Wood stove optimization

I find high mass in the stove isn’t that important. The mass of the house and contents becomes the thermal mass, and it is rather high.

I believe @SteveUnruh hit it on the head earlier, air flow and residence time of the heated gases equals efficiency. It’s pretty hard to beat the combustion efficiency of a modern airtight wood stove. Then the question is the flue temperature. You have to maintain a certain minimum flue temperature to maintain good draft and smoke not entering your house, and avoid excessive condensation or creosote accumulation which will burn your house down unless cleaned.

A high thermal mass stove militates against clean efficient burning, taking a long time to get up to good operating temps.

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well, I use 5 face cords of wood per year. I heat 1300 sq ft to 72 degrees in central ontario. If you were to try this with a high mass unit you would end up with a warm core and cold rooms the further out you went. Without secondary burn you would use twice the wood. You can Iive that way but I think Ill keep my airtight. You heat the air around the stove it naturally moves itself around the house heating up 2 tonne of drywall, a tonne of ceramic tiles and cement board underlay, and at least 5 tonnes of basement slab via radiant tubing. Stove was about 1200 plus the insulated chimney so under $2500 canadian. If you purchase hardwood here it costs you $100 per face cord if you have the land it costs you 2hrs of labour at least. If you change the firebrick in the stove the wear on the steel is negligible so you are good for 20 years or more. The secondary burn assembly in mine is stainless and replaceable but after 10 years it does not seem to be showing any wear.
Cheers, David Baillie

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Okay David, Those are the kind of numbers I am used to from growing up in Vermont. I forget that I had to actually see, and help stoke a Rocket Mass Heater before I could believe it either. The flu pipe was a 6" piece of galvanied single wall. The galvanizing was not discollored, so you knew it had never gotten very hot. I could have kept my hand on it the whole time. I guesse it was about 90F. Outside you could smell a very slight sweetish smell that reminded me of a maple evaporator but not exactly. He was burning some scrap 2x4s that he split up smaller than I would even split kindling. I guesse he had about 20 pounds in that bucket when he started. You couldn’t see any smoke. Supposedly there was some right when my friend lit it, but I wasn’t ouside right then. The house stayed warm all night. It got down to about 15F that night. Here in the Denver area they think thats a little cold. :grin: The coldest I’ve seen it here is -12F. I hope you get to see one of these for yourself sometime.
Rindert

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Hi Billy,
I sure would be interested.
Rindert

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c
Sorry it took a whgile to get some pics. We finally set up the oven in it’s final home. It still needs some paint in a few places.

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chicken legs…not quite done. Those are some tiny T-LUDS on the table in the back ground. And a metal-bucket-rocket stove in the far back.
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Much better after 425 F for a while.
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The oven box swivels on the bottom barrel. Both ends of the oven can be removed to make a directional heat exchanger. I have hopes of developing a steam powered fan to pull hot air through a food/coffee drying chamber. It may end up being our laundry drier???
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Jesse sorting firewood for the different stoves and ovens.
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I made this oven with a “self feed” and an ash tray. The ash tray also serves to feed air to the under side of the combustion chamber. But usually this is not needed since the down draft of the air through the fuel inlet keeps the fire from climbing out of the feed slot.
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At other times I have used fiberglass or mud to seal the barrels together. This time I bought 2 rolls of exhaust pipe wrap. It worked perfectly and looks much better. This one also has heavier steel for the gas manifolds. Earlier models were too efficient and caused cooking problems as the temps jumped rapidly (often exceeding 600 F). We added some mass to absorb some heat so it could serve as a heat generator/exchanger for an air space (highland greenhouse) in a place where fuel supply is short, but where there would also likely be an abundance of labor (to tend fires at night) . For exmples: Andes Mountains, or small scale Central/South American coffee farm…etc…

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It’s amazing how much you can cook on so little wood if you get a near-complete-combustion.

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We also built a plancha stove one day last week. I narrowed the plancha this time and extended it’s length. Also added some left over ceramic tile. Built this one on a heavy duty plastic pallet so it could be moved around with a fork lift if need be. The “sooted-up” tile above the combustion chanmer came from before the adjustments were made to the spacing under the plancha. Also, I still need to get a bigger pipe, this one is just a little too small for the size inlet I have. I will put a six inch pipe on that 4.75" clay pipe and extend it above the roofline. That should fix the soot problem.
Here’s Naomi cooking some hamburgers for supper.

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Used the firebrick liner from an old gas fireplace insert to cut out tiles for the firebox and the shelf around the outside of the stove.

This one probably belongs in another post, but the pics are on the same flash drive so I’ll stick them here.
Found a use for 345 old glass bottles today. Built a retaining wall in the new produce wash station.
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Capped the wall with a piece of hardi cement siding that we were going to use under the gravel in a new parking lot. The whole thing worked out well I think.
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The pipe is for the sink that will stand here when we get some gravel or wood chips on the floor.

There are about a dozen more projects lately, but I can’t find the pics. Have to find it later…

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I would love to see other projects. I wish that I lived closer to you for a visit.

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Yup, exactly my impression. They’re like race cars. They do fast, and full blast real good, but they don’t turn down or go slow very well at all.

And no worries about the time warp, okay? It gets us all.

Rindert

You’ll make it one of these days. Maybe we can do a woodgas get together down here sometime. Or carve out some time to come for our open house after we get it scheduled. Maybe I’ll just go withyou to Africa to teach or something…Anyway,

I hope to finish the UDIL-CIP soon. I remember you were working with sanitation in Rwanda.
(Urine Diversion Improved Latrine- Compost in Place) We’ll try to get some pics before it gets used.

:roll_eyes::grin:

The rocket chimmeney as a heat source helps with that a great deal, since you control temps by controlling the amount of fire anyway. As opposed to a regular old barrel stove with a big fire in a barrel where you have massive amounts of wood gasifying and combusting all at once. The rocket chimmeney limits that effect considerably…
I had thought to put a damper in the exhaust chimmeney, but am afraid of clogging the passage between the barrels. You can actually regulate temps pretty well with this higher-mass model, after you learn how to manage the fire. Like most woodstove cooking (even a little more), it’s an art as well as a science. So many factors----wood quality, humidity, temp, etc…
Limiting the amount of fuel available in the combustion chamber and also regulating the inflow of air does help with temp regulation. This one takes a few minutes longer to get to baking temps, but is much easier toregulate than other lower-mass models we have built. It would serve very well for a small scale bakery or heat source for a green house where you weren’t trying to fire it up and shut it down every little bit.

I really like it…You know what they say…Happy wife = Happy life…

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Go to the picture of Jesse sorting fire wood. You have two barrels with a 6" pipe connecting the two. Could you put holes in the 6" pipe and get a secondary burn?? TomC

Mr Tom,

Not sure.
But the basic goal of a rocket chimmeney is for all the tars and oils to be burned up by the time they reach the top of that chimmeney at that collar. So hopefully there would not be very much to burn at that point in the process. If there is something there, then it means the rocket effect is not happening completely enough.

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Rocket stoves are very similar to the Masonary heaters except that Masonary heaters have high mass to store the heat. I hope to build a Masonary heater with a built in bread oven someday. It is on my list of dream renovations for the old farmhouse. I so miss the wood gasification boiler I had at my last house. It is amazing how much heat a traditional wood stove wastes.

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Well since we are mostly STILL in the middle dead of space heating winter you sure put up some nice PRACTICAL-USE realistic home heating information David Bailllie.

The really nice thing about these MODERN secondary burning bulk woodstoves past their minimum of 70% to as high of 85% fuel-to-spaceheat efficiency is their wide range of wood fuels use flexibility.
You and I can fuel with large, small, medium, splits in all species. Dial in the heat needed with the fuel woods types and sizing. No special stick form; chunk form; pelleted form, needed. And these types ONLY able to fuel with their own designer fuel form!

In mine I routinely burn bundled up 5 to 15 mm sticks “harvested” out of the always accumulating homestead thinning/pruning/wind harvest pile.
Wifie loves accumulating woven reed and wooden splits garden baskets. Done their potting soil time and rotted out and I wood stove burn these too. I can and have burnt thrown-out and black molds damaged picture puzzles. Corrugated cardboard; always. Pasteboard packaging; always. Anything and all things wooden/paper broken, discarded, no longer usable. Tables, chairs, garden furniture.
Every year the wood shed floor accumulates blocks splitting strandie chips and bark chunks. I paper bag these up and wood stove these for heat too.
I have burnt tossed out, water and mold damaged books. “Pulp” fiction as the easiest to do. Hardbacks: tear the covers off. Roll an bind the center into log form so they can gap lay.
Every year my nusie wife disposes of the oldest of her patient and business files. Roll them up. Bind then and logs-like burn these in the heating season wood stove. Ashy pita fuel. But saves the professional shredding costs to then just land fill contribute-to-the-ages.

Comes from the air CO2 and grounds minerals. Recycled back for another growing go-around. Says I.

Yesterday, Sunday, wifie cleaned off one side porch the chickens tried to take over. Soiled cardboard boxes, and gifted to us paper-pulp egg cartons. Ha! And all of my saved holes worn pig skin leather gloves. Sigh. I went a wood stove step too far. Chicken shits makes strong corrosives burnt. And the leather gloves had much preservatives in them.

What you all rocket stove enthusiasts fail to understand is I DO rocket forced time and velocity daily for ~20 minutes from a cold start. Rapid use ~2 pounds of wood/paper fuels with all four of my stoves airs wide open to get my charbed established hot and driving. Get my 450 pound iron and brick stove up to good operating temperatures. 16 feet of double and triple walled chimney pulling up draft really strongly.
Then it is velocity/outputs cut back to a hot cruising 1 pound to 12 pounds of fuel wood and hour.
6000 to 72,000 BTU’s an hour into our 1300 square foot home.
250 heat needing days a year.
10 years on this current EPA certified stove. 50,000 working hours and only needing some sacrificial drop in stove bricks changed out.

I find those chasing the 85% efficiencies upward invariably are actually space heating with electricity, propane, natural gas. How do I know? In an actually people lived in space that 15% of chimney “waste” is needed to dehumidify a real house from people/pets exhaling/resperationing out pints a day, individually. Washing/showering in-house moisture contributions. Cooking moisture contributions in-house.
The bulk wood stove handles these all quietly, handily just as matter of course.

I see this same efficiency/numbers chasing bragdiosa on every social media platform.
My Toyota Camry gets 46 miles per gallon! Hiway cruise; yeah, maybe. Not overall driving sister of mine.
My 300 WinMag can push bullets out to 4000 feet per second! Yeah, sure brother-in-law. 15 pound capable only varmint bullets at the cost of barrel leade erosion.
My 2015 Ford F150 has a world-class beating EcoTech 2.7L V-6 engine! Yes sister of mine. DUAL exhaust turbo’s needed. Active continuously computer adjusting four cam engine. Demanding fully synthetic expensive motor oils then. For the l-o-n-g chain driven on each cam oil-pruurized phaser/timers. For the exhausr heat oil cooking turbo power boosters. My 24 year old Ford F150 with it’s “big” old last millennia push rod valved only one cam V-8 gets the same overall fuel used mileage and uses standard cheap dino lubricating oil. Yours will choke on any poor quality gasoline. Mine keep burbling along.

Real use numbers in all things are full cycle use numbers. Been sitting cold unused; through full use; then back down to cold sitting accumulated numbers. Year around use numbers. Cradle to grave numbers. Charletons, con-artists and the shallow minded use snap-shot, steady state numbers.

BillS, as you are finding true rural living is a demanding practical durable, long-use, simpler-is-better lifestyle.
Ignore those who do not live similar to you. Without similar values and goals.

tree-farmer Steve Unruh with min 88 inches rain a year. 122 inches in especially blessed years.

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I’ve linked to this page before but I just love this one.https://chimneysweeponline.com/wscomp8.htm
Mine is a pacific energy super 27. This year will be the first year I break into the 5th face cord of wood unless things get warmer fast. As I’m home more during the day this year I tend to keep things warmer. We used to make due with 3 face cords of hardwood and 1 and a bit of softwood but with kids we increased our burn rate.
Always a pleasure Steve.
Cheers, David Baillie

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Another really good one to refer folks to DavidB is:
www.woodheat.org
Out of eastern Canada I believe.
Once they responded to all of us “no hardwoods - fir/pine&spruce only” folks their information’s have become much better.

The best wood-for-poeple-living-inhome-heating comes from between 40 degrees latitude North and South imho.
Center of the world folks unless very high up Andes and central Africa just do not get the annually months/thousands of hours of needing experiences. They do know how to cooking stove though. Why they love their Rockets.

I will never say rocket stove, or respond to rocket stoveing ever again in my lifetime to anyone.
I actually know well tech-level limitations and tech-talk responsibility.

Geeks, techies, lab-rats, experimenter’s can all justify 999 failures out of 1000 attempts as pushing the boundaries of endeavors/knowledge’s.
The actual mathing Degreed Herr Doctor Professor lab-rats are very good at finding the 100% theoretical possibility limits. VERY poor at achieving anything usable in real life.
The Design engineers very good at responding to manufactures/investors/promoters/marketers demands. Equally terrible most often putting out real world DURABLE, LONG LIFED units.

The real world usable is in the actual field make-it-work engineers and operators. No degrees required. Very little maths. Just decades and decades of seen-it, do-it for thousands and thousands of hours, experiences.

I am coming to believe that social forum media is a wasted effort.
Books, blogging is a take it or leave it; shut-up and walk away, maybe, better way. Certainly much less frustrating.
ChrisKY. I was wrong. Apologies man.
tree-farmer Steve Unruh

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great point Steve. The purpose of the stove is more than just heat usually. You mention one I had not thought of; dehumidification. Reminds me of our time in TN. We had no electricity there. It was swelteringly hot and humid with little breeze. We found that even at 102 f it was worth building a small fire int he cookstove to 1, heat water, but mostly to dry the air some. It actually felt cooler with the fire than without.

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“Ever tried. Ever failed. No matter. Try Again. Fail again. Fail better.”
~ Samuel Beckett
“Our greatest glory is not in never falling but in rising every time we fall.”
~ Confucius
“Great success is built on failure, frustration, even catastrophy.”
~ Sumner Redstone
“Failing is one of the greatest arts in the world. One fails toward success.” ~ Charles Kettering
“Failure provides the opportunity to begin again, more intelligently.” ~ Henry Ford
“The fastest way to succeed is to double your failure rate.” ~ Thomas Watson Sr.
“Only those who dare to fail greatly can achieve greatly.”
~ Robert F. Kennedy
“I’ve missed more than 9000 shots in my career.
I’ve lost almost 300 games
26 times I’ve been trusted to take the game winning shot … and missed.
I’ve failed over and over and over again in my life. That is why I succeed.”
~ Michael Jordan
“I never learned a thing from a tournament I won.”
~ Bobby Jones
“Our achievements speak for themselves.
What we have to keep track of are our failures, discouragements, and doubts.
We tend to forget the past difficulties, the many false starts, and the painful groping.
We see our past achievements as the end result of a clean forward thrust,
and our present difficulties as signs of decline and decay.”
~ Eric Hoffer
“The essential part of creativity is not being afraid to fail.”
~ Edwin Land
Steve,
I admire you for your work and tenasity, but, I think it´s not a shame to fail; it´s another way in witch human mind and body, bonded together are forced to find solutions.
I thinkI have learned much from my failures, many have also. As an anaesthesiologist (now retired) I could no fail, It would have been a cathastrofy, has a stove and kiln builder, I can fail and learn.
Those are my thoughts

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I have been mullingover this quote since it posted the other day. I think it is my new favorite quote. Probably because it helps me justify so many otherwise-negative-occurances in my life…lol

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I remember something my chemistry teacher in high school said. “You learn something from your mistakes, but you learn more from your sucesses” After 34 years I think he is right.
Rindert

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To be sure. The goal isn’t the failure.

I love these quotes, but at the end of the day it’s not about Michael Jordan missing 9000 shots, it’s about his willingness to not allow his missing 9000 shots to keep him from becoming the best basketball player in history.

Though, I do think far too many people just use the idea as an excuse to be mediocre and not try at all because, you know, “Oh well, nobody’s perfect right? We all make mistakes, why eve try?” Sad way to live I guess.

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o gosh, why won’t you buy a gas stove. They’re cheap and effective.

Somebody please explain me your philosophy

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