lower heating value(LLV)

What is lower heating value(LLV)?

lower heating value(LLV) meaning The heat produced by combusting one unit of a substance, at atmospheric pressure, under conditions such that all water in the products remains in the form of vapor. The net heat of combustion is calculated from the gross heat of combustion at 20oC by subtracting 572 cal/g (1,030 Btu/lb) of water derived from one unit mass of sample, including both the water originally present as moisture and that formed by combustion. This subtracted amount is not equal to the latent heat of vaporization of water because the calculation also reduces the data from the gross value at constant volume to the net value at constant pressure.

 

reference: Glossary – Energy Efficiency & Renewable Energy