Research Status and Future Development of Cooling Technologies for Green and Energy-Efficient Data Centers

Data centers are important infrastructure in China, with constantly increasing industry size, market revenues, and electricity consumption. The major cooling systems of data centers currently in operation in China are air-cooled, with a low energy utilization rate and great potentials for energy saving. Therefore, it is imperative to develop novel cooling technologies for green and energyefficient data centers. The cooling technology needs to solve two problems. First, as equipment heat production increases, the cooling capacity of the cooling system needs to be improved to match heat production and transfer rates. Second, to address the low energy efficiency problem, green and energy-efficient cooling technologies with industrial application prospects need to be developed. This study reviews the development status of data center cooling methods and categorizes cooling technologies into air conditioner cooling, fresh air cooling, indirect cooling, direct single-phase liquid cooling, and direct two-phase liquid cooling. We analyze the development trends of cooling technologies and suggest that green and high-efficient data centers should focus on the improvement in the efficiency of cooling systems, optimizations of hot and cold fluid channels, applications of new liquid cooling materials, and promotion of heat recovery systems. Furthermore, we propose suggestions for the stable and orderly development of the data center industry from the aspects of optimizing top-level design, developing key technologies, formulating scientific standards, improving industrial layout, and focusing on energy structure.