Liquid cooling: decisions, types, approaches.

By Nicole Hemsoth

June 11, 2012

Despite world economic turmoil of the recent severe European crisis, the demand for high performance computing services stays on the rise. Companies and institutions progressively see computational power as a source of competitive advantage and in many cases as the only optimal solution for many scientific and business challenges, from high energy physics to big data. This trend has brought an unprecedented rise in demand for high computational power. This is posing some sound energy and thermal management challenges.

The energy problem in data centres is two sided. On the one hand, data centres have a problem of energy consumption, which enlarges bills also in countries where the cost of energy is relatively low. On the other hand, there is a problem of peak power demand, so, in other words, a problem of availability.  Megawatt installations are not so uncommon anymore, meaning that a request of power similar to the one that has traditionally belonged to the heavy industry sector is becoming almost the norm, in some occasions requiring special arrangement for power systems and electrical lines.

Thermal management is exacerbated by another trend: density. In many cases, rack powers of 30 kW are well beyond what legacy air cooling can handle. In the modern HPC, the high powers in play often leave few options but resorting to some form of water cooling.

Liquid cooling has many advantages, which derive from the much higher heat capacity per unit volume of water compared to air (we are talking about a factor of 3500 times higher). Liquid cooling implies higher densities, energy savings and the possibility to reuse the thermal energy that the water extracts from the IT equipment. Some additional advantages can be found in terms of lower noise levels, less vibrations and close control of electronics temperatures.

The best approach in deciding what type of cooling to implement is to consider alternatives in relation to technical and business needs, the type of air and liquid cooling system available within budget and a series of variables that play an important role in the decision: the desired density versus space availability, new construction versus existing construction, the proximity to natural sources of cold water like rivers and lakes, the local climate, the cost of energy and the thermal energy recovery possibilities.

For instance, high performance high density requirements may leave little choice than liquid cooling to efficiently manage the extraction of the heat from the supercomputers. While, if the data centre has an economizer and the climate is best suited to air-side economizers (mild temperatures and moderate humidity) than an air cooled DC may have more sense. 

Deciding the cooling system may also take in consideration the type of water cooling to be installed. There are solutions that simply create an extension of the existing liquid-cooling loop closer to the IT equipment like in the case of liquid cooled racks (liquid cooled door, closed-liquid rack). In other solutions, in-row units are embedded in rows of data center cabinets, providing localized air distribution and management. Alternatively, overhead cooling suspends from the ceiling complements a hot aisle/cold aisle arrangement. As hot air rises from the hot aisle, the overhead cooler captures it, conditions it, and releases it back to the cold aisle

More effective cooling can be reached when the liquid is brought in the near proximity of the electronic components like in the case of submerged cooling, spray cooling or direct (embedded) cooling.

In the first case, the electronic components are immerged in oil and water which is kept in circulation through small pumps. In the second, the water is vaporized and tiny drops of water fall on the electronics evaporating immediately and taking away a lot of heat. In the latter, water is taken through metal plates or micro pipes to direct contact with processors, memory and other components.

Another distinction is normally made between hot and cold liquid cooling. The definition of hot liquid cooling can be vary. In Eurotech we think that hot liquid cooling means the technology capable of using a liquid (e.g. water) with a temperature above the server room temperature.  We also accept that, pushing the bar up in terms of max coolant temperature, hot liquid cooling may take place when the water is hot enough to allow thermal energy reuse.

In any kind of liquid cooling, one aspect that needs careful attention is the risk of leaking. This is an issue because the electronic components are upgraded on a routine basis resulting in many systems with the need to disconnect and reconnect the liquid carrying lines. Also, there is the need to consider whether cooling with water brings on all of its potential. For instance, resorting to chillers to cool the water will allow density, but limit the energy savings that are maximized with hot water cooling technologies, thanks to air conditioning avoidance. However, it is no news that new powerful processors with TDP of 150W may require coolant temperatures lower that the ones guaranteed by free cooling in warm climates. An additional downside of increasing water temperature may be the higher operating temperature of electronic components.  This risk needs to be balanced by the advantages coming from levelling temperatures on the mother board and avoiding hot spots at data center level.

Eurotech approach

Eurotech has developed liquid cooling systems for more than 7 years and it was the first in the market to offer a hot liquid cooling with high serviceability. Eurotech Aurora supercomputers have been liquid cooled since product one and day one, allowing for precious competences and know how to be waived within the fabric of the organization. This experience helped the development of our idea of liquid cooling.

Eurotech liquid cooling is:

Hot. That means using hot water of 50+ °C, balancing customer needs, density targets, data center temperature and site temperature/humidity profiles. Eurotech delivers to customers the liquid cooling solution that allows utilizing the water at the maximum temperature possible across the year. 

Direct.  The cooling takes place inside the rack, where aluminum cold plates are put in direct contact with the components, allowing to maximize the heat transfer and heat extraction efficacy. The good side effect is to level out temperatures on board avoiding hot spots.

Green. Eurotech aims to utilize free coolers (liquid to air heat exchangers) in any climate zone. Solutions are designed to avoid air conditioning, while maintaining the highest density possible, and to exploit, if required and wherever it is possible, thermal energy recovery.

Comprehensive. The “cold plates” cool processors, memory, FPGAs, power supply, switches and any other heat generating component, including GPUs or other accelerators. This means that there is not a single heat source in the rack that is not cooled, preventing hot spots at DC level.

Serviceable. Eurotech Aurora HPC boards are hot swappable despite being water cooled thanks to connectors that seal instantaneously when a node card is extracted for maintenance or management purposes. The node cards are blades that a single person can easily manage.

Safe. Eurotech understand that it is imperative to keep water away from electronics. For this reason we have spent several years to develop a system that doesn’t leak and to mature those competencies that guide our customers into the correct and trouble free maintenance of the liquid cooling infrastructure.

Indeed, one of the Eurotech focus is on correct liquid cooling operations and maintenance, which is fundamental to preserve the system safety and integrity and keep performances at top levels.

“The maintenance of liquid cooling systems is not a daunting task” says Paul Arts, Eurotech technical director “but it requires following guidelines many of them are conveniently collected by Ashrae. At Eurotech, we assist our customers in approaching hot water cooling, designing the systems and training the customers in operations and maintenance. If have to spare my 2 cents, areas I would focus my attention are water quality, anti-corrosion precautions, flow rate and dew point temperatures”

Eurotech has experienced that correct operations maximize the life not only of the cooling system but also of the electronic components, rounding up the advantages of using hot water cooling. Eurotech believes in liquid cooling as an approachable and concrete solution for facing energy and thermal issues, especially in those contexts that are climatically unfavourable.

http://www.eurotech.com/en/hpc/

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industy updates delivered to you every week!

ASC17 Makes Splash at Wuxi Supercomputing Center

April 24, 2017

A record-breaking twenty student teams plus scores of company representatives, media professionals, staff and student volunteers transformed a formerly empty hall inside the Wuxi Supercomputing Center into a bustling hub of HPC activity, kicking off day one of 2017 Asia Student Supercomputer Challenge (ASC17). Read more…

By Tiffany Trader

Musk’s Latest Startup Eyes Brain-Computer Links

April 21, 2017

Elon Musk, the auto and space entrepreneur and severe critic of artificial intelligence, is forming a new venture that reportedly will seek to develop an interface between the human brain and computers. Read more…

By George Leopold

MIT Mathematician Spins Up 220,000-Core Google Compute Cluster

April 21, 2017

On Thursday, Google announced that MIT math professor and computational number theorist Andrew V. Sutherland had set a record for the largest Google Compute Engine (GCE) job. Sutherland ran the massive mathematics workload on 220,000 GCE cores using preemptible virtual machine instances. Read more…

By Tiffany Trader

NERSC Cori Shows the World How Many-Cores for the Masses Works

April 21, 2017

As its mission, the high performance computing center for the U.S. Department of Energy Office of Science, NERSC (the National Energy Research Supercomputer Center), supports a broad spectrum of forefront scientific research across diverse areas that includes climate, material science, chemistry, fusion energy, high-energy physics and many others. Read more…

By Rob Farber

HPE Extreme Performance Solutions

Remote Visualization Optimizing Life Sciences Operations and Care Delivery

As patients continually demand a better quality of care and increasingly complex workloads challenge healthcare organizations to innovate, investing in the right technologies is key to ensuring growth and success. Read more…

Nvidia P100 Shows 1.3-2.3x Speedup Over K80 GPU on Financial Apps

April 20, 2017

When it comes to the true performance of the latest silicon, every end user knows that the best processor is the one that works best for their application. Read more…

By Tiffany Trader

Quantum Adds Global Smarts to StorNext File System

April 20, 2017

Companies that use Quantum’s StorNext platform to store massive amounts of data this week got a glimpse of new storage capabilities that should make it easier to access their data horde from anywhere in the world. Read more…

By Alex Woodie

Scaling an HPC Career in Nepal Can Be a Steep Climb

April 20, 2017

Umesh Upadhyaya works as an IT Associate at the International Centre for Integrated Mountain Development (ICIMOD) in Nepal, which supports the country’s one and only HPC facility. He is directly involved in an initiative that focuses on climate change and atmosphere modeling Read more…

By Nages Sieslack

Hyperion (IDC) Paints a Bullish Picture of HPC Future

April 20, 2017

Hyperion Research – formerly IDC’s HPC group – yesterday painted a fascinating and complicated portrait of the HPC community’s health and prospects at the HPC User Forum held in Albuquerque, NM. HPC sales are up and growing ($22 billion, all HPC segments, 2016). Read more…

By John Russell

ASC17 Makes Splash at Wuxi Supercomputing Center

April 24, 2017

A record-breaking twenty student teams plus scores of company representatives, media professionals, staff and student volunteers transformed a formerly empty hall inside the Wuxi Supercomputing Center into a bustling hub of HPC activity, kicking off day one of 2017 Asia Student Supercomputer Challenge (ASC17). Read more…

By Tiffany Trader

NERSC Cori Shows the World How Many-Cores for the Masses Works

April 21, 2017

As its mission, the high performance computing center for the U.S. Department of Energy Office of Science, NERSC (the National Energy Research Supercomputer Center), supports a broad spectrum of forefront scientific research across diverse areas that includes climate, material science, chemistry, fusion energy, high-energy physics and many others. Read more…

By Rob Farber

Hyperion (IDC) Paints a Bullish Picture of HPC Future

April 20, 2017

Hyperion Research – formerly IDC’s HPC group – yesterday painted a fascinating and complicated portrait of the HPC community’s health and prospects at the HPC User Forum held in Albuquerque, NM. HPC sales are up and growing ($22 billion, all HPC segments, 2016). Read more…

By John Russell

Knights Landing Processor with Omni-Path Makes Cloud Debut

April 18, 2017

HPC cloud specialist Rescale is partnering with Intel and HPC resource provider R Systems to offer first-ever cloud access to Xeon Phi "Knights Landing" processors. The infrastructure is based on the 68-core Intel Knights Landing processor with integrated Omni-Path fabric (the 7250F Xeon Phi). Read more…

By Tiffany Trader

CERN openlab Explores New CPU/FPGA Processing Solutions

April 14, 2017

Through a CERN openlab project known as the ‘High-Throughput Computing Collaboration,’ researchers are investigating the use of various Intel technologies in data filtering and data acquisition systems. Read more…

By Linda Barney

DOE Supercomputer Achieves Record 45-Qubit Quantum Simulation

April 13, 2017

In order to simulate larger and larger quantum systems and usher in an age of “quantum supremacy,” researchers are stretching the limits of today’s most advanced supercomputers. Read more…

By Tiffany Trader

Penguin Takes a Run at the Big Cloud Providers

April 12, 2017

HPC specialist Penguin Computing recently re-ran benchmarks from a study of its larger brethren and says the results show its ‘public cloud’ – Penguin on Demand (POD) – is among the leaders in cost and performance. Read more…

By John Russell

Nvidia Responds to Google TPU Benchmarking

April 10, 2017

Nvidia highlights strengths of its newest GPU silicon in response to Google's report on the performance and energy advantages of its custom tensor processor. Read more…

By Tiffany Trader

Google Pulls Back the Covers on Its First Machine Learning Chip

April 6, 2017

This week Google released a report detailing the design and performance characteristics of the Tensor Processing Unit (TPU), its custom ASIC for the inference phase of neural networks (NN). Read more…

By Tiffany Trader

Quantum Bits: D-Wave and VW; Google Quantum Lab; IBM Expands Access

March 21, 2017

For a technology that’s usually characterized as far off and in a distant galaxy, quantum computing has been steadily picking up steam. Read more…

By John Russell

Trump Budget Targets NIH, DOE, and EPA; No Mention of NSF

March 16, 2017

President Trump’s proposed U.S. fiscal 2018 budget issued today sharply cuts science spending while bolstering military spending as he promised during the campaign. Read more…

By John Russell

HPC Compiler Company PathScale Seeks Life Raft

March 23, 2017

HPCwire has learned that HPC compiler company PathScale has fallen on difficult times and is asking the community for help or actively seeking a buyer for its assets. Read more…

By Tiffany Trader

Nvidia Responds to Google TPU Benchmarking

April 10, 2017

Nvidia highlights strengths of its newest GPU silicon in response to Google's report on the performance and energy advantages of its custom tensor processor. Read more…

By Tiffany Trader

CPU-based Visualization Positions for Exascale Supercomputing

March 16, 2017

In this contributed perspective piece, Intel’s Jim Jeffers makes the case that CPU-based visualization is now widely adopted and as such is no longer a contrarian view, but is rather an exascale requirement. Read more…

By Jim Jeffers, Principal Engineer and Engineering Leader, Intel

For IBM/OpenPOWER: Success in 2017 = (Volume) Sales

January 11, 2017

To a large degree IBM and the OpenPOWER Foundation have done what they said they would – assembling a substantial and growing ecosystem and bringing Power-based products to market, all in about three years. Read more…

By John Russell

TSUBAME3.0 Points to Future HPE Pascal-NVLink-OPA Server

February 17, 2017

Since our initial coverage of the TSUBAME3.0 supercomputer yesterday, more details have come to light on this innovative project. Of particular interest is a new board design for NVLink-equipped Pascal P100 GPUs that will create another entrant to the space currently occupied by Nvidia's DGX-1 system, IBM's "Minsky" platform and the Supermicro SuperServer (1028GQ-TXR). Read more…

By Tiffany Trader

Leading Solution Providers

Tokyo Tech’s TSUBAME3.0 Will Be First HPE-SGI Super

February 16, 2017

In a press event Friday afternoon local time in Japan, Tokyo Institute of Technology (Tokyo Tech) announced its plans for the TSUBAME3.0 supercomputer, which will be Japan’s “fastest AI supercomputer,” Read more…

By Tiffany Trader

IBM Wants to be “Red Hat” of Deep Learning

January 26, 2017

IBM today announced the addition of TensorFlow and Chainer deep learning frameworks to its PowerAI suite of deep learning tools, which already includes popular offerings such as Caffe, Theano, and Torch. Read more…

By John Russell

Is Liquid Cooling Ready to Go Mainstream?

February 13, 2017

Lost in the frenzy of SC16 was a substantial rise in the number of vendors showing server oriented liquid cooling technologies. Three decades ago liquid cooling was pretty much the exclusive realm of the Cray-2 and IBM mainframe class products. That’s changing. We are now seeing an emergence of x86 class server products with exotic plumbing technology ranging from Direct-to-Chip to servers and storage completely immersed in a dielectric fluid. Read more…

By Steve Campbell

BioTeam’s Berman Charts 2017 HPC Trends in Life Sciences

January 4, 2017

Twenty years ago high performance computing was nearly absent from life sciences. Today it’s used throughout life sciences and biomedical research. Genomics and the data deluge from modern lab instruments are the main drivers, but so is the longer-term desire to perform predictive simulation in support of Precision Medicine (PM). There’s even a specialized life sciences supercomputer, ‘Anton’ from D.E. Shaw Research, and the Pittsburgh Supercomputing Center is standing up its second Anton 2 and actively soliciting project proposals. There’s a lot going on. Read more…

By John Russell

HPC Startup Advances Auto-Parallelization’s Promise

January 23, 2017

The shift from single core to multicore hardware has made finding parallelism in codes more important than ever, but that hasn’t made the task of parallel programming any easier. Read more…

By Tiffany Trader

HPC Technique Propels Deep Learning at Scale

February 21, 2017

Researchers from Baidu’s Silicon Valley AI Lab (SVAIL) have adapted a well-known HPC communication technique to boost the speed and scale of their neural network training and now they are sharing their implementation with the larger deep learning community. Read more…

By Tiffany Trader

US Supercomputing Leaders Tackle the China Question

March 15, 2017

Joint DOE-NSA report responds to the increased global pressures impacting the competitiveness of U.S. supercomputing. Read more…

By Tiffany Trader

IDG to Be Bought by Chinese Investors; IDC to Spin Out HPC Group

January 19, 2017

US-based publishing and investment firm International Data Group, Inc. (IDG) will be acquired by a pair of Chinese investors, China Oceanwide Holdings Group Co., Ltd. Read more…

By Tiffany Trader

  • arrow
  • Click Here for More Headlines
  • arrow
Share This