permaculture

[Lawrence London <lfljvenaura@gmail.com>]

Attention: John d'Hondt:
==================

On 8/2/2013 2:08 PM, T A Redding wrote:
> i personally think the opposite, the guys reputation got sullied when he
> did not help his potential customer out but instead took the attitude of
> tough luck you pressed the wrong key, so it was a good lesson to me to not
> do business with him, good customer service means sometimes going an extra
> step. sometimes we are too quiet and dont object to things jmo trudie

John and Paul have been friends of mine for a long time; we all share a 
deep interest in permaculture.
I think it would be nice if Paul offered John store credit toward 
purchase of the DVD download or disk
or even refunded his money. Whenever and wherever I do business online, 
that is S.O.P., even more so nowadays
because companies are highly sensitive to reputation issues (has to do 
with word of mouth being the best advertisement)
and strive for customer satisfaction and positive transaction experience 
which means repeat sales to that customer.
There's no need for permaculture people to play economic hardball with 
one another.

I recently found and posted about a website with instructions on 
building a highly functional rocket stove. This info answers many 
questions the average stove builder will have, i.e.
aeration, where, how much, etc. This resource may be all one will need 
to design and build one that works really well, small, medium or large 
(proportions will need to be adhered to
as size increases).

The definitive article on rocket stove design and construction with 
downloadable video and drawings.

Rocket stoves use twigs to cook food quickly, efficiently

Mark Frauenfelder <http://boingboing.net/author/mark_frauenfelder_1> at 
3:02 pm Thu, Jun 26, 2008

http://boingboing.net/2008/06/26/rocket-stoves-use-tw.html

When I visited Kelly Coyne and Erik Knutzen of Homegrown Evolution 
<http://www.homegrownevolution.com/>  
http://www.homegrownevolution.com/  last week they showed me the rocket 
stove they made in their backyard. Theirs is quite fancy because it is 
made of bricks. They sometimes use their rocket stove to fry a meal in a 
skillet.

The rocket stove was invented about 10 years ago by Dr. Larry Winiarski 
at the Aprovecho Research Center in Oregon. It consists of an 
elbow-shaped combustion chamber (usually made from metal cans) 
surrounded by insulating material (often a large can filled with sand). 
It uses twigs for fuel, so it's ideal for areas where the trees have 
been depleted.

Here's a video from the Aprovecho Research Center that shows how to make 
a rocket stove 
<http://www.aprovecho.org/web-content/media/rocket/rocket.htm>. 
http://www.aprovecho.org/web-content/media/rocket/rocket.htm

   200806261447.jpg
   <http://www.boingboing.net/filesroot/200806261447.jpg> Here are the
   first 3 of 10 rocket stove principles
   
<http://www.bioenergylists.org/stovesdoc/Still/Rocket%20Stove/Principles.html>,
   http://www.bioenergylists.org/stovesdoc/Still/Rocket%20Stove/Principles.html 
   by Larry Winiarski.

   1.) Insulate, particularly the combustion chamber, with low mass,
   heatresistant materials in order to keep the fire as hot as possible
   and not toheat the higher mass of the stove body.

   2.) Within the stove body, above the combustion chamber, use an
   insulated,upright chimney of a height that is about two or three
   times the diameterbefore extracting heat to any surface (griddle,
   pots, etc.).

   3.) Heat only the fuel that is burning (and not too much). Burn the
   tips ofsticks as they enter the combustion chamber, for example. The
   object is NOTto produce more gasses or charcoal than can be cleanly
   burned at the powerlevel desired.

Illustration from In the Wake <http://www.inthewake.org/b1cooking.html>, 
http://www.inthewake.org/b1cooking.html  a cool website on various 
simple off-the-grid tools.






Larry Winiarski's Rocket Stove Principles

Dean Still, April 2002

http://www.bioenergylists.org/stovesdoc/Still/Rocket%20Stove/Principles.html

Dear Friends,

I was typing up Larry's latest simple stove principles for Aprovecho's

newsletter, "News From Aprovecho", (two to three times a year, $30/year,

describes activity, I'm editing number 59) and thought I'd send it along.

Reflecting on the Rocket I might point out a interesting point: no secondary

air. I've tried adding heated secondary air into the top end of the internal

chimney above the combustion chamber but haven't noticed an improvement in

amount of smoke or in fuel efficiency. I ended up thinking that enough

primary air is left at the top of the combustion zone anyway. Adding air may

just reduce temperatures. I'll test this further with better equipment.

The Rocket stove is trying to create supportive conditions for complete

initial combustion which seems to pretty much work when the right amount of

fuel is introduced. The added draft created by the insulated chimney above

the fire pulls in lots of air, which like a fan, makes a hotter, vigorous

burn.

Anyway, here are Larry's principles of stove design:

Best,

Dean

Rocket Stove Principles

Dr. Larry Winiarski

Technical Director

Aprovecho Research Center

Apro@efn.org

1.) Insulate, particularly the combustion chamber, with low mass, heat

resistant materials in order to keep the fire as hot as possible and not to

heat the higher mass of the stove body.

2.) Within the stove body, above the combustion chamber, use an insulated,

upright chimney of a height that is about two or three times the diameter

before extracting heat to any surface (griddle, pots, etc.).

3.) Heat only the fuel that is burning (and not too much). Burn the tips of

sticks as they enter the combustion chamber, for example. The object is NOT

to produce more gasses or charcoal than can be cleanly burned at the power

level desired.

4.) Maintain a good air velocity through the fuel. The primary Rocket stove

principle and feature is using a hot, insulated, vertical chimney within the

stove body that increases draft.

5.) Do not allow too much or too little air to enter the combustion chamber.

We strive to have stoichiometric (chemically ideal) combustion: in practice

there should be the minimum excess of air supporting clean burning.

6.) The cross sectional area (perpendicular to the flow) of the combustion

chamber should be sized within the range of power level of the stove.

Experience has shown that roughly twenty-five square inches will suffice for

home use (four inches in diameter or five inches square). Commercial size is

larger and depends on usage.

7.) Elevate the fuel and distribute airflow around the fuel surfaces. When

burning sticks of wood, it is best to have several sticks close together,

not touching, leaving air spaces between them. Particle fuels should be

arranged on a grate.

8.) Arrange the fuel so that air largely flows through the glowing coals.

Too much air passing above the coals cools the flames and condenses oil

vapors.

9.) Throughout the stove, any place where hot gases flow, insulate from the

higher mass of the stove body, only exposing pots, etc. to direct heat.

10.) Transfer the heat efficiently by making the gaps as narrow as possible

between the insulation covering the stove body and surfaces to be heated but

do this without choking the fire. Estimate the size of the gap by keeping

the cross sectional area of the flow of hot flue gases constant. EXCEPTION:

When using a external chimney or fan the gaps can be substantially reduced

as long as adequate space has been left at the top of the internal short

chimney for the gasses to turn smoothly and distribute evenly. This is

tapering of the manifold. In a common domestic griddle stove with external

chimney, the gap under the griddle can be reduced to about one half inch for

optimum heat transfer.