Experimental and Computational Study of Multi-level Cooling Systems at Elevated Coolant Temperatures in Data Centers PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Experimental and Computational Study of Multi-level Cooling Systems at Elevated Coolant Temperatures in Data Centers PDF full book. Access full book title Experimental and Computational Study of Multi-level Cooling Systems at Elevated Coolant Temperatures in Data Centers by Manasa Sahini. Download full books in PDF and EPUB format.
Author: Manasa Sahini Publisher: ISBN: Category : Data libraries Languages : en Pages : 111
Book Description
Data centers house a variety of compute, storage, network IT hardware where equipment reliability is of utmost importance. Heat generated by the IT equipment can substantially reduce its service life if Tj,max, maximum temperature that the microelectronic device tolerates to guarantee reliable operation, is exceeded. Hence, data center rooms are bound to maintain continuous conditioning of the cooling medium. This approach often results in over-provisioned cooling systems. In 2014, U.S. Data center electricity consumption is about 1.8% of the total electrical energy in the country. Hence, data center power and cooling have become significant issues facing the IT industry. The first part of the study focuses on air cooling of electronic equipment at room level. Data centers are predominantly cooled by perimeter computer air handling units that supply cold air to the raised floor plenum and the cold air helps in removing the heat generated by IT equipment. This method tends to be inadequate especially when the average power density per rack rises above 4 kW. As a solution to mitigate this problem, different rack and row based cooling solutions have been proposed and used. The primary focus of these cooling methods is to bring cooling closer to the heat source which is the IT rack thereby improving the heat dissipation process along with controlled air flow management in the data center room. Mostly known close-coupled cooling solutions include rear-door heat exchanger, in-row coolers, and over-head cooling. In this study, a new end-of-aisle close-coupled cooling solution for small data center cooling room has been proposed. As oppose to the existing designs, this design is distinctive in eliminating the risk of placing the liquid on top of IT racks along with achieving cooling energy efficiency. Three different configurations of the proposed designs are studied for its thermal performance using computational modeling. The second part of the study focuses on liquid cooling at rack level. Liquid cooling addresses the critical issues related to typical air cooling in servers because of its better heat transfer characteristics. Water-cooling at the device level can be an efficient solution since water has higher thermal capacitance when compared to traditional heat carrying medium i.e., air. The emerging practice in the data center industry is to maximize the use of economizer usage by reducing/eliminating the usage of chiller while taking advantage of outside ambient conditions to cool the data centers. Liquid cooled racks are generally designed with different configuration of pumping systems. Empirical study is conducted on a state-of-art liquid cooled electronic rack for high coolant inlet, commonly known as warm-water cooling in order to evaluate the cooling performance of distributed vs. centralized coolant pumping systems. Experimental set up is instrumented such that detailed analysis is employed to study component temperatures as well as cooling performance of the rack at elevated inlet conditions. The third part of the study focuses on the impact of high server inlet temperatures to static power at server level. In order to maximize the use of economizers, the IT hardware will be exposed to higher inlet temperatures which would lead to higher operating temperatures of the processors. The operating temperature of the CPU has direct influence on the static power due to subthreshold leakage which is known to reduce the performance of the processor. The current work serves as a firsthand investigation to study trade-off between IT performance and energy efficiency for elevated inlet temperature in air vs. liquid cooled servers. Air cooled IT along with the liquid cooled counter-parts are instrumented and extensively tested to simulate the high ambient conditions at the test bed data center.
Author: Manasa Sahini Publisher: ISBN: Category : Data libraries Languages : en Pages : 111
Book Description
Data centers house a variety of compute, storage, network IT hardware where equipment reliability is of utmost importance. Heat generated by the IT equipment can substantially reduce its service life if Tj,max, maximum temperature that the microelectronic device tolerates to guarantee reliable operation, is exceeded. Hence, data center rooms are bound to maintain continuous conditioning of the cooling medium. This approach often results in over-provisioned cooling systems. In 2014, U.S. Data center electricity consumption is about 1.8% of the total electrical energy in the country. Hence, data center power and cooling have become significant issues facing the IT industry. The first part of the study focuses on air cooling of electronic equipment at room level. Data centers are predominantly cooled by perimeter computer air handling units that supply cold air to the raised floor plenum and the cold air helps in removing the heat generated by IT equipment. This method tends to be inadequate especially when the average power density per rack rises above 4 kW. As a solution to mitigate this problem, different rack and row based cooling solutions have been proposed and used. The primary focus of these cooling methods is to bring cooling closer to the heat source which is the IT rack thereby improving the heat dissipation process along with controlled air flow management in the data center room. Mostly known close-coupled cooling solutions include rear-door heat exchanger, in-row coolers, and over-head cooling. In this study, a new end-of-aisle close-coupled cooling solution for small data center cooling room has been proposed. As oppose to the existing designs, this design is distinctive in eliminating the risk of placing the liquid on top of IT racks along with achieving cooling energy efficiency. Three different configurations of the proposed designs are studied for its thermal performance using computational modeling. The second part of the study focuses on liquid cooling at rack level. Liquid cooling addresses the critical issues related to typical air cooling in servers because of its better heat transfer characteristics. Water-cooling at the device level can be an efficient solution since water has higher thermal capacitance when compared to traditional heat carrying medium i.e., air. The emerging practice in the data center industry is to maximize the use of economizer usage by reducing/eliminating the usage of chiller while taking advantage of outside ambient conditions to cool the data centers. Liquid cooled racks are generally designed with different configuration of pumping systems. Empirical study is conducted on a state-of-art liquid cooled electronic rack for high coolant inlet, commonly known as warm-water cooling in order to evaluate the cooling performance of distributed vs. centralized coolant pumping systems. Experimental set up is instrumented such that detailed analysis is employed to study component temperatures as well as cooling performance of the rack at elevated inlet conditions. The third part of the study focuses on the impact of high server inlet temperatures to static power at server level. In order to maximize the use of economizers, the IT hardware will be exposed to higher inlet temperatures which would lead to higher operating temperatures of the processors. The operating temperature of the CPU has direct influence on the static power due to subthreshold leakage which is known to reduce the performance of the processor. The current work serves as a firsthand investigation to study trade-off between IT performance and energy efficiency for elevated inlet temperature in air vs. liquid cooled servers. Air cooled IT along with the liquid cooled counter-parts are instrumented and extensively tested to simulate the high ambient conditions at the test bed data center.
Author: Uschas Chowdhury Publisher: ISBN: Category : Electronic data processing departments Languages : en Pages : 120
Book Description
The objective of this study is to improve and optimize the cooling efficiency of liquid and air cooling from server to room level while applying best practices in the industry. The effect of increased air and coolant temperature has been explored through a literature survey and studies are conducted from device level to room level for air and liquid cooling. Three major aspects are considered. A closed-form air cooling solution is proposed for high-powered racks in a modular data center equipped with in-row coolers. Direct-to-chip liquid cooling technology is extensively studied at the server level for raised air and coolant inlet temperature for determining thermal performance and reliability of IT equipment. A cost analysis for liquid cooling has been conducted with a TCO model for the performance improvement and holistic evaluation of a data center with air and liquid cooling.The first part consists of a room-level numerical study conducted with high powered racks in a modular data center with regular low-powered racks. Typical modular data centers are cooled by perimeter or outdoor cooling units. A comparative analysis is performed for a typical small-sized non-raised facility to investigate the efficacy and limitations of in-row coolers in thermal management of IT equipment with variation in rack heat load and containment. Several other aspects like a parametric study of variable opening areas of duct between racks and in-row coolers, the variation of operating flow rate, and failure scenarios are also studied to find proper flow distribution, uniformity of outlet temperature, and predict better performance, energy savings and reliability. The results are presented for general guidance for flexible and quick installation and safe operation of in-row coolers to improve thermal efficiency. The Second Part consists of a server-level numerical and experimental study with raised inlet air and coolant temperature for a hybrid cooled server. A detailed numerical study of an enterprise 1U hybrid cooled server is performed to predict the effect of raised inlet air temperature on the component temperatures following the limits of ASHARE air cooling classes. Then, an experimental study is performed in an environmental chamber with high inlet air temperatures. Results for both studies are compared. Previously warm water cooling or increased coolant inlet temperature has been experimentally tested on the respective server. Thus, the effect of both air and liquid coolant temperature has been presented and scaled up to a data center level with help of industry-standard tools for 1D flow network analysis to address the cooling efficiency improvement. The third part consists of a cost analysis of a data center with air and liquid cooling using an established TCO model. The ASHRAE cooling classes for air and liquid cooling are used based on the experimental findings. Also, the effect of cooling efficiency improvements at component and server level and increased inlet conditions are used to compare with a baseline model with air cooling.
Author: Chinmay Sanjay Kshirsagar Publisher: ISBN: Category : Languages : en Pages : 53
Book Description
As the worldwide demand for the data centers grows, so does the size and load placed on data centers which leads to the applied constraints on power and space available to the operator. Cooling power consumption is a major contributor of the total energy consumption of the system. In the process of optimization of cooling energy consumption per performance unit, liquid cooling technology has emerged as one of the most viable solutions. In this rack level study, 2OU (Open U) hybrid cooled web servers are tested for an evaluation of warm water cooling in centralized coolant system. Effects of higher inlet temperatures of the coolant in terms of device temperatures as well as IT and cooling power have been observed as a part of the evaluation. The study discusses the significance of variable pumping in centralized coolant system for its more efficient use. The experimental setup for cooling consists of 1/3rd sized mini rack capable of housing up to eleven liquid cooled web servers and two heat exchangers. The cooling configuration is centralized and has two redundant pumps placed in series with heat exchanger at the rack. CPUs of each server are liquid cooled with using passive micro channel cold plates while rests of the components are air cooled. Synthetic load has been generated on each servers for thermal stress testing and observed performance characteristics such as device temperatures and cooling power consumption of servers. Centralized redundant pumps are separately powered using an external DC power supply unit. The pump speed is varied with variable voltage supply ranging from 11V to 17V across the armature. The experimental testing is carried out at higher inlet temperatures ranging from 25°C to 45°C which falls within the ASHRAE liquid cooled envelope W4.Variable pumping at higher inlet temperatures has been achieved to evaluate to operating temperatures of device components for reliability and reduction in operational cooling power consumption of the servers.
Author: Charles Nehme Publisher: Charles Nehme ISBN: Category : Computers Languages : en Pages : 14
Book Description
Liquid cooling for data centers is a technological solution that helps keep computer hardware and other electronic devices running at optimal temperatures. It helps reduce costs associated with energy consumption by cooling the data center’s internal environment without the need for traditional air conditioning systems. Liquid cooling systems are built with a variety of components, including heat exchangers, pumps, hoses, and cooling towers. These components work together to exchange the heat generated from the components in the data center with a coolant, such as water or a refrigerant. The coolant is then cycled through the system and released into the environment, cooling the system and providing a more consistent temperature for the data center. Liquid cooling solutions provide an efficient and cost-effective means for data centers to maintain their optimal temperature and reduce the amount of energy required to run the system.
Author: Jun Dai Publisher: Springer Science & Business Media ISBN: 1461456029 Category : Technology & Engineering Languages : en Pages : 196
Book Description
This book describes the use of free air cooling to improve the efficiency of, and cooling of, equipment for use in telecom infrastructures. Discussed at length is the cooling of communication installation rooms such as data centers or base stations, and this is intended as a valuable tool for the people designing and manufacturing key parts of communication networks. This book provides an introduction to current cooling methods used for energy reduction, and also compares present cooling methods in use in the field. The qualification methods and standard reliability assessments are reviewed, and their inability to assess the risks of free air cooling is discussed. The method of identifying the risks associated with free air cooling on equipment performance and reliability is introduced. A novel method of assessment for free air cooling is also proposed that utilizes prognostics and health management (PHM). This book also: Describes how the implementation of free air cooling can save energy for cooling within the telecommunications infrastructure. Analyzes the potential risks and failures of mechanisms possible in the implementation of free air cooling, which benefits manufacturers and equipment designers. Presents prognostics-based assessments to identify and mitigate the risks of telecommunications equipment under free air cooling conditions, which can provide the early warning of equipment failures at operation stage without disturbing the data centers' service. Optimum Cooling for Data Centers is an ideal book for researchers and engineers interested in designing and manufacturing equipment for use in telecom infrastructures.
Author: Publisher: ISBN: Category : Aeronautics Languages : en Pages : 488
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: Amith Mathew Publisher: ISBN: Category : Languages : en Pages : 31
Book Description
Data centers are used by organizations for storing, processing and distribution of data. These data centers are run through-out the year due to which their thermal management is a growing concern. A popular way of eliminating such thermal cooling issues is Liquid cooling. Conventionally Liquid cooling involves the supply of constant liquid flow (water or refrigerant) through the IT rack irrespective of the IT load, which in a Multi-chip module causes hotspots and temperature gradients across the module due to non-uniform heating. A dynamic cold-plate and a regulatory flow control device (FCD) is incorporated in this experimental set-up to assist targeted delivery of coolant to the servers based on their IT load. A single high-power thermal test vehicle is used in each of the IT rack (simulating a processor). Dynamic cold plate is placed on the thermal vehicle accompanied by pressure, temperature, and flow sensors. The Flow control device is placed in the downstream of the manifold for regulation of the flow based on temperature of the coolant leaving from each server. The flow of each of the IT racks are monitored and varied based on the pressure of the system and the IT load on the server. This reduces the pumping power consumed by systemically varying the flow towards servers which withstand high IT load instead of constantly dispensing coolant to all the racks. Also due to the varying flow rates, the servers sustaining higher loads are provided with higher flowrates, hence increasing the reliability of the servers.
Author: Publisher: ISBN: Category : Languages : en Pages : 18
Book Description
Scientific and enterprise data centers, IT equipment product development, and research data center laboratories typically require continuous cooling to control inlet air temperatures within recommended operating levels for the IT equipment. The consolidation and higher density aggregation of slim computing, storage and networking hardware has resulted in higher power density than what the raised-floor system design, coupled with commonly used computer rack air conditioning (CRAC) units, was originally conceived to handle. Many existing data centers and newly constructed data centers adopt CRAC units, which inherently handle heat transfer within data centers via air as the heat transfer media. This results in energy performance of the ventilation and cooling systems being less than optimal. Understanding the current trends toward higher power density in IT computing, more and more IT equipment manufacturers are designing their equipment to operate in 'conventional' data center environments, while considering provisions of alternative cooling solutions to either their equipment or supplemental cooling in rack or row systems. In the meanwhile, the trend toward higher power density resulting from current and future generations of servers has created significant opportunities for precision cooling suppliers to engineer and manufacture packaged modular and scalable systems. The modular and scalable cooling systems aim at significantly improving efficiency while addressing the thermal challenges, improving reliability, and allowing for future needs and growth. Such pre-engineered and manufactured systems may be a significant improvement over current design; however, without an energy efficiency focus, their applications could also lead to even lower energy efficiencies in the overall data center infrastructure. The overall goal of the project supported by California Energy Commission was to characterize four commercially available, modular cooling systems installed in a data center. Such modular cooling systems are all scalable localized units, and will be evaluated in terms of their operating energy efficiency in a real data center, respectively, as compared to the energy efficiency of traditional legacy data center cooling systems. The technical objective of this project was to evaluate the energy performance of one of the four commercially available modular cooling systems installed in a data center in Sun Microsystems, Inc. This report is the result of a test plan that was developed with the industrial participants input, including specific design and operating characteristics of the selected modular localized cooling solution provided by vendor 3. The technical evaluation included monitoring and measurement of selected parameters, and establishing and calculating energy efficiency metrics for the selected cooling product, which is a modular, scalable liquid-rack cooling system in this study. The scope is to quantify energy performance of the modular cooling unit in operation as it corresponds to a combination of varied server loads and inlet air temperatures, under various chilled-water supply temperatures. The information generated from this testing when combined with documented energy efficiency of the host data center's central chilled water cooling plant can be used to estimate potential energy savings from implementing modular cooling compared to conventional cooling in data centers.
Author: Manasa Sahini
Author: Manasa Sahini
Author: Uschas Chowdhury
Author: Ali Cemal Benim
Author: Chinmay Sanjay Kshirsagar
Author: Charles Nehme
Author: Jun Dai
Author: 
Author: Amith Mathew
Author: 
Author: