Performance Comparison of Five Data Center Server Thermal Management Technologies

Industry power trends are leading IT decision makers and data center operations groups to consider alternatives to traditional air cooling. Just a couple years ago the server CPU and GPU power levels were only 205 W and 300 W, respectively. Today, performance competition among CPU vendors is pushing CPU power towards 500 W per socket. AI/ML workloads have pushed GPU power to 700 W with 1000 W likely just around the corner. At the same time, the global energy crisis is pushing all sectors to be more sustainable. With servers and data centers this sustainability push means operators are targeting green energy sources, overall reductions in facility energy use, and to reduce or even eliminate water use. These industry challenges require new cooling solutions to both enable sufficient cooling at power levels beyond the capability of air cooling and to yield solutions that offer realizable sustainability opportunities. Five unique cooling solutions exist in the market today; each have varying cooling performance, cost, and reliance on facility chilled water supplies. These technologies include air cooling using larger server chassis form factors, direct liquid cooling (DLC) using water or Propylene Glycol (PG) solutions, DLC using 2-phase dielectric fluids, single phase immersion, and 2-phase immersion. The purpose of this paper is to provide a directional comparison of thermal performance at equivalent operating conditions using simplified thermal models of each of these technologies.