The energy density refers to the amount of heat that we can “pull” through the combustion of biomass. It inherently varies, depending on the variety of origin. For the purposes of an accurate assessment of this value, as of all the other variables mentioned here, there are possibilities for specific analyzes. However, at least with regard to the solid fuel for excellence, the wood chips, there are technical standards that help in the process of comparison and evaluation.
In fact, the qualitative characterization of this fuel is regulated by the specific EU CEN / TS 14961 of 2005 which examines, among others, parameters such as:
- the magnitude of the size
- the moisture content
- the content of dry substance
Of crucial importance is the water content, as inversely proportional to the energy yield. In fact, the gross calorific value (Table 3) is a theoretical data which, during the combustion reaction, is reduced in terms of the heat quantity necessary to the evaporation of the water content of wood (heat of evaporation of water). Remember that this reduction is substantial, given that with a water content (M) of 40% (u = 67% humidity) the calorific value is reduced by almost 50%