External Rocket Mass Heater

If I am unable to put a rocket mass heater inside the house, due to weak floors, can I put it in a well insulated shed outdoors and bring the heat into the house from there?

Any designs using this?

Should I use air or liquid to transport the heat between the house and the shed?

Would this still be more efficient than using a cast-iron stove inside the house?

Thanks.

Mike, can't you strenghen the floors? This should be the easiest option imho.

Not easily, but it may be an option.

I have seen these "solar sheds" on the web that use a similar approach for storing heat outdoors. It should work with the rocket mass heater, I think.

Does the house have any conventional heating system? A boiler system or forced air system could be co-opted to distribute the heat.
Water has high energy density but has issues related to steam explosions. Moving the heated water requires thermal siphoning or an electrical pump, either of which seem complicated.
Air has a lower energy density but few safety issues, and making a convection or blower based air moving system seems relatively simple.

Do you have a basement? Before I heard of rocket stoves I read some info on simple barrel stoves. The author piled tons of mass on top and around the stove, and burned hot fast fires. He also often placed this setup in the basement of his abode. The heat would rise to the rest of the structure, and the basement, if at all damp, would dry out.

et al :I will try to keep this positive, though I do see problems that need to be worked out, LOTS of research is in order ! With a Conventional Fossil Fueled Forced-air Furnace
you have to have both heat runs to, and cold air return lines from, If you can find any one of these forced-air Units go and count the number of hot air runs estimate the total
number of square ft, Xs 2 for the cold air return and that is the amount of piping you will need for a connection with your 2nd furnace ( this is assuming that the H.E.V.A.C. Con-
tractor knew what he was doing !) for simplicity you will need a second blower package, about 1/3 of the Total area of the Furnace, or a small closet. As all this is for someone
who was asking about placing their new Rocket Stove Outdoors, the total sq. footage of the ducting will have to be considered to determine the size holes you will be making in
the Original Envelope of the home, Placing a R.M.H. in a remote location where it can not be supervised is never a good idea !

Have you seen the MythBusters Exploding water heater episode ? If not you should look at it now, Think the Boston Marathon Bombing with more victims and more total body
3rd degree burns, Fellow Members from the United Kingdoms tell me that Solid fuel boilers are banned over there ! Again remote locations are a bad Idea !

For years our Rocket Mass Heater Workshop instructors have been telling us that placing the R.M.H. in any remote location was a bad idea, especially when retrofitting your
Rocket heater into a Conventional house, and certainly always when considering placing it in a basement ! Most houses are not very tight with tremendous numbers of air
exchanges everyday, so that 1/2 or sometimes worse of your total energy costs are spent on heating cold air that enters your house mostly in the bottom half, while expensive
hot air escapes out through holes in your house ! This is called stack effect, and works against the proper performance of the R.M.H. in the basement! It can fill your house with
smoke, or it can kill you !

1st from the mouths of Rocket Mass Heater Experts, done in a light friendly manner - go to - ' villagevideo.org/products/rmh/scenes ' - you need to watch the second
video, preparing your house for a rocket - though all are worth watching !

The second is a only slightly more technical video from the research arm of the University of Alaska, you would expect them to know something about cold weather housing !
please go to- ' cchrc.org/2013/what-is-stack-effect-and-how-does-it affect-your- home/ ' - pay attention to the remarks at ~5:45~ For the Craft ! Big AL!

Think like fire, FLOW LIKE A GAS, Don't Be the Marshmallow ! As always, your comments and questions, are welcome and solicited PYRO - Logically A. L. !

Great resources as usual Big Al!
I got several conclusions from them:

1.Seal your house from top to bottom
2.You will have air infiltration no matter what you do.
3 Stack effect is a powerful force.

Now all that being said, I must disagree with the received wisdom of always saying no to basement Rocket Mass Heaters.
One of the stated goals of having mass is the ability to store heat, and thus avoid tending the fire. Much like having your washing machine in the basement, a RMH in the basement will not get the regular attention that would make it most useful, but not having it all would make it less useful still.

As for the stack effect,as I have come to understand it a RMH in the basement of a one story home shouldn't be any more effected by stack effect than a RMH on the first floor of a two story home.
If this is correct, then stack effect should not be a deciding factor in avoiding the basement as a location.

A good compromise might be the firebox/heat riser on the first floor with a two story bell rising up from the basement.

Matt Walker has a great simple bell design:Simple Medium Mass Bells


Of course, soon after learning about stack effect I found someone else who needs to know so I am directing the participants of the Basement Rocket Stove thread to this thread.


Thanks again Al for sharing the Knowledge!

William : As a founding member of the A.S.P.C.H.D. ( American Society to Prevent Cruelty to House Dragons, and a fellow Member of the Royal Society to Prevent Cruelty to House
Dragons it is my sworn duty to intervene to stop the unreasoning creation of Rocket Mass Heaters that are poorly made, or worse poorly placed, to be abandoned by their Builder /
Creators.

This not only saves dragons not yet born, but for every planned Rocket Mass Heater that becomes the Hearth of the Home, there you have happy well fed Dragons and owners
singing high praises to the magic that is the R.M.H., and creating new converts who make new homes for THEIR House Dragons !

While I can see the point you are trying to make, just to listen or read it is an unattractive and unwanted chore ! Let us agree to disagree! For the Good of The Craft! Big AL !