Closed Loop Liquid Cooling for High Performance Computer Systems

2007 ◽  
Author(s):  
Sukhvinder Kang ◽  
David Miller ◽  
John Cennamo
Keyword(s):  
Computer System ◽  
High Performance ◽  
Closed Loop ◽  
Cooling System ◽  
High Heat ◽  
Low Noise ◽  
Heat Fluxes ◽  
Air Cooling ◽  
Heat Sources ◽  
Liquid Cooling

The power dissipation levels in high performance personal computers continue to increase rapidly while the silicon die temperature requirements remain unchanged or have been lowered. Advanced air cooling solutions for the major heat sources such as CPU and GPU modules use heat pipes and high flow rate fans to manage the heat load at the expense of significant increases in the sound power emitted by the computer system. Closed loop liquid cooling systems offer an excellent means to efficiently meet the combined challenges of high heat loads, low thermal resistance, and low noise while easily managing die level heat fluxes in excess of 500 W/cm2. This paper describes the design and attributes of an advanced liquid cooling system that can cool single or multiple heat sources within the computer system. The cooling system described use copper cold plates with meso scale channels to pick up heat from CPU and GPU type heat sources and highly efficient liquid-to-air heat exchangers with flat copper tubes and plain fins to transfer the heat to air by forced convection. A water based coolant is used for high thermal performance and additives are used to provide burst protection to the cooling system at temperatures down to −40 °C and corrosion protection to critical components. A highly reliable compact pump is used to circulate the fluid in a closed loop. The overall system is integrated using assembly methods and materials that enable very low fluid permeation for long life.

Heat Transfer Characteristics of a Train of Droplets Impinging Over a Hot Surface: From Film Evaporation to Leidenfrost Point

2019 ◽  
Author(s):  
Ganesh Guggilla ◽  
Arvind Pattamatta ◽  
Ramesh Narayanaswamy
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Heated Surface ◽  
Electronics Cooling ◽  
Spray Cooling ◽  
High Heat ◽  
Heat Fluxes ◽  
Air Cooling ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Abstract Due to the advancements in computing services such as machine learning and artificial intelligence, high-performance computing systems are needed. Consequently, the increase in electron chip density results in high heat fluxes and required sufficient thermal management to maintain the servers. In recent times, the liquid cooling techniques become prominent over air cooling as it has significant advantages. Spray cooling is one such efficient cooling process which can be implemented in electronics cooling. To enhance the knowledge of the process, detailed studies of fundamental mechanisms involved in spray cooling such as single droplet and multiple droplet interactions are required. The present work focuses on the study of a train of droplets impinging over a heated surface using FC-72 liquid. The surface temperature is chosen as a parameter, and the Dynamic Leidenfrost point (DLP) for the present impact conditions is identified. Spread hydrodynamics and heat transfer characteristics of these consecutively impinging droplets till the Leidenfrost temperature, are studied and compared.

MEMS Enabled Micro Spray Cooling System for Thermal Control of Electronic Chips

2001 ◽  
Author(s):  
S. C. Yao ◽  
C. H. Amon ◽  
K. Gabriel ◽  
P. Kumta ◽  
J. Y. Murthy ◽  
...  
Keyword(s):  
Cooling System ◽  
Surface Texturing ◽  
Thermal Control ◽  
Spray Cooling ◽  
Heat Fluxes ◽  
System Level ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Droplet Impingement ◽  
Dielectric Fluids

Abstract Liquid cooling of electronic devices becomes necessary when the chip-level heat fluxes increase and traditional air cooling encounters ever-increasing difficulties. From all the liquid cooling processes, spray cooling appears more successful due to its high critical heat flux, relatively low liquid flow rates, highly controllable, and the non-existence of boiling incipient hysterisis. This paper describes the development of the EDIFICE project (Embedded Droplet Impingement For Integrated Cooling of Electronics), which seeks to develop an integrated droplet impingement cooling device for removing chip heat fluxes in the range 50–100 W/cm2, employing latent heat of vaporization of dielectric fluids. Micro-spray nozzles are fabricated on silicon using MEMS technology to produce 100 micron droplets with odd shaped nozzles and swirling nozzles. The effects of shape, size, type of fluid, and swirling are tested and discussed. Spray heat transfer on silicon surfaces is studied with various surface texturing on the backside of the chip to promote spreading and evaporation of cold fluids as well as at heated conditions. The effects of configuration and fluids are revealed. Numerical modeling is used to study preliminary designs at both the device and system level. The paper describes progress made in the development of the EDIFICE device.

Electronics Thermal Management Using Advanced Hybrid Two-Phase Loop Technology

2007 ◽  
Author(s):  
Chanwoo Park ◽  
Aparna Vallury ◽  
Jon Zuo ◽  
Jeffrey Perez ◽  
Paul Rogers
Keyword(s):  
Thermal Management ◽  
High Performance ◽  
Cooling System ◽  
Active Flow Control ◽  
Heat Pipes ◽  
High Heat ◽  
Heat Fluxes ◽  
Significant Advance ◽  
Two Phase ◽  
Phase Loop

The paper discusses an advanced Hybrid Two-Phase Loop (HTPL) technology for electronics thermal management. The HTPL combined active mechanical pumping with passive capillary pumping realizing a reliable yet high performance cooling system. The evaporator developed for the HTPL used 3-dimensional metallic wick structures to enhance boiling heat transfer by passive capillary separation of liquid and vapor phases. Through the testing using various prototype hybrid loops, it was demonstrated that the hybrid loops were capable of removing high heat fluxes from multiple heat sources with large surface areas up to 135cm2 and 10kW heat load. Because of the passive capillary phase separation, the hybrid loop operation didn’t require any active flow control of the liquid in the evaporator, even at highly transient and asymmetrical heat inputs between the evaporators. These results represent the significant advance over state-of-the-art heat pipes, loop heat pipes and evaporative spray cooling devices in terms of performance, robustness and simplicity.

Reliability Challenges in Design and Operation of High Heat Powered Processors

2005 ◽  
Author(s):  
Ali Heydari ◽  
Vadim Gektin
Keyword(s):  
Heat Flux ◽  
Closed Loop ◽  
Heat Removal ◽  
High Heat ◽  
Electrical Signal ◽  
Open Loop ◽  
Heat Fluxes ◽  
High Heat Flux ◽  
Air Cooling ◽  
Interconnect Design

Advances in processor design have been made possible in part by increases in the packaging density of electronics. At the same time, combination of increased power dissipation and packaging density has led to substantial growth in the chip and system heat fluxes and amplified complexity in electrical signal integrity and mechanical stack-up design in the recent years, particularly, in the high-end computers. With the trend towards miniaturization, heat removal, along with increased reliability requirements, has become a major bottleneck in product development, especially, in low profile systems, telecom servers and blades. Cooling of high heat flux components may require consideration of innovative open-loop, as well as plausible closed-loop, cooling designs for data centers. This paper addresses reliability aspects of thermal, electrical, mechanical, and interconnect design and long-life operation of high-end air-cooling, as well as feasible active open and closed-loop cooling technologies of high heat flux processors.

Experimental and Analytical Investigation of Compact Liquid Cooled Heat Sinks

2004 ◽  
Author(s):  
M. Zugic ◽  
J. R. Culham ◽  
P. Teertstra ◽  
Y. Muzychka ◽  
K. Horne ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Tests ◽  
Reynolds Numbers ◽  
High Heat ◽  
Analytical Investigation ◽  
Boundary Resistance ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Air Cooling ◽  
Design Tools

Compact, liquid cooled heat sinks are used in applications where high heat fluxes and boundary resistance preclude the use of more traditional air cooling techniques. Four different liquid cooled heat sink designs, whose core geometry is formed by overlapped ribbed plates, are examined. The objective of this analysis is to develop models that can be used as design tools for the prediction of overall heat transfer and pressure drop of heat sinks. Models are validated for Reynolds numbers between 300 and 5000 using experimental tests. The agreement between the experiments and the models ranges from 2.35% to 15.3% RMS.

Plasma Sprayed Ultra High Temperature Ceramics for Thermal Protection Systems

2000 ◽  
Author(s):  
T. Valente ◽  
C. Bartuli ◽  
G. Visconti ◽  
M. Tului
Keyword(s):  
Plasma Spraying ◽  
High Performance ◽  
Thermal Protection ◽  
Electrical Discharge Machining ◽  
High Heat ◽  
Heat Fluxes ◽  
Space Vehicles ◽  
Ultra High Temperature Ceramics ◽  
Protection Systems ◽  
Plasma Sprayed

Abstract Reusable space vehicles, which must withstand re-entry into the Earth's atmosphere, require external protection systems (TPS) which are usually in the forms of rigid surface in areas of high or moderate working temperature. High heat fluxes and temperatures related to high performance hypervelocity flights also require the use of TPS materials having good oxidation and thermal shock resistance, dimensional stability, and ablation resistance. Components by these materials are usually fabricated, starting from either billets or plate stocks, by uniaxial hot pressing, and complex parts, such as low radius edges, are then obtained by electrical discharge machining technique. This article investigates an alternative fabrication technology, based on plasma spraying, to produce near net shape components. Results of experimental activities, such as optimization of plasma spraying parameters based on a DOE approach, are reported and discussed.

scholarly journals Influence of the ambient temperature on the cooling efficiency of the high performance cooling device with thermosiphon effect

2018 ◽  
Vol 180 ◽  
pp. 02073
Author(s):  
Patrik Nemec ◽  
Milan Malcho
Keyword(s):  
Ambient Temperature ◽  
High Performance ◽  
Convection Heat Transfer ◽  
Heat Removal ◽  
Measuring Method ◽  
High Heat ◽  
Heat Fluxes ◽  
High Heat Flux ◽  
Cooling Efficiency ◽  
Cooling Device

This work deal with experimental measurement and calculation cooling efficiency of the cooling device working with a heat pipe technology. The referred device in the article is cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description, working principle and construction of cooling device. The main factor affected the dissipation of high heat flux from electronic elements through the cooling device to the surrounding is condenser construction, its capacity and option of heat removal. Experimental part describe the measuring method cooling efficiency of the cooling device depending on ambient temperature in range -20 to 40°C and at heat load of electronic components 750 W. Measured results are compared with results calculation based on physical phenomena of boiling, condensation and natural convection heat transfer.

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.

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