An ASHRAE podcast recently delved into a critical evolution within data centres: the increasing necessity of liquid cooling. Host Justin Seter guided a panel of industry experts – David Quirk, Dustin Demetriou and Tom Davidson – through the intricacies of this technology, driven by the insatiable demands of artificial intelligence (AI) and high-performance Graphics Processing Unit (GPU) applications. This is Part 1 of a nine-part series.
A central theme of the conversation was the urgent need for standardisation within this rapidly evolving landscape. Image by DCStudio/Freepik.com
The discussion illuminated a significant paradigm shift from traditional air-cooling methods to liquid solutions, a change that has dramatically increased rack power densities from a modest 10-20 kW to an impressive 40-60 kW and even beyond.
A central theme of the conversation was the urgent need for standardisation within this rapidly evolving landscape. The panelists underscored the vital role of ASHRAE’s comprehensive guidelines, including the dedicated liquid cooling book and the extensive data centre encyclopedia, in ensuring both the operational resiliency and energy efficiency of these advanced cooling systems. The discussion also addressed the inherent challenges of seamlessly integrating these new liquid cooling architectures with existing data centre infrastructure, a hurdle that requires careful planning and innovative solutions. Furthermore, the panel highlighted the necessity for developing new, more accurate metrics to effectively measure the efficiency of these novel cooling approaches.
Seter, with nearly two decades in the data centre field and a long-standing ASHRAE member active in both the building commissioning (TC 7.9) and data centre (TC 9.9) technical committees, initiated the discussion by emphasising the timely and crucial nature of the topic. He then invited the panel to introduce themselves and their extensive experience in the field.
Quirk, president and CEO of POB Associates, a nationwide consulting engineering, commissioning and controls company exclusively focused on data centres, brought over 25 years of industry experience to the table. As a past chair and current voting member of ASHRAE TC 9.9, Quirk highlighted the historical context of liquid cooling, noting that while not a new concept – its roots tracing back to mainframe computers – its current scale of deployment, driven by AI, marks a significant turning point. He emphasised how the limitations of air cooling in handling the heat generated by power-hungry GPUs necessitates this shift towards more efficient liquid-based heat transfer. Quirk also recalled his early involvement with direct-to-chip applications through the National Science Foundation and his subsequent deep immersion in the topic through ASHRAE’s liquid cooling book.
Davidson, a senior mechanical engineer also from POB Associates with approximately 25 years dedicated to data centres within his 35-year tenure with the company, echoed Quirk’s sentiments. As a long-term corresponding and voting member of TC 9.9, Davidson brought his extensive practical experience in the evolution of data centre cooling to the conversation.
Demetriou, the current vice chair of the IT subcommittee within ASHRAE TC 9.9 and a former chair of the overarching committee, offered a perspective honed over 15 years specifically focused on data centre energy efficiency, liquid cooling and IT equipment. With a background as a mechanical engineer, Demetriou, also an ASHRAE Distinguished Lecturer and an Uptime Institute accredited sustainability advisor, provided a detailed overview of the different types of liquid cooling solutions currently being deployed.
