Greenhouse Rocket Stove

I need to build a shed out back and I want to put a rocket mass heater in it.
I am thinking about an enclosed porch where the feed part is and the fire will be like under the wall into the building. The enclosed porch will be on the South side of the building and it will be a dry place to store bundles of firewood.

That way the air that is feeding the fire will not be coming from inside the building. Just a short distance inside the wall will be the fire loop then the exhaust into the bench that will be on the West side then on the North wall before exiting out through the East wall.

This would just be a testing mass heater. The idea is to head back there on a cold winter day and see what the mass heater will do. If I keep a fire going for 24 hours or until it is warm in there then just let the fire die down to see how long the warmth lasts. Ultimately what I want is to build a greenhouse with one in it.
If I could just feed it several times a day and the mass would carry it through the night I would be so happy.

Also I must ask if anyone thinks water can be the mass.
Originally I was planning to use an old cast iron wood stove I have that has a water jacket around it and two threaded holes to plumb it up with 3/4" pipe. I was going to place 12 plastic 55 gallon drums around the greenhouse with the grow beds on top of them. Insulation wrapped around all of the barrels would make almost all of the heat go up through the grow beds. I was going to push water through the stove then through all of the barrels. The cast iron stove would have been radiating heat into the whole greenhouse.

I know the rocket stove will burn a lot cleaner and get more heat out of the wood. If I can wrap enough copper line around it do any of you think the water barrels would be okay to use?

I have insulated double pane sliding glass door panels to use for the glass parts of the greenhouse. If I had row covers on the grow beds just think about all of the heat that would be stored in those barrels radiating up through the grow beds then it is trapped under the row covers.

My idea would be a 3/4" Galvanized pipe to the rocket heater then to a header pipe with a lot of smaller 3/8" copper lines going around and around the rocket stove before heading them all back into a header pipe of Galvanized 3/4" then around to all of the barrels. I do have 100' of 1977 3/8 copper that has never been out of the cardboard boxes. I also have an old pressure tank that I would use upside down as an expansion tank in the system.
I probably would just drill holes in the header pipes and tap them to fit 3/8" pipe to flare adapters.

Alan in Michigan
A Michigan Redneck

Alan Bowen : With less than 50 days left in the year you may get the 'Lurker Award' ! Congratulations , Welcome to Permies.com/richsoil.com and the Rocket and Wood Stoves
Forum Threads ! when you originally started popping in for a look we were at 20,000 members the largest English speaking Permaculture group in the world, we are now at
28,00 fellow members world wide, eager to talk about what you want to talk about .

Alan Bowen wrote:I need to build a shed out back and I want to put a rocket mass heater in it.I am thinking about an enclosed porch where the feed part is and the fire will
be like under the wall into the building. The enclosed porch will be on the South side of the building and it will be a dry place to store bundles of firewood.

This is important, Greenhouses are by definition areas of high humidity, we always want our wood as dry as possible and this is one way to make that happen>

That way the air that is feeding the fire will not be coming from inside the building.

But, remember the heat that flows Through the horizontal chimney is captured in the Heavy Dense Core of the Thermal Mass , It is Not vented out the final vertical chimney,
therefor it is not lost!

Just a short distance inside the wall will be the fire loop (?)

Perhaps you are taking about the Heat Riser and the TWO gas streams 1) the very hot rapidly rising gases within the Heat Riser and 2)the much cooler gases that are in

contact with the surfaces of the barrel, and are now thickening, heavy, dense, and falling vertically down the exterior of the Heat Riser ! There is No Loop!

(Then the exhaust into the bench that will be on the West side then on the North wall before exiting out through the East wall.)

Sorry, I got lost about the time I left the RMHs base -and before I got to the Horizontal pipe thru the Thermal mass! This area the Transitional Area is critical to get right !


This would just be a testing mass heater. The idea is to head back there on a cold winter day and see what the mass heater will do. If I keep a fire going for 24 hours or
until it is warm in there then just let the fire die down to see how long the warmth lasts. Ultimately what I want is to build a greenhouse with one in it.If I could just feed
it several times a day and the mass would carry it through the night I would be so happy.

A couple of hours a day maximum tending to the RMHs needs by ear with no more thought than you would use in adjusting your glasses = 20 - 30 hours of heat !
this is much later, even days later after the core, the insulation, and the cob have all dried out !

Also I must ask if anyone thinks water can be the mass.

For your first RMH inside a Greenhouse - 55 gallon drums at ambient temperatures during the day will rarely fall 10 degrees over night, elaborate plumbing is rarely

needed if you are just trying to add a month of greenhouse use at both ends of your Growing season !


Originally I was planning to use an old cast iron wood stove I have that has a water jacket around it and two threaded holes to plumb it up with 3/4" pipe. I was going
to place 12 plastic 55 gallon drums around the greenhouse with the grow beds on top of them. Insulation wrapped around all of the barrels would make almost all of
the heat go up through the grow beds. I was going to push water through the stove then through all of the barrels. The cast iron stove would have been radiating heat
into the whole greenhouse.

I know the rocket stove will burn a lot cleaner and get more heat out of the wood. If I can wrap enough copper line around it do any of you think the water barrels
would be okay to use?

This is a poor place to try and extract heat, the water jacket will tend to hold temperatures at the boiling point of water which is well below the temperature
required to burn creosote, and still capable of turning water into steam !!

After the barrel - within the first 5' of the horizontal pipes run through the Thermal Mass is usually a safe area to run large diameter tubing as part of a
non-presurized system!

I have insulated double pane sliding glass door panels to use for the glass parts of the greenhouse. If I had row covers on the grow beds just think about all of the
heat that would be stored in those barrels radiating up through the grow beds then it is trapped under the row covers.

The lower the thermal mass is positioned the more effective the row covers will be !

My idea would be a 3/4" Galvanized pipe to the rocket heater then to a header pipe with a lot of smaller 3/8" copper lines going around and around the rocket stove
before heading them all back into a header pipe of Galvanized 3/4" then around to all of the barrels. I do have 100' of 1977 3/8 copper that has never been out of
the cardboard boxes. I also have an old pressure tank that I would use upside down as an expansion tank in the system.I probably would just drill holes in the header
pipes and tap them to fit 3/8" pipe to flare adapters.

Ask a Firefighter! When you reduce the inside diameter of the pipe by !/2c you reduce the Sq. inches to 1/4, and lose even more proportionally to friction loss, so the
actual flow is closer to 1/5th! In this case the 3/4 pipe you started with is too small for the job you are asking it to do !
Alan in Michigan
A Michigan Redneck

Thank you for the reply.
My first one will be in a shed out at the back of my five acres.
No water barrels out there.
I will follow all guidelines in doing it the best I can because that shed will be carrying solar panels on a steep roof.
That is to help keep the snow off the panels.
The batteries and such will be in the shed and the inverter to power the fence charger will be there.
I am working on two of my five acres to get it in shape to start growing feed for pigs and chickens.
The electric fence will hopefully keep the deer and coons out of the crops.

The green house will be mounted on skids and it will mostly be used in the winter.
Not to extend the seasons but to give me salads all winter.
That will be up here in the yard near the house.

So are you saying I shouldn't wrap copper tubing around the heat riser?
How about around the outer barrel?
I really do want those plastic barrels full of water with grow beds on top of them.
However I can get a rocket stove to put heat into those barrels that is what I want.

I have these cool pin cherry trees.
If I cut one off during the winter while all of the sap is down there in the roots that next summer the stump will be full of small branches that each will end up as tall as the last tree had been.
This time though it will be a bush.
I will do four of them and if I let the bush go a year or two it will provide an amazing amount of rocket stove fuel.
The first year cut will provide fuel for my wood stove in the basement.
I am pretty sure I am safe in saying I could go out right now and tag thirty of those stupid trees here. It is time to make them work for me.

You got lost?
Walk in to the porch the feed tube is on the left.
The bundles of firewood is on the right.
Go through the door into the shed and the barrels that make up the heat riser and the outer barrel are on the left.
The bench goes down that wall and across the end wall before heading out the far end of the right wall.
Please tell me the critical part about the transition area.
Or give a link to the best info please.

I will not need the rocket mass heater in the shed during the summer and I will not need the electric fence in the winter.
I will love that shed in the winter for quiet time reading though.

Wow, I just read the RMH, fresh air intake, why suck out warm air from inside?
topic.
This really makes me wonder about my idea to feed it from the porch.
I like the last comment I read about routing a pipe of outside air through the bench into the room so the air is warm and then just using room air for combustion.
I would leave the end of the incoming air duct sticking out far enough to slide a good cap on it when the stove is shut down.

Alan I just added to the post on outside air, this holds true for you especially the part about going to Rocketstoves.com to download a PDF copy of
Rocket Mass Heaters

My comment on barrels was to point out that while placing you young greens on top did make sense, the barrels would literally be at the same temperature
at ground level, making it easier to cover with a row crop cover, if the ground is already warm then they row cover protects the plants without trying to
maintain an artificially high temperature within the rest of the greenhouse !

You talked about placing your greenhouse on skids, and then you mentioned wanting solar panels on that roof, Solar panels do not travel well when moved
while mounted on wheeled vehicles, on skids is a little to close to subjecting them to earthquake tremblors, something NO insurance company would cover !

For a michigan location to have winter salads your greenhouse will need to be attached to the House or be part of the house, and you will be paying an
increased price in balancing the thermal energy load to your house and greenhouse, with a very clever design you may break even !

The earliest place to extract heat from your Rocket Mass Heater without the circulating water adversely cooling the RMHs fire is after the Barrel at the start
of the Horizontal flow through the thermal bench, here the temperatures start at 500ºF, this location is hot enough to cause water circulating in your pipes to

''Flash to steam'' Think Boston Marathon Bombing with more casualties, and more full thickness full body burns !

Yes I understand about how to trim trees to promote there rapid regrowth and near perpetual youth if properly harvested, you are talking about Coppicing and
Pollarding young trees ! The correct harvesting, especially for hardwoods is about every 4-5 years ! While it varies from tree species to tree species, that is the
Norm!

I am still lost ! Perhaps a quick sketch ? We have not settled on the size or the location of your RMH and the only advice I can give you now without specifics
is the Transitional area should be 3 Xs the Cross-sectional area of the Burn Tunnel, gradually forming a reducing funnel shape like the bell shape of a trumpet as
the vertically falling gases from the outside of the heat riser flow into the transitional area and then out to the Thermal Bench !

For the Good of the Craft! Big Al

Alan B : O. K., A little miscommunication happens in the best of long distance communication !

The problem with trying to take heat off of the drum is that most of it will be radiating heat off of its self at a temperature that is well above the boiling point of water.

You can not rely on any system that includes any valve that can be closed, and even whith a system that has a water circulating pump it impossible to create a Boom
- Squish event With you or your family as the Squish !

Approximately 40% of the heat produced by a well made Rocket Mass Heater RMH comes off of the barrel, normally the rest of the heat flows out to the Thermal mass

The primary job of the barrel is to shed that heat, without the barrel doing its thing correctly there would be no Horizontal feed to the Thermal mass !

The Greatest amount of the Heat is in the top 1/3rd of the Barrel ! For the Good of the Craft ! Big AL !