Post by mintcake on Feb 28, 2014 14:18:48 GMT -8
Back when PeterBerg was first describing his rocket siphon, I did some computer modelling of heat flow in a bell. It showed roughly what I expected - Even with lovely hot gasses at the top of the bell, when the fire was out and you had incoming air cold, then if the entrance was pointing up then there would be quite a lot of mixing. The mixing effect was, of course, worse the higher the cold air entered the bell, and the faster the flow.
My guess is that this is part of the lower heat storage/recovery from a single bell system that Peterberg has talked about. That first bell with the heat riser going up into it isn't getting the unstirred layers we'd ideally like to see.
However, add a second bell and your ISA goes up dramatically. I've just had what might be a moment of stupidity, or might not.
Has anyone tried making a semi-single bell with a vertical partition in the upper half? Something so that only the side with the heat riser gets stirred, but the lower level gasses can mix freely. Since the partition is only in the upper half, the ISA isn't as significantly affected, and also there is less friction since there's a massive opening between the two.
Motive: I'd love to have a nice warm bench on my planned 7inch batchbox, but can't work out how to do that AND have two decent sized bells. Too much ISA.
I've got 8m of 18cm diameter uninsulated brick chimney (in the middle of the house) with quite a good draw. How worried should I actually be about over-shooting the ISA by a square meter? Oh, and how on earth do I mock up an 8m tall brick chimney outside for testing???
My guess is that this is part of the lower heat storage/recovery from a single bell system that Peterberg has talked about. That first bell with the heat riser going up into it isn't getting the unstirred layers we'd ideally like to see.
However, add a second bell and your ISA goes up dramatically. I've just had what might be a moment of stupidity, or might not.
Has anyone tried making a semi-single bell with a vertical partition in the upper half? Something so that only the side with the heat riser gets stirred, but the lower level gasses can mix freely. Since the partition is only in the upper half, the ISA isn't as significantly affected, and also there is less friction since there's a massive opening between the two.
Motive: I'd love to have a nice warm bench on my planned 7inch batchbox, but can't work out how to do that AND have two decent sized bells. Too much ISA.
I've got 8m of 18cm diameter uninsulated brick chimney (in the middle of the house) with quite a good draw. How worried should I actually be about over-shooting the ISA by a square meter? Oh, and how on earth do I mock up an 8m tall brick chimney outside for testing???