The objective with most biomass boilers is for them to run automatically, drawing fuel as needed from a storage area. In the early design stages it is important to establish where in relation to the boiler the fuel store can be sited, bearing in mind the initial fuel delivery to the store. In order to prevent "bridging" of the fuel the base of wood chip stores need an agitator. There are several options for this:
The spring feeder (two rotating spring loaded arms that drag the fuel towards the extract auger) is suitable for small and medium sized fuel stores and where the wood chip fuel is G50 size or below.
Heating power range: 60 - 1100 kW
Fuel capabilities: Pellets, wood chips (max W40)
Rural Energy has a range of commercial boiler products well suited to larger heating applications. The Herz and Endress boilers are the result of decades of development in Austria and Germany, all are certified to the latest standards on efficiency & emissions have been fully proven in the UK with over 250 installations to date.
The scrapers are the hydraulic 'walking floor’ system is also available and is more appropriate where fuel store capacity is in excess of 150 cubic metres or the wood chip fuel to be used has moisture content approaching 50%.
The excellent flow characteristics of wood pellets allow a range of flexible and rigid auger systems. These can be configured either horizontally or inclined to achieve the transport distances required. Pellet augers tend to be a lighter construction than chip augers and as such are restricted to pellet fuels. Therefore if it is intended to change fuel type during the life of the installation, the fuel feed must be built to handle wood chip even if initially used for pellets.
The "Fuel Reception Area" is the location where the fuel is unloaded from the delivery vehicle. Of primary concern for wood chip is that the vehicle can tip, preferably directly into an underground storage chamber. Design considerations include vehicle turning circles, head room for the tipping trailer, bunker lid type (lift or slide) and appearance.
Alternatives are for delivery hoppers to remain outside with auger elevators to carry the fuel up and to a the store. Rural Energy have experience of many different options and as part of our design assessment we would recommend the most appropriate configuration based on your needs and preferences.