New RMH build

First I thank all of you here. Only having my rock-it heater working for the last 6 weeks of the heating season saved me 5-600 $ over the cost of build. Kept me from being poor for several months. Anyways I need a larger one to get me through full on winter this year. I have located some 55 gal barrels with clamp on lids for fair price. Im getting 2 this week. Plan on building 1 for my garage too. Planning on building my j-tube 9x9 inside dim. with 2 6 dia. exhausts. I know you folks are perma culture folks and I RESPECT that but Im not quite there., Bred raised and trained Brittany bird dogs with my dad for 20 yrs.til he died,avid outdoorsman and hunter. But Im a gearhead and have a pair of chopper motorcycles Im working on and I LOVE loud rock n roll. I recently got a 6000 watt DJ system for my home. I earned it by doing online surveys.. Sorry I wanted you folks to know who I am. So that being said. I know many of you need to get into this at a low initial investment as I did also. The cob can not be the best material. I SWEAR I am committed to your cause WTF no smoke boggled my mind for a while. Amazing

Joe, 9x9 is big. How big a place do you need to heat?

Cob might not be the best material, but it has one great advantage, it costs nothing. Mind you, where i am, there's no clay, so i have to do things differently. Since the last time i wrote in your metal rocket thread, i've done a little work on a retrofit, which might be of some interest to you, because of the way i build the core.

http://donkey32.proboards.com/post/11503/thread

This might give you ideas.

Joe,

My impression is that you are willing to spend some money on materials, if it will improve the performance. Do I understand you correctly?

Satamax is using the European equivalent of terra cotta chimney flue liners in those pictures, as far as I can tell. They can take the heat, but only so much at a time. So, we have designed some DIY builds which line the flue liners with dense fireclay brick for heat storage. Dense fireclay material does have better heat storage characteristics than cob. Our blog has a chart of materials used for thermal mass.

Cindy, thoses are "refractory" flue liners. They have some chamotte in them. And so far, they hold nicely. They crack once under the intense heat, to relieve the stress, and that's it. After they expand and contract soundly, and don't chip or deteriorate. They've been burn continuously in the green machine for hours in a row, sometimes more than 8. With no ill effect.

Satamax,

How much are they? Terra cotta flue liners are relatively inexpensive. If these are refractory, they are probably more expensive.

Cindy Mathieu wrote:Satamax,

How much are they? Terra cotta flue liners are relatively inexpensive. If these are refractory, they are probably more expensive.

In italy, on the other side of the border, dead cheap. But they haven't much stock left. I can make an eight incher core and heat riser for 30 euros.

Antone 2100 sq. ft. home love your rocket cook stove conversion. Cindy yes I am willing to spend within reason for improvement. Mainly trying to improve heat storage. And heat transfer both transfer of flue heat to storage and heat transfer from storage to home. Hope to also use some hydro mass with thermo syphon around barrel.

Hope to also use some hydro mass with thermo syphon around barrel.

There are probably not enough BTU's to do both water heating and another type of mass storage.

You need materials which have good thermal conductivity and good heat storage. Many possible materials are included on a chart in a post called thermal mass on the blog in my signature. Dense fireclay brick material is a lot better than cob/clay in both of these areas.