Definition :
Calorific value is the amount of heat energy present in food or fuel and which is determined by the complete combustion of specified quantity at constant pressure and in normal conditions.
The value also called calorific power. The unit is kilojoule per kilogram i.e. KJ/Kg.
The efficiency of fuel or food mainly depends on the its value. If the value is high, its efficiency will also be high. If the value is low, its efficiency would also decrease. the CV is directly proportional to its efficiency.
The calorific value of a fuel is the amount of heat it generates on its complete combustion. For solid and liquid fuels, we express it in unit kJ/kg.
Furthermore, for the gaseous fuels, we express it as kJ/m3. Here m3 is a normal cubic meter that we measure at NTP conditions. Also, we can express the value of gaseous fuels as kJ per cubic meter which we express at STP conditions.
Types of calorific value (Higher and lower)
Higher Calorific Value
Gross CV of a fuel can be defined as the total amount of heat obtained on complete combustion of unit mass of a solid or liquid fuel or unit volume of a gaseous fuel (S T P) and on cooling the products of combustion to 15-degree c. The gross CV is also called a higher CV.
Lower Calorific Value:
Net CV is defined as the amount of heat obtained practically on complete combustion of unit mass of solid or liquid fuel or unit mass of solid or liquid fuel or unit volume of a gaseous fuel at step and the products of combustion are allowed to escape with some heat N.C.V also called as lower CV.
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