Mike Leo wrote:How long and how often are you firing it?
One major difference is the mass of the masonry. Before, the steel would heat very quickly and anything it did absorb would be conducted through the wall to the barrel. Now all that mass absorbs heat,a lot more than the steel and instead of passing it on right away holds and radiates it for a long time.
If the cob is still a little wet or the masonry is cold by the time you come back to burn again you spend some energy getting the temps back up. Which would be heat not getting to your coil which explains the perceived drop in performance.
The exhaust is hot enough to where I can't put my hand over the chimney. I can't touch the chimney pipe either right before it exits the greenhouse. I am not using any other mass. It (the exhaust)goes out of the barrel and then out of the greenhouse.
Mike Leo wrote:Is the exhaust still very hot?
Are you using any storage mass after the coil in the barrel?
allen lumley wrote:Wenden K. : I do Not like, nor trust your system, and I Know it is not safe, please take the time to read this as your next several choices will affect your life, and
the lives of people you know and who love you !
A well working Rocket Mass heater quickly and very efficiently produces Temperatures ranging from a efficient 1000-1200 degrees F, 550-670 C, easily seeing
2000 degrees F, with excursions to 2400 degrees F 1300C-ish
Because water Can Not be heated (Except under High Pressure), to temps above 212 degrees F or 100 C without flashing to steam, expanding 1600 Xs, we have
to respect the awesome power at our finger tips ! We call that Moment when water 'flashes to steam' Boom=>Squish !
Please take the time right now to goto-> U-Tube and find and watch the Myth Busters '' Exploding hot water heater Episodes, think the Boston Marathon
Bombing only with more Full Thickness And Full Body Burns !
I expect that your original system seemed to be working better as a water heater before was your exhaust Temperatures were not running as hot, this would be
due to the rapid cooling of your burn temps by the cold water in your other system !
There is NO safe way to run enough water through 50' of 1/2 inch Inside Diameter tubing even using high volume/pressure pumps due to the high friction loss in
the system at that Inside Diameter! With the water in your piping having such long dwell times, and potentially exposed to such high temps, the likely hood of a
hot spot where your water can 'flash to steam' is near 100% !!!
While it would be much safer to build a more conventional Rocket Mass Heater, and then wrap your much larger Diameter Tubing around a thick-walled piece of
metal that is itself buried in the cob of your Thermal Mass to which would buffer the expected initial Temperature -500 F-ish, the temperature spread is still to high
to be safe during normal operation and I could fill a book with ways a seemingly minor flaw in the system could be deadly !
And at this time you have approximately 60% of your heat energy wasted up your vertical chimney, This is the place for your greatest efficiencies to come from!
Hopefully you will be able to independently verify much of what I have shared, and you will be looking for quick easy fixes for these problems, please come back
here to Permies.com where your fellow members can discuss your plans and find BOTH problems and solutions and improvements in your systems ! BIG AL
It ran for two years on the previous system with no ill happenings. Normal temperature of water coming out is about 90 degrees, if that. I just looked it up, the steel pipe I'm using has a burst pressure of 6000 PSI, the water heater in their experiment burst at 330ish. Im not seeing how water in a 350 degree barrel can steam flash and burst 6000 psi pipe, rather than push the water out of the end. It's not adding up to me.
Adam Klaus wrote:Just going to second Allen Lumley's opinion. I think you have a potentially explosive situation on your hands. Your system may be an 'open loop', but when a given section flashes, the exansion will be far to rapid for your tubing to handle. Water will not push out the far end, instead your tubing will explode.
Please do a little more research, Allen's suggestions are very sound. I could be wrong, but it doesnt sound like you have a safe situation at all. Heating water with a high temp source is dangerous business.
Please let us know what you learn, so we can all learn together.
allen lumley wrote:Wendell K. ; Congratulations ! You have built a successful sub 6'' system with a sacrificial Lining for your Heat Riser, w/ a vertical chimney made with corrugated piping
and no horizontal chimney or thermal mass! Your build will serve to give great hope to some of our fellow members who have trouble assembling enough parts and
materials -that quite a bit of leeway is possible !
Usually we recommend that for a first Rocket Mass Heater RMH that a slightly more conventional, or traditional RMH is planned for on a first build ! We like everyone
to have success with their 1st RMH !
I would recommend finishing burning/sanding the rest of the paint off of the outside of your Barrel, before you go much farther, it is not healthy to breath that toxic
Only running Your RMH will show you when the sacrificial inner form of your Heat Riser will fail and need to be picked out. If you are lucky most, if not all of it will
come out through the Burn Tunnel and Feed Tube, without ever buckling and blocking the flow of your hot Exhaust gases ! There are a few reports of the inner steel
liner expanding and cracking the Perlite and Clay Slip Heat Riser. Many people are going to cardboard sonotubes that burn out on 1st firing, and Double thickness
Heat Riser Walls !
As the Heat riser is the most fragile part of the whole build, Be sure you have help removing and placing the barrel over the top ! For the good of the Crafts !
Think like Fire! Flow like a Gas! Don't be the Marshmallow! As always, All Questions and comments are welcome and solicited ! PYRO - Logically Big AL !