Does anyone have any experience using very high BTU rated wood in an RMH? I have seen conventional stoves burnt out rather quickly when fired hard with eucalyptus. Around here I can have all of the eucalyptus I want for free, as it is an invasive specie. Any thoughts about special design considerations? Thank you
I burn a fair bit of eucalyptus and Tasmanian blackwood (a dense acacia with even more heat value) in my little J-tube RMH. They work great. The nice thing about a rocket system is that the entire combustion path is designed for high temperature, so it is well suited to hot fuels.
Hi Jennifer: Welcome to Permies!
There is nothing you can burn that is to hot for an RMH. Back east, folks who have access will put anthracite coal in to burn.
Black locust, eucalyptus, orange osage, or any hard or soft wood a Rocket mass heater will happily burn them as long and hot as you can stand it.
As far as design modifications; Any proven rmh build style will work fine. If you have the finances then using the newest product innovations, like ceramic fiber blanket for a 5 minute riser and ceramic boards for your core will give you more heat sooner than a old school heavy firebrick core. But A heavy firebrick core will work just fine for many many years.
Do you have a copy of the RMH builders guide ? Highly recommended! Easily available on Amazon.
I just want to make sure you know that a proper rocket stove doesn't use metal in its core as it WILL burn out at the temperatures it will reach. Basically, if metal doesn't burn out, it's not burning at the temperature which defines it as a rocket stove.
Eucalyptus is also an invasive around here. It is not used much as fire wood mostly because it 'pops' frequently and explosively. Think burning embers being flung across the room every few minutes. If you choose to burn it make sure you have an appropriate screen to prevent embers from burning down the house.
We use it mostly for structural timber as it is very hard although difficult to work.