High Performance Loop Heat Pipe With Flat Evaporator for Energy-Saving Cooling Systems of Supercomputers

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Zhi Hu Xue ◽  
Wei Qu ◽  
Ming Hui Xie
Keyword(s):  
Heat Load ◽  
High Performance ◽  
Operating Temperature ◽  
Cooling Water ◽  
Working Fluid ◽  
Air Cooling ◽  
Water Cooling ◽  
Test Results ◽  
Central Processing ◽  
Flat Evaporator

Abstract Two high performance loop heat pipes (LHPs) are developed for direct cooling of the chips in supercomputer. The two LHPs using flat evaporator are: one called water-cooling LHP and another one called air-cooling LHP. The working fluid of LHP is ammonia. The water-cooling LHP can work well at a heat load up to 663 W and air-cooling LHP can work well at a heat load up to 513 W. The two LHPs applying to the real computer servers are realized and tested. The server test results with water-cooling LHP have shown that the operating temperature of central processing units (CPUs) can be controlled to about 67 °C to ensure the reliable operating and acceptable level for electronic chips, even at condenser-cooling water temperature of 40 °C with low water flowrate of 0.055 m3/h. The server test results with air-cooling LHP have shown that the operating temperature of CPUs can be controlled to about 51 °C even at condenser-cooling wind temperature of 30 °C with wind flowrate of 41.88 m3/h.

Energy Efficiency Analyses and Comparison of Air and Water Cooled High Performance Servers

2009 ◽  
Author(s):  
Michael J. Ellsworth ◽  
Madhusudan K. Iyengar
Keyword(s):  
Energy Efficiency ◽  
Energy Consumption ◽  
Heat Load ◽  
High Performance ◽  
Energy Savings ◽  
Air Cooling ◽  
Water Cooling ◽  
Water Side ◽  
Comparable Performance ◽  
Facility Level

This paper presents a study that illustrates the energy efficiency benefits of using water cooling for server thermal management versus utilizing air-cooling for high performance server applications. In 2008 IBM introduced the water cooled Power 575 Supercomputing Node, which is packaged in a super-dense 2U (88.9 mm) form factor. A fully configured system can dissipate as much as 72 kW with 80% of the heat load going to water. A fully air cooled version of this system, developed by Hitachi, operates 3.5 GHz and dissipates 61 kW at the frame level. In this paper, numerical analyses is first carried to help provide a context for the data center air-conditioning energy consumption, necessary to cool comparable performance clusters for both the air and water cooled racks, respectively. The room level CFD calculations are then extended to the facility level, by including the energy consumption of the refrigeration chiller, the building and condenser water pumps, and the cooling towers. Recent innovations that enable the use of water side economizers as well as 100% water cooling of racks are also discussed. The results show that there can be as much as a 45% reduction in the facilities power to cool the water cooled system compared to the energy required for the air cooled equivalent. When 100% of the server heat load is transferred directly to the chilled water supplied to the racks, there can be a 50% energy savings compared to traditional air-cooling. Lastly, use of 100% water cooling in conjunction with water side economizers can yield more than 90% cooling energy savings compared to the air-cooled configurations.

scholarly journals Optimization of Cascade Cooling System Based on Lithium Bromide Refrigeration in the Polysilicon Industry

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1681
Author(s):  
Shutong Yang ◽  
Youlei Wang ◽  
Yufei Wang
Keyword(s):  
Annual Cost ◽  
Load Distribution ◽  
Heat Load ◽  
Waste Heat ◽  
Cooling System ◽  
Cooling Water ◽  
Total Annual Cost ◽  
Air Cooling ◽  
Water Cooling ◽  
Cooling Methods

Cascade cooling systems containing different cooling methods (e.g., air cooling, water cooling, refrigerating) are used to satisfy the cooling process of hot streams with large temperature spans. An effective cooling system can significantly save energy and costs. In a cascade cooling system, the heat load distribution between different cooling methods has great impacts on the capital cost and operation cost of the system, but the relative optimization method is not well established. In this work, a cascade cooling system containing waste heat recovery, air cooling, water cooling, absorption refrigeration, and compression refrigeration is proposed. The objective is to find the optimal heat load distribution between different cooling methods with the minimum total annual cost. Aspen Plus and MATLAB were combined to solve the established mathematical optimization model, and the genetic algorithm (GA) in MATLAB was adopted to solve the model. A case study in a polysilicon enterprise was used to illustrate the feasibility and economy of the cascade cooling system. Compared to the base case, which only includes air cooling, water cooling, and compression refrigeration, the cascade cooling system can reduce the total annual cost by USD 931,025·y−1 and save 7,800,820 kWh of electricity per year. It also can recover 3139 kW of low-grade waste heat, and generate and replace a cooling capacity of 2404 kW.

Operational Limitations of Heat Pipes With Silver-Water Nanofluids

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Lazarus Godson Asirvatham ◽  
Rajesh Nimmagadda ◽  
Somchai Wongwises
Keyword(s):  
Silver Nanoparticles ◽  
Heat Pipe ◽  
Heat Load ◽  
Operating Temperature ◽  
Particle Diameter ◽  
Heat Pipes ◽  
Working Fluid ◽  
Limit Value ◽  
Capillary Limit ◽  
Nanoparticles Concentration

The paper presents the enhancement in the operational limits (boiling, entrainment, sonic, viscous and capillary limits) of heat pipes using silver nanoparticles dispersed in de-ionized (DI) water. The tested nanoparticles concentration ranged from 0.003 vol. % to 0.009 vol. % with particle diameter of <100 nm. The nanofluid as working fluid enhances the effective thermal conductivity of heat pipe by 40%, 58%, and 70%, respectively, for volume concentrations of 0.003%, 0.006%, and 0.009%. For an input heat load of 60 W, the adiabatic vapor temperatures of nanofluid based heat pipes are reduced by 9 °C, 18 °C, and 20 °C, when compared with DI water. This reduction in the operating temperature enhances the thermophysical properties of working fluid and gives a change in the various operational limits of heat pipes. The use of silver nanoparticles with 0.009 vol. % concentration increases the capillary limit value of heat pipe by 54% when compared with DI water. This in turn improves the performance and operating range of the heat pipe.

Experimental and Numerical Study of the Effects of Asymmetric Micro Ratchets on Pool Boiling Performance

2013 ◽  
Author(s):  
Lance Brumfield ◽  
Sunggook Park
Keyword(s):  
High Performance ◽  
Numerical Study ◽  
Heated Surface ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Industrial Applications ◽  
Heat Fluxes ◽  
Working Fluid ◽  
High Heat Flux ◽  
Central Processing

Nucleate boiling is an attractive method for achieving high heat flux at low superheat temperatures. It is frequently used for industrial applications such as heat exchangers and is being considered to cool advanced central processing units (CPU) which produce heat fluxes on the order of 1 MW/m2 and are becoming increasingly less efficient to cool via forced conduction of air. The issues with implementing nucleate boiling as a cooling mechanism lies in the difficulty of quantifying the complex and numerous mechanisms which control the process. A comprehensive nucleate boiling model has yet to be formulated and will be required in order to safely and reliably cool high performance electronics. Spatially periodic systems with localized asymmetric surface structures (ratchets) can induce directed transport of matter (liquid/particles) in the absence of net force. It was hypothesized that ratchets may enhance pool boiling heat transfer by aiding in the removal of vapor which forms on the heated surface. Therefore, experiments on pool boiling using asymmetric micro ratchets of various geometries, with FC-72 as the working fluid, were investigated. Additionally, various numerical pool boiling simulations were performed using FLUENT to better understand the underlying physical principles behind pool boiling.

Thermodynamic Characterization of a Direct Water Cooled Server Rack Running Synthetic and Real High Performance Computing Work Loads

2015 ◽  
Author(s):  
Lynn Parnell ◽  
Garrison Vaughan ◽  
John Thompson ◽  
Daniel Duffy ◽  
Louis Capps ◽  
...  
Keyword(s):  
High Performance Computing ◽  
High Performance ◽  
Cooling Water ◽  
Air Cooling ◽  
Single Server ◽  
Worst Case ◽  
Flow Rates ◽  
Benchmark Tests ◽  
Consumption Change ◽  
Performance Computing

High performance computing server racks are being engineered to contain significantly more processing capability within the same computer room footprint year after year. The processor density within a single rack is becoming high enough that traditional, inefficient air-cooling of servers is inadequate to sustain HPC workloads. Experiments that characterize the performance of a direct water-cooled server rack in an operating HPC facility are described in this paper. Performance of the rack is reported for a range of cooling water inlet temperatures, flow rates and workloads that include actual and worst-case synthetic benchmarks. Power and temperature measurements of all processors and memory components in the rack were made while extended benchmark tests were conducted throughout the range of cooling variables allowed within an operational HPC facility. Synthetic benchmark results were compared with those obtained on a single server of the same design that had been characterized thermodynamically. Neither actual nor synthetic benchmark performances were affected during the course of the experiments, varying less than 0.13 percent. Power consumption change in the rack was minimal for the entire excursion of coolant temperatures and flow rates. Establishing the characteristics of such a highly energy efficient server rack in situ is critical to determine how the technology might be integrated into an existing heterogeneous, hybrid cooled computing facility — i.e., a facility that includes some servers that are air cooled as well as some that are direct water cooled.

Mathematical Simulation of a Solar Bi-Ejector Refrigeration System

Solar Energy ◽  
2006 ◽  
Author(s):  
Bo Zhang ◽  
Jianhua Dong ◽  
Shengqiang Shen
Keyword(s):  
Thermal Behavior ◽  
Mathematical Simulation ◽  
Heat Load ◽  
Cooling Water ◽  
Electricity Consumption ◽  
Working Fluid ◽  
Cooling Load ◽  
Refrigeration System ◽  
Simulation Results ◽  
Mechanical Circulation

This paper presents a mathematical simulation of the dynamic thermal behavior of an innovative solar bi-ejector refrigeration system with a capacity to produce cooling water. In the bi-ejector refrigeration system, the mechanical circulation pump is replaced by a vapor-liquid ejector, in order to further reduce the electricity consumption and reinforce the system feasibility. Freon R123 is the working fluid at condensing temperature of 30°C generating temperature of 85°C and evaporating temperature of 8°C The generator heat load is 10kW and an obtained evaporator cooling load is around 3kW. The whole year simulation results are presented.

Design of Cooling Water Scheme of Gas Compressing Station in West-to-East Gas Pipeline

2014 ◽  
Vol 577 ◽  
pp. 580-583
Author(s):  
Hong Tao Li ◽  
Zhan Qiang Xu ◽  
Ben Rui Zhu
Keyword(s):  
Frequency Conversion ◽  
High Efficiency ◽  
Selection Process ◽  
Cooling Water ◽  
Economic Benefits ◽  
Gas Pipeline ◽  
Air Cooling ◽  
Water Cooling ◽  
Long Distance ◽  
First Choice

This document focuses on motors and frequency conversion equipments of stations of West-to-East Gas Pipeline, and introduces the present main cooling ways. Against water consumption, power consumption, and other economical index, analyze the selection process of cooling scheme in engineering design. Compare with the cost, workload of operation and maintenance of water cooling, air cooling and motor cooling. The result shows that water cooling is practicable in West-to-East Gas Pipeline and has validated in the established engineering. The method of scheme comparison proposed by this paper provides a reference for subsequent design.With the development of electronics technology, medium voltage high power frequency conversion speed regulation technology is increasingly mature. The technology that frequency conversion motor drives compressor unit has been gradually used in the long distance pipeline pressure field of oil and gas under the condition of reliable power supply, to replace the traditional gas turbine, and becomes the first choice of the pressurization equipment of the long distance pipeline, because of advantages of high technology, high efficiency, energy conservation and environment protection, economic benefits and so on[1-3].Stations of West-to-East Gas Pipeline are usually electrical driven. When the compressors operate, motors and frequency converters will produce large amounts of heat, which affects running state and equipment life. So choosing the economic and technological cooling water scheme is important for stations and the whole network to operate safely and stably[4-6].

Effect of Cooling Mode on Properties of a Cast Zinc Alloy

2013 ◽  
Vol 690-693 ◽  
pp. 66-69 ◽  
Author(s):  
Fei Zhang ◽  
Jin Gui Wan
Keyword(s):  
Material Properties ◽  
Cooling Water ◽  
Zinc Alloy ◽  
Air Cooling ◽  
Water Cooling ◽  
Cooling Mode ◽  
Comprehensive Properties ◽  
Alloy Material

In order to explore the best way of zinc alloy cooling, respectively adopting air cooling, water cooling, oil cooling and cooling in the furnace, to study its influence on the zinc alloy material properties. The results show that the oil cooling mode can improve the comprehensive properties of zinc alloy.

scholarly journals An Advanced Microturbine System with Water-Lubricated Bearings

2009 ◽  
Vol 2009 ◽  
pp. 1-12 ◽  
Author(s):  
Susumu Nakano ◽  
Tadaharu Kishibe ◽  
Tomoaki Inoue ◽  
Hiroyuki Shiraiwa
Keyword(s):  
Gas Turbines ◽  
High Performance ◽  
Unique Feature ◽  
Laboratory Evaluation ◽  
Air Cooling ◽  
Test Results ◽  
Air Turbine ◽  
Operation Test ◽  
Load Tests ◽  
Electrical Output

A prototype of the next-generation, high-performance microturbine system was developed for laboratory evaluation. Its unique feature is its utilization of water. Water is the lubricant for the bearings in this first reported application of water-lubricated bearings in gas turbines. Bearing losses and limitations under usage conditions were found from component tests done on the bearings and load tests done on the prototype microturbine. The rotor system using the water-lubricated bearings achieved stable rotating conditions at a rated rotational speed of 51,000 rpm. An electrical output of 135 kW with an efficiency of more than 33% was obtained. Water was also utilized to improve electrical output and efficiency through water atomizing inlet air cooling (WAC) and a humid air turbine (HAT). The operation test results for the WAC and HAT revealed the WAC and HAT operations had significant effects on both electrical output and electrical efficiency.

scholarly journals The Effect of the Cooling Process on the Crystalline Morphology and Dielectric Properties of Polythene

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2791
Author(s):  
Guang Yu ◽  
Boyang Yu
Keyword(s):  
Space Charge ◽  
Cooling Water ◽  
Dielectric Constants ◽  
Air Cooling ◽  
Water Cooling ◽  
Crystalline Morphology ◽  
Cooling Process ◽  
Experimental Frequency ◽  
Frequency Spectra ◽  
Two Samples

In this study, LDPE samples were prepared by melt blending with different cooling processes, which were natural air cooling, rapid air cooling, water cooling and oil cooling, respectively. According to polarization microscope (PLM) and differential scanning calorimeter (DSC) tests of these four low-density polyethylene (LDPE) samples, the effect of different cooling processes on polythene crystalline morphology could be studied. According to conductivity, dielectric frequency spectra and space charge tests, the effect of crystalline morphology on dielectric macroscopic properties could be explored. The microstructure characteristic results indicated the cooling medium significantly affected polythene crystalline morphology. When the samples were produced with natural air cooling, the crystalline grain size was large. On the other hand, after rapid air cooling, water cooling and oil cooling processes, the samples’ crystalline grain dispersed uniformly, and the grain sizes were lower. The space charge testing results indicate the samples produced with water cooling and oil cooling processes restrained the electrode injection in the process of pressurization. During short-circuits, the rates of charge release of these two samples were fast, and the remaining space charges were fewer. The conductivity and dielectric frequency spectra testing results indicated the conductivities of samples produced with water cooling and oil cooling processes were both less than those of samples produced with a natural air cooling process. Besides, with increasing experimental frequency, the relative dielectric constants of all testing samples decreased. Among them, the relative dielectric constant of the LDPE sample with the natural air cooling process was the largest. However, the crystalline structures of samples produced with rapid air cooling and water cooling processes were close, which restrained the movement of polymer macromolecule chains. Thus, the dielectric constants were lower. Additionally, because of the influence of relaxation polarization and dipole polarization, the dielectric losses of LDPE with water cooling and oil cooling processes increased to varying degrees.

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