The higher heating value (HHV, also known as the gross
calorific value or gross heating value) is determined by
considering the cooling of reaction products to precombustion temperatures. Effectively, this means the latent
heat of liquids (in particular water) is included in the HHV. The
HHV is calculated with water exiting the system in liquid
form, while the LHV is calculated with the assumption that
the water product leaves as vapour. Various predictive equations have been developed for estimating the heating value of
solid fuels from their elemental composition. Here, two such
equations are used to estimate the HHV of the PKSB (using a
conversion of 1 Btu/lb ¼ 429.923 MJ$ kg1):