Search

In this paper, we propose a hybrid CMOS and phase-change memory (PCM)-relaxation-oscillator based circuit for temperature-sensing applications. Unlike conventional CMOS temperature sensors based on ring- or relaxation-oscillators, the proposed sensor does not require any curvature calibration technique for linearity improvement of the thermal response. The presented system explores the temperature dependence of Ovonic-threshold-switching voltage (Vth) and DC OFF state resistance (ROFF) of a PCM device. The proposed temperature sensor exhibits a resolution of ∼0.04 °C (for the 0 °C to 80 °C temperature range) with 0.51 nJ energy consumption per conversion in simulations. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to optimize the consumption of renewable energy and minimize the total cost of system operation, and a combined heat and power unit is added to the wind, water, and water combined dispatching model to solve typical daily dispatch problems in different seasons. Initially, a combined wind–solar–water-fired optimal scheduling model containing cogeneration units and renewable energy preferential consumption is constructed, and the model is solved using particle swarm optimization with the genetic algorithm. The simulation analysis of typical electrical load and heat load during summer and winter in a certain area is implemented as an example to verify the feasibility of the model and algorithm. Compared with the traditional vertical integrated electric-heated coordinated dispatch, the proposed method reflects the willingness of the combined heat and power to actively participate in the paid peak regulation of the power grid under economic incentives. [ABSTRACT FROM AUTHOR]

Green growth has become an increasingly important paradigm for sustainable economic growth, resource development, and environmental protection. As the main focus in energy led green growth is a move away from fossil energy to clean energy, sustainable green growth resource development needs to measure both energy and environmental efficiencies. As the largest global energy consumer and carbon emitter, China has had to deal with serious energy and environmental issues in recent years, with its regional green growth performances being poorly assessed. Therefore, green growth clean energy-environmental efficiency assessments were examined in this paper, for which an integrated principal component analysis-data envelopment analysis based analysis approach was developed. It was found that while China's green growth has had a significant increasing trend in recent years, overall it was still at a low level, with the imbalances in China's regional economic development being reflected in its green growth. However, the excellent development and utilization of clean energy in most regions have significantly promoted a continuous improvement in China's green growth and the move toward sustainable resource development and utilization is contributing to long-term green growth. Green growth has also placed new demands on sustainable resource development in China. Therefore, underdeveloped regions that have sustainable resource endowments need to develop industrial systems that have clean energy as the main axis, and developed regions need to develop high-end industries that have low energy consumption and encourage mutual support systems between regions to ensure optimal sustainable resource, green growth development patterns. [ABSTRACT FROM AUTHOR]

Proof mass can adjust the natural frequency of a cantilevered energy harvester to fit the vibration source frequency and, hence, improve energy efficiency. In this paper, a cantilevered energy harvesting model including a proof mass is presented based on the flexoelectric theory. The electromechanical coupling responses at steady state are obtained for harmonic excitations and then reduced to single-mode expressions for modal excitations. The flexoelectric coupling coefficient, which represents conversion of energy, is investigated. The numerical results reveal that the flexoelectric coupling coefficient can be improved by adjusting the proof mass to make the vibration frequency of the microbeam adapt to that of the ambient vibration source. The adjusting strategies have also been formulated. In addition, the flexoelectric coupling coefficient increases with the decrease in the thickness of the microbeam. As expected, the flexoelectric coupling coefficient can further be enhanced when the beam thickness reaches nanometer scale. For the beam thickness h = 0.3 μm, the current output decreases and the voltage output increases with the increase in the electrical load resistance. When the electrical load resistance is around 100 MΩ, the power output arrives at its maximum. The resonance frequency shifts from 34 693 Hz to 35 350 Hz with the increase in the load resistance from short- to open-circuit conditions, and the flexoelectric coupling coefficient for this thickness lever is kr ≈ 0.19. [ABSTRACT FROM AUTHOR]

This paper presents a new model-free control approach applied to a dynamical fluidic system. The main objective is to evaluate the ability of this closed-loop control technique to control the bistability of a turbulent wake flow past to a square-back Ahmed body. This bistable behavior occurs for some configurations depending mainly on the ground clearance. Due to the unsteady position of the wake vortex cores, the bistable phenomenon is responsible of a strong variation of the lateral force (drift force) and of a slight drag increase. Consequently, mitigating the wake symmetry-breaking modes can induce a substantial drag reduction. The feedback controller controls the drift using its ultralocal approximation and the estimation of its dynamics. The control signal is then applied to lateral blower actuators to suppress the spanwise bistability. The drift force is used as feedback to sense the wake flow, and concomitant velocity, forces, and pressure measurements are performed at a nominal Reynolds number of Reh = 2.86 × 105 to quantify and demonstrate the effectiveness of the present closed-loop control. Results show that for various actuation velocity ratios, the bistability suppression can lead to a drag reduction up to 2.5% with an energy consumption evaluated to be less than 0.6% of the aerodynamic power saving for the worst investigated case. [ABSTRACT FROM AUTHOR]

The photoelectric power conversion efficiency of polymer solar cells is till now, compared to conventional inorganic solar cells, still relatively low with maximum values ranging from 7% to 8%. This essentially relates to the existence of exciton and charge carrier loss phenomena, reducing the performance of polymer solar cells significantly. In this paper we introduce a new computer simulation technique, which permits to explore the causes of the occurrence of such phenomena at the nanoscale and to design new photovoltaic materials with optimized opto-electronic properties. Our approach consists in coupling a mesoscopic field-theoretic method with a suitable dynamic Monte Carlo algorithm, to model the elementary photovoltaic processes. Using this algorithm, we investigate the influence of structural characteristics and different device conditions on the exciton generation and charge transport efficiencies in case of a novel nanostructured polymer blend. More specifically, we find that the disjunction of continuous percolation paths leads to the creation of dead ends, resulting in charge carrier losses through charge recombination. Moreover, we observe that defects are characterized by a low exciton dissociation efficiency due to a high charge accumulation, counteracting the charge generation process. From these observations, we conclude that both the charge carrier loss and the exciton loss phenomena lead to a dramatic decrease in the internal quantum efficiency. Finally, by analyzing the photovoltaic behavior of the nanostructures under different circuit conditions, we demonstrate that charge injection significantly determines the impact of the defects on the solar cell performance. [ABSTRACT FROM AUTHOR]

An experimental investigation is performed on the operation of dielectric barrier discharge plasma actuators used as manipulators of secondary and unsteady flow structures such as boundary layer instabilities or shedding vortices. The actuators are tested mainly in pulse mode. High sample rate hot-wire measurements of the induced velocity field downstream of the actuator are taken for the cases of pulse actuation in still air as well as in a laminar boundary layer. Complementary voltage and current measurements are taken to calculate power consumption. Additionally, a study on the influence of the pulse frequency and duty cycle of actuation is performed. Results show the effectiveness of plasma actuators in inducing fluctuating components of velocity when operated in pulse mode. Spectral analysis reveals the connection between the actuator driving signal and the induced flowfield. The magnitude as well as the consistency of the resulting fluctuating field are dependent on both the duty cycle and the pulse frequency. An empirical operational envelope based on phenomenological observations is proposed, for the use of the actuators at specific flow and operational conditions given in the paper. [ABSTRACT FROM AUTHOR]

This paper presents an evaluation process efficiency based on the consumption of primary energy for all types of practical desalination methods available hitherto. The conventional performance ratio has, thus far, been defined with respect to the consumption of derived energy, such as the electricity or steam, which are susceptible to the conversion losses of power plants and boilers that burned the input primary fuels. As derived energies are usually expressed by the units, either kWh or Joules, these units cannot differentiate the grade of energy supplied to the processes accurately. In this paper, the specific energy consumption is revisited for the efficacy of all large-scale desalination plants. In today's combined production of electricity and desalinated water, accomplished with advanced cogeneration concept, the input exergy of fuels is utilized optimally and efficiently in a temperature cascaded manner. By discerning the exergy destruction successively in the turbines and desalination processes, the relative contribution of primary energy to the processes can be accurately apportioned to the input primary energy. Although efficiency is not a law of thermodynamics, however, a common platform for expressing the figures of merit explicit to the efficacy of desalination processes can be developed meaningfully that has the thermodynamic rigor up to the ideal or thermodynamic limit of seawater desalination for all scientists and engineers to aspire to. [ABSTRACT FROM AUTHOR]

This paper presents a review of recent studies interesting in improving the energy efficiency and cooling quality of refrigeration systems, especially, household refrigerators, air conditioners, and cold storages. They proposed solutions based on renewables such as solar, geothermal, and natural cold through designing advanced plants. Their overall improvement in energy management could bring savings of up to 95% in appropriate conditions and according to the structure of the refrigeration installation. The paper also gives statistics about the energy consumption of refrigeration systems and the interest of using renewables in this field. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model based on energy balance equations of the copper base photovoltaic thermal (PVT) water heating system has been developed. An analytical expression for storage water, outlet water from the PVT collector, and solar cell temperatures has been derived as a function of climatic and design parameters. The developed thermal model has been validated for experimental work carried out for the climatic condition of Chennai, India. Furthermore, the instantaneous thermal energy efficiency is known as a characteristic equation, from which temperature-dependent electrical efficiency and overall thermal and exergy efficiencies have been derived. A fair agreement has been observed between the experimental and theoretical storage water temperatures with a glazing presenting correlation coefficient (r) of 0.999 and a mean square error (e) of 7.48%. It has also been observed that the maximum overall thermal and exergy efficiencies obtained are 33.75% and 14.71%, respectively. [ABSTRACT FROM AUTHOR]

Mobile sensor networks (MSNs) are utilized in many sensing applications that require both target seeking and tracking capabilities. Dynamics of mobile agents and the interactions among them introduce new challenges in designing robust cooperative control mechanisms. In this paper, a distributed semiflocking algorithm inspired by Temnothorax albipennis migration model is proposed to address the above issues. Mobile agents under the control of the proposed semiflocking algorithm are capable of detecting targets faster and tracking them with lower energy consumption when compared with existing MSN motion control algorithms. Furthermore, the proposed semiflocking algorithm can operate energy-efficiently on both flat and uneven terrains. Simulation results demonstrate that the proposed semiflocking algorithm can provide promising performances in target seeking and tracking applications of MSNs. [ABSTRACT FROM AUTHOR]

This paper proposes channel estimation using energy efficient transmission of signal dictionaries for shallow water acoustic communications. Specifically, the multi-columned structure of the channel delay spread is exploited to design partially sampled dictionary in a two-dimensional (2-D) frequency representation of the channel. The key contribution of this work is to achieve considerable energy saving in the transmission of complex exponential signals, designed specifically for real-time shallow water channel estimation at the receiver. This is accomplished by harnessing 2-D frequency localization with compressive transmission and modified-compressive sensing with prior information to exploit the sparse structure of the rapidly fluctuating shallow water acoustic channel in real time. The proposed technique reduces demands on transmitted signal energy by harnessing the reconstruction ability of sparse sensing while retaining key non-sparse channel elements that represent important multipath phenomena. Numerical evidence based on experimental channel estimates demonstrates the efficacy of the proposed work. [ABSTRACT FROM AUTHOR]

As the largest energy consumption country, China now pays more and more attention to photovoltaic power generation because solar energy is the largest renewable and sustainable energy reserve in the world. In this case, the photovoltaic power generation plant project plays a crucial role in sustainable development, especially in the underdeveloped northwest region of China. This paper focuses on applying bi-level programing to the multimode resource-constrained project scheduling problem (MRCPSP) in photovoltaic power generation plant construction, which simultaneously considers the practical hierarchical organization structure and an uncertain decision-making environment. A bi-level fuzzy random multiple objective model is developed, wherein the government agency is in the upper decision level, while the contractor is in the lower decision level. Then, motivated by the particular mathematical nature of the proposed bi-level MRCPSP model, a hybrid intelligent algorithm is designed. Finally, a practical case from the Shenneng Futa Kashi-Tashi-Kuergan photovoltaic power generation plant project in a Chinese energy company is applied, and the results validate the practicability of the proposed model and solution algorithm for solving practical photovoltaic power plant project scheduling problems. [ABSTRACT FROM AUTHOR]

This paper aims to objectively identify the impact of monetary policy on renewable energy enterprises' investment efficiency, further analyze the effectiveness of the Renewable Portfolio Standard, and then put forward some suggestions that are good for the government to implement the monetary policy rationally, guide the direction of renewable energy investment, improve the investment efficiency, and promote the development of the renewable energy industry. We use data on 92 renewable energy listed enterprises in China from the first quarter of 2007 to the third quarter of 2017 as a sample, the Richardson Model to calculate the investment efficiency of related enterprises, and the Regression Discontinuity Model to measure the effectiveness of the Renewable Portfolio Standard. We find that, first, underinvestment is common among China's renewable energy enterprises during the sample period; second, the influence of monetary policy on investment efficiency varies from different transmission channels, and the effect of the credit channel is more significant. The monetary policy status is measured by the growth rate of M2, and the Monetary Policy Perception Index promotes renewable energy enterprises' investment efficiency by 0.3635% and 0.0344%, respectively; they are promoted by 0.8389% and 0.0940%, respectively, through the credit channel; third, easy monetary policy can increase the investment opportunities of renewable energy enterprises in general and then ease their external financing constraints; fourth, the Renewable Portfolio Standard of China promotes the overall renewable energy investment efficiency by 0.2573% and strengthens the promoting effect of monetary policy on renewable energy enterprises' investment efficiency. To some extent, this proves the effectiveness of the policy. [ABSTRACT FROM AUTHOR]

Based on a literature review of the development of new energy, especially the status quo in the development and use of wind energy, this paper analyzed the main factors affecting the development and utilization of wind energy in Jilin Province, China, including law and policy, as well as environmental, economic, social, and industrial factors. The industrial factor mainly involved wind power industry infrastructure, the R&D level of the wind power industry, wind farm construction, and the wind power market. A questionnaire was designed to interview experts and scholars in the field with the help of the Sedentary Time and Activity Reporting Questionnaire network platform. It contained 10 latent variables and 34 measurable indexes and used a Likert-type scale. In total, 368 questionnaires were collected, including 268 valid ones and 100 invalid ones determined by automatic and artificial screening. The AMOS software was used to examine the data and build the structural equation. As a result, the wind power market was found to be the main factor affecting the development level of wind energy in Jilin Province, followed by the economic factor, law and policy, and the environmental factor. It was also found that the main factor hindering the utilization level of wind energy in Jilin Province was infrastructure, which restricted the role of wind energy in promoting economic growth in the province. Therefore, the main problems that urgently need to be solved include speeding up the power grid along with other infrastructure construction. [ABSTRACT FROM AUTHOR]

This paper proposes a DC-linked hybrid renewable energy system (HRES) connected to the grid through a three level neutral point clamped converter. The proposed structure consists of a wind generator (with Maximum Power Point Tracking (MPPT)), power limitation, and pitch control modes) with a flywheel energy storage system, a photovoltaic generator (MPPT and power limitation modes) with a battery, and a super-capacitor connected to each capacitor of the DC link of the three level converter. With the aim of managing the power flow between the HRES, the grid, and the variable load demand, we designed a power management strategy according to the global state of charge of the storage system, the weather conditions, and the load demand. In order to show the efficiency of the proposed structure and management algorithm, numerical simulation was performed using MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

This paper studies the optimum sizing and techno-economic feasibility of photovoltaic systems for rural healthcare building located in a south Indian State, Tamil Nadu, which experiences tropical weather climate. In this study, fixed tilt, annual optimum tilt (AOT), and six other sun tracking installation types are analyzed using hybrid optimization of multiple energy resource (HOMER) energy to understand the power generation potential. As a first step, weekly and monthly optimum tilt angles and AOT are estimated for the study location. The selection of the optimum configuration is arrived with the lowest values of initial cost, operating cost, total net present cost, and levelized cost of energy. It has been found that AOT with fixed installation is the optimum configuration for the study location. However, the performance would vary when the system is put to operate in practical conditions. In order to understand the varying performance, a prototype model is implemented for horizontal axis sun tracking system. The performance of the prototype is analyzed as per the varying real-time weather conditions for four days typically considering the sandstorm day, cloudy day, clear day, and partially cloudy day. [ABSTRACT FROM AUTHOR]

Energy efficiency can be seen as one of the best policies to be adopted by countries to reduce greenhouse gas emissions and for the contribution of the economy. Brazil, despite making some efforts aimed at the rational use of energy, is still far from being a protagonist in this area. On the other hand, countries such as Germany, Japan, and the United States have been adopting policies that aim to improve the use of energy and thus mitigate their greenhouse gas emissions, in addition to expanding the scope of business in this area. In order to achieve greater emphasis in the field of energy efficiency, the objective of this paper is to define energy efficiency policies for food and beverage industry based on international experiences and to measure their impacts in this industry. These policies are represented by technological diffusion curves and their impacts on the reduction of electricity consumption in the food and beverage industry are evaluated. There is a significant reduction in energy consumption and greenhouse gas emissions when adopting energy efficiency policies in this branch of industry, since energy efficiency policies provide an alternative to sustainable development. [ABSTRACT FROM AUTHOR]

The cyclotron-wave rectifier can efficiently convert microwaves into direct current in wireless power transmission. Its resonator operates in the quasi-H111 mode, where there is field non-uniformity; how this field non-uniformity will affect the energy conversion is determined. In this paper, through Computer Simulation Technology simulation, combining experiential analysis with numerical fitting obtains the field expression of the operating mode, approximately calculates the Coulomb field by using the model of a filamentary electron beam, and then through the numerical solution, analyzes the effect of the field non-uniformity on the energy conversion efficiency in both the resonator and the conversion region. The results demonstrate that when the relationship between the beam current I0 and the beam radius robr satisfies the Brillouin relationship, a lesser current density can maintain the beam shape very well and ensure a high beam-wave interaction efficiency; furthermore, in a reverse magnetic field region, when I0 ≤ 0.75Iobr, a higher energy conversion efficiency can be predicted. What is more, the conclusion is in agreement with particle-in-cell simulation. Finally, numerical computation also indicates that high beam-wave interaction efficiency requires a smaller radius of the electron beam. [ABSTRACT FROM AUTHOR]

The design, simulation, fabrication, and experiments of a novel flow sensor based on resonant sensing with a two-stage microleverage mechanism are presented in this paper. Different from the conventional detection methods for flow sensors, two differential resonators are adopted to implement air flow rate transformation through two-stage leverage magnification. The proposed flow sensor has a high sensitivity since the adopted two-stage microleverage mechanism possesses a higher amplification factor than a single-stage microleverage mechanism. The modal distribution and geometric dimension of the two-stage leverage mechanism and hair are analyzed and optimized by Ansys simulation. A digital closed-loop driving technique with a phase frequency detector-based coordinate rotation digital computer algorithm is implemented for the detection and locking of resonance frequency. The sensor fabricated by the standard deep dry silicon on a glass process has a device dimension of 5100 μm (length) × 5100 μm (width) × 100 μm (height) with a hair diameter of 1000 μm. The preliminary experimental results demonstrate that the maximal mechanical sensitivity of the flow sensor is approximately 7.41 Hz/(m/s)2 at a resonant frequency of 22 kHz for the hair height of 9 mm and increases by 2.42 times as hair height extends from 3 mm to 9 mm. Simultaneously, a detection-limit of 3.23 mm/s air flow amplitude at 60 Hz is confirmed. The proposed flow sensor has great application prospects in the micro-autonomous system and technology, self-stabilizing micro-air vehicles, and environmental monitoring. [ABSTRACT FROM AUTHOR]

Integrated energy systems (IESs) have attracted increasing attention in recent years due to the high energy efficiency and low emission of carbon dioxide. To deal with the limitation of single IES, distributed energy networks consisting of multi-IESs are proposed to improve the complementarity of both the energy supply and the demand. This paper mainly focuses on the day-ahead energy management of the whole energy network for the economic operation of the system, following which, a cooperative game is formulated to determine the optimal strategy of each IES to minimize the coalition daily cost. Meanwhile, an allocation mechanism is designed from the perspective of probability to allocate coalition cost to each IES. According to the results of the numerical study, the proposed approach can improve the economic performance of both the energy network and the individual IES by interchanging electrical and thermal energies in the network. [ABSTRACT FROM AUTHOR]

There is an imperative need of developing new strategies and models for meeting the swelling demand of electricity in developing nations like India. One of the promising models for this would be Decentralized Distributed Generation (DDG). DDG locates the power generating source closer to the consumer utilizing locally available Renewable Energy (RE) resources, thereby decreasing the Transmission and Distribution (T&D) losses. Despite the numerous advantages with DDG, there have been some minor issues preventing its large scale deployment and utilization in India. This paper discusses the various technology options which can be used for DDG in India and the problems which the Indian power sector has been facing for a long time. This paper aims to provide a complete analysis of the best possible RE based technology options for DDG in India along with their cost of generation, benefits, barriers, applications, and the possible pathways for its deployment. [ABSTRACT FROM AUTHOR]

This paper presents a small-size permanent magnet generator for an energy harvester. The generator is suitable for a switch, as it uses a magnetic force as the retention force and the force of motion to recognize switch operation. In addition, the induced voltages have positive or negative values depending on the switching direction. It is possible to monitor switch operation for achieving intelligent power consumption. Finally, measurements of the generated voltage are presented to reveal the effectiveness of the energy harvester. [ABSTRACT FROM AUTHOR]

Wind energy sources have grown up from distributed units to large-scale bases which bring a considerable negative impact on power systems. They have taken a significant part in the generation and disturbed the balance between the supply and the load. A system operator has to treat wind power as the stochastic negative loads at times. In essence it is the selective ignorance of the problem. There are rarely proposals of market operations to guide, constrain, and evaluate them efficiently. In this paper, wind energy is integrated into the market where the sources are required to submit the offers of energy and compete with other participants. It is partitioned into base and stochastic parts according to the interval power forecasting. The two parts can be traded in day-ahead and real-time market, respectively, with the support of the storage system. According to the design, the wind energy sources can be well rewarded by the market, and other participants including the agent and the battery energy storage system also benefit from the trading. The simulation has confirmed the feasibility and practicability of the operation. [ABSTRACT FROM AUTHOR]

Energy transportation is an important issue for China's electricity system due to the unbalanced distribution of energy sources and electrical demands. The traditional method of energy transportation (e.g., coal transportation) is challenging due to both the long distance of transportation and the large amount of energy that it requires. In recent years, China has been developing ultra-high voltage (UHV) as an alternative way of transmitting energy over a long distance, and many UHV lines are being planned for construction during the 13th Five-Year Plan (FYP) period. This paper develops a system optimization model for exploring the optimal pathway for long-distance energy transportation in China during the 13th FYP period from the perspective of the minimum cost of an energy transportation system. The results show that (a) although UHV transmission will be increasingly adopted in the 13th FYP period, coal transportation will still play an important role; (b) eight UHV lines are suggested to be built and put into use as a priority in the 13th FYP period; (c) the high technology learning effect, electricity demand, and investment costs of power plants would promote the adoption of UHV. Based on these results, some policy suggestions are provided. [ABSTRACT FROM AUTHOR]

In high energy consumption countries of the world, wind power plant construction plays a significant role in the sustainable development, especially in China. This paper develops a bi-level model based multi-agent system for the decentralized multi-mode resource constrained multi-project scheduling problem (DMRCMPSP) of energy companies, which normally manage several wind power plant construction projects at the same time. In the bi-level DMRCMPSP model, there is an auction agent (AA) in charge of the allocation of global resources in the upper level, while in the lower level, several project agents (PAs) are correspondingly in charge of several projects. The bid and auction mechanism is employed to build up the internal competition, and maximizing self-interest is taken as the objective for both AA and PAs. Finally, a practical application in a Chinese energy company demonstrates the applicability and effectiveness of the proposed methodology. [ABSTRACT FROM AUTHOR]

This paper reports a micro-machined clamped-free semicircular beam resonator aiming to eliminate the nonlinearity that widely exists in traditional mechanical resonators. Cubic coefficients over vibration displacement due to axial extension of the beams are analyzed through theoretical modelling, and the corresponding frequency effect is demonstrated. With the device working in the elastic vibration mode, the cubic coefficients are eliminated by using a free end to release the nonlinear extension of beams and thus the inside axial stress. The amplitude-frequency (A-f) effect is overcome in a large region of source power, and the coefficient of frequency softening is linearized in a large region of polarization voltage. As a result, the resonator can be driven at larger vibration amplitude to achieve a high signal to noise ratio and power handling performance. [ABSTRACT FROM AUTHOR]

To design an effective solar water heating system (SWHS), parameters such as the energy consumption rate, total cost, and climatic region characteristics must be analyzed during the time interval (annual or seasonal) of the predicted use. In this paper, the optimum dimensions of a SWHS were determined using the life cycle cost (LCC) analysis constraint by the 40% solar fraction for the different regions of Turkey for annual and seasonal periods. Particle swarm optimization/Hooke and Jeeves hybrid optimization algorithm was applied. The optimum number of solar collectors and the volume of the hot water storage tank of the SWHS were determined. The optimization process showed that LCC could be reduced for all regions in the range of 3.3%–5.8% in the annual simulation period and 1.8%–4.8% in the period of the summer season simulation. The optimization process carried out in the winter season revealed that the optimization results obtained over different time periods can make a difference in the relations between the optimization parameters. Accordingly, the performance of the SWHS could be improved using a design according to the optimum results obtained at the time interval of the usage. The optimization results obtained in the summer season led to a saving in LCC, while the results obtained in the winter season led to an improvement in the system's thermal performance. Finally, the relative influence of possible operating parameters on an optimum SWHS was investigated through sensitivity analysis. [ABSTRACT FROM AUTHOR]

A novel low power consumption autofocusing actuator in a mini video camera is constructed in accordance with the result of a systematic design procedure of voice coil motors (VCM). This paper emphasizes the position control of such a VCM. The position feedback signals are provided by a magnetoresistive (MR) encoder. The position estimation algorithm (PEA) is developed to precisely decode the MR signals for the position of the moving part of the VCM. Different postures change the loading of the moving part of the VCM, so that an adaptive model-following control system based on the PEA is proposed to compensate for the loading variation. The experiments verify the fast dynamic performance and high power efficiency of the VCM. [ABSTRACT FROM AUTHOR]

Fast linear transformer drivers (FLTDs) are a popular and potential route for high-power devices employing multiple "bricks" in series and parallel, but they put extremely stringent demands on gas switches. Electrode erosion of FLTD gas switches is a restrictive and unavoidable factor that degrades performance and limits stability. In this paper, we systematically investigated the electrode erosion characteristics of a three-electrode field distortion gas switch under the typical working conditions of FLTD switches, and the discharge current was 7-46 kA with 46-300 ns rise time. A high speed frame camera and a spectrograph were used to capture the expansion process and the spectral emission of the spark channel was used to estimate the current density and the spark temperature, and then the energy fluxes and the external forces on the electrode surface were calculated. A tens of kilo-ampere nanosecond pulse could generate a 1011 W/m2 energy flux injection and 1.3-3.5 MPa external pressure on the electrode surface, resulting in a millimeter-sized erosion crater with the maximum peak height Rz reaching 100 μm magnitude. According to the morphological images by a laser scanning confocal microscope, the erosion crater of a FLTD switch contained three kinds of local morphologies, namely a center boiling region, an overflow region and a sputtering region. In addition, the crater size, the surface roughness, and the mass loss were highly dependent on the current amplitude and the transferred charge. We also observed Morphology Type I and Type II, respectively, with different pulse parameters, which had an obvious influence on surface roughness and mass loss. Finally, the quantitative relationship between the electrode mass loss and the pulse parameter was clarified. The transferred charge and the current amplitude were proved to be the main factors determining the electrode mass loss of a FLTD switch, and a least squares fitting expression for mass loss was also obtained. [ABSTRACT FROM AUTHOR]

A novel comprehensive approach to solve a distribution systems' planning problem and to determine the optimal size, location, and technology of the distributed generation (DG) units with respect to the reliability of the system is presented in this paper. The objective functions of this optimization problem are power losses, DGs installation and operation costs, the DG owner's and the Distribution Company's profits as economic objectives. In the proposed method, new indices are defined to evaluate the reliability of the system. These indices calculate energy not supplied and volt ampere reactive not supplied due to active and reactive power shortages. Also, the average interruption frequency (AIF) and average interruption duration (AID) have been considered be minimized during optimization problem. The last two (AIF and AID) are modeled by the adequacy transition rate of DGs among states and are combined as a new objective function. To handle several objective functions, an adaptive fuzzy interactive multi-objective optimization method is used. The results on the IEEE 34-bus and 69-bus power distribution system showed the efficiency of proposed indices for reliability assessment of distribution system planning. [ABSTRACT FROM AUTHOR]

Technological advances for low power consumption and flexible electronics have spurred research on energy harvesting. In this paper, an innovative methodology is proposed to power an ultra-low power wireless sensor node (milliwatt level) autonomously by using a piezoceramic patch which is bonded to a low-frequency vibrating beam. An LTC3588 based energy harvesting module was developed to transfer and collect the energy efficiently. Through a switching interface between the energy harvesting module and the wireless sensor, a 0.33F supercapacitor was charged for 12 h by the harvested vibrational energy to allow the wireless sensor node to join the network and transmit data packets. It was experimentally demonstrated that this applied switching interface could effectively provide on-off control to the power of the wireless sensor node. In order to allow this function, the supercapacitor worked alternatively in the charging mode and the discharging mode. When the supercapacitor stored enough harvested energy, the wireless sensor node initiated the effort to join the wireless network automatically and then sent data packets to the network manager which was connected to a monitoring computer. In addition, wireless sensors which were powered by the energy harvesting system could also send or receive data packets in the network. The developed piezoceramic based energy harvesting method has the potential to be used in structural health monitoring systems by harvesting the ambient mechanical energy. [ABSTRACT FROM AUTHOR]

This paper presents detailed energy and exergy analysis and comparison of low-grade solar heat source powered superheated and saturated organic Rankine cycle (ORC) using zeotropic mixture butane/R1234ze. The required expression to evaluate the power output, first law efficiency exergetic efficiency, exergy destruction, and required heat exchangers area are coded in Matlab 2015a interfaced with REFPROP 9.0. Moreover, saturated and superheated ORCs are further optimized by genetic algorithm by selecting exergetic efficiency and product of overall heat transfer coefficient and heat exchanger area. It is observed that superheated ORC exhibits better net power output, first law and exergetic efficiency, lower exergy destruction and poorer economy than saturated ORC. Further, the performance of saturated ORC is increased by 34.02% and that of superheated ORC by 17.06% by the multiobjective genetic algorithm. [ABSTRACT FROM AUTHOR]

The energy balance of the black liquor gasification (BLG) system, which is the core part in the Pulp-Syngas-Heat and Electricity combined cycle system, was analysed in this paper. Based on existing engineering parameters, we compared the energy consumption, conversion efficiency and energy cost of the BLG system under the different process conditions, in particular the air separation and concentration sections. Comparative analysis of these critical processes would facilitate the optimization of energy conversion efficiency and energy cost, as well as ascertain the influence of electricity and heat price on them. Results showed the drive combination of mechanical vapour recompression concentrating black liquor and electric driven preparation of oxygen (MVR-Motor) had the highest energy conversion efficiency of 73.18% but maximal energy cost. The drive combination of multi-effect evaporation concentrating black liquor and back pressure steam turbine preparation of oxygen (MEE-BPST) had the lowest energy cost, despite its energy conversion efficiency a little lower than MVR-Motor. For the drive combination of MVR-Motor, BLG system can get 224.32 kgce net energy output per 1000 kg straw pulp. Selection of reasonable process technology would promote the commercialization of BLG and the links to paper industry, biomass energy industry, and chemical industry, which benefits the control of black liquor pollution. [ABSTRACT FROM AUTHOR]

This paper presents the operation and optimisation of a smart multi-energy hub system network using the energy hub concept. The case study system network includes integrated solar photovoltaic and thermal power generation units and natural gas combined heat and power unit systems. A demand response-dynamic economic emission optimisation model is applied in the case study and allows for a comparison of energy hub control strategies including the evaluation of economic and environmental criteria and power import between energy hubs. The results show a significant reduction of more than 50% in both the total generation cost and amount of emission when different energy hub control strategies are employed. The results also show that load shifting capabilities of different energy hub loads cannot be ignored as they reduce the electricity bill of energy hub customers. [ABSTRACT FROM AUTHOR]

Conventional energy sources are limited, whereas the energy demand is increasing exponentially. There is immediate need to develop efficient systems to extract more useful energy from the same fuel input. Cogeneration and trigeneration systems use waste heat from prime movers to produce more useful energy than conventional methods in the form of heat and cooling. In this paper, an experimental and simulation based study of compression ignition engine operated micro-cogeneration and trigeneration systems working on diesel and other vegetable oil based fuel derivatives is presented. The energy and exergy analyses of both the cogeneration and trigeneration systems were done. The results obtained with base line diesel show that the overall thermal efficiency was 79.43% for cogeneration and 78.64% for trigeneration. The exergy effi- ciency of the system was found to be 32.80% for cogeneration and 33.08% for trigeneration. The system was modeled and simulated using TRNSYS, and the simulation results were compared with the experimental results for the validation. The improved system model for trigeneration was developed using TRNSYS to determine the scope for improvement, and it was found that it achieved the energy efficiency of 89.20% and the exergy efficiency of 45.94%. [ABSTRACT FROM AUTHOR]

In this paper, the characteristics and dispersity of a two gap capillary (TGC) discharge applied for long spark gap ignition are studied. Under the same discharge condition, 30 repetitive discharges are done to get a certain number of data samples. Accordingly, the change trend of the characteristics and the dispersity with the charging voltage of C1 are analyzed statistically. The delay of soft capillary discharge is determined by the saturation rate of the magnetic core of the pulse transformer and decreases with the increase in the charging voltage. The main discharge delay decreases from 1.0 kV to 2.0 kV and stops the decreasing trend when the charging voltage increases to 2.5 kV. In contrast, the current amplitude of soft capillary discharge and main discharge increases with charging voltage. Long tail extinction is witnessed at the charging voltage of 1.0 kV and the major cause is the insufficient pressure in the post discharge. The waveform of the capillary arc resistivity is U-like shape and the minimum resistivity decreases with the increase in the charging voltage. Meanwhile, the arc resistivity in the ascending stage is much higher than that in the descending stage with the same value of the discharge current. The energy consumption of the TGC discharge can be mainly divided into four parts and more than 70% of the energy is consumed in main discharge. [ABSTRACT FROM AUTHOR]

Tibet is located in the southwest of China, with unique geographical conditions and natural resources, new energy reserves like solar energy and wind resources are in the forefront of other provinces in China, and it is also one of the solar energy resource richest regions in the world. Since central Tibet is the economic center of the Tibet autonomous region and Lhasa is the outside sending end of Qinghai-Tibet DC, developing new energy resources in central Tibet would play an important role in inter-provincial delivery of renewable energy power generation, reducing fossil energy consumption to achieve a clean alternative and stimulating the economic growth of Tibet. In this paper, the renewable energy consumptive situation in central Tibet was studied. Through the analysis of renewable energy reserves, distribution and utilization, the current situation of the renewable energy development and the electricity load in Tibet, the solutions and suggestions for new energy generation consumption were put forward in the end. [ABSTRACT FROM AUTHOR]

Micro-grids are small-scale grids, equipped with energy management and on-site energy generation. They offer low-cost power to consumers and combined with green energy, they are a promising solution to build the future smart city. This paper discusses the different components of a micro-grid and their mathematical equations. The model is built in Matlab/Simulink and respects the distribution rules of the Moroccan grid code. The modeled residential group represents the power consumption of an average Moroccan household in the mountainous region of Ifrane. Two simulation scenarios were designed in order to validate the model. The first scenario tests the microgrid during normal operation, while the second scenario introduces a grid fault, requiring disconnection from the utility grid. Simulation results show that the model responds to the specified weather and system conditions as predicted. [ABSTRACT FROM AUTHOR]

Electric load forecasting, as a crucial way to tackle the energy tasks, helps to provide correct guidance and reduce energy consumption for an electric system. This paper introduces a novel forecasting method that combines wavelet transform (WT) and particle swarm optimization (PSO) with an extreme learning machine, phase space reconstruction (PSR) and a least squares support vector machine. Because the electric data that are easily interfered by many factors are unstable, directly adopting the data containing noise will affect the forecasting performance. Prior to the electric forecasting conduct, WT is adopted to reduce the noise. Because only a single method is not able to suit for all kinds of data, three individual models with a strong nonlinear learning capability are applied to deal with the whole time series that have complex nonlinear characteristics. They are used to obtain intermediate forecasting results. Besides, the C-C method is utilized to acquire the optimal delay time and embedding dimension of the PSR. PSO is employed to attain the best proportion of each single method of the hybrid model. By multiplying the corresponding optimal weights by all the three forecasting results and then adding them up, the final result of the hybrid method can be attained. In order to assess the accuracy and applicability of the proposed hybrid method, half-hourly electric load data of New South Wales and Victoria of Australia are used as case studies. The experiment results show that the hybrid method outperforms the individual methods and is appropriate for different kinds of data. [ABSTRACT FROM AUTHOR]

As a non-Annex I country, Thailand has pledged its intended nationally determined contribution (INDC) to reduce greenhouse gas emissions by 20% from the projected business-as-usual (BAU) level by 2030 and by up to 25% with adequate and enhanced access to technology development and transfer, financial resources and capacity building support. The purpose of this paper is to investigate how these targets could possibly be met, as far as energy-related CO2 emissions are concerned and to propose alternative pathways for fast transition to a low-carbon and cleaner energy system along with its technology and research requirements. The study approach is based on the 6th Edition of APEC Energy Outlook for 2040 and the energy-related CO2 emissions scenarios developed at the Asia Pacific Energy Research Centre. It is found that Thailand's voluntary INDC target on energy-related emissions could be achieved by a combination of energy efficiency improvement efforts and deployment of renewable energy in line with their respective official plans. The higher conditional INDC target of 25% could also be reached by a natural gas dominated power sector, in addition to energy efficiency and renewable energy deployment measures, at the risk of worsening its energy security and increased cost of electricity. An alternative scenario that would not only meet the conditional INDC target but also lead to a fast transition towards a low-carbon and cleaner energy system by 2040 is possible. The scenario is based on a balanced approach, taking into account energy security, cost and environment. It requires ambitious energy efficiency improvement (particularly in the transport sector) and renewable energy targets and significant de-carbonization of the power sector. The scenario will see Thailand's energy-related CO2 emissions peaking around 2030 and a 45% cut below the projected BAU level in 2040. The technologies and research required to support the transition have also been identified for the power, transport, commercial buildings and industry sectors. [ABSTRACT FROM AUTHOR]

The terahertz surface wave oscillator (SWO) faces the problem of the low energy conversion efficiency due to the fact that working mode is the surface wave but the output mode is the volume wave, and it is very difficult to extract the terahertz wave efficiently. In the meantime, the possibility of the RF breakdown increases as a result of the intense electric field on the surface of slow wave structures (SWSs). To overcome these problems, the field distribution in the SWSs of the 0.147 THz relativistic SWO is analyzed in this paper, and the results indicate that the electric field distribution in the SWSs is similar to that in spoof surface plasmon polaritons (SSPPs). In order to improve the energy conversion efficiency of the SWO, we propose to adopt the circular SSPP coupler with tapered gratings at the end of the uniform SWSs, which is implemented to smoothly bridge the surface wave and guided wave. Second, the SWO with the coupler is simulated using particle-in-cell code UNIPIC. The simulation results indicate that the output terahertz power enhances 52% after the SSPP coupler is used. More importantly, the numerical results demonstrate that the intensity of the electric field decreases 25% on the corrugation surface of the SWSs, so the RF breakdown can be avoided in the terahertz relativistic SWO. [ABSTRACT FROM AUTHOR]

Electric discharge in liquids is an emerging field of research, and is involved into various environmental applications (water purification, fuel reforming, nanomaterial synthesis, etc.). Increasing the treatment efficiency with simultaneous decreasing of the energy consumption are the main goals of today's research. Here we present an experimental study of nanosecond discharge in distilled water covered by a layer of dielectric material. We demonstrate through this paper that the discharge efficiency can be improved by changing the interface position regarding the anode tip. The efficiency increase is due to the increase of the discharge probability as well as the plasma volume. The understanding of the experimental results is brought and strengthened by simulating the electric field distribution, using Comsol Multiphysics software. Because the dielectric permittivity (ε) is discontinuous at the interface, the electric field is enhanced by a factor that depends on the relative value of " of the two liquids. The present result is very promising in future: opportunities for potential applications as well as fundamental studies for discharges in liquid. [ABSTRACT FROM AUTHOR]

This paper reports radiation characteristics of input power from a surface wave sustained plasma antenna investigated theoretically and experimentally, especially focusing on the power consumption balance between the plasma generation and the radiation. The plasma antenna is a dielectric tube filled with argon and small amount of mercury, and the structure is a basic quarter wavelength monopole antenna at 2.45GHz. Microwave power at 2.45 GHz is supplied to the plasma antenna. The input power is partially consumed to sustain the plasma, and the remaining part is radiated as a signal. The relationship between the antenna gain and the input power is obtained by an analytical derivation and numerical simulations. As a result, the antenna gain is kept at low values, and most of the input power is consumed to increase the plasma volume until the tube is filled with the plasma whose electron density is higher than the critical electron density required for sustaining the surface wave. On the other hand, the input power is consumed to increase the electron density after the tube is fully filled with the plasma, and the antenna gain increases with increasing the electron density. The dependence of the antenna gain on the electron density is the same as that of a plasma antenna sustained by a DC glow discharge. These results are confirmed by experimental results of the antenna gain and radiation patterns. The antenna gain of the plasma is a few dB smaller than that of the identical metal antenna. The antenna gain of the plasma antenna is sufficient for the wireless communication, although it is difficult to substitute the plasma antenna for metal antennas completely. The plasma antenna is suitable for applications having high affinity with the plasma characteristics such as low interference and dynamic controllability. [ABSTRACT FROM AUTHOR]

With continuous global revolution toward the creation of a green environment, it is ardently necessary to eliminate all possible scopes of energy waste and leakage during the standby or inactive mode of operation. The magnitude of standby energy loss happening in all kinds of electronic and electrical systems is a global concern for scientists and engineers. A global picture of standby power consumption and reduction effort is elaborated in this paper. Approximate charts of standby power loss in majority of the electrical and electronic appliances are tabulated here. Numerous sources of energy losses in standby modes are identified in this paper. Some illustrations are made regarding the technical steps to be adhered to minimize the inactive mode power consumption. Power supplies that are the major contributors of energy waste are identified here. Various procedures and approaches are suggested, which would lead to standby power reduction and thereby would produce mode energy efficient systems. These corrective measures if properly implemented universally in both domestic as well as industrial appliances would save immense energy count and hence would reduce the global demand of energy. [ABSTRACT FROM AUTHOR]

On the way towards high memory density and computer performance, a considerable development in energy efficiency represents the foremost aspiration in future information technology. Complementary resistive switch consists of two antiserial resistive switching memory (RRAM) elements and allows for the construction of large passive crossbar arrays by solving the sneak path problem in combination with a drastic reduction of the power consumption. Here we present a titanium oxide based complementary RRAM (CRRAM) device with Pt top and TiN bottom electrode. A subsequent post metal annealing at 400°C induces CRRAM. Forming voltage of 4.3 V is required for this device to initiate switching process. The same device also exhibiting bipolar switching at lower compliance current, Ic <50 μA. The CRRAM device have high reliabilities. Formation of intermediate titanium oxi-nitride layer is confirmed from the cross-sectional HRTEM analysis. The origin of complementary switching mechanism have been discussed with AES, HRTEM analysis and schematic diagram. This paper provides valuable data along with analysis on the origin of CRRAM for the application in nanoscale devices. [ABSTRACT FROM AUTHOR]

Battery Energy Storage System (BESS) is a type of clean energy, which is able to enhance energy efficiency. However, the connection of the BESS with distribution systems has an impact on the conventional protection. This paper presents the BESS operation characteristics and its impact on distance protection. Optimal strategy of Zone II is analyzed from the perspective of impedance originally. The BESS has three operation statuses which will be studied separately. When a fault occurs at different locations of feeders downstream, the fault current of the BESS increases nonlinearly. By defining two original concepts, critical impedance and maximum protection impedance, the nonlinear output current is classified into two parts. Protect access capacity and protection sensitivity are analyzed under both situations. Modifying value m is presented to solve this protection-related problem. Minimum and maximum values of m are calculated to avoid overreach or blinding operation. After optimized by m, Zone II protection can trip correctly. Analysis and simulation results, based on two practical distribution systems, verified the effectiveness of the optimization strategy. [ABSTRACT FROM AUTHOR]

Growing demand of energy consumption, subsequent increase in energy generation costs, and increased greenhouse gas (GHG) emissions, as well as global warming from the conventional energy sources, encourages interest worldwide to bring a higher percentage of renewable energy sources such as biogas into the energy mix to build a climate friendly environment for the future. Moreover, due to high investment and maintenance costs, governments are not providing enough support for grid extension and delivering electricity to remote locations or rural areas, in particular, in under-developing countries like Bangladesh. Therefore, this paper presents an Energy Neutral Home System (ENHS) that can meet all its energy requirements from low-cost, locally available, nonpolluting biogas generated from animal waste, in particular, chicken and cow manure. The proposed ENHS has been developed for rural community, typically an area of 200 families, and will not only provide cooking gas and sustainable and affordable power supply to the community with low emissions, but will also facilitate high quality fertilizer for agricultural purposes. In-depth analysis clearly demonstrates that the proposed ENHS not only offers electricity and cooking gas to the community with the lowest costs, but also reduces the energy crisis and GHG emissions and can play an active role in developing socio-economic infrastructure of rural communities in Bangladesh in many ways. [ABSTRACT FROM AUTHOR]

In this paper, a double-glazed solar air heater (SAH) using paraffin wax as phase change material (PCM) was designed, fabricated, and tested under the climatic condition of Mashhad, Iran (latitude, 37° 280 N and longitude, 57° 200 E) during three typical days in the summer. The PCM stores solar radiation of the sun as latent and sensible heat during daytime and then restores such stored energy during the night. Exploitation of both first and second laws of Thermodynamics, the energy and exergy efficiencies of this system are assessed. According to the experiments undertaken, it is found that the daily energy efficiency of the system varies between 58.33% and 68.77%, whereas the daily exergy efficiency varies from 14.45% to 26.34%. Eventually, the economic analysis shows that the cost of 1 kg of heated air utilizing double-glazed SAH would be 0.0036$. [ABSTRACT FROM AUTHOR]

In this paper, the energy efficiency of airlines is measured. Number of employees and tons of aviation kerosene are chosen as the inputs. Revenue tonne kilometers, revenue passenger kilometers, and total business income are the outputs. Capital stock is selected as the dynamic factor. A new model, Virtual Frontier Dynamic range adjusted measure (RAM), is proposed to calculate the energy efficiencies of 22 airlines from 2008 to 2012. In Virtual Frontier Dynamic RAM, the reference DMU (decision-making unit) set and the evaluated DMU set are two different sets to distinguish between efficient DMUs. The results demonstrate the following: (1) Air Greenland exhibits the highest energy efficiency, while the efficiency score of Air France-KLM is at the bottom of the 22 airlines. (2) Aggregate airline energy efficiency consistently increased from 2008 to 2012. [ABSTRACT FROM AUTHOR]