Liquid to Air Cooling for High Heat Density Liquid Cooled Data Centers

Abstract Growing demand for dense and high-performing IT compute capacity to support deep learning and artificial intelligence workloads necessitates data centers to look for more robust thermal management strategies. Today, data centers across the world are turning to liquid-based cooling solutions to keep up with the increased cooling demand for high power racks approaching 100kW of heat dissipation. Deploying direct-to-chip cold plate liquid cooling is one of the mainstream approaches which allows targeted cooling of high-power processors. This study provides the framework for a hybrid in row cooler (IRC) with liquid-to-air (L2A) heat exchanger (HX) system delivering chilled coolant to liquid-cooling cold plates mounted to the high heat dissipation electronics. This approach is useful for high heat density cooling of racks where no primary facility coolant is available at the data center. The present study aims to investigate the thermo-hydraulic performance of a distinct L2A IRC system that supplies cold secondary coolant (PG 25%) into the cooling loops of liquid-cooled servers in racks within an existing air-cooled data center. Thermal test vehicles (TTVs) are built to replicate actual high heat density servers. From the cold plate to data center level the proper choice of each level component was described based on their cooling performance and relevance. Three different cooling loop/rack designs are characterized experimentally, and detailed analytical and numerical (FNM) simulations are developed to analyze the heat exchanger performance. The FNM and CFD model of a data center are done in two steady and transient forms to study the performance of the L2A IRC in a data center.