The indoor thermal environment of data centers is based on the supply airflow distribution

which is significantly affected by the geometric configuration of the air-supply system. This study compares four commonly used air supply layouts

namely the cold/hot-aisle airflow open-ended system

hot aisle containment system

cold aisle under racks system

and cold aisle containment system. For each air supply layout

geometric factors such as the plenum height

perforation rate

baffle position

and baffle angles were investigated. Using ANSYS Fluent

up to 288 models of CRAC with different air supply modes and configurations were built. The models were validated using the temperature measurement data at the SmartAisle? cold aisle containment system. The average rack and hot spot temperatures

thermal performance evaluation index

and return temperature index were used as the metrics for comparison. The results show that both increasing the plenum height and decreasing the perforation rate within a certain range contribute to thermal performance improvement. Considering the room temperature profile and evaluation metrics

the overall best performance is achieved in the cold aisle containment case. Finally

the effects of various factors when using \/-shaped and /\-shaped baffles were compared using the models of the cold aisle containment system. The results show that when using \/-shaped and /\-shaped baffles

the optimal perforation rate is 20%

while the optimal static pressure height is 0.5 m and 0.6 m

respectively. Overall

\/-shaped baffles achieve better temperature uniformity than /\-shaped baffles.