Jasmine Maurer wrote:We installed two benches, but on two different floors maintaining air flow in one direction.
Manifold is a general misnomer in this case, and I think is confusing to many in this regard, but it is simple to figure out why this term was used and there is no reason for not having a manifold, if your system is designed for it. It is called a manifold (and could potentially be), but should be called a unifold since that is how it has been built in most RMH systems. The term manifold as it is being used here, comes from idea of the space of the unit where the gasses are exiting the combustion/thermo-siphon area, and are exhausting into the flue/bench/mass area, like when exhaust exits many engines in a true manifold.
It IS called a manifold
From what I have learned, it is best to have the outlets 4 inches or so above the floor of the manifold/burn area. This allows a place for ash to settle (and be cleaned out) and not go into your bench pipes. You could have two over each other, above that 4 inch height, but it might be better to have them side by side or on opposite sides.
Also, what if the two outlets are at different heights? One directly under the barrel, and one about 8 inches lower?
Restriction = friction, and that is not what you want. You want flow, and heat absorption in your mass, as much as possible. As I've had it explained by Peter V Berg, a chimney next to the barrel does heat up the pipe and thus increase flow, but it also results in heat loss from your efficiency since it is absorbing radiant heat from your barrel and allowing that absorbed heat to flow out of your home, as well as increasing the velocity of that which is lost from your mass up your chimney with the increased velocity. Thus, from the way I see it, it creates several points of inefficiency.
when it comes to airflow in ducts, simple really is better. Each bend, split, or junction imposes a measurable restriction on flow diminishing the benefit of the reheating.
Chad Sentman wrote:I'm building what's basically going to be my first COMPLETE RMH build
I'm building my first completed/second started RMH at the moment.