Some Questions PR vs RMH

[greezmky]

Hello all,

I found the RMHs while looking for a way to incorporate trash burning into an outdoor water heater. But that went to the wayside and I became interested in the RMH.

I then found the Pocket Rocket and built a miniature one. It worked pretty well and my simple RMH even worked good last night. the riser was not insulated and it was constructed out of bricks, but had a good draw and was quite warm out the stack (stack was straight out).

Now my idea is to heat the bottom section of a, not well insulated, barn. I cannot have a wood burning stove inside because of the insurance. So originally I was going to build a RMH with a coil inside and route the water to radiators inside the barn.

then I found the pocket rockets and found that they trow off lots of heat via the barrel, so why not shroud the barrel and pull a draft across the hot surface and pump it into the barn?

So the question is, build a box around the PR and draw the air around it. Or build a RMH and use water as heating medium?

If I draw air around the PR will it cool too much to hinder the draw and efficient burn?

Is the PR as efficient in burning as the RMH?

Sorry for all the questions but I have built some units and would like to get others opinions on my options.

Rob

[canyon]

One of the keys to efficient clean burning is high temperature and in RMH's we accomplish that by insulating in the combustion area. A pocket rocket is not insulated and radiates the heat right out from the combustion area and therefor won't be superefficient like a RMH can be. The pocket rocket really makes sense as a lightweight movable burn barrrel type heater that is much more efficient than a burn barrel. For an actual heating application like you are talking about a RMH is where it is at. You might consider piping the exhaust coming out of the heat riser (no radiant barrel) straight down around a water tank (check out donkey's cool rendition in one of the threads) or two or three in series horizontally and insulate the whole thing in. With free discarded hot water heaters it could be done cheaply. Just remember to for sure put pressure relief valves (prv) on each tank (see one of donkey's most recent posts on the subject) and have no way of isolating any piping that does not have a prv.