Reliability Considerations for Oil Immersion-Cooled Data Centers

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Jimil M. Shah ◽  
Richard Eiland ◽  
Pavan Rajmane ◽  
Ashwin Siddarth ◽  
Dereje Agonafer ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Cooling System ◽  
Chemical Properties ◽  
Cost Savings ◽  
Dielectric Strength ◽  
Mineral Oil ◽  
Circuit Board ◽  
Air Cooling ◽  
Immersion Cooling ◽  
Oil Immersion

The improved efficiency of mineral oil may offer simplicity in facility design compared to traditional air cooling and provide a means for cost savings. Despite its improved cooling efficiency and cost savings, a mineral oil immersion cooling technique is still not widely implemented and original equipment manufacturers are reluctant to jeopardize sales of existing air-based cooling system equipment. Only compelling physics regarding thermal performance of direct immersion cooling is not enough for data center operators. Many uncertainties and concerns persist regarding the effects of mineral oil immersion cooling on the reliability of information technology (IT) equipment both at the component and chassis level. This paper is a first attempt at addressing this challenge by reviewing the changes in physical and chemical properties of IT equipment materials like polyvinyl chloride (PVC), printed circuit board (PCB), and capacitors and characterizes the interconnect reliability of materials. The changes in properties of a mineral oil like kinematic viscosity and dielectric strength are also cited as important factors and discussed briefly. The changes in mechanical properties like elasticity, hardness, swelling, and creep are being shown in the paper for thermoplastic materials. The chemical reaction between material and mineral oil as a function of time and temperature is also conferred. The literature gathered on the subject and quantifiable data gathered by the authors provide the primary basis for this research document.

Evaluating the Reliability of Passive Server Components for Single-Phase Immersion Cooling

2021 ◽  
Author(s):  
Jimil M. Shah ◽  
Keerthivasan Padmanaban ◽  
Hrishabh Singh ◽  
Surya Duraisamy Asokan ◽  
Satyam Saini ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Single Phase ◽  
Printed Circuit Board ◽  
Structural Integrity ◽  
Circuit Board ◽  
Dielectric Fluid ◽  
Air Cooling ◽  
Passive Components ◽  
Material Compatibility ◽  
Immersion Cooling

Abstract The adoption of Single-phase Liquid Immersion Cooling (Sp-LIC) for Information Technology equipment provides an excellent cooling platform coupled with significant energy savings. There are, however, very limited studies related to the reliability of such cooling technology. The Accelerated Thermal Cycling (ATC) test given ATC JEDEC is relevant just for air cooling but there is no such standard for immersion cooling. The ASTM benchmark D3455 with some appropriate adjustments was adopted to test the material compatibility because of the air and dielectric fluid differences in the heat capacitance property and corresponding ramp rate during thermal cycling. For this study, accelerated thermal degradation of the printed circuit board (PCB), passive components, and fiber optic cables submerged in air, white mineral oil, and synthetic fluid at a hoisted temperature of 45C and 35% humidity is undertaken. This paper serves multiple purposes including designing experiments, testing and evaluating material compatibility of PCB, passive components, and optical fibers in different hydrocarbon oils for single-phase immersion cooling. Samples of different materials were immersed in different hydrocarbon oils and air and kept in an environmental chamber at 45C for a total of 288 hours. Samples were then evaluated for their mechanical and electrical properties using Dynamic Mechanical Analyzer (DMA) and a multimeter, respectively. The cross-sections of some samples were also investigated for their structural integrity using SEM. The literature gathered on the subject and quantifiable data gathered by the authors provide the primary basis for this research document.

Design Considerations Relating to Non-Thermal Aspects of Oil Immersion Cooling

2016 ◽  
Author(s):  
Jimil M. Shah ◽  
Syed Haider I. Rizvi ◽  
Indu Sravani Kota ◽  
Sahithi Reddy Nagilla ◽  
Dhaval Thakkar ◽  
...  
Keyword(s):  
Data Center ◽  
Data Centers ◽  
Energy Savings ◽  
Cost Savings ◽  
Mineral Oil ◽  
Critical Element ◽  
Air Cooling ◽  
Cooling Fluid ◽  
Trade Offs ◽  
Oil Immersion

Full submersion of servers in dielectric oils offers an opportunity for significant cooling energy savings and increased power densities for data centers. The enhanced thermal properties of oil can lead to considerable savings in both the upfront and operating costs over traditional air cooling methods. Despite recent findings showing the improved cooling efficiency and cost savings of oil as a cooling fluid, this technique is still not widely adopted. Many uncertainties and concerns persist regarding the non-thermal aspects of an oil immersion cooled data center. This paper presents useful information regarding a variety of factors related to the operation of an oil cooled data center. Pertinent material property considerations such as the chemistry, flammability, material compatibility, human health effects, and sustainability of mineral oil are discussed. A general introduction as to the chemical composition and production of mineral oil is provided. A discussion of the trade-offs in thermal performance and cost of the mineral oil is presented. The dielectric nature of oils is critical to their success as a cooling fluid for electronic applications. Factors such as temperature, voltage, and age that affect this property are reviewed. Flammability of oils is a valid concern when immersing costly IT equipment and the pertinent concerns of this aspect are reviewed. The evaporation loss of oil is also mentioned as refueling and safety are important parameters in the establishment of any facility. Leeching of materials, especially plastics, is a reoccurring concern expressed regarding mineral oil immersed IT equipment. Mineral oils are by-products of petroleum refining processes and as such may bring forth sustainability concerns associated with their use and disposal. The long term stability and performance of key physical and material parameters of oils used in applications such as high voltage power are typically monitored. The similarity and implications of the longevity of oils, when used for data center applications, will be examined. Other issues related to the design, operation, and serviceability of submerged IT equipment and racks will also be addressed. Switching to an oil immersion cooled data center typically brings about several designs and operational changes compared to a typical air-cooled approach. A critical element of oil cooling often cited by opponents of the technology is the issue of serviceability of IT equipment. This paper will discuss some of the additional features a data center may need in place to help alleviate these concerns, as well as, best practices based on experience and observations by the authors. This paper also includes Cup Burner Experiment as per ISO 14520/NFPA 2001 standard to determine the minimum design concentration of fire extinguishing agent for the class B hazard of heavy mineral oil and the class C hazard of electronic equipment as a part of the safety concerns for oil cooled data centers. The visual observations of the servers after immersion in oil for 8 months are also explained for a better view of the system related issues. The discussion presented here is based primarily on literature gathered on the subject and quantifiable data gathered by the authors.

scholarly journals Thermal Performance and Efficiency of a Mineral Oil Immersed Server Over Varied Environmental Operating Conditions

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Richard Eiland ◽  
John Edward Fernandes ◽  
Marianna Vallejo ◽  
Ashwin Siddarth ◽  
Dereje Agonafer ◽  
...  
Keyword(s):  
Flow Rate ◽  
Thermal Performance ◽  
Data Center ◽  
Mineral Oil ◽  
Operating Conditions ◽  
Published Data ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Bulk Fluid ◽  
Oil Immersion

Complete immersion of servers in dielectric mineral oil has recently become a promising technique for minimizing cooling energy consumption in data centers. However, a lack of sufficient published data and long-term documentation of oil immersion cooling performance make most data center operators hesitant to apply these approaches to their mission critical facilities. In this study, a single server was fully submerged horizontally in mineral oil. Experiments were conducted to observe the effects of varying the volumetric flow rate and oil inlet temperature on thermal performance and power consumption of the server. Specifically, temperature measurements of the central processing units (CPUs), motherboard (MB) components, and bulk fluid were recorded at steady-state conditions. These results provide an initial bounding envelope of environmental conditions suitable for an oil immersion data center. Comparing with results from baseline tests performed with traditional air cooling, the technology shows a 34.4% reduction in the thermal resistance of the system. Overall, the cooling loop was able to achieve partial power usage effectiveness (pPUECooling) values as low as 1.03. This server level study provides a preview of possible facility energy savings by utilizing high temperature, low flow rate oil for cooling. A discussion on additional opportunities for optimization of information technology (IT) hardware and implementation of oil cooling is also included.

Numerical Analysis of Oil Immersion Cooling of a Server Using Mineral Oil and Al2o3 Nanofluid

2021 ◽  
Author(s):  
Amirreza Niazmand ◽  
Prajwal Murthy ◽  
Satyam Saini ◽  
Pardeep Shahi ◽  
Pratik Bansode ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Mineral Oil ◽  
Immersion Cooling ◽  
Oil Immersion ◽  
Al2o3 Nanofluid

A Numerical Study of Single Phase Dielectric Fluid Immersion Cooling of Multichip Modules

2012 ◽  
Vol 2012 (1) ◽  
pp. 000581-000590
Author(s):  
Roy W. Knight ◽  
Seth Fincher ◽  
Sushil H. Bhavnani ◽  
Daniel K. Harris ◽  
R. Wayne Johnson
Keyword(s):  
Single Phase ◽  
Printed Circuit Board ◽  
Numerical Study ◽  
Design Guidelines ◽  
Circuit Board ◽  
Dielectric Fluid ◽  
Multichip Modules ◽  
Ansys Fluent ◽  
Immersion Cooling ◽  
Numerical Parametric Study

Immersion, single phase free convection cooling of multichip modules on a printed circuit board in a pool of dielectric fluid was examined numerically, with experimental verification of baseline cases. A multi-chip module with multiple thermal test cells with temperature sensing capability was simulated. The commercially available computational fluid dynamics program from ANSYS, Fluent, was used with the electronics packaging front end, Icepak, employed to create the models and compact conduction modules. Simulations were first performed of an experimental test vehicle which had five 18 mm by 18 mm die, arranged in a cross pattern, equally spaced die, 25 mm between them. Two of the die were aligned vertically with the center die, two aligned horizontally with it. The board was suspended vertically in a large pool of dielectric fluid. Heat was dissipated in the die at a flux of up to 2 W/cm2, based on the die surface area. Simulation results were compared with experimentally measured die temperature values and excellent agreement was seen for the cases of one die heated and all five die uniformly heated with the board cooled by FC-72. A numerical parametric study was performed to examine the effect of die size and spacing on temperature rise. In addition to FC-72, immersion cooling in Novec 649 and HFE 7100 were modeled. Design guidelines are suggested for dielectric fluid immersion cooled multichip modules.

RF Capacitor Material for Use in Printed Circuit Board

2013 ◽  
Vol 2013 (1) ◽  
pp. 000507-000510
Author(s):  
Jin-Hyun Hwang ◽  
John Andresakis ◽  
Ethan Feinberg ◽  
Bob Carter ◽  
Yuji Kageyama ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Temperature Stability ◽  
Dielectric Strength ◽  
Polymer Composite Material ◽  
Circuit Board ◽  
Discrete Elements ◽  
Low Loss ◽  
Printed Circuit ◽  
Material Issue ◽  
High Dielectric

A novel ceramic-functional-particle-filled polymer composite material has been developed for the use either in discrete elements on the printed circuit board or in being embedded within the packaging substrate for high frequency circuit applications. This material provides the desired properties such as low loss at high frequencies, about 0.002 or less up to 10GHz, and high dielectric strength, among other improved properties. The electrical properties were influenced significantly by the ceramic-functional-particle, i.e. type and particle size/distribution in the polymer matrix. Their contributions to the electric strength and temperature stability of capacitance which is an important material issue for practical device application will be discussed. In addition, capacitance tolerance for manufacturing embedded RF capacitor will be presented in terms of etching uniformity to minimize the variation of the capacitor electrode areas.

A Study on the Characteristics of a Vibrator Using Flat PCB-Coil

2013 ◽  
Vol 392 ◽  
pp. 738-742 ◽  
Author(s):  
Hyung Sik Kim ◽  
Sang Pyo Hong ◽  
Mi Hyun Choi ◽  
Hyun Joo Kim ◽  
In Hwa Lee ◽  
...  
Keyword(s):  
Vibration Amplitude ◽  
Printed Circuit Board ◽  
Cooling System ◽  
Sine Wave ◽  
Circuit Board ◽  
Frequency Change ◽  
Tactile Stimulator ◽  
Custom Made ◽  
Wide Range ◽  
Fiberglass Cloth

In this study, we developed and evaluateda vibrator using a flat PCB-coil. The flat PCB-coil vibrator was fabricated on a printed circuit board using and etching process. The spiral pattern was etched on a fiberglass cloth with an epoxy resin. To evaluatethe flat PCB-coil vibrator, we generated a sine wave, saw-tooth, and square wave through a custom made wave generator and amplified the waveforms using a power amplifier. A three-axis accelerometer was used to evaluate the performance of the developed vibrator. Even though the developed vibrator is simple, it has a wide range of vibration frequency (50~500 Hz) and vibration amplitude (0~5 V). The vibration amplitude does not change due to frequency change. It is expected that the developed vibrator can be used in a wide variety of applications such as in a tactile stimulator, in elastography, energy harvesting, and in a cooling system.

scholarly journals THERMOELECTRIC SYSTEM FOR PROVIDING A HEAT REGIME FOR MODULAR ELECTRONIC EQUIPMENT

2020 ◽  
Vol 46 (4) ◽  
pp. 53-64 ◽  
Author(s):  
Sh. A. Yusufov ◽  
A. M. Ibragimova ◽  
S. A. Peredkov ◽  
T. E. Sarkarov ◽  
R. G. Mitarov
Keyword(s):  
Printed Circuit Board ◽  
Cooling System ◽  
Air Flow ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Electronic Equipment ◽  
Circuit Board ◽  
Thermoelectric Cooling ◽  
Printed Circuit ◽  
Testing Stand

Objectives. The article discusses a thermoelectric cooling system (TECS) for ensuring the thermal regime of modular electronic equipment (MEE) located in a cabinet. The main task of the experimental studies is to determine the temperature dependencies of the air-cooled heat-generating elements of a printed circuit board simulator according to TEСS parameters.Method. In order to conduct experimental studies of a thermoelectric cooling system for printed circuit boards in cassette units using a thermoelectric cooling system, a prototype designed and manufactured in the laboratory was studied on a testing stand.Result. The directions of constructive solutions for using a TECS device are presented along with a description of the testing stand and procedure. The dependencies of the temperature of the printed circuit board simulator on the heat power taken away by the TECS are considered along with the temperatures of hot and cold junctions, the air flow velocity and the distance between the electronic boards.Conclusion. The operability of the developed MEE cooling system is confirmed by the experimental studies; the specified cooling method has advantages over conventional forced or natural method and can achieve the temperatures required by the technical operating conditions; when choosing a fan to provide forced circulation of the air flow in the system, it is necessary to take into account the speed of the air flow in the channel; it is necessary to reserve the power of the power supply for the TECS operation in proportion to the power of the heat sources. An important additional point for the functioning of the thermoelectric cooling device is the necessity of ensuring the effective removal of heat from the hot junctions of the thermoelectric module without which it is impossible to use the proposed system. 

Numerical Analysis of Oil Immersion Cooling on a Server Using Al2o3/mineral Oil Nanofluid

2021 ◽  
Author(s):  
Amirreza Niazmand ◽  
Prajwal Murthy ◽  
Satyam Saini ◽  
Pardeep Shahi ◽  
Pratik Bansode ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Mineral Oil ◽  
Immersion Cooling ◽  
Oil Immersion
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