Rocket mass heaters

[Chris Leon]

If you're interested in heating a space for not much money, ie bit's of dead wood etc., check out, Rocket stoves or rocket heaters or rocket mass heaters on youtube. I reckon it's a good solution for greenhouses in cooler climates... Make sure you watch them and understand how they work. It's genius!

 

Chris

[George]

Good luck with it.  I'm off my stove kick for the time being but I had a lot of fun with it for a while.

Mike Creuzer said:

I've been working with a Rocket Mass Heater (RMH) this fall and winter in my garage. Details are at http://mike.creuzer.com/topic/builds/his/rmhf

[K Schreiber]

Thanks for the input, Mike.

Mike Creuzer said:

That would be cob (basically mud mortor) used underground.

I would just use it. Maybe mix it on the sandy side so it will drain well. It's not like it will go anywhere. Straight sand will have too many voids and will insulate too well, you need the clay and silt to fill those voids.

George said:

Please explain a bit for us slow people.  What is below grade cob?

K Schreiber said:

  how do I protect below grade cob from ground moisture?  Any thoughts?

[Mike Creuzer]

If you fire the stove after the below grade cob  gets wet, you will need to dry it out before it will hold heat again. Just means a couple hours more of firing I suppose. Repeated wet/dry cycles will probably cause it to crack a fair amount, but I don't think it's really going to cause problems. 

(I am not a cob expert, so take what I say with a grain of salt)

K Schreiber said:

Thanks for the input, Mike.

Mike Creuzer said:

That would be cob (basically mud mortor) used underground.

I would just use it. Maybe mix it on the sandy side so it will drain well. It's not like it will go anywhere. Straight sand will have too many voids and will insulate too well, you need the clay and silt to fill those voids.

[K Schreiber]

I'm more concerned about the piping, but I've been reading Evans book, Hand-Sculpted House, all about building with cob, and it's given me some ideas about how to provide really good drainage, etc.  Of course, I won't be able to do anything until late spring, after the ground thaws, although even then, I plan on working on my chicken moat first.  Maybe later in the summer...

Mike Creuzer said:

If you fire the stove after the below grade cob  gets wet, you will need to dry it out before it will hold heat again. Just means a couple hours more of firing I suppose. Repeated wet/dry cycles will probably cause it to crack a fair amount, but I don't think it's really going to cause problems. 

(I am not a cob expert, so take what I say with a grain of salt)

K Schreiber said:

Thanks for the input, Mike.

Mike Creuzer said:

That would be cob (basically mud mortor) used underground.

I would just use it. Maybe mix it on the sandy side so it will drain well. It's not like it will go anywhere. Straight sand will have too many voids and will insulate too well, you need the clay and silt to fill those voids.

[Terry Clark]

So my question to everyone is; when you have to clean the chimney do you have to dig up all the pipe?  What about soot and creosote? Or even a chimney fire?

[Mike Creuzer]

Make sure you ad cleanout Ts in enough spots so you can clean it as necessary.

If the Rocket Mass Heater is running properly, you shouldn't have much soot or creosote buildup. They are designed to not be able to be damped down, which is how soot and creosote are formed.

[markaponics]

Instead of Rocket Stoves... take a look at wood gassification. Create heat and gas. here is an excellent link.

Wood Gassifier

[Meg Stout]

I've got a simple and inexpensive rocket mass heater in my yard - plan to (finally) hook it up to the greenhouse later this summer.

I used cinderblock sections for the chimney inside a 55 gallon (food grade) drum. The whole thing is supported on cinderblocks with gravel and sand to keep the gases from going anywhere other than out the exhaust pipe. The exterior is just stacked brick, so I can easily dismantle the firebox to clean out ash right where the fire burns. I also have a T at the exit where I can clean out ash at the exit of the rocket mass heater itself.

I have constructed a cinderblock base for my floating raft bed through which the exhaust pipe will run (the larger hole in a 12"x8"x16" cinderblock can accommodate 6" pipe). I'm not sure how much thermal transfer I'll get, but it shouldn't hurt.

Because my greenhouse is small, the RMH lives outside the greenhouse itself. In future I may redesign my system so the RMH can live inside the greenhouse.

Here's an early blog post about what I was doing:

http://365aquaponics.blogspot.com/2012/02/keeping-things-warm.html

[Glen McDonald]

Hi Chris,

Are you using a rocket mass heater to heat your greenhouse? If so how long is your horizontal chimney run? Do you have a site or content you can point me at that may answer this question for me.

Thanks

Glen

[Don Stark]

I built a rocket stove in  my greenhouse last year, did not build a full blown mass heater.  I wanted to see how well it would work before I put all the cobb and such in place.

The Rocket Stove was fun and entertaining, burned lots of sticks and debris around the place.  

Heated water on top and thought it would be an acceptable solution,,,, until I realized how long I would have to be there feeding the stove every 10 - 15 minutes.

I estimated that it would take hours feeding the stove in my greenhouse while I was NOT in my home feeding the woodstove and working on other projects.

I abandoned the idea of a rocket mass heater in the greenhouse: to much space devoted to mass, to much time to keep heat up and was hoping a creative idea would present itself.  And it did, Rick Stillwagon has a non-electric pellet stove that is amazing.  I think the cost is about a dollar a day and will only take a few minutes to feed the hopper.  see it @ http://www.zephyrgreenhousesystems.com/pb/wp_9e4a4a4c/wp_9e4a4a4c.html

saves space and perhaps more important to me is the time it will save.

I love the rocket stove and think they have a place in the world.  The RMH have a place, and I might build on in the house to heat living space yet I have not seen the practical use in an AP Controlled environment.  I welcome any comments, disagreements and advice.

[Matthew Smith]

Another interesting heat source for winter is to build a compost pile inside the greenhouse that is at least one cubic yard in size. They release quite a bit of heat and CO2 for the plants. The internal temperature can easily reach 160 degrees F. It is a nice way to create a nice steady heat that you don't have to go stoke all night long.

 

For the rocket stove you are going to want to add plenty of thermal mass around it to store the heat and not in the form of water. We tried a similar idea with a hot tube in a greenhouse in northern wisconsin. Not only did we have to keep the fire stoked all night long but we had so much condensation on the glass that it kind of defeated the purpose of it all.

 

I've also heard of people keeping small animals like rabbits and chickens in the greenhouse. Those little guys release quite a few BTU's and all you have to do is feed them greens from your aquaponic system!

Don't let the chickens into the compost pile though because they'll disperse the pile all over the place and all its heat along with it.

 

matt

[Rob Torcellini]

I didn't realize there was a RMH on here....not sure how I missed it! 

I have a RMH in our new greenhouse and used it for the first time last winter....I must say it was quite impressive to see how efficiently it burned.  Here are the videos that detail the installation:

Sorry Matthew, but I have to disagree with using compost heat for the following reasons:  1)  Even though it produces heat, it's not a high density heat.  If you try to heat a greenhouse with something that's only 160, it will quickly loose its thermal mass of heat...  Those little bacteria just can't keep up with the demand.  2)  You need a LOT of compost to keep up with the heating, I would rather use that space to grow plants.  3)  You can't regulate the heat (turn it on and off).  If you have a warm spell, you'll have to vent the building.  At least with a RMH, you can shut it down if there's going to warm up.  4)  Compost invites fungus/bugs/mice/rats.   I think it's best to keep the compost pile outside and away from the greenhouse.

I also feel the same about putting livestock in the building.  They don't produce enough BTUs to heat a building, consume large amounts of food (hopefully scraps), and you increase the risk of having warm-blooded pathogens getting into your system.

just my 2 cents worth....