What is the function of a CRAH unit in a data center?

The function of a Computer Room Air Handler (CRAH) unit in a data center primarily involves using chilled water for cooling. CRAH units are designed to manage the thermal conditions within the data center environment by facilitating the distribution of cool air, typically produced by leveraging chilled water sourced from a central chilling plant.

In this operation, the CRAH unit draws in warm air from the data center, which is passed over a cooling coil that contains chilled water. As the warm air comes in contact with the chilled water within the coil, it loses heat and is cooled down before being reintroduced into the data center. This process is essential for maintaining optimal operational temperatures for the servers and other critical equipment.

While airflow is a significant element in how cooling is delivered, the primary mechanism of the CRAH unit is its reliance on chilled water to effectively lower air temperature. This makes the use of chilled water a crucial aspect of a CRAH unit's functionality, aligning with the primary answer.