Scott Clark

Glenn Herbert wrote:Okay, large volume for a garage, modest insulation considering the climate. You presumably don't want a long bench for a radiator, as there is usually not a lot of sitting around in a garage. Do you want to keep it heated at least modestly full time, or is your desire mostly for fast heat while you are working in the space?

My first thought would be a 6" batch box with a tall narrow bell for mass/radiator, located as close to the middle of the space as fits with your intended usage patterns. This would give a 2' to 3' wide x 4' to 6' long footprint, depending on exact configuration. If you will often want to make it warmer for short periods, I would use a standard RMH barrel over the heat riser, followed by a bell next to it. This will take a bit more space, but increase the versatility. The batch box gives a long burn time without frequent tending, which would be important in a space where you are not spending hours at a time.

Look for "peterberg batch box" in the forums at donkey32.proboards.com for dimensions and details about the batch box style.

This is essentially what I built in my garage...6" standard rocket core with a water heater tank as a bell. Didn't have room for a bench, so it's designed to just extract as much heat as possible. It's a very powerful heater. It can raise the temp in my (very poorly insulated) garage about 10* an hour. When it's below freezing out, it maxes out at about 70*F...at which point I'm melting the snow off the roof lol. Using a fan to circulate the air around the garage helps, but if you had a standard ceiling with any kind of insulation it wouldn't need to be very big. It was kind of a big project...it required a surprising array of my skill set. Very happy with it though...I got a ton of heat in my garage burning scrap wood and stuff people would usually toss in their burn pile, so I got heat for "free". Here's what it looks like right now...

Wow...that's a 500 gallon tank (!). Would make a hell of a bell if you had room for it...if you had room for it lol. I made a bell out of an old 50 gallon water heater (seen behind the barrel). The one you posted would have 10 times the internal volume. Cut it in half, and you've still got five time the volume. I would think the biggest problem would run into would just be moving it around and working on it...those things are usually set into place with a small crane mounted to a big flatbed truck.



The rounded top shouldn't have any effect on function I wouldn't think. The gasses inside should still stratify as they would if it was flat.

I cut my wood pretty short...about 12" or so (for the most part). I know a lot of folks have an interest in getting longer burn times out of a rocket stove, but it seems like you might be kind of fighting against the nature of the beast... There's more to it than just having longer pieces of wood (IMO, anyway)...it seems like as the wood burns I have to do a fair amount of "adjusting" it's position in the feed tube to get the airflow just right, in addition to adding more wood. Building a batch box instead of a J tube could be a more workable solution... But, you never know until you try I...build a prototype, and share your results, I'm sure a lot of people would be interested to see if it works.

Don't try and burn wood that's too long--if it gets jammed up on another piece of wood, the bottom can burn out, allowing the now top heavy (and flaming) remains to tip over onto your floor. I cut all my wood to about a foot in length, though I know others run wood longer than that.
Don't install it too close to combustibles (or use a heat shield). Follow NFPA guidelines for an unrated wood stove, and you should be fine.
Otherwise for the most part it's I think it's about like running a regular wood stove...use common sense that would be appropriate for something that gets really hot. I keep my welding gloves handy for when I have to re-arrange the wood in the feed tube.

Barbara Du Mond wrote: However, we are concerned about air quality and don't want to be adding to global warming via our heating system if at all possible. We are located in the mountains between the ocean and SF bay and have winter spare the air days when no wood burning is allowed (with exceptions for homes that are only heated by wood). We have more than enough wood on our lot, and need to do additional thinning to reduce fire load. So I'm hoping that someone can tell me what gasses are given off from the RMH, especially how much carbon and volatile gasses are released into the atmosphere. I'm open to other ideas about how to heat the space as well.

One of the things I like about burning wood for heat is you're releasing carbon back to the atmosphere that's been stored for what, 20 to 50 years maybe? Much preferred to the eons old carbon being pulled out of the ground, IMO... And if you're burning fuels off the property, you'll release far fewer pollutants than if they were consumed in a wild fire...every year we have to live through a smoke filled valley during fire season. A forest fire is not exactly a model of efficiency lol. And as others have said, a properly running rocket stove won't smoke at all once it's up to speed...the smoke is fully consumed by the fire. Even carbon monoxide should be pretty well burned up.

It sounds like your best bet might just be to put another pellet stove out there... I have three pellet stoves to heat my house, but the garage is heated with a massless rocket stove. I actually have another pellet stove I could have installed out there, but I wanted to burn wood because I can basically get it for free. A pellet stove takes up a lot less room than a rocket stove, if space is an issue. They also have much closer installation clearances (many of them only need a few inches of clearance from a combustible wall). They can also be run off a thermostat, and don't have to be fed every half an hour like a rocket stove. Set on low burn, my big Avalon might be able to squeeze two days out of a full hopper (about 80 pounds of pellets). That's with a constant burn that never shuts off. But, since it can run on a thermostat, that may not even be necessary.
Anyway, just a thought...rocket stove isn't the answer to every heating situation, but you may definitely find one it's a good fit for .

Jay C. White Cloud wrote:Great post Scott, and it really speaks to this topic...

I have lived in both "east and west" coast mindsets of burning wood...My view is I would rather burn Conifers (especially with a masonry heater type wood burning device)...and only have hard woods for cooking...My grandmother, even being from the Ozarks, preferred Pine and Cedars for heating...and hardwoods for cooking.

Regards,

j

Yea, it's really interesting to see the different perspectives people have just based on where they live... I'm going to try and clear my 5 acres of all the deadfall in the spring/summer and process it for rocket fuel, which has an added bonus--fuel reduction across the property in case of a forest fire. In 2012 the Sawtooth Fire came within a mile of my house (it was in the evacuation zone). I've got Ponderosas all over the place, and at least two dead ones I need to cut down (and make into fire wood). Rocket stove should love all of it.
This will probably make some of the folks back east laugh... In this big pile of scrap wood I got for free, there was a single oak plank...it was grey and weathered and I didn't recognize it until I cut it. I handed it to my kids so they could see what a fresh cut piece of oak smelled like...they all wanted to keep a piece like it was something exotic from some foreign land lol. I have about 25 pallets out back I need to dismantle, and in them I found a single one made entirely out of oak...I put it in the woodshed, and I'm going to take it apart and use the wood for something other than fuel. The beams are these nice thick pieces, which seem like they should be useful for *something*. Maybe carve wooden swords or something. Next summer I promised my kids we'd try and make a Viking shield (we do some nerdy projects like that)...we'll forge the boss from a piece of steel in our pit forge, and I figured the oak planks from that pallet would work just dandy for the rest of it. So much better than pine .

Interesting...the idea of burning hardwood is almost completely foreign to me lol. Around here oak is almost unheard of...there's some maples in town, but out where I live it's all pine...with some fir and aspen mixed in. And the occasional random apple tree. If you run into a piece of oak, it's probably part of a piece of furniture . Everything I've run though the rocket stove so far has probably been some variety of pine...not knowing what a piece of hardwood burns like, I guess I don't know what I'm missing lol. It does burn pretty fast, but what the heck...all my wood so far has been free, so I can't really complain about how fast it burns. It's hot and clean too...inside of the heat riser is nice and white.

allen lumley wrote:YES ! Candles are a source of Soot and Nano Soot production that is hard for most people to understand as more than an intellectual exercise !

Frequent burning of candles inside a house comes with a guarantee that those spider webs up by the ceiling that you never saw before now will
be outlined in black !

Frequent use of (especially of petroleum based candles) candles will highlight this Arachnid Artwork faster that escaping smoke form well tuned
heating appliances !

The Important thing in duplicating this experiment is to use a used candle with a previously burned/carbonized wick !

Yes I tried it both ways, the used candle always works best, the Candles in my '' Oops, the power just went out '' are all pre-lite, with Carbonized
wicks! This is where I keep a stash of Empty Lighters that can still throw a hot spark !

After I get The House-Core lit- that is soon enough to trim wicks for longevity, the shorter the wick the less smoke particles I THINK

For the Good Of the Craft ! Big AL !

Yep...back when I was an HVAC tech, once in a while we'd get someone calling complaining about their (insert whatever heating appliance here) making soot in their house. First question we'd always ask was...
"Do you burn a lot of candles?"
The answer was yes almost 100% of the time. It was only an extremely rare case when they had soot in the house that wasn't caused by them.

This has been a really interesting read... I've got 5 acres with a lot of Ponderosa Pines on it, and next summer I'm going to collect all the dead fall from the property and process it for fuel. I'm lucky enough that around here there's so much waste wood (and free scrap if you scrounge) growing trees just for fuel probably won't be necessary any time soon. I figure once I get all my own dead fall cleaned up, I can always go collect it from public land around here if need be.
Fun to read about other options though!