Greenhouse heating invention

[Mark in Texas]

Wood pellet heaters are fairly cheap, super efficient and can be easily regulated.

[SeaWalnut]

A 6 inch rocket stove core sells for @ 600 dollars .And its only the core not the whole stove.http://www.dragonheaters.com/6-dragon-burner-rocket-heater-core/
That its not cheap at all and i prefer to build my own and my goal is to use irregular wood ,branches ,not pellets or wood chips.
In my rocket stove i can use pellets,wood chips and even corn grains wich are probably cheaper than pellets but i have free wood branches so il be using those.
I also have gas pipe right next to the dome and my house has gas heating central but altough the gas is cheap i want to use wood because its free.

Here is the riser of my rocket stove before being cast from refractory cement and perlite.
You can see the stainless steel(304) rebar and on the bottom i made a snail shape that will create a vortex of fire inside the round core riser.

As you can see,my core riser of the rocket stove its round and will have the vortex inside ,better than the USA made core i posted in the link above wich has a square riser not suited to have a vortex.

[Mark in Texas]

OK, but can you put that thing on a thermostat? 

[brian]

I had never heard of those YTONG bricks so I was reading about them.  I don't think the insulation value is very impressive... if I'm reading this right  (https://ytong.co.nz/wordpress/?page_id=54) the R-value is only 0.2/in, just slightly more than plain concrete and far, far less than something like fiberglass (~R3.5/in)or foam (~R5.0/in) - foam isn't fire resistant, though.

This type of thing is common in the US though, sold under name refractory-brick or fire-brick, simply not that brand

[behlgarden]

why not use lump coal? once smoke is out, the red hot lump coal can stay hot and give heat for 6-8 hours.

[SeaWalnut]

I can put it on a thermostat but it will complicate the design by a lot.
Its not easy but i can do it for sure .In that case il have to incorporate a small gas burner just to light the woods automatically,a battery and controllers.
I accept somme 10-15 degrees difference during day and night so il do t need a thermostat .

Brian, the Ytong bricks have such insulating power that they are almost like rockwool or glass wool insulation per thickness.
Also one thing to have in mind is that glass wool insulations are normally 3-4 times thinner than a wall made of Ytong and the result is that a Ytong wall gives usually double R value than glasswool insulation .
They are fire bricks but they are not used much for building fireplaces because of the insulation= you would make fire and these bricks would not let the heat to pass through them efficiently to heat the home.

This foundry is made of Ytong bricks and on the outside you can touch it bare hand while everything glows red on the inside.Thats a verry big insulation power.
We make buildings out of this material here and in any otther parts of the world except USA and Canada .

[SeaWalnut]

why not use lump coal? once smoke is out, the red hot lump coal can stay hot and give heat for 6-8 hours.

Coal made from fresh wood( charcoal not the fosilised types) its verry low efficiency.
I would have to burn a double ammount of wood to make the charcoal and charcoal lacks the gasses that wood has .
In the end from 3 cubic meters of wood ,if i turn it into charcoal i would get the heat equivalent from just 1 cubic meter .

[behlgarden]

I was looking at anthracite coal. It's the most sense, almost non toxic and lasts a long time.. this is used specially for space heating.

[SeaWalnut]

I was looking at anthracite coal. It's the most sense, almost non toxic and lasts a long time.. this is used specially for space heating.

Anthracite is fossil coal.Thats good to burn but its not free ,costs monney.
My plan is to use small twigs and branches that will be held together in a machine like a rolling cigarette machine and they will be tied using plastic PET bottle rings wich will be heated to shrink.
I will be making a soird of long briquettes from branches using reciclable materials that il get for free.

[SeaWalnut]

I made a new and smaller rocket stove with the feeding hole 6X6 cm(3X3 inches).
This burns a ridiculous small ammount of wood but its efficient,no smoke on the exhaust and reaches such high temps that it made the fire brick shrink and crack.
Altough the bricks cracked ,its no problem,they still work as normal.
I welded a metal housing for the bricks made of steel ,so that there is little tension on the bricks.
Because it burns such little wood i will keep this stove running non stop all the winter.
Will post pics after i paint the new metal housing and after i add the stainless steel heat exchanger( made from a beer keg/ barrel).

[SeaWalnut]

Just bought somme 2x1 meter stainless steel shet to make the chimney of the stove.
It thin just 0,3 mm but i dont need to be thicker because it will be a short chimney and thickness is for structural stability.
Will be double layer of stainless steel with rockwool inbetween.
I choose it this thin because i hope it will be easyer to work with and make the bends and seams.

[SeaWalnut]

I put the little rocket stove in function .For this winter will stay as it is meaning that il not install it outdoor iet and il not make the heat teansfer on air through the earth floor.

With regular vertical chimney it smoked a lot until it made the chimney warm so i let it with horizontal chimney and works great.
It seems like its too lityle to heat the greenhouse ,but its build for continuous use non stop ,day and night so the heating can take a while with such device.


The power its probably 3 kw wich is quite little but its made for continuous use at full strength.

[Kevin Jones]

Looks good!
How will you feed your combustion material (wood, etc) into the stove?
Also... is that woven greenhouse plastic I see on your dome?
If so... how is that material to work with?
I've been looking into using that material as well.
Thanks
Kevin

[spaugh]

Why dont you bury the exhaust and build a thermal mass around it?

[SeaWalnut]

Why dont you bury the exhaust and build a thermal mass around it?

Because the stove is soo well designed that the exhaust as you see it stays cool to the touch.
If i add a fan to chill the bell as my original intention was,then the exhaust would be even cooler and im talking about like 8 hours of continuous use.

[SeaWalnut]

Looks good!
How will you feed your combustion material (wood, etc) into the stove?
Also... is that woven greenhouse plastic I see on your dome?
If so... how is that material to work with?
I've been looking into using that material as well.
Thanks
Kevin

THX
The wood i fed it vertically @ 40 cm long and in more than one pieces at once ( preferably smaller sticks,twigs,grape wine cuttings ,etc,the softer essence of the wood the better).
They burn at the lower end of the sticks and slowly melt and fall little by little in the burning chamber on their own.
40 cm length hardwood lasts @ 1 hour.

The material on the greenhouse is double walled polycarbonate,4 mm thick.Soon i will finnish adding another layer of also double walled polycarbonate on the interior ( 3 mm thick) with a gap inbetween the 4 and 3 mm policarbonate sheets of 5 cm.
I loose somme of the light that way but i get good thermal insulation.

That woven transparent material i think its made of resin and contains fiberglass.I worked with it and it flexes a lot,lacks the stability of the twin wall polycarbonate and its also brittle and not verry much transparent to the point that im not sure its suitable for a greenhouse.Also the resin will get yellowish over time.

[spaugh]

Why dont you bury the exhaust and build a thermal mass around it?

Because the stove is soo well designed that the exhaust as you see it stays cool to the touch.
If i add a fan to chill the bell as my original intention was,then the exhaust would be even cooler and im talking about like 8 hours of continuous use.

Interesting.  So does the bell get red hot or how hot is it?  Need to be careful not to touch it?  Does it radiate too much heat for a plant to be near it?

[SeaWalnut]

Why dont you bury the exhaust and build a thermal mass around it?

Because the stove is soo well designed that the exhaust as you see it stays cool to the touch.
If i add a fan to chill the bell as my original intention was,then the exhaust would be even cooler and im talking about like 8 hours of continuous use.

Interesting.  So does the bell get red hot or how hot is it?  Need to be careful not to touch it?  Does it radiate too much heat for a plant to be near it?

The bell gets 150-180 degrees C right in the middle of the top part and gradually lowers to 60-70C on the lower part.
The exhaust gets 40C temp.
It doesnt glow red but it will get higher temp after il enlarge the feeding hole a little more in wich case i will install a fan and somme tubing to move the heat from the bell and chill it.
Plants can be kept near this without a problem .

[spaugh]

Why dont you bury the exhaust and build a thermal mass around it?

Because the stove is soo well designed that the exhaust as you see it stays cool to the touch.
If i add a fan to chill the bell as my original intention was,then the exhaust would be even cooler and im talking about like 8 hours of continuous use.

Interesting.  So does the bell get red hot or how hot is it?  Need to be careful not to touch it?  Does it radiate too much heat for a plant to be near it?

The bell gets 150-180 degrees C right in the middle of the top part and gradually lowers to 60-70C on the lower part.
The exhaust gets 40C temp.
It doesnt glow red but it will get higher temp after il enlarge the feeding hole a little more in wich case i will install a fan and somme tubing to move the heat from the bell and chill it.
Plants can be kept near this without a problem .

Nice, you can cook on it. 

Honestly your rocket heater is the coolest thing I have seen on this site in a while. 

[lebmung]

I loose somme of the light that way but i get good thermal insulation.

Maybe 20-25% light lost, not a problem for winter, but for spring/summer is a problem.
Plants will grow taller with less branches, elongated plants, weaker.
Shade plants will do fine. But any fruiting trees will need more light. Consider that some triangles on south side be made of glass or clear plastic (bad insulator for long IR waves) and on top ( for summer)
High temperature with low light is very bad idea. Not a problem for containers, just move them out.

[SeaWalnut]

Ideally would be to have a layer of the double wall removable for the summer but its too complicated with that manny triangles like my greenhouse has.
On a rectangular greenhouse should be simple and worth it for the lack of condensation in winter and the heat saved (lots of heat).

Today,in a hurry i just made this contraption.
A 4 feet(120 cm) long tube that sits on top of the stove .
Its filled with wood tied together with small adhesive tape and the wood slides as it burns directly into the stove feeding chamber.
On the top part of the pipe i glued a cap with a small hole in it so that it doesnt act as a chimney and draws the flames through it.
The small hole on the top cap of the pipe is to let the gasses escape in case somme flammable gasses build up in it (it could explode).
Its just an experiment and keeps the fire roaring for 1,5 -2 hours.
Best to make such experiments outdoor but winter caught me and i have to heat the greenhouse as i can.
Its relatively safe just sometimes it jams in wich case the wood estinguish itself thanks to the draft the rocket stove makes.
Will have to invent something better than this  .

[Mark in Texas]

That really is cool but curious, how easy is it to regulate temps in the greenhouse?   What are you growing now?

Good luck

[SeaWalnut]

The temperature can be regulated by adding less wood branches and thicker,lets say 2 thick branches burn 2 times slower than 5 smaller branches/ pieces of wood.
But for the moment im not interested in keeping a stable temp until i make the stove to work continuously.The new wood feeding mechanism its my priority and to finish installing the second wall of polycarbonate for better thermal insulation.
Right now i have inside the greenhouse a strawberry guava thats almost 2 meter tall,a tomato plant in a bucket ,my gevuina seedlings,Feijoas,2 tropical Sesbania Punicea,Loquat seedlings,1 Toona Sinensis seedling and one acacia silver wattle seedling.
Most of these plants are temperate except the Sesbania Punice wich its a true tropical plant and doesnt do to weel but the seedlongs are still alive and pushing growth.
Cant get to make the temp go past 10 degrees C when outside was 0C with the stove but i also opened the door manny times because of working and the greenhouse doesnt have installed the second layer of insulation iet.
Plus,the stove was in use only during the day.

[Daintree]

Is it 10 C on the floor, or at the top? Maybe you need a fan to push the warm air down.

Carolyn

[brian]

Yeah a large ceiling fan at the top might help a lot