Summary

Pellets are produced on an industrial scale from sawdust and wood shavings. These pressed objects are 6 to 8 mm thick and about 10 to 30 mm long, and there is a standard that guarantees consistent quality. Pellets are not only little bundles of energy (2 kg of pellets are the equivalent of 1 litre of fuel oil); they are also very easy to transport. Pellet-fired systems allow the continuous automatic combustion of a refined and well-defined fuel, with the burning rate controlled by the rate of fuel supply rather than by restricting the primary air. The fuel is fed automatically into the combustion chamber by means of an auger from a storage hopper. Some burners are equipped with a smaller pellet storage (enough for one or a few days of operation) that can be refilled manually or by an automatic system from a larger storage. Pellet heating facilities can be used with different systems like Pellets stoves, Pellet boilers or Pellet burners. Compared to a traditional wood burning stove, a pellet stove is more convenient to run, and its heating and combustion efficiency is much higher (it depends on the electricity used for its operation). The two main styles for pellet stoves are freestanding and fireplace insert models. Pellet burners for domestic use are usually constructed for a nominal thermal output of less than 25 kW. Depending on the feeding system, three different types of pellet burners can be identified with the flame burning either horizontally or upwards. Pellet boilers are often preferred for detached houses, because the fuel needs less space. Thanks to modern technology, a pellet boiler equipped with a fan or a screw conveyor can manage the flow of pellets required to produce the level of heat the user has determined. This is not only comfortable but also particularly efficient and environmentally-friendly. A small reservoir for buffer or hot water for use (boiler) is enough to store the heat produced by combustion. There is also an option to replace an oil burner in an existing heating boiler with a pellet burner. In this case it is important that the pellet burner is properly designed for the boiler. To complete the range, there are also combination boilers (as well as pellet stoves ) on the market that burn both pellets and firewood.

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