The higher heating value (HHV) is calculated as a weighted sum of elemental contributions from carbon, hydrogen, and sulfur in the fuel. The weights must be normalized fractions.

Normalization

First, normalize the fuel composition fractions:

\begin{equation}\label{eq:slfgm-norm-fuel-2} x_i = \frac{X_i}{\sum_j X_j}\end{equation}

Weighted Heating Value

Calculate heating value as weighted sum:

\begin{equation}\label{eq:slfgm-hv-calc} HV_{fuel} = x_C \cdot k_{HV,C} + x_H \cdot k_{HV,H} + x_S \cdot k_{HV,S}\end{equation}

Symbols

\(HV_{fuel}\)	Heating value of fuel \([\unit{ \btu\per\pound}]\)
\(x_C\)	Normalized carbon fraction \([\unit{ \unitless}]\)
\(x_H\)	Normalized hydrogen fraction \([\unit{ \unitless}]\)
\(x_S\)	Normalized sulfur fraction \([\unit{ \unitless}]\)
\(X_i\)	Percent of constituent i in fuel \([\unit{ \percent}]\)
\(k_{HV,C}\)	Heating value constant for carbon \([\unit{ \btu\per\pound}]\)
\(k_{HV,H}\)	Heating value constant for hydrogen \([\unit{ \btu\per\pound}]\)
\(k_{HV,S}\)	Heating value constant for sulfur \([\unit{ \btu\per\pound}]\)