This chapter extends energy conservation principles to flow and transport phenomena, focusing on steady-state systems like fluid flow and electric circuits. We develop the Steady-State Energy Density ...This chapter extends energy conservation principles to flow and transport phenomena, focusing on steady-state systems like fluid flow and electric circuits. We develop the Steady-State Energy Density Model and the Linear Transport Model for processes that remain constant over time. In the final part, we explore exponential growth and decay in systems evolving toward equilibrium, linking steady-state and time-dependent behaviors.