Wood stove heat reclaiming unit

[Frank S]

I hate my computer these days.
I started to create a reply and the keyboard jumped then wiped out everything I had typed.
So I will create one in word then copy paste and see if that works better.
Any way the heat recovery unit worked well except for a couple of issues which I will address when I build a stove for my workshop and install it there.
I found that I had to maintain a very hot fire in the stove in order to prevent coking or creosote buildup. I used the cleanout disk several times but found that it was a lot of trouble eventually I had to use a slide hammer just to get it to move back and forth so I removed the unit. I wish now that I had flattened the tubes to an oval which would have meant the exhaust gases would have a higher velocity and would have remained hotter until reaching the chimney. There is a fine line between the amount of thermal recovery and maintaining a high enough exit velocity to insure proper combustion has occurred. Different wood has varying amounts of creosote in the unburned exhaust. The introduction of forced air at the fresh air intake would reduce the criticality of maintaining a hot exhaust to insure proper combustion and a complete reduction of materials to ash without creating the creosote residue in the chimney.
After removing the unit, leaving the original straight stack to preserve heat I stacked 250 lbs. of 6 inch ceramic tiles on top of the stove, creating a thermal mass for heat storage. In doing this I found that I could build a medium to large fire of an evening with a small 8 inch fan behind the stove on the mantle and the ceiling fan on low with outside temps falling into the low 20’s or even down to single digits re stoke it once around midnight to keep the front half of the house comfortable so I blocked off the back half since we are only using the back 3 bed rooms for storage anyway I also burned through less than half the amount of wood we were previously using
So there you have an update to the heat recovery unit at its present design there needs to be forced fresh air to create higher combustion temperatures or the tubes need to be oval possibly a combination of both

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Thank you Frank S for sharing this, it looks wonderful. you seam to have a good head for this.
Ed