The pressure losses at the nodes of a duct system will always be balanced naturally. If the design does not provide this balancing, the flow will balance itself. The system's total airflow and pressure loss will be in accordance with the fan's performance curve. In other words, the system will move an amount of air that equalizes the energy transferred to the air by a fan with the amount of energy converted to waste heat by ductwork friction, dynamic loss, and air property changes. Flow distribution in a duct system is calculated to study a system's performance and control. A complete ductwork simulation program predicts the actual air-flow balancing in each branch of a duct system [T-Duct, 1994; AABC, 1983 ref148].
