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 5 of a nine-part series.
Motherboard elements still rely on traditional air cooling. Image by Rawpixel/Freepik.com
Quirk further elaborated on the infrastructural complexities arising from this hybrid approach. He highlighted the distinction between the conductive interface (cold plates) and immersion cooling, reiterating that the current discussion primarily revolves around cold plate applications. He underscored the point that even in advanced liquid-cooled setups, a substantial portion of the heat rejection still relies on air.
The conversation then shifted to the challenges introduced by the increasing number of stakeholders involved in modern data centre deployments. Quirk used the analogy of ‘control boundaries’ in engineering to illustrate this point. In traditional air-cooled environments, the control boundary was relatively clear-cut: the IT racks and servers were the domain of the IT department, while the cooling infrastructure was managed by the data centre operator. However, liquid-to-chip cooling blurs these lines, creating a physical interconnection with liquid piping directly linking the cooling infrastructure to the server racks. This necessitates a far greater degree of collaboration and shared responsibility between IT and facilities teams, a fundamental shift where, as Quirk noted, “the IT guys are now part of the commissioning group”.
This interconnectedness becomes particularly complex in colocation facilities, where the data centre provider builds and operates the infrastructure for various tenants, often including hyperscalers and enterprises. The ownership, operation, testing, commissioning, design and ultimate liability for different components – the CDUs, the TCS piping system, the servers and the racks – can vary significantly from project to project. This lack of clear boundaries and shared responsibility creates significant challenges in ensuring seamless integration and operation. Demetriou added that colocation providers face the added complexity of supporting diverse IT equipment from multiple vendors, each with potentially different water quality and material compatibility requirements, making standardisation at the facility level even more critical.
This multi-stakeholder environment, as Seter pointed out, underscores the vital role of ASHRAE in driving industry consistency and standardisation through publications like the latest technical bulletins and the S-class temperature guidelines. However, he noted that the adoption of these relatively new standards across the industry is still lagging. Furthermore, the involvement of multiple parties, each with their own contractual obligations and safety margins, often leads to inefficiencies in the overall design. Hardware manufacturers might specify wide inlet temperature ranges, but IT operators running specific high-performance workloads might demand much lower temperatures with significant safety buffers. Colocation providers, in turn, might further lower their operational limits to avoid violating service level agreements, and design engineers have to accommodate these compounded safety factors. This cascade of precautionary measures ultimately drives energy inefficiency.
The panel concluded this segment by emphasizing the critical importance of industry-wide standardisation, driven by ASHRAE’s research projects and publications, to bridge the gaps between different stakeholders, reduce unnecessary safety margins, and improve the overall efficiency and reliability of liquid-cooled data centre deployments. While acknowledging that there is still a long way to go, they highlighted the crucial role of platforms like the ASHRAE podcast in disseminating this vital information and fostering a more collaborative and standardised approach across the industry.
