Building Air Flow Balance

For a given set of room conditions (temperature and humidity) MacroFlo solves the air flow problem by balancing net air mass flows into and out of each room. The components of this air flow balance are:

Net air inflow for each of the room’s openings, calculated as described above.
Any net room airflow imbalance imposed by the system simulation program APhvac.

Within each room there is assumed to be no pressure variation except the density-related variation with height.

The network of flow and pressure relationships is solved by linearisation and iteration. The result of this calculation is a set of values for the room pressures extrapolated to the ground level datum, p _n(0) , together with flow rates in each direction through each opening. The criterion for convergence is that each room’s mass flows should balance to an accuracy of 0.0001 kg/s.