⎪ Heating, cooling, ventilation and air conditioning ⎪
Liquid cooling in African data centres Data centre capacity to power AI processes must increase rapidly by expanding and upgrading existing facilities or building new data centres. Leon Kleyn, WSP’s technical director, mechanical in Africa, and Floris van der Walt, senior mechanical engineer, highlight the strategic opportunity that liquid cooling offers for Africa’s growing digital ecosystem.
T he African data centre market is growing quickly. Research esti- mates the current market value at US$1.94 billion in 2025 and ex - pects it to reach $3.85 billion by 2030. This rapidly increasing demand raises technical challenges in data centre cooling systems. And at the centre of the evolution is liquid cooling, a technology long understood but only now gaining traction in large-scale data centre environments. The sudden relevance of liquid cool- ing is a direct result of the explosion of AI workloads. Traditional computing relied on CPUs that processed tasks sequentially. AI, however, depends on GPUs that process multiple tasks in parallel, which significantly increases energy use and, in turn, heat generation. “In terms of performance, we are reach- ing the limit of what traditional air-cooling systems are capable of,” explains Van der Walt. “Liquid has three to four times the cooling capacity of air, so it becomes the next viable option.” Liquid cooling itself is not new, but the industry has historically not used it due to high costs, perceived risks and complexity. Now, rising heat loads have pushed technol- ogy providers and data centre operators towards solutions that can safely and ef- ficiently handle greater thermal heat rejec- tion requirements. Managing risks and technical complexity The biggest concern is leakage, which can cause liquid to come into contact with expensive electronic equipment. “Leaks are one of the biggest risks,” says Van der Walt. “You need strategies to detect and mitigate them.” Another challenge lies in maintaining the quality of the cooling fluid. GPUs use extremely fine cold-plate channels – down to microscopic dimensions – which are highly sensitive to contaminants. Minerals or impurities in potable water can block these channels, rendering the water unsuit- able for ordinary use. Kleyn notes: “Liquid cooling systems typically use demineralised water, not just standard filtered water.” Beyond demineralisation, engineers must also prevent scaling and biological growth. This is achieved by introducing a propylene glycol mixture that stabilises the
AI depends on GPUs that process multiple tasks in parallel, which significantly increases energy use and heat generation.
fluid and inhibits biofilm formation. As Van der Walt puts it, fluid treatment forms “a whole new industry on its own,” requiring collaboration between water-treatment specialists, cooling-system manufacturers and engineers. Liquid cooling offers clear efficiency advantages. “It is more efficient than nor- mal cooling,” says Kleyn, noting that an engineered liquid can reject heat far more effectively than air, lowering energy use. In water-scarce regions like South Africa, the question of water consumption and efficiency is unavoidable. “Liquid cooling does not mean significant water use,” Kleyn clarifies. “The cooling system has a closed loop, filled once at commissioning and not needing additional water during normal operation. There shouldn’t be any water consumption,” Van der Walt points out. Africa’s climate, with high ambient temperatures across many regions, does not limit the use of liquid cooling. These systems are more than capable of perform- ing optimally across a variety of ambient temperatures. Instead, the challenges facing liquid cooling adoption on the continent lie in manufacturing capacity, supply chains and specialised skills. Because Africa does not manufacture coolant distribution units (CDUs), opera - tors are dependent on global supply queues. This can lead to project delays as larger international projects take precedence in supply chains. In addition, Van der Walt notes that liquid-cooled systems are less forgiving than air-cooled ones. “Performance de- viations must be detected and corrected
immediately, and this requires specialised skills,” he explains. “This creates signifi- cant opportunities for upskilling Africa’s young workforce. But technical develop- ment for operations and maintenance staff is critical to ensure these systems operate optimally.” Where liquid cooling fits Liquid cooling is implemented only where needed. “Operators will try to use air cooling as much as possible,” says Kleyn. “Largely because of the cost and complexity of technical requirements. Demand for liquid cooling is driven by the adoption of GPU-based systems, particularly by AI-focused operators and global service providers expanding into African regions.” When an operator is ready to shift to GPU-based systems, Kleyn and Van der Walt confirm that liquid cooling can be implemented in both new and exist- ing facilities. New builds are easier, but conversions are feasible. Industrial-type buildings with generous volumes and structural flexibility could also offer the adoption of liquid-cooled designs if there is sufficient power at the site. As AI adoption accelerates across the continent, liquid cooling will increas- ingly shape the next generation of data centres in Africa. While the technology introduces new layers of complexity, it also offers significant efficiency gains and positions operators to meet the ris- ing demands of a digital, interconnected and latency-sensitive marketplace. https://www.wsp.com/
January-February 2025 • MechChem Africa ¦ 33
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