An Experimental Analysis of Hot Aisle Containment Systems

Abstract

In recent years, various airflow containment systems have been deployed in data centers to improve the cooling efficiency by minimizing the mixing of hot and cold air streams. The goal of this study is the experimental investigation of passive and active hot aisle containment (HAC) systems. Also investigated, will be the dynamic interaction between HAC and information technology equipment (ITE). In addition, various provisioning levels of HAC are studied. In this study, a chimney exhaust rack (CER) is considered as the HAC system. The rack is populated by 22 commercial 2-RU servers and one network switch. Four scenarios with and without the presence of cold and hot aisle containments are investigated and compared. The transient pressure build-up inside the rack, servers’ fan speed, inlet air temperatures (IAT), IT power consumption, and CPU temperatures are monitored and operating data recorded. In addition, IAT of selected servers is measured using external temperature sensors and compared with data available via the Intelligent Platform Management Interface (IPMI). To the best of authors’ knowledge, this is the first experimental study in which a HAC system is analyzed using commercial ITE in a white space. It is observed that presence of backpressure can lead to a false high IPMI IAT reading. Consequently, a cascade rise in servers’ fan speed is observed, which increases the backpressure and worsen the situation. As a result, the thermal performance of ITE and power consumption of the rack are affected. Furthermore, it is shown that the backpressure can affect the accuracy of common data center efficiency metrics.