www . refrigerationandaircon . co . za RACA Journal I February 2025 19
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Reeves anticipates changes in the weight of immersion-based systems and notes ongoing innovation in fluid technologies with expected gains in efficiency , compatibility and degradation resistance .
Diaz foresees a more competitive market . “ The increasing number of reputable companies entering the fluid market is expected to drive innovation and create a push for efficiency , sustainability and cost-effectiveness . The market dynamics are poised to influence choices based on factors such as sustainability goals , manufacturing efficiency , and overall scope considerations .”
Davis introduces a critical aspect of immersion cooling — resiliency concerns , especially in the context of topological resiliency and concurrent maintainability . She differentiates between single-phase and two-phase immersion systems , emphasising their distinct characteristics :
• Single-phase systems , with their ability to keep the fluid in a liquid state , provide advantages in terms of pump redundancy and maintainability
• Two-phase systems , where the coolant boils for cooling , offer efficiency benefits but pose challenges when it comes to servicing servers without disrupting the entire tank
She highlights the shift in thinking about resiliency that comes with adopting immersion cooling . “ The need for routine maintenance and incident response planning necessitates a different approach , impacting how teams handle server maintenance , tank seal breaks and workload adjustments .”
There are implications with immersion cooling in hybrid environments , where liquid cooling needs to be integrated with air cooling . Davis notes that immersion cooling forces a different scale of integration , requiring a commitment to replacing a whole rack with a tank . This contrasts with cold plate servers that can be slotted into standard racks , offering flexibility in deployment and scalability .
Diaz emphasises the operational challenges that need to be addressed in designing liquid cooling systems . She notes that considerations go beyond the realm of building systems , involving factors such as maintaining hot aisle-cold aisle configurations . The diversity of facility water temperatures becomes a critical aspect , requiring careful planning when dealing with mixed load scenarios .
MOVING AWAY FROM OUTDOOR AIR COOLING The panellists discuss the trend of data centres moving away from utilising outdoor air for cooling . Diaz notes the dilemma faced by operators when deciding whether to incorporate outdoor air-cooling elements in new buildings . “ The balance between capital expenditure and the limited utilisation of outdoor air cooling over a short period influences this decision . Many operators are opting to forego free cooling to align with the expected rise in liquid cooling adoption in the coming years .”
Operators need to ensure the safety and resilience of the facility . Concurrent maintainability plays a critical role in ensuring that routine maintenance or incidents do not disrupt the entire workload .
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The opportunities presented by higher facility water temperatures , providing a chance to give back to local communities .
The importance of ride-through time in air-cooled data centres requires a significant reservoir of coolant provided by air . However , this dynamic changes with liquid cooling methods , particularly those utilising small volumes of fluid .
Diaz suggests that liquid cooling methods , especially cold plates , may impact traditional approaches to ride-through time during power outages . The smaller volume of fluid in liquid cooling systems poses challenges , and operators may need to consider running coolant pumps on uninterruptible power supply ( UPS ) to ensure continuous operation .
The discussion extends to hybrid designs , where the integration of liquid and air cooling is essential . There is anticipation of significant developments in fuel cell technology , with potential advancements in hydrogen fuel cells . Diaz says the ongoing research and development in fuel cell technology will have a potential impact on data centre design and deployment . The mention of hydrogen fuel cells raises the question of how power costs and regional differences , particularly in Europe and the US , will influence the adoption of such technologies .
The participants express concerns about the industry ' s potential reluctance to embrace change due to risk aversion , emphasising the need to overcome this inertia to drive progress . The fear concerns the possibility of delaying crucial advancements , leading to power constraints and operational shutdowns in the face of increasing demands .
The participants expressed optimism about the potential for fully liquid-cooled data centres by 2024 . Embracing liquid cooling technologies could bring about significant benefits , such as improved power efficiency , water re-use , higher density , and overall reduced total cost of ownership ( TCO ). There is a call to take measured risks and leverage the advantages of liquid cooling to propel the industry forward .
The concern is that a significant failure in operating a liquidcooled system might lead to a negative industry-wide perception and hinder progress .
A key potential game-changer is heat re-use , not only in terms of sustainability but also as a means to engage with and contribute to local communities . The participants express their hopes for a future where data centres can operate without traditional mechanical cooling systems , relying on dry coolers and contributing to broader environmental and community goals . The hope is that the industry will continue to innovate , and the positive aspects will outweigh the fears and challenges ahead . RACA
www . refrigerationandaircon . co . za RACA Journal I February 2025 19