The water saved is calculated from the condensate that can be returned to the boiler instead of being discharged. This is the net steam flow (excluding bypass) converted to volumetric flow and multiplied by the operating hours. The division by 1000 converts the mass flow (kg/hr) to volumetric flow (m³/hr) assuming water density of 1000 kg/m³. Returning condensate reduces the need for makeup water and provides both water conservation and energy savings benefits.

\begin{equation}\label{eq:water-heating-steam-water-saved} V_{saved} = \frac{(\dot{m}_{steam} - \dot{m}_{bypass}) \cdot t_{op}}{1000}\end{equation}

Symbols

\(V_{saved}\)	Annual water saved \([\unit{ \meter\cubed\per\year}]\)
\(\dot{m}_{steam}\)	Steam mass flow rate \([\unit{ \kilogram\per\hour}]\)
\(\dot{m}_{bypass}\)	Bypass steam flow \([\unit{ \kilogram\per\hour}]\)
\(t_{op}\)	Operating hours per year \([\unit{ \hour\per\year}]\)