Quick Answer
Yes, outdoor wood boilers can be used for heating water, but it requires careful consideration of the system design and components due to the unique demands of water heating.
Design Considerations for Water Heating
When using an outdoor wood boiler for water heating, it’s essential to choose a boiler specifically designed for hydronic heating systems, which typically have a higher boiler efficiency and a built-in circulation pump. A minimum of 1,000 gallons of storage capacity is recommended to maintain heat in the system and to allow for a stable water temperature. Additionally, a mixing valve is required to regulate the temperature of the water being distributed to the water heater.
System Components for Water Heating
The system will require a water heater or heat exchanger, a buffer tank, and a mixing valve. A plate heat exchanger or a shell-and-tube heat exchanger can be used to transfer heat from the boiler to the water. It’s also crucial to consider the flow rate through the heat exchanger, typically 10-20 GPM, to ensure efficient heat transfer. A minimum of 12 kW of heat output is recommended for a domestic water heater system.
System Sizing and Efficiency
The system should be sized based on the heat load of the water heater, the size of the storage tank, and the efficiency of the boiler and heat exchanger. A well-designed system can achieve an efficiency of 70-80% or higher. It’s also essential to consider the emissions and air quality regulations in your area, as outdoor wood boilers can be subject to specific requirements. A competent installer or system designer should be consulted to ensure the system meets all local regulations and is properly sized and configured.
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