ShareData centres: the challenges of energy-efficient chip cooling
Innovative liquid cooling solutions are under development to further reduce energy consumption in the ever-growing number of data centres.
Estimated global data centreelectricity consumption in 2022 was, according to the IEA, between 240 and 340 TWh, or around 1-1.3% of global final electricity demand (1).
Since 2010, the number of internet users worldwide has more than doubled, while global internet traffic has expanded 20-fold (1). Strong growth in demand for data network services is expected to continue, driven primarily by data-intensive activities such as video streaming, cloud gaming and augmented and virtual reality applications (1).
In addition, the strong development of digital asset management within the blockchain ecosystem, such as cryptocurrency mining, requires considerable computing power (2).
Furthermore, the potentially exponential development of the uses of artificial intelligence could significantly increase this demand for data-intensive services. Generative AI models such as ChatGPT are bringing artificial intelligence to the masses. Anyone with an internet connection can now use sophisticated deep learning tools to complete complex tasks in a matter of seconds (3). AI-related electricity consumption could thus represent 15-20% of total of data centre consumption in 2028 (4).
However, since 2010, despite this strong growth in demand for digital services, data center energy use (excluding energy used for cryptocurrency mining) has grown only moderately, in part thanks to improvements in the efficiency of IT equipment and their cooling technologies (1).
The exponential growth of data centres in an ever-increasing digital world has led to significant investments in research, particularly in chip cooling. The cooling of microchips — major energy-consuming components in data centres and ever more powerful — can alone account for 40% of overall energy usage in a data centre (5).
Liquid cooling (typically using water), which is more efficient than air cooling, has become the priority option but is only used in 5% of existing data centres. However, the demand for water as a cooling fluid is becoming a widespread problem and organisations are now prioritising water conservation as part of their sustainability efforts.
In the United States, to address these challenges and explore new approaches to chip cooling, the Department of Energy launched the COOLERCHIPS programme. Purdue University, a recipient of a portion of the USD 40 million program, is at the forefront of developing innovative chip cooling solutions.
One of the key research areas at Purdue University involves two-phase jet impingement cooling. This method uses microchannels filled with liquid integrated directly within the microchip packaging. As the chip generates heat, the liquid boils, and the resulting vapours carry the heat away from the chip. The steam then condenses and is recirculated into the chip, enabling passive cooling without the need for a pump.
Another option being explored involves direct liquid contact with the chip's surface, eliminating the need for thermal interface materials. A layer of silicone on the backside further enhances cooling efficiency. By using the gravity of the liquid, Purdue aims to minimise power consumption by placing the condenser at a higher position and allowing gravity to drive the flow into the chips. This approach optimises chip cooling while reducing energy consumption.
Sources:
https://www.iea.org/energy-system/buildings/data-centres-and-data-transmission-networks
https://energypost.eu/will-ai-queries-increase-data-centre-energy-use-by-an-order-of-magnitude/
https://download.schneider-electric.com/files?p_Doc_Ref=SPD_WP110_EN
https://www.datacenterknowledge.com/power-and-cooling/chip-cooling-answer-data-center-sustainability