What Does Heating Value Mean?
Heating value is the amount of heat obtained when fuel or some other substance of a specific unit quantity is combusted. There are two types of heating values:
- The lower heating value (net) is the difference between combustion and latent heat of vaporization of the water vapors formed from combustion.
- The upper heating value (gross) is the heat obtained from complete combustion of a substance.
Corrosionpedia Explains Heating Value
The heating values of a fuel are mostly used to determine the fuel consumption of an engine or a machine. Other applications include calculations for overall energy efficiency of a system and analyzing cost-effectiveness of a combined heat and power plant. Normally, the upper heating value is quoted for fuel consumption, while the lower value is used for energy efficiency calculations. However, it is important to state the convention used to avoid any confusion.
The difference between the upper and lower heating value is related to the chemical composition of the fuel combusted. Heating values can be obtained experimentally by using a bomb calorimeter. For the upper value, the water produced from combustion must be in liquid form, while for the lower value it must be in a gaseous state.