[Stoves] [MHAtech] Re: Top lit updraft combustors

[Ronal W. Larson]

> Norbert  et al


> On Dec 18, 2017, at 3:57 PM, Norbert Senf <norbert.senf at gmail.com> wrote:
> 
> On Mon, Dec 18, 2017 at 5:42 PM, Ronal W. Larson <rongretlarson at comcast.net <mailto:rongretlarson at comcast.net>> wrote:
> Norbert et al,  adding the stoves list.
> 
> 	See inserts.(snip)
>> 
>> I modified our own heater as an experiment, changing it over to the new Austrian eco-labelled air specification, and using airtight hardware to eliminate or reduce the use of the flue damper. Also as an experiment, I have been shutting the air early and harvesting the coals the next morning, putting them into an airtight ashbucket until they are cool. Burning roughly 7,000 lb of 20% moisture hardwood last winter, in 60 lb batches, I made roughly 500lbs or so of biochar. I have not heard of anyone else doing this yet.
> 	[RWL3:  Not clear yet - is your approach safer?
> 
> Yes. If I have an airtight stove, I can control the flow with the combustion air inlet and effectively stop the flow in the chimney. If the stove is not airtight, chimney draft will suck in "false air" through the leaks and bleed heat, thus lowering efficiency. The whole system is depressurized by the chimney, so no possibility of leakage into the room.
	[RWL:  I sometimes hear of reverse flow in chimneys.  Not  to worry in your systems?

>  
> 		If optimized for char-making (and safety), instead of 500/7000  (roughly 10% in energy terms), might you have gotten up (energy terms) to 15 or 20%?
> 
> Good question. Makes sense that you could increase the yield through R&D. Would 20% be considered a high number for yield?
	[RWL:  No - medium .  I almost never varied a percentage point from 25% by weight (multiply by about 30/18 to get energy).  But we hear 30% by weight sometimes (low temperature char).

Ron

> 
> -- 
> Norbert Senf
> Masonry Stove Builders
> 25 Brouse Road, RR 5
> Shawville Québec J0X 2Y0
> 819.647.5092
> www.heatkit.com <http://www.heatkit.com/>
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