Literature Review on Working Fluids for Liquid Cooling Systems in Data Centers

This study reviews recent research on the working fluids used in liquid cooling systems for data centers. A total of 151 papers published between 2021 and 2025 and available in ScienceDirect were analyzed. The reviewed working fluids were classified by cooling method into immersion cooling and cold-plate-based direct liquid cooling. Each cooling method was further divided into Single-Phase and Two-Phase systems, and 34 working fluids were compared in terms of their thermophysical properties and environmental impacts. The results indicate that the criteria for selecting working fluids vary depending on the cooling configuration, phase-change behavior, thermal performance, flow characteristics, safety requirements, and global warming potential (GWP). This review provides fundamental data to support working fluid selection and the establishment of design guidelines for liquid cooling systems in high-power-density data centers.