Post by TomS on Feb 15, 2015 21:15:48 GMT -8
First post here after lurking for the last couple of months. And now my story which I copied and pasted from my laptop....
First of all, I want to thank the folks at Rocketstove.com for freely sharing all the helpful info on how to make a good running stove. I have pored over various threads on subjects such as vortex, P-channel, proper J-tube dimensions, bells, firebrick, etc., and have gained much knowledge. I also learned from Permies.com and numerous videos on YouTube of what and what not to do.
I first tried a 40 litre grease barrel and 3 inch tubing with poor results. After that, I decided to spend a few dollars and bought 10 full-sized fire bricks. It worked much better. But, I was not satisfied, until one day a house boiler water tank showed up in the scrap metal bin, of which I salvaged. Using a grinder, I measured and cut out the feed opening and an exhaust opening. The exhaust consisted of a 5”x7” boot and a 5”x60” duct, while the stove section grew to appropriate size because more brick was bought (about 18 full sized and 2 thin ones). Several runs were made while this was outside on my garden because I wanted to do a “proof of concept” first.
After I was confident in how the rocketstove heater was running, I transferred it into my shed. A 90 degree elbow is atop the 60” section, a 24” section going through the wall is plugged into the elbow on one end and a TEE on the other, finalized and topped by a 30” duct pipe. The stove ran great in this configuration, and drafts quite well. While burning plywood scraps I could only attain 200°C., which was okay since I was “cleaning up”. I have switched to pallet slats which are ripped to about 1 1/2” wide, and have reached much better numbers. I can now get over 320°C (my IR meter reads “EER” passed tahat point) and keep it sustained at that point if the fire box is kept full. At those times, the exhaust temp at the outside TEE peaks at 51°C.
I have started the stove when the in-shed temp was at -5°C numerous times, but it needs a bit of nudging with the propane torch. Recently, it was -20°C with 40-60 Km/h (25-35 mph) and I was getting back draft, sometimed with flames jumping back out by 25cm (10”). Adding another 30” duct, for a total of 60” atop the TEE, got the exhaust away from the roof a bit more and reduced back draft significantly. During those conditions, I was insulating the shed to R14 on 3 walls, R22 on one wall and the ceiling, and managed to get the shed up to +18°C inside. The shed size is 12'x28' on the outside with a gambrel roof. I am very thankful because I have reached my goal under what I would consider adverse conditions.
Before I started any and all of this, I had never owned or operated a woodstove.
As a side note: normally there is a box fan blowing across/above the tank/bell, and I can't hear the fire going. Also, I typically listen to music. However, a couple of days before I added the second section above the TEE, I had not turned on the fan or the music. I was removing nails from the pallet slats, listening to the rocketstove, and all of a sudden!.....I heard it! It was pulsing!!! just like PeterBerg posted! It lasted for about 10 seconds.
First of all, I want to thank the folks at Rocketstove.com for freely sharing all the helpful info on how to make a good running stove. I have pored over various threads on subjects such as vortex, P-channel, proper J-tube dimensions, bells, firebrick, etc., and have gained much knowledge. I also learned from Permies.com and numerous videos on YouTube of what and what not to do.
I first tried a 40 litre grease barrel and 3 inch tubing with poor results. After that, I decided to spend a few dollars and bought 10 full-sized fire bricks. It worked much better. But, I was not satisfied, until one day a house boiler water tank showed up in the scrap metal bin, of which I salvaged. Using a grinder, I measured and cut out the feed opening and an exhaust opening. The exhaust consisted of a 5”x7” boot and a 5”x60” duct, while the stove section grew to appropriate size because more brick was bought (about 18 full sized and 2 thin ones). Several runs were made while this was outside on my garden because I wanted to do a “proof of concept” first.
After I was confident in how the rocketstove heater was running, I transferred it into my shed. A 90 degree elbow is atop the 60” section, a 24” section going through the wall is plugged into the elbow on one end and a TEE on the other, finalized and topped by a 30” duct pipe. The stove ran great in this configuration, and drafts quite well. While burning plywood scraps I could only attain 200°C., which was okay since I was “cleaning up”. I have switched to pallet slats which are ripped to about 1 1/2” wide, and have reached much better numbers. I can now get over 320°C (my IR meter reads “EER” passed tahat point) and keep it sustained at that point if the fire box is kept full. At those times, the exhaust temp at the outside TEE peaks at 51°C.
I have started the stove when the in-shed temp was at -5°C numerous times, but it needs a bit of nudging with the propane torch. Recently, it was -20°C with 40-60 Km/h (25-35 mph) and I was getting back draft, sometimed with flames jumping back out by 25cm (10”). Adding another 30” duct, for a total of 60” atop the TEE, got the exhaust away from the roof a bit more and reduced back draft significantly. During those conditions, I was insulating the shed to R14 on 3 walls, R22 on one wall and the ceiling, and managed to get the shed up to +18°C inside. The shed size is 12'x28' on the outside with a gambrel roof. I am very thankful because I have reached my goal under what I would consider adverse conditions.
Before I started any and all of this, I had never owned or operated a woodstove.
As a side note: normally there is a box fan blowing across/above the tank/bell, and I can't hear the fire going. Also, I typically listen to music. However, a couple of days before I added the second section above the TEE, I had not turned on the fan or the music. I was removing nails from the pallet slats, listening to the rocketstove, and all of a sudden!.....I heard it! It was pulsing!!! just like PeterBerg posted! It lasted for about 10 seconds.