Sorry correction: my wife reminded me and its been more like minus 28c average. Wind chill excluded. Lol H
On 2014-01-05, at 9:50 AM, Henri Naths <[email protected]> wrote: > Hi Ken > Thank you for your good analysis of your wood stove. I know there is a better > design and I'm not sure if my stove is better or not. > Here is the thing. I burn spruce. My supply comes in 5 to 8 inch round logs > dried for ~3 years. Not sure mc but guess around 15%.-20 % I try to maintain > a very hot temp so the entire logs gasify and burn over a 12 hr period. > (Absolutely no fuel prep. splitting etc is mandatory lol ) It's very fickle > in setting damper and air intake but for the most part I am successful. The > refractory bricks helps a lot. So that is 2 burns over a 24 hr period. ( it's > been averaging minus 20 c over the last two months here so not much > choice)Ive run numerous test of my theory for max efficiency under which > this stove operates and settled on this operation because when the stove is > shut down anywhere at the height of its max temperature and burn cycle and > allowed to cool to 20 c it can be relight with a single match. > The volatile gases including h2o could be better used for sure. They cool and > condensate on the inside walls of the stove and flue before they frac. > completely resulting in biochar. The problem being the gases should be > reheated, frac.ed with a catalyst and burned where the heat would be a > benefit to the logs for pyrolysis. Thus enhancing the entire burn + 20%. ( > +++ considering the exponential advantage of said catalysis and resulting > heat) > A fluidized bed would also be an advantage. > I hope this helps. > Yours truly > Henri Naths > > On 2014-01-05, at 4:11 AM, Ken Boak <[email protected]> wrote: > >> Jason, >> >> Thanks for the interesting comments. I suppose that firebricks are a simple >> capacitive thermal mass, to prevent the outer casing of the traditional cast >> iron stove from seeing the worst effects of thermal cycling, and to prevent >> excessive surface temperature. >> >> Taking this capacitive idea to the max, I guess is the masonry stove, which >> is all thermal mass intended to absorb and slowly release the heat from a >> brief but intense fire. >> >> I have magnetite bricks left over from an electric storage heater (common in >> the UK). My intention was to experiment with these for heat retention. >> >> What is the problem with pyrolysis occurring too early? Is it simply >> because fuel is pyrolysing in the wrong place, and there is no means to >> transfer the pyrolysis gases to the combustion chamber, or is the problem >> tar generation in the fuel magazine? >> >> My motivation for design is a more efficient woodstove, which radiates more >> heat into the room in which it's located - say the living room, plus >> provides adequate hot water via a heat exchanger to provide heating for some >> additional rooms and hot water. >> >> The nominal 8kW stove I have at the moment fails to produce much radiant >> heat, and I am sure that the simple heat-exchanger tank at the back of the >> combustion chamber seriously effects the combustion temperatures resulting >> in more emissions and poor, inefficient combustion. For this reason I >> believe that the only way to control emissions and combustion temperatures, >> is to first gasify the wood fuel and then burn the wood gas at high >> temperature with preheated secondary air. >> >> Traditional stoves generally lose a lot of heat straight up the chimney. >> Whilst this generates draft, it is a major cause of inefficiency. Some heat >> could be recuperated for secondary air pre-heating, using a simple >> concentric heat exchanger made from twin-wall fluepipe. >> >> A good stove should be easy to light, be easy to load, easy to clean out >> ash. Additionally it should have a convenient batch burn time, and the >> ability to control the heat (turn down), without too much loss of >> efficiency. The stove should be capable of handling the predominant fuel >> type (say split logs) without additional fuel preparation. >> >> There may be good reason to have the stove non-reliant on electrical power, >> relying on natural draft and thermosyphoning for it's normal operation. >> >> These are the features that I consider necessary to meet customer >> expectations. >> >> Having intensively run my existing stove for around 14 hours per day for the >> last 16 days, as the primary source of heat over the festive holiday period, >> I am tolerating its less than ideal performance, but am now certain that >> there must be a better design. >> >> >> regards >> >> >> Ken >> _______________________________________________ >> Gasification mailing list >> >> to Send a Message to the list, use the email address >> [email protected] >> >> to UNSUBSCRIBE or Change your List Settings use the web page >> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org >> >> for more Gasifiers, News and Information see our web site: >> http://gasifiers.bioenergylists.org/ _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/
