In-Row Cooling

In-row cooling places cooling units between server cabinets in the same row rather than at the room perimeter. Cold air is thus delivered close to the heat source. Because the airflow path is short, in-row units handle higher densities than perimeter CRAC or CRAH units; deployments commonly target roughly 10–30 kW per rack, and well beyond that when combined with containment. Units draw hot air from the hot aisle and discharge cool air into the cold aisle, and they are typically fed by chilled water or refrigerant. They are modular, so capacity can be added row by row, which suits retrofits and phased colocation halls without raised floors. Limits are floor space taken from rack positions and the need for hydronic piping in the white space. For AI racks above about 40 kW, operators generally move to direct-to-chip liquid cooling.