1. AHU (Air Handling Unit) Function: Conditions and distributes air. Use: Large buildings. Cooling/Heating: Uses chilled/hot water or DX coil. Location: Centralized (mechanical rooms). 2. FCU (Fan Coil Unit) Function: Heats/cools air in small spaces. Use: Individual rooms or zones. Cooling/Heating: Uses chilled/hot water. Location: Decentralized (in rooms). 3. VAV (Variable Air Volume) Function: Controls airflow volume to zones. Use: Zoned air distribution. Cooling/Heating: Works with AHUs...