The aspect ratio in a rectangular duct refers to the ratio of its width to its height. Higher aspect ratios (narrow and tall ducts) are often preferred when space is limited, while lower aspect ratios (wide and short ducts) may be utilized in applications where lower pressure drop is desired.

This is because the fans in forced-draft towers create a high-pressure zone at the bottom of the tower, which forces air up through the tower. The air velocity is highest at the bottom of the tower and decreases as the air rises. The low exit velocity helps to prevent the droplets of water from being carried out of the tower.

more occupant-dense spaces like restaurants or classrooms may require higher ACH values compared to  office space

Evaporative cooling is a method of cooling that utilizes the principle of water evaporation to reduce the temperature of the air.

This is because the throw of the diffuser or grille is affected by the ceiling height. The throw is the distance that the airstream travels from the diffuser or grille before it loses its velocity.

These fans are known for their efficient performance and are well-suited for applications where a significant amount of airflow and pressure is required.

This is done to help the water droplets fall off the fins more easily and prevent them from clogging the fins.

HEPA filters are designed to remove 99.97% of airborne particles that are 0.3 microns or larger.

This is because outside air can contain pollutants, allergens, and other contaminants that can be harmful to human health. Positive pressure creates a barrier that prevents outside air from entering the conditioned space.

frictional loss is directly proportional to air velocity in the duct