The heat value is
- the amount of heat produced by combustion a unit quantity of a fuel
We differentiate between gross and net heating values:
Gross (or high, upper) Heating Value
The gross or high heating value is the amount of heat produced by the complete combustion of a unit quantity of fuel.
The gross heating value is obtained when
- all products of the combustion are cooled down to the temperature before the combustion
- the water vapor formed during combustion is condensed
In thermodynamics, the term standard heat of combustion corresponds to Gross heating value. See Heat of combustion for examples of calculation of gross heating values from standard heat of formation of substances.
Net (or lower) Heating Value
The net or lower heating value is obtained by
- subtracting the latent heat of vaporization of the water vapor formed by the combustion
from the gross or higher heating value.
Common units for heating value:
- 1 Btu/lb = 2326.1 J/kg = 0.55556 kcal/kg
- 1 J/kg = 0.00043 Btu/lb = 2.39x10-4 kcal/kg
- 1 kcal/kg = 1.80 Btu/lb = 4187 J/kg
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Properties of alternative fuels like biodiesel, E85, CNG and more.
Energy content in biogas produced from municipal and industrial waste.
Heat of combustion (energy content) for som common substances - with examples how to calculate heat of combustion.
Heating fuels and their energy content.
Combustion heat values of some foods.
Combustion heat values for gases like acetylene, blast furnace gas, ethane, biogas and more - Gross and Net values.
Higher and lower calorific values (heating values) for fuels like coke, oil, wood, hydrogen and others.
Gross heat and net heat values for gases like hydrogen, methane and more.
Properties like heat values, air/fuel ratios, flame speed, flame temperatures, ignition temperatures, flash points and flammability limits.
Standard grades coal heat values.
Fuel from waste products and their heat values.
Combustion of wood and firewood heat values for species like Pine, Elm, Hickory and more.