Alternative energy

Biomasses a sure system for your heating

Par le Doc. Luca CARGNINO

Types of biomass :

1. wood
2. pellets
   

The wood: ancient man's friend and modern man heating system.
The wood is one of the most precious materials the nature offers. It has been used by the man in order to not only heat itself, but also for the construction of objects and several tools. The progress has made possible the use of the wood also in the building field, in naval industry, and in the industrial production in order to obtain, for example, the cellulose with which the paper is made.
The firewood is formed essentially from lignite cellulose and it contains also other substances, of which firs and pines are rich, as resins and much water.

To the aims of the heating, it is necessary to assess itself that the characteristics of the firewood satisfy some important requirement, the most important of which is the corrected seasoning and drying, in other words the firewood must possess the humidity degree around the 10-15%, so it is important also the period of the year in which it comes cut that it would have to coincide with the winter period. The corrected seasoning allows having a good and little polluting fuel.

The conservation must happen in repaired and very airy places, the wood should be cut in adapted pieces for the combustion chamber. It is necessary to keep in mind that also the dimensions of the cut have their importance according to the phase of combustion , of the type of combustion chamber  (stoves, fireplace, boiler) and of the economic convenience ( little pieces   cost more than the bigger ones for the greater time that is necessary to employ to cut little sizes).

The firewood is divided in: sweet firewood and hard firewood according to the weight in kg of a cubic meter of material. The sweet firewood, that weights approximately 300 - 350 kg/m3, is  that of fir, pine, poplar, alder, chestnut tree, willow, while the hard one weights  approximately 350 - 400 kg/m3 and it is  that of elm tree, oak, holm oak, beech and ash tree.

The sweet firewood is fired easily, it is consumed in a hurry and it develops a long flame and it is used into the ovens that demand along flame turn. The hard firewood instead, is more compact, the combustion is slower with short flames, harder and is used for domestic heating.
The firewood, to the aims of the heating, introduces various characteristics according to the tree variety from which it is obtained. Not  all the woods are  equal and the characteristics about  the time of drying and the heat power  vary from tree to tree.
The heat power depends on the humidity degree and  on its density. The woods of optimal quality are the oak, the beech, the ash tree, maple tree, and the fruit trees less than the cherry tree. Of discreet quality  are instead the chestnut tree, the birch, and the alder. Of acceptable quality are the lime tree,  the poplar and the willow. To avoid the resins woods in general terms.

 
Sawdust the refuse transformed in a modern system of heating :

What pellet is? The pellet is made by the sawdust that is the virgin residual of the working of the wood, opportunely seasoned and pressed in order to obtain little cylinders of varied largeness. Thanks to the  binder characteristic  of  the lignin, a  natural substance  contained in the firewood, it is not necessary to add any type of additive so a natural, ecological and height  efficient fuel is obtained. Ideal for feeding heating machines, the pellet, is clean, not polluting and neutral CO2. It burns completely with minimal residual ashes that can be used as a  precious fertilizer for the garden. Because of the pressing  in the phase of production, the energetic density of the pellet is approximately the double  of that of the wood. The Pellet is used both for  stoves  for the heating of single rooms and for  boilers for the centralized heating.
Packing :
The pellets  are available in: bags of Kg. 15 for the sale by retail  they are transported on benches (pallet) that  can  contain from 60 to 90 bags (according to the producer) so as to have an all up weight around the 10 quintals , in big bags from 600 to 1000 kg (1 ton) or   in bulk
Why to use the Pellet?

The prices of fuel and the pellet  thermal characteristics of can vary.
Why   is  it ecological:
Pellet is produced with the wood  sawdust  taking advantage of the properties of lignin and therefore without  the addition of binders and chemical additives.
It produces little smoke and it is neutral CO2, it is a  renewable fuel  and frees much carbon dioxide as much the plant has absorbed from the  atmosphere during  the photosynthesis. The residual ashes are minimal, always inferior at  1% of the weight of the fuel.
Why is it practical ?
Pellet can be seasoned  in little space as its energetic density is approximately the double quantity of that of the wood. The supplying is also facilitated  by the fact that  now the pellet is distributed in capillary way and this allows also not having a warehouse where to stock it. Thanks to its closeness also the transport  is easier and more economic . The pellet  is a clean fuel and the little residual ashes can be removed and  discharged with more facility.
Why is it sure?
Pellet is sure above all for the fact that is neutral CO2, it is surer than the   fossil  combustibles  because less inflammable. The lack of binders, additives, paints and chemical products  in pellet renders it less toxic.