Lab-grown diamond heat spreaders are becoming attractive solutions compared to traditional copper heat spreaders due to their high thermal conductivity, the ability to directly bond them on silicon, and allow for an ultra-thin silicon layer. Researchers have developed various thermal models and prototypes of lab-grown diamond heat spreaders to evaluate their cooling performance and heat spreading ability. The majority of existing thermal models are built using finite-element method (FEM) based simulators such as COMSOL and ANSYS. However, such commercial simulators are computationally expensive and lead to long solution times along with large memory requirements. These limitations make commercial simulators unsuitable for evaluating numerous design alternatives or runtime scenarios for real-world high-performance processors. Because of this modeling challenge, none of the existing works have evaluated the thermal behavior of lab-grown diamond heat spreaders on real-world high-performance processors running realistic application benchmarks. Recently, we have developed a parallel compact thermal simulator, PACT, that is able to carry out fast and accurate steady-state and transient thermal simulations and can be extended to support emerging integration and cooling technologies. In this paper, we use PACT to evaluate the steady-state and transient cooling performance of lab-grown diamond heat spreaders against traditional copper heat spreaders on various real-world high-performance processors (e.g., Intel i7 6950X, IBM Power9, and PicoSoC). By using PACT with architectural performance and power simulators such as Sniper and McPAT, we are able to run transient simulations with realistic benchmarks. Simulation results show that lab-grown diamond heat spreaders achieve maximum temperature and thermal gradient reductions of up to 26.73 °C and 13.75 °C when compared to traditional copper heat spreaders, respectively. The maximum steady-state and transient simulation times of PACT for the real-world high-performance chips and realistic applications used in our experiments are 259 s and 22 min, respectively.

Electronic cooling represents a major portion of a Data Centers energy consumption, thus efficient thermal management dramatically impacts energy savings. This work proposes reducing the energy consumption associated with server air-cooling by vectoring (tilting) the main upward tile flow using adjacent synthetic jets. The particular fluid dynamics generated by synthetic jets allows controlling the angle at which the tile flow emanates, directing the cooling air toward areas with higher cooling demand. Three-dimensional simulations were performed using k – ε standard turbulence model with the commercial software Ansys Fluent. In order to quantify and localize the inefficiencies of the system, we estimated the Exergy Destruction distribution in the cold aisle and servers. In previous studies, this technique proved successful in finding optimum operation conditions in Data Center cooling. As opposed to a base case without flow control, the adjacent synthetic jets directed the incoming fluid to areas with higher cooling demand, thus saving energy by avoiding over-provisioning air into servers operating under normal demand. The decrease in the overall Exergy Destruction demonstrated that vectoring improves the system’s global energy efficiency.

Data centers are most commonly cooled by air delivered to electronic equipment from centralized cooling systems. The research presented here is motivated by the need for strategies to improve and optimize the load capacity and thermal efficiency of data centers by using computational fluid dynamics (CFD). Here, CFD is used to model and optimize the Villanova Steel Orca Research Center (VSORC). VSORC, presently in the design stages, will provide a testing environment as well as the capability to investigate best practices and state of the art strategies including hybrid cooling, IT load distribution, density zones, and hot aisle and cold aisle containment. The results of this study will be used in the overall design and construction of the aforementioned research data center. The objective of this study is to find the optimal operating points and design layout of a data center while still meeting certain design constraints. A focus is on finding both the ideal total supply flow rate of the air conditioning units and the ideal chilled water supply temperature (CHWST) setpoint under different data center design configurations and load capacities. The total supply flow rate of the air conditioning units and the supply temperature setpoint of the chilled water system are varied as design parameters in order to systematically determine the optimal operating points. The study also examines the influence of hot aisle and cold aisle containment strategies in full containment, half containment, and no containment configurations on the determined optimal operating conditions for the modeled research data center.

Thermoelectric modules utilize available temperature differences to generate electricity by the Seebeck effect. The current study investigates the merits of employing thermoelectrics to harvest additional electric energy instead of just cooling concentrating photovoltaic (CPV) modules by heat sinks (heat extractors). One of the attractive options to convert solar energy into electricity efficiently is to laminate TE modules between CPV modules and heat extractors to form a CPV-TE/thermal hybrid system. In order to perform an accurate estimation of the additional electrical energy harvested, a coupled field model is developed to calculate the electrical performance of TE devices, which incorporates a rigorous interfacial energy balance including the Seebeck effect, the Peltier effect, and Joule heating, and results in better predictions of the conversion capability. Moreover, a 3D multiphysics computational model for the hybrid concentrating PV-TE/thermal (CPV-TE/T) water collector system consisting of a solar concentrator, 10 serially-connected GaAs/Ge PV cells, 300 couples of bismuth telluride TE modules, and a cooling channel with heat-recovery capability, is implemented by using the commercial FE–tool COMSOL™. A conjugate heat transfer model is used, assuming laminar flow through the cooling channel. The performance and efficiencies of the hybrid system are analyzed. As compared with the traditional PV/T system, a comparable thermal efficiency and a higher 8% increase of the electrical efficiency can be observed through the PV-TE hybrid system. Additionally, with the identical convective surface area and cooling flow rate in both configurations, the PV-TE/T hybrid system yields higher PV cell temperatures but more uniform temperature distributions across the cell array, which thus eliminates the current matching problem; however, the higher cell temperatures lower the PV module’s fatigue life, which has become one of the biggest challenges in the PV-TE hybrid system.

Multicore microprocessor chips have emerged as an industry standard in recent years and have enabled Moore’s Law to be sustained when one considers the collective performance achieved by multiple cores. The industry has favored floor plans that use identical or symmetric layouts of individual cores in a linear array or a two-dimensional (2D) array, oblivious to the non-uniform heat dissipation within each core. Such non-uniform heat dissipations have hot spots within each core that must be aggressively cooled to avoid temporary or permanent device failures that can result from high temperature gradients. This paper evaluates alternative core layouts and microchannel configurations of a single-phase liquid cooling system for multi-core chips. We first examine the use of different planar flow patterns in microchannels for a realistic quad-core processor with non-uniform energy dissipation within each core. The direction of the flows in the microchannels is varied to achieve minimum hot spot temperatures on the die. A symmetric layout of the four cores with minimum achievable hot spot temperature is then selected and subjected to impingement flow. We establish the thermal efficiency of the optimized core floor plan compared to the traditional floor plan in a quad-core design and show that impingement provides the most efficient cooling solution compared to microchannels with planar flows for the same pressure difference.

There is a strong need to improve our current capabilities in thermal management and electronic cooling, since estimates indicate that IC power density level could reach 500 W/cm 2 in near future. This paper presents several possible closed and open loop cooling schemes for thermal management of electronic equipment in data centers. To be able to identify the overall energy consumption impact, a thermodynamics coefficient of performance (COP) analysis for a data center under each one of the proposed schemes is presented. A limited condition condition 2 nd law of thermodynamics thermal efficiency (η II ) analysis of the proposed open-loop schemes is also presented. Using available performance data, the overall data center COP of open and closed-loop cooling schemes is evaluated. Also, the 2 nd law efficiency of open-loop schemes is evaluated. To properly design and size the components of a liquid or refrigeration-assisted open or closed-loop cooling scheme requires heat exchanger modeling that need to be incorporated in existing CFD simulation models. For that, analytical modeling of two kinds of direct expansion refrigeration cooling evaporator and a secondary liquid cooling fan coil heat exchanger in conjunction with a computational fluid dynamics (CFD) model to analyze a refrigeration cooled high heat density electronic and computer data center installed on a raised floor is presented. Both models incorporate an accurate tube-by-tube thermal hydraulic modeling of the heat exchanger. The refrigeration coil analysis incorporates a multi region heat exchanger analysis for a more precise modeling of two phase refrigerant flow in the evaporator. The single phase secondary loop fan coil heat exchanger modeling uses an effectiveness method for regional modeling of the spot-cooling coil. Using an iterative method, results of the heat exchanger modeling is simultaneously incorporated in the CFD model and an optimal design of spot cooling heat exchanger is developed. The presented cooling schemes, theoretical thermodynamics analysis along with the detailed thermal-hydraulic heat exchanger simulation in conjunction with the state-of-the-art CFD simulation code should enable data center designers to be able to handle expected increased in heat density of the future data centers.

Thermal management difficulties in data centers caused by the rapidly increasing power densities of modern computational equipment are compounded by the less frequent upgrading of the facilities themselves, creating a lifecycle mismatch. This paper utilizes the Proper Orthogonal Decompostion (POD) for reduced order modeling of turbulent convection integrated with the compromise Decision Support Problem (DSP) using robust design principles. In the illustrative case study considered thermally efficient cabinet configurations that are insensitive to variations in operating conditions are determined. Results of the application of this approach to an enclosed cabinet example show that the resulting thermally efficient configurations are capable of dissipating up to a 50% greater heat load using the same cooling infrastructure.

A near CSP plastic encapsulated package with a quad flat non-leaded (QFN) structure has been drawn much attention due to it small size and lightweight applications. Thermal efficiency is the major concern for adopting such type of package in place of TSSOP package. The thermal dissipation for electronics with the higher power consumption is current developing to it uppermost limitation as a wire bonded, lead-frame substrate type of QFN with various pine counts and body sizes. It is therefore an object of the present study to investigate thermal performance of QFN package optimum design attached on different layers and thickness of laminated printed circuit board (PCB), which is further related to reliability issue of this type of IC package. Numerical simulation illustrates how the thermal efficiency of the QFN package can be reached with different PCB designs and airflow conditions.