[Stoves] Lowering emissions

[frank]

Crispin, and others,

If you take Popsicle sticks and drop them into a top loader or push them 
into a rocket 100 times and get a range of packing densities that range 
will be different than if you did it for the same type of wood but 
shaped like straight round sticks or again with twisted  twigs even if 
all weigh the same and the same size.  I am suggesting we actually take 
the fuel and load a fire box over and over to get the typical void 
space.  Some fuels will pack with a wide range of void spaces and other, 
more straight or made of 'ball' shaped pack with very limited range. 
 From this we could set up a classification system on a scale of size, 
shape, packing void space and move on to many more classes like carbon 
densities moisture etc.

Once the Fire Box is filled with a know class of fuel we could inject in 
cold or preheated air, or blow in air at different points in the box, 
insulate the box or not, - do what is needed to find the best way to 
burn the fuel. Then make the stove. The constant that can't be changed 
is the fuel because that is whats available and the natural packing of 
that fuel based on shape etc. We need to know the conditions to burn 
that fuel when it is packed the way it drops into a box or pushed into a 
box.  We need to know the boundaries of the fuel at hand to make the 
burning conditions cover all reasonable typical limits of that fuel.

There are lots of variables, as you mention. But these are quantitative 
variables with ranges. And the variables between logs, split fire wood, 
grasses pressed into balls and twisted twigs are different enough from 
each other to be in its own classification.

Just a suggestion.

Frank



Crispin Pemberton-Pigott wrote:

>Dear Frank
>
>I agree that your proposal would find the bulk density.
>
>What is really difficult to determine us the best conditions for burning a 
>fuel.  There certainly is no 'box' that will give you an answer because some 
>boxes are preheating  air, running complex heat flows, bringing in secondary 
>air, insulating portions and not other and so on.
>
>The point is that when the 'best' is arguable, there is no way to deal with 
>fuel packing.  Packing is part of the combustion process / operation of the 
>stove.  Another person could operate the same stove with a different fuel 
>packing strategy and get better emissions.
>
>I think a Rocket Stove could arguably be described as not have a fuel 
>packing rate at all because it can be varied at will.  In top loaders / 
>batch loaders the packing is very important and the quantity of fuel is 
>related to the moisture and surface area/volume ratio.  Different woods need 
>different strategies, also age and length.
>
>It is about as complicated as anything you can think of!
>
>Regards
>Crispin
>
>----- Original Message ----- 
>From: "frank" <frank at compostlab.com>
>I think a classification of fuels and fuel packing is really needed.  It
>would be an easy  thing to do if one was to take a container shaped like
>the fire box being used, fill with fuel much the same as when filling
>the stove fire box then pour in sand to get the particle density, bulk
>density and void space. Numbers you need are:
>Volume of fire box (ruler)
>Wt sand that fills the fire box (scale)
>wt wet fuel in filled fire box (scale)
>wt of sand that flows in around fuel (scale)
>...
>
>
>
>
>  
>

-- 
Frank Shields
Soil Control Lab
42 Hangar way
Watsonville, CA  95076
(831) 724-5422 tel
(831) 724-3188 fax
frank at compostlab.com
www.compostlab.com