Installation Layout Options

My general plan is to install an RMH in a (6m x 4m) sunroom that opens up to the rest of the house through 2 large doorways.
If convection becomes an issue I will install 2 small low speed convection fans on the ceiling.

My question is whether or not I could effectively place the burn unit/barrel outside the sunroom (in a small insulated shed directly adjoining the sunroom) and tunnel the manifold cob thru the wall (into our sunroom).
The key advantage of this would be to keep the flame centre outside of the living area.

I think so long as there are no cold joints in the installation, then it should be fine wrt heat loss.
I am curious whether others have the same feeling about this .. or even better, some experience with this or a similar approach.

Secondly, it occurred to me that a significant portion of the heat radiated may actually come directly from the burn chamber barrels during the burn (i.e not the heat that is radiated via the cob/manifold). If that's true (maybe somebody has some % stats or something), then my floorplan could could result in valuable heat loss. Any thoughts on that ?

Many Thanks

I dont think that is a good idea, the barrel will radiate huge amounts of heat especially considering the small fire but the mass will only offer a gentle low heat.
So every time you have to feed your fire (every 15 minis if a J tube model) you will enter a shed that is absolutely boiling hot, like 200 f or more!
The whole concept is to quickly heat your space with radiant heat from the barrel and then store some of the excess heat into a slow release mass.
Not everybody would want an old oil drum in there living space but perhaps you could investigate other styles of rocket mass heaters that seem to be becoming ever more popular.
Look for batch box designs and particularly look for mass heaters that use a bell  rather than a bench.
This type of heater can look really nice in any house and only needs loading only every one to two hours.

Fox James wrote:The whole concept is to quickly heat your space with radiant heat from the barrel and then store some of the excess heat into a slow release mass.

So, that is really the answer to my fundamental question about what fraction of the heat emanates from the barrel.
Clearly it is a significant amount, and this makes sense.
So, the barrel operates in this sense as a regular fireplace but yields significantly hotter temperatures.
And, for the manifold, we exhaust the somewhat cooled air via our cob assembly and store what our cob is capable of storing.
All good.

So, I still would like to have the barrel and flame outside the room.
Have people maybe 'manifolded' the barrel so that the air passing over it is vented like a vector into a duct which is also then piped into the target space/room ?
I think such an idea might work.