Post by matthewwalker on Oct 6, 2014 8:34:49 GMT -8
Hi guys, I'm not quite ready to post a whole lot on this topic here since I've been traveling and it's not really burning season here yet, but....
I did get started last week in the few days I had home, and wanted to share the beginning of this project. I have been pondering the conversion for a year or so, not because I thought there was an advantage or something I was missing out on, I've built plenty of batch burners and am quite familiar with them, and feel they are another great tool in a builder's kit. I'm also a big fan of the J and don't place one above the other, just different tools for different goals in a build. But, I really think there is something to be gained from living with a heater to get a perspective on how it works for an individual, lighting, fuel type/gathering, schedule, etc. Peter and I discussed the conversion of my J to a batch, and decided it was worth a try. The most important variance we were discussing is that I have an 8" J, and want to pair a batch with dimensions for a 6" system to it, since the 8" firebox is enormous, and I don't want to cut that much wood! So, the question we were discussing is how will it perform? A 6" sized box paired to an 8" riser, flue run, and chimney. We speculated on velocities through the system and such, but figured it was worth a try.
So, last week, between travels, I cut into my J and got the thing started. I've got some finish work to do still, but it's in and burning. I'll get some pics up of where it's at now, but for the moment here's the beginning of the build....
I decided to put a window on top, like we did in Montana, since that was so cool. Otherwise, it's fairly standard with the exception being I deleted the sloping firebox floor. Sorry Peter! I have a little shovel that fits the flat floor perfectly so wanted to keep it set up for easier cleaning. I've built a door, and done a few dry out runs. So far, it seems to work very well. It pretty always jumps right up to what was the max barrel temps for my 8" J, which is both awesome and kinda scary. I definitely think I won't run it stuffed full very often if ever, they just have so much power. First runs with the Testo are promising. I haven't had a run where the CO was as low as my 8" J, which ran under 10ppm typically, but the overall profile of the batch is very stable and so far efficiency is pretty high. I definitely need more heat extraction, and that's probably going to be October's project here, either lengthening my bench or adding a bell somewhere. My exhaust temps climb fairly quickly, even from cold. Anyway, here's an early run. Things were still a bit damp, so I expect it to get better in the coming weeks.
Peter, I tried to mimic your test parameters. Starting when O2 dropped by 1% and finishing when CO2 hit 4%. That last one took a while, it hung at just over 4% while the CO climbed through the coaling stage. The chart looked way better before the final 4 minutes or so. At the low point CO was down around 20ppm or so, riding usually at near 50ppm. Not bad. This was not a full load, which probably would have held stable for a longer period, but as I said, I'm a bit scared to stuff the thing as my barrel temps were high with just a half load. This was around 6 pounds of mixed hard and soft wood, at about 12% moisture content.
I did get started last week in the few days I had home, and wanted to share the beginning of this project. I have been pondering the conversion for a year or so, not because I thought there was an advantage or something I was missing out on, I've built plenty of batch burners and am quite familiar with them, and feel they are another great tool in a builder's kit. I'm also a big fan of the J and don't place one above the other, just different tools for different goals in a build. But, I really think there is something to be gained from living with a heater to get a perspective on how it works for an individual, lighting, fuel type/gathering, schedule, etc. Peter and I discussed the conversion of my J to a batch, and decided it was worth a try. The most important variance we were discussing is that I have an 8" J, and want to pair a batch with dimensions for a 6" system to it, since the 8" firebox is enormous, and I don't want to cut that much wood! So, the question we were discussing is how will it perform? A 6" sized box paired to an 8" riser, flue run, and chimney. We speculated on velocities through the system and such, but figured it was worth a try.
So, last week, between travels, I cut into my J and got the thing started. I've got some finish work to do still, but it's in and burning. I'll get some pics up of where it's at now, but for the moment here's the beginning of the build....
I decided to put a window on top, like we did in Montana, since that was so cool. Otherwise, it's fairly standard with the exception being I deleted the sloping firebox floor. Sorry Peter! I have a little shovel that fits the flat floor perfectly so wanted to keep it set up for easier cleaning. I've built a door, and done a few dry out runs. So far, it seems to work very well. It pretty always jumps right up to what was the max barrel temps for my 8" J, which is both awesome and kinda scary. I definitely think I won't run it stuffed full very often if ever, they just have so much power. First runs with the Testo are promising. I haven't had a run where the CO was as low as my 8" J, which ran under 10ppm typically, but the overall profile of the batch is very stable and so far efficiency is pretty high. I definitely need more heat extraction, and that's probably going to be October's project here, either lengthening my bench or adding a bell somewhere. My exhaust temps climb fairly quickly, even from cold. Anyway, here's an early run. Things were still a bit damp, so I expect it to get better in the coming weeks.
Peter, I tried to mimic your test parameters. Starting when O2 dropped by 1% and finishing when CO2 hit 4%. That last one took a while, it hung at just over 4% while the CO climbed through the coaling stage. The chart looked way better before the final 4 minutes or so. At the low point CO was down around 20ppm or so, riding usually at near 50ppm. Not bad. This was not a full load, which probably would have held stable for a longer period, but as I said, I'm a bit scared to stuff the thing as my barrel temps were high with just a half load. This was around 6 pounds of mixed hard and soft wood, at about 12% moisture content.
