Building code compliant prefabricated rocket stove, safety tested

Thekla McDaniels wrote:Well, if everyone who thinks they'll wait for the next one would buy the current one and start saving money, maybe that would speed the R&D, without you having to put a lot of time into a kickstart campaign, again, I'm cheering for your success.

Chris Holcombe wrote:The heater looks really interesting but I remembered that Oregon won't let me install anything that isn't EPA compliant :-/. There was a wood stove here before we moved in but part of the mortgage  agreement required the non epa stove to be certified destroyed or I would be denied a mortgage. I saw one of the previous posts saying you were thinking about epa testing. Update this thread if you do and you'll have another customer

Rob Read wrote:Hi Sky,

I don't know what your base price per unit is currently is on your website (still can't access it from my location for some reason) - but if kickstarter supporters got a bit of a savings on buying EPA approved ones, I'm sure you'd have no problem. I'd support the kickstarter to get a bit of a price deal - plus the value of EPA approval, which it sounds like for some states is mandatory.

You are so far along with the proof of concept, and already selling non-EPA approved units - and you could add stretch goals for the 2.0 model's R&D.

Sky Huddleston wrote:

The base price for everything is 1500 dollars (shipping not included). However we could give a discount of 1500 for any kickstarter supporters as EPA certified ones will include the insulation and their base price will be 1800 dollars.

Thekla McDaniels wrote:

Sky Huddleston wrote:

The base price for everything is 1500 dollars (shipping not included). However we could give a discount of 1500 for any kickstarter supporters as EPA certified ones will include the insulation and their base price will be 1800 dollars.

Do you mean a discount of $300,  bringing the price of the $1800 epa model to $1500 for backers?

Did I read you right?  Though I can be kind of a hair splitter, I don't mean to be nit picky, I just want to understand.

It seems like a better bet for a kickstart campaign than the other idea, half the price, probably a shorter wait time.  I guess epa rating is a very meaningful to mass culture, building codes and so forth.  It's kind of beside the point for rocket stoves, but the masses don't understand rocket stoves.  But if this goes forward, they will.

If the exhaust tubing is run through a cob or other masonry "bench" structure and then out the wall, would you still get some of the benefits of a regular RMH installation in terms of long term heat storage and dissipation?  Or would there not be enough heat storage?

Keith Kuhnsman wrote:?

If the exhaust tubing is run through a cob or other masonry "bench" structure and then out the wall, would you still get some of the benefits of a regular RMH installation in terms of long term heat storage and dissipation?  Or would there not be enough heat storage?

A hybrid, yes, with some issues to work out, but that may make it feasible.

Thanks for your thoughts!

Happy trails.

Keith Kuhnsman wrote:Learning newbie question here, so tell me where I go wrong...

I also am in an area driven by adherence to building codes.  Montgomery County, MD: "progressive " to the point of stifling anything not in the party manual.

The stove itself is code compliant and freestanding, yes?  Also, like a regular stove it will give off a good bit of direct heat to warm space up fast if needed, right?

If the exhaust tubing is run through a cob or other masonry "bench" structure and then out the wall, would you still get some of the benefits of a regular RMH installation in terms of long term heat storage and dissipation?  Or would there not be enough heat storage?

A hybrid, yes, with some issues to work out, but that may make it feasible.

Thanks for your thoughts!

Happy trails.

Dean Howard wrote:I'm jumping in kind of late, so forgive me if things have been covered already...
I'm impressed with your knowledge and fine design.  For those of us who like the traditional RMH, we want low exit temps, meaning things have stayed in the building, i.e.; radiated barrel heat, heat storage in a bench, etc.
1)  What is the expected average temp leaving your stove, as it is presently designed?...and
2)  How much chimney air can you push?  In other words... some stoves need the draw of the chimney to work.... or  Can I go straight out the wall like a pellet stove?
3)  What size pipe is exiting your stove?

So you'll know... I presently have a Wise-way, gravity-fed, non-electric Pellet Stove, which works marginally well at my 7,000ft altitude and present piping.  I like the idea of multiple fuels, no electricity, and the extra "engine" of the RMH to push the exhaust out.

Thanks

Michael Heath wrote:I was wondering if someone could check my math.  If, as has been said, this rocket stove can get by on 2 40 pound bags of pellets per day, and buying pellets in bulk usually come in a 1 ton quantity, then that would be 50 40 pound bags per ton (2000 pounds).  So that burn rate of 2 bags per day would last approximately 25 days.  Not quite one month.  The reason I ask, is that I usually get by on a little less than one cord of split wood in my hearthstone woodstove per month such that I can usually make it through the winter on approximately 3 cords of wood.  Now, I don't heat the upstairs, and the basement mainly gets heat soaking through the uninsulated floor, enough so that the pipes don't freeze, so I scale back to be able to get by on that amount.  I get a cord of hardwood tree trimmings from a tree service for around 180.00, so that gives me a grand total of 540.00 per year in heating costs.  I've don't think I've seen any pallets of pellets that go for less than 200.00, so to heat with a rate of 2 40 pound bags per day would run me right at 800.00 (approximately 100 days or 200 bags of pellets @ 200.00 per 50 bags).  I'm finding it hard to believe that 2 bags per day is a good burn rate, given my circumstances.  Do pellet stoves get a better rate than this rocket stove, or does 2 40 pound bags per day sound about right for any pellet burning stove?

inquiring minds probably could care less, but I want to know (c8.
Thanks,

Thekla McDaniels wrote:Speaking of pellets and the stoves that burn them, I have one, and it is my "solar assist" form of heat.  The building code people required some kind of assist, and so electric base board heat is also present, but never used.  I use less than one ton of pellets a year, so I guess my solar is working very well, but I don't keep the house very warm, so I don't "know" as in measured and documented.  

I have a pretty cold winter, conventional insulation (in 2x6 framing), and lots of glass.  The code people had input on the glass too.  Though it's designed to be shaded by eaves in the summer, I still have glass that reflects so much heat, that summer or winter, if the sunlight reflected from the windows hits your skin it is noticeably hot.  Even if I have sunlight on my skin, where the reflected light hits me, it is much hotter.  I am missing a lot of solar gain that the pellet stove has to make up for.

I don't know anyone who keeps their pellet stove burning continuously 24 hours a day, except the woman who sells them.  So, I wonder about the figures that say a person would burn a ton a month.

About the volume comparison to a cord of wood, the pellets are compressed, and I think there is a lot less airspace in the bags and stacks of bags, than in a stack of wood, a weight  comparison would give more useful information, average weight of a cord I guess.  And I guess pellets would compare to hardwood rather than soft.

I wonder too, about the calculation that an electric pellet stove uses $15.00 in electricity per month.  Again, I have no reference point, because I have solar panels in a grid tie system.  I think if the pellet stove were using that much electricity, then I would not run a net gain every year, I mean, I produce more electricity than I use, and as far as I can see, my biggest uses are the irrigation pump and the swamp cooler, but again, I never got one of those meters and went around the house measuring things.

I don't know if all this will be of use to anyone, but thought it was worth adding to the conversation.

Sky Huddleston wrote:

Pellets come in both hardwood and softwood variety

Thekla McDaniels wrote:

Sky Huddleston wrote:

Pellets come in both hardwood and softwood variety

but once they are pellets, a ton is a ton isn't it?  I thought I read that BTUs generated from wood are pretty constant by weight, whether from hard or soft wood, it's just that the soft woods take up more space, therefore a cord of soft wood is going to yield less heat/ fewer BTUs.  Or did I misunderstand?

Sky Huddleston wrote:

I don't know how large your house is, but running this heater on pellets constantly will likely heat you out of your house. Unless your house is over 2200 square feet, that is! Also, adding a flue damper will increase the burn time.By how much varies, but my estimates are anywhere from 14 to 20 hours.

Do note that a pallet of pellets is 4' X 4' X 4' which is half a card in terms of volume. Pellets are usually more than wood in terms of cost, people buy them for the convenience of a super long burn time.

You also must factor in that most pellet stoves use 15 to 30 dollars of electricity each month and their parts go out quite frequently and are very expensive to replace and time consuming to rebuild as electric pellet stoves are overcomplicated to say the least. The only wear part here is a 304 SS burn grate that one replaces yearly or so, and the part costs ten dollars. So this heater is already cheaper to operate just on the fact its non-electric alone. Thats not even factoring the cost of the replacement parts for conventional pellet stoves.

Pellets are an alternative to electric, fuel oil, and propane. In many area's of the country, you'll be hard pressed to beat the price of wood. Which is why this heater can also burn wood, too!

Michael Heath wrote:

Also, "adding a flue damper will increase the burn time".  Now I'm still in the studying and learning stage, but I kind of got the impression that you don't want anything slowing down the exhaust from a rocket heater (because it no longer sounds like a rocket?).  I assumed that was because you don't want backdraft or smoke ending up coming out of the feeder hole into the living space.  In my soapstone wood burner, I've found that I have to open the damper whenever I open the feed door or I can fill the house with smoke.  So a rocket heater CAN have a flue damper?  Does'nt that get a bit fiddly trying to keep it adjusted just right to lessen the burn rate and yet still allow enough of a throughput to keep the smoke from coming out the input?

Michael Heath wrote:

Don't get me wrong, we just went through 3 hours of no electric after a storm (longest in 5 years, so I guess we were due), so I understand the need for not being tied to the grid.  In fact, that was one of the considerations behind our choosing a soapstone stove, the fact that it could keep the pipes from freezing without the need for electricity.  But just because I understand it, doesn't mean I wouldn't want the convenience that comes with electricity and pellets.

Michael Heath wrote:

It seems then that you offer a good middle ground.  Pellets, so convenience over wood and comparable burn rates, but no electricity so less convenience than a more automated system.  Have you given any thought to maybe running on very low wattage/amperage?  Something that might be sustainable by a deepcycle battery?  The three uses for electricity (that I see) are pellet delivery, thermostatic control and starting a burn in a cold stove.  You have already solved the pellet delivery, a low amperage solution could also take care of the thermostatic control.  The only problem I see with a low watt electric system is when it needs to start a cold stove.  That low of an amperage would not operate a heater to start the pellets.  Or could it?  I suppose it could, but that would take a lot of juice from the battery so you couldn't do it very often.

Marla Kacey wrote:Hello, Sky!!

Amazing product!!  At 60, and loosing vitality on a daily basis, building my own rocket stove seems rather unlikely.

One simple question:  if I pay for one of your stoves today, how soon can I expect delivery to a small town near Laramie WY?

And, after reading this ENTIRE thread, I hope you haven't already answered and I just missed it.  Hate feeling dumb.

Thank you so much!

Sky Huddleston wrote:
^Our rocket heater can also burn wood, too. So you are not tied to pellets. You can burn free fuel in the form of sticks and waste during the day, and pellets when you are gone and for overnight. This extreme versatility is something no other commercial pellet or wood stove can offer.

Scott Saxon wrote:

Sky Huddleston wrote:
^Our rocket heater can also burn wood, too. So you are not tied to pellets. You can burn free fuel in the form of sticks and waste during the day, and pellets when you are gone and for overnight. This extreme versatility is something no other commercial pellet or wood stove can offer.

I read the entire thread (whew) and have one question.  Sky, you said it would burn waste, and the video of the guy "testing" showed he fed in coal and even a duraflame log down the regular feed tube.  I am thinking your stove will burn darn near anything, including wood chips.  Evidently most pellet stoves will not burn chips, due to the auger feeds, but it looks like anything you put into the hopper will drop down into the burn chamber and get consumed.  In our situation, for at least this one winter, which is fast approaching, where we will be living in two RVs inside an 1800 sf presently uninsulated pole barn in Minnesota, where temps can get to sub zero I'm told, we will likely be burning 24-7.  So instead of buying pellets for $dollar$, couldn't one get a chipper and run some sticks through the chipper and then feed the chips into the hopper? This property has maybe 40 acres of wooded land that has been neglected for probably 20 years.  Lots of usable wood in all sizes and states of decomposition.

We'll also be setting up a simple inefficient cast iron stove that we can throw logs in during the day, but it won't carry us through the night.  We figure if we can keep the barn to 50 degrees or so, the propane heaters in the RVs can do the rest.  This is a temporary fix for this winter only.

I am collecting bunch of more efficient ideas and plans, and will eventually be insulating the two pole barns - setting up my machine shop - rebuilding the 1860 something farmhouse - building more rocket stoves and waste oil heaters - and playing with other heating sources, but I'm told the first freeze could arrive as soon as September, (a few weeks away) so for this one winter, we are primarily concerned with, well, actually surviving our first winter here by heating this one barn.  Fortunately we are still young and strong (71 and 73).  

Hopefully pretty soon I will set up the sawmill I made and will get a lot of sawdust from that.  Will be looking into making some sort of machine to reclaim that and press it into logs too.  But that won't happen until we are set up in the barn.  Priority one, don't freeze.

Sorry, I wandered off a bit, but wanted to give an idea of our situation.  And yes, according to what I've gathered from this forum, we could just buy enough pellets to burn 24-7 for about $250 a month, which is not unreasonable.  We could do that, but why not use what is free and at hand?

The problem with wood chips is the inconsistent sizing and bridging issues. The chips have to be extremely small, consistently sized, and even then its probably not going to be 100% reliable. We haven't tried it with wood chips so we dont know for sure if it will work. Every chipper produces slightly different size and shapes of wood chips.

Scott Saxon wrote:

The problem with wood chips is the inconsistent sizing and bridging issues. The chips have to be extremely small, consistently sized, and even then its probably not going to be 100% reliable. We haven't tried it with wood chips so we dont know for sure if it will work. Every chipper produces slightly different size and shapes of wood chips.

I think I'll try it.  Maybe screening them to get some consistency in size.  Of course, to try it, I'll need to order one.  I'll do that now.  

Scott Saxon wrote:

The problem with wood chips is the inconsistent sizing and bridging issues. The chips have to be extremely small, consistently sized, and even then its probably not going to be 100% reliable. We haven't tried it with wood chips so we dont know for sure if it will work. Every chipper produces slightly different size and shapes of wood chips.

I think I'll try it.  Maybe screening them to get some consistency in size.  Of course, to try it, I'll need to order one of your heaters.  I'll do that now.  

Rob Yost wrote:Hi Sky, I am very interested in installing one of your stoves. A couple of questions, do you foresee any problems burning mostly cedar?  I have access to lots of fallen, dried cedar, I am mostly worried about sparks coming out the feed tube and creosote build up.

Second, have you or anyone else played around with phase change materials (PCM) as an alternative to thermal mass?  My thoughts are to build a large steel pot to put on top of the heat riser with PCM materials inside. See http://www.pcmproducts.net/High_Temperature_Salt_PCMs.htm for details. My goal would be to light it twice a day and keep the house comfortable.

Lastly, have you shipped any systems to Canada, and if so, what are the approximate shipping costs?

Thanks for your dedication to clean and sustainable heating!