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Assessment of Low Global Warming Potential Refrigerants for Waste Heat Recovery in Data Center with On-Chip Two-Phase Cooling Loop
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作者 Yuming Zhao Jing Wang +3 位作者 Bin Sun Zhenshang Wang Huashan Li jiongcong chen 《Frontiers in Heat and Mass Transfer》 EI 2024年第4期1171-1188,共18页
Data centers(DCs)are highly energy-intensive facilities,where about 30%–50%of the power consumed is attributable to the cooling of information technology equipment.This makes liquid cooling,especially in twophase mod... Data centers(DCs)are highly energy-intensive facilities,where about 30%–50%of the power consumed is attributable to the cooling of information technology equipment.This makes liquid cooling,especially in twophase mode,as an alternative to air cooling for the microprocessors in servers of interest.The need to meet the increased power density of server racks in high-performance DCs,along with the push towards lower global warming potential(GWP)refrigerants due to environmental concerns,has motivated research on the selection of two-phase heat transfer fluids for cooling servers while simultaneously recovering waste heat.With this regard,a heat pump-assisted absorption chiller(HPAAC)system for recovering waste heat in DCs with an on-chip twophase cooling loop driven by the compressor is proposed in the present paper and the low GWP hydrofluoroolefin refrigerants,including R1224yd(Z),R1233zd(E),R1234yf,R1234ze(E),R1234ze(Z),R1243zf and R1336mzz(Z),are evaluated and compared against R245fa as server coolant.For theHPAAC system,beginning with the development of energy and economic models,the performance is analyzed through both a parametric study and optimization using the coefficient of performance(COP),energy saving ratio(ESR),payback period(PBP)and net present value(NPV)as thermo-economic indicators.Using a standard vapor compression cooling system as a benchmark,the results indicate that with the evaporation temperature between 50℃and 70℃and the subcooling degree ranging from5℃to 15°C,R1233zd(E)with moderate compressor suction pressure and pressure ratio is the best refrigerant for the HPAAC systemwhile R1234yf performs the worst.More importantly,R1233zd(E)is also superior to R245fa based on thermo-economic performance,especially under work conditions with relatively lower evaporation temperature as well as subcooling degree.Under the given working conditions,the overall COP,ESR,NPV,and PBP of R1233zd(E)HPAAC with optimum subcooling degree range from4.99 to 11.27,25.53 to 64.59,1.13 to 4.10×10^(7) CNY and 5.77 to 2.22 years,respectively.Besides,the thermo-economic performance of R1233zd(E)HPAAC under optimum working conditions in terms of subcooling degree varying with the evaporation temperature is also investigated. 展开更多
关键词 Heat pump absorption chiller waste heat recovery two-phase cooling loop
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Modeling of IEEE1588 on OPNET and Analysis of Asymmetric Synchronizing Error in Smart Substation
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作者 jiongcong chen Haizhu Wang +2 位作者 Chunchao Hu Kai Ma Zexiang Cai 《Energy and Power Engineering》 2013年第4期540-545,共6页
The IEEE1588 network time synchronization, matched with smart substation information network transmission, is becoming the next generation advanced data synchronization of the smart substation. It is known that the in... The IEEE1588 network time synchronization, matched with smart substation information network transmission, is becoming the next generation advanced data synchronization of the smart substation. It is known that the inherent asymmetry error of the network synchronization approach in the smart substation is highlighted, which is concerned particularly. This paper models the synchronization process of the IEEE1588 based on the communication simulation software of OPNET Modeler. Firstly, it builds the models of master-slave clock, IEEE1588 protocol and network synchroniza- tion model, and analyzes the composition and influencing factors of the asymmetry error. Secondly, it quantitatively analyzes the influence of the synchronous asymmetric error of the IEEE1588 affected by the network status differences and the clock synchronization signal transmission path differences. Then its correction method is analyzed, in order to improve the IEEE1588 synchronization reliability and gives the solutions to its application in smart substation. 展开更多
关键词 Smart SUBSTATION IEEE1588 Synchronization ASYMMETRIC ERROR
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Thermo-Economic Performance of Geothermal Driven High-Temperature Flash Tank Vapor Injection Heat Pump System:A Comparison Study
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作者 Huashan Li Xiaoshuang Zhao +2 位作者 Sihao Huang Lingbao Wang jiongcong chen 《Energy Engineering》 EI 2023年第8期1817-1835,共19页
Process heating constitutes a significant share of final energy consumption in the industrial sector around the world.In this paper,a high-temperature heat pump(HTHP)using flash tank vapor injection technology(FTVI)is... Process heating constitutes a significant share of final energy consumption in the industrial sector around the world.In this paper,a high-temperature heat pump(HTHP)using flash tank vapor injection technology(FTVI)is proposed to develop low-temperature geothermal source for industrial process heating with temperature above 100°C.With heat sink output temperatures between 120°C and 150°C,the thermo-economic performance of the FTVI HTHP system using R1234ze(Z)as refrigerant is analyzed and also compared to the single-stage vapor compression(SSVC)system by employing the developed mathematical model.The coefficient of performance(COP),exergy efficiency(ηexe),net present value(NPV)and payback period(PBP)are used as performance indicators.The results show that under the typical working conditions,the COP andηexe of FTVI HTHP system are 3.00 and 59.66%,respectively,and the corresponding NPV and PBP reach 8.13×106 CNY and 4.13 years,respectively.Under the high-temperature heating conditions,the thermo-economic performance of the FTVI HTHP system is significantly better than that of the SSVC system,and the larger the temperature lift,the greater the thermo-economic advantage of the FTVI HTHP system.Additionally,the FTVI HTHP system is more capable than the SSVC system in absorbing the financial risks associated with changes of electricity price and natural gas price. 展开更多
关键词 Geothermal water high-temperature heat pump flash tank vapor injection thermo-economic performance
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Economics of energy storage technology in active distribution networks 被引量:9
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作者 jiongcong chen Xudong SONG 《Journal of Modern Power Systems and Clean Energy》 SCIE EI 2015年第4期583-588,共6页
An economic and environmental evaluation of active distribution networks containing lithium ion batteries(Li-ion),sodium sulfur batteries(NaS)and vanadium redox flow batteries(VRB)was carried out using the EnergyPLAN ... An economic and environmental evaluation of active distribution networks containing lithium ion batteries(Li-ion),sodium sulfur batteries(NaS)and vanadium redox flow batteries(VRB)was carried out using the EnergyPLAN software.The prioritization schemes of the combination of energy storage systems and intermittent energy systems were studied technically and economically based on some specific situations of the grid integrated with wind power.The results suggest that the technical and economic optimal intermittent energy-storage capacity ratio was 2:1 in predetermined energy system scenarios.Liion batteries storage system performed the best in critical excess electricity production(CEEP)absorption,energy saving and emission reduction while NaS batteries storage system was the most competitive among the three due to its cheaper costs. 展开更多
关键词 Active distribution networks Intermittent power sources Battery energy storage ECONOMY OPTIMIZATION
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Impact analysis of false data injection attacks on power system static security assessment 被引量:4
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作者 jiongcong chen Gaoqi LIANG +4 位作者 Zexiang CAI Chunchao HU Yan XU Fengji LUO Junhua ZHAO 《Journal of Modern Power Systems and Clean Energy》 SCIE EI 2016年第3期496-505,共10页
Static security assessment(SSA) is an important procedure to ensure the static security of the power system.Researches recently show that cyber-attacks might be a critical hazard to the secure and economic operations ... Static security assessment(SSA) is an important procedure to ensure the static security of the power system.Researches recently show that cyber-attacks might be a critical hazard to the secure and economic operations of the power system. In this paper, the influences of false data injection attack(FDIA) on the power system SSA are studied. FDIA is a major kind of cyber-attacks that can inject malicious data into meters, cause false state estimation results, and evade being detected by bad data detection. It is firstly shown that the SSA results could be manipulated by launching a successful FDIA, which can lead to incorrect or unnecessary corrective actions. Then,two kinds of targeted scenarios are proposed, i.e., fake secure signal attack and fake insecure signal attack. The former attack will deceive the system operator to believe that the system operates in a secure condition when it is actually not. The latter attack will deceive the system operator to make corrective actions, such as generator rescheduling, load shedding, etc. when it is unnecessary and costly. The implementation of the proposed analysis is validated with the IEEE-39 benchmark system. 展开更多
关键词 Cyber physical power system Static security assessment False data injection attacks State estimation
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Cluster voltage control method for “Whole County” distributed photovoltaics based on improved differential evolution algorithm
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作者 Jing ZHANG Tonghe WANG +2 位作者 jiongcong chen Zhuoying LIAO Jie SHU 《Frontiers in Energy》 SCIE EI CSCD 2023年第6期782-795,共14页
China is vigorously promoting the “whole county promotion” of distributed photovoltaics (DPVs). However, the high penetration rate of DPVs has brought problems such as voltage violation and power quality degradation... China is vigorously promoting the “whole county promotion” of distributed photovoltaics (DPVs). However, the high penetration rate of DPVs has brought problems such as voltage violation and power quality degradation to the distribution network, seriously affecting the safety and reliability of the power system. The traditional centralized control method of the distribution network has the problem of low efficiency, which is not practical enough in engineering practice. To address the problems, this paper proposes a cluster voltage control method for distributed photovoltaic grid-connected distribution network. First, it partitions the distribution network into clusters, and different clusters exchange terminal voltage information through a “virtual slack bus.” Then, in each cluster, based on the control strategy of “reactive power compensation first, active power curtailment later,” it employs an improved differential evolution (IDE) algorithm based on Cauchy disturbance to control the voltage. Simulation results in two different distribution systems show that the proposed method not only greatly improves the operational efficiency of the algorithm but also effectively controls the voltage of the distribution network, and maximizes the consumption capacity of DPVs based on qualified voltage. 展开更多
关键词 distributed photovoltaics(DPVs) cluster partitioning improved differential evolution algorithm voltage control consumption capacity of distributed photovoltaics
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