Post by mwalimu on Dec 26, 2014 23:10:54 GMT -8
Hi there again after some while!
My RMH is ready, but still missing some mass. Means the bench is not yet ready, but the pipes are there. I made a lot of experiments to get all the heat out of the exhaust gasses, but not everything worked fine. This I will report separately.
The RMH actually is working fine. It is a 8" system with J-Tube. Here are the specifications:
- Combustion unit is built on a 3 cm thick plate of soft fire brick.
- Feeder: square 6x6", 1 1/2' high.
- Burning chamber: With a kind of venturi, 5" wide, 9" high, made out of 3 cm thick soft fire brick, quite short.
- Secondary air: Two vertical slots 1 cm wide left and right of the venturi at the begin of the burning chamber, sucking pre-heated air from the feeder.
- Riser: Base is made hexagonal out of soft fire brick 10" high, a bit narrower than the riser, so a trim is surrounding the base of the riser pipe.
- Riser is a High-Temp ceramic hard pipe with inside diameter 20 cm / 7.8" 140 cm high on top of the base. It is only 2cm (4/5") thick and no insulation around.
- Drum: There is a 200 liter barrel (58 cm by 80 cm) with the bottom 40 cm over the top of the riser pipe. So the complete Structure is 2 meter high.
- Below the drum there is a rectangular bell out of medium burnt bricks, wider than the drum with lot of space for the exhaust gasses to sink down.
So the heat exchanger / downdraft part is actually a bell, consisting out of a metal drum for quick heat exchange on top and a brick base below for heat storage.
-The base of the bell is connected to a 4.5 meter long pipe of 15 cm (<6") stove pipe, with a 2 m high vertical 12 cm (4.5") pipe as chimney / stack / exhaust. I had nothing else at hand.
Performance:
- Starts easily from cold with very few balls of paper and sticks and without smoke.
- fire catches quickly bigger fuel wood, making the typical noise.
- The drum gets hot within few minutes, very even heat distribution.
- The bell below needs two hours or more to get warm.
- The exhaust stays cold very long, at the end of a heating session you still can touch it (it will be less after a mass is added)
- The exhaust is releasing white steam. Period. Like the smoke out of a modern gas or oil furnace.
- The smoke/steam has a bit of woody smell, but not inconvenient like normal wood fire smoke.
- I fire the stove 3-4 hours a day. I'm not yet living in the flat, but use it as a workshop.
- The 3 rooms with door open get warm within one hour.
- There is a massive 5" brick wall to the kitchen near to the drum. It heats up as well and keeps the kitchen warm to a certain extend.
- Upstairs - above a wooden ceiling - under the roof are two small rooms, which are getting warm as well.
- The ground floor below is not getting really warm, but the pipes are kept from freezing.
Okay, not yet perfect.
It seems if I switch to larger pipes, I can add length as well. I think about 10 meters (33').
Donkey: No images. New smartphone broken. F***!
My RMH is ready, but still missing some mass. Means the bench is not yet ready, but the pipes are there. I made a lot of experiments to get all the heat out of the exhaust gasses, but not everything worked fine. This I will report separately.
The RMH actually is working fine. It is a 8" system with J-Tube. Here are the specifications:
- Combustion unit is built on a 3 cm thick plate of soft fire brick.
- Feeder: square 6x6", 1 1/2' high.
- Burning chamber: With a kind of venturi, 5" wide, 9" high, made out of 3 cm thick soft fire brick, quite short.
- Secondary air: Two vertical slots 1 cm wide left and right of the venturi at the begin of the burning chamber, sucking pre-heated air from the feeder.
- Riser: Base is made hexagonal out of soft fire brick 10" high, a bit narrower than the riser, so a trim is surrounding the base of the riser pipe.
- Riser is a High-Temp ceramic hard pipe with inside diameter 20 cm / 7.8" 140 cm high on top of the base. It is only 2cm (4/5") thick and no insulation around.
- Drum: There is a 200 liter barrel (58 cm by 80 cm) with the bottom 40 cm over the top of the riser pipe. So the complete Structure is 2 meter high.
- Below the drum there is a rectangular bell out of medium burnt bricks, wider than the drum with lot of space for the exhaust gasses to sink down.
So the heat exchanger / downdraft part is actually a bell, consisting out of a metal drum for quick heat exchange on top and a brick base below for heat storage.
-The base of the bell is connected to a 4.5 meter long pipe of 15 cm (<6") stove pipe, with a 2 m high vertical 12 cm (4.5") pipe as chimney / stack / exhaust. I had nothing else at hand.
Performance:
- Starts easily from cold with very few balls of paper and sticks and without smoke.
- fire catches quickly bigger fuel wood, making the typical noise.
- The drum gets hot within few minutes, very even heat distribution.
- The bell below needs two hours or more to get warm.
- The exhaust stays cold very long, at the end of a heating session you still can touch it (it will be less after a mass is added)
- The exhaust is releasing white steam. Period. Like the smoke out of a modern gas or oil furnace.
- The smoke/steam has a bit of woody smell, but not inconvenient like normal wood fire smoke.
- I fire the stove 3-4 hours a day. I'm not yet living in the flat, but use it as a workshop.
- The 3 rooms with door open get warm within one hour.
- There is a massive 5" brick wall to the kitchen near to the drum. It heats up as well and keeps the kitchen warm to a certain extend.
- Upstairs - above a wooden ceiling - under the roof are two small rooms, which are getting warm as well.
- The ground floor below is not getting really warm, but the pipes are kept from freezing.
Okay, not yet perfect.
It seems if I switch to larger pipes, I can add length as well. I think about 10 meters (33').
Donkey: No images. New smartphone broken. F***!