Impact of Overhead Air Supply Layout on the Thermal Performance of a Container Data Center

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Wen-Xiao Chu ◽  
Jui-Lin Wu ◽  
Yeng-Yung Tsui ◽  
Chi-Chuan Wang
Keyword(s):  
Thermal Performance ◽  
Data Center ◽  
Hot Spot ◽  
Small Diameter ◽  
Heat Index ◽  
Spot Area ◽  
Hot Air ◽  
Air Supply ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact

Abstract This study focused on the improved designs of airflow management in container data centers having overhead air supply. The computational fluid dynamics (CFD) model is first validated with experimental results. Then, the impact of grille diameter, deflector angle, and air supply layout on the data center thermal performance is investigated. The results show that the larger grille diameter may reduce the volumetric flowrate through the upstream grille, causing insufficient air supply and strong hot-air recirculation at the first rack A1. By decreasing the grille diameter from 335 mm to 235 mm, the average rack cooling index (RCI) and supply heat index (SHI) can be improved from 25.4% and 0.292 to 65% and 0.258, respectively. However, implementing small diameter grilles is not an economic way for data center performance improvement as far as the energy consumption is concerned due to the high pumping power. Meanwhile, raising the deflector angle below 30 deg in grille S1 can provide moderate improvement on temperature of the A1 rack. A further rise in the deflector to 40 deg may impose severe deterioration with a pronounced hot-spot area. The data center performance can be improved by changing from center-cold-aisle arrangement to center-hot-aisle layout. The layout provides much higher return air temperature and the RCI and SHI can be improved by 32.7% and 34.5%, respectively.

Advanced Data Center Cold Aisle Airflow Organization Optimization Using an Adjustable Fan Unit

2020 ◽  
Author(s):  
Zhihang Song ◽  
Qian Zhang
Keyword(s):  
Data Center ◽  
Early Stage ◽  
Hot Spot ◽  
Temperature Drop ◽  
Negative Effects ◽  
Hot Air ◽  
Data Center Cooling ◽  
Efficient Data ◽  
Smart Data ◽  
Computational Fluid Dynamics Cfd

Abstract The real-time smart data center cooling has become a key to maintenance and operation of energy-efficient data centers, primarily including the server inlet airflow/thermal domains. Here, the cold-aisle airflow phenomena in a widely-used cold/hot aisle data center configuration was under parametric investigation, This concern is mainly because of the airflow separation and recirculation from the stream emerging from the server outlet and returning to the computer room air-conditioning unit. In order to achieve a better understanding and to correspondingly eliminate the negative effects of the hot air over-tack recirculation towards a satisfied effectiveness, an addition of a rack-level adjustable fan unit (AFU), which is placed inside the cold aisle, was considered at an early stage and the model prototype was numerically analyzed with respects to differently predefined parameters. The cooling performance consequence, consisting of the server-neighbored inflow rates and maximum server inlet temperatures explored by computational fluid dynamics (CFD) observation panel and sensors, demonstrates that the over-rack air recirculation and its resulting hot spot, in comparison with the case in absence of the AFU, can be suppressed. The results additionally concludes the extents to which the optimized airflow organization and temperature drop of the rack-level region (e.g., from the bottom towards the top of the rack unit) can be achieved with/without the AFU addition.

Airflow Management on the Efficiency Index of a Container Data Center Having Overhead Air Supply

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Cheng-Hao Wang ◽  
Yeng-Yung Tsui ◽  
Chi-Chuan Wang
Keyword(s):  
Temperature Distribution ◽  
Flow Rate ◽  
Data Center ◽  
Hot Spot ◽  
Efficiency Index ◽  
Test Results ◽  
Air Flow Rate ◽  
Hot Air ◽  
Air Supply ◽  
Small Container

Effect of airflow managements on the efficiency index of a small container data center having overhead air supply is reported in this study. Seventeen arrangements and configurations regarding the airflow and blockage arrangements are experimentally examined and compared. Test results indicate an appreciable hot air recirculation occurring for rack arrangement without any blockage, and the hot spot occurs at the second rack alongside the cold aisle. The hot spot had moved to the first rack when the blockage plate is installed on the rack top. Rack locations relative to air handler casts a negligible effect on the efficiency index, and it is comparatively more effective by sealing the trailing of the cold aisle. A smaller cold-aisle spacing helps to lower the temperature distribution, and an additional opening of the supplied vent will not help in removal of hot spot. Shutting off the grille in the center of cold aisle is also unable to fix the hot air recirculation and may even incur hot air reversal. The hot air reversal can be removed by adding additional blockage plate at the flow reversal section. Higher supplied air flow rate also improves the efficiency index considerably.

Impact of Tile Design on the Thermal Performance of Open and Enclosed Aisles

2018 ◽  
Vol 140 (1) ◽  
Author(s):  
Sadegh Khalili ◽  
Mohammad I. Tradat ◽  
Kourosh Nemati ◽  
Mark Seymour ◽  
Bahgat Sammakia
Keyword(s):  
Thermal Performance ◽  
Inlet Temperature ◽  
Open Area ◽  
Cfd Simulations ◽  
Physical Separation ◽  
Hot Air ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact ◽  
Lower Noise

In raised floor data centers, tiles with high open area ratio or complex understructure are used to fulfill the demand of today's high-density computing. Using more open tiles reduces the pressure drop across the raised floor with the potential advantages of increased airflow and lower noise. However, it introduces the disadvantage of increased nonuniformity of airflow distribution. In addition, there are various tile designs available on the market with different opening shapes or understructures. Furthermore, a physical separation of cold and hot aisles (containment) has been introduced to minimize the mixing of cold and hot air. In this study, three types of floor tiles with different open area, opening geometry, and understructure are considered. Experimentally validated detail models of tiles were implemented in computational fluid dynamics (CFD) simulations to address the impact of tile design on the cooling of information technology (IT) equipment in both open and enclosed aisle configurations. Also, impacts of under-cabinet leakage on the IT equipment inlet temperature in the provisioned and under-provisioned scenarios are studied. In addition, a predictive equation for the critical under-provisioning point that can lead to a no-flow condition in IT equipment with weaker airflow systems is presented. Finally, the impact of tile design on thermal performance in a partially enclosed aisle with entrance doors is studied and discussed.

scholarly journals Thermal Performance Evaluation of a Data Center Cooling System under Fault Conditions

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2996 ◽  
Author(s):  
Jinkyun Cho ◽  
Beungyong Park ◽  
Yongdae Jeong
Keyword(s):  
Water Supply ◽  
Thermal Performance ◽  
Data Center ◽  
Temperature Increase ◽  
Data Centers ◽  
Cooling System ◽  
Backup System ◽  
Air Supply ◽  
Chilled Water ◽  
Rapid Temperature

If a data center experiences a system outage or fault conditions, it becomes difficult to provide a stable and continuous information technology (IT) service. Therefore, it is critical to design and implement a backup system so that stability can be maintained even in emergency (unforeseen) situations. In this study, an actual 20 MW data center project was analyzed to evaluate the thermal performance of an IT server room during a cooling system outage under six fault conditions. In addition, a method of organizing and systematically managing operational stability and energy efficiency verification was identified for data center construction in accordance with the commissioning process. Up to a chilled water supply temperature of 17 °C and a computer room air handling unit air supply temperature of 24 °C, the temperature of the air flowing into the IT server room fell into the allowable range specified by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers standard (18–27 °C). It was possible to perform allowable operations for approximately 320 s after cooling system outage. Starting at a chilled water supply temperature of 18 °C and an air supply temperature of 25 °C, a rapid temperature increase occurred, which is a serious cause of IT equipment failure. Due to the use of cold aisle containment and designs with relatively high chilled water and air supply temperatures, there is a high possibility that a rapid temperature increase inside an IT server room will occur during a cooling system outage. Thus, the backup system must be activated within 300 s. It is essential to understand the operational characteristics of data centers and design optimal cooling systems to ensure the reliability of high-density data centers. In particular, it is necessary to consider these physical results and to perform an integrated review of the time required for emergency cooling equipment to operate as well as the backup system availability time.

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.

Effects of Servers' Rack Location and Power Loading Configurations on the Thermal Management of Data Center Racks' Array

2017 ◽  
Vol 9 (4) ◽  
Author(s):  
S. A. Nada ◽  
K. E. Elfeky
Keyword(s):  
Energy Efficiency ◽  
Thermal Management ◽  
Thermal Performance ◽  
Data Center ◽  
Real Data ◽  
Heat Index ◽  
Power Loading ◽  
And Performance ◽  
High Level ◽  
Power Densities

Effects of server/rack locations and server loading configurations on the thermal performance of data center racks' array are experimentally investigated using a scaled physical model simulating real data. Front and rear rack temperatures profiles, server temperatures, and performance indices supply/return heat index (SHI/RHI) are used to evaluate the thermal management of the racks' array. The results showed that (i) servers located in high level rack cabinet have the worst thermal performance, (ii) middle racks of the rack row showed optimum thermal performance and energy efficiency, and (iii) locating the servers of high power densities in the middle of the racks row improves the thermal performance and energy efficiency of the racks array.

scholarly journals Facing Boldly the Scourge of Praedial Larceny on Food Production in the Caribbean

2018 ◽  
Vol 25 (4) ◽  
pp. 52-62
Author(s):  
Wayne G. Ganpat ◽  
Wendy-Ann P Isaac
Keyword(s):  
Food Security ◽  
Food Production ◽  
Hot Spot ◽  
Economic Loss ◽  
Caribbean Region ◽  
Group Discussions ◽  
Farming Communities ◽  
Spot Area ◽  
The Caribbean ◽  
The Impact

Agricultural crimes or farm theft, commonly referred to as praedial larceny throughout the Caribbean, impacts significantly on food security through high levels of economic loss. This paper provides an overview of praedial larceny worldwide, losses in the Caribbean region and some evidence from Trinidad and Tobago where the situation is prevalent. The study was guided by the routine activities theory; identifying the types of criminal acts perpetrated, the level of risks posed to farmers and a special emphasis on the concept of guardianship. Data from group discussions and interviews conducted among farmers in two major areas in Trinidad representing different terrain (flat and hilly areas) and an acknowledged ‘hot spot’ area. The findings show that praedial larceny is no respecter of farmers, farming communities, type of crops, location or farmers’ economic circumstances. Finally, the paper reports on initiatives around the region and suggests other mechanisms which can be introduced to reduce the impact of praedial larceny on food security.

scholarly journals Validation and Optimization of Heat and Mass Transfer Model for Mushroom Convection Drying

2021 ◽  
Vol 293 ◽  
pp. 03011
Author(s):  
Huimin Shan ◽  
Kongqing Li
Keyword(s):  
Resistance Coefficient ◽  
Transfer Model ◽  
Hot Air Drying ◽  
Drying Time ◽  
Simulation Accuracy ◽  
Hot Air ◽  
Air Supply ◽  
Computational Fluid Dynamics Cfd ◽  
Drying System ◽  
Good Agreement

In order to solve the problems of time consuming, energy consumption and low simulation accuracy in the hot air-drying system of food drying. Using computational fluid dynamics (CFD) to simulate the drying process of mushrooms can provide a reference for its technology research and development (R&D). The porous media approach was used to model the flow resistance offered by the mushroom. The resistance coefficient and porosity were determined through the experiments. Different air supply ways (wind speed, temperature, fresh air volume, reverse air supply period) were simulated and two optimize ways were suggested according the shortest possible drying time. The simulation results are in good agreement with the experimental results. The air supply way of periodic with reverse (SMPR), which means timed alternate the direction of air flow, or the way of mix in fresh air intermittently can effectively shorten the drying time. Considering comprehensively, the optimal air supply way was the mix in fresh air intermittently with fresh air accounts for 30% or SMPR with the period of 2h under the condition of the hot air temperature of 55°C and wind velocity of 0.6m/s.

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.

scholarly journals Numerical Assessment of Earth to Air Heat Exchanger with Variable Humidity Conditions in Greenhouses

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1368
Author(s):  
Di Qi ◽  
Chuangyao Zhao ◽  
Shixiong Li ◽  
Ran Chen ◽  
Angui Li
Keyword(s):  
Heat Exchanger ◽  
Relative Humidity ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Energy Savings ◽  
Volume Flow Rate ◽  
Fluid Dynamic ◽  
Small Diameter ◽  
The Earth ◽  
The Impact

Earth to air heat exchangers are widely utilized to cool or heat passive buildings for energy savings. They often need to deal with high humidity air conditions, especially in the greenhouse due to plant transpiration, and the condensation phenomenon is frequently observed during the cooling process. To evaluate the effect of humidity and condensation on thermal performance, a three dimensional computational fluid dynamic (3D-CFD) model was developed. The distribution of relative humidity in each pipe was investigated, and the impact of inlet air relative humidity on the integrated performance of the earth to air heat exchanger was discussed. The effects of inlet air temperature and volume flow rate were also analyzed. Moreover, the influence of the heat exchanger configurations on the performance of the air condensation was researched. The results indicated that condensation had few effects on the airflow distribution uniformity of the earth to air heat exchanger, while it acted observably on the thermal performance. In addition, humid air in a small diameter pipe tended to condense more easily. Humidity and condensation should be taken into consideration for the design of earth to air heat exchangers in greenhouses during engineering applications.

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