Merch store here: https://suburbanbiology.creator-spring.comTHE BOOK I USED: "The Rocket Mass Heater Builder's Guide: Complete Step-by-Step Construction, Mai...
The goal is to have the fire drive a high airflow, both to give itself oxygen, and to pass the exhaust through a long path of heat absorbing dirt. The metal drum does this by passing the hot exhaust up through its center, then rapidly cooling it as it falls back down along the metal surface. The difference in density drives the airflow. The drum needs a high thermal conductivity to be able to maintain this temperature and density difference, and this is also the primary way the heat is transferred to the living area. The earthen part gathers up the remaining heat to increase efficiency and retain heat for when the stove is off, but most of the heating is done immediately through the metal.
The goal is to have the fire drive a high airflow, both to give itself oxygen, and to pass the exhaust through a long path of heat absorbing dirt. The metal drum does this by passing the hot exhaust up through its center, then rapidly cooling it as it falls back down along the metal surface. The difference in density drives the airflow. The drum needs a high thermal conductivity to be able to maintain this temperature and density difference, and this is also the primary way the heat is transferred to the living area. The earthen part gathers up the remaining heat to increase efficiency and retain heat for when the stove is off, but most of the heating is done immediately through the metal.