[Stoves] The upside of Down feed

[Crispin Pemberton-Pigott]

Dear Friends

 

Agua Das is using an air aspirator for draft – a concept I strongly endorse for use inside a home because it puts the whole system under negative pressure, basically eliminating the possibility of CO leaking into the room.

 

I think a significant difference is that Agua has a controlled secondary air supply and Alex’s simple version looks like it draws all air through the grate, or through the fuel at the grate. With a predictable fuel there is no problem doing this once the geometry is set (for that fuel).

 

Regards

Crispin

++++++++

 

Alex and list:

   This is to further explore the idea of char production in your device (which we should call??).  

   In the exchange below, I think I have to side with Crispin - is not the fuel essentially all combusted?   Of course it is the usual two-step combustion - with pyrolysis first leaving a pile of char - which is then itself more slowly combusted?   As the char disappears, more pellets are able to fall down.  You seem to have established stable rates of pellet and air flows such that the pyrolysis zone is unable to travel up into the hopper.  

   The Venturi effect you mentioned is one drawing both pellets and air down from the hopper - yes?   (When I wrote yesterday I was fixated on char movement.)

   My reason for still pursuing the char production possibility is that your geometry seems very similar to the Dasifier (concept of Agua Das - being ccd).  Das tells me he can produce char.  Somehow your grate has to be replaced by one that allows char to fall through??   Is there any alternative then to an auger?

   Might it make sense to replace the tall chimney in some circumstances with a blower?  (To lower first costs - allowing a much shorter chimney?)

   Is this development related at all to backup heating of your greenhouse?  Or manly intended for home heating?  Any applicability to cooking?

Ron

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