Numerical and experimental study of air containment systems in legacy data centers focusing on thermal performance and air leakage

Abstract

With the increasing awareness of data center cooling and its impact on energy costs, hot-aisle containment (HAC) and cold-aisle containment (CAC) are considered vital techniques for IT environment control. Common data center cooling problems, which include air bypass and recirculation, are crucial to airtightness. The air leakage in an air containment is typically 10% or less. However, in practice, containment systems cannot guarantee complete airtightness, and do not function in the intended manner. In this study, both numerical and experimental studies were conducted to investigate the thermal performance of two systems. We found that there are operational differences that are significant factors influencing the amount of air leakage within the air containment systems. With an air leakage rate of 15%, the numerical simulation results show that selecting HAC, over CAC, can improve the thermal performance by 24.9%, corresponding to a 5.2% reduction in the return temperature index. The field measurements also show that HAC is more effective in cooling IT equipment. The supply air temperature of HAC can be raised by 2.0 °C; however, the IT operation environment will be similar to that of CAC. With an operational condition of high air leakage rate, HAC exhibits better thermal performance than CAC.