A new briefing paper shares insight into China's experience with the application of liquid-cooling technology to improve datacentres' energy efficiency and environmental sustainability. The brief shares case studies of Alibaba and Tencent's innovations in liquid cooling, provides an overview of technical options in liquid cooling deployment, and highlights the key issues at play in efforts to introduce liquid cooling at greater scale in China and globally.
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The brief on liquid cooling in China was developed by the Copenhagen Centre on Energy Efficiency with the support of China's Open Data Center Committee and ITU. The Copenhagen Centre is part of the UNEP DTU partnership, a collaboration supported by the UN Environment Programme (UNEP), the Danish Ministry of Foreign Affairs and the Technical University of Denmark (DTU).
The brief is the fourth in a series of Copenhagen Centre briefs on datacentres, following briefs on lifecycle environmental impacts of datacentres, the case for energy-efficient datacentres, and reducing the energy use of video gaming.
ITU standardization work on energy efficiency is led by ITU-T Study Group 5 (Environment and circular economy) and datacentres form a key area of focus for the group. One of the latest ITU standards in this domain – ITU L.1305 'Specifications of datacentre infrastructure management (DCIM) system based on Big Data and Artificial Intelligence technology' – supports DCIM systems in reducing the energy required to control datacentre temperature.
Approaching the limits of air cooling
China's datacentre market has been growing at an annual rate of around 30 per cent since 2012, reports the China Academy of Information and Communications Technology.
Cloud computing, AI and big data are among the megatrends stimulating the growth of the datacentre market. Increases in chip density and computing complexity have created a steady rise in the heat load of computing equipment. Air cooling's ability to meet this increased demand for heat dissipation is approaching its limit, highlights the brief.
Liquid-cooling technology has long been applied by the aerospace industry, for example in satellites and rocket engines. The technology is finding new application in datacentres thanks to its large heat capacity and efficient heat dissipation, ability to reduce energy consumption and expenditure, and considerable potential to advance climate action.
The brief also notes other advantages of liquid cooling in reducing the physical space required by computing equipment and increasing the reliability of this equipment as well as its lifespan.
Liquid cooling at Alibaba and Tencent
The brief describes three prominent liquid-cooling technologies in cold-plate liquid cooling, immersion liquid cooling, and spray liquid cooling.
It shares the example of immersion liquid cooling in Alibaba's Winter Olympics Cloud Data Centre, an example demonstrating energy savings of 35 per cent relative to an air-cooled datacentre of comparable size.
The brief makes use of the Alibaba example to illustrate the benefits for the climate: running 100,000 liquid-cooled as opposed to air-cooled servers would reduce electricity consumption by 235 million kilowatt hours each year, with an associated annual reduction of 200,000 tons of carbon dioxide emissions.
Tencent's cold-plate liquid cooling solution employs a combination of liquid cooling and micro modules that comes in tandem with the ability to exploit the advantages of modularization. The solution is said to possess the flexibility and speed of deployment necessitated by the explosive growth of the datacentre business.
A revolution reliant on standards
The brief concludes that liquid-cooling technology could constitute a revolution in datacentre cooling, but that this revolution will rely on datacentre transformations requiring substantial investment and the accumulation of new experience in operations and maintenance.
Cooperation nationally and globally, notes the brief, could make a key contribution to the development of the industry value chain for liquid cooling and the growth of a global market.
It highlights the need for technical standards to support the development of liquid-cooling technology and its application at scale, noting that standards could bring more cohesion to research and development by establishing clear technical requirements for the involved liquids, power supply and distribution, control, security, and operations and maintenance.
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