Effect of CRAC location on fixed rack layout

Microprocessor driven escalation of thermal management needs has resulted in significant cooling challenges at the data center facility level, which can house thousands and tens of thousands of heat producing processors. Raised floor air ducting is the most common configuration, where chilled air from the air conditioning units is forced into the room via a under floor plenum and through perforated tiles on the floor. The hot air from the racks finds its way to the top of the air conditioning units and is then cooled and blown into the under floor plenum. The temperature at inlet of the racks is the key performance metric in evaluating the cooling performance data center facility. This rack inlet temperature is influenced by the air flow patterns within the room, which in turn is a function of several different factors such as the rack flow rates, the perforated tile location, the CRAC location, the room dimensions and geometry. In this paper the effect of the CRAC location of a fixed rack layout is studied. A representative raised floor data center was numerically modeled using commercially available software. The results of the simulations are utilized to gain insight into the flow patterns and the data from the parametric analysis is used to quantify the effect of CRAC (chilled air conditioning unit) location with respect to the computer racks.