Browsing by Author "Zhou, Xuetao"

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    Design and Thermal Environment Analysis of a Decentralized Cooling System with Surface-Mount Heat Pipe Exchangers on Servers in Data Centers
    (MDPI AG, 2022-07-14) Yuan, Xiaolei; Zhou, Xuetao; Liang, Yumin; Pan, Yiqun; Kosonen, Risto; Lin, Zhongping; Department of Mechanical Engineering; Energy efficiency and systems; Tongji University
    This paper proposes a decentralized cooling system combined with a traditional computer room air conditioning unit and server-level heat pipe exchangers for thermal environment optimization in a data center. Two cooling strategies, with heat exchangers installed above and below the servers respectively, are proposed and compared with the original CRACs system in terms of thermal environment. The simulation results of the original data center model are in good agreement with the on-site measurement results, and thus its reliability can be validated. The results show that a decentralized cooling system can effectively improve the thermal environment in data centers. To obtain the highest cooling efficiency, altogether 18 cases, where heat pipe exchangers were installed at different locations and heights, are analyzed and compared. The results show that the thermal environment is optimal when heat pipe exchangers are installed 0.01 m below each server. The local hotspot temperature is reduced by 6.8 °C, and the temperature distribution of the rack is the most uniform, which can effectively reduce the heat accumulation in data centers.
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    Phase change cooling in data centers: A review
    (Elsevier Science, 2021-04-01) Yuan, Xiaolei; Zhou, Xuetao; Pan, Yiqun; Kosonen, Risto; Cai, Hao; Gao, Yang; Wang, Yu; Department of Mechanical Engineering; Energy efficiency and systems; Nanjing Tech University; Tongji University; Nanjing Yangtze River Urban Architectural Design Co.
    With the advent of big data era, data centers (DCs) related energy use accounts for approximately 3% of the global electric power consumption. As the augmentation of data-processing performance and thermal density in DCs, its energy use will undoubtedly continuously burst. Meanwhile, the potential safety hazards, caused by IT equipment local overheating, threaten the safe operation and restrict the further development of DCs. Thus, efficient cooling approaches should be applied in DCs to ensure its safe operation and optimize its thermal environment and cooling efficiency. Phase change cooling (PCC) technology is regarded as one of the effective and widely-used cooling methods, which have been applied in DCs for several years. In this paper, the up-to-date PCC technologies are reviewed and summarized, as well as the latest progress in DC cooling field. Four main PCC technologies are discussed in this paper, namely independent heat pipe cooling, integrated heat pipe cooling, two-phase immersion cooling, and cold storage systems. Finally, the shortcomings of the current researches on the PCC methods are summarized, while some suggestions for future researches are provided to promote the application of PCC technologies and achieve safe operations and energy savings in data centers.