Indoor ventilation and HVAC in large room

The video below shows a 4-hour transient of air renewal in a large room.

The red cloud refers to high concentrations of stale air (80-100%), the light blue cloud refers to low concentrations (0-20%).

The two sections also show the stale air concentration colour maps with isolines.

The simulation helps determining the time needed to renew the air, and to see where the air tends to stagnate