All brick rocket stove greenhouse heater

Will a 100% brick version work to heat a greenhouse? Instead of using a metal drum. Will the bricks or mortar crack? I won't need quick heat so I made the "riser" part also out of brick. I'll build the exhaust into the floor for the rest of the thermal mass.

James W. : Welcome to PERMIES, and a big welcome to the Rocket Stoves Forum and Threads ! Please go to ,Rocketstoves.com'and download your PDF Copy
$15.ooU.S., of Ianto Evans, Great book ''Rocket Mass Heaters'', There is no other book with more 'rocket stove information' in any language !
( -and I don't make a dime ! )

I read your question carefully, You are starting off thinking 'out of the box', which is a good thing, thats where all our improvements come from ! I am used to
thinking of the barrel as though it was a type of short cut , and not a problem ! Unfortunately, we need the barrel!

After we have achieved a good clean burn at the bottom of the Feed Tube,with the flames from our initial burn flowing horizontally through the Burn Tunnel,
we have to increase the turbulence and oxygen mixing for the start of our second high efficiency burn. Here we expect Temperatures at the top of the Heat
Riser to climb upwards from 1200F!

Here we get to one of the magical parts of the Rocket. The heat energy shed as the hot gases Flow from the Heat Riser and past the barrel cause the gases to
cool and fall, This creates the pump that drives the rest of the hot gases through the Horizontal thermal bench ! A Brick Barrel would be called a brick 'bell', and
is very useful in other locations, but not here! Here we need the barrel to radiate off enough heat to create our "Heat Pump''. ( My Word Choice !)

There are bricks and then there are other types of bricks, some do work better than others, here again we get to use what we have, and what we can get !
If we use mortar with portland cement We are introducing a material with different expansion characteristics than the rest of the build, this will definitely cause
cracks !

As you read further through the Forums you will find that there are many plans to take advantage of the heat given off of the barrel, but a very good reason
would be to have some way to add additional heat as a new cold front comes through! There is much development work in using water as the Thermal Mass,
here we need to proceed carefully, Working safely to reduce the Risk of High Temperature Rocket stove gases making contact with any amount of confined
water to 'Flash to steam' creating a Boom/Squish event we would wish to avoid !

Keep thinking outside the box ! For the good of the Craft! Be safe, keep warm! PYROmagically Big AL

Well, I have read that the barrel can be all covered with the clay mix, so as to limit the strong radiation and the convection that also occurs there!
So gases would not go colder so quick...
and you say this is absolutely necessary?

I have read that you have to chose your rocket use, between more heat for the bench, or more heat on the barrel, for cooking.
If you want more heat for the bench, then you also loose less at the barrel level.
So please, what is the necessary temp drop?

I also would like to limit the heat loss at the heat riser/barrel level...
And thus I wanted to build with stones, around a tuff (for insulation) core unit.
Well, you can have a look at my project, the one "for warm country".

You tube with all bricks:
a brick floor heating, even contradicting that the burn tunnel should be short:
http://www.youtube.com/watch?v=uyO2JtkwOuk

Refractory masonry here:
http://www.youtube.com/watch?v=-jzKKIHhTU0

Only bricks here (no way to understand!) http://www.youtube.com/watch?v=NaZtGVhSmNo

Another one with only bricks
(and an iron top for cooking)
http://www.youtube.com/watch?v=xMrgxaujfg4
It is even all square, and the flue exit is only an aluminium tube in the wall!
The pics show that it has been working, they do not only show the building.

James W., Xisca N., :O.K., I will stick to what i have already posted here, - though I wish now that I had picked my words more carefully !

As I have already stated, The Science of Rocket Stoves, lets us use what we have on hand, adapting as we go ! The Book "Rocket Mass Heaters"
is set up to give us a build that will work for nearly everyone who can follow directions ! I would also view all contributions from 'YouTube' with
a grain of salt. Find a good well documented build, contact the builder to check that you can ask him Questions, ( or follow the build in the book )!
Just because it worked for several seconds in a video, does not mean it is still in use today !

In order, the 1st video is not really a rocket stove at all, it burned horizontally less than 5' and only after the chimney was warmed 1st !

In order, the 2nd video was not a Rocket Stove,Moved hot exhaust gases about 12'=13', Needs the fan to cool down the brick stack to allow the
gas flow to happen, and needs the chimney to be heated 1st !

In order, the 3rd video is definitely a masonry stove, and uses a diverter to allow warming of the chimney before Transferring the exhaust gas
stream to the piping!

In order, the 4th video Shows a masonry heater, with a metal pipe chimney, unknown builder, unknown location, apparently in a basement
location,this would be an advanced build, and 'mimmutsi' shows several builds leading up to this one ! While there are many hybrids of masonry
stoves and Rocket stoves, and I have helped on several Rocket Stove builds, which all worked, I would never consider attempting a Masonry
Stove on my own, without someone to refer to, and a set of plans to follow ! Our most expensive build, where one small mistake can cause
catastrophic and expensive total failure !

James W., The most important times as far as correctly sizing your Rocket Stove/Greenhouse is warming the space to allow for the start of the
Heating season ! During the times that create the biggest demand on your heating unit, you also need to consider the need to store your wood for
your Rocket Stove at a near but separate location Due to the need to have very dry, small wood and, the high moisture levels within most green-
houses, a separate co-located Wood supply and Rocket stove will protect your dry wood and prevent the cooling down of your greenhouse by the
simple act of carrying in the fire wood to heat the greenhouse !, Again there are many things to consider about using any wood stove for heating
in a greenhouse, and local conditions will require local changes, A fan could be used to move air from the wood drying area to the greenhouse as
part of required air exchanges to cut down on mold and blight problems!

As always I am open to all questions and will do my best not to lead you wrong !

For the Craft! Be safe, keep warm, PYRO Logical Big AL !

Xisca,and James : You both might like to look at the 'Homemade Mass Heater' Thread in the Wood stoves forum, as built, it is close to a good masonry stove
that a careful D.I.Y. Builder could follow, but still comes with problems getting the heat from the heater to your thermal mass ! Big Al !

Thanks Allen

As we can see the building inside, the 4th video rocket really looks like having all the characteristics of a RMH. The family photos afterwards show that it is working in the long run.

Some problems come when one cannot do the EXACT plan in the book. All questions in this forum show that we cannot find all answers in the book! I really wish the most experienced people would gather for re-writing something...

If the metal is needed for cooling down the hot air, then why have I also read in the forum that it is possible to cover it with clay, so that more heat can go into the mass?

Has building with bricks instead of a barrel really been tried or not?

I have some more to say for getting ahead through issues, but I will put them in my thread so that solutions can stay here for what the title says: a greenhouse heater.

So here: https://permies.com/t/24439/rocket-stoves/rocket-adapted-warm-place#195362

allen lumley wrote:Xisca,and James : You both might like to look at the 'Homemade Mass Heater' Thread in the Wood stoves forum, as built, it is close to a good masonry stove
that a careful D.I.Y. Builder could follow, but still comes with problems getting the heat from the heater to your thermal mass ! Big Al !

I did go... I just have no room for this
-> that is why I want to heat the floor. Only a rocket stove can send the heat down there!

I want to make something cheap and local, and want to avoid buying a door, and also avoid industrial insulation.
But I definitely want this slow radiation, as I have to heat and be able to keep some fresh air coming in for drying in winter.
And I realized that the oil drum would give too much convexion.

Wow! Thanks everybody for all the comments and help! These projects look like good fun! I very much appreciate being able to bounce ideas off you all.

I downloaded the book and have read the body of it – thanks! I am reading through it again a second time so it sinks in a bit better and I can converse more intelligently. There was indeed a place that talked about covering up part or all of the drum with cob so more heat would go to the thermal mass. But I do get the physics - that pressure increases in the burn tunnel as gasses heat up and expand and decreases downstream as that heat is lost on the drum’s surface. I understand that this creates the pump which seems to be an important part of the rocket.

I’m not sure how much a temp drop is needed and didn’t really understand the ram pump link. But I’m already thinking more intelligently about this! Woot! I’m also not sure how other types of fires differ (masonry vs rocket).

I’ll use some sort of clay or fire clay for the mortar.

Allen, you bring up something I have been thinking about – correctly sizing the heater to the greenhouse. I’ll be heating one of those 10 x 12 Harbor Freight greenhouses. They are “double walled” but my last one (sold with the house) was not sealed up very well. Unlike most people, I’m not trying to get a jump on spring planting. I live in S. Fl and want to be able to keep the temps above say 50F so I can grow some sensitive tropical plants to sell at local markets. And I’d like to use wood and other natural fuels (yard waste, we have an acre) if possible. One challenge is how big to make the heater. I really don’t want a huge thing that takes up a lot of room in the greenhouse. Something with a 55 gal drum is way to big. On the other hand, something to small may not scale well – it may not be insulated enough to reach the high temps needed for a full burn. I can use the floor as my thermal mass and save/double duty space there. I may be able to use the heater as a working surface when it isn’t in use. I certainly can easily find “urbanite” for thermal mass.

The new plan is to follow the books design but make something smaller that doesn’t have a huge footprint. How small?

Has anyone made a small one with a #10 can as the drum? Can you make a smaller rocket heater out of clay? Or will it heating up differentially cause problems? What it was made in parts that fit together?

The greenhouse will be very humid, will likely have fish tanks (thermal mass but will have fish in them so they can’t get to hot) and will likely also have a mist system. I know I can’t store the wood in there but had not given that aspect much thought. Since I’m designing the whole thing, it is good that you brought that up! Maybe I can build something on the back of the greenhouse and have the exhaust go by it to help keep it dry.

James Wood : O.K., Got it, by now you are gathering materials to make your 1st test Rocket Stove outdoors, to prove to yourself that it works !

You are into Specialty growing, and doing so in an artificially created high moisture content area! This is a good spot to jump in, in an 'ordinary'
Build we start out with an undermost layer, leveled and insulated, and then using bricks, or other stuff, we create a base that we cover with Cob !

1st we seal up all potential leaks, then add insulating cob followed by structural cob, that contains Straw to help bind it together, you could use
chopped fiberglass if you have a boatbuilder friend! Followed by your finish layer, probably a high lime content finishing plaster !

Due to the high moisture content of the air, we need to protect the cob from getting wet and staying wet, and a finish coat that seals perfectly
can cause the cob to slump. This is something that we will need to work at !

If we collocate the Rocket stove to a separate but attached building we can bury the horizontal pipes in the floor of the greenhouse and call that
our thermal mass. Air drawn from/thru the Attached Rocket Stove Building can be used at least part of the time to temper make up air ! This is an
area outside my wheelhouse, only you can determine how to protect against molds and smuts !

The height of the barrel is totally dependent on the height of the Heat Riser, with a taller Heat Riser you have greater draft and gas speed! The
barrels top surface can get red with temps upwards from 1100F, the barrels sidewalls usually get a coat of Cob About where the surface temps
are ~ 500F, this being a general rule !

Check out page 24, where they talk about off setting the Barrel to direct the heat to where you want it in the surrounding environment, this Off
Set should set over the top of the transitional area in the Rocket Stove Base that receives the hot gases from the bottom of the barrel, turns it
at right angles and channels it to the Round horizontal pipe for the thermal mass !

I really like this one, check out page 36 (small 'd') where they talk about the fact that the surface area of a small drum most radiate off the same
amount of total heat energy as a larger barrel must , and does so by radiating at a higher Temperature ! This is the reason that when your 3 year
old wants to get up in your lap for a cuddle, their smaller Surface Area to Mass requires that they radiate their excess heat at a slightly higher
Temperature, A little heat radiator in your lap !

There are companies that want to sell you a Rocket Stove core that includes models scaled down to as small as a 4'' discharge into the horizontal
run. I have always tried to never by the 1st or the last of any thing, so I am not ready to recommend any pre made 'Rocket Stove Cores' and 4''
has been a distant goal for home builds, not the average !

Talking about where you might look for help reminds me to recommend earnieanderica.info. To say they taught me all I know about Rocket Stoves
is an insult to the pair - your can't store much information on an old Texas Instruments T-99 !

You should also take in the information about the 'Pocket Rocket' pages 70,71, and pages 76,77, our local Scout Leader has the kids make their own
'Pocket Rocket' for ice fishing around here usually 2gal. to 5 gal. You will make some thing like it to burn off the paint on your barrel, and any gunk
inside !

I must have missed or misread a part about 'Ram Pumps', though I often call the Rocket Stove a heat pump ! Can you please give me the page #!

There are Hybrid Masonry/Rocket Stove heaters that have a larger burn chamber that allows for batch loading. They usually start with a small fire
getting the internal walls of the combustion chamber red hot,and then allowing the stove to be reloaded, the working theory is if the wood chunk bursts
into flame but smokes, the fire needs more Oxygen, and if it bursts into flame and burns cleanly the oxygen is close to correct !

There are so many changes coming so fast in the Rocket Stove / Masonry Heater area, that I really fear that I will soon be left behind !

For the good of the Craft ! Be Safe,keep Warm PYRO Logically Big Al !

There is

After watching a YouTube video, I did make a simple "21 brick" one about a year ago using 100% scrap stuff. Even managed to get some used firebricks. It is pretty basic - I just piled the bricks together, no mortar. It worked very well for cooking things using minimal input. It was also a fun way to get rid of yard waste. Until recently, I wasn't thinking about using one of these to heat anything, thermal masses, etc. Lots to learn.

James Wood : You're really going to like this one ! Go to You Tube and type in 'web4deb', I wanted you to scroll down to the 'Rocket Stove Playlist'',
but I bet you'll get lost on the way to there !

For the good of the Craft ! b.s.k.w. PYRO Logically Big AL

Wow! Those vids will keep me busy for a while! Thanks.