Numerical Modeling of Perforated Tile Flow Distribution in a Raised-Floor Data Center

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Emad Samadiani ◽  
Jeffrey Rambo ◽  
Yogendra Joshi
Keyword(s):  
Numerical Modeling ◽  
Flow Rate ◽  
Data Center ◽  
Air Conditioning ◽  
Flow Distribution ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Average Change ◽  
Tile Flow ◽  
Operating Points

This paper is centered on quantifying the effect of computer room and computer room air conditioning (CRAC) unit modeling on the perforated tile flow distribution in a representative raised-floor data center. Also, this study quantifies the effect of plenum pipes and perforated tile porosity on the operating points of the CRAC blowers, total CRAC air flow rate, and its distribution. It is concluded that modeling the computer room, the CRAC units, and/or the plenum pipes could make an average change of up to 17% in the tile flow rates with a maximum of up to 135% for the facility with 56% open tiles while the average and maximum changes for the facility with 25% open tiles are 6% and 60%, respectively.

Numerical Modeling of Perforated Tile Flow Distribution in a Raised-Floor Data Center

2007 ◽  
Author(s):  
Emad Samadiani ◽  
Jeffrey Rambo ◽  
Yogendra Joshi
Keyword(s):  
Numerical Modeling ◽  
Flow Rate ◽  
Data Center ◽  
Air Conditioning ◽  
Air Flow ◽  
Flow Distribution ◽  
Air Flow Rate ◽  
Tile Flow ◽  
Operating Points

This paper is centered on quantifying the effect of computer room and computer room air conditioning (CRAC) unit modeling on the perforated tile flow distribution in a representative raised-floor data center. Also, this study quantifies the effect of plenum pipes and perforated tile porosity on the operating points of the CRAC blowers, total CRAC air flow rate, and its distribution. It is concluded that modeling the computer room, CRAC units, and/or the plenum pipes could change the tile flow distribution by up to 60% for the facility with 25% open perforated tiles and up to 135% for the facility with 56% open perforated tiles.

Load Capacity and Thermal Efficiency Optimization of a Research Data Center Using Computational Modeling

2015 ◽  
Author(s):  
Joseph R. H. Schaadt ◽  
Kamran Fouladi ◽  
Aaron P. Wemhoff ◽  
Joseph G. Pigeon
Keyword(s):  
Flow Rate ◽  
Data Center ◽  
Air Conditioning ◽  
Data Centers ◽  
Load Capacity ◽  
Research Data ◽  
Optimal Operating ◽  
Cold Aisle Containment ◽  
Operating Points ◽  
The Ideal

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.

Model-Based Analysis of Transient Behavior of Large Scale CFB Boilers

2003 ◽  
Author(s):  
Ari Kettunen ◽  
Timo Hyppa¨nen ◽  
Ari-Pekka Kirkinen ◽  
Esa Maikkola
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Air Flow ◽  
Model Parameters ◽  
Air Flow Rate ◽  
Process Data ◽  
Cfb Boiler ◽  
Flow Rates ◽  
Load Change ◽  
Secondary Air

The main objective of this study was to investigate the load change capability and effect of the individual control variables, such as fuel, primary air and secondary air flow rates, on the dynamics of large-scale CFB boilers. The dynamics of the CFB process were examined by dynamic process tests and by simulation studies. A multi-faceted set of transient process tests were performed at a commercial 235 MWe CFB unit. Fuel reactivity and interaction between gas flow rates, solid concentration profiles and heat transfer were studied by step changes of the following controllable variables: fuel feed rate, primary air flow rate, secondary air flow rate and primary to secondary air flow ratio. Load change performance was tested using two different types of tests: open and closed loop load changes. A tailored dynamic simulator for the CFB boiler was built and fine-tuned by determining the model parameters and by validating the models of each process component against measured process data of the transient test program. The know-how about the boiler dynamics obtained from the model analysis and the developed CFB simulator were utilized in designing the control systems of three new 262 MWe CFB units, which are now under construction. Further, the simulator was applied for the control system development and transient analysis of the supercritical OTU CFB boiler.

Effects of Inlet Mass Flow Distribution and Magnitude on Reactant Distribution for PEM Fuel Cells

2005 ◽  
Vol 3 (1) ◽  
pp. 45-50 ◽  
Author(s):  
M. McGarry ◽  
L. Grega
Keyword(s):  
Fuel Cell ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Separation ◽  
Flow Distribution ◽  
Pem Fuel Cells ◽  
Local Flow ◽  
Flow Rates ◽  
Large Active Area ◽  
Mass Flow Rates

The mass flow distribution and local flow structures that lead to areas of reactant starvation are explored for a small power large active area PEM fuel cell. A numerical model was created to examine the flow distribution for three different inlet profiles; blunt, partially developed, and fully developed. The different inlet profiles represent the various distances between the blower and the inlet to the fuel cell and the state of flow development. The partially and fully developed inlet profiles were found to have the largest percentage of cells that are deficient, 20% at a flow rate of 6.05 g/s. Three different inlet mass flow rates (stoichs) were also examined for each inlet profile. The largest percent of cells deficient in reactants is 27% and occurs at the highest flow rate of 9.1 g/s (3 stoichs) for the partially and fully developed turbulent profiles. In addition to the uneven flow distribution, flow separation occurs in the front four channels for the blunt inlet profile at all flow rates examined. These areas of flow separation lead to localized reactant deficient areas within a channel.

Energy Flow in the Information Technology Stack: Introducing the Coefficient of Performance of the Ensemble

2006 ◽  
Author(s):  
Chandrakant D. Patel ◽  
Ratnesh K. Sharma ◽  
Cullen E. Bash ◽  
Monem H. Beitelmal
Keyword(s):  
Information Technology ◽  
Data Center ◽  
Air Conditioning ◽  
Cooling Tower ◽  
Heat Removal ◽  
Flow Distribution ◽  
Coefficient Of Performance ◽  
Dynamics Modeling ◽  
Smart Data ◽  
The Cost

The information technology industry is in the midst of a transformation to lower the cost of operation through consolidation and better utilization of critical data center resources. Successful consolidation necessitates increasing utilization of capital intensive "always-on" data center infrastructure, and reducing the recurring cost of power. A need exists, therefore for an end to end physical model that can be used to design and manage dense data centers and determine the cost of operating a data center. The chip core to the cooling tower model must capture the power levels and thermo-fluids behavior of chips, systems, aggregation of systems in racks, rows of racks, room flow distribution, air conditioning equipment, hydronics, vapor compression systems, pumps and heat exchangers. Earlier work has outlined the foundation for creation of a "smart" data center through use of flexible cooling resources and a distributed sensing and control system that can provision the cooling resources based on the need. This paper shows a common thermodynamic platform which serves as an evaluation and basis for policy based control engine for such a "smart" data center with much broader reach - from chip core to the cooling tower. Computational Fluid Dynamics modeling is performed to determine the computer room air conditioning utilization for a given distribution of heat load and cooling resources in a production data center. Coefficient of performance (COP) of the computer room air conditioning units, based on the level of utilization, is used with COP of other cooling resources in the stack to determine the COP of the ensemble. The ensemble COP represents an overall measure of the performance of the heat removal stack in a data center.

Numerical and experimental investigation on the air flow characteristics of heating, ventilation, and air-conditioning module for a small electric vehicle

2019 ◽  
Vol 234 (6) ◽  
pp. 1597-1609
Author(s):  
Kang Li ◽  
Hao Gao ◽  
Peng Jia ◽  
Lin Su ◽  
Yidong Fang ◽  
...  
Keyword(s):  
Heat Pump ◽  
Flow Rate ◽  
Air Conditioning ◽  
Air Flow ◽  
Flow Characteristics ◽  
Cold Climate ◽  
Airflow Rate ◽  
Positive Temperature ◽  
Air Flow Rate ◽  
Pump System

In electrical vehicles, replacing positive temperature coefficient heater as heat source with an air source heat pump could improve the driving range and decrease energy consumption in cold climate. Design of the heating, ventilation, and air-conditioning module for heat pump system has a significant influence on its performance in each working mode. A newly designed heat pump heating, ventilation, and air-conditioning module was introduced in this paper. The air flow characteristics of the heat pump heating, ventilation, and air-conditioning module in four working modes were analyzed, and the air flow rate and wind resistance were obtained by numerical simulation. Experiments were also conducted for validating its airflow rate in each working mode. Results of these experiments show that some unfavorable phenomena such as flow maldistribution and vortex inside the heat pump heating, ventilation, and air-conditioning module exist, which could lead to insufficient utilization of the heat exchange area of heat exchangers and the generation of aerodynamic noise. Furthermore, the air flow rate of the original heating, ventilation, and air-conditioning module was also measured for comparison, and the designed heat pump heating, ventilation, and air-conditioning module shows nearly 15–20% decrease in each working mode.

Raised Floor Hybrid Cooled Data Center: Effect on Rack Inlet Air Temperatures When In Row Cooling Units are Installed Between the Racks

2015 ◽  
Author(s):  
Tianyi Gao ◽  
James Geer ◽  
Russell Tipton ◽  
Bruce Murray ◽  
Bahgat G. Sammakia ◽  
...  
Keyword(s):  
Flow Rate ◽  
Data Center ◽  
Heat Load ◽  
Data Centers ◽  
Cooling System ◽  
Air Flow ◽  
Inlet Temperature ◽  
Air Flow Rate ◽  
Air Temperatures ◽  
Cooling Unit

The heat dissipated by high performance IT equipment such as servers and switches in data centers is increasing rapidly, which makes the thermal management even more challenging. IT equipment is typically designed to operate at a rack inlet air temperature ranging between 10 °C and 35 °C. The newest published environmental standards for operating IT equipment proposed by ASHARE specify a long term recommended dry bulb IT air inlet temperature range as 18°C to 27°C. In terms of the short term specification, the largest allowable inlet temperature range to operate at is between 5°C and 45°C. Failure in maintaining these specifications will lead to significantly detrimental impacts to the performance and reliability of these electronic devices. Thus, understanding the cooling system is of paramount importance for the design and operation of data centers. In this paper, a hybrid cooling system is numerically modeled and investigated. The numerical modeling is conducted using a commercial computational fluid dynamics (CFD) code. The hybrid cooling strategy is specified by mounting the in row cooling units between the server racks to assist the raised floor air cooling. The effect of several input variables, including rack heat load and heat density, rack air flow rate, in row cooling unit operating cooling fluid flow rate and temperature, in row coil effectiveness, centralized cooling unit supply air flow rate, non-uniformity in rack heat load, and raised floor height are studied parametrically. Their detailed effects on the rack inlet air temperatures and the in row cooler performance are presented. The modeling results and corresponding analyses are used to develop general installation and operation guidance for the in row cooler strategy of a data center.

Effect of Supply Air Temperature on Rack Cooling in a High Density Raised Floor Data Center Facility

2011 ◽  
Author(s):  
Pramod Kumar ◽  
Vikneshan Sundaralingam ◽  
Yogendra Joshi ◽  
Michael K. Patterson ◽  
Robin Steinbrecher ◽  
...  
Keyword(s):  
Flow Field ◽  
Air Temperature ◽  
Data Center ◽  
Flow Distribution ◽  
High Density ◽  
Flow Measurements ◽  
Air Inlet ◽  
Air Temperatures ◽  
Tile Flow ◽  
Temperature Maps

In this paper we experimentally investigate the effect of supply air temperature on rack cooling in a high density raised floor data center facility. A series of experiments are performed on a 42 U (1-U = 4.45 cm) rack populated with 1-U servers. Desired rack heat loads are achieved by managing the distribution of server compute load within the rack. During the present experiments, temperatures at various locations in the hot and cold aisle corresponding to the rack air inlet and outlet are recorded. The temperatures are measured using a grid consisting of 256 thermocouples. The temperature measurements are further complimented with the flow field at the rack inlet. Particle Image Velocimetry (PIV) technique is used to capture the flow field at the rack inlet. The temperature maps in concert with the PIV flow field help in quantifying the rack cooling effectiveness. The temperature and flow measurements are measured for various cases by altering the supply air temperatures and perforated tile flow rates. The results are analyzed and compared with the ASHRARE recommended guidelines to arrive at the optimum supply air temperature. A perceptible change in the temperature and flow distribution is observed for the six cases investigated.

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