Measurement of the Thermal Performance of a Single-Phase Immersion Cooled Server at Elevated Temperatures for Prolonged Time

2018 ◽  
Author(s):  
Pratik V. Bansode ◽  
Jimil M. Shah ◽  
Gautam Gupta ◽  
Dereje Agonafer ◽  
Harsh Patel ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Single Phase ◽  
Elevated Temperatures ◽  
Operating Cost ◽  
Failure Criteria ◽  
Climatic Conditions ◽  
Temperature Cycling ◽  
Dielectric Fluid ◽  
Air Cooling ◽  
Power Draw

Fully immersion of servers in electrically nonconductive (dielectric) fluid has recently become a promising technique for minimizing cooling energy consumption in data centers. The improved thermal properties of these dielectric fluids facilitate considerable savings in both upfront and operating cost over traditional air-cooling. This technology provides an opportunity for accommodating increased power densities. It also minimizes the common operational issues of air cooling technique like overheating and temperature swing in the system, fan failures, dust, air quality, and corrosion. This paper presents various data about the thermal performance of a fully single-phase dielectric fluid immersed server over wide temperature ranges (environment temperatures) from 25°C to 55°C for prolonged periods in an environmental chamber. This work explores the effects of high temperatures on the performance of a server and other components like pump, along with potential issues associated with extreme climatic conditions. The experimental data serves as a means to determine failure criteria for the server and pump by subjecting the system to accelerated thermal aging conditions i.e. around 55°C, consequently simulating the most extreme environmental condition that the server may encounter. Connector seals are inspected for expected degradation upon temperature cycling typically at such extreme conditions. Throttling limit for the server and pump power draw for different temperatures was determined to assess pump performance. Determining the relations between component behavior and operating temperature provides an accurate measure of lifetime of a server. The scope of this paper can be expanded by reviewing the effects of low temperatures on server and component performance. Changes to various performance parameters like power draw of pump and server at the higher and the lower operating temperatures and an understanding of issues like condensation can be used to quantify upper and lower limits for pump and server performance.

Measurement of the Thermal Performance of a Custom-Build Single-Phase Immersion Cooled Server at Various High and Low Temperatures for Prolonged Time

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Pratik V. Bansode ◽  
Jimil M. Shah ◽  
Gautam Gupta ◽  
Dereje Agonafer ◽  
Harsh Patel ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Single Phase ◽  
Data Centers ◽  
Operating Cost ◽  
Climatic Conditions ◽  
Junction Temperature ◽  
Dielectric Fluid ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Environmental Chamber

Abstract The next radical change in the thermal management of data centers is to shift from conventional cooling methods like air-cooling to direct liquid cooling to enable high thermal mass and corresponding superior cooling. There has been in the past few years a limited adoption of direct liquid cooling in data centers because of its simplicity and high heat dissipation capacity. Single-phase engineered fluid immersion cooling has several other benefits like better server performance, even temperature profile, and higher rack densities and the ability to cool all components in a server without the need for electrical isolation. The reliability aspect of such cooling technology has not been well addressed in the open literature. This paper presents the performance of a fully single-phase dielectric fluid immersed server over wide temperature ranges in an environmental chamber. The server was placed in an environmental chamber and applied extreme temperatures ranging from −20 °C to 10 °C at 100% relative humidity and from 20 to 55 °C at constant 50% relative humidity for extended durations. This work is a first attempt of measuring the performance of a server and other components like pump including flow rate drop, starting trouble, and other potential issues under extreme climatic conditions for a completely liquid-submerged system. Pumping power consumption is directly proportional to the operating cost of a data center. The experiment was carried out until the core temperature reached the maximum junction temperature. This experiment helps to determine the threshold capacity and the robustness of the server for its applications in extreme climatic conditions.

Computational Analysis for Thermal Optimization of Server for Single Phase Immersion Cooling

2019 ◽  
Author(s):  
Dhruvkumar Gandhi ◽  
Uschas Chowdhury ◽  
Tushar Chauhan ◽  
Pratik Bansode ◽  
Satyam Saini ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Single Phase ◽  
Data Centers ◽  
Dielectric Fluid ◽  
Air Cooling ◽  
Processing Unit ◽  
Input Output ◽  
Dielectric Fluids ◽  
Immersion Cooling ◽  
Oil Immersion

Abstract Complete immersion of servers in synthetic dielectric fluids is rapidly becoming a popular technique to minimize the energy consumed by data centers for cooling purposes. In general, immersion cooling offers noteworthy advantages over conventional air-cooling methods as synthetic dielectric fluids have high heat dissipation capacities which are roughly about 1200 times greater than air. Other advantages of dielectric fluid immersion cooling include even thermal profile on chips, reduction in noise and addressing reliability and operational enhancements like whisker formation and electrochemical migration. Nevertheless, lack of data published and availability of long-term reliability data on immersion cooling is insufficient which makes most of data centers operators reluctant to implement this technique. The first part of this paper will compare thermal performance of single-phase oil immersion cooled HP ProLiant DL160 G6 server against air cooled server using computational fluid dynamics on 6SigmaET®. Focus of the study are major components of the server like Central Processing Unit (CPU), Dual in Line Memory Module (DIMM), Input/output Hub (IOH) chip and Input/output controller Hub (ICH). The second part of this paper focuses on thermal performance optimization of oil immersion cooled servers by varying inlet oil temperature, flow rate and using different fluid.

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.

Experimental Analysis for Optimization of Thermal Performance of a Server in Single Phase Immersion Cooling

2019 ◽  
Author(s):  
Pravin A. Shinde ◽  
Pratik V. Bansode ◽  
Satyam Saini ◽  
Rajesh Kasukurthy ◽  
Tushar Chauhan ◽  
...  
Keyword(s):  
Power Consumption ◽  
Thermal Performance ◽  
Heat Dissipation ◽  
Operating Cost ◽  
Heat Removal ◽  
Dielectric Fluid ◽  
Inlet Temperature ◽  
Processing Unit ◽  
Central Processing ◽  
Immersion Cooling

Abstract Liquid immersion cooling of servers in synthetic dielectric fluids is an emerging technology which offers significant cooling energy savings and increased power densities for data centers. A noteworthy advantage of using immersion cooling is high heat dissipation capacity which is roughly 1200 times greater than air. Other advantages of dielectric fluid immersion cooling include high rack density, better server performance, even temperature profile, reduction in noise etc. The enhanced thermal properties of oil lead to the considerable savings in both upfront and operating cost over traditional methods. In this study, a server is completely submerged in a synthetic dielectric fluid. Experiments are conducted to observe the effects of varying the volumetric flow rate and oil inlet temperature on thermal performance and power consumption of the server. Various parameters like total server power consumption, the temperature of all heat generating components like Central Processing Unit (CPU), Dual in Line Memory Module (DIMM), input/output hub (IOH) chip, Platform Controller Hub (PCH), Network Interface Controller (NIC) are measured at steady state. Since this is an air-cooled server, the results obtained from the experiments will help in proposing better heat removal strategies like heat sink optimization, better ducting and server architecture. Assessment has been made on the effect of thermal shadowing caused by the two CPUs on the nearby components like DIMMs and PCH.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

scholarly journals Evidence of Martensitic Transformation in Fe-Mn-Al Steel Similar to Maraging Steel

2020 ◽  
Vol 52 (1) ◽  
pp. 26-33
Author(s):  
Gurumayum Robert Kenedy ◽  
Yi-Jyun Lin ◽  
Wei-Chun Cheng
Keyword(s):  
Martensitic Transformation ◽  
Maraging Steel ◽  
Trip Steel ◽  
Single Phase ◽  
Lath Martensite ◽  
Al Alloy ◽  
Air Cooling ◽  
Small Temperature Gradient ◽  
Austenite Grains ◽  
Equilibrium Phases

AbstractThe Fe-Mn-Al steels claim a low density, and some fall into the category of transformation-induced plasticity (TRIP) steel. In Fe-Mn-Al TRIP steel development, phase transformations play an important role. Herein, the martensitic transformation of an Fe-16.7 Mn-3.4 Al ternary alloy (wt pct) was experimentally discovered, whose equilibrium phases are a single phase of austenite at 1373 K and dual phases of ferrite and austenite at low temperature. Ferritic lath martensite forms in the prior austenite grains after cooling from 1373 K under various cooling rates via quenching, air cooling, and furnace cooling. The formation mechanism of the ferritic lath martensite is different from that of traditional ferritic lath martensite in steel and quite similar to that in maraging steel. A slight strain energy coupled with a small temperature gradient can lead to the formation of ferritic lath martensite in the Fe-Mn-Al alloy after cooling from high temperature. It is also found that micro-twins exist in the ferritic lath martensite.

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