Lower and Higher Heating Values (LHV and HHV)

There are two different types of heating value, which are the lower heating value (LHVClosedLower heat value) and the higher heating value (HHVClosedHigher heat value). By definition the higher heating value is equal to the lower heating value with the addition of the heat of vaporization of the water content in the fuel. These values can be measured in the laboratory for each type of fuel used in the kiln system. However, higher heating values must be converted, in order to obtain the correct values that should be used in the Plant sheet.

Mathematically the relation between both values can be expressed by the following formula [2006 IPCC Guidelines, Vol. II, Section, Box 1.1]

Equation 16: Conversion of higher to lower heating values in GJ/t (= MJ/kg)


  • HHV = Higher heating value
  • H = Percent hydrogen
  • M = Percent moisture
  • Y = Percent oxygen (from an ultimate analysis which determines the amount of carbon, hydrogen, oxygen, nitrogen and sulphur as received (i.e. includes Total Moisture (TM))

In the white cells in line132 to line137 the lower heating values (LHV) of conventional fossil kiln fuels can be entered:

Because in many plants some of the fossil kiln fuels are also used for other purposes, all following sections on LHVs of conventional fossil fuels use the values of the kiln fuels as default values. Those lines are of grey colour an can be overwritten for entering more specific values (as in the previous version of the CSI Protocol):

The lines turn into white colour when overwritten.