Design and Verification of Cray XT- 4 Supercomputer Cooling System

2007 ◽  
Author(s):  
Alexander Yatskov
Keyword(s):  
Power Density ◽  
Cooling System ◽  
Electrical Power ◽  
Cost Effective ◽  
Thermal Design ◽  
Heat Sinks ◽  
The Past ◽  
Design Requirements ◽  
Supercomputer Systems ◽  
Dual Core

Cray supercomputers are purpose-built to meet the special needs of capability class HPC applications. Recent advances in Cray scalar supercomputer systems resulted in the introduction of the higher density compute cabinet that consumes significant amounts of electrical power and produces an extraordinary amount of heat. Due to the new design requirements, which have tremendous consequences with regard to thermal management, new cooling concepts were required. The XT4 can have up to 30,000 dual-core Opterons, and the SeaStar2 interconnection chip plugs right into the Hyper Transport links on the Opteron processors to make a very fast mesh of processors and memory for applications. Such a machine consumes about 5.2 megawatts of power to deliver around 1.15 petaflops. That is twice the size of Red Storm, but more than a factor of 10 more performance. The extra power density required additional modification to the cooling system. This article describes the design, simulations and verification of the XT-3 and XT-4 systems. Over the past few years thermal design for cooling microprocessors has become increasingly challenging, as silicon technology continues to scale in accordance with Moore’s law. The industry has traditionally relied on gradual improvements in air cooled, solid metal heat sinks to keep pace with change in microprocessor design to provide cost effective solution for removing from microprocessors. In Cray’s XT-4 system, chip power density is expected to almost double that of it’s Red Storm/XT-3 predecessors, while maintaining the same cabinet size.

Regulatory and sustainability initiatives lead to improved polyaminopolyamide epichlorohydrin (PAE) wet-strength resins and paper products

TAPPI Journal ◽  
2018 ◽  
Vol 17 (09) ◽  
pp. 519-532 ◽  
Author(s):  
Mark Crisp ◽  
Richard Riehle
Keyword(s):  
Health And Safety ◽  
Cost Effective ◽  
Worker Safety ◽  
Regulatory Requirements ◽  
Wet Strength ◽  
The Past ◽  
Consumer Safety ◽  
Federal Institute ◽  
Sustainability Initiatives ◽  
The Impact

Polyaminopolyamide-epichlorohydrin (PAE) resins are the predominant commercial products used to manufacture wet-strengthened paper products for grades requiring wet-strength permanence. Since their development in the late 1950s, the first generation (G1) resins have proven to be one of the most cost-effective technologies available to provide wet strength to paper. Throughout the past three decades, regulatory directives and sustainability initiatives from various organizations have driven the development of cleaner and safer PAE resins and paper products. Early efforts in this area focused on improving worker safety and reducing the impact of PAE resins on the environment. These efforts led to the development of resins containing significantly reduced levels of 1,3-dichloro-2-propanol (1,3-DCP) and 3-monochloropropane-1,2-diol (3-MCPD), potentially carcinogenic byproducts formed during the manufacturing process of PAE resins. As the levels of these byproducts decreased, the environmental, health, and safety (EH&S) profile of PAE resins and paper products improved. Recent initiatives from major retailers are focusing on product ingredient transparency and quality, thus encouraging the development of safer product formulations while maintaining performance. PAE resin research over the past 20 years has been directed toward regulatory requirements to improve consumer safety and minimize exposure to potentially carcinogenic materials found in various paper products. One of the best known regulatory requirements is the recommendations of the German Federal Institute for Risk Assessment (BfR), which defines the levels of 1,3-DCP and 3-MCPD that can be extracted by water from various food contact grades of paper. These criteria led to the development of third generation (G3) products that contain very low levels of 1,3-DCP (typically <10 parts per million in the as-received/delivered resin). This paper outlines the PAE resin chemical contributors to adsorbable organic halogens and 3-MCPD in paper and provides recommendations for the use of each PAE resin product generation (G1, G1.5, G2, G2.5, and G3).

scholarly journals Near-field thermophotovoltaics for efficient heat to electricity conversion at high power density

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rohith Mittapally ◽  
Byungjun Lee ◽  
Linxiao Zhu ◽  
Amin Reihani ◽  
Ju Won Lim ◽  
...  
Keyword(s):  
Power Density ◽  
High Power ◽  
High Efficiency ◽  
Near Field ◽  
Electrical Power ◽  
Photovoltaic Cells ◽  
High Power Density ◽  
Pv Cell ◽  
Electrical Power Output ◽  
Power Densities

AbstractThermophotovoltaic approaches that take advantage of near-field evanescent modes are being actively explored due to their potential for high-power density and high-efficiency energy conversion. However, progress towards functional near-field thermophotovoltaic devices has been limited by challenges in creating thermally robust planar emitters and photovoltaic cells designed for near-field thermal radiation. Here, we demonstrate record power densities of ~5 kW/m2 at an efficiency of 6.8%, where the efficiency of the system is defined as the ratio of the electrical power output of the PV cell to the radiative heat transfer from the emitter to the PV cell. This was accomplished by developing novel emitter devices that can sustain temperatures as high as 1270 K and positioning them into the near-field (<100 nm) of custom-fabricated InGaAs-based thin film photovoltaic cells. In addition to demonstrating efficient heat-to-electricity conversion at high power density, we report the performance of thermophotovoltaic devices across a range of emitter temperatures (~800 K–1270 K) and gap sizes (70 nm–7 µm). The methods and insights achieved in this work represent a critical step towards understanding the fundamental principles of harvesting thermal energy in the near-field.

A recent overview on the porphyrin-based π-extended small molecules as donors and acceptors for high-performance organic solar cells

2021 ◽  
Author(s):  
Venkatesh Piradi ◽  
Feng Yan ◽  
Xunjin Zhu ◽  
Wai-Yeung Raymond Wong
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Small Molecules ◽  
Organic Solar Cells ◽  
High Performance ◽  
Cost Effective ◽  
Effective Alternative ◽  
The Past ◽  
Cost Effective Alternative ◽  
Silicon Based

Organic solar cells (OSCs) have been considered as a promising cost-effective alternative to silicon-based solar cell counterparts due to their lightweight, mechanical flexibility, and easy fabrication features. Over the past...

scholarly journals Introduction to the Special Issue on New Longitudinal Data for Retirement Analysis and Policy

2021 ◽  
pp. 1-5
Author(s):  
Marco Angrisani ◽  
Anya Samek ◽  
Arie Kapteyn
Keyword(s):  
Big Data ◽  
Academic Research ◽  
Cost Effective ◽  
Research Data ◽  
Data Sources ◽  
Special Issue ◽  
Administrative Records ◽  
The Past ◽  
Survey Questionnaires ◽  
Internet Panels

The number of data sources available for academic research on retirement economics and policy has increased rapidly in the past two decades. Data quality and comparability across studies have also improved considerably, with survey questionnaires progressively converging towards common ways of eliciting the same measurable concepts. Probability-based Internet panels have become a more accepted and recognized tool to obtain research data, allowing for fast, flexible, and cost-effective data collection compared to more traditional modes such as in-person and phone interviews. In an era of big data, academic research has also increasingly been able to access administrative records (e.g., Kostøl and Mogstad, 2014; Cesarini et al., 2016), private-sector financial records (e.g., Gelman et al., 2014), and administrative data married with surveys (Ameriks et al., 2020), to answer questions that could not be successfully tackled otherwise.

High-Power Operation of Acoustic-Electric Power Feedthroughs Through Thick Metallic Barriers

2012 ◽  
Author(s):  
K. R. Wilt ◽  
H. A. Scarton ◽  
G. J. Saulnier ◽  
T. J. Lawry ◽  
J. D. Ashdown
Keyword(s):  
Power Density ◽  
High Power ◽  
Electrical Power ◽  
Power Transfer ◽  
Receive Transducer ◽  
High Power Operation ◽  
Linear Effects ◽  
Power Limits ◽  
Power Operation ◽  
Power Testing

Throughout the last few years there has been a significant push to develop a means for the transmission of electrical power through solid metallic walls using ultrasonic means. The bulk of this effort has been focused on using two coaxially aligned piezoelectric transducers on opposite sides of a thick metallic transmission barrier, where one transducer serves as the “transmit” transducer and the other as the “receive” transducer. Previous modeling has predicted reasonably high power transfer efficiencies through the wall using this type of “acoustic-electric channel” to be possible at low power levels, which implies that channel component operates in a linear range with little concern of failure. High-power testing of two acoustic-electric channels has been done in an effort to determine power limits on such channels and to determine levels at which non-linear effects on the piezoelectrics become non-negligible. The tested channels are characterized by the “power density” imposed on the transmit transducer, that is, the power applied per unit area, as the values found for maximum power density are considered to be independent of transducer radii. The constructed channels are shown to be capable of transmitting large amounts of power (over 100 watts) without failure; and further, extrapolation of the results to channels with larger diameter transducers predicts power transfer of 1 kW to be highly feasible.

scholarly journals Co-Design of CVT-Based Electric Vehicles

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1825
Author(s):  
Caiyang Wei ◽  
Theo Hofman ◽  
Esin Ilhan Caarls
Keyword(s):  
Cooling System ◽  
Design Method ◽  
Low Cost ◽  
Cost Effective ◽  
Speed Ratio ◽  
Air Flow Rate ◽  
Cost Of Ownership ◽  
Variable Transmission ◽  
Primary Focus ◽  
Design Freedom

For an electric vehicle (EV) with a continuously variable transmission (CVT), a novel convex programming (CP)-based co-design method is proposed to minimize the total-cost-of-ownership (TCO). The integration of the electric machine (EM) and the CVT is the primary focus. The optimized system with co-design reduces the TCO by around 5.9% compared to a non-optimized CVT-based EV (based on off-the-shelf components) and by around 2% compared to the EV equipped with a single-speed transmission (SST). By taking advantage of the control and design freedom provided by the CVT, the optimal CVT, EM and battery sizes are found to reduce the system cost. It simultaneously finds the optimal CVT speed ratio and air-flow rate of the cooling system reducing the energy consumption. The strength of co-design is highlighted by comparing to a sequential design, and insights into the design of a low-power EV that is energy-efficient and cost-effective for urban driving are provided. A highly integrated EM-CVT system, which is efficient, low-cost and lightweight, can be expected for future EV applications.

Requirements Capture for Inclusive Design Resources and Tools

Volume 3 ◽  
2004 ◽  
Author(s):  
Hua Dong ◽  
P. John Clarkson ◽  
Simeon Keates
Keyword(s):  
Unmet Needs ◽  
Fundamental Problem ◽  
Inclusive Design ◽  
Planning Stage ◽  
Product Planning ◽  
The Past ◽  
Design Resources ◽  
User Data ◽  
Design Requirements ◽  
The Impact

In the past twenty years, a number of resources and tools to support inclusive design have been developed. However, the impact of these resources and tools on industry is not evident — few industrialists have been using them in practice. Investigations into industry have identified unmet needs, for example, the lack of appropriate user data relating to inclusive design. The fundamental problem is that few resources and tools have been developed based on rigorous requirements capture. In fact, many of them were developed only because the developers think the information could be useful. It is essential to prepare a detailed requirements list when clarifying the task at the product planning stage. This is also true for developing resources and tools for inclusive design. Requirements capture plays an important role in identifying real needs from users and developing appropriate methods of support for them. This paper starts with a survey of available resources and tools for inclusive design, and a discussion on their merits and deficiencies in respect to industry application. A number of methods are employed for the requirements capture for an inclusive design toolkit, which leads to a consistent result. An outline of the toolkit is also presented.

Thermal Analysis of Cooling System in a Gas Turbine Transition Piece

2011 ◽  
Author(s):  
Jun Su Park ◽  
Namgeon Yun ◽  
Hokyu Moon ◽  
Kyung Min Kim ◽  
Sin-Ho Kang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Thermal Stresses ◽  
Cooling System ◽  
Structural Information ◽  
Thermal Analyses ◽  
Thermal Design ◽  
Transfer Coefficients ◽  
Transition Piece ◽  
Inlet Conditions

This paper presents thermal analyses of the cooling system of a transition piece, which is one of the primary hot components in a gas turbine engine. The thermal analyses include heat transfer distributions induced by heat and fluid flow, temperature, and thermal stresses. The purpose of this study is to provide basic thermal and structural information on transition piece, to facilitate their maintenance and repair. The study is carried out primarily by numerical methods, using the commercial software, Fluent and ANSYS. First, the combustion field in a combustion liner with nine fuel nozzles is analyzed to determine the inlet conditions of a transition piece. Using the results of this analysis, pressure distributions inside a transition piece are calculated. The outside of the transition piece in a dump diffuser system is also analyzed. Information on the pressure differences is then used to obtain data on cooling channel flow (one of the methods for cooling a transition piece). The cooling channels have exit holes that function as film-cooling holes. Thermal and flow analyses are carried out on the inside of a film-cooled transition piece. The results are used to investigate the adjacent temperatures and wall heat transfer coefficients inside the transition piece. Overall temperature and thermal stress distributions of the transition piece are obtained. These results will provide a direction to improve thermal design of transition piece.

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