appliance is directly affected by the type of wood used, on average a well-seasoned wood has a calorific value of 3200
kcal/kg.
Calorific value of wood in relation to humidity:
CALORIFIC VALUE of the wood means the amount of heat yielded during combustion, referring to the unit quantity of
the material burned.
The calorific value of a wood species depends on the presence of lignin (6000 Kcal/kg) or cellulose (4000 Kcal/kg) as
well as the abundance of resin (8500 Kcal/kg).
The calorific value per unit of weight ( = absolute) is highest in Conifers.
- Absolute calorific value of conifers: 4700 Kcal/kg
- Absolute calorific value of broad-leaved species: 4350 Kcal/kg.
On the other hand the SPECIFIC WEIGHT of the “broad-leaved species” is greater; therefore with equal volumes
introduced into the appliance, both the weight and amount of heat available for combustion are greater; in practice the
relative calorific value is higher (referring to a unit of volume).
For example: the calorific value of the white fir is practically the same as that of the oak, but the oak has a specific
weight that is twice that of the fir. Therefore half the volume of oak must be introduced into the appliance in order to have
the same "heat" obtained from the fir.
To Next Page