A Review on efficient thermal management of air- and liquid-cooled data centers: From chip to the cooling system

2017 ◽  
Vol 205 ◽  
pp. 1165-1188 ◽  
Author(s):  
Ali Habibi Khalaj ◽  
Saman K. Halgamuge
Keyword(s):  
Thermal Management ◽  
Data Centers ◽  
Cooling System

Perimeter Cooling Unit and Localized Row-Based Cooling Unit Transient Air Flow Effects Modeling and Characterization in Data Centers

2015 ◽  
Author(s):  
Tianyi Gao ◽  
James Geer ◽  
Bahgat G. Sammakia ◽  
Russell Tipton ◽  
Mark Seymour
Keyword(s):  
Thermal Management ◽  
Data Center ◽  
Data Centers ◽  
Cooling System ◽  
Air Flow ◽  
Cooling Systems ◽  
Dynamic Thermal Management ◽  
Hybrid Cooling ◽  
Cooling Unit ◽  
Cooling Air

Cooling power constitutes a large portion of the total electrical power consumption in data centers. Approximately 25%∼40% of the electricity used within a production data center is consumed by the cooling system. Improving the cooling energy efficiency has attracted a great deal of research attention. Many strategies have been proposed for cutting the data center energy costs. One of the effective strategies for increasing the cooling efficiency is using dynamic thermal management. Another effective strategy is placing cooling devices (heat exchangers) closer to the source of heat. This is the basic design principle of many hybrid cooling systems and liquid cooling systems for data centers. Dynamic thermal management of data centers is a huge challenge, due to the fact that data centers are operated under complex dynamic conditions, even during normal operating conditions. In addition, hybrid cooling systems for data centers introduce additional localized cooling devices, such as in row cooling units and overhead coolers, which significantly increase the complexity of dynamic thermal management. Therefore, it is of paramount importance to characterize the dynamic responses of data centers under variations from different cooling units, such as cooling air flow rate variations. In this study, a detailed computational analysis of an in row cooler based hybrid cooled data center is conducted using a commercially available computational fluid dynamics (CFD) code. A representative CFD model for a raised floor data center with cold aisle-hot aisle arrangement fashion is developed. The hybrid cooling system is designed using perimeter CRAH units and localized in row cooling units. The CRAH unit supplies centralized cooling air to the under floor plenum, and the cooling air enters the cold aisle through perforated tiles. The in row cooling unit is located on the raised floor between the server racks. It supplies the cooling air directly to the cold aisle, and intakes hot air from the back of the racks (hot aisle). Therefore, two different cooling air sources are supplied to the cold aisle, but the ways they are delivered to the cold aisle are different. Several modeling cases are designed to study the transient effects of variations in the flow rates of the two cooling air sources. The server power and the cooling air flow variation combination scenarios are also modeled and studied. The detailed impacts of each modeling case on the rack inlet air temperature and cold aisle air flow distribution are studied. The results presented in this work provide an understanding of the effects of air flow variations on the thermal performance of data centers. The results and corresponding analysis is used for improving the running efficiency of this type of raised floor hybrid data centers using CRAH and IRC units.

Steady State and Transient Experimentally Validated Analysis of Hybrid Data Centers

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Tianyi Gao ◽  
Bahgat Sammakia ◽  
Emad Samadiani ◽  
Roger Schmidt
Keyword(s):  
Steady State ◽  
Heat Exchanger ◽  
Thermal Management ◽  
Information Technologies ◽  
Data Centers ◽  
Cooling System ◽  
Hybrid Approach ◽  
Air Cooling ◽  
Air Conditioner ◽  
Density Data

Data centers consume a considerable amount of energy which is estimated to be about 2% of the total electrical energy consumed in the U.S. in the year 2010, and this number continues to increase every year. Thermal management is becoming increasingly important in the effort to improve the energy efficiency and reliability of data centers. The goal is to keep the information technologies (IT) equipment temperature within the allowable range in high power density data centers while reducing the energy used for cooling. In this regard, liquid and hybrid air/water cooling systems are alternatives to traditional air cooling. In particular, these options offer advantages for localized cooling higher power racks which may not be manageable using the room level air cooling system without requiring significantly more energy. In this paper, a hybrid cooling system in data centers is investigated. In addition to traditional raised floor, cold aisle-hot aisle configuration, a liquid–air heat exchanger attached to the back of racks is considered. First of all, the paper presents a review of literature of the study of this heat exchanger strategy in the thermal management of a data center. The discussion focus on rear door heat exchanger (RDHx) performance, both the steady state and transient impact are analyzed. The studies show that under some circumstances, this hybrid approach could be a viable alternative to meet the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recommended inlet air temperatures, while at the same time reducing the overall energy consumption in high density data centers. The hybrid design approach can also significantly improve the dynamic performance during rack power increases or computer room air conditioner (CRAC) unit failure. And then, additional parametric steady state and dynamic analyses, are presented in detail for the different scenarios.

scholarly journals PCM assisted heat pipe cooling system for the thermal management of an LTO cell for high-current profiles

2021 ◽  
pp. 100920
Author(s):  
Hamidreza Behi ◽  
Danial Karimi ◽  
Foad Heidari Gandoman ◽  
Mohsen Akbarzadeh ◽  
Sahar Khaleghi ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Thermal Management ◽  
Cooling System ◽  
High Current

Characterization of an Isolated Hybrid Cooled Server With Failure Scenarios Using Warm Water Cooling

2017 ◽  
Author(s):  
Uschas Chowdhury ◽  
Manasa Sahini ◽  
Ashwin Siddarth ◽  
Dereje Agonafer ◽  
Steve Branton
Keyword(s):  
Energy Consumption ◽  
Data Centers ◽  
Cooling System ◽  
Warm Water ◽  
Alternative Methods ◽  
Inlet Temperature ◽  
Cooling Efficiency ◽  
Water Cooling ◽  
Liquid Cooling ◽  
Total Energy Consumption

Modern day data centers are operated at high power for increased power density, maintenance, and cooling which covers almost 2 percent (70 billion kilowatt-hours) of the total energy consumption in the US. IT components and cooling system occupy the major portion of this energy consumption. Although data centers are designed to perform efficiently, cooling the high-density components is still a challenge. So, alternative methods to improve the cooling efficiency has become the drive to reduce the cooling cost. As liquid cooling is more efficient for high specific heat capacity, density, and thermal conductivity, hybrid cooling can offer the advantage of liquid cooling of high heat generating components in the traditional air-cooled servers. In this experiment, a 1U server is equipped with cold plate to cool the CPUs while the rest of the components are cooled by fans. In this study, predictive fan and pump failure analysis are performed which also helps to explore the options for redundancy and to reduce the cooling cost by improving cooling efficiency. Redundancy requires the knowledge of planned and unplanned system failures. As the main heat generating components are cooled by liquid, warm water cooling can be employed to observe the effects of raised inlet conditions in a hybrid cooled server with failure scenarios. The ASHRAE guidance class W4 for liquid cooling is chosen for our experiment to operate in a range from 25°C – 45°C. The experiments are conducted separately for the pump and fan failure scenarios. Computational load of idle, 10%, 30%, 50%, 70% and 98% are applied while powering only one pump and the miniature dry cooler fans are controlled externally to maintain constant inlet temperature of the coolant. As the rest of components such as DIMMs & PCH are cooled by air, maximum utilization for memory is applied while reducing the number fans in each case for fan failure scenario. The components temperatures and power consumption are recorded in each case for performance analysis.

Exergy Analysis of Data Center Thermal Management Systems

2003 ◽  
Author(s):  
Amip J. Shah ◽  
Van P. Carey ◽  
Cullen E. Bash ◽  
Chandrakant D. Patel
Keyword(s):  
Thermal Management ◽  
Data Center ◽  
Data Centers ◽  
Exergy Analysis ◽  
Thermal Control ◽  
Management Systems ◽  
World Systems ◽  
Sample Data ◽  
Potential Applications ◽  
Temperature Ranges

Data centers today contain more computing and networking equipment than ever before. As a result, a higher amount of cooling is required to maintain facilities within operable temperature ranges. Increasing amounts of resources are spent to achieve thermal control, and tremendous potential benefit lies in the optimization of the cooling process. This paper describes a study performed on data center thermal management systems using the thermodynamic concept of exergy. Specifically, an exergy analysis has been performed on sample data centers in an attempt to identify local and overall inefficiencies within thermal management systems. The development of a model using finite volume analysis has been described, and potential applications to real-world systems have been illustrated. Preliminary results suggest that such an exergy-based analysis can be a useful tool in the design and enhancement of thermal management systems.

Design and Analysis of an Aircraft Thermal Management System Linked to a Low-Bypass Ratio Turbofan Engine

2021 ◽  
Author(s):  
Robert A. Clark ◽  
Mingxuan Shi ◽  
Jonathan Gladin ◽  
Dimitri Mavris
Keyword(s):  
Thermal Management ◽  
Management System ◽  
Environmental Control ◽  
Cooling System ◽  
Heat Transfer Fluid ◽  
Turbofan Engine ◽  
Thermal Management System ◽  
Air Stream ◽  
The Impact ◽  
Bypass Ratio

Abstract The design of an aircraft thermal management system (TMS) that is capable of rejecting heat loads into the bypass stream of a typical low-bypass ratio turbofan engine, or a ram-air stream, is investigated. The TMS consists of an air cycle system (ACS), which is similar to the typical air cycle machines (ACMs) used on current aircraft, both military and commercial. This system turbocharges compressor bleed air and uses heat exchangers in a ram air stream or the engine bypass stream to cool the engine bleed air prior to expanding it to low temperatures suitable for heat rejection. In this study, a simple low-bypass ratio afterburning turbofan engine was modeled in NPSS to provide boundary conditions to the TMS system throughout the flight envelope of a typical military fighter aircraft. The engine was sized to produce sea level static (SLS) thrust roughly equivalent to that of an F-35-class engine. Two different variations of the TMS system, a ram air cooled and a bypass air cooled, were sized to handle a given demanded aircraft heat load, which might include environmental control system (ECS) loads, avionics cooling loads, weapons system loads, or other miscellaneous loads. The architecture and modeling of the TMS is described in detail, and the ability of the sized TMS to reject these demanded aircraft loads throughout several key off-design points was analyzed, along with the impact of ACS engine bleeds on engine thrust and fuel consumption. A comparison is made between the cooling capabilities of the ram-air stream versus the engine bypass stream, along with the benefits and drawbacks of each cooling stream. It is observed that the maximum load dissipation capability of the TMS is tied directly to the amount of engine bleed flow, while the level of bleed flow required is set by the temperature conditions imposed by the aircraft cooling system and the heat transfer fluid used in the ACS thermal transport bus. Furthermore, the higher bypass stream temperatures significantly limit the thermodynamic viability and capability of a TMS designed with bypass air as the ultimate heat sink. The results demonstrate the advantage that adaptive, variable cycle engines (VCEs) may have for future military aircraft designs, as they combine the best features of the two TMS architectures that were studied here.

Synchronreluktanz-Motorspindeln in Werkzeugmaschinen*/Synchronous reluctance motor spindles in machine tools – Energy-efficient drives increase accuracy and reduce cooling requirements of machining centers

2019 ◽  
Vol 109 (01-02) ◽  
pp. 72-80
Author(s):  
M. Weber ◽  
M. Helfert ◽  
F. Unterderweide ◽  
E. Abele ◽  
M. Weigold
Keyword(s):  
Thermal Management ◽  
Energy Efficient ◽  
Machine Tools ◽  
Production Management ◽  
Energy Savings ◽  
Cooling System ◽  
Holistic View ◽  
Synchronous Reluctance Motor ◽  
Management Technology ◽  
Reluctance Motor

Im Rahmen des vom Bundesministerium für Wirtschaft und Energie (BMWi) geförderten Projekts „ETA-Fabrik“ am Institut für Produktionsmanagement, Technologie und Werkzeugmaschinen (PTW) der Technischen Universität Darmstadt konnte die Energieeffizienz von Motorspindeln als Hauptenergieverbraucher von Werkzeugmaschinen durch Einsatz der Synchronreluktanztechnologie gesteigert werden. In der Konsequenz ergeben sich weitere Energieeinsparpotenziale und produktionstechnische Vorteile durch eine gesamtenergetische Betrachtung der Werkzeugmaschine mit Kühlsystem und intelligentem Spindelthermomanagement.   As part of the ‘ETA-Fabrik’ project funded by the BMWi, the Institute of Production Management, Technology and Machine Tools (PTW) of the TU Darmstadt has used synchronous reluctance drives to increase the energy efficiency of motor spindles as main energy consumers of machine tools. Subsequently, new opportunities for energy savings and advantages for the manufacturing process arise by taking a holistic view on machine tools including the cooling system, proposing an intelligent spindle thermal management.

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