EDITOR ’ S QUESTION
AI applications could support up to US $ 136 billion worth of economic benefits for just four sub-Saharan countries , Ghana , Kenya , Nigeria and South Africa by 2030 . It is also beginning to fundamentally change data centre infrastructure , driving significant changes in how high-performance computing , HPC is powered and cooled .
To put this into perspective , consider the fact that a typical IT rack used to run workloads from five to 10 kilowatts , kW , and racks running loads higher than 20 kW were considered as high-density . AI-chips , however , can require around five times as much power and five times as much cooling capacity in the same space as a traditional server . We are seeing rack densities of 40 kW per rack , and even more than 100 kW in some instances .
This means that , due to traditional cooling methods not being able to handle the heat generated by GPUs running AI calculations , the introduction of liquidcooling technologies into the data centre white space , and eventually the enterprise server room , will be a requirement for most deployments .
Getting enough power to each rack requires upgrades from the grid to the rack . In the white space specifically , this likely means high amperage busway and high-density rack PDUs . To reject the massive amount of heat generated by hardware running
AI workloads , two liquid cooling technologies are emerging as primary options .
Cold plates sit atop the heat-generating components , usually chips such as CPUs and GPUs to draw off heat . Pumped single-phase or two-phase fluid draws off heat from the cold plates to send it out of the data centre , exchanging heat but not fluids with the chip . This can remove between 70 to 75 percent of the heat generated by equipment in the rack , leaving 25 to 30 percent to be removed by air-cooling systems .
Passive or active heat exchangers replace the rear door of the IT rack with heat exchanging coils , through which fluid absorbs heat produced in the rack . These systems are often combined with other cooling systems as either a strategy to maintain room neutrality , or as part of a transitional design starting the journey into liquid cooling .
While direct-to-chip liquid cooling offers significantly higher density cooling capacity than air , it is important to note that there is still excess heat that the cold plates cannot capture . This heat will be rejected into the data room unless it is contained and removed through other means such as rear-door heat exchangers or room air cooling . p
WOJTEK PIORKO , MANAGING DIRECTOR FOR AFRICA , VERTIV
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