HHV and LHV Calorific Values
A calorimeter measures the High Heating Value (HHV) because the combustion is contained in a closed environment (The combustion vessel). If the sample contains moisture and the sample material is used for heating (furnace) then part of the combustion energy is used for boiling the water and the resulting steam escapes through the chimney. The remaining energy is lower: the furnace is heated with LESS energy.
The following terminology is used:
- HHV: Higher Heating Value
- LHV: Lower Heating Value
- NCV: Nett Calorific Value
- LCV: Lower Calorific Value
The conversion from HHV to LHV is:
LHV(Btu/lb) = HHV(Btu/lb) – 10.55(W+9H)
Where: W = Weight% of moisture and H = Hydrogen
The DDS calorimeters can compensate for the moisture as part of the weight (Mass) of the sample. The moisture percent is deducted from the entered total mass resulting in a Nett Mass. The moisture percent is entered through the keyboard and has to be determined before by conventional procedures. Entering a slightly inflated moisture content will compensate for the heating loss of the evaporating moisture in the furnace.
