Liquid-to-air eases DLC rollout, but mind the setpoints

In its idealized form, a direct liquid cooling (DLC) system enables compressor-free heat rejection by operating at high temperatures. Such a system removes heat from IT electronics using a comparatively hot coolant, then dissipates the heat through a warm facility water system and dry coolers. This approach can offer a substantial reduction in capital costs and energy use, as well as the ability to support more IT capacity in the same site power envelope.

In reality, however, few facilities are designed and optimized for DLC systems, and such implementations remain the exception. There are various reasons for this. The biggest of which is the need to support air-cooled IT loads using the same heat transport and rejection infrastructure. There is also a common preference to extract maximum performance from expensive compute silicon — while also lowering failure rates, a major availability concern for operators of large compute clusters. Both dictate lower temperatures.