The Derrick build uses an 8" Dragon Heater core with 55 gallon steel barrels to create a high efficiency, quickly built wood-fired masonry heater. These heaters are idea for locations where looks are not a criteria, but long periods of heat release without tending a fire are required. Its small footprint and quick assembly/disassembly make it a perfect option for locations where temporary heating is required. The barrels are filled with fireclay bricks, loosely stacked.
The shorter column of barrels is used to house the combustion system and the 2nd taller column is used for thermal mass heat storage. Exhaust is moved from the combustion tower to the thermal mass heat storage barrel tower via a special cast refractory collar and joining gaskets. As the exhaust gases lose their heat to the thermal mass, they drop to the bottom of this tower and are swept out to the chimney.
This is wood fired heater is perfect for greenhouses, barns and shops. The ability to store and release heat overnight is perfect match for a greenhouse heater. Low surface temperatures also make it a good choice for a barn heater. The high efficiency combustions system combined with high thermal mass for heat storage provides a new option for heating.
The Derrick design stores most of its heat in thermal mass for gradual release. In contrast, a traditional rocket mass heater releases most of its heat (as much as 2/3rds) immediately to the surrounding space via its radiating barrel. In addition, the Derrick Build has a smaller footprint allowing room for multiple heaters, which are usually required in cold winter climates. They are quicker to build and can be easily removed at the end of the season and stored elsewhere during the off-season.
Even paying $200/cord for wood, the BTU's from a Dragon Heater cost one third the price of propane or electricity. Depending on your annual fuel consumption you can easily pay for your Derrick Build in one season. In addition, since they use no electricity and require no processing of the fuel (other than splitting), they offer the ultimate in reliability.
The wires are probes used to monitor heat storage and release. This is a 2.5 drum thermal mass storage tower located in an aquaponics greenhouse.
The amount of heat stored is based the rate and length of time the heater was run, as well as the size and configuration of the thermal mass. The taller tower which houses the thermal mass can be either 2, 2.5 or 3 barrels high. If using less than 3 barrels, the bottom barrel can include openings in the bricks to allow heat to directly radiate at the lower level to remove excess heat.