Modern wood burners can provide cost-effective and highly efficient heating options. These can be suitable for schools, commercial buildings and other large users of heat at a range of scales.
Many schools, hospitals and industries in Europe and North America use wood pellet and wood chip boilers because they are safe, clean, reliable and economical.
The main fuel requirements for efficient burning of woody biomass are moisture content, fuel consistency, and low contamination levels. For this reason, wood chips or pellets are considered most suitable for commercial heating applications.
There are many types of combustion appliances designed specifically for either wood chips or wood pellets, depending on fuel preference and availability. These burners can be as fully automated as systems designed to burn oil, diesel or gas.
The suitability of wood chips versus pellets depends on your location and handling facilities.
Wood pellets offer space-saving, quality and handling advantages over wood chips. Pellets are a more homogenous, refined fuel and so can be more expensive than wood chips, depending on supply. The pellet market already has several suppliers with more production facilities being planned.
Wood chips are a by-product of sawmilling, arboricultural and forestry activities, therefore they can be sourced all over New Zealand. Currently there is no New Zealand standard for woody fuels so buyers must ensure the wood chips are suited to their needs.
There are several types of woodchip boiler on the market and each type has its own advantages. The boilers are characterised by the type of combustion and feed mechanisms, such as grate furnaces, under-feed stokers, or fluidised bed combustors.
Using modern technology, wood chips can be burned efficiently up to 55% moisture content (wet basis).
Wood chip boilers are capable of using either chip or pellets. Modern wood chip boilers are fully automated with automatic tube cleaning, automatic starting and automatic de-ashing, With efficiency levels of up to 93% such boilers offer levels of performance and convenience comparable to oil or diesel systems.
Wood-fired boilers use heat exchange surfaces to heat water, or to make steam if required for industrial processes. Hot water can be used for space heating using under-floor, radiant, ceiling and forced air central heating. Any user of large quantities of hot water (e.g., hotels, prisons etc) is well-suited to making the switch to wood chip.
Read more about woodchip burners...more
Wood pellet fires are very efficient heating appliances that come in a range of sizes and styles. They are suitable for both domestic and commercial applications.
Similar in principle to woodchip burners, wood pellet boilers are recommended for the domestic sector and commercial applications where there are space constraints. Some existing coal boilers can be converted to burning wood pellets. In Rotorua, five school coal boilers have been converted to wood pellet boilers. Several South Island schools have also undergone this conversion.
Read more about the school conversions to wood pellets: