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In this paper, the performance of a parallel implementation of the phonon Boltzmann Transport Equation (BTE) is tested. Two three-phonon scattering models, the full scattering model and the anisotropic relaxation time model, are considered. The finite volume method is used to solve the Boltzmann Transport Equation (BTE) numerically. Two strategies are explored: spatial domain decomposition and phonon...
Fluid flow and mixed (free and forced) convection heat transfer characteristics over a micro-sphere at moderate to high values of both Grashof and Reynolds numbers are numerically investigated at uniform wall temperature boundary condition. Although this topic is crucial in understanding the basic flow and heat transfer features about a miniature sphere, little attention was drawn into it in the open...
The heat removal capability of area-interconnect-compatible interlayer cooling in vertically integrated, high-performance chip stacks was characterized with de-ionized water as coolant. Correlation-based predictions and computational fluid dynamic modeling of cross-flow heat-removal structures show that the coolant temperature increase due to sensible heat absorption limits the cooling performance...
The information technology industry, and consumers of the products and services stemming from the industry, has benefited from rapidly increasing computational performance for all classes of devices over the past several decades. With increased performance, the industry has also experienced a sharp increase in device-level energy consumption and power density. These trends are expected to result in...
Convective heat transfer from a vertically stacked [3-D] electronic package (die-stacking) mounted in between two circuit boards is numerically investigated. Heat transfer characteristics of single chip packages and multiple-die packages for both two and four die stack are presented and compared. The package Reynolds number, based on the package height and upstream velocity, ranges from 150 to about...
3D interconnect technology has attracted significant interest in the recent past as a means for enabling faster and more efficient integrated circuits (ICs). 3D integration relies on through-silicon vias (TSVs) and bonding of multiple active layers. While this approach provides several electrical benefits, it also offers significant challenges in thermal management. While some work has been done in...
Here we present a novel, measurement-based method for characterizing and improving the energy efficiency of a data center (DC). The technique not only yields a clear set of measurement-based best practices metrics, but also provides clear guidance to a DC manager to substantially improve the DC energy efficiency. We describe a technology which exploits the superiority of fast and massive parallel...
One of the most important parameters in the optimal ventilation of a raised air cooled data center is the amount of cool air that is delivered to the front of a server. It is very common in data centers for a significant fraction of the conditioned cool air to bypass the desired locations, i.e. the perforated tiles in front of the IT racks, and leak out through cable cutouts and other openings. This...
A software tool using a Genetic Algorithm (GA) has been developed to optimize the cooling performance of a cluster of equipment comprised of two approximately-equal-length rows of racks and coolers bounding a common hot-aisle. Such clusters are "room neutral" from a cooling-load perspective if most or all of the hot rack exhaust is captured locally by the coolers. A direct cooling-performance...
Server's capabilities are increasing at or beyond the rate of performance improvement gains predicted by Moore's Law for the silicon itself. The challenge for the information technology (IT) owner is housing and operating all of this computational power in the data center. With more computational power in each unit volume, the industry is experiencing a significant increase in power density and hence...
The growing energy consumption of computer data centers has recently received increased economic and environmental scrutiny. A significant portion of typical data center energy consumption can be apportioned to the cooling infrastructure. This paper shows the impact of heat load within the data center on the efficiency of the data center cooling ensemble, as measured in terms of a 'grand' Coefficient...
This paper is a continuation of the study (Iyengar et al., 2007) that describes the comparison of numerically-predicted and experimentally- measured temperature distributions in a small data center test cell. The data center cell has a floor area of 900 ft2 and comprises one rack, one air-conditioning unit, and perforated tiles. The Computational Fluid Dynamics (CFD) results in study (Iyengar et al...
Many factors, such as acoustic noise limits and fan reliability considerations, limit the heat dissipation capacity of air-cooled cabinets housing telecommunications or computing hardware. The present work examines the potential of enhanced cooling in a sealed telecommunications cabinet using an evaporating- condensing dielectric mist introduced upstream of heat sinks attached to high-power components...
New blade chassis designs, with banks of aggregate fans and system-level thermal architectures which precisely manage airflow, have enabled a new level of energy savings for enterprise customers that extends beyond the system and offers an opportunity for new system thermal design principles. By reducing system airflow rate to an absolute minimum, system fan power is minimized. More significantly,...
Design of high power data center with cost effective reliable cooling solutions is essential for reliability. Over designed cooling systems and rack layouts allowing mixing of air streams increase the energy consumption and cost of data centers. Air current mixing is a factor to control when looking to improve the thermal cooling performance in large data centers. In this work, real time temperature...
As part of the U.S. Department of Energy (DOE) Advanced Power Electronics (APE) program, DOE's National Renewable Energy Laboratory (NREL) is currently leading a national effort to develop next-generation cooling technologies for hybrid vehicle electronics. Spray cooling has been identified as a potential solution that can dissipate 150- 200 W/cm2 while maintaining the chip temperature below 125degC...
Thermal performance of louver fin, offset strip fin and plate fin in a thermoelectric cooling system with a duct-flow type fan arrangement is analytically examined. The thermoelectric cooling system is composed of a water jacket, an array of thermoelectric modules and a heat sink. Heat sinks with dimension of 39.7 mm times 119.1 mm plane area and 40 mm fin height are considered for the performance...
Driven by shrinking feature sizes, microprocessor "hot-spots" - with their associated high heat flux and sharp temperature gradients - have emerged as the primary "driver" for on-chip thermal management of today's advanced IC technology. Proposed uses of solid state thermoelectric microcoolers for hot spot remediation have included the formation of a superlattice layer on the back...
The power dissipated by electronic components has been steadily increasing, but financial and form factor restrictions exist on the cooling solution and the pressure is on to improve the power dissipation capability. The main parameter used for designing a component's cooling system is known as Thermal Design Power (TDP). This parameter is used as a steady state power target that the cooling solution...
Data center facilities house large number of computer servers that dissipate high power. With rapid increase in the heat flux of such systems, their thermal management has become a challenge that needs to be addressed. In this paper effect of isolating cold aisle on rack inlet temperature is studied computationally. Two raised floor data center configurations with alternating hot and cold aisle arrangement...
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