I think I've read through all of the RSMH links on permies.com, I've listened to the RSMH podcasts, and I've read "Rocket Mass Heaters" by Ianto Evans. They have provided great information to build a permanent RSMH. But when (not if), we have the expected economic collapse, my plan is to take my family and all my preparedness stuff and head out to a friend's ~80 acres about 130 miles away. The only thing there right now is an open barn, so we'll be staying in a 16' x 32' canvas wall tent. We may need to be in it over winter, so I'd like my family to be warm enough.
Consequently, I want to build a temporary RSMH in the tent that can be dismantled easily and be moved to a more permanent location as circumstances allow. The RSMH will be in the tent on the left about five feet from the door on the left side of the tent and four feet away from the wall on the back side. The 6" vent will be on the ground, come 2-3 feet to the center of the tent then go down the middle of the tent and out of the tent on the right, about 28-29' total length. It will have about six inches of various sizes of rock covering the vent pipe all around it all the way out of the tent, and held in place by chicken wire that is staked to the ground on either side of the rock. I know Paul used a wood box to hold the pebbles in place in his portable rocket mass heater, but I thought the use of chicken wire to hold larger rocks in place would allow better transfer of heat to tent occupants and take up less room.
I have questions about some things I'm not sure of and would appreciate some direction from the RSMH gurus:
1) Since I will need to be able to move everything easily, I don't want to use mortar on the feed tube, burn tunnel, and heat riser. What can I do to prevent smoke from leaking out between the bricks of the feed tube and burn tunnel? Can I wrap them in rock wool and cover that with chicken wire staked to the ground, or can I place rocks over the rock wool to hold it in place? Or can I use mortar and still be able to break the bricks apart fairly easily without breaking the bricks?
2) My heat riser needs insulation, but a perlite/clay mixture will be more permanent and make it too difficult to take apart. On page 94 of Rocket Mass Heaters, 3rd edition, it shows a refractory wool blanket as the insulation in a wire mesh cage. Rock Wool would do the same thing as I understand it. But doesn't the fire get so hot that it would destroy the wire mesh fairly quickly? If so, is there any way to hold the rock wool in place without it being permanent? If not, how can I insulate the heat riser well enough without it being permanent?
3) Will I have to use cob to seal the manifold so there are no leaks, or is there another way that will allow the system to be disassembled easily?
4) Since the vent will be on the ground, does the exhaust end of my vent pipe need to go vertical at all after exiting the tent or can it stay horizontal if it goes out of the tent far enough?
5) If it does need to go vertical again, how high should it go?
6) If it can stay horizontal, how far is far enough out of the tent?
7) Should I place some rocks under the whole length of the vent pipe to absorb heat also, instead of just on the sides and on top of it?
Is a standard vent cap a good way to block the wind from pushing air back through the system, or is there a better way?
Thank you for your help!
Barry Pulley
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