There seems to be a question about where the stack should go.... Below is a house.... consider it a smoker.... In the explanation, the location of the inlet to the chimney is not considered in the calculation... the primary factors in calculating chimney draw are... the air inlet height... and the chimney exhaust height.... (h) ....... and the air density... the other factors are friction and friction loss in a moving stream of air...elbows... etc....
So.... in conclusion.... I don't know what parameters Alien used when developing the calculator and have stated such in other threads... I assumed Alien used the difference in height from the inlet air and stack height to make the calculator... (Alien is one smart dude) and used a theoretical average to simplify stuff for the masses....
He obviously chose some good averages as his calculator works very well.... That being said, I assumed Alien meant the height above the Cook Chamber for stack height value in the calculator... and that is where I base my conclusions....
From the drawing, the length of the chimney does not enter the calculation in any part....(except for friction and friction loss)
The chimney could be put on the roof peak.... and be 24" tall......
Turn4Fun..... "
[color= rgb(24, 24, 24)]Wait, has something changed with pit design in the last couple of years?"[/color]
Edited by Dave
I needed a starting point to help folks build their smokers and this is what I chose... I can reference back to it and explain my calculations based on Aliens calculations... When I get "general consensus"... I try to prove which ideas make the most sense to me, based on some sort of proven theory.... I could be totally wrong on the way I interpret Aliens models... either way... not a big deal... Seems Alien left enough leeway for the smokers to work well regardless of how you interpret his numbers....
Your smoker working very well is a testimony to the mans genius....
Because we both chose a different path to interpretation does not infer one of us is in error... I could not find any "hard and fast" rules for the calculator....
Edited by Dave:
In the drawing above.... the chimney could start in the basement and would still need to be the height determined by (h)....
So.... you could have a 20' chimney or a 6' chimney.... as long as (h) was satisfied in the equation....
[h3]Natural Draft Head[/h3]
The natural draft is caused by the difference in outside and inside air density. The natural draft head can therefore be expressed as
dp[sub]mmH2O[/sub] = (ρ[sub]o[/sub] - ρ[sub]r[/sub]) h (1)
where
dp[sub]mmH2O[/sub] = head in millimeter water column (mm H[sub]2[/sub]O)
ρ[sub]o[/sub] = density outside air (kg/m[sup]3[/sup])
ρ[sub]r[/sub] = density inside air (kg/m[sup]3[/sup])
h = height between outlet and inlet air (m)
