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.

Review on Cooling System Energy Consumption in Internet Data Centers

2016 ◽  
Vol 24 (04) ◽  
pp. 1630008 ◽  
Author(s):  
Kofi Owura Amoabeng ◽  
Jong Min Choi
Keyword(s):  
Energy Consumption ◽  
Data Center ◽  
Energy Demand ◽  
Data Centers ◽  
Cooling System ◽  
High Heat ◽  
Total Energy Consumption ◽  
It Industry ◽  
Public And Private ◽  
Conventional Cooling

Due to the advancement of the telecommunication and information technology (IT) industry, internet data centers (IDCs) have become widespread in the public and private sectors. As such, energy demand in the center has also become increasingly prominent. Several technologies on energy management have been studied to determine the options available to minimize the energy required to operate the data center as well as reduce greenhouse gas emissions. The cooling system is required to remove the high heat dissipated by the IT electronic components especially the servers in order to ensure safe and reliable working condition. However, it utilizes more than one-third of the total energy consumption in the data center. In this study, the energy efficiency technologies that are usually applied to cooling systems in data centers were reviewed. The aim is to find out the strategies that will reduce the energy consumption of the cooling system since the cooling demand in data center is all year round. Prior to that, the performance metric tool that is mostly used in analyzing data center efficiency was discussed. The conventional cooling system technologies that are utilized in data centers were also provided. Lastly, innovative cooling technologies for future solutions in data centers were discussed.

Design of Passive Two-Phase Thermosyphons for Server Cooling

2019 ◽  
Author(s):  
Raffaele L. Amalfi ◽  
Jackson B. Marcinichen ◽  
John R. Thome ◽  
Filippo Cataldo
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Energy Efficient ◽  
High Efficiency ◽  
Cooling System ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Annual Growth Rate ◽  
Total Energy Consumption ◽  
Two Phase

Abstract The main objective of this paper is to utilize an improved version of the simulator presented at InterPACK 2017 to design a thermosyphon system for energy-efficient heat removal from 2-U servers used in high-power datacenters. Currently, between 25% and 45% of the total energy consumption of a datacenter (this number does not include the energy required to drive the fans at the server-level) is dedicated to cooling, and with a predicted annual growth rate of about 15% (or higher) coupled with the plan of building numerous new datacenters to handle the “big data” storage and processing demands of emerging 5G networks, artificial intelligence, electrical vehicles, etc., the development of novel, high efficiency cooling technologies becomes extremely important for curbing the use of energy in datacenters. Notably, going from air cooling to two-phase cooling, not only enables the possibility to handle the ever higher heat fluxes and heat loads of new servers, but it also provides an energy-efficient solution to be implemented for all servers of a datacenter to reduce the total energy consumption of the entire cooling system. In that light, a pseudo-chip with a footprint area of 4 × 4 cm2 and a maximum power dissipation of 300 W (corresponding heat flux of about 19 W/cm2), will be assumed as a target design for our novel thermosyphon-based cooling system. The simulator will be first validated against an independent database and then used to find the optimal design of the chip’s thermosyphon. The results demonstrate the capability of this simulator to model all of the thermosyphon’s components (evaporator, condenser, riser and downcomer) together with overall thermal performance and creation of operational maps. Additionally, the simulator is used here to design two types of passive two-phase systems, an air- and a liquid-cooled thermosyphon, which will be compared in terms of thermal-hydraulic performance. Finally, the simulator will be used to perform a sensitivity analysis on the secondary coolant side conditions (inlet temperature and mass flow rate) to evaluate their effect on the system performance.

scholarly journals Modeling and optimization of a chilled-water cooling system with multiple chillers

2020 ◽  
pp. 328-328
Author(s):  
Jiamin Du ◽  
Shuhong Li ◽  
Xinmei Li
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Cooling System ◽  
Support Vector ◽  
Water Cooling ◽  
Parallel Operation ◽  
Total Energy Consumption ◽  
Modeling And Optimization ◽  
Chilled Water ◽  
Water Cooling System

In order to reduce energy consumption of the centralized chilled-water cooling system in large buildings, a dynamic control strategy was proposed for cooling plants by modeling and optimization. Combined with the chilled water flow model, this paper analyzed the parallel operation characteristics of the chillers and takes the load distribution as one of the control parameters. Based on the measured data of a typical cooling system that has undergone preliminary energy-saving transformation, the residual neural network (ResNet) is applied to model the relationship among energy consumption, controllable parameters and environmental parameters, and the ResNet outperforms multi-layer perceptron (MLP) and support vector regression (SVR). To minimize the total energy consumption, the gray wolf optimizer (GWO) was introduced to optimize the controllable variables of the cooling system. Compared with the energy consumption before optimization, the simulation energy consumption after optimization decreased 10.45% on average, while the energy saving rate is only 7.9% with equal chilled water supply temperature of parallel chillers.

Rack-Level Study of Hybrid Cooled Servers Using Warm Water Cooling With Variable Pumping for Centralized Coolant System

2018 ◽  
Author(s):  
Manasa Sahini ◽  
Chinmay Kshirsagar ◽  
Patrick McGinn ◽  
Dereje Agonafer
Keyword(s):  
Data Center ◽  
Data Centers ◽  
Warm Water ◽  
Cooling Power ◽  
Water Cooling ◽  
Liquid Cooling ◽  
Web Servers ◽  
Pump Speed ◽  
Viable Solution ◽  
In Series

As global demand for data centers grows, so does the size and load placed on data centers, leading constraints on power and space available to the operator. Cooling power consumption is a major part of the data center energy usage. Liquid cooling technology has emerged as a viable solution in the process of optimization of the energy consumed per performance unit. In this data center rack level evaluation, 2OU (Open U) hybrid (liquid+air) cooled web servers are tested to observe the effects of warm water cooling on the server component temperatures, IT power and cooling power. The study discusses the importance of variable speed pumping in a centralized coolant configuration system. The cooling setup includes a mini rack capable of housing up to eleven hybrid cooled web servers and two heat exchangers that exhaust the heat dissipated from the servers to the environment (the test rig data center room). The centralized configuration has two redundant pumps placed in series with heat exchanger at the rack. Each server is equipped with two passive (i.e. no active pump) cold plates for cooling the CPUs while rests of the components are air cooled. Synthetic stress load has been generated on each server using stress-testing tools. Pumps in the servers are separately powered using an external power supply. The pump speed is proportional to the voltage across the armature [1]. The pump rpm has been recorded with input voltages ranging from 11V to 17V. The servers are tested for higher inlet temperatures ranging from 25°C to 45°C which falls within the ASHRAE liquid cooled envelope W4 [2]. Variable pumping has been achieved by using different input voltages at respective inlet temperatures.

Dynamic Control of Airflow Balance in Data Centers

2019 ◽  
Author(s):  
Stephen Paul Linder ◽  
Jim Van Gilder ◽  
Yan Zhang ◽  
Enda Barrett
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Pressure Sensor ◽  
Data Center ◽  
Data Centers ◽  
Dynamic Control ◽  
Air Pressure ◽  
Cooling Efficiency ◽  
Total Energy Consumption ◽  
Flow Network

Abstract Efficient cooling of data center infrastructure is an important way to reduce total energy consumption. Containment, with separation of hot and cold airflows has allowed significant increase in efficiencies. However, balancing the airflow, so that IT equipment in an aisle only receives the cooling airflow that that aisle needs is still often not done. We propose a new architecture where IT racks are clustered together with shared hot aisles ducted to a common ceiling plenum. Each aisle has an actively controlled damper used to balance the airflow to the cooling infrastructure. Using a differential air pressure sensor in each aisle and an algorithm designed to balance the flow network, we minimize the cooling airflow and maximize cooling efficiency.

Energy Modeling of Air-Cooled Data Centers: Part I—The Optimization of Enclosed Aisle Configurations

2011 ◽  
Author(s):  
Dustin W. Demetriou ◽  
H. Ezzat Khalifa
Keyword(s):  
Energy Consumption ◽  
Power Consumption ◽  
Temperature Rise ◽  
Data Center ◽  
Data Centers ◽  
Total Power ◽  
Optimum Operating ◽  
Cooling Power ◽  
Inlet Temperature ◽  
Total Energy Consumption

The work presented in this paper describes a simplified thermodynamic model that can be used for exploring optimization possibilities in air-cooled data centers. The model is used to parametrically evaluate the total energy consumption of the data center cooling infrastructure for data centers that utilize aisle containment. The analysis highlights the importance of reducing the total power required for moving the air within the CRACs, the plenum, and the servers, rather than focusing primarily or exclusively on reducing the refrigeration system’s power consumption and shows the benefits of bypass recirculation in enclosed aisle configurations. The analysis shows a potential for as much as a 57% savings in cooling infrastructure energy consumption by utilizing an optimized enclosed aisle configuration with bypass recirculation, instead of a traditional enclosed aisle, where all the data center exhaust is forced to flow through the computer room air conditioners (CRACs), for racks with a modest temperature rise (∼10°C). However, for racks with larger temperature rise (> ∼20°C), the saving are less than 5%. Furthermore, for servers whose fan speed (flow rate) varies as a function of inlet temperature, the analysis shows that the optimum operating regime for enclosed aisle data centers falls within a very narrow band and that power reductions are possible by lowering the uniform server inlet temperature in the enclosed aisle from 27°C to 22°C. However, the optimum CRAC exit temperature over the 22-to-27°C range of enclosed cold aisle temperature falls between ∼16 and 20°C because a significant reduction in the power consumption is possible through the use of bypass recirculation. Without bypass recirculation, the power consumption for a server inlet temperature of 22°C enclosed aisle case with a server temperature rise of 10°C would be a whopping 43% higher than with bypass recirculation. It is worth noting that, without bypass recirculation maintaining the enclosed cold aisle at 22°C instead of 27°C would reduce power consumption by 48%. It is also shown that enclosing the aisles together with bypass recirculation (when beneficial) also reduces the dependence of the optimum cooling power on server temperature rise.

scholarly journals Energy analysis using carrier HAP program and Deep Lake Water Cooling (DLWC) feasibility analysis for Ryerson University

2021 ◽  
Author(s):  
Md. Ziaur Rahman
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Lake Water ◽  
Building Energy ◽  
Energy Simulation ◽  
Base Case ◽  
Water Cooling ◽  
Ghg Emission ◽  
Deep Lake ◽  
Total Energy Consumption

The objective of this project is to determine the total annual energy summary in terms of cost and Greenhouse Gas (GHG) emission of 16 buildings at Ryerson University (RU). In addition, the Deep Lake Water Cooling (DLWC) feasibility analysis of RU is another objective of this project in terms of total energy consumption and amount of gas emission reduction. The total audit area of RU was 86% of the total campus area. Building energy simulation program, Carrier HAP (Hourly Analysis Program), has been used to make an integrated evaluation of building energy consumption. An energy simulation involves hour-by-hour calculations for all 8,760 hours in a year. In this project, an energy audit was conducted for the 16 existing buildings to establish the base case model, "Ryerson University", to determine its annual energy consumption across all usage. There are two sources of energy used at RU. Electricity uses for lighting, plug load, miscellaneous and cooling, and remote steam is used for cooling and heating. For the base case model, total energy consumption was 251 TJ. To reduce the total energy consumption of the base case model, HVAC systems were investigated to analyze their energy-based performance and impact on the GHG emission. There is no Heat Recovery Ventilation (HRV) system coming from the investigation of HVAC system. The sensitivity analysis was conducted using HRV system with air system. By using HRV system with air system, total of 5.6% energy would be saved for cooling and 76% energy would be saved for heating of RU. The energy intensity was determined to be 1.04 GJ/m² only for 16 buildings of RU and comparatively it is lower than other universities in Canada which have a range of 1.64 GJ/m² to 2.26 GJ/m². In the DLWC system, cool lake water at 4°C was used for building air conditioning. To reduce the cooling energy costs, DLWC system was considered as an alternative chilled water source. The Rogers Business Building (RBB) already has DLWC system. For DLWC system, chilled water was served by Enwave to the RBB. According to base case analysis of the RBB with conventional chillers, the electricity consumption was 924594 kWh for RBB due to chillers. With the implementation of DLWC system for the rest of the 15 buildings, total energy saving due to cooling would be 89.2% and GHG emission reduction would be 89% for CO₂, 70% for NOx and 70.4% for SOx due to elimination of chillers.

New Thermal Management Systems for Data Centers

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Mayumi Ouchi ◽  
Yoshiyuki Abe ◽  
Masato Fukagaya ◽  
Takashi Kitagawa ◽  
Haruhiko Ohta ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Single Phase ◽  
Data Centers ◽  
Cooling System ◽  
Heat Pipes ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Two Phase ◽  
Cooling Jacket ◽  
Cooling Methods

Energy consumption in data centers has seen a drastic increase in recent years. In data centers, server racks are cooled down in an indirect way by air-conditioning systems installed to cool the entire server room. This air cooling method is inefficient as information technology (IT) equipment is insufficiently cooled down, whereas the room is overcooled. The development of countermeasures for heat generated by IT equipment is one of the urgent tasks to be accomplished. We, therefore, proposed new liquid cooling systems in which IT equipment is cooled down directly and exhaust heat is not radiated into the server room. Three cooling methods have been developed simultaneously. Two of them involve direct cooling; a cooling jacket is directly attached to the heat source (or CPU in this case) and a single-phase heat exchanger or a two-phase heat exchanger is used as the cooling jacket. The other method involves indirect cooling; heat generated by CPU is transported to the outside of the chassis through flat heat pipes and the condensation sections of the heat pipes are cooled down by coolant with liquid manifold. Verification tests have been conducted by using commercial server racks to which these cooling methods are applied while investigating five R&D components that constitute our liquid cooling systems: the single-phase heat exchanger, the two-phase heat exchanger, high performance flat heat pipes, nanofluid technology, and the plug-in connector. As a result, a 44–53% reduction in energy consumption of cooling facilities with the single-phase cooling system and a 42–50% reduction with the flat heat pipe cooling system were realized compared with conventional air cooling system.

Analysis of Running Energy Consumption of Fresh Air Cooling Systems

Solar Energy ◽  
2005 ◽  
Author(s):  
Jianing Zhao ◽  
Jun Guo ◽  
Weimeng Sun
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Cooling System ◽  
Air Cooling ◽  
Total Energy Consumption ◽  
Cooling Systems ◽  
Variable Air Volume ◽  
Air Volume ◽  
Air System ◽  
Different Seasons

Utilization of renewable energy becomes more and more attractive and crucial for sustainable buildings. A cooling system, using outdoor fresh air and combining with the conventional all-air system or running along during different seasons, is discussed in this study. Running energy consumption of this system is analyzed by a mathematical model using the Genetic Algorithm (GA) combined with the traditional Lagrange method. To evaluate and apply this new system, energy consumption of the chiller unit, water and air sub-systems, as well as the total energy consumption of such a system is compared with that of the conventional all-air system. Consequently, the total energy consumption is selected as the criterion of energy efficiency. The results show that the cooling system bears considerably energy efficient, and that it reduces energy consumption at least 14% and 12%, compared with the constant air volume and variable air volume system, respectively.

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.

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