rocket mass floor heater -- finally completed and it works!

Our big concern was to heat the yurt.  The heating of water was kind of an afterthought, as a way to further use the energy we're burning to heat the yurt. 

I've had the last two winters to get first hand experience with the "heating a pot" method for bathing.  Hot running water systems of most types may not be super efficient at getting water hot, but are a HELL of a lot more convenient.  That's probably why they're so popular. 

I'm not making any accusations, but I can't help but wonder if people suggesting these things have lived for a significant period of time without hot running water.  I lived for awhile without running water PERIOD, and it really changed how much I appreciate a tube that gets water from one place to another without me needing to physically carry it.  It saves time and calories. 

I like to take advantage of certain technologies, so that I can have the energy to do all the other stuff I have to do that maybe isn't so technologically advanced.  Like - milk a cow, chop wood, and grind flour, all by hand. 

I LOVE to turn a knob and see hot water flowing in to the bath tub.  It seriously makes me giggle every time.  If it takes a little more wood to get there, so what?  We've got lots of it and we're burning it cleanly. 

I like Erica's idea of a directly-heated tank with a tube coming out of it.  Will tuck that idea away for future designs.  Frankly, I'm all for avoiding carefully lifting and pouring large vessels of hot water (I still do it everyday to wash the dishes).  In my opinion and experience it's one of those things that "sounds simple" and is a grind if you do it every day.  (it's not annoying to do the dishes, but I can get those done with a gallon)

I need two gallons of water to wash my hair.  And one more to wash the rest of me.  I only do the hair thing every seven to ten days, but again, I LIKE hot running water especially for that.  I do not NEED it, but I really LIKE it.  I feel that the bath tub in the yurt, with the water system we made, has improved my quality of life. 

Thank you both for the corrosion explanations.  It's very interesting, and I feel like I mostly understand it.  I'm not that worried about it, as our yurt doesn't leak, if it did we'd fix it, and we generally take a not-so-steamy bathe a few times a week, a few months out of the year.  In general this climate is not as humid as are areas closer to the coast and further north, even in the winter. 

Cleaning clay off steel tools is a very good idea in any climate.  A lot of my clay tools are wood, but I guess the clay would help them rot more quickly if I left it on there.

The yurt is very leaky as far as air goes, and this gives it outstanding air circulation.  It's also warm in there practically all the time.  I haven't put a humidity sensor in there yet but I'd guess it's pretty dang low. 

Things were very humid in there when the cob was drying out, but that's before we had the copper pipes in place. 

For the record, that 60 ft roll of copper pipe cost us a little more than $70.  Maybe the home despot employee made an error ringing it up, but $5 a foot sounds really expensive. 

No one answered my question about putting a thin layer of cob between the barrel and the pipes.  After it dried out it seems like it would be a very stable barrier between the two metals?  Am I missing something?  I don't wanna go buy paint or grease.  I want to use what we've got. 

Frankly, I'm all for avoiding carefully lifting and pouring large vessels of hot water (I still do it everyday to wash the dishes).  In my opinion and experience it's one of those things that "sounds simple" and is a grind if you do it every day.  (it's not annoying to do the dishes, but I can get those done with a gallon)

What you wrote reminded me of a show I saw on PBS years ago, back in 2002.  The producers took three families and brought them to Montana.  The families had to live life just as the pioneers lived -- cutting the wood with axe and saw, planting using a mule and a plow, etc.  One thing that the families and the producers all noticed was how long it took to heat water to do dishes and wash clothes.  It took everyone by surprise, including the historians.  As one historian monitoring the project said, "People would find these homesteads that had been abandoned, and they always found the dishes had just been left where they were last used, instead of being washed!"

Muzhik wrote:
What you wrote reminded me of a show I saw on PBS years ago, back in 2002.  The producers took three families and brought them to Montana.  The families had to live life just as the pioneers lived -- cutting the wood with axe and saw, planting using a mule and a plow, etc.  One thing that the families and the producers all noticed was how long it took to heat water to do dishes and wash clothes.  It took everyone by surprise, including the historians.  As one historian monitoring the project said, "People would find these homesteads that had been abandoned, and they always found the dishes had just been left where they were last used, instead of being washed!"

LOL that's a new take on the "eerie scene of abandoned homestead."

Ernie suggests two additional factors: 1) Dishes are heavy. 
(Imagining that final scene as the dysfunctional pioneer household surrenders their dreams, factor in the well-worn rehearsal of disagreement over the dead weight of grandmother's bone china.  There is a place on the Oregon coast called China Creek 'cause somebody's heirlooms landed there when the wagon got stuck once too often.)

2) Ernie always figured people set the table for security while on a hunting trip, etc - "don't get caught red-handed, we'll be right back," and then plans change or accidents happen, and they never do come back.

I'm all for hot running water.  Appreciate it, every time I use it, and I can totally see why a system you built yourself after years of privation would make you giddy. 

It's just that so many people underestimate the complexity or risks involved. 

You've managed to create a relatively safe, relatively effective system on the first try.  But I don't think most people would do as well. The general level of quality on your build suggests that you have good instincts, pay attention, and do your homework - and that when something seems iffy, you fix it. 

So sorry, you're not 'normal' in this case.

I've camped (for 1-3 week periods) where home-made water heaters and solar showers were available.  After inspecting them and hearing how they work, or fail to work (scalding and freezing, lukewarm brown scum, loading and stoking and waiting), I found other options.  Damp washcloth, go swimming, pail and pitcher, or go into town for a shower.  This summer I even cut my hair so I wouldn't have to worry about washing it at camp. 

I could go a long time without hot running water, but I do enjoy it in winter. 
If I was building a long-term living situation, I'd try
1) Apply Ernie (or someone with similar high-temp water/steam experience)
2) Simple, like the pot-with-a-tap;
3) Commercial device with compact fuel source; or
4) Something like you have, that sacrifices speed for safety; only with cheaper parts.
5) Direct-solar if I could figure out how to store the water.

I would continue bathing out of a bucket before I'd use a system that sacrifices safety for speed and heat.

Apologies.  When you wrote,

1) Apply Ernie (or someone with similar high-temp water/steam experience)

I had this sudden image of Ernie being plastered intact into the wall, so you could pull him out as needed, or perhaps attached to the end of a pole.  Very disturbing.

With all this talk about safety, I thought I'd post a link to the Mythbusters episode where they tested out the myth of a water heater rocket.  The myth was that a water heater exploded and launched itself straight up, going from the basement through three floors and out the attic roof.  The entire video is about 10 minutes. 

[youtube]http://www.youtube.com/watch?v=pu3FwgIHsQA[/youtube]
[youtube]http://www.youtube.com/watch?v=pu3FwgIHsQA[/youtube]

If you're a guy, you'll recognize the true beauty and art that resulted, at about 4:29 and again in high-speed slow motion at 5:30.  You'll also want to go check to make sure all the safety features on your own water heater are working properly.  WARNING: the audio on this is really low -- I had to crank everything up on my system to hear it properly.  Wouldn't be an issue, except when my "new mail" alert sounded, it caused my sleeping cat in the other room to  jump.

Marina, I think the "thin layer of cob between the barrel and the pipes" should do the trick.  Cob isn't much of an insulator but it keeps heat well, meaning it might help keep the water in the pipes warm as the fire dies down.

You may be interested in checking out Green Science Power's channel on YouTube:

http://www.youtube.com/user/GREENPOWERSCIENCE#p/u/5/St-0HWKAY4k

Somewhere in there they have two videos about their project to give them solar heated water by putting dark-colored plastic tubing on the rood of their carport.  Perhaps you could do something the same on top of your yurt.

(Yurt.  Sorry.  Whenever I say that word I think of Dr. Seuss...)

One thing that the families and the producers all noticed was how long it took to heat water to do dishes and wash clothes.  It took everyone by surprise, including the historians.

Yup, I used to be one of those that liked to do the dishes immediately after every meal.  Now we do them once or twice a day, depending on the number of people here and the volume of stuff to be washed.  If you have a large container of water on the stove the whole time you're cooking, the water is hot by the end of the meal and there's no waiting.  If you wait til you need hot water to begin heating some up, it takes a really long time. 

Using wood heat efficiently is all about multi-tasking.  In the summer, I cook breakfast and lunch at the same time so that we don't have to have a fire in the middle of the day.  I do dishes after breakfast and and after dinner, when we have hot water as a result of cooking a meal.  In the summer, we can always go borrow hot water from our solar system at the end of the day as well.

We have a solar hot water heating system that we use for showering in the summer.  It works great - you can have a warm shower by lunch time and at the end of the day we have 65 gallons of 180 degree water, enough for four or five fairly short showers, or two-three really silly long showers. 

It consistently freezes here this time of year, we have to drain the whole solar system so the pipes don't break.  Also, solar hot water heaters don't work at all if the sun isn't directly shining.  The winter season here is mostly cloudy, the days that we do get full sun, it isn't out for enough hours to heat up water enough for showering.  So, in the winter, we have to burn something to heat water. 

Since we're burning something to heat our interior spaces, it makes sense for the same system to also heat water.  Multiple functions for the same element, I believe that's called, in uber permie language. 

BY THE WAY, the video of the rockety water heaters gives me a new found respect for the amount of damage that is possible with faulty water heating set ups.  Ours is not in that category, as Erica so nicely explained. 

I have an "Ernie" but his name is Robert, and I feel really lucky that he lives here, loves me, and helps all of our projects be structurally safe and physically possible.  He worked in the commercial construction world for two decades, and has been homesteading practically his whole life.  When we get around to doing the water heating systems of our "real house" we will most likely hire a professional to help us figure out the more complex systems that we're envisioning. 

We were talking about another barrel welded onto the top of the rockety burn chamber outer barrel.  It could even just have a heavy lid as a steam release valve?  There would be very little pressure, but it seems it could heat water that could drain into a bathtub.  I think it would be a manual refill too.  It would also add a huge thermal mass to the whole system.

I uploaded some more photos of the firebox, including the whole fire starting process.  There was hardly any smoke at all.  It would probably be most smokey for the first fire of the winter season. 

Erica, I just watched Paul's video of you explaining the rocket floor heater.  The damper that short-circuits the exhaust tubes is brilliant!  We thought about installing dampers at the beginnings of three of our exhaust tubes, but the test fires just kept showing us that they weren't necessary in our system (exhaust comes out all four tubes pretty evenly), and would have made the cob area inside even bigger, so we decided to leave them out. 

I also noticed your hair cut!  I had always admired that thick braid on the side of your neck, but I understand the ease of short hair.  Hilariously, I started growing my hair out right before I moved to a situation with no indoor plumbing....not really on purpose, it just happened.  It hasn't been that hard to care for, since I don't need to wash my scalp any more frequently than I did with short hair.  (I had a pixie cut for a decade.)  Took til it was below my shoulders to break down and buy a comb. 

I really like the videos on rocketmass heaters... I had one question  It seems that you can't put much wood in at once  and no big pieces  Do you have to tend the fire more often that a regular woodstove and do you have to cut the wood int smaller pieces?  I really want to build a bench.... thanks  Sam

Your going for a different burn Samiam, fast and hot, vs slow and low like you get with real big chunks of wood.  The burn is so much cleaner than what your getting with large pieces of wood, much more bang for your buck or heat for your wood-size.  It's a totally different process to heating with wood, not just a different stove design 

You can read more about it from this -
http://www.google.com/search?client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&channel=s&hl=en&source=hp&q=why+use+small+wood+in+a+rocket+mass+stove&btnG=Google+Search

Marina,

I sent you an email, but I'm not sure if the email address I have for you is a good one. 

I want to modify your post to put some of your pictures in it and then tell others about this thread and what you have accomplished - any objection?

Obviously I need to check that email more often than I do, Paul.    I'd be delighted to see pictures in here.  Promote in what way, is my only question? 

I've found it can be difficult to explain RMHs to people who only know about conventional stoves.  For the barrels, we bought the rolled metal tubing from a machine/metal shop and Robert's Uncle B welded the seams together.  He listened patiently as we explained the whole thing with pictures and words, and then kind of very politely told us it wasn't going to work: "Well I've built a lot of wood stoves in my day.....and I've never seen anything like this....." 

We were happy to finally report that it DOES work last we were at Uncle B's house, and we're hoping he and his wife come up for dinner in the yurt one of these evenings.  Seeing/feeling is believing.  They work really really well, when put together properly. 

I sewed all day in the yurt yesterday, and it was twenty degrees warmer in there than outside with no fire since the late afternoon the day before (60s in the yurt, 40s outside).  It's so cool to have a warm place with no fire to worry about at all.  And to be barefoot on a not-seriously-warm but not-at-all-cold floor is really awesome too. 

We're discussing/dreaming a ten inch system for the house......

I got your email giving me the green light.  And I got some pictures in.   I just think you have something really cool and I wanna point it out to a lot of people. 

Now posted out at reddit.  (edit:  and where they appear to hate it - it has been downvoted enough to be taken down)

I've never been to that site before today.  So the RMH was down voted.......And yet the chess set made out of bolts got 50+ comments.  Figures.  Why would you need to do anything other than turn a nob a few degrees to regulate heat in an interior living space, anyway? 

Reddit is an awesome site.  I am still trying to understand it.  I put this in a couple of other subreddits and it is doing much better. 

I have a guy that is like my own personal cyber stalker giving me grief, but other than that there have been some nice comments.  I thought this one was really funny:  "it's like amish porn."

Here is  a comment you might like:  "Well, that's sorta too green for me. But at least she's hot."

Hello from Reddit!  Your rocket mass heater made the front page of r/frugal, which I subscribe to.  I think it's great to see creative uses of resources, and thank you for taking the time to document your build!

Don't mind the early downvotes; because so many sites get promoted from reddit upvoting, there are users and website owners who actively try to game the system by downvoting everything except their own submissions.  Quality material still seems to rise to the top despite early downvotes though.

paul wheaton wrote:
"Well, that's sorta too green for me. But at least she's hot."

Gosh, I'm glad someone finally said it, I've been biting my tongue for a week.....

bookishboy wrote:
Hello from Reddit!  Your rocket mass heater made the front page of r/frugal, which I subscribe to.  I think it's great to see creative uses of resources, and thank you for taking the time to document your build!

Don't mind the early downvotes; because so many sites get promoted from reddit upvoting, there are users and website owners who actively try to game the system by downvoting everything except their own submissions.  Quality material still seems to rise to the top despite early downvotes though.

Yowza!  It hit the top of page 1 with 90 upvotes!  And you guys utterly crushed my cyber stalker - I have never seen anybody get that many downvotes.  Sweet!

What you have to say about the early downvotes makes a lot of stuff now make sense.  It seems every day I learn a little more about the wackiness at reddit.

swoon

Uhmmm.....wow.  Cool!  I sincerely hope the stove is getting most of the attention.  Thanks for the self esteem boost!  And thanks for showing off the RMH Paul!  Not something I would have thought to do.  I'm not quite that shameless in my self promotion. 

Also, it was a group effort.  The slapping on and shaping of the cob is the end result of a whole process.  Couldn't have done it without interns sifting quite literally tons of sand, and Robert taking care of the technicalities.  And, I was merely mortar girl when we were building the brick structure, he made that 67" tall chimney stack with his own two hands (and no prior experience!). 

Marina, Great thread!
you guys did a beautiful job on this RMH/Yurt, really enjoyed the photo journal. and what an awesome property

when you mentioned the japanese bath it made me recall a show i once saw on "green homes"
the homeowner designed a jacuzzi/bath tub into the floor of his bathroom beneath the shower, i thought it was ingenious!. wonder if sinking your tub into the floor would be an option for you,to help insulate it aroud the sides,and also give extra living space above(cover made of bamboo flooring,flush to floor )  just an idea
this is almost what i mean.lil on the ritzier side though.

Thanks, tribal wind!  Every time I step into the warm yurt I know it was worth the effort. 

Cool photo, that is ritzy but I get the idea.  We've talked about making a cover for the tub so it could be a table, but in reality it's too far into a corner to be useful like that, and we just fill it with beanbags when we want the middle floor space clear.  It's not in the way so much. 

Plus, being right next to the stove, the cast iron of the tub stays warm.  I've used cast iron tubs in some cold bathrooms on the east coast, and you have to put reaaaalllly hot water into it to get a nice bath temp. 

It's an interesting idea, but I'd rather not cut a big hole in the floor (in case that tub gets to live somewhere else someday), and the part of the floor it's resting on isn't insulated as well.  The gravel box is just the middle part of the room, there are four smaller areas (close to the walls and mostly covered in shelving) that just have the foam insulation right under the floor.  They feel waaaaaay colder than the part of the floor above the heated gravel.  It's amazing, the difference. 

But in our "real" house (which is more of a "dream" house right now) we're totally talking about sunken tubs.  I think they look cool, and it's nice to not have to climb over the side.  And old cast iron tubs without feet are cheaper and more common than the ones with all four feet.  (I spray painted (I KNOW I KNOW kill me for my emissions) that yurt tub to make the outside look nice, the inside's a bit of a mess)

I like the idea of a slatted floor in a shower that lifts up to reveal a tub underneath, the shower water just drains in the same drain as the tub.  Ok, but I just had the thought that all the residue from the showering process is going to coat the tub, and you might have to clean the tub every time before you filled it......

We were just given an old redwood water tank, in pieces but with all the straps and stuff.  I'd love to have it half sunk in the floor, at least, and you could insulate it really well under there.  I like the japanese style of bathing where you shower and then there's a large tub of hot water that everyone shares, after they're clean. 

Your talk about "cast iron tub" put my neurons in firing position.  This is NOT something I would do without someone being in the yurt at all times.  It's a variation on the "redneck hot tub" idea.  Try making some "hobo stoves", where you stuff a tuna can with corrugated cardboard, then fill it with melted wax (old candles?).  Take two or three of those, put them on the floor under the tub, and light them.  Do this BEFORE you put ANY water in the tub. 

I know from experience that one of these tuna can heaters, packed tight with cardboard before adding the wax, will burn for at least two hours, maybe three, before you have to extinguish the flame and add more wax.  I'm thinking by the time you extinguish the flame, these heaters will warm up the tub considerably.  When you add the water, it will cool down the bottom of the tub (so you won't burn your butt when you sit down) and will add that heat to the water.  If you feel adventurous, you could try leaving one heater lit while you're bathing, turning the tub into a giant chafing dish and keeping you toasty warm while you soak.

I have no experience with cob, but do you suppose a coat of whitewash (hydrated lime) would do any harm viz. the barrel bonding to the cob?

If not, it would be enough of an extra assurance that I would recommend trying it.

Marina I really like the set up you have. Thank you for posting the photos, and labeling them was a great touch.  I am new to all this and it was very helpful.

Thank you Jim Bunton

Anybody here thought of making the heat riser throat a water jacket, instead of wrapping the outside of the barrel?

Hello I see that the posts on this topic are old but I thought to try anyway.
I had recently purchased and put up a yurt 20ft, anyway I saw your post on heating and was blown away, I am not sure but it appears you built the yurt around your rocket mass heater? I mean you built the heater and then assembled the yurt on top, am I correct? I was wondering if you had any pics or drawings of what you actually did? I am wondering because we plan on moving the yurt to a different location once I clear some more woods, and I would love to incorporate the RMH for heating if possible- also what did you but in between the yurt floor and the Heater? I would think it also helps keep it cool in the summer since adobe/cobb tends to keep cool like stone, llok forward to hearing from anyone on this subject.
Thanks

semi-offtopic: the original poster is 'anonymous'. Is that someone with a deleted account?

pete samson wrote:semi-offtopic: the original poster is 'anonymous'. Is that someone with a deleted account?

No, it was actually an anonymous user. The old forum software, as it was configured a long time ago, allowed for anonymous users. That configuration option was turned off quite some time ago in the old forum software, and is not allowed in the new forum software.

Pictures of the building proces

Dave trusewicz wrote: I was wondering if you had any pics or drawings of what you actually did?

I had the same question and found al link somewhere in the text above to some pictures. It's easy to overlook, so I present it here for everybody that happens to stumble on this page like me and wonders how this beautiful floor heater was made.

Hi All : I'm spreading the net wide ! I created the forum thread 'Rocket stoves in greenhouses' - - -for self-identified members interested in rocket stoves in greenhouses, most of them want to have their thermal mass below ground level and some are interested in outside feed boxes like here !, This way 'our' group can have their own forum thread, check in , check often, Allen L.

Anonymous : just wanted to check in with you, a question has been raised by a member regarding the use of Multiple Exhaust Channels, yours is the only build of this type we have located here at the ' Permies Forums '.

Our area of concern relates to the use of dampers to close off exhaust pipes, horizontal or vertical. This would be done to direct the exhaust gases to different thermal masses in different locations, certainly a novel idea !

I am checking in with you to ask if you had ether full dampers to close off any of your exhaust pipes, or part dampers to balance the flow between any of your pipes ! Thank you for your time , Pyro-maticly yours, - Allen L.

(I know this thread is old, but hope springs eternal...)

To the couple who did the floor heating system for the yurt, are you still using it, and have you experienced any issues with condensation collecting in your exhaust pipes?

I'm considering similar, but the engineer in me keeps warning that this is essentially a condensing heating system, and as such, is likely to collect moisture if it isn't given a place to drain away.

I was wondering the same thing; any problems since the build?

i am about to start on a similar system for my yurt so another bump. anyone know if the OP is still around? i know the thread is 4 years old but it is is such a good design i am interested in finding out if it is still working.

Allen Jackson wrote:(I know this thread is old, but hope springs eternal...)

To the couple who did the floor heating system for the yurt, are you still using it, and have you experienced any issues with condensation collecting in your exhaust pipes?

I'm considering similar, but the engineer in me keeps warning that this is essentially a condensing heating system, and as such, is likely to collect moisture if it isn't given a place to drain away.

You have to keep in mind a couple things, this is a system that is open on both ends and has a couple thousand pounds of heated mass in the middle. water doesn't collect in warm places with airflow in my experience.

So how much cost to build this rocket mass floor heater?

bob golding wrote:i am about to start on a similar system for my yurt so another bump. anyone know if the OP is still around? i know the thread is 4 years old but it is is such a good design i am interested in finding out if it is still working.

I think this is the lady that Paul has referred to in recent podcasts that was driven away from other people's hate. It is a shame, because they were doing lots of cool new interesting things.

Some people have really stupid ideas that need to be stopped (like risers that don't rise) but this was cool and different in a non-dangerous way.

Ecco Stove : Fast answer, hundreds of dollars, ( added onto the cost/value of the building ). Please note that an in floor Rocket Mass Heater RMH, With multiple
Exhaust Channels and extended Burn tunnel is an advanced project with a physics related requirement for the Heat Riser's Length/Height to be at least 2 Xs the
length of the burn tunnel, this will make the Top of your heat riser and barrel vey tall and unhandy to use, exactly what we do not want with any RMH !

A more conventionally built RMH (100,000 + World Wide ) Might cost a couple of hundred dollars,less if you are a great scrounger, and be a simpler build.

Two recommendations :

Goto Rocketstoves.com, for a PDF Downloaded copy of the brand New 3rd edition of Rocket Mass Heaters. there is a 25% Discount code for the
Download by typing in ''Fakeboob"

Read the book carefully, and practice all your 1st builds out of doors before you move it inside. Any questions, you can come back here for help, with nearly
25,000 Fellow Members, world wide you should be able to come here 24/7, and find help on this and 1000s of other topics ! Big AL

Late note : When you come back Start a New topic Hear in The Rocket stoves section, we do not want to be accused of Highjacking a thread ! Big AL