We have been working on some fun Rocket Heater projects. You might have seen the 8″ with a big cob bench that heats our 1600 sq. ft. uninsulated barn apartment even though our renter managed to blow the cleanout caps and crack the barrel seal by trying to start it with gasoline — I think it would have killed him if it had been a regular woodstove. I had been told that an autoclaved concrete core would disintegrate but its holding up pretty well in year two.
Or the big need in Ohio for a cost-effective way to heat a greenhouse. An 8″ dragon core would do the job better but this portable 6″ was designed and built in about 4 hours and works very nicely using off-the-shelf parts including flanges from a Tractor Supply barrel stove kit. I will be trying a double bell tower on it in a couple days.
The most fun lately has been designing and building a system to heat a 40′ school bus around a 4″ dragon core http://www.dragonheaters.com/?a_aid=industrialrustic. The cast refractory core sits in the bottom third of a 50-gallon drum with an inverted 30-gallon drum and its lid housing the riser. The double 30-gallon drum bell never got above about 85 degrees in 30-degree weather so we adjusted it to be a single 30-gallon bench bell that feels quite nice to sit on within a few minutes of lighting the first match. We will have to figure out a drain for the condensation in the heat riser drum and bell drum. Once Jacob gets some insulation in that bus there may be some heat left over for storage but right now it’s all going for instant heat.
–Chris “Uncle Mud” McClellan