Now that transaction fee storm has passed I'm back to heating my living space primarily with wood in a rocket mass heater instead of Asics. Wood is burned in the small firebox and heat radiates from the barrel warming the space quickly while the fire burns. image As the exhaust gasses make their way to the chimney, they pass through ductwork in a plywood box filled with pea gravel. image The majority of the heat from the exhaust is transfered to the gravel before exiting up the chimney. By the time the gases exit the box, they are cool enough for me to put my hand on the chimney pipe. image After the fire burns out, the heat absorbed by the pea gravel slowly radiates out into the living space until the next fire is burned and the gravel is recharged with heat once again. I built this rocket mass heater for a fraction of the cost of a wood burning insert, with no special tools, materials, or skills. image It has been an unusually warm November and December here at the homestead. Normally we have to start burning wood in the rocket mass heater early November to stay comfortable but this year, the bitcoin mining dehydrator was enough to stay warm and do some food preservation simultaneously. Transaction fees started climbing and I was shocked to see the most efficient miner I had approaching break even at my electric rate. I didn't have the circuit to run it wired yet but this bump in fees was the motivation I needed to get the miner hashing. Coincidentally, the weather also started to get colder finally so getting the miner up and running was a win/win. image It successfully kept us and our guests warm through the holidays, even earning some Bitcoin beyond the cost of power at times, all while allowing us to save our firewood. image We did have to fire up the rocket mass heater a handful of times, but so far we've burned less than half the amount of wood compared to previous years. This is thanks to the combination of the warm weather, and high transaction fees allowing us to stay warm with heavily subsidized electric heat. image This might be the first winter we make it through with wood leftover for the next year, typically I'm scrounging for the last couple weeks. #permaculture #permies #homesteading #selfsovereignty #meshtadel #rocketmassheater #woodburner #bitcoin #bitcoinmining #plebminer #rmh #grownostr View quoted note →

Replies (38)

I basically followed the rocket mass heaters builders guide book exactly and it has been working flawlessly with only regular cleaning necessary. I've made a few minor upgrades over the years, like using a fiberglass blanket instead of rock wool for the riser insulation. I plan on converting it to a batch box burn chamber eventually.
There is a riser inside the barrel which traps the smoke from the fire inside. This forces the smoke to combust, that combustion plus the surface area of the barrel rapidly cooling the gasses creates a pump-like action forcing the exhaust horizontally. There is a slight incline on all the ductwork too. Additionally, by designing the final exit towards the chimney to be close to the barrel, it gets heated and creates an additional draft. This heater drafts really well too because the chimney is in the center of the house so it's always warmer than the outside temperature. There's a lot of factors to consider when trying to figure out how much horizontal duct can be supported by the system at various sizes of ducting so it takes a little bit of figuring and testing. That's why I built it in stages. I'm confident after using it for several years that I could run even more horizontal duct if I had space for it.
The size of the firebox is very important. I've seen RMH builds that have made the firebox too large and it wouldn't draft without a booster fan. This is one of the downsides to RMH. They require more feeding or need to be very large to heat large spaces or large masses. Batch box designs are possible but I've heard it's challenging to get right without experience with standard j tube designs.
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nobody 2 years ago
Pretty amazing system. I dream of adding this to our cabin when we get out of the village here in the next year or two. Sips firewood versus conventional wood burning fireplaces. I initially saw this design on Fouch Family Off Grid on YouTube
It took a few weeks, I built the core outside first, tested it, dismantled it, rebuilt it inside, tested it, built the ductwork, tested it, too it apart, built the box and rebuilt the ductwork, filled it with gravel (this was the most labor intensive part, took a friend and I several hours hauling gravel), then I made the finishing stuff so it was more of a process than a self contained project.
I saw fouch build theirs too! Because they used cob it they were able to save a lot of space and still get the same heat capacity from the mass.
Nice work, Rev! The setup reminds me of the old Czech kitchen stoves (Austria, Bavaria had the same ones - kachelofen). They usually build a stove top over the fire for cooking & tile up the rest. And mainly, build a day bed of sort and benches around the ducts. It's famously a very popular lazy spot in the house in the winters - warm, and easy access to the stove top goulash/stew :-)
Jim Smij's avatar
Jim Smij 2 years ago
I think I first saw a rmh on Paul Wheaton's youtube years ago. I stopped following the fouchs after their bashing of Paul... but anyway... the Rev here is an inspiration!!
This looks like the exact same concept except what I'm working with is way more hillbilly... Very nice examples, if I ever build a house I would probably design this sort heater into it.
Have you been to Wheaton Labs in Montana? I've known a few people that have also attended events there, several years back now, and echoed similar criticism as Fouch. I've never been there myself, maybe I'll find my way there one day. I think Fouch stopped making videos pretty shortly after their critique of Paul Wheaton for what it's worth.
PaddleManJoe's avatar
PaddleManJoe 2 years ago
Is it hard to scrape the ash out of that tight little J-Box?
brah's avatar
brah 2 years ago
Yo for some reason I thought the rocket mass heaters were like a conspiracy theory or something- I stumbled on reading about them last year and they seem much more efficient than wood stoves but I’ve never seen one in real life They burn less would and radiate heat longer but at lower temps than a wood stove right? Very cool
It's the real deal for sure. I burn 1/3rd the wood my neighbor does and he still supplements with propane. Also, I can burn essentially any punky or low btu wood and still get a lot out of it. I'm currently burning some dead standing as that's got mushrooms growing out of it.
Swan Tea's avatar
Swan Tea 2 years ago
Wow. So cool. I love Nostr people, so resourceful.
Here is a compilation of all my favorite mining notes from the last year. I guess use Bitcoin miners in almost every way I can think of. Sous-Vide Bitcoin Mining Hot Water Heater, featuring canola oil as the dielectric fluid. Hashing Space Heaters for Local Plebs View quoted note → Hot water heater with canola oil View quoted note → Direct DC with grid-tie backup proof of concept View quoted note → Clothes Dryer v2 View quoted note → Dehydrator View quoted note → Cannabis heater View quoted note → Cannabis Dryer View quoted note → Solar mining View quoted note → Maple Syrup Miner v1 (still need to make the v2 note) View quoted note → Hash while the fees shine View quoted note → #bitcoin #bitcoinmining #plebminer #homesteading #permaculture
rev.hodl's avatar rev.hodl
Cooking hash-vide style rabbit ramen with Bitcoin mining hot water heater The second meal cooked in the Bitcoin mining hot water heater is rabbit ramen soup. Rabbit grown and harvested right here at the homestead, along with these other ingredients from the homestead rabbit stock, garlic, and finally golden oyster mushrooms dehydrated with a Bitcoin miner. Soy sauce, rice vinegar, lemon, sesame oil, Japanese seven spice, salt, pepper, butter. All ingredients went into a silicone bag and submerged in the hot canola oil tank of the bitcoin mining hot water heater for 3 days. Hard to beat mining Bitcoin, heating water, and cooking food all at the same time. I can get the water up to 150f out of the tap with only 1500w of power consumption for the total system, miner, pumps, and all! Another super cool aspect of this mining setup is that it runs on 110v power instead of 220v. Not having access to a 220v circuit is often a limiting factor for pleb miners, especially when these sorts of applications don't always require so much power. By modifying the apw12 PSU and making a custom power cord, now I can plug the miner into an existing 110v circuit. It cost less than $20 to do the modification on the PSU plus using a modified apw12 vs a Loki + apw3++ allows for voltage attenuation and higher total power output. #permaculture #permies #homesteading #meshtadel #bitcoin #bitcoinmining #plebminer #homeminer #sousvide #rabbit #ramen #foodstr #stackingfunctions #doublespendenergy View quoted note →
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