www . refrigerationandaircon . co . za RACA Journal I May 2024 19
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• Water consumption and energy efficiency : Adjusting the setpoints and increasing the facility water temperature resulted in notable water savings , a 20 % reduction in water usage was observed by using a 30 % valve position compared to 50 %. The experiment showcased a crucial outcome : CPU performance remained optimal even at higher server inlet temperatures , allowing for potential adaptation to liquid cooling .
• Implications for GPU-based clusters : The positive results from the study open avenues for deploying additional GPU ( graphics processing unit ) based clusters using liquid cooling to support advanced AI ( artificial intelligence ), HPC and research initiatives within the lab . The decrease in energy consumption , coupled with higher chilled water temperatures , contributes to improved PUE and energy savings , estimated at around 40 %.
The case study serves as a practical exploration into the adaptability of data centres to liquid cooling technologies . It not only showcases the resilience of CPU performance under varying conditions but also provides a foundation for the integration of liquid cooling solutions to meet the demands of evolving high-performance computing workloads . The findings underscore the potential for enhanced energy efficiency and sustainability through the strategic implementation of liquid cooling technologies in data centre environments .
EXAMINING GPU AND CPU DESIGNS , LIQUID COOLING AND THE NEXT TECHNOLOGICAL FRONTIERS On the question about the evolution of chip architecture and how cooling will adapt , the trajectory is towards more advanced and densely packed chip designs . The advent of chiplets , 2.5D and 3D stacking , and heterogeneous integration are all shaping the future of chip architectures . These advancements come with specific thermal challenges , as different components within a package may have varying junction temperature requirements .
The traditional approach of air cooling , where a cold plate or liquid-cooled heatsink is installed on top of the package , may face limitations in efficiently managing the heat generated by these sophisticated chip architectures . The evolving designs call for innovative cooling solutions that can bring the liquid closer to the heat-generating die . This approach helps minimise thermal resistance and ensures effective cooling of the entire package .
Moreover , liquid cooling , with its superior heat-carrying capacity compared to air , becomes a crucial element in addressing the thermal challenges associated with advanced chip architectures . By leveraging the efficiency of liquid cooling , data centres can stay ahead in adapting to the evolving landscape of chip technologies , supporting increased power densities and optimising overall performance .
The prevailing sentiment was uncertainty , with participants acknowledging the challenges of predicting the future . The conversation centred around the implications of extending Moore ' s Law , exploring the idea of incorporating more transistors into existing integrated circuits and adding parallel cores to enhance computing capabilities .
The conversation referenced ongoing deployments with major supercomputing manufacturers , emphasising the strategic shift of electronic components closer to the heatsink . This move aims to maximise heat dissipation from CPUs and associated heat-generating devices , reducing reliance on traditional air-cooling methods .
Shelnutt addressed the question of whether liquid cooling can keep pace with the escalating demands of HPC . While acknowledging the absence of a crystal ball for predicting the future , the focus was on identifying key thermal challenges .
Historically , the temperature drop between a CPU and heatsink was deemed relatively insignificant during air cooling . However , with the advent of high heat transfer co-efficients in singlephase and two-phase cold plates , the discussion emphasised the need to bring cooling fluids into closer contact with generating components . The consensus was that liquid cooling , which has evolved significantly in the past decade , is now poised to surpass traditional air-cooled solutions .
The panellists engaged in a forward-looking dialogue on the next technological frontiers beyond immersion and direct chip cooling . The consensus was that the roadmap should involve removing layers of thermal resistance , envisioning solutions where the liquid or coolant becomes an integral part of the heat spreader . Proposals included exploring embedded cooling technologies , microfluidics and other innovative approaches to minimise thermal resistances . While proprietary solutions may emerge , the panellists expressed excitement about the evolving problem statements in thermal engineering . The challenges ahead are seen as opportunities for innovation , sparking interest in solving complex formulas and pushing the boundaries of current technologies .
Latif highlighted the sustainability aspect of liquid cooling , emphasising ongoing research to enhance the efficiency of immersion liquids . Sustainable manufacturing processes for cooling fluids and environmentally friendly liquid compositions are anticipated to play a crucial role in the future . The focus extended to cold plate design , with an emphasis on materials offering the lowest thermal resistivity . The conversation underscored the pivotal role of both liquid cooling and materials in setting future trends for the industry .
As the discussion concluded , the participants acknowledged that the future of liquid cooling in high performance computing looks promising . Latif touched on the rising production levels of liquid cooling systems and the anticipated higher adoption in the coming days . RACA
www . refrigerationandaircon . co . za RACA Journal I May 2024 19