System Design Equations   Key System Design Equations   1 Total Dynamic Head (TDH) Equation Definition: Total energy added to fluid by pump, including static, pressure, velocity, and friction components. $H_{total} = H_{static} + H_{pressure} + H_{velocity} + H_{friction}$ $H_{total} = (z_2 - z_1) + \frac{P_2 - P_1}{\rho g} + \frac{V_2^2 - V_1^2}{2g} + h_f$