Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 1180

Search results for: high efficiency

1180 Power Electronic Solution for High Energetic Efficiency of a Thermo Plant

Authors: Aziza Benaboud, Alfred Rufer

Abstract:

In this paper the authors propose a flexible electronic solution, to improve the energetic efficiency of a thermo plant. This is achieved by replacing the mechanical gear box, placed traditionally between a gas turbine and a synchronous generator; by a power electronic converter. After reminding problematic of gear boxes and interest of a proposed electronic solution in high power plants, the authors describe a new control strategy for an indirect frequency converter, which is characterized by its high efficiency due to the use of SWM: Square Wave Modulation. The main advantage of this mode is the quasi absence of switching losses. A control method is also proposed to resolve some problems incurred by using square wave modulation, in particular to reduce the harmonics distortion of the output inverter voltage and current. Simulation examples as well as experimental results are included.

Keywords: Angle shift, high efficiency, indirect converter, gas turbine, NPC three level converter, square wave modulation SWM, switching angle.

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1179 Motion Estimator Architecture with Optimized Number of Processing Elements for High Efficiency Video Coding

Authors: Seongsoo Lee

Abstract:

Motion estimation occupies the heaviest computation in HEVC (high efficiency video coding). Many fast algorithms such as TZS (test zone search) have been proposed to reduce the computation. Still the huge computation of the motion estimation is a critical issue in the implementation of HEVC video codec. In this paper, motion estimator architecture with optimized number of PEs (processing element) is presented by exploiting early termination. It also reduces hardware size by exploiting parallel processing. The presented motion estimator architecture has 8 PEs, and it can efficiently perform TZS with very high utilization of PEs.

Keywords: Motion estimation, test zone search, high efficiency video coding, processing element, optimization.

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1178 High Efficiency Perovskite Solar Cells Fabricated under Ambient Conditions with Mesoporous TiO2/In2O3 Scaffold

Authors: A. Apostolopoulou, D. Sygkridou, A. N. Kalarakis, E. Stathatos

Abstract:

Mesoscopic perovskite solar cells (mp-PSCs) with mesoporous bilayer were fabricated under ambient conditions. The bilayer was formed by capping the mesoporous TiO2 layer with a layer of In2O3. CH3NH3I3-xClx mixed halide perovskite was prepared through the one-step method and was used as the light absorber. The mp-PSCs with the composite TiO2/In2O3 mesoporous layer exhibited optimized electrical parameters, compared with the PSCs that employed only a TiO2 mesoporous layer, with a current density of 23.86 mA/cm2, open circuit voltage of 0.863 V, fill factor of 0.6 and a power conversion efficiency of 11.2%. These results indicate that the formation of a proper semiconductor capping layer over the basic TiO2 mesoporous layer can facilitate the electron transfer, suppress the recombination and subsequently lead to higher charge collection efficiency.

Keywords: Ambient conditions, high efficiency solar cells, mesoscopic perovskite solar cells, TiO2/In2O3 bilayer.

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1177 Loss Analysis of Half Bridge DC-DC Converters in High-Current and Low-Voltage Applications

Authors: A. Faruk Bakan, İsmail Aksoy, Nihan Altintaş

Abstract:

In this paper, half bridge DC-DC converters with transformer isolation presented in the literature are analyzed for highcurrent and low-voltage applications under the same operation conditions, and compared in terms of losses and efficiency. The conventional and improved half-bridge DC-DC converters are simulated, and current and voltage waveforms are obtained for input voltage Vdc=500V, output current IO=450A, output voltage VO=38V and switching frequency fS=20kHz. IGBTs are used as power semiconductor switches. The power losses of the semiconductor devices are calculated from current and voltage waveforms. From simulation results, it is seen that the capacitor switched half bridge converter has the best efficiency value, and can be preferred at high power and high frequency applications.

Keywords: Isolated half bridge DC-DC converter, high-current low-voltage applications, soft switching, high efficiency.

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1176 High-Efficiency Comparator for Low-Power Application

Authors: M. Yousefi, N. Nasirzadeh

Abstract:

In this paper, dynamic comparator structure employing two methods for power consumption reduction with applications in low-power high-speed analog-to-digital converters have been presented. The proposed comparator has low consumption thanks to power reduction methods. They have the ability for offset adjustment. The comparator consumes 14.3 μW at 100 MHz which is equal to 11.8 fJ. The comparator has been designed and simulated in 180 nm CMOS. Layouts occupy 210 μm2.

Keywords: Comparator, low, power, efficiency.

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1175 The Effect of Cyclone Shape and Dust Collector on Gas-Solid Flow and Performance

Authors: Kyoungwoo Park, Chol-Ho Hong, Ji-Won Han, Byeong-Sam Kim, Cha-Sik Park, Oh Kyung Kwon

Abstract:

Numerical analysis of flow characteristics and separation efficiency in a high-efficiency cyclone has been performed. Several models based on the experimental observation for a design purpose were proposed. However, the model is only estimated the cyclone's performance under the limited environments; it is difficult to obtain a general model for all types of cyclones. The purpose of this study is to find out the flow characteristics and separation efficiency numerically. The Reynolds stress model (RSM) was employed instead of a standard k-ε or a k-ω model which was suitable for isotropic turbulence and it could predict the pressure drop and the Rankine vortex very well. For small particles, there were three significant components (entrance of vortex finder, cone, and dust collector) for the particle separation. In the present work, the particle re-entraining phenomenon from the dust collector to the cyclone body was observed after considerable time. This re-entrainment degraded the separation efficiency and was one of the significant factors for the separation efficiency of the cyclone.

Keywords: CFD, High-efficiency cyclone, Pressure drop, Rankine vortex, Reynolds stress model (RSM), Separation efficiency.

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1174 Mix Design Curves for High Volume Fly Ash Concrete

Authors: S. S. Awanti, Aravindakumar B. Harwalkar

Abstract:

Concrete construction in future has to be environmental friendly apart from being safe so that society at large is benefited by the huge investments made in the infrastructure projects. To achieve this, component materials of the concrete system have to be optimized with reference to sustainability. This paper presents a study on development of mix proportions of high volume fly ash concrete (HFC). A series of HFC mixtures with cement replacement levels varying between 50% and 65% were prepared with water/binder ratios of 0.3 and 0.35. Compressive strength values were obtained at different ages. From the experimental results, pozzolanic efficiency ratios and mix design curves for HFC were established.

Keywords: Age factor, compressive strength, high volume fly ash concrete, pozzolanic efficiency ratio.

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1173 Novel Approach to Design of a Class-EJ Power Amplifier Using High Power Technology

Authors: F. Rahmani, F. Razaghian, A. R. Kashaninia

Abstract:

This article proposes a new method for application in communication circuit systems that increase efficiency, PAE, output power and gain in the circuit. The proposed method is based on a combination of switching class-E and class-J and has been termed class-EJ. This method was investigated using both theory and simulation to confirm ∼72% PAE and output power of >39dBm. The combination and design of the proposed power amplifier accrues gain of over 15dB in the 2.9 to 3.5GHz frequency bandwidth. This circuit was designed using MOSFET and high power transistors. The loadand source-pull method achieved the best input and output networks using lumped elements. The proposed technique was investigated for fundamental and second harmonics having desirable amplitudes for the output signal.

Keywords: Power Amplifier (PA), GaN HEMT, Class-J and Class-E, High Efficiency.

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1172 Managers' Empowerment in High School by Knowledge Management

Authors: B. Azizi Nejad, M.M. Seiied Abbaszadeh

Abstract:

The purpose of the present study is the investigation of the relationship between knowledge management and enabling managers based on achieving proper function. This research is descriptive and investigative. The sample includes all male and female high school managers of first and second regions of Urmia including 98 school and accordingly 98 managers. The instrument applied was a questionnaire. To sum up, there is a statistically significant relationship between knowledge management and empowering managers. In the end, several suggestions are provided.

Keywords: Empowering managers, high school managers' efficiency, knowledge, knowledge management.

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1171 Comprehensive Assessment of Energy Efficiency within the Production Process

Authors: S. Kreitlein, N. Eder, A. Syed-Khaja, J. Franke

Abstract:

The importance of energy efficiency within the production processes increases steadily. For a comprehensive assessment of energy efficiency within the production process, unfortunately no tools exist or have been developed yet. Therefore the Institute for Factory Automation and Production Systems at the Friedrich-Alexander-University Erlangen-Nuremberg has developed two methods with the goal of achieving transparency and a quantitative assessment of energy efficiency namely EEV (Energy Efficiency Value) and EPE (Energetic Process Efficiency). This paper describes the basics and state-of-the-art as well as the developed approaches.

Keywords: Energy efficiency, energy efficiency value, energetic process efficiency, production.

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1170 Multi-Level Pulse Width Modulation to Boost the Power Efficiency of Switching Amplifiers for Analog Signals with Very High Crest Factor

Authors: Jan Doutreloigne

Abstract:

The main goal of this paper is to develop a switching amplifier with optimized power efficiency for analog signals with a very high crest factor such as audio or DSL signals. Theoretical calculations show that a switching amplifier architecture based on multi-level pulse width modulation outperforms all other types of linear or switching amplifiers in that respect. Simulations on a 2 W multi-level switching audio amplifier, designed in a 50 V 0.35 mm IC technology, confirm its superior performance in terms of power efficiency. A real silicon implementation of this audio amplifier design is currently underway to provide experimental validation.

Keywords: Audio amplifier, multi-level switching amplifier, power efficiency, pulse width modulation, PWM, self-oscillating amplifier.

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1169 A Super-Efficiency Model for Evaluating Efficiency in the Presence of Time Lag Effect

Authors: Yanshuang Zhang, Byungho Jeong

Abstract:

In many cases, there are some time lag between the consumption of inputs and the production of outputs. This time lag effect should be considered in evaluating the performance of organizations. Recently, a couple of DEA models were developed for considering time lag effect in efficiency evaluation of research activities. Multi-periods input(MpI) and Multi-periods output(MpO) models are integrate models to calculate simple efficiency considering time lag effect. However, these models can’t discriminate efficient DMUs because of the nature of basic DEA model in which efficiency scores are limited to ‘1’. That is, efficient DMUs can’t be discriminated because their efficiency scores are same. Thus, this paper suggests a super-efficiency model for efficiency evaluation under the consideration of time lag effect based on the MpO model. A case example using a long term research project is given to compare the suggested model with the MpO model.

Keywords: DEA, Super-efficiency, Time Lag.

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1168 Network Based High Performance Computing

Authors: Karanjeet Singh Kahlon, Gurvinder Singh, Arjan Singh

Abstract:

In the past few years there is a change in the view of high performance applications and parallel computing. Initially such applications were targeted towards dedicated parallel machines. Recently trend is changing towards building meta-applications composed of several modules that exploit heterogeneous platforms and employ hybrid forms of parallelism. The aim of this paper is to propose a model of virtual parallel computing. Virtual parallel computing system provides a flexible object oriented software framework that makes it easy for programmers to write various parallel applications.

Keywords: Applet, Efficiency, Java, LAN

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1167 3 State Current Mode of a Grid Connected PV Converter

Authors: Attila Balogh, Eszter Varga, István Varjasi

Abstract:

Nowadays in applications of renewable energy sources it is important to develop powerful and energy-saving photovoltaic converters and to keep the prescriptions of the standards. In grid connected PV converters the obvious solution to increase the efficiency is to reduce the switching losses. Our new developed control method reduces the switching losses and keeps the limitations of the harmonic distortion standards. The base idea of the method is the utilization of 3-state control causing discontinuous current mode at low input power. In the following sections the control theory, the realizations and the simulation results are presented.

Keywords: Discontinuous current, high efficiency, PVconverter, control method.

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1166 Power Efficiency Characteristics of Magnetohydrodynamic Thermodynamic Gas Cycle

Authors: Mahmoud Huleihil

Abstract:

In this study, the performance of a thermodynamic gas cycle of magnetohydrodynamic (MHD) power generation is considered and presented in terms of power efficiency curves. The dissipation mechanisms considered include: fluid friction modeled by means of the isentropic efficiency of the compressor, heat transfer leakage directly from the hot reservoir to the cold heat reservoir, and constant velocity of the MHD generator. The study demonstrates that power and efficiency vanish at the extremes of both slow and fast operating conditions. These points are demonstrated on power efficiency curves and the locus of efficiency at maximum power and the locus of maximum efficiency. Qualitatively, the considered loss mechanisms have a similar effect on the efficiency at maximum power operation and on maximum efficiency operation, thus these efficiencies are reduced, even for small values of the loss mechanisms.

Keywords: Magnetohydrodynamic generator, electrical efficiency, maximum power, maximum efficiency, heat engine.

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1165 DC Link Floating for Grid Connected PV Converters

Authors: Attila Balogh, Eszter Varga, István Varjasi

Abstract:

Nowadays there are several grid connected converter in the grid system. These grid connected converters are generally the converters of renewable energy sources, industrial four quadrant drives and other converters with DC link. These converters are connected to the grid through a three phase bridge. The standards prescribe the maximal harmonic emission which could be easily limited with high switching frequency. The increased switching losses can be reduced to the half with the utilization of the wellknown Flat-top modulation. The suggested control method is the expansion of the Flat-top modulation with which the losses could be also reduced to the half compared to the Flat-top modulation. Comparing to traditional control these requirements can be simultaneously satisfied much better with the DLF (DC Link Floating) method.

Keywords: DC link floating, high efficiency, PV converter, control method.

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1164 High Efficiency Class-F Power Amplifier Design

Authors: Abdalla Mohamed Eblabla

Abstract:

Due to the high increase in and demand for a wide assortment of applications that require low-cost, high-efficiency, and compact systems, RF power amplifiers are considered the most critical design blocks and power consuming components in wireless communication, TV transmission, radar, and RF heating. Therefore, much research has been carried out in order to improve the performance of power amplifiers. Classes-A, B, C, D, E and F are the main techniques for realizing power amplifiers.

An implementation of high efficiency class-F power amplifier with Gallium Nitride (GaN) High Electron Mobility Transistor (HEMT) was realized in this paper. The simulation and optimization of the class-F power amplifier circuit model was undertaken using Agilent’s Advanced Design system (ADS). The circuit was designed using lumped elements.

Keywords: Power Amplifier (PA), Gallium Nitride (GaN), Agilent’s Advanced Design system (ADS) and lumped elements.

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1163 High Efficiency Electrolyte Lithium Battery and RF Characterization

Authors: Wei Quan, Liu Chao, Mohammed N. Afsar

Abstract:

The dielectric properties and ionic conductivity of novel "ceramic state" polymer electrolytes for high capacity lithium battery are characterized by Radio frequency and Microwave methods in two broad frequency ranges from 50 Hz to 20 KHz and 4 GHz to 40 GHz. This innovative solid polymer electrolyte which is highly ionic conductive (10-3 S/cm at room temperature) from -40oC to +150oC can be used in any battery application. Such polymer exhibits properties more like a ceramic rather than polymer. The various applied measurement methods produced accurate dielectric results for comprehensive analysis of electrochemical properties and ion transportation mechanism of this newly invented polymer electrolyte. Two techniques and instruments employing air gap measurement by Capacitance Bridge and in-waveguide measurement by vector network analyzer are applied to measure the complex dielectric spectra. The complex dielectric spectra are used to determine the complex alternating current electrical conductivity and thus the ionic conductivity.

Keywords: Polymer electrolyte, dielectric permittivity, lithium battery, ionic relaxation, microwave measurement.

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1162 Heating of High-Density Hydrogen by High- Current Arc Radiation

Authors: A. V. Budin, Ph. G. Rutberg, M. E. Pinchuk, A. A. Bogomaz, V. Yu. Svetova

Abstract:

The investigation results of high-density hydrogen heating by high-current electric arc are presented at initial pressure from 5 MPa to 160 MPa with current amplitude up to 1.6 MA and current rate of rise 109-1011 A/s. When changing the initial pressure and current rate of rise, channel temperature varies from several electronvolts to hundreds electronvolts. Arc channel radius is several millimeters. But the radius of the discharge chamber greater than the radius of the arc channel on approximately order of magnitude. High efficiency of gas heating is caused by radiation absorption of hydrogen surrounding the arc. Current channel consist from vapor of the initiating wire. At current rate of rise of 109 A/s and relatively small current amplitude gas heating occurs due to radiation absorption in the band transparency of hydrogen by the wire vapours with photon energies less than 13.6 eV. At current rate of rise of 1011 A/s gas heating is due to hydrogen absorption of soft X-rays from discharge channel.

Keywords: High-density hydrogen heating by high-current electric arc.

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1161 High Efficiency, Selectivity against Cancer Cell Line of Purified L-Asparaginase from Pathogenic Escherichia coli

Authors: Hazim Saadoon Aljewari, Mohammed Ibraheem Nader, Abdul Hussain M. Alfaisal, NatthidaWeerapreeyakul, Sahapat

Abstract:

L-asparaginase was extracted from pathogenic Escherichia coli which was isolated from urinary tract infection patients. L-asparaginase was purified 96-fold by ultrafiltration, ion exchange and gel filtration giving 39.19% yield with final specific activity of 178.57 IU/mg. L-asparaginase showed 138,356±1,000 Dalton molecular weight with 31024±100 Dalton molecular mass. Kinetic properties of enzyme resulting 1.25×10-5 mM Km and 2.5×10-3 M/min Vmax. L-asparaginase showed a maximum activity at pH 7.5 when incubated at 37 ºC for 30 min and illustrated its full activity (100%) after 15 min incubation at 20-37 ºC, while 70% of its activity was lost when incubated at 60 ºC. L-asparaginase showed cytotoxicity to U937 cell line with IC50 0.5±0.19 IU/ml, and selectivity index (SI=7.6) about 8 time higher selectivity over the lymphocyte cells. Therefore, the local pathogenic E. coli strains may be used as a source of high yield of L-asparaginase to produce anti cancer agent with high selectivity.

Keywords: L-asparaginase, Purification, Cytotoxicity, selectivity index

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1160 Design of PI and Fuzzy Controller for High-Efficiency and Tightly Regulated Full Bridge DC-DC Converter

Authors: Sudha Bansal, Lalit Mohan Saini, Dheeraj Joshi

Abstract:

The controller is used to improve the dynamic performance of DC-DC converter by achieving a robust output voltage against load disturbances. This paper presents the performance of PI and Fuzzy controller for a phase- shifted zero-voltage switched full-bridge PWM (ZVS FB- PWM) converters with a closed loop control. The proposed converter is regulated with minimum overshoot and good stability. In this paper phase-shift control method is used as an effective tool to reduce switching losses and duty cycle losses. A 1kW/100KHz dc/dc converter is simulated and analyzed using MATLAB. The circuit is simulated for static and dynamic load (DC motor). It has been observed that performance of converter with fuzzy controller is better than that of PI controller. An efficiency comparison of the converter with a reported topology has also been carried out.

Keywords: Full-bridge converter, phase-shifted, synchronous rectifier (SR), zero-voltage switching (ZVS).

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1159 High Efficiency Solar Thermal Collectors Utilization in Process Heat: A Case Study of Textile Finishing Industry

Authors: Gökçen A. Çiftçioğlu, M. A. Neşet Kadırgan, Figen Kadırgan

Abstract:

Solar energy, since it is available every day, is seen as one of the most valuable renewable energy resources. Thus, the energy of sun should be efficiently used in various applications. The most known applications that use solar energy are heating water and spaces. High efficiency solar collectors need appropriate selective surfaces to absorb the heat. Selective surfaces (Selektif-Sera) used in this study are applied to flat collectors, which are produced by a roll to roll cost effective coating of nano nickel layers, developed in Selektif Teknoloji Co. Inc. Efficiency of flat collectors using Selektif-Sera absorbers are calculated in collaboration with Institute for Solar Technik Rapperswil, Switzerland. The main cause of high energy consumption in industry is mostly caused from low temperature level processes. There is considerable effort in research to minimize the energy use by renewable energy sources such as solar energy. A feasibility study will be presented to obtain the potential of solar thermal energy utilization in the textile industry using these solar collectors. For the feasibility calculations presented in this study, textile dyeing and finishing factory located at Kahramanmaras is selected since the geographic location was an important factor. Kahramanmaras is located in the south east part of Turkey thus has a great potential to have solar illumination much longer. It was observed that, the collector area is limited by the available area in the factory, thus a hybrid heating generating system (lignite/solar thermal) was preferred in the calculations of this study to be more realistic. During the feasibility work, the calculations took into account the preheating process, where well waters heated from 15 °C to 30-40 °C by using the hot waters in heat exchangers. Then the preheated water was heated again by high efficiency solar collectors. Economic comparison between the lignite use and solar thermal collector use was provided to determine the optimal system that can be used efficiently. The optimum design of solar thermal systems was studied depending on the optimum collector area. It was found that the solar thermal system is more economic and efficient than the merely lignite use. Return on investment time is calculated as 5.15 years.

Keywords: Solar energy, heating, solar heating.

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1158 The Layered Transition Metal Dichalcogenides as Materials for Storage Clean Energy: Ab initio Investigations

Authors: S. Meziane, H. I. Faraoun, C. Esling

Abstract:

Transition metal dichalcogenides have potential applications in power generation devices that convert waste heat into electric current by the so-called Seebeck and Hall effects thus providing an alternative energy technology to reduce the dependence on traditional fossil fuels. In this study, the thermoelectric properties of 1T and 2HTaX2 (X= S or Se) dichalcogenide superconductors have been computed using the semi-classical Boltzmann theory. Technologically, the task is to fabricate suitable materials with high efficiency. It is found that 2HTaS2 possesses the largest value of figure of merit ZT= 1.27 at 175 K. From a scientific point of view, we aim to model the underlying materials properties and in particular the transport phenomena as mediated by electrons and lattice vibrations responsible for superconductivity, Charge Density Waves (CDW) and metal/insulator transitions as function of temperature. The goal of the present work is to develop an understanding of the superconductivity of these selected materials using the transport properties at the fundamental level.

Keywords: Ab initio, high efficiency, power generation devices, transition metal dichalcogenides.

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1157 High Specific Speed in Circulating Water Pump Can Cause Cavitation, Noise and Vibration

Authors: Chandra Gupt Porwal

Abstract:

Excessive vibration means increased wear, increased repair efforts, bad product selection & quality and high energy consumption. This may be sometimes experienced by cavitation or suction/discharge recirculation which could occur only when net positive suction head available NPSHA drops below the net positive suction head required NPSHR. Cavitation can cause axial surging, if it is excessive, will damage mechanical seals, bearings, possibly other pump components frequently, and shorten the life of the impeller. Efforts have been made to explain Suction Energy (SE), Specific Speed (Ns), Suction Specific Speed (Nss), NPSHA, NPSHR & their significance, possible reasons of cavitation /internal recirculation, its diagnostics and remedial measures to arrest and prevent cavitation in this paper. A case study is presented by the author highlighting that the root cause of unwanted noise and vibration is due to cavitation, caused by high specific speeds or inadequate net- positive suction head available which results in damages to material surfaces of impeller & suction bells and degradation of machine performance, its capacity and efficiency too. Author strongly recommends revisiting the technical specifications of CW pumps to provide sufficient NPSH margin ratios >1.5, for future projects and Nss be limited to 8500 - 9000 for cavitation free operation.

Keywords: Best efficiency point (BEP), Net positive suction head NPSHA, NPSHR, Specific Speed NS, Suction Specific Speed Nss.

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1156 A Very High Speed, High Resolution Current Comparator Design

Authors: Neeraj K. Chasta

Abstract:

This paper presents an idea for analog current comparison which compares input signal and reference currents with high speed and accuracy. Proposed circuit utilizes amplification properties of common gate configuration, where voltage variations of input current are amplified and a compared output voltage is developed. Cascaded inverter stages are used to generate final CMOS compatible output voltage. Power consumption of circuit can be controlled by the applied gate bias voltage. The comparator is designed and studied at 180nm CMOS process technology for a supply voltage of 3V.

Keywords: Current Mode, Comparator, High Resolution, High Speed.

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1155 Efficiency Evaluation of E-Commerce Websites

Authors: A. K. Abd El-Aleem, W. F. Abd El-wahed, N. A. Ismail, F. A. Torkey

Abstract:

This study suggests a model of a new set of evaluation criteria that will be used to measure the efficiency of real-world E-commerce websites. Evaluation criteria include design, usability and performance for websites, the Data Envelopment Analysis (DEA) technique has been used to measure the websites efficiency. An efficient Web site is defined as a site that generates the most outputs, using the smallest amount of inputs. Inputs refer to measurements representing the amount of effort required to build, maintain and perform the site. Output is amount of traffic the site generates. These outputs are measured as the average number of daily hits and the average number of daily unique visitors.

Keywords: Data Envelopment Analysis, E-commerce, Efficiency.

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1154 Evaluation of Research in the Field of Energy Efficiency and MCA Methods Using Publications Databases

Authors: Juan Sepúlveda

Abstract:

Energy is a fundamental component in sustainability, the access and use of this resource is related with economic growth, social improvements, and environmental impacts. In this sense, energy efficiency has been studied as a factor that enhances the positive impacts of energy in communities; however, the implementation of efficiency requires strong policy and strategies that usually rely on individual measures focused in independent dimensions. In this paper, the problem of energy efficiency as a multi-objective problem is studied, using scientometric analysis to discover trends and patterns that allow to identify the main variables and study approximations related with a further development of models to integrate energy efficiency and MCA into policy making for small communities.

Keywords: Energy efficiency, MCA, Scientometrics, trends.

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1153 Classifying and Predicting Efficiencies Using Interval DEA Grid Setting

Authors: Yiannis G. Smirlis

Abstract:

The classification and the prediction of efficiencies in Data Envelopment Analysis (DEA) is an important issue, especially in large scale problems or when new units frequently enter the under-assessment set. In this paper, we contribute to the subject by proposing a grid structure based on interval segmentations of the range of values for the inputs and outputs. Such intervals combined, define hyper-rectangles that partition the space of the problem. This structure, exploited by Interval DEA models and a dominance relation, acts as a DEA pre-processor, enabling the classification and prediction of efficiency scores, without applying any DEA models.

Keywords: Data envelopment analysis, interval DEA, efficiency classification, efficiency prediction.

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1152 Study of Energy Efficiency Opportunities in UTHM

Authors: Zamri Noranai, Mohammad Zainal Md Yusof

Abstract:

Sustainable energy usage has been recognized as one of the important measure to increase the competitiveness of the nation globally. Many strong emphases were given in the Ninth Malaysia Plan (RMK9) to improve energy efficient especially to government buildings. With this in view, a project to investigate the potential of energy saving in selected building in Universiti Tun Hussein Onn Malaysia (UTHM) was carried out. In this project, a case study involving electric energy consumption of the academic staff office building was conducted. The scope of the study include to identify energy consumption in a selected building, to study energy saving opportunities, to analyse cost investment in term of economic and to identify users attitude with respect to energy usage. The MS1525:2001, Malaysian Standard -Code of practice on energy efficiency and use of renewable energy for non-residential buildings was used as reference. Several energy efficient measures were considered and their merits and priority were compared. Improving human behavior can reduce energy consumption by 6% while technical measure can reduce energy consumption by 44%. Two economic analysis evaluation methods were applied; they are the payback period method and net present value method.

Keywords: office building, energy, efficiency, economic analyses

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1151 Investigation of Main Operating Parameters Affecting Gas Turbine Efficiency and Gas Releases

Authors: Farhat Hajer, Khir Tahar, Ammar Ben Brahim

Abstract:

This work presents a study on the influence of the main operating variables on the gas turbine cycle. A numerical simulation of a gas turbine cycle is performed for a real net power of 100 MW. A calculation code is developed using EES software. The operating variables are taken in conformity with the local environmental conditions adopted by the Tunisian Society of Electricity and Gas. Results show that the increase of ambient temperature leads to an increase of Tpz and NOx emissions rate and a decrease of cycle efficiency and UHC emissions. The CO emissions decrease with the raise of residence time, while NOx emissions rate increases and UHC emissions rate decreases. Furthermore, both of cycle efficiency and NOx emissions increase with the increase of the pressure ratio.

Keywords: CO, efficiency, gas turbine, NOx, UHC.

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