Hello Lewis,
I’m just glad all the past experimenting was trucks and gasifiers vs airplanes because there have been a lot of crashes.
Hello Lewis,
I’m just glad all the past experimenting was trucks and gasifiers vs airplanes because there have been a lot of crashes.
LOL you wouldnt belive the aircraft crashes I have walked away from.For some reason people just dont think you can walk away from a plane crash or particularly a helicopter crash but they are pretty survivable. In most cases you simply land fix the problem get it running and hope nobody noticed!
Steve, i did find an Thai style gasifier, used, tested and performed well
i will look up where the study was, but have the picture here already
Hello KoenVL
Remember that this topic is about straight forward logic evaluating woodgasification effeiencies cycles.
This can be done without compex, confusing and I will say, all too often deceitful applied scientific mathmatics.
Very easy. Every time you demand or make a physical structure change; a change from one form of energy to another there will be an energy used cost loss in the intial potential energy pool.
And every time you do/demand one of these changes there will be a waste byproduct created that then has to be dealt with. Cooking: the pot and pans get residue encrusted and then need cleaning. This wastes some of the original material stock and now takes pumping, heating, scrubbbing energy. Then dirty water needing cleaning! Metals become heat and pressure cycled worked crystalized, brittle, crack and oxidize and need melting down and reformed. Lots of energy has to be made, put in and then expended to do this. Systems become unfavorably energized: inertia, heat, magnetics, radioactive. Need to be de-energized and brought back to a nuetral starting stable condition.
These are all realities in the real world of DOing things.
(MikeL now skip to the last two paragraphs)
Your AIT charcoal system looks interesting as using more indegious materials and nice being an in the ground based. Ha! “Down to Earth” we would say here (means practical, real people usable).
Puzzling to me though why they used such a comlex reactor system for pre-refined and densified charcoal. That part of if looks to be readilibly raw wood chunked fueled.
What I next say please do not take as a criticism of charcoal gasifing.
Charcoal gasifing IS the best for small engines use and areas with much growing biomass and preople wanting and willing to learn to make and use it responsibly.
Here to soften what I will next I include purpose grown and ground up and pressure densified raw biomass fuels and ethanol.
Full cycle efficiency with raw wood chunk fed gasifier you can beat hands down efficiency wise any other IC engine fuel making process.
Yes. A-N-Y process.
I start easy. Ethanol motor fuel. We now in the United States are Federal topdown government mandated to only use 10% ethanol blended fuels. We are the largest producer of corn/maize in the world. Since this new law now 49% of ALL corn production is diverted to motor fuel enthanol producing. Corn is an annual crop that requires annual ground plowing down to bare soil to replant. Petroleum Diesel fuels these tractors. Not food intended much high tech no-till full spectrum killing petroleum based herbicides ground prepping now done here. Petroleum diesel fuels the tractors to weed till, harvest, and transport to the ethanol making plants. The soils are depleted and must be quickly, annually revitilized using manmade fertilizers made from natural gas; trasported and applied again with diesel powered equipment. Many times the growing fields must be pumped water irrigated - diesel or natural gas fueled pumps and generators. For market optimizing and to insure a year around ethanol feed stock of this only seasonally capability grown corn then much corn must be dryed and stored - takes much natural gas/methane to do this. This is also the cooking heat fuel within the ethanol plants. Very, very well doculmated that we DO not produce any net energy. Ethanol production must be energy subsidized. I must pay a 20% additional cost now for non-enthanal “off-road” gasoline for critical engines like my German chainsaws.
Trees selected for the climate and the soil once past early year of nurturing will tend well to themselves.
Ahh. But to maximize “investor” yield per acre these are now planted not in self shading and nurturing forests but in energy plantations. Diesel equipment to competitive weed/till in between the rows now. Diesel powered equipment to do the limbing and thinning. Petroleum used to make the mono-culture saving herbicides ands insecticides. Diesel powered equipment to transport and apply these. Then diesel powered equipment to do the harvesting, and chipping, and transporting. Natural gas now used to do the chipped fuel stock dring. Diesel or natural gas for the electricity used to now operated the grinders and the fuel pellet or briquette making machines. Now again natural gas or petroleum to make the waterproof storage sacks. More diesel to transport and distribute this “Green” fuel. Pour the sacks of “green” pellet fuel in and push the start button. Easy.
I have walked through and visited these operations.
If the fuel stock is sawmill, wood procenning mill by-products then the economy efficiency of densified wood fuels works.
From standing trees to densified fuel pellets NOT a net energy production fuel.
From standing trees to chipped fuels YES it can be . . . . but only if these chips can be used “wet”, “green” and not have to be outside energy dried and outside energy with bulk loss sorted.
Charcoal. First you must drive off as much as possible the always excessive “green” moisture content. The sun is “free” but unreliable too much of the year in most of the world. So 15-25% of the biomass fuel energy must be sacrificed to do this drying reliably year round. This very wet warm visible water vapor humidity driven off initially out of charcoal makers that has almost no secondary use.
Then you must drive out the volitals from the carbon/mineral(ash) cell cores. This can be either as a total % of the fuel used up; Including The Char burnt to produce the heat to do this. Or in a heating fuel process that burns the driven out volatiles to make the heat with even some high value liquids produced system. Tricky, tricky to do this. It will depend much on the volatiles to carbon ratio of the fuel stocks - have to have enough energy in the volatiles to do this and NOT have to go into a char consumning heating cycle also.
WHY so important to pre-dry the fuel to save for the charcoal freeing heat part of the cycle.
Once you make the nice char then you have to cool it (losing heat energy) to be able to store it. A raw wood gasifier takes internally procued charcoal as hot. Ha! Then when you do use the stored charcoal it you must heated back up to reactive temperatures useing up some of the char energy to do this heating. These energy used up steps in charcoal making and heating up using then cannot be made into motor fuel gasses.
So on these and all other motor “fuels” including electricity COUNT THE CONVERION STEPS.
Count up the hidden, forgotton energy imputs needed. In a petroleum refinery 30-40% of the petroleum potential energy raw fuel delivered get used up in the refining.
Plant trees. Harvest trees. Two step chunk up trees into gasifer fuel or direct heating fuels. Direct gasify in a GOOD energy/heat recouping and recycing raw wood fueld gasifier AND IC engine system.
You will win the effiency test every time. You can do this with the least of outside resources useage. The least wastes produced. And the easiest reuse and disposal of those wastes.
The key to this is do it directly for yourself with the simplest possble systems.
Add idealistic complexity anywhere and you lose true effeiency.
Woodgasification the ANSWER for everyone? Of course not.
We are at ~one on a million now. Really, bet 7000 are doing this now in the world. I am certain the World could support this at a one in 100,000 level sustainably with those directly useing and still able to be local, free and independent.
It is when you try and make woodgasification the “for all” systems that it takes a Religious fervor with Priests, Fascist furvor with Leaders, for the TopDown directed madates like “all gasoline motor fuel made and distributed in the United States WILL be a minimum 10% enthanol blended” to make it work.
“Good Ideals always leads to bad Idealism”. And it is this idealistic “I know better for you” that is the real individual freedom thief. Starve the talking heads with the view of your backside walking away. Only you, can free you. Tune in. Opt out.
Wood fuels ARE the Freedom fuels.
As always, my own opinions that I do actually live by.
Regards
Steve Unruh
Steve,
my picture came in reaction of your statement
“Bluntly the Australian, Indoneasian and Thailand designers would be more wrong than right on how to make a gasifier system work year around up here in the great, cold, six months of the year frozen lands. They always design around water cooling, washing and filtratrion. NOT good for frozen areas. And frozen climate Designers up here no matter how talented are just as failure prone on how to make a gasifier system function year round down in the equatorial area’s of the world. Thier systems always undercool in equitorial ares and are too out of user regions matrials depemdent. Many, many documented reports of failures tring to do this now in the last 30 years. Read the onsite available here FOA 72 publication. A study in across world regions tech transfer failures.”
I can follow and do follow your arguments on conversions and so on, but i can think behind my own borders. Every link in the whole chain of economics has to be
considerate. And doing the best you can with the means and knowledge available leads to efficiency. the most efficient system does not mean the best system.
Think behind the borders, you only can do what is possible not what is best.
Hi Steve
At what temperature does wood gasify ? Assuming the moisture at 20%
thanks
Patrick
Hello PatrickJ.
You may think you are asking a simple question the way you phrase this. But you are not. Takes a minimum of four different overlappping range of temperature zones to turn a piece of wood into “gasified” motor fuels. Jim Mason discribes this well in words up in Gasiification Basics. Marco Cioni recently put up an excellant picture on these four tempersture zone ranges.
Let me reverse this on you Mr Mechanical engineer/jimcracky millwright man: how many coils does it take to make a good spring??
See!? Are you daft man, wouldn’t you say?
Whats your metal type? Round or flat stock? How much working starting length to ending length are we talking about?
In fact do you want it to be a compression spring or a tension spring?
Ha! See it all must start with the question and answer of “Why are you asking? And for what purpose?”
I “think” you want to know the temperature to expect at your gas outlet crossover tube on your new WK between the reactor hearth and the heat exchanger? OK then.
The glowing char reduction zone gasification works best at a minimum range of 800-850C. Below 600-650C this FINAL STAGE gasification conversion effectivly stops. The super highly insulated all SS systems I have worked with aimed for CHP and GTL the out going gas is held at 800C. Actually heat colors the SS gas tubing. Most guys using WK’s are quoting 500-600F (300-350C) at this point? Since the aims are differnt to fuel larger IC engines with as wide of possible turndown ratio gasifier made of affordable carbon steel then very smart to be bleeding off heat anywhere as widely distributed out as possible after the gas reduction phase has been completed like the lower hearth reactor jacket and ash collection areas and all outgoning transfer tubing. Lots of the Euro fellows even intentionally forced cool here. Helps stablilzed the CO gas componet. Drops out ash cored soots sooner into the hearth lower section. And “They” would think you are nuts insulating down there!
Different horses for different courses.
The WK System wants to force as much finished gas heat as possible with good metals life sensibilty into the heat exchanger for the best overall system fuel ecomony. Where you do your inital gas cooling you will get lots of soot dropping out. Gas velosity has much to do with this also. Why the heat excahnger is designed to handle this drop out and be easily cleaned. Expereinced learned.
From my over the shoulder looking and listening the complete WK System actually works with six different active temperature zone ranges for the complete wood fuel in to gasses out conversion.
Regards
Steve Unruh
Great points Steve and Patrick. If I normally see 1350-1450 F (732-787 C) on my TC located 1" above the grate dead center (approx 4-5" below hottest char) then I am “in the ball park” ??
Thanks for the info.
Let me rephrase my question.
At what temperature would a piece of say pine 20% moisture spontaneously combust ?
Thanks patrick
I will try fine “Jim Mason discribes this well in words up in Gasiification Basics”
Looks like 600-900 F.
Pine, Oak and other materials autoignition temps: http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html
Jim Mason’s piece: http://driveonwood.com/learn/basics-woodgas
According to Jim it’s around the 240 c mark.
“Biomass begins to “fast decompose” with once its temperature rises above around 240C. The biomass breaks down into a combination of solids, liquids and gasses”
Chris that is a very useful website so between 300 - 480 c, 570 -900f for soft to hard wood , pity they don’t list wood gas.
Thanks patrick
Thanks guys for the good information and direct links put up.
Patrick a piece of pine wood at 20% moisture cannot spontaneously combust. It is impposible. You cannot even make it burn thrown into a hot glowing charcoal bed UNTILL at least the surface layer has that 20% moisture heated up an driven off.
In a nice airtight woodstove then with an established glowing hot char bed to provide the heat then it will selfcontained gasifiy convert quite nicely as the internal vaporized moisture and wood volitals are driven out through the now wood peice carbon outer charred layer. “Hot sear seal those steaks and roasts first to keep the juices in!” This possiblity will heat quench die on my experience above about 25-30% fuel wood moisture content. And in a wood stove the process will crash as soon as you’ve used up the pre-established glowing hot charbed Heat that is actually driving it along. The buring woodgases out od the fuel piece is not enough to sustain. Solution in a wood stove is to then over air switch back to a straight oxidization char burn with the piece remaining char core to remake the hot char bed heat reservior before the next raw wood refuel. You Must have good air control and a thermal brick lining to do this. Easy to run the char heat down too low. Even easier to over fuel with raw “wet” wood robbing to much heat initially. Smoky then because it is NOT combusting water vapor heat quenched let alone gasifing reducing fuel gasses converting.
I answered this way because you also wood stove operate and can now See the correspondences of you set-up and now watch for them with just a little viewing window.
Mr Waynes newer hopper system developements are to vaporize, then condense out and Removed Out Of System the excessive unbeneficial fuel moistures Before they would cause hearth core heat quenching problems. But not TOO much removal or you kill the better H2 and CH4 fuel gasses production. FUEL WOOD CAN BE TOO DRY Also for best gasification results! Processes too fast, too hot and makes too much soot.
His advanced hopper system IS effectively the First of Six very controlled temperature zones in his WK System that will not show in Jim Masons explaination and Marco Cioni’s process picture. The last as the hearth core internal and external heat exchanger systems. Also not in the standard gasification canned explanations.
Now are you actually asking me why your system with the top opened up after a delay whent Whoosh! hair singeing?
Whole different story to that. Wasn’t the actual wood that did that. Pyrolisis vaporized tars and oils are very powerful along with drawn up soot/char particle fuels. First the lower woodgas went up when the air oxegen finally was drawn down to the glowing char area - that pressure whoosh up and out then sucked up a lot of soot char particles ignighting and this last heated up and ignited the pyrolisis tar/oil gases. You had your very own little chain reacted pocket thermalnuclear event right down to the mushroom cloud. This was all talked about on Carl Zinns expereince thread. Break the chain to prevent the severity of the event.
Regards
Steve Unruh
Hi Steve
I was looking for the ideal temperature for your incoming air to hit the wood and start the gasification / vaporizing of the wood process.
I see your point as to having to drive off the moisture first. Then the spontaneous combustion of the wood.
Thanks
Patrick
@ Matt
To calculate the efficiency is generally not so difficult. How much potential energy did you put in the tank , and how much “work” did you get done with it.
Basic and simple if; you only consider the input in the tank and electric produced. Use SSS numbers only Simple, Sound, Solid
International published values are : 1 Kwh produced electric power will consume +/- 1,3 Kg Wood fuel, 0,7 Kg charcoal, and so on ( published but can’t verify those numbers )
1 Kwh Produced electric power can be produced with 0,26 Liter diesel fuel ( says manufacturer )
It hits me many times when commercial manufacturers use these numbers to promote their efficiency of their gasifiers and or generators.
efficiency comes from what goes in the thank, and what nett energy is delivered
I will ad an US document about the heating values and use that one as reference.
Always use the HHV in the calculations
Diesel: - 138380 Btu/gallon , 1 gallon = 3,7854 Liter, 0,26 Liter = 0,0687 Gallon gives 9506 Btu to produce 1Kwh electric power
farmed threes: - 8852 Btu/Lb, 1 Lb = 0,4536 Kg, 1,3 Kg = 2,1385 Lb gives 18930 Btu to produce 1 Kwh electric power
Petroleum coke: 12680 Btu/Lb , 0,7 Kg = 1,5432 Lb gives 19583 Btu to produce 1 Kwh electric power
Diesel consumption comes from manufacturers data, looks to low for me… ( not sound )
farmed threes: - i think our gasifiers do better then that ( give me solid numbers )
conversion 138380 Btu = 40.5553 Kwh ( 10000 Btu = 29.3072 Kwh) ( 1 Kwh = 3412,1282 Btu)
This calculation was made based on the data received as indicated.
Don’t be surprised by the numbers, just make sure they are verifiable ( depending the source ) and use them only as reference.
I work day and night with numbers and assumed calculations, my job is to find common sense to explain them :-))
Spoken of night, here in Thailand is 03.15 am now and i am still busy
Ok , i believe in numbers, they prove themselves they are wrong…
http://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html
This toolbox has also a lot of numbers
Notice the differences
Hello KoenVL
If you use a tree wood heating value of effective usable 5000 BTU per pound or metric equivalents then the math will make much more sence. This accounts for an very real world typical average 20% fuel moisture.
All of these “calculators” always like to only quote fully heated up stabilized process numbers. Energy used heating up to stabilized conditions; and heat energy lost in post shut down cooling off are excluded. Big differences in actual daily operating realities system to system. My wife gets NEGATIVE subtacted miles per gallon with her long 10-15 minute warming ups in her car.
The real incalulated significant intangeble for DYI’s here on the DOW is fuel dependency Independence.
Priceless to be able to finger salute the whole Investor, Speculators, Commodities Traders, Social Dictocrats and life quality enslaving manipulators.
If I used a strickly mathmatical measurement I would heat my two houses with either my Govenment’s Big Hydro/Nuclear electricity or private market supplied propane like 2/3rds here do. With the high social taxes and year to year availability, maybe you will have it, maybe you will not, dependencies these always carry.
Same with chicken eggs here - $2.00 a dozen from a 3 million chicken horror house egg production factory located out in the middle of the nearest desert to support the wastes created - this IS NOT an exaggeration. Or local, neighbor small farmer grown and “illeagaly” roadside sold without the state manditory government registration, inpections, licensing, taxes or fees so then availble at only $3.00 a dozen. $6.00 a dozen for the local legal registered “organic” branded eggs. The big organic produceres lobbied our state so the state now owns the actual Organic name and this can only be used with registration and licencing. Sigh. I cannot support the resonable locals farmers as I am now on different scofflaw watch lists for my out spokness. Raise and grow my own chickens for the eggs and meat. They cannot stop or tax me for personal consumption or gift to family and friends. Depending on the hawk and coyote (giant American foxes) predator losses to my birds, my gardens fodder suppled, bug population, etc, etc, maybe $4.00 a dozen in true costs. MUCH better eggs!! Rich, rich orange yolks. People rave about our eggs.
The Freedom enjoyed is priceless!! Incalulatable.
As soon as you allow Them to put a fuel cost comparisions on woodgas from tree you already own then They now own you and you have already lost no matter how favorable the numbers would ever come out.
The security of the current fuel producers, distributors, thier investors and especially the multi-levels of governments addicted to the tax moneys is to always to first fissil fuel under price Alternative Fuels. Then regulate them unnuseable. Then step in, cherry-pick and buy them up as “failed” cheaply and suddenly they will be declared “Good” now that the profit and social control pipelines are filled up again to their benfit.
THIS WAS THE STORY IN THE 90’S WITH ALTERNATIVES after the created oil glut gutted all Alternatives worldwide.
Do read and study the FOA 72 report in the pdf’s here about 90’s bio-mass energy projects. That is the real story told.
ONLY TWO woodgas power operations survived through this gutting out! The ones with Principals who refused to use fuel costs matix comparions and DETERMINDED they were Only going to use thier own local owned wood fuels.
Ha! My topic so I can go a little extreme. Admin Chris can edit.
MY cost/value matrix factor is what I currently do have is always 3X better than anything I would have to purchase to acquire. So new to aquire MUST be 4X better. This IS sensable. Think about it. The Time to go find the new. The Time spent comparing the alternatives. Then Sales fees. Shipping fees. Taxes. VAT. Disposal costs of what you already DO have. SWMBO’s can be fierce about this.
I firmly believe only hope for woodpower IS us willing to bootleg Users. 10 years. 20 years. Watch and see. All of you.
Here. Now. Where I live in Washington and Oregon States the UrbanEcoGreens are continually lobbying to illegalize ALL woodburing for energy. No Joke. I live this. Two differert bio-mass plants proposed on old woodmill sites shouted down - so the dead trees rot and go up in annual wildfire flames.
My woodheating stoves are real $5,000. Plus systems each now to be legal and insurable here for what in the neighboring states of Idaho and Montana would have been $1500. max as all new parts.
Woodgas is the true personal individual Freedom fuel and should be respected as such. And that is what makes it far superior to Any fossil fuel.
Steve Unruh the scofflaw
Steve,
You made my point, i agree with you.
Since we feel the real power of wood, i disagree with those who just put the numbers on some paper and then use them as reference to compare.
If those numbers would be correct then there would be no difference between all of them.
i did find more then a dozen different “scientific” papers, all giving different numbers. Could it be that they don’t want the wood-gas progress and therefore just proclaim negative value’s ?
I take as reference the test Wayne performed, he did far better then any number from those “scientist”
Luckily i live in Thailand here, where they embrace the knowledge and are willing to proceed in a fast pace towards fuel import substitution.
I take it as my crusade to proof the opposition against wood gas are wrong
Grtz
Koen
Steve, Your disertation on 8/10 was one of your finest. Bravo. And then 'round and 'round we go with more figuring and pencil sharpening.
Anyone missed it should go back and read it and think about it.
I’ve included a picture showing my daily two-or-three step conversion of waste logs picked up for free all over the place and processed right here by me at Don Quixote Plaza. Happiness is a sharp chain and a Fireside Friend and a woodgasser with a good monerator-hopper.
John
Hi All
My/our normal 8-9 month rainy season has jumped started itself a bit early back in the last week of August. Many downpouring thunderstorms. I got caught with all of this upcoming rainy seasons worth of fuel wood still out drying down having a late, late start from the hanging on through the 30th of June clouds and rain. I cannot expect to be able to do any net effective outside solar wood drying again until July of next year. At lease 10 other DOW members in this same Evergreen wet western Washington State boat. Plus western Oregon, BC Canada and south Alaska members here. This is our reality.
Disaster? No. I will still burn this wood for heat over the next 9 months coached started with carry over remaining woodshed dry wood. Now though the wood heat has to dry the wood fuel. Only half the into room heat output.
Means I will have to use 2X the wood. That will mean 2X the wood handling labor and expense.
How does this related to woodgasifing for IC engine power??
Well for every 100,000 BTU’s of fuel energy you put into a piston IC engine you will get out ~65,000 BTU’s of heat. Gasoline, diesel, propane, methane you have no real fuel processing needs for these engine heats. So they are typically blown wasted away to save the engine from overheating damage. This is the CHP guys heat source.
Raw wood fuel gasifing, charcoal fuel gasifing; even vegetable oils fuel, waste motor oil fuel or motor fuel alcohol these engine heats are a very valuable needed fuel making/refining heat energy resources.
These are not a “waste” then; so do not waste them. Do not Dino/Hydro/Nuke fuel for your process heats if there is a working IC engine running near by. Put that engine to heat work!
Engine heats are the make or break heat resource that allows the use of wet/green fuel wood year around for gasification.
I will say this again: Put a working running IC piston engine in your developements right from the beginning for this needed process heats even if you will have to initially fuel it on bought out Dino fuels.
Put it’s output heats and actual fuel input demands into the system developement right up front from the beginning will save you years of developement wheel spinning going the “perfected” step by painstaking step route.
Hey “Cicerone” JohnS.
Mail box vandals got our old wooden mail box house flatten to the ground. For the new 4"x6" post I needed to pencil sharpen one end to drive it into an existing hole. Axes were all 1/4 mile away. My handy dandy FireSide Friend did the job slick.
Thanks again for the tool tip.
Regards
Steve Unruh
Hey David Laundry thanks for the compliment of reading this.
This simplfied maths efficiency approach applies well to wood stoveing for heat also.
Books and sites all will give you from 7200 to 8600 BTU’s per pound of fuel wood as optimal possible. Metric folk a BTU is close enough to calories to just use kilocals instead. What is important for discussion is the percentages. For actual functional useable space heating the gross Heat in whatever measurment is what is important.
So DavidL I just simplify this and wood stove or gasifier use an effective 5000 BTU per pound of fuel wood used. This accounts for up to 20% wood moisture and allows for a reasonable to achieve 80% heat into the house space heating efficnency actually delivered.
Then just a matter of knowing your home BTU’ per hour needs for your average heating conditions and sizing the firebox for then the amount of fuel wood by weight and volumn you will need to use in an hour to generate the gross BTU’s release that you will need.
This IS where it starts.
The rocket stove folk and nano-efficiency chasers aways system undersize here. Have something then without the flexibilty to handle exterme weather swings. Then get stuck having to fine split down and short saw chunk up ALL of thier fuel wood into fine sticks and chunks. POOR sweat efficiency in that unless you have teenage slave labor willing to work for just for peanut butter and a bed.
Ha! I’ve seen your wood stove picture.
What these “ultimate” efficiency chasers do not realize is you and I can take our oversized iron mass stoves and to heat them up to operating temperatures easily cycled as high velocity Rockets intitally. Then switch to a closed up tight air controlled hot stove mass driving a slow, slow velosity, very low flue/chimney heat loss “American” buring cycle.
We even can paper/cardboard/twizzle sticks/bark chunks over-aired “Russian” “Finn” “Swiss” rapid mass cycle heat up and thermal cycle then coast along for hours. 3-4 times refireing in 24 hours with these high mass iron stoves on very little fuel used.
And we CAN even in these, TLUD (top lite, updraft) cycle as we wish. I do this as is beneficial with the three different levels of controllable air points into mine.
Of couse the devil in the stove internal details is to get this 80% efficiency and this broad range of capabilities. Ha! My latest I can even top load dump in paper bags full of woodshed floor slivers, chunks and bark chips that’d choke any gasifier.
Takes a good, experienced, knowlwdable operator to do these streachings out buring modes.
We’er back into the Pineapple Express weather again. 50F and drizzling rain with 35 mph wind gusting the drizzle sideways. Winter in western Washington state.
Russian/Finn/Swiss mass cycle heating for this to keep from driving the house up to 80F inside.
Regards
Steve Unruh