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A Review of energy efficiency.in Data Processing Centers

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Journal of energy and Power Engineering 2011年第4期5卷 361-372页

作者： C. Redondo A. Fern/mdez Castile and Leon Technological Center for Supercomputing （FCSC） Edificio CRAI- TIC Campus de Vegazana s/n University of Le6n E-24071-Lean Spain Electrical Engineering and Systems Engineering and Automatic Control Department Faculty of lndustrial and Computer Engineering University of Leon E-24071-Leon Spain

This article explores, through a case study, measures of energy efficiency.in data processing centers. An analysis of this case demonstrates how the design criteria could improve the rate of consumption in IT centers, which is currently the second most contaminating industry on the planet, and is the responsible for 2% of CO2 emissions, surpassed only by the aeronautical industry. The present and future situation of IT center energy consumption and associated environmental effects is analyzed, and also looks at how state-of-the-art technology, correctly implemented, could ensure significant rationalization of data processing center energy consumption. The article will examine optimization techniques, specific problems and case studies.

关键词： energy management data processing centers energy efficiency.

The Study of Thermal Mass as a Passive Design Technique for Building Comfort and energy efficiency

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Journal of Civil Engineering and Architecture 2011年第1期5卷 84-88页

作者： Mohammad Arif Kamal Department of Architecture King Fahd University of Petroleum ＆ Minerals Saudi Arabia

The day/night （diurnal） changes in temperature and solar radiation pose challenges for maintaining human thermal comfort in buildings. Passive and energy-conserving buildings seek to manage the available thermal energy by lowering peaks and dampening the fluctuations in order to maintain conditions for human comfort. Appropriate use of thermal mass moderates the internal temperatures by averaging diurnal extremes. Thermal mass is one of the powerful tools which architects and designers can use to control temperature. It can be used to optimize the performance of energy-conserving buildings that rely primarily on mechanical heating and cooling strategies. Massive building envelopes-such as masonry, concrete, earth, and insulating concrete forms （ICFs） can be utilized as one of the simplest ways of reducing building heating and cooling loads. This article analyses the role and effectiveness of thermal mass as a strategy for providing indoor thermal comfort for passive solar and energy conserving buildings.

关键词： Thermal mass passive solar building comfort energy efficiency.

Clustering routing algorithm of wireless sensor networks based on Bayesian game

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Journal of Systems Engineering and Electronics 2012年第1期23卷 154-159页

作者： Gengzhong Zheng Sanyang Liu Xiaogang Qi School of Computer Science and Technology Xidian University Xi＇an 710071 R R. China Department of Mathematics and Information Technology Hanshan Normal University Chaozhou 521041 R R. China School of Science Xidian University Xi＇an 710071 R R. China

To avoid uneven energy consuming in wireless sen- sor networks, a clustering routing model is proposed based on a Bayesian game. In the model, Harsanyi transformation is introduced to convert a static game of incomplete information to the static game of complete but imperfect information. In addition, the existence of Bayesian nash equilibrium is proved. A clustering routing algorithm is also designed according to the proposed model, both cluster head distribution and residual energy are considered in the design of the algorithm. Simulation results show that the algorithm can balance network load, save energy and prolong network lifetime effectively.

关键词： wireless sensor networks (WSNs) clustering routing Bayesian game energy efficiency.

Performance evaluation of multiple relays cooperative GBn-ARQ with limited retransmission

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Journal of Systems Engineering and Electronics 2015年第6期26卷 1210-1215页

作者： Suoping Li Yongqiang Zhou Xijuan Yang Zufang Dou School of Science Lanzhou University of Technology School of Electrical & Information Engineering Lanzhou University of Technology

We investigate the performance of multiple relays cooperative go back n automatic repeat request （MRC-GBn-ARQ） protocol with limited retransmission. An N＋2-state Markov transition model is constructed for analyzing arbitrary packet transmission process with limited retransmission. Then the system＇s steadystate distribution is derived by using the Kolmogorov equations. Further, the mean packet transmission delay and startup delay are obtained respectively; the channel utilization is derived based on discrete-time Geom/G/1 queue model with startup. Also, we get the energy efficiency.of the MRC-GBn-ARQ based on energy analytical model. Especially, the presented models are contrary to the classical ARQ protocols of always allowing infinite retransmis- sion, and our analysis of the MRC-GBn-ARQ protocol with limited retransmission provides theoretical results for reducing the system＇s delay and energy consumption. Finally, analysis is validated through some numerical simulations.

关键词： steady-state distribution mean packet transmissiondelay channel utilization energy efficiency.

energy-efficient adaptive sensor scheduling for target tracking in wireless sensor networks

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控制理论与应用（英文版） 2010年第1期8卷 86-92页

作者： Wendong XIAO Sen ZHANG Jianyong LIN Chen Khong THAM Institute for lnfocomm Research 1 Fusionopolis Way #21-01 Connexis Singapore 138632 School of Mechanical and Aeronautical Engineering Singapore Polytechnic 500 Dover Road Singapore 139651 School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798

Sensor scheduling is essential to collaborative target tracking in wireless sensor networks （WSNs）. In the existing works for target tracking in WSNs, such as the information-driven sensor query （IDSQ）, the tasking sensors are scheduled to maximize the information gain while minimizing the resource cost based on the uniform sampling intervals, ignoring the changing of the target dynamics and the specific desirable tracking goals. This paper proposes a novel energy-efficient adaptive sensor scheduling approach that jointly selects tasking sensors and determines their associated sampling intervals according to the predicted tracking accuracy and tracking energy cost. At each time step, the sensors are scheduled in alternative tracking mode, namely, the fast tracking mode with smallest sampling interval or the tracking maintenance mode with larger sampling interval, according to a specified tracking error threshold. The approach employs an extended Kalman filter （EKF）-based estimation technique to predict the tracking accuracy and adopts an energy consumption model to predict the energy cost. Simulation results demonstrate that, compared to a non-adaptive sensor scheduling approach, the proposed approach can save energy cost significantly without degrading the tracking accuracy.

关键词： Wireless sensor network Target tracking Sensor scheduling Extended Kalman filter energy efficiency.

Characteristics of the Water Steam Turbocompressors Applied in the Concentrator Systems

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Journal of Chemistry and Chemical Engineering 2012年第1期6卷 18-26页

作者： Milan Nikola Sarevski Vasko Nikola Sarevski Faculty of Mechanical Engineering University ＂Sv. Kiril i Metodij＂ Skopje MK-1000 R. Macedonia

The main geometrical and operating parameters of the water steam centrifugal compressors working in various concentrator operating conditions are realized in this paper. The interdependence between centrifugal stage pressure ratio, peripheral Mach number and impeller peripheral speed, as well the influence of the concentrator system capacity on the dimensions of the centrifugal compressor are determined to obtain the range of reasonable usage of the centrifugal thermocompression systems in the industrial concentrators. The high peripheral impeller speed, high Mach number and high pressure ratio cause separated jet-wake flow and transonic flow phenomena in the water steam centrifugal compressor flow field. The calculating methods for 3-D viscid unsteady transonic fluid flows in the turbocompressors are discussed and the results of CFD simulations and experimental investigations are used for optimal design of the water steam centrifugal compressor flow field. The application of the centrifugal compressor in the industrial concentrators with thermocompression systems and the influence on the energy efficiency.of the systems are analyzed. Significant increment of the energy efficiency.of the industrial concentrators can be achieved by introduction of the thermocompression systems.

关键词： Water turbocompressor concentrator energy efficiency.

The First Natural Ventilation Assessment in Building Design in Djibouti

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Journal of Life Sciences 2016年第6期10卷 298-306页

作者： Abdou Idris Omar Abdoulkader Ibrahim Idriss Omar Assowe Dabar Abdourazack Ahmed Kayad Mohamed Said Darar Research Center at the University of Djibouti (CR UD/GRE) Faculty of Engineers Street Djanaleh B.P. 1904 Djibouti Institute for Earth Sciences Centre d'Etudes et de Recherche de Djibouti (CERD) Airportstreet B.P. 486 Djibouti

With a sustained period of economic growth, rapidly growing populations and with more diversified economies Africa need sustainable development; hence the greater need for massive investments in energy. Sub-Saharan countries such as Djibouti have the potential and ability to harness their natural ventilation as a passive cooling system for designing new houses. The rapid expansion of the Djibouti city is affecting negatively the environment and the safety and comfort of its inhabitants. Proper atmospheric urban planning and management are key to making cities environmentally friendly and sustainable. Based on energy consumption, climate conditions in Djibouti and numerical analysis using Computational Fluid Dynamics （CFD）, it is apparent that the natural ventilation creates a thermally comfortable indoor environment in buildings during the cool season of the year. Measured wind data from two measurement systems are presented and discussed. Statistical analyses, wind rose, Weibull distribution were carried out to understand the natural ventilation characteristic, which is used for evolving the basic criteria for economic viability of building in the semi-arid climate of Djibouti. The study found that it is possible to benefit from natural ventilation in buildings during the cool season of the year.

关键词： Computational Fluid Dynamics airflow simulation natural ventilation bioclimatic design weather data energy efficiency.

Analysis of Thermal Bridge Impact in a Hotel Building for the Eight Brazilian Bioclimatic Zones

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Journal of Civil Engineering and Architecture 2015年第4期9卷 393-400页

作者： Eduardo Grala da Cunha Beatriz Echenique Gioielli DTC (Department of Construction Technology) Architecture Faculty Federal University of Pelotas Pelotas 96020-240 Brazil

This article aims to present an analysis of the influence of thermal bridges on reinforced concrete structural systems regarding energy performance of the envelope of a commercial building located in the bioclimatic zones 1 to 8 in Brazil, using computer simulation. The method used to achieve this goal includes the following steps：（1） definition and configuration of the base case; （2） definition and configuration of the reference model; （3） optimization of energy modeling; （4） energy modeling and comparison of consumption between the base case and the reference model. Main results showed that thermal bridges in reinforced concrete interfere on the building＇s energy performance and that the impact is related to the WWR （window-to-wall ratio） on the building. For hotel buildings with WWR from 30% to 45%, thermal bridges imply a decrease in estimated consumption, which can reach 10%, depending on the bioclimatic zone. For 60% WWR, the non-consideration of thermal bridges can represent up to 5% of increase in estimated consumption, depending on the Brazilian bioclimatic zone.

关键词： Thermal bridge thermal performance energy efficiency.

Power Quality Comparative Analysis between UPF and SAPF

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Journal of energy and Power Engineering 2021年第4期15卷 117-127页

作者： Nicolae Badea Alexandru Dusa Nicu Roman “Dunarea de Jos”University of Galati Domneasca StreetNo.47 GalatiRomania Nicu Roman-Smar Tech Automation SRL Str.Cristofor ColumbNo.14 GalatiRomania

This paper makes a technical analysis of the converter’s topologies that are conventionally employed in three-phase three-wire in increasing the power factor and harmonics eliminating,namely unit power factor(UPF)and shunt active power filter(SAPF)and highlights the improvement of energy quality in the supply *** paper highlights that the mathematical model of the three-phase PWM rectifier in the dq coordinate system is similar for both *** structure of the control schemes of the two topologies for increasing the energy quality is similar by transformation of three-phase stationary coordinate system(a,b,c),to synchronous rotating(d,q)coordinate system that synchronously rotates with the fundamental voltage of the *** analysis and simulation results show that the control in synchronous rotating coordinate system has high power factor and low THDi for the both topologies.

关键词： Power quality unit power factor shunt active power filter energy efficiency.