Indoor rocket stove without exterior venting - is it possible?

total newbie here. Is it possible to have a Rocket stove used indoors (think workshop that is used everyday) without exterior venting? Plan to get CO detector, etc, but cannot at this time vent it externally. What are the risks? I camp outdoors for an average of 6-8 wks a year, so minor smoke inhalation etc is nothing new. but would prefer not to poison myself
Thanks
MSotherden

M Sotherden wrote:total newbie here. Is it possible to have a Rocket stove used indoors (think workshop that is used everyday) without exterior venting? Plan to get CO detector, etc, but cannot at this time vent it externally. What are the risks? I camp outdoors for an average of 6-8 wks a year, so minor smoke inhalation etc is nothing new. but would prefer not to poison myself

I wouldn't do it. CO and particulates are not the only problem (minimum as they are in an RMH they are still there and CO is cumulative). You will need incoming oxygen and you need to remember you can't do much breathing CO2 either (and you generate a lot of CO2). So considering you need to have some place for oxygen to enter... run a pipe out the same for exhaust. Even a door open a bit... use some aluminium drier ducting, the exhaust should be cool enough by that point anyway. When you close the door just kick it back inside. The majority of the heat coming from the heater is radiant, you are not heating the air really, just so long as your back can "see" the heater you will feel warm. The other reason to exhaust is water content, if you exhaust inside, everything will be wet all the time.... just check out an rv with a propane stove when it's cool. The general thing is Oxygen and Carbohydrates in and CO2 and H2O out. You don't have to have a permanent exhaust set up, but use something.

M Sotherden wrote:total newbie here. Is it possible to have a Rocket stove used indoors (think workshop that is used everyday) without exterior venting? Plan to get CO detector, etc, but cannot at this time vent it externally. What are the risks? I camp outdoors for an average of 6-8 wks a year, so minor smoke inhalation etc is nothing new. but would prefer not to poison myself
Thanks
MSotherden

Dearest Permifriends,

Carbon Dioxide (CO2) is not a poison to animals. It WILL KILL you however by excluding Oxygen (O2) from you. A CO detector is a Carbon Monoxide detector and will not tell you if CO2 is present.

If you burn any hydrocarbon fuel in an enclosed area you need to exhaust it outside. As your room fills with CO2 the air in the room will be forced up and the CO2 is heavier and will fill the room from the bottom up.

You will need to heat with electric or solar if you can't exhaust hydrocarbon burn to the outside of your enclosed space.

For a roof exhaust why not continue the mass to the ceiling? In northern Maine one family I called on built an octagon log cabin with a river rock mass fire place in the center. The top of the rock mass made the center ring for holding the rafters. All of the heat radiating from the mass was then in the living space instead of being exposed to the outside as in a fireplace through an outside wall.

Thank you to all guys/gals!

Not worried about venting the water - really - not enough humidity is actually an issue where I live during the winter months, and we already run a humidifier 24/7... so unless its a LOT of water, that doesn't concern me a bit. I didn't realise that the outgoing temp would be cool enough to use a metal dryer tube/hose/vent... and yes, that will work fine actually because that would be "normal" to have coming out of this structure (or worst case scenario, shoved out the back window wrapped in some insulation so that the window isn't leaking a ton of 20 degree air back into the area I'm trying to heat.

Thank you folks so much!

MSotherden

M Sotherden wrote:Thank you to all guys/gals!

Not worried about venting the water - really - not enough humidity is actually an issue where I live during the winter months, and we already run a humidifier 24/7... so unless its a LOT of water, that doesn't concern me a bit.

Think of about 10lb of water for every 10lbs of wood burned.... an imperial gallon. But the CO2 is much higher it would be higher than by weight than the wood put in (who knew air was so heavy).

Wood is a hydrocarbon. There is about twice as many hydrogen atoms as carbon, but carbon weighs 12 times as much. Oxygen weighs 16 times as much a hydrogen. So for an amount of wood (100%) the hydrogen would be about 15% (1/7) The oxygen added to that would be 8x more (2 H per O) or 135% all together. The Carbon from the same weight of wood would use twice as much oxygen (240%) plus the 85% Carbon... so the CO2 generated by any given amount of wood would weigh more than 3 times as much. Considering only about 22% of the air is oxygen to begin with and that the CO2 takes it's place... how long would it take for the oxygen level to get below breathable? (or for the fire to starve itself?)

I didn't realise that the outgoing temp would be cool enough to use a metal dryer tube/hose/vent... and yes, that will work fine actually because that would be "normal" to have coming out of this structure (or worst case scenario, shoved out the back window wrapped in some insulation so that the window isn't leaking a ton of 20 degree air back into the area I'm trying to heat.

I wouldn't worry too much about sealing the exhaust. You must have incoming air.... at least as much as the exhaust going out, but probably a lot more (you do want to breath). You are not trying to heat the air anyway. You are trying to heat you and your tools and the materials you are working on. You do not want a sealed building or anything close to it. A cardboard reflector (covered with foil?) over your work area to reflect the radiant heat from your heater to what you are working on may help though.

Keeping the fingers warm will be the hardest part. The body is a system and tries to be self regulating. If your core is warm enough, your body will start to use your extremities (like fingers) to cool your blood off. After about 45min. your fingers will be fine if your core is a little over warm. I use old sock cuffs to cover my wrists and the back of my hand (so my fingers still work) leaving a palms bare to put my fingers against when not in use. This works much better than any gloves I have tried ( I work outside, so I have tried lots). After about 45 min. my fingers no longer feel cold. Whatever material you are handling will of course effect your fingers too.

One more time, you do want air holes in your building.... You do not want a sealed building. For health, you should expect to wear warm clothes in layers so you can keep your core at the right temperature. You do want your body and the things you are working on line of sight to your heater so they can be warmed primarily by radiation. Walls are best treated to reflect radiation back inside.

my only thought would be to design it so that your exhaust gasses are relativity cool and use an inline fan to vent it out a window. say take a 2x8 and cut a 6" hole that can sit in the window frame and let you shut the window down onto it. paint it to match the exterior and no one will probably ever notice might even look like a portable dryer venting from a window.

the inline fan should negate the need for a vertical stack to make the system flow.

so picking up on this thread... My question would be can you test run the heater indoors before getting the outside vent installed?  If I open a door and crack a garage door I should get a good convection.  Just really want to test my design before I've built up the mass around the barrel any further.  

Am I crazy?
Jen

You can try it, but be prepared that everything will smell like smoke in the test area. Rocket stoves are efficient, but they have to get to optimum burning temperature first and the exhaust still will not be the same as burning for example propane (there are ventless propane heaters).
I would not do it myself.

Hi Jen;
I agree with Christobal, lighting a first burn indoors with no chimney would be no fun at all.

What design rocket have you created?
A standard J-Tube that follows building guidelines will work every time.
In fact, in some cases, they need a mass to draft properly.

Tell us what you have built, maybe even show us some photos.
And meanwhile, get a chimney poked through the roof... just saying...

Jen Siegrist wrote:so picking up on this thread... My question would be can you test run the heater indoors before getting the outside vent installed?  If I open a door and crack a garage door I should get a good convection.  Just really want to test my design before I've built up the mass around the barrel any further.  Jen

Hey Jen. Cristobal and Thomas have been very circumspect and polite, but pointing you in the right direction.

So here are my not-so-delicate thoughts FWIW.

Any combustion system without serious, positive venting is a very bad idea inside a habitation. Combustion byproducts are potentially dangerous to human life and health (CO, CO2 ...), and excessive water vapour is potentially a source of trouble for the buildings we live in, encouraging molds that degrade air quality and can create serious allergens -- and are damn hard to get rid of once established in the walls and every cold, moist nook and cranny.

With every wood fired system I've ever used, the chimney is an integral part of the combustion system, not just a dryer vent. The chimney, if long enough, keeps the flow going -- forming a steady vacuum that lets you regulate the burn on the front end, and prevent dangerous backdrafts.

You can vent a tall chimney out a window when experimenting (I've done this many times). But for safety you must have one!

(End of sermon, haha.)

so let me see if I can do this and attach photos through yesterday's progress.  Here's the specs:
I'm dealing with a poured concrete original garage floor that was never brought up to level.  
The whole house is single story on a slab
The renter before the house was put up for sale put... wait for it: bean bag pellets by the crap load in the attic uncontained as insulation along with every piece of junk he could find apparently.  For that reason, I'm venting straight out the wall and then building the insulated chimney outside.  

The build is a J tube 16.3 - 24.5 - 9 (separate heat riser to bring to height of 46" with 2.5" gap to the top of the top barrel)  As I said, it was the original garage floor so it was poured to drain out.  To get a level base for the build before the firebox: clay stabilized perlite 1.5" topped with 1/2" fiberrock board for a nice level surface to work with.  The firebricks are rated at 2600 laid with clay slip to form the J in an aperture of 4 3/4"x6 5/8" throughout.  That is then surrounded by regular red brick to raise the base just an inch from the bottom of the heat riser.   6' galvanized pipe for the system that gains incline as it heads up n out the back. The run is approximately 24' after all laid out with the exit through the wall which is Not load barring except for itself? Again the renters did crazy things.  The exit vent pipe is insulated 2" all the way around with cast aircrete (to be sealed against water not fire) for the depth of the hole even though it's mostly brick.    The barrels are food grade cleaned of their paint.  The mass is fieldstone,cob, sand, and pea gravel to be topped with scrap granite strips.

Also, it may be redundant but I have a lot of tile as well so I'm going to tile the wall that isn't brick beside the fire feed and barrels.  I have my feed tube inside that corner instead of on the outside is the only thing I can think of as being kinda different, really.  I have the clamps and heat gasket for the barrel connection so I can pop off to clean/rebuild if my riser fails but it's in  the form for another 2 days before I rigidize with water glass so I can't really give ya pics on that.  Nearly all of the supplies came from this property or I had hoarded (I hoard building supplies, I admit) over the years.  

Okay!  Lemme have it!  What didn't I think of.  Or what did I neglect to tell you?  

OH! the barrel sits 10" away from the wall - before the tile goes up.  I made sure and read the ohio building codes regarding masonry And adobe heaters.

Thank you guys so much for jumping in.  I've been researching and gathering for the last month. Watching all the videos.  Purchased the plans from Ernie & Erica then did my own twist on it.

Jen

Jen Siegrist wrote:The renter before the house was put up for sale put... wait for it: bean bag pellets by the crap load in the attic uncontained as insulation along with every piece of junk he could find apparently.  For that reason, I'm venting straight out the wall and then building the insulated chimney outside.  

Ah! A real chimney! Well that covers my rant.

The RMH wizards will have to comment on the technical details.

Keep us in the loop. It's an interesting project.

Okay... starting over.  One thing I have learned from the initial overthinking is that it's easy to accept a bad design because you can just take apart and reuse the materials (given you have time).  I only had it half built before I determined it was not making me happy but the real lesson there was: Don't try to build this in a panic!  

So I'm changing it up.  I've decided against tiling the wall behind the barrel, moved where the barrel will be, changed the system to a strat chamber, and I never could get that steel tube out of the cast perlite riser... but I'm going to give lining it with ceramic fiber blanket and see how well that goes with insulating the steel tube inside and out.  I'll replace that riser before next season anyway.  It's just that I need heat in this house (incidentally my on demand hot water heating is having issues too, so that's also cold).  This house will be the death of me.                                          

still a 6" throughout j-tube with 55 gallon drums (though I'm not sure how necessary after binging stove chat on repeat, thanks Matty!)

So where I'm going now is to address the poor insulation in this house (and the incredibly annoying, 3am rock n roll blasting, hot-rod wrenching neighbor who breaks my sleep) is to cob my interior walls.  I stumbled into some of Chris's videos and dove deep on that one.  The adjoining brick wall in this pic is, in fact not brick veneer, but a full brick wall inside of the original exterior wall.  I have the exit, still going out that wall, but have an interior "juice box" pipe planned to run to the far end of the strat bench at an angle to catch the cooled gases.  Am I correct in thinking that I can use the heat from the barrel, and to some degree, a portion of the angled pipe in the warmer "altitudes" of the chamber to facilitate draft?  I have the run on the chamber mapped out to 10' and 5' (L) and 36" wide with the interior pipe/exhaust draw from the far end at a 19" ascension span from cool bottom to warm exit.  Thoughts?

As it is finally warming back up outside, I'm able to get out and work a bit, allowing for the very slow curing time of the cob and fieldstone in courses.  I'm slow to progress but I think that's a good thing in this instance!  As to the cob, I've found that mixing it with wheat paste instead of water has made is chocolate mousse smooth and sticky but I'm only laying it on 1/8" thick at a time on the walls... Mud mentioned something about linseed oil (i believe it was) going rancid and it occurred to me the same could be true of the wheat paste if one weren't careful?  It does seem to make it just a touch stickier in the cob, but what do you think about that mixed in for the cob on the fieldstone of the bench?  Good idea/Bad idea/"What is wrong with you?"/no idea.

Still workin' it all out.  You'll know I'm nutz when I tell you that I have become accustomed to using Paul/Chris/Matt/Erica and Ernie/and frankly, Neil DeGrasse Tyson videos as my every day, all day soundscape.  I've been lulled to sleep, even, by their dulcet tones... (maybe that's just creepy?)

Jen

OOH! and now I'm considering how to incorporate a hinged top on the bench anchored into the studs or brick wall for cleanout.  Maybe sealed with heat gasket on a ceramic fiber board and tiled top? Need to work that out too.  Little by little.