The heat input is calculated by multiplying the volumetric flow rate by the heating value of the gas and the operating time. The result is converted from Btu to MMBtu. If the heating value is zero or negative, the heat input is zero.

\begin{equation}\label{eq:flow-calculations-heat-input} Q_{input} = \frac{\dot{V} \cdot HHV \cdot t_{op}}{CF_{MMBtu}}\end{equation}

Symbols

\(Q_{input}\)	Heat input over operating period \([\unit{ \MMBtu}]\)
\(\dot{V}\)	Volumetric flow rate \([\unit{ \scf\per\hour}]\)
\(HHV\)	Higher heating value of gas \([\unit{ \btu\per\scf}]\)
\(t_{op}\)	Operating time \([\unit{ \hour}]\)
\(CF_{MMBtu}\)	Conversion factor to convert from Btu to MMBtu (1,000,000 Btu/MMBtu) - see physics::conversions::kMMBtuToBtu \([\unit{ \btu\per\MMBtu}]\)

Note: If HHV ≤ 0, then \(Q_{input}\) = 0.