the danger should be small, it will be vented
about the worst i see is melted copper and water running all over
Vented as in a open top? It sounds like a closed system..so do you have a steam vent?
Are you sure the copper will melt before it explodes?
I'm not sure where you are at. Where i am there would be a frozen icy mess outside unless i ran the stove constantly (certain times of year).
If it is for heating the house, why not build the heater in the house and skip the water? You can heat water on top of the stove.
Why not just blow warmed air into the house from the outside stove?
Few things I tried. I used a half barrel beer keg wrapped with hundred foot copper tubing. 3/4" best to help prevent steam formation. I'm using 1/2" now but my pump kicks on at 130F. An adjustable snap switch controls a 12 volt diaphragm pump. It works but it takes time to build up heat. It would be best to have a bulk insulated storage tank to store hot water. I use both wood and solar to heat water. Just a basic rocket with copper between the riser and cap barrel.
Two salvaged hot water tanks with leaks JD wielded. I use them as radiators. I use old garden hose to plumb the tanks. They help release heat in the living area.
Okay here i took a barrel split it down the side. used it as a retainer for lack of a better word. To set a barrel on top of the rocket. I put a hole in top of the rocket cap barrel so that the heat / flame strikes the bottom of the barrel stacked on it. 35 gallon of water in the top barrel. when it gets hot enough a 12volt bilge pump moves the water. Works OK. but this is just an idea I got away from.
Sealed containers tend to blow up if heated.
This barrel is not sealed tight.
Sorry no pix but a idea. The barrel I have on top, I cut it so I had the bottom one third of the barrel now sets on top of the rocket ,secured by the split barrel. In the third barrel I placed 3 coils of copper with coils spaced a little. Filled the third barrel with sand. Now, when I fire the rocket the sand acts as a insulator but when I pour some water into the sand it becomes a heat sink. Transfers heat to the copper very well without the flame and creosote exposed.
for heating the living area why not use a small car radiator with a thermostatically controlled window fan?
OK, just so I'm understanding this, please correct me if I'm wrong:
Picture #1 shows how you wrapped copper pipe around the insulated feed pipe for your RMH. The black thing to the right is the outside of your RMH. It's going to fit over that brick-and-copper-pipe device on the left. As fuel is burned, the heat will heat the water in the pipe.
The black 30 gallon water tank is not part of the RMH. I just had it setting there. While I was trying to figure out how to heat water with the RMH. Using a sealed tank to heat water, not a good idea the tanks sometimes explode. I used a plan barrel to cap the riser.
Picture #2 is just a pair of refurbished water heaters that you use to store the water heated up by picture #1. They don't provide hot water for bathing or any other purpose; they just radiate heat.
I'm using the 30 gallon and 50 gallon tanks as radiators for my outside building. I fire the RMH for about 3 hours before I go to bed. The RMH heats the water being pumped through the tubing and carries it to the two tanks in a closed loop. Its enough to keep the shed warm till morning. I can also adjust valves to heat water in a 500 gallon storage tank that I use to wash dishes. Also use solar to help heat the large tank.
Picture #3 shows your finished RMH. The black barrel on top holds water to be heated. You cut a hole in the top of the burn chamber of your RMH in order to let the heat in to heat up the water in the black barrel. The green thing is not a barrel (anymore), it's a sheath to hold the black barrel to the top of the burn chamber.
Yes. Used pipe strap to to pull the sheath tight and clay / cob to seal the edges. Exhaust stays in the RMH.
Picture #4 is another view of your finished RMH. It also shows where the copper tube from inside the RMH exits the RMH and goes to the two refurbished water heaters.
Questions: What is the water in the top black barrel used for? Did cutting a hole in the top of your burn chamber affect the operation of the entire burn system? (IOW, does the smoke still go out the chimney?)