Computer systems have been a source of high power dissipation either from microprocessors, memory and supportchips and mass storage. A high thermal density data center using these computer systems has resulted in a very highpower density at room level. These computer systems are represented by and included in a rack. Normally a standardrack is two meters high and can accommodate an equivalent of 34 thin desktop computer systems. If each systemconsumes around 300 W, a standard rack in a data center can consume up to 7.2 kW. While a data center can beconsisted of hundreds of racks, this results in very high heat dissipation in the data center. For the racks to operate atnormal operating conditions, a suitable air conditioning system should be designed to remove the high heat dissipation.Using simple energy balance and steady state analysis is no longer adequate to rely on for a proper design and analysis ofair flow and temperature distributions in a data center. In this paper, a computational fluid dynamics (CFD) model of aprototype data center is presented to make the case for such modeling. The study is carried out using CFD simulationtechniques as embedded in the commercially available CFD code (ANSYS V.16). The CFD modeling techniques solvedthe continuity, momentum and energy conservation equations in addition to standard k - ε model equations forturbulence closure.