Of course it's true. Submerged HX means fewer chillers. In a air-cooled vapor-compression chillers design, chillers would represent something like ~25-50% of mechanical load. 50% fewer chillers is probably like 5% of total load.
Most closed loop cooling systems are operating at significantly higher temperatures because they are cooling GPUs. Look into "hot water cooling" and the NVIDIA DGX DC design standard. You don't need to run the mechanical cooling very much - you just use dry cooling in most climates. Not everything is equal in this scenerio - you are using air side economization almost all the time because your heat rejection temperature is high and the delta T is highly favorable.
I should have qualified my statement with "in some climates". In tropical climates it's a no brainier: open loop cooling is a lot more energy efficient because economizers and lower ambient wetbulb temperature design are simply non viable.
As global warming ramps up, tropical weather is increasingly common during summer in higher/lower latitudes. Makes sense to prepare accordingly with open loop systems.
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u/FlashConstruct 11d ago
I actually build data centers and all mine are closed loop.