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Glenn Herbert
Post     Subject: Heating water for the mass in RMH

As John says, the flame can't go through the water (bubbling up??); it needs to be contained either around or inside the hot gas exhaust path. A water coil always runs the risk of heating too fast and flashing to steam (exploding). A tank which sits on or inside the heated chamber can absorb heat while having enough mass to be stable, and if open to the air it can't explode. A tank with a fire tube inside it, like a gas water heater, might be very effective at absorbing the heat.
William Bronson
Post     Subject: Heating water for the mass in RMH

Over at Donkey32.ProBoards there have been discussions of involving water in the exhaust stream,mostly for the purpose of filtering out what little in the way of particulates that a rocket stove produces.
One fella even bubbled the exhaust through water like a giant bong...
I myself have theorized something like you have described. I call it a "Wet Bell". A bell with water in the bottom,the gas exhaust and inlet located right above the waterline.
A side effect is the potential of preserving from heat damage any Portland concrete in contact with the water.
Heat drives water out of Portland,reversing the process by which it was made. With water always present, tempatures should never get high enough for the concrete to degrade.
John McDoodle
Post     Subject: Heating water for the mass in RMH

the exhaust will have to exit the building regardless.  also the water doesnt touch the smoke or flame path, they typically have thier own chennels, and most people who heat water in this way use a copper coil.  the water in inside the coil, and the flame is outside.

i remember a fellow forum member "FStyles" ran his exhaust through a hot water tank, and used the water as the mass, i thought it was a good idea.  his post is called "first rocket stove heats water" or something like that, check it out maybe.   water as a mass retains heat for quite a while.  if i turn off my propane hot water tank, the water stays hot for days.  so water can make a great mass, if you can somehow efficiently capture it.  

also many people whit aquaponics and greenhouses use wood burning rockets to heat water.  however, you will need to understand how these stoves function, and you will need to exhaust outside, and create a coil or heat exchanger so the exhaust doesnt contact the water directly, but rather via thermal conductivity like a copper coil.

i suggest you simply look at some of the greenhouse aquaponics stoves here on permies, and get a better understanding of how these rocket stoves work, and how to properly exhaust them.

good luck
Hank Fletcher
Post     Subject: Heating water for the mass in RMH

I was doing some reading last night on a separate  that I got the link to from here on the forum.  It was a post from 6-7 years ago.  In some of the comments below the guys article on his attempt at getting rid of scrap wood from his workshop someone posted the idea of using water as the mass for a rocket mass heater.  All of a sudden the idea hit big time.  I knew that was something that made more sense to me given all factors combined together in one.  Continuing on with reading the comments another idea hit me and then I knew I had to seriously question this idea.

I think given everything else I read, but I really don't know for sure, that this idea would snuff out the flame.  Again, I really don't know given the terms I'm reading and not fully understanding the terms I'm reading.  I've never messed with fireplaces before so I'm a bit ignorant about the full functioning of what makes them tick...yes that sounds stupid.

I understand you can take the heat out of the stove and pipe it into a 35-55 gallon waste basket full of water and heat up the water from the output of the stove to help cool off the temp before sending the exhaust out the chimney.  I was fine with that idea until the more extreme idea hit me.  What about just dumping the exhaust into the chimney?  The water isn't being used for anything other than heat storage.  Come spring I could empty the water out and move the bucket elsewhere for summer storage, heck could use it for a waste basket during the summer months.

Is the idea even feasible or would end up snuffing out the flame do to circulation problems.  I realize in some of the reading that you could run into smell issues, granted I don't have a sense of taste or smell so I pretty much would never no the difference...would the water absorb the smell and let it settle in the water versus circulate through the air above the water.

Like I said a rather radical notion but sometimes my mind does that to me.