[Stoves] Adding a fan

[Dean Still]

No, that's right but the batch fed fan stoves do better.

-----Original Message-----
From: Roger Samson [mailto:rsamson at reap-canada.com] 
Sent: Saturday, May 20, 2006 1:29 PM
To: 'Dean Still'
Subject: RE: [Stoves] Adding a fan


Hey Dean looks great. congrats 
Is the pm 162.4 vs 9.7 or is that an error?
Roger
-----Original Message-----
From: stoves-bounces at listserv.repp.org
[mailto:stoves-bounces at listserv.repp.org] On Behalf Of Dean Still
Sent: Saturday, May 20, 2006 12:39 PM
To: 'STOVES'; 'Paul van der Sluis'
Subject: [Stoves] Adding a fan

Dear STOVES,

I have had some luck adding a fan to a Rocket stove. Preliminary results,
photos and a chart are posted on the REPP site. 

The combustion chamber is made from insulative firebrick inside a 20 liter
bucket. The fan blows air into a sealed annulus between the outside of the
firebrick and the inside of the metal container. Drilled holes through the
brick blow jets of air into and above the fire. The holes are all pointed up
a bit so that the direction of flow is up the L shaped Rocket combustion
chamber. The long sticks enter the stove from the side as usual.

Batch fed fan stoves like the ones built by Dr. Tom Reed and Dr. Paul van
der Sluis are remarkably clean burning. I wondered if it would be possible
to do the same thing in a side-feed stove. Stoves without fans often do not
have good mixing of wood gases, air, and flame so uncombusted gases escape. 

The World Food Program Rocket stove is made from used metal food containers.
It is low mass and pretty much represents the cleanest burning Rocket type
stove. Time to Boil 5 liters is 22.7 minutes. Fuel used to boil one liter
and simmer it for 45 minutes is 68.1 grams. CO produced during this task is
0.8 grams. PM produced is 162.4 micrograms. Firepower is 5532 watts.

Adding a fan that blows air into and above the fire improves performance in
this type of stove. Time to Boil in the firebrick fan Rocket is 14.0
minutes. Fuel use is 56.9. CO is 0.3. PM is 9.7. Firepower is 5954.

The air is not preheated except that it goes through 3 inches of insulative
.6g/cc firebrick in the drilled 1/8th inch holes. The fan is 10 watts on
full speed. A 3 watt fan did not seem to do as well.

I'll keep on changing things to try to lower PM.

Adding an inexpensive fan even to a sidefeed stove is an effective way to
increase performance.

Dr. Tami Bond said to us yesterday that the permanent brown cloud over
India, China, etc. is caused in large part by the burning of biomass. I was
just in India for 6 weeks and away from the cities in the countryside the
sky is no longer blue. The work that we are doing here on STOVES etc. is to
change back the color of the sky to its intended color! 

Best,

Dean

PS

By the way Stove Camp is August 18-22 here in Oregon. Hope that you can
come!

Shall we concentrate on $5 fan stoves? 

 


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