Wood Heating Systems
The choice of which wood heating system you choose will depend on whether you have your own source of a certain type of fuel, the size of the space you wish to heat, how automated you need the system to be, how much room you have for the burning equipment and the fuel storage and how fuels will be delivered to site.
Pellet boilers are appropriate for a range of applications, from domestic to community projects. They automatically ignite, feed fuel, self-clean and switch off when not required. They range from around 15kW to 1MW. Pellets for larger installations are delivered by tanker and blown into the storage room or silo. It is important that storage facilities stay dry and remain sealed to prevent dust from entering the boiler room.
As the use of pellets is increasing, the UK Pellet Council have created a guide to pellet storage and handling using over 20 years of wood pellet experience from Germany. The guide covers maximum distances from storage hopper to delivery truck, bends in pipework, auger styles, moisture ingress and coupling types.
This FREE guide can be downloaded from:
The UK Pellet Council Website - Pellet Storage and Handling Guide
Case study – Bleddfa Centre
Case study – Mr Bennet, Carmarthenshire
Pellet stoves (2kW – 15kW) are easily installed, ideal as one room heaters, and come in many designs. They ignite automatically and operate with a high level of control, often remotely. Pellets are easily loaded into integrated hoppers, have long periods between re-fuelling and flow automatically into the burner. Stoves will need an electrical supply but require little cleaning out. Models are also available that combine room heating with hot water and central heating capabilities.
Wood chip boilers are commonly designed to operate with a particular specification of fuel. Consistent chip size and moisture content is important for boiler feed mechanisms. Specialised chippers designed to produce chip of a consistent enough specification for boiler use are available through professional contract mobile chipper services. Tipping from a lorry into an underground bunker is the most efficient way for your client to have wood chip delivered. Above ground storage structures need to fit well with the capability of the delivery vehicle to tip wood chip over the storage retaining wall. Where wood is being chipped on site, chip can be blown easily into above ground bunkers, thus saving on construction costs. Other practical delivery mechanisms include fast fill auger systems, replaceable hook lift fuel containers and drive in walking floors. It is common practice for large boiler installations to also incorporate an auxiliary fossil fuel boiler so that during prolonged poor weather conditions, when delivery may be difficult, buildings can still be heated.
Case study - Penmorfa
Log boilers, suitable for large domestic and small commercial settings, are available from 15-80kW, from basic boilers, to sophisticated, fully controllable domestic heating and hot water boilers that can work at efficiencies above 90%. These boilers are easy to load and ignite, and are often housed in adjoining outbuildings. They are batch-fed (usually once a day), storing the heat in an accumulator tank for use on demand. When choosing a log boiler the size of the fuel chamber dictates how much energy can be provided from a single charge. The boiler and accumulator will take up a considerable amount of room. Logs are heavy and awkward to transport from storage to boiler, therefore it is important to plan enough storage space close to the boiler and to be sure that the operator/owner understands the potential work load.
Case study - Transition Town Monmouth
Log burning stoves range in size from 4-16kW and suit smaller scale (domestic) applications because they are manually loaded. They are available in many designs and sizes to suit all styles and needs. The stoves are the cheapest type of wood fuel appliance, making them ideal for lower cost projects. A stove with a water heating back boiler can be used to entirely run central heating and hot water, or supplement the existing heating system when used in combination with a primary boiler system. Room sealed stoves take air from outside rather than from the living area to provide draught, so warm air loss in the living space is hugely reduced.
For further help, download our useful guides;
A professional’s guide....
A householders guide.....