Quick Answer
A well-designed rocket mass heater (RMH) typically consumes about 2-5 pounds of dry cordwood per hour, depending on the size of the heater and the desired temperature output.
Fuel Efficiency and Sizing
A rocket mass heater is an efficient, high-temperature heat source that uses a carefully designed combustion chamber to convert small amounts of fuel into a high-temperature flue gas. To determine the correct size and fuel consumption for a specific RMH, you need to consider factors such as the desired temperature output, the size of the combustion chamber, and the type and moisture content of the fuel being used. A general rule of thumb is to start with a smaller combustion chamber size (around 6-8 cubic feet) and adjust as needed to achieve the desired temperature output.
Calculating Fuel Consumption
To calculate the fuel consumption of an RMH, you need to consider the following factors: the moisture content of the fuel, the size and type of the fuel, and the desired temperature output. A dry cordwood fuel with an 18% moisture content will generally produce more heat than a wet cordwood fuel with a 40% moisture content. For example, a 2-inch diameter log with a 6-foot length will produce approximately 3,500-4,000 BTUs of heat when burned in an RMH. Based on this calculation, a 2-3 cubic foot RMH will consume around 2-4 pounds of dry cordwood per hour to maintain a temperature output of 500-800°F.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.