Comparison Between Numerical and Experimental Results of Airflow Distribution in Diffuser Based Data Center

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Qifei Jian ◽  
Qiaoli Wang ◽  
Haoting Wang ◽  
Zheng Zuo
Keyword(s):  
Data Center ◽  
Distribution Systems ◽  
Volume Flow Rate ◽  
Mathematic Model ◽  
Experimental Results ◽  
Air Distribution ◽  
Test Results ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd

This paper studies the flow and temperature patterns in an overhead diffuser based data center. In-situ measurements of the data center were carried out to validate a mathematic model for predicting the effect of different air distribution systems. With the measured data of temperatures and airflow velocities, the mathematic model is constructed using a commercial Computational Fluid Dynamics (CFD) software and experimental data to present a comparison between test results and numerical simulations. The area of the data center is 311 square meters and the heat load of the equipment is 320~360 watt per square meter. In-situ temperatures and humidity of the data center were measured with an Automatic Temperature and Humidity measuring instrument, whose error is ±0.5 °C. The discrepancy of the temperature and velocity between the numerical and experimental results were within ±2.3 °C and ±1.8 m/s, respectively. In addition, analysis shows that changing the volume flow rate of the cold air delivered to some diffusers can optimize the temperature field and thereby save the energy.

Alternative Layouts for Air Distribution Improvement of a Computing Data Center

2013 ◽  
Vol 677 ◽  
pp. 282-285
Author(s):  
F.J. Wang ◽  
C.M. Lai ◽  
Y.S. Huang ◽  
J.S. Huang
Keyword(s):  
Data Center ◽  
Best Practice ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Cost Effective ◽  
Distribution Patterns ◽  
Air Distribution ◽  
Cooling Performance ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd

In this study, numerical simulation by using computational fluid dynamics (CFD) codes were conducted to investigate the influence of alternative layouts for air distribution in a full scale newly constructed data center. Through the simulation of different airflow distribution patterns in the data center, the optimum practice for cooling airflow arrangement can be identified easily. The simulation results also revealed that the best practice with a vertical under floor cooling architecture can provide satisfactory airflow distribution and thermal management. Higher cooling performance can be achieved by providing better separation of cold and hot aisle stream. Rack cooling index (RCI) has been used to evaluate the cooling performance of environmental conditions for the data center facility. Numerical study through CFD simulation can not only identify the best practice for airflow distribution, but also provide the energy-efficient and cost-effective HVAC system specific for data center facility.

scholarly journals A Comparative CFD Study of Two Air Distribution Systems with Hot Aisle Containment in High-Density Data Centers

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6147
Author(s):  
Jinkyun Cho ◽  
Jesang Woo ◽  
Beungyong Park ◽  
Taesub Lim
Keyword(s):  
Thermal Performance ◽  
Data Center ◽  
Distribution Systems ◽  
Data Centers ◽  
High Density ◽  
Operating Conditions ◽  
Air Distribution ◽  
Density Data ◽  
Computational Fluid Dynamics Analysis ◽  
Hard Floor

Removing heat from high-density information technology (IT) equipment is essential for data centers. Maintaining the proper operating environment for IT equipment can be expensive. Rising energy cost and energy consumption has prompted data centers to consider hot aisle and cold aisle containment strategies, which can improve the energy efficiency and maintain the recommended level of inlet air temperature to IT equipment. It can also resolve hot spots in traditional uncontained data centers to some degree. This study analyzes the IT environment of the hot aisle containment (HAC) system, which has been considered an essential solution for high-density data centers. The thermal performance was analyzed for an IT server room with HAC in a reference data center. Computational fluid dynamics analysis was conducted to compare the operating performances of the cooling air distribution systems applied to the raised and hard floors and to examine the difference in the IT environment between the server rooms. Regarding operating conditions, the thermal performances in a state wherein the cooling system operated normally and another wherein one unit had failed were compared. The thermal performance of each alternative was evaluated by comparing the temperature distribution, airflow distribution, inlet air temperatures of the server racks, and recirculation ratio from the outlet to the inlet. In conclusion, the HAC system with a raised floor has higher cooling efficiency than that with a hard floor. The HAC with a raised floor over a hard floor can improve the air distribution efficiency by 28%. This corresponds to 40% reduction in the recirculation ratio for more than 20% of the normal cooling conditions. The main contribution of this paper is that it realistically implements the effectiveness of the existing theoretical comparison of the HAC system by developing an accurate numerical model of a data center with a high-density fifth-generation (5G) environment and applying the operating conditions.

Analysis of Airflow Distribution Across a Front-to-Rear Server Rack

2007 ◽  
Author(s):  
Amir Radmehr ◽  
Kailash C. Karki ◽  
Suhas V. Patankar
Keyword(s):  
Boundary Conditions ◽  
Data Center ◽  
High Velocity ◽  
Critical Conditions ◽  
Airflow Distribution ◽  
Symmetrical Configuration ◽  
Computational Fluid Dynamics Cfd ◽  
Potential Failure ◽  
Cooling Air ◽  
Vertical Jet

The most common server racks in data centers are front-to-rear racks, which draw in the cooling air from the front side and discharge it from the backside. In a raised-floor data center the cooling air to these racks is provided by perforated tiles that are placed in front of them. In a high-density data center, these tiles discharge a considerable amount of airflow, which leads to a high-velocity vertical jet in front of the rack. Such a high-velocity jet may bypass the servers located at the bottom of the rack leading to their airflow starvation and potential failure. In this paper the effect of the high-velocity jet on the airflow taken by servers at various heights in the rack is studied. A computer model based on the Computational Fluid Dynamics (CFD) technique is used to predict the airflow distribution through servers stacked in the rack. Two cases are considered. In one case, the rack is placed in the middle of a row of racks in a prefect hot aisle-cold aisle arrangement. The boundary conditions around such a rack is symmetrical. In the other case, the rack is placed in a room with asymmetrical boundary conditions. The characteristics of the servers in the rack are taken from typical 1U and 2U servers manufactured by IBM. It is shown that in general the high-velocity jet has a mild effect on the airflow taken by the servers, and the airflow reduction is limited to servers at the bottom of the rack. Racks in a symmetrical configuration are more susceptible to the airflow starvation. In the most critical conditions, an airflow reduction of 15% is calculated for the server located at the bottom of the rack. Using the result obtained from the computational analysis, a simple model is developed to predict the reduction of the cooling air under the most critical situation for the server placed at the bottom of the rack.

Airflow and Cooling in a Data Center

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Suhas V. Patankar
Keyword(s):  
Fluid Dynamics ◽  
Data Center ◽  
Cfd Simulations ◽  
Flow Rates ◽  
Factors Affecting ◽  
Hot Air ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd ◽  
Cooling Air ◽  
Insight Into

This paper deals with the distribution of airflow and the resulting cooling in a data center. First, the cooling challenge is described and the concept of a raised-floor data center is introduced. In this arrangement, cooling air is supplied through perforated tiles. The flow rates of the cooling air must meet the cooling requirements of the computer servers placed next to the tiles. These airflow rates are governed primarily by the pressure distribution under the raised floor. Thus, the key to modifying the flow rates is to influence the flow field in the under-floor plenum. Computational fluid dynamics (CFD) is used to provide insight into various factors affecting the airflow distribution and the corresponding cooling. A number of ways of controlling the airflow distribution are explored. Then attention is turned to the above-floor space, where the focus is on preventing the hot air from entering the inlets of computer serves. Different strategies for doing this are considered. The paper includes a number of comparisons of measurements with the results of CFD simulations.

Airflow Distribution and Microenvironment Evaluation of MP Task Conditioning System

2007 ◽  
Author(s):  
Guozhong Zheng ◽  
Youyin Jing ◽  
Hongxia Huang ◽  
Lijun Shi
Keyword(s):  
Numerical Simulation ◽  
Velocity Distribution ◽  
Distribution Systems ◽  
Air Distribution ◽  
Hvac System ◽  
Breathing Zone ◽  
Airflow Distribution ◽  
Air Blowing ◽  
Clean Air ◽  
Supply Velocity

During recent years an increasing amount of attention has been paid to air distribution systems with which officer can individually condition the immediate environment of their workstations. Fanger suggested supplying ventilation air that is unmixed with room air, directly to the breathing zone of each occupant. Task conditioning aims to provide each occupant with personalized clean air direct to the breathing zone. Each occupant can control the environment at his/her workplace. Microenvironment of a typical office workplace consisting of movable panel (MP) task conditioning systems was studied by numerical simulation. MP task conditioning systems were operated while a conventional HVAC system supplied air through a diffuser located in the ceiling. Air was exhausted through a ducted ceiling-level grill. Numerical simulation of 3-D turbulent flow (k-ε closure) was separately conducted to study the influence of supply velocity, air blowing distance and size of MP supply outlet on microenvironment. Three task conditioning velocities, 0.6, 0.8 and 1.0m/s, three sizes 0.3×0.15, 0.3×0.1 and 0.25×0.08m and two air blowing distances were studied. In addition to analyzing temperature and velocity distribution, Draught Rating (DR) and Predicted Percentage of Dissatisfied (PPD) of the room and workstation were studied.

scholarly journals COMPARISON OF AIR DISTRIBUTION SYSTEMS IN ICE RINK ARENA VENTILATION

2013 ◽  
Vol 5 (4) ◽  
pp. 429-434 ◽  
Author(s):  
Agnieszka Stobiecka ◽  
Barbara Lipska ◽  
Piotr Koper
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Distribution Systems ◽  
Numerical Calculations ◽  
Air Distribution ◽  
Humid Air ◽  
Ice Surface ◽  
Ansys Cfx ◽  
Computational Fluid Dynamics Cfd

The paper presents the requirements and functions of ventilation in ice rink arenas and discusses difficulties and problems of ventilation in such objects. Particular attention has been paid to two types of inside used air distribution systems – traditional-integrated and modern-separated where the functions of tribune ventilation and dehumidification of the air over the ice surface were separated. The flow of humid air and heat in the designed hall was modelled numerically using the ANSYS CFX code based on computational fluid dynamics (CFD) technique. Air distribution systems in the ice rink arena were compared based on the results of numerical calculations.

Test Protocols for Combustion Turbine Inlet Cooling Foggers

2005 ◽  
Author(s):  
Philip Levine ◽  
Leonard C. Angello
Keyword(s):  
Heat Balance ◽  
Test Methods ◽  
Power Curve ◽  
Cfd Analysis ◽  
Test Results ◽  
Hot Wire ◽  
Test Procedures ◽  
State Water ◽  
Computational Fluid Dynamics Cfd

This paper on test protocols for combustion turbine (CT) inlet cooling investigates the instrumentation and methodology options available for testing fogger systems for cooling CT inlet air. Test protocols are presented for the steady state water balance and heat balance measurements. Estimated test uncertainties are presented for the direct measurement of cooling, heat balance, and power curve test methods. In-situ hot wire instrumentation is considered for measuring the carryover. The benefits of computational fluid dynamics (CFD) analysis are illustrated for guidance in the location and in defining the requirements of the instrumentation. Supporting test data for in-situ, heat balance, and power curve tests are included in the report. Test procedures and a method to correct the test results to the guarantee condition are presented. This investigation supports the development of code tests being developed by the ASME PTC 51 Committee.

scholarly journals Energy-Efficient Improvement Approaches through Numerical Simulation and Field Measurement for a Data Center

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2757 ◽  
Author(s):  
Fujen Wang ◽  
Yishun Huang ◽  
BowoYuli Prasetyo
Keyword(s):  
Numerical Simulation ◽  
Data Center ◽  
Cfd Simulation ◽  
Field Measurements ◽  
Heat Index ◽  
Temperature Index ◽  
Performance Indexes ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

The power density of electronic equipment increased dramatically recently. Data center and data processing and telecommunication facilities are facing the exceptionally high sensible heat loads which result in a large amount of energy consumption. In this study, a numerical simulation using computational fluid dynamics (CFD) was conducted to investigate the influence of alternative approaches to avoid bypassing and recirculation for air distribution in a full-scale data center. Field measurements were extensively conducted to validate the simulation results. Various performance indexes were adopted to enhance the evaluation of the thermal performance of the data center. The simulation results revealed that the practice with hot aisle enclosure and the installation of blocking panels for the unoccupied racks can provide satisfactory airflow distribution and thermal management under low load conditions. The return temperature index (RTI) can be improved by 3% through CFD simulation through installation of the blank panels, which reveals the reduction of recirculation airflow. The return heat index (RHI) increases by 8%, which presents a reduction of bypass airflow. A practical experiment using physical air curtains was conducted to enclose the hot aisle in the data center, which also reveals an 8% improvement for bypass airflow. Higher cooling performance can be achieved via reduction of recirculation and bypass airflow in the data center. Through the simulation of different improvement approaches in the data center, the optimum practice for cooling airflow arrangement can be identified accordingly.

Sign in / Sign up

Export Citation Format

Share Document