Optimization of Cold Aisle Isolation Designs for a Data Center With Roofs and Doors Using Slits

Abstract

Data centers are facilities that house large numbers of computer servers that typically dissipate high power. With the rapid increase in the heat flux of such systems, their thermal management represents an economic and environmental challenge that needs to be addressed [2]. Considering the trends of increasing heat loads and heat fluxes, the focus for users is in providing adequate airflow through the equipment at a temperature that meets the manufacturers’ requirements. Data centers house IT equipment in racks typically arranged in rows which face one another. Alternating cold and hot aisles are formed and this pattern is repeated across the data center. This approach helps to separate cold and hot air streams; but this does not always suffice in the separation of cold and hot air. The mixing of hot rack exhaust air with cold supply air, short-circuiting of cold air to the coolers and the recirculation of hot air to racks’ inlet are the common phenomena that lead to thermal inefficiencies in a typical data center. Typically in a raised floor data center, increase in rack inlet air temperature is seen because of the infiltration of hot air into the cold aisle from the top (ceiling of the cold aisle) and from edges or sides. Infiltration can be reduced to a certain extent if cold aisles are isolated from ceiling and hot aisles using partially or fully closed doors with slits to manage the airflow. The key is to redistribute the cold air entering the cold aisle along with any infiltration such that the overall average temperature at the rack inlets is below a predefined level. In this paper, different designs were generated with the criteria of achieving no hotspots, a relatively low pressure drop across the servers and low velocity of the air in the cold aisle based on an actual data center model. Several designs are proposed that meet all of the defined constraints.