scholarly journals Investigation of Heat Management in High Thermal Density Communication Cabinet by a Rear Door Liquid Cooling System

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4385
Author(s):  
Wansheng Yang ◽  
Lin Yang ◽  
Junjie Ou ◽  
Zhongqi Lin ◽  
Xudong Zhao
Keyword(s):  
Data Center ◽  
Heat Dissipation ◽  
Cooling System ◽  
Operating Temperature ◽  
High Heat ◽  
Transformer Oil ◽  
Cooling Efficiency ◽  
Domestic Water ◽  
Maximum Heat ◽  
Rear Door

In this paper, a rear door oil-cooling heat exchanger for data center cabinet-level cooling has been proposed. In order to solve the heat dissipation problem of high heat density data center, this paper applied the mature transformer oil cooling technology to the data room. The heat dissipation of liquid-cooled cabinets and traditional air-cooled cabinets was compared, and the heat dissipation performance of the oil-cooled system was theoretically and experimentally investigated. To investigate the heat dissipation system, the cabinet operating temperature, circulating oil system temperature and cabinet exhaust temperature, cabinet heat density, oil flow rates and fan power were analyzed. It was found that the average cooling efficiency of the liquid-cooled cabinet increased by 66% compared with the average cooling efficiency of the conventional air-cooled cabinet. The operating temperature in air-cooled cabinets is as high as 55 °C, and the operating temperature in liquid-cooled cabinets does not exceed 50 °C. Among which, the maximum heat dissipation efficiency of the liquid-cooled cabinets can reach 58.8%. The oil temperature could reach 46.9 °C after heat exchange, and the exhaust air of the cabinet could reach 42.8 °C, which could be used to prepare domestic water and regenerative desiccant. The results from established calculation model agreed well with the testing results and the model could be used to predict the heat dissipation law of the oil cooling system under different conditions. The research has proposed the potential application of the oil-cooled in cabinet-level cooling, which can help realize saving primary energy and reducing carbon emission.

From Chip to Cooling Tower Data Center Modeling: Chip Leakage Power and its Impact on Cooling Infrastructure Energy Efficiency

2011 ◽  
Author(s):  
Thomas J. Breen ◽  
Ed J. Walsh ◽  
Jeff Punch ◽  
Amip J. Shah ◽  
Cullen E. Bash ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Data Center ◽  
Heat Dissipation ◽  
Linear Models ◽  
Operating Temperature ◽  
Leakage Power ◽  
Operating Conditions ◽  
Operating Temperatures ◽  
The Impact

The power consumption of the chip package is known to vary with operating temperature, independently of the workload processing power. This variation is commonly known as chip leakage power, typically accounting for ∼10% of total chip power consumption. The influence of operating temperature on leakage power consumption is a major concern for the IT industry for design optimization where IT system power densities are steadily increasing and leakage power expected to account for up to ∼50% of chip power in the near future associated with the reducing package size. Much attention has been placed on developing models of the chip leakage power as a function of package temperature, ranging from simple linear models to complex super-linear models. This knowledge is crucial for IT system designers to improve chip level energy efficiency and minimize heat dissipation. However, this work has been focused on the component level with little thought given to the impact of chip leakage power on entire data center efficiency. Studies on data center power consumption quote IT system heat dissipation as a constant value without accounting for the variance of chip power with operating temperature due to leakage power. Previous modeling techniques have also omitted this temperature dependent relationship. In this paper we discuss the need for chip leakage power to be included in the analysis of holistic data center performance. A chip leakage power model is defined and its implementation into an existing multi-scale data center energy model is discussed. Parametric studies are conducted over a range of system and environment operating conditions to evaluate the impact of varying degrees of chip leakage power. Possible strategies for mitigating the impact of leakage power are also illustrated in this study. This work illustrates that when including chip leakage power in the data center model, a compromise exists between increasing operating temperatures to improve cooling infrastructure efficiency and the increase in heat load at higher operating temperatures due to leakage power.

Experimental Investigation on Flow and Thermal Characteristics of a Micro Phase-Change Cooling System With a Microgroove Evaporator

2006 ◽  
Author(s):  
Xuegong Hu ◽  
Dawei Tang
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Dissipation ◽  
Cooling System ◽  
Thermal Sensitivity ◽  
Thermal Characteristics ◽  
Cooling Capacity ◽  
Input Power ◽  
Maximum Heat ◽  
Transportation Capacity

In this paper, a natural convection micro cooling system with a capillary microgroove evaporator is proposed. An experimental study on the characteristics of thermal resistance, pressure drop and heat transfer of the cooling system was carried out. Experimental results indicate that the liquid fill ratio has a significant influence on thermal resistance and heat transfer in the cooling system. Increasing system’s cooling capacity at higher input power depends on decreasing the thermal resistance between the outer surfaces of the condenser and ambient environment. Compared with a flat miniature heat pipe (FMHP) and a current fan-cooled radiator for CPU chip of Pentium IV, the present micro cooling system has a stronger heat dissipation capacity. Its best cooling performance at a surface temperature of heat source below 373K reaches 1.68×106W/m2 and the maximum heat transportation capacity is 131.8W. The novel kind of cooling system is suitable for remote cooling of those electronic parts with micro size, high power and thermal sensitivity.

scholarly journals Heat Dissipation Characteristics of a FSAE Racecar Radiator

2021 ◽  
Vol 39 (5) ◽  
pp. 1667-1672
Author(s):  
Shreyas Padmaraman ◽  
Nagarathnam Rajesh Mathivanan ◽  
Babu Rao Ponangi
Keyword(s):  
Surface Area ◽  
Internal Combustion Engines ◽  
Heat Dissipation ◽  
Cooling System ◽  
Operating Temperature ◽  
Experimental Investigations ◽  
Inlet Temperature ◽  
Combustion Engines ◽  
Significant Drop ◽  
Race Car

In recent times, the rise in performance and power of internal combustion engines has resulted in an increased demand for more efficient cooling systems. Customized engineered coolants, additives, radiator materials, redesigned coolant pumps and radiators help to meet these increased demands. In case of FSAE racecar, designing a radiator is an important part for controlling the engine operating temperature and increasing the effectiveness of the cooling system. In this work, an attempt is made to develop a simple yet reasonably accurate analytical model to calculate the effectiveness of a radiator. The model is then applied to predict the operating temperature of the engine at varying load conditions. Experimental investigations were performed using a customized radiator test rig to replicate the field test conditions. The rate of heat dissipation through the radiator with respect to the inlet temperature is analyzed by changing the surface area of the radiator. The developed model is able to predict the engine operating temperature in close agreement with the experimentation conducted. A marginal increase in surface area of the radiator resulted in significant drop in engine operating temperature. Thereby reduction in engine operating temperature will boost the performance of FSAE race car.

Enhanced Pool Boiling With HFE7000 Over Selectively Sintered Microchannels

2017 ◽  
Author(s):  
Travis S. Emery ◽  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Pool Boiling ◽  
Electronics Cooling ◽  
Fold Increase ◽  
High Heat ◽  
Heat Fluxes ◽  
Dielectric Fluid ◽  
Maximum Heat ◽  
Maximum Heat Transfer

As the need for efficient thermal management grows, pool boiling’s ability to dissipate high heat fluxes has gained significant interest. The objective of this work was to study the performance of pool boiling at atmospheric pressure using a dielectric fluid, HFE7000. Both plain and enhanced copper surfaces were tested, and these results were then compared to similar testing performed with water and FC-87. The enhanced surfaces utilized microchannels with porous coatings selectively located on different regions of the heat transfer surface. A maximum critical heat flux (CHF) of 41.7 W/cm2 was achieved here, which translated to a 29% CHF increase in comparison to a plain chip. A maximum heat transfer coefficient (HTC) of 104.0 kW/m2°C was also achieved, which translated to a 6-fold increase in HTC when compared to a plain copper chip. More notably, this HTC was achieved at a wall temperature of 38.4 °C. This HTC enhancement was greater than that of water and FC-87 when using the same enhanced surface. The effect of sintering location was found to have a similar effect on CHF with HFE7000 in comparison with water. The effect of microchannel size was shown to have similar effects on CHF when compared with FC-87 and water. From the results found here, it is concluded that the employment of selectively sintered open microchannels with HFE7000 has significant potential for enhanced heat dissipation in electronics cooling applications.

scholarly journals POWER, METALLURGICAL AND CHEMICAL MECHANICAL ENGINEERING CRYOGENIC INSTRUMENT REFRIGERATING BY LIQUID NITROGEN IN UNDERHEATED CONDUCTION

2019 ◽  
Vol 46 (1) ◽  
pp. 19-31
Author(s):  
A. V. Glushaev ◽  
V. N. Zamarashkina ◽  
T. A. Malysheva ◽  
E. V. Sokolova
Keyword(s):  
Liquid Nitrogen ◽  
Heat Dissipation ◽  
Cooling System ◽  
Optimal Solution ◽  
Quality Criteria ◽  
High Heat ◽  
Surgical Instruments ◽  
Hydraulic Loss ◽  
High Heat Flux ◽  
Long Time

Objectives. Cryogenic surgical instruments have been successfully used to conduct tumor ablation. For a long time, cryoablation procedures in Russia were carried out using cryodestructors cooled with liquid nitrogen, which are able to remove heat from the ablation object with high heat flux density and quickly form a cryoablation zone, while being relatively cheap and easy to operate. However, these instruments turned out to be unsuitable for minimally invasive surgeries; therefore, they are squeezed out of practical medicine and cryosurgical instruments are cooled by throttling argon gas. This led to the purpose of the study - the choice of equipment for the organization of local supercooling of pathological tissue.Method. To solve the problem of optimizing the cryogenic pipeline, a method was chosen for finding the Pareto-optimal solution. To solve this problem, it is sufficient to increase the pressure in the fluid flow directed to the NCS using a liquid micropump. In the role of quality criteria in this task, we selected: hydraulic loss power and heat loss power.Result. The following results were obtained: the minimum pressure in the vessel, which ensures the movement of the fluid in a single-phase state, according to the magi-line of 1 m length is 0.75 MPa; With this pressure, through a line with a diameter of 1 mm, the flow rate is maintained up to 6 kg / h; heat dissipation ability of the instrument reaches 608 watts. The thermal load on the cooling system of the heatdissipating device of the device for CA is unsteady and is formed due to the heat reserve accumulated in the patient's tissues.Conclusion. The use of liquid nitrogen in the undersized cryosurgical equipment makes it possible to overcome the noted drawbacks of liquid cryodestructors.

scholarly journals A novel therapeutic strategy of multimodal nanoconjugates for state-of-the-art brain tumor phototherapy

2022 ◽  
Vol 20 (1) ◽  
Author(s):  
Hyung Shik Kim ◽  
Minwook Seo ◽  
Tae-Eun Park ◽  
Dong Yun Lee
Keyword(s):  
Oral Administration ◽  
Heat Dissipation ◽  
High Efficiency ◽  
Oral Absorption ◽  
High Heat ◽  
Ros Generation ◽  
Photoconversion Efficiency ◽  
Mice Model ◽  
Maximum Heat ◽  
Aunp Surface

Abstract Background The outcome of phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) for glioblastoma multiforme (GBM), is disappointing due to insufficient photoconversion efficiency and low targeting rate. The development of phototherapeutic agents that target GBM and generate high heat and potent ROS is important to overcome the weak anti-tumor effect. Results In this study, nanoconjugates composed of gold nanoparticles (AuNPs) and photosensitizers (PSs) were prepared by disulfide conjugation between Chlorin e6 (Ce6) and glutathione coated-AuNP. The maximum heat dissipation of the nanoconjugate was 64.5 ± 4.5 °C. Moreover, the proximate conjugation of Ce6 on the AuNP surface resulted in plasmonic crossover between Ce6 and AuNP. This improves the intrinsic ROS generating capability of Ce6 by 1.6-fold compared to that of unmodified-Ce6. This process is called generation of metal-enhanced reactive oxygen species (MERos). PEGylated-lactoferrin (Lf-PEG) was incorporated onto the AuNP surface for both oral absorption and GBM targeting of the nanoconjugate (denoted as Ce6-AuNP-Lf). In this study, we explored the mechanism by which Ce6-AuNP-Lf interacts with LfR at the intestinal and blood brain barrier (BBB) and penetrates these barriers with high efficiency. In the orthotopic GBM mice model, the oral bioavailability and GBM targeting amount of Ce6-AuNP-Lf significantly improved to 7.3 ± 1.2% and 11.8 ± 2.1 μg/kg, respectively. The order of laser irradiation, such as applying PDT first and then PTT, was significant for the treatment outcome due to the plasmonic advantages provided by AuNPs to enhance ROS generation capability. As a result, GBM-phototherapy after oral administration of Ce6-AuNP-Lf exhibited an outstanding anti-tumor effect due to GBM targeting and enhanced photoconversion efficiency. Conclusions The designed nanoconjugates greatly improved ROS generation by plasmonic crossover between AuNPs and Ce6, enabling sufficient PDT for GBM as well as PTT. In addition, efficient GBM targeting through oral administration was possible by conjugating Lf to the nanoconjugate. These results suggest that Ce6-AuNP-Lf is a potent GBM phototherapeutic nanoconjugate that can be orally administered. Graphical Abstract

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.

From Chip to Cooling Tower Data Center Modeling: Chip Leakage Power and Its Impact on Cooling Infrastructure Energy Efficiency

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Thomas J. Breen ◽  
Ed J. Walsh ◽  
Jeff Punch ◽  
Amip J. Shah ◽  
Cullen E. Bash ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Data Center ◽  
Heat Dissipation ◽  
Linear Models ◽  
Operating Temperature ◽  
Leakage Power ◽  
Operating Conditions ◽  
Operating Temperatures ◽  
The Impact

The power consumption of the chip package is known to vary with operating temperature, independently of the workload processing power. This variation is commonly known as chip leakage power, typically accounting for ~10% of total chip power consumption. The influence of operating temperature on leakage power consumption is a major concern for the information technology (IT) industry for design optimization where IT system power densities are steadily increasing and leakage power expected to account for up to ~50% of chip power in the near future associated with the reducing package size. Much attention has been placed on developing models of the chip leakage power as a function of package temperature, ranging from simple linear models to complex super-linear models. This knowledge is crucial for IT system designers to improve chip level energy efficiency and minimize heat dissipation. However, this work has been focused on the component level with little thought given to the impact of chip leakage power on entire data center efficiency. Studies on data center power consumption quote IT system heat dissipation as a constant value without accounting for the variance of chip power with operating temperature due to leakage power. Previous modeling techniques have also omitted this temperature dependent relationship. In this paper, we discuss the need for chip leakage power to be included in the analysis of holistic data center performance. A chip leakage power model is defined and its implementation into an existing multiscale data center energy model is discussed. Parametric studies are conducted over a range of system and environment operating conditions to evaluate the impact of varying degrees of chip leakage power. Possible strategies for mitigating the impact of leakage power are also illustrated in this study. This work illustrates that when including chip leakage power in the data center model, a compromise exists between increasing operating temperatures to improve cooling infrastructure efficiency and the increase in heat load at higher operating temperatures due to leakage power.

A Study of Air Flow through Perforated Tile for Air Conditioning System in Data Center

2012 ◽  
Vol 249-250 ◽  
pp. 126-131 ◽  
Author(s):  
Jetsadaporn Priyadumkol ◽  
Chawalit Kittichaikarn
Keyword(s):  
Data Center ◽  
Air Conditioning ◽  
Heat Dissipation ◽  
Cooling System ◽  
Air Flow ◽  
Heat Index ◽  
Energy Usage ◽  
Air Conditioning System ◽  
Airflow Distribution ◽  
Air Flow Velocity

The power trend of using server systems in data center is continuously increasing. Cooling system consumed 38% of total energy usage which is a significant contribution in the energy consumption. As a result, the efficient energy usage in data center is concerned.Normally a raised-floor is widely used in data center cooling system which delivers cool air through perforated tiles to a front of server racks. However it is usually found that this cool air cannot effectively remove a heat dissipation at the top of server racks. Therefore, the environmental condition in data center must be designed strictly to avoid disruption that caused by overheat.This paper gives some guidelines to help in the better design. Commercial Computational Fluid Dynamics (CFD) program was used to analyze the air flow from raised-floor air conditioning system. A tetrahedral of 1.8 million meshes with k- turbulence model were used to obtain the air flow velocity and temperature distributions in the room. The model was validated by comparing simulation results with actual measurements. As a result, dimensionless parameters in the form of supply heat index(SHI), for understanding the optimization of relative airflow distribution to the heat load of server rack was found. It shows that these parameters provide an effective tool to the improvement of energy efficiency in raised floor data center.

Dynamic Analysis of Hybrid Cooling Data Centers Subjects to the Failure of CRAC Units

2013 ◽  
Author(s):  
Tianyi Gao ◽  
Emad Samadiani ◽  
Roger Schmidt ◽  
Bahgat Sammakia
Keyword(s):  
Data Center ◽  
Heat Exchangers ◽  
Data Centers ◽  
Cooling System ◽  
Normal Operation ◽  
Air Cooling ◽  
Rear Door ◽  
Hybrid Cooling ◽  
Air Cooling System ◽  
The Impact

Thermal management of high power data centers poses challenges due to the high operational cost which is made worse due to the many inefficiencies that arise in them. Additional challenges arise due to the dynamic behaviors that occur during normal operation, and also during emergencies such as power outages or failure of some or all of the cooling equipment. Water and hybrid air plus water cooled data centers are an alternate cooling solution combining liquid cooling systems, such as rear door heat exchangers located within the racks themselves, in addition to the traditional raised floor cold aisle air cooling system. Such a solution may be used when some of the equipment in a data center is upgraded to higher end and higher power equipment which may not be manageable with the existing air cooling system. For a data center with a hybrid cooling system, the cold air supply and the cold water supply should increase in case of an emergency, such as a CRAC (Computer Room Air Conditioner) units’ failure. In this paper, a detailed computational study is conducted to investigate the dynamic response of the impact of a CRAC failure on both water side and air side in a representative hybrid cooling room. The room studied is an air cooled data center using the common cold aisle approach, with rear door heat exchangers installed on all of the racks. CRAC failure is investigated in a hybrid cooling room. The variation and fluctuation in an average rack inlet temperature, and inlet temperatures at different detail locations are presented in plots, showing the dynamic performance of a hybrid cooling data center subjected to the different CRAC failure scenarios. Different response time studies are also presented in this paper.

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