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!

ASC18: Final Results Revealed & Wrapped Up

May 17, 2018

It was an exciting week at ASC18 in Nanyang, China. The student teams braved extreme heat, extremely difficult applications, and extreme competition in order to cross the cluster competition finish line. The gala awards ceremony took place on Wednesday. The auditorium was packed with student teams, various dignitaries, the media, and other interested parties. So what happened? Read more…

By Dan Olds

ASC18: Tough Applications & Tough Luck

May 17, 2018

The applications at the ASC18 Student Cluster Competition were tough. Tougher than the $3.99 steak special at your local greasy spoon restaurant. The apps are so tough that even Chuck Norris backs away from them slowly. Read more…

By Dan Olds

Spring Meetings Underscore Quantum Computing’s Rise

May 17, 2018

The month of April 2018 saw four very important and interesting meetings to discuss the state of quantum computing technologies, their potential impacts, and the technology challenges ahead. These discussions happened in Read more…

By Alex R. Larzelere

HPE Extreme Performance Solutions

HPC and AI Convergence is Accelerating New Levels of Intelligence

Data analytics is the most valuable tool in the digital marketplace – so much so that organizations are employing high performance computing (HPC) capabilities to rapidly collect, share, and analyze endless streams of data. Read more…

IBM Accelerated Insights

Mastering the Big Data Challenge in Cognitive Healthcare

Patrick Chain, genomics researcher at Los Alamos National Laboratory, posed a question in a recent blog: What if a nurse could swipe a patient’s saliva and run a quick genetic test to determine if the patient’s sore throat was caused by a cold virus or a bacterial infection? Read more…

Quantum Network Hub Opens in Japan

May 17, 2018

Following on the launch of its Q Commercial quantum network last December with 12 industrial and academic partners, the official Japanese hub at Keio University is now open to facilitate the exploration of quantum applications important to science and business. The news comes a week after IBM announced that North Carolina State University was the first U.S. university to join its Q Network. Read more…

By Tiffany Trader

ASC18: Final Results Revealed & Wrapped Up

May 17, 2018

It was an exciting week at ASC18 in Nanyang, China. The student teams braved extreme heat, extremely difficult applications, and extreme competition in order to cross the cluster competition finish line. The gala awards ceremony took place on Wednesday. The auditorium was packed with student teams, various dignitaries, the media, and other interested parties. So what happened? Read more…

By Dan Olds

Spring Meetings Underscore Quantum Computing’s Rise

May 17, 2018

The month of April 2018 saw four very important and interesting meetings to discuss the state of quantum computing technologies, their potential impacts, and th Read more…

By Alex R. Larzelere

Quantum Network Hub Opens in Japan

May 17, 2018

Following on the launch of its Q Commercial quantum network last December with 12 industrial and academic partners, the official Japanese hub at Keio University is now open to facilitate the exploration of quantum applications important to science and business. The news comes a week after IBM announced that North Carolina State University was the first U.S. university to join its Q Network. Read more…

By Tiffany Trader

Democratizing HPC: OSC Releases Version 1.3 of OnDemand

May 16, 2018

Making HPC resources readily available and easier to use for scientists who may have less HPC expertise is an ongoing challenge. Open OnDemand is a project by t Read more…

By John Russell

PRACE 2017 Annual Report: Exascale Aspirations; Industry Collaboration; HPC Training

May 15, 2018

The Partnership for Advanced Computing in Europe (PRACE) today released its annual report showcasing 2017 activities and providing a glimpse into thinking about Read more…

By John Russell

US Forms AI Brain Trust

May 11, 2018

Amid calls for a U.S. strategy for promoting AI development, the Trump administration is forming a senior-level panel to help coordinate government and industry research efforts. The Select Committee on Artificial Intelligence was announced Thursday (May 10) during a White House summit organized by the Office of Science and Technology Policy (OSTP). Read more…

By George Leopold

Emerging Advanced Scale Tech Trends Focus of Annual Tabor Conference

May 9, 2018

At Tabor Communications' annual Advanced Scale Forum (ASF) held this week in Austin, the focus was on enterprise adoption of HPC-class technologies and high performance data analytics (HPDA). It’s a confab that brings together end users (CIOs, IT planners, department heads) and vendors and encourages... Read more…

By the Editorial Team

Google I/O 2018: AI Everywhere; TPU 3.0 Delivers 100+ Petaflops but Requires Liquid Cooling

May 9, 2018

All things AI dominated discussion at yesterday’s opening of Google’s I/O 2018 developers meeting covering much of Google's near-term product roadmap. The e Read more…

By John Russell

MLPerf – Will New Machine Learning Benchmark Help Propel AI Forward?

May 2, 2018

Let the AI benchmarking wars begin. Today, a diverse group from academia and industry – Google, Baidu, Intel, AMD, Harvard, and Stanford among them – releas Read more…

By John Russell

How the Cloud Is Falling Short for HPC

March 15, 2018

The last couple of years have seen cloud computing gradually build some legitimacy within the HPC world, but still the HPC industry lies far behind enterprise I Read more…

By Chris Downing

Russian Nuclear Engineers Caught Cryptomining on Lab Supercomputer

February 12, 2018

Nuclear scientists working at the All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) have been arrested for using lab supercomputing resources to mine crypto-currency, according to a report in Russia’s Interfax News Agency. Read more…

By Tiffany Trader

Inventor Claims to Have Solved Floating Point Error Problem

January 17, 2018

"The decades-old floating point error problem has been solved," proclaims a press release from inventor Alan Jorgensen. The computer scientist has filed for and Read more…

By Tiffany Trader

Researchers Measure Impact of ‘Meltdown’ and ‘Spectre’ Patches on HPC Workloads

January 17, 2018

Computer scientists from the Center for Computational Research, State University of New York (SUNY), University at Buffalo have examined the effect of Meltdown 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

Deep Learning at 15 PFlops Enables Training for Extreme Weather Identification at Scale

March 19, 2018

Petaflop per second deep learning training performance on the NERSC (National Energy Research Scientific Computing Center) Cori supercomputer has given climate Read more…

By Rob Farber

AI Cloud Competition Heats Up: Google’s TPUs, Amazon Building AI Chip

February 12, 2018

Competition in the white hot AI (and public cloud) market pits Google against Amazon this week, with Google offering AI hardware on its cloud platform intended Read more…

By Doug Black

Leading Solution Providers

US Plans $1.8 Billion Spend on DOE Exascale Supercomputing

April 11, 2018

On Monday, the United States Department of Energy announced its intention to procure up to three exascale supercomputers at a cost of up to $1.8 billion with th Read more…

By Tiffany Trader

Lenovo Unveils Warm Water Cooled ThinkSystem SD650 in Rampup to LRZ Install

February 22, 2018

This week Lenovo took the wraps off the ThinkSystem SD650 high-density server with third-generation direct water cooling technology developed in tandem with par Read more…

By Tiffany Trader

HPC and AI – Two Communities Same Future

January 25, 2018

According to Al Gara (Intel Fellow, Data Center Group), high performance computing and artificial intelligence will increasingly intertwine as we transition to Read more…

By Rob Farber

Google Chases Quantum Supremacy with 72-Qubit Processor

March 7, 2018

Google pulled ahead of the pack this week in the race toward "quantum supremacy," with the introduction of a new 72-qubit quantum processor called Bristlecone. Read more…

By Tiffany Trader

HPE Wins $57 Million DoD Supercomputing Contract

February 20, 2018

Hewlett Packard Enterprise (HPE) today revealed details of its massive $57 million HPC contract with the U.S. Department of Defense (DoD). The deal calls for HP Read more…

By Tiffany Trader

CFO Steps down in Executive Shuffle at Supermicro

January 31, 2018

Supermicro yesterday announced senior management shuffling including prominent departures, the completion of an audit linked to its delayed Nasdaq filings, and Read more…

By John Russell

Deep Learning Portends ‘Sea Change’ for Oil and Gas Sector

February 1, 2018

The billowing compute and data demands that spurred the oil and gas industry to be the largest commercial users of high-performance computing are now propelling Read more…

By Tiffany Trader

Nvidia Ups Hardware Game with 16-GPU DGX-2 Server and 18-Port NVSwitch

March 27, 2018

Nvidia unveiled a raft of new products from its annual technology conference in San Jose today, and despite not offering up a new chip architecture, there were still a few surprises in store for HPC hardware aficionados. Read more…

By Tiffany Trader

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