Less heater mass weight without thermal loss - ideas, anyone?

My quandry is this: you need mass to store heat, but does it have to be cob, concrete, etc.? I would love to install a rocket mass heater, but the weight of 3 tons (as mentioned in Ernie & Erica's video footage) makes me hesitant. That's the equivalent of parking 1-2 cars on one side of my living room, and I don't know if the floor can handle that. So, is there some way to lighten up the weight of the mass without drastically trading off the thermal benefit that makes these things so fabulous? Would adding fiberglass threads, chunks of pumice or whatnot be enough to reduce the heft of a RMH without it becoming just another woodstove?

The reason why I ask is severalfold. Obviously, I want to utilize this tech, but I have friends who want to install these in their trailers, RVs and other places where weight is a big issue. Also, the "sneaky heat" option doesn't work for everyone, and you want something attractive and permanent, but don't want to supplement other structures to make up for that weight.

All suggestions are welcome!


"It's pretty fucking awesome to be me." - P. Wheaton

Well, if you don't need the slow and continuous release of heat, you could look into bells. Over here, in France, i have access to pozzolan chimney elements which are resistant up to 400C°. Let say you use twenty aranged in double bell, you have 840kg, plus top and bottom plate. http://www.beton-thebault.com/upload/Boisseaux.pdf The other advantage, is that you have a tall bell, and it saves space. Peterberg was even saying, skip the barrel, and use one of the bells as a barrel. That was for an horizontal batch rocket.

Satamax Antone wrote:Well, if you don't need the slow and continuous release of heat, you could look into bells. Over here, in France, i have access to pozzolan chimney elements which are resistant up to 400C°. Let say you use twenty aranged in double bell, you have 840kg, plus top and bottom plate. http://www.beton-thebault.com/upload/Boisseaux.pdf The other advantage, is that you have a tall bell, and it saves space. Peterberg was even saying, skip the barrel, and use one of the bells as a barrel. That was for an horizontal batch rocket.

I'm not quite sure how that configuration would work based on the diagram in the link...do you mean use them as internal filler where the cob and mud would be, as the vent pipe, as the chimney? Are there any diagrams where these bells are shown installed in their regular capacity? Forgive me, but I don't have any understanding of pozzolan chimneys (sorry)

Check for .skp files

http://donkey32.proboards.com/index.cgi?board=experiment&action=display&thread=511

You could also check this for bell and less mass.

http://donkey32.proboards.com/index.cgi?board=experiment&action=display&thread=560