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There are various designs for segregating hot and cold air in data centers such as cold aisle containment (CAC), hot aisle containment (HAC), and chimney exhaust rack. These containment systems have different characteristics and impose various conditions on the information technology equipment (ITE). One common issue in HAC systems is the pressure buildup inside the HAC (known as backpressure). Backpressure also can be present in CAC systems in case of airflow imbalances. Hot air recirculation, limited cooling airflow rate in servers, and reversed flow through ITE with weaker fan systems (e.g. network switches) are some known consequences of backpressure. Currently there is a lack of experimental data on the interdependency between overall performance of ITE and its internal design when a backpressure is imposed on ITE. In this paper, three commercial 2-rack unit (RU) servers with different internal designs from various generations and performance levels are tested and analyzed under various environmental conditions. Smoke tests and thermal imaging are implemented to study the airflow patterns inside the tested equipment. In addition, the impact leak of hot air into ITE on the fan speed and the power consumption of ITE is studied. Furthermore, the cause of the discrepancy between measured inlet temperatures by internal intelligent platform management interface (IPMI) and external sensors is investigated. It is found that arrangement of fans, segregation of space upstream and downstream of fans, leakage paths, location of sensors of baseboard management controller (BMC) and presence of backpressure can have a significant impact on ITE power and cooling efficiency.
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Impact of Fans Location on the Cooling Efficiency of IT Servers
The role of data centers in modern life has expanded rapidly over the past decades. In addition, this expansion has resulted in a significant increase in the share of data centers in total energy consumption of the world. Thus, reliability and energy efficiency have become a common concern in data centers. Information technology equipment (ITE) and cooling infrastructure are the largest power consumer in data centers. The cooling power in a data center depends on the amount of heat dissipated by ITE. Therefore, the thermal design of the ITE impacts not only the ITE power but also affects the infrastructure power and has a significant role in the overall efficiency of data centers. This paper studies the impact of fans location and airflow balancing on the thermal performance and power of a server. A detailed computational fluid dynamic (CFD) model of the server is built, calibrated and validated using experimental test results. Next, impacts of moving fans to the rear side of the chassis on the flow rate and temperature of components are investigated. Special attention is given to controlling airflow through power supplies.
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- Award ID(s):
- 1738793
- PAR ID:
- 10095742
- Date Published:
- Journal Name:
- ITHERM
- ISSN:
- 1936-3958
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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