These systems are usually more suited to larger projects, or where a local source of chip is available as the fuel type. Handling and delivery systems are usually external to the boiler and invariably require additional space for large fuel stores due to the low calorific value of the fuel. Wood chip does not flow like pellets so most installations need the fuel delivered directly from the truck, either by tipping into a subterranean store or using a hook bin systems. However, all wood chip boilers will have an automated system for the fuel delivery from the store into the boiler. It is very important with a chip boiler is that the fuel meets the specification of the boiler and delivery systems. All this makes them more suitable for rural locations or larger sites.
Wood chip’s biggest advantage is the cost of the fuel; with prices at about 3p/kWh it offers significant savings compared with oil and LPG fuel. Due to the bulk of the fuel a local supplier is always sourced before the boiler is installed. We have had many customers with managed woodlands who install wood chip boilers and benefit from this lower fuel costs.
Several fuel handling mechanisms are available including sweep arm tables and moving floors. Wood chip boilers are highly dependent on the fuel’s characteristics, which means the boiler must be supplied with fuel of the appropriate moisture content and particle size. A hopper containing 5m³ of wood chips will provide 5-15 days of running for a farmhouse sized unit if the chips are fairly dry (25% moisture content). A careful estimate must be made of the heating load of a particular site and the hopper is then sized to reflect the lifestyle requirements of the site owners or the building services available at larger commercial sites.
Recent experiments have shown that boilers that burnt wood chip with a higher moisture content than they are set up to receive causes problems with smoke and poor burning due to the formations of acids within the flue and boiler, leading to the premature aging of the system.
For the range of chip boiler please click here
Very cheap fuel
Low running costs
System can modulate output of the boiler
Fuel needs to be delivered to fuel store
Good quality chip required to avoid boiler problems
Careful design of fuel store to avoid costly delivery