The need for more performance from computer equipment in data centers has driven the power consumed to levels that are straining thermal management in the centers. When the computer industry switched from bipolar to CMOS transistors in the early 1990s, low-power CMOS technology was expected to resolve all problems associated with power and heat. However, equipment power consumption with CMOS has been rising at a rapid rate during the past 10 years and has surpassed power consumption from equipment installed with the bipolar technologies 10 to 15 years ago. Data centers are being designed with 15-20-year life spans, and customers must know how to plan for the power and cooling within these data centers. This paper provides an overview of some of the ongoing work to operate within the thermal environment of a data center. Some of the factors that affect the environmental conditions of data-communication (datacom) equipment within a data center are described. Since high-density racks clustered within a data center are of most concern, measurements are presented along with the conditions necessary to meet the datacom equipment environmental requirements. A number of numerical modeling experiments have been performed in order to describe the governing thermo-fluid mechanisms, and an attempt is made to quantify these processes through performance metrics.

The effort described herein extends the use of least-material single rectangular plate-fin analysis to multiple fin arrays, using a composite Nusselt number correlation. The optimally spaced least-material array was also found to be the globally best thermal design. Comparisons of the thermal capability of these optimum arrays, on the basis of total heat dissipation, heat dissipation per unit mass, and space claim specific heat dissipation, are provided for several potential heat sink materials. The impact of manufacturability constraints on the design and performance of these heat sinks is briefly discussed.

No abstract

The increasingly ubiquitous nature of computer and internet usage in our society has driven advances in semiconductor technology, server packaging, and cluster level optimizations in the IT industry. Not surprisingly this has an impact on our societal infrastructure with respect to providing the requisite energy to fuel these power hungry machines. Cooling has been found to contribute about a third of the total data center energy consumption and is the focus of this study. In this paper we develop and present physics based models to allow the prediction of the energy consumption and heat transfer phenomenon in a data center. These models allow the estimation of the microprocessor junction and server inlet air temperatures for different flows and temperature conditions at various parts of the data center cooling infrastructure. For the case study example considered, the chiller energy use was the biggest fraction of about 41% and was also the most inefficient. The room air conditioning was the second largest energy component and was also the second most inefficient. A sensitivity analysis of plant and chiller energy efficiencies with chiller set point temperature and outdoor air conditions is also presented.

No abstract

No abstract

Increase in computing power resulting from high performance microprocessors, packages, and modules and the deployment of high heat load computer rack units in high density configurations, has escalated the thermal challenges in today’s data center systems. One of the key issues is the location of hot recirculation regions in the room and the mixing of hot rack exhaust air with the cold supply air. Along with many factors such as the rack heat load and the cooling capacity of the supply air, the data center thermal management architecture plays an important role in determining the reliability of the electronic equipment and the general thermal performance of the data center. There are several candidate configurations available for the air ducting designs for data centers. The overall energy efficiency of the system is highly dependant upon the selection of the specific configuration. This paper will summarize the results of a broad numerical study carried out to assess the effectiveness of different data center configurations. The numerical modeling is performed using a commercial computational fluid dynamics (CFD) code based on finite volume approach. The configurations studied include different combinations of raised floor and ceiling supply and return vent location subject to specific constraints. The performance of the data center has been characterized on the basis of average and maximum mean region rack inlet air temperature. Among the seven different configurations compared, the raised floor/ceiling return type configuration is found to be the most effective configuration for the given set of constraints and assumptions.

No abstract