My rocket hot water idea

Hi here is an idea ror rocket hot water that i thought id share please give your ideas and criticism but please be respectful.
i am not that keen on having a fire in the house but this could be just outside the back door and have hot water available in the house another coil and pump could be added to feed radiators in the house controlled by a thermostat it would be a little less efficient than a RMH but more controlled heat more like an outdoor wood boiler but more efficient because off the rocket combustion. in my climate i still like hot showers and hot water for washing dishes ect but very rarely need to heat the house. this would allow only heating the house when i want to without needing two separate systems.

For a mild climate where the house very rarely needs to be heated, it sounds like a good general concept. I think it would work better if the riser and the water tank were in the same bigger enclosure. This would give more overall thermal mass to temper the water, and take care of both the need to insulate the riser and protect it from external damage, and make the whole thing look neat (if that matters at all to you).

Your depiction of the water tank entirely inside the bell is problematic, as it exposes the connecting pipes to high heat. For safety and simplicity, I would suggest embedding the tank in the cavity with its top exposed (and insulated), so all piping connections can be accessible and not overheated. (There was a thread here a few years ago by someone in Germany who built a beautiful and well-engineered system like this, inside his house, but I haven't been able to find the thread to share now.) A glycol or oil solution in the tank will let the tank get hotter than boiling water, leading to possible steam explosions or venting. The safest method that has been found is to use plain water, open to atmosphere, in the tank, with pressurized water in tubing coils in that. The tank will never get as hot as the boiling point of pressurized water.

thank you for your input i had the same idea originally of putting the heat riser inside the outer barrel but i think it would take up too much room unless as you say you found some larger container for the bell i chose to go this way as 55 and 30gal drums are easely obtained im not sure of any easily available bigger container.on the other hand it dos'nt necessarily require any metal it could be a brick or cob bell.

agreed exposing the top would give better accessibility and protect piping.

i was in error when i suggested glycerol I knew it decreased the freezing temp but didn't realize it increased the boiling point so much i was under the impresion that it actualy decreased the boiling point thanks for enlightening me.

In a cold climate, antifreeze of some sort would make sense. Where the house rarely needs heating, I can't see much risk for a tank of water.

I found the thread about the water heating RMH in Germany, by Konstantin Kirsch: doubling the power of an RMH by cooling the feed tube!!.

Any updates....bump...the last link does not seem to work anymore? What did you go with to heat hydronic fluid, waste, oil, or ?  Thanks.