Glenn Herbert wrote:Cross posting... Good for insulating under the RMH. Making an actual air separation so air can carry heat from all sides of the mass to the interior would be best, but insulation is good. Aluminum foil is effective as a radiant barrier, but that only works when exposed to an air layer. Touching other material, it does absolutely nothing.
I'm curious what prevents you from exiting the roof at the peak with your chimney. You will need to go to the same height wherever you locate it, and anywhere else makes more pipe exposed to the cold exterior, and needing to be supported against wind.
Glenn Herbert wrote:By code, the chimney is supposed to be at least 2' higher than any roof/structure within 10' and at least 3' above the point of exit. This is not just bureaucratic mumbo-jumbo, there are good reasons for it. With the pointed dome, you could probably be safe with a bit less than the 2' rule as it will not generate the kind of turbulence and downdrafts that a gable would. You would need to make the chimney secure against wind, which means either making it very strong and connected to the dome structure, or braced to the roof above.
I doubt you need to have the fan so high that there could be no space next to it for the stovepipe. A small ceiling fan should work fine for a space the size of your dome. I would hang the fan with 8" to a foot of clearance from the dome sides, or possibly slightly off center, and run the stovepipe up to near the top. Exiting there would give a less obtrusive look overall.
If heat in the summer is a serious concern, I might make a removable section of stovepipe so hot air could escape the top of the dome.
Gerry Parent wrote:Sonny, Glenn's comments about the chimney exit are all tried and true methods which would provide the most trouble free installation however, as your building is round and streamlined to the wind, perhaps downdraft may not be an issue for you? There are so many factors that make for a good draft. You could skimp on a few and still be OK but best to not make them unless you really want to accept the possible consequences (aka have a backup plan).
Sorry I couldn't add any assurance for you, but perhaps someone else may have more experience with a structure like yours.
Aaron Tusmith wrote:Sonny your building is so cool, would fit right in on Tatooine
Daniel Ray wrote:Wow, great build. Love Calearth and what they do to teach.
I'm going to reiterate Thomas and mention the importance of insulating under the burn chamber. My first build was similar and it eventually burnt away the cement beneath the burn chamber.
Dillon, i think you were referring to Thomas' mention of the stratification chamber rather than the double barrel initial bell technique show in my photo. Thomas prefers using bricks for the transition area.
The half barrel stratification method is using barrels cut in half lengthwise and used for the second bell of the system as demonstrated here http://donkey32.proboards.com/thread/716
Sonny, if you do stick with the piped bench, remember to calculate the total distance with +5 feet for every 90 turn. If you use a lot of elbows you'll need to figure how many 90s you end up doing before the chimney which looks like it will be in a good spot near the barrel. You should clear the top of the structure by several feet.
If you are unsure about cutting your bricks for the octagon riser, you could do a square riser with corner pieces for the first half of the riser which is successful at giving my stove the "rams horns effect". I've included another photo of this.
Good luck! and post some photos.