sending exhaust out the wall vs. the roof

ole,
it might look like that your horizontal run is a bit too long? what s the lenght?

have you tried feeding smaller sticks that totally fit inside feed tube?

my general thoughts on vertical exhaust are that these systems are very volatile. you change one parameter a bit and that whole thing might backfire. in your case, ole, it looks like several parameters are working against you in this case. when these add up, things go wrong.



ok, this is a abit far out... exhaust temperatures should be very low. what about building a chimney from wood? just wondering ...
( i m feeling like highjacking this thread, so if anybody sees the need to move parts of this discussion...)

"a 5 meter high dobble insulated steel chimney, as would be required here"

Do you mean that building code would require such a chimney, or that you think that is what would be needed? While I'm sure a chimney that big would be good, it may not be necessary. Even a single-wall 2 meter chimney might be enough for your system to work. I would try some more experiments to see what does it. The exhaust is going to be cool enough that you can probably paint the chimney with some camouflage to make it practically disappear.

Tobias: Length of the horizontal run is about 27 feet.
I tend to agree with you, too much is against this construction.
Exittube is about 30 degree celcius with outside temp at zero.
You are not hijacking anything, Im very happy for all contributions!

Glenn: Yes, because of the two storage building, the chimney must be 5 meter high, and dobble insutaled is a must. So there are good reasons to find other solulions

Ianto, ok, I think I get it now. Next time I try, I will make a 6 feet riser and a biiiiiiig voluminous bell.

Exhaust about 30 C... that's barely warm. Why would you need a double insulated chimney? I suppose that would keep the exhaust from getting too cold...

Yes, you are right Glenn. The insulated chimney would help.
Allthough it is purely mafiosic regulations ;-(
But you know, with a regular chimney fire you would like to have it over the houseroof.

Well, I got very inspired by this idea some years ago. This autumn I wanted to realize the idea. Now, 4 rebuilds later, I can conclude with a simple answer: The riser is by far high enough to create the needed draft. With a simple bathroom ventilator, drawing 90 m3/hour everything works just fine. And I suspect all my previous builds might have worked just as fine this this kind of draft.

I am going to bring this thread back up.  Is it possible to vent out a window if a fan is used.  I want to replace the propane heater in the living room with a rocket stove.  I don' t know if I have the skills to make a chimney.  Thanks!

Hi Jane,   For the first year with my rocket mass heater in my shop, I went out the window without any fan. After gaining confidence, the second year I went through the wall.  I also brought it up past the peak of the pole barn by about 2 feet to eliminate any problems with wind backdrafting down the pipe. All pipe outside was insulated to keep condensation from forming and also to help keep the exhaust warm enough for proper draft.
I live out in the boonies so there is no problems with neighbours, codes or insurance issues to hinder my experiments but leave it up to you to look into that for your own situation.

Thanks Gerry  No one can see us either.  Lots of trees and fairly remote.