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The calorific value of the different types of wood depends greatly on
their humidity and consequently the power of the fireplace heating
system 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 depending on its 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 relative to the unit of weight ( = absolute) id highest
in Conifers
Conifers absolute calorific value: 4700 Kcal/Kg
Broad-leaved species absolute calorific value: 4350
Kcal/Kg.
In opposition the
SPECIFIC WEIGHT
of the “broad-leaved species” is
greater; therefore equal volumes introduced into the fireplace heating
system, 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).
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 double that of
the fir. Therefore half the volume of oak must be introduced into the
fireplace heating system in order to have the same "heat" obtained
with the fir.
% of
humidity
Calorific value
kcal/kg
15%
3490
20%
3250
25%
3010
30%
2780
35%
2450
40%
2300
Содержание TKR 35
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