International Fachagentur Nachwachsende Rohstoffe e. V.


Pellet boilers

Thanks to wood pellets, there has now been a new fuel on the market for about 15 years: it has given a powerful impetus to product development of highly efficient and particularly low-emission wood-fuelled heating units. There is a diverse product range of pellet-fuelled heating units and of pellet stoves for households, operating on water-based and air-based systems. Cookers fuelled by wood pellets are available, as are stoves with pellet modules: these can be fired by hand, using firewood and wooden briquettes or – e. g. if the home occupant is away during times of absence – automatically supplied with wood pellets.

Pellet heaters are also offered at very low heat-capacity levels, making them the ideal heating option for modern passive houses or low-energy houses. Here in many instances it is enough to have water-operating pellet stoves – mostly used in combination with solar thermal installations – to completely take over heating the home and also heating the water used for the home's other needs.

Pellet stoves and pellet boilers are also equipped with electronic control and adjustment, managing the supply of heating in accordance with needs and providing optimum, low-emission combustion at every stage in the spectrum of capacity use. In most instances, the control elements are arranged so as to serve several heating circuits in a targeted way, as well as bringing other heat generators into the system, e. g. solar thermal units and buffer storage units. Also available are pellet heating units with low-temperature capability: these are for buildings with floor-heating systems and wall-surface heating systems.

In a comparison among wood-fuelled heating systems, pellet-burning systems are for private households, the storage units for pellet-fuelled boilers are typically dimensioned in such a way that they can house the whole year's wood-pellet requirement. In that case, wood pellets are supplied in tank trucks and the vehicle blows them into the storage areas. In the case of large pellet-heating installations, the storage capacities are arranged in such a way that they can take receipt of a truck's whole supply load. The wood pellets are sent to the pellet-fuelled heating boiler from the storage room or the silo container: this is done fully automatically by a conveyor spiral or a pneumatic conveyor system.