Bed Boilers use primary air that enters the fuel bed from underneath the fire.

In 2013, with DOE funding, ARC built a bottom-air-only prototype stove and has been experimenting with improving the technique, resulting in the Jet-Flamecombustion chamber accessory manufactured by SSM in China. There are several advantages in a bottom-air-only approach. The jets of air flow into the fuel bed from holes in the floor of the combustion chamber. Since the pre-heated air flows vertically, back-drafting out of the fuel door in a Rocket type stove is easier to overcome. The jets of air super-heat the charcoal layer underneath the sticks of wood. The hot jets of air emerge from the charcoal and pierce the laminar flames emitted by the wood creating turbulent eddies that stir up the flames to enhance the speed of mixing and combustion. The turbulent combustion zone creates short, intense flames that burn the fuel more completely before they cool off too much to sustain combustion. The increased velocity of the higher temperature flue gases also improves heat transfer efficiency.

When the Winiarski sunken pot Rocket stove with chimney is combined with the Jet-Flame the increase in combustion efficiency results in a truly improved stove with the ability to protect health. Since the stove and chimney do not leak in lab tests the stove does not emit fugitive emissions into the kitchen. The stove achieves all ISO 19867 Tier 5 ratings for both thermal efficiency and emissions of CO and PM2.5. In 2004, ARC was hired by the Shell Foundation to bring the Rocket stove to India. Protecting health was a component of the project. Unfortunately, the natural draft Rocket stove was not clean enough burning to accomplish the task. Higher temperatures and a lot more mixing were needed. We wish that, when asked for a health protecting stove, we had been this far along. It has taken a while to make some progress.

Test results from vented (with chimney) Sunken Pot Rocket stove using Jet-Flame accessory © 2020 Aprovecho Research Center/Advanced Studies in Appropriate Technology 76132 Blue Mountain School Road, PO Box 1175, Cottage Grove, Oregon, 97424 - USA (541) 767-0287 • www.aprovecho.org

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Sam Bentson

General Manager

Aprovecho Research Center

www.aprovecho.org

Office +1-541-767-0287

WhatsApp +1-458-201-2270

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76132 Blue Mountain School Road

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