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Application of metal oxides-based nanofluids in PV/T systems: a review

《能源前沿(英文)》 2022年 第16卷 第3期   页码 397-428 doi: 10.1007/s11708-021-0758-8

摘要: Having the wide application of metal oxides in energy technologies, in recent years, many researchers tried to increase the performance of the PV/T system by using metal oxide-based nanofluids (NFs) as coolants or optical filters or both at the same time. This paper summarizes recent research activities on various metal oxides (Al2O3, TiO2, SiO2, Fe3O4, CuO, ZnO, MgO)-based NFs performance in the PV/T system regarding different significant parameters, e.g., thermal conductivity, volume fraction, mass flowrate, electrical, thermal and overall efficiency, etc. By conducting a comparative study among the metal oxide-based NFs, Al2O3/SiO2-water NFs are mostly used to achieve maximum performance. The Al2O3-water NF has a prominent heat transfer feature with a maximum electrical efficiency of 17%, and a maximum temperature reduction of PV module of up to 36.9°C can be achieved by using the Al2O3-water NF as a coolant. Additionally, studies suggest that the PV cell’s efficiency of up to 30% can be enhanced by using a solar tracking system. Besides, TiO2-water NFs have been proved to have the highest thermal efficiency of 86% in the PV/T system, but TiO2 nanoparticles could be hazardous for human health. As a spectral filter, SiO2-water NF at a size of 5 nm and a volume fraction of 2% seems to be very favorable for PV/T systems. Studies show that the combined use of NFs as coolants and spectral filters in the PV/T system could provide a higher overall efficiency at a cheaper rate. Finally, the opportunities and challenges of using NFs in PV/T systems are also discussed.

关键词: metal oxide     nanofluids (NFs)     nanoparticles (NPs)     optical filter     PV/T systems     solar energy    

PV/T太阳能热泵系统的性能研究

裴刚,季杰,何伟,孙炜

《中国工程科学》 2006年 第8卷 第9期   页码 49-56

摘要:

提出一种新型的太阳能热泵系统——PV/T-SAHP系统,该系统具有光电/光热综合利用的功能;建立了PV/T-SAHP系统的动态模型,对该系统的运行特性进行了数值模拟。结果显示,PV/T-SAHP系统的电效率和热效率较传统的太阳能系统和热泵系统都有明显提高,运行能耗较普通热泵大幅度降低;系统PV/T蒸发器的面积、管间距、倾角等参数的变化对电效率和热性能会产生比较大的影响

关键词: 太阳能热泵     光电光热综合利用     PV/T     SAHP    

Performance enhancement of partially shaded solar PV array using novel shade dispersion technique

Namani RAKESH,T. Venkata MADHAVARAM

《能源前沿(英文)》 2016年 第10卷 第2期   页码 227-239 doi: 10.1007/s11708-016-0405-y

摘要: Solar photo voltaic array (SPVA) generates a smaller amount of power than the standard rating of the panel due to the partial shading effect. Since the modules of the arrays receive different solar irradiations, the P-V characteristics of photovoltaic (PV) arrays contain multiple peaks or local peaks. This paper presents an innovative method (magic square) in order to increase the generated power by configuring the modules of a shaded photovoltaic array. In this approach, the physical location of the modules in the total cross tied (TCT) connected in the solar PV array is rearranged based on the magic square arrangement pattern. This connection is done without altering any electrical configurations of the modules in the PV array. This method can distribute the shading effect over the entire PV array, without concentrating on any row of modules and can achieve global peaks. For different types of shading patterns, the output power of the solar PV array with the proposed magic square configuration is compared with the traditional configurations and the performance is calculated. This paper presents a new reconfiguration technique for solar PV arrays, which increases the PV power under different shading conditions. The proposed technique facilitates the distribution of the effect of shading over the entire array, thereby, reducing the mismatch losses caused by partial shading. The theoretical calculations are tested through simulations in Matlab/Simulink to validate the results. A comparison of power loss for different types of topologies under different types of shading patterns for a 4 × 4 array is also explained.

关键词: photovoltaic cells     mismatch loss     shading patterns     partial shading     magic square     power enhancement     global peaks and total cross tied (TCT)    

Requirements in performance measurement systems of construction projects from the lean production perspective

BARTH, Carlos T. FORMOSO

《工程管理前沿(英文)》 2021年 第8卷 第3期   页码 442-455 doi: 10.1007/s42524-020-0108-2

摘要: Performance measurement (PM) generates useful data for process control, facilitates communication between different sectors, and helps to align efforts on the most important aspects of the business. Thus, PM plays a key role in the management of projects and organizations. PM is also important in the implementation of lean production principles and methods, such as reducing the share of nonvalue-adding activities, increasing process transparency, building continuous improvement into the process, and benchmarking. Moreover, the adoption of the lean production philosophy requires changes in PM. Despite its importance, limited studies have been conducted on the use of PM systems for assessing the impact of lean production programs in construction projects. In addition, studies on how lean companies (or projects) use performance measurement and to what extent the indicators adopted reflect the result of actions that have been undertaken are limited. This study proposes a set of requirements in PM systems of construction projects from the perspective of lean production and a taxonomy of performance metrics for lean production systems. Five empirical studies have been carried out on construction companies from South America involved in the implementation of lean production systems. The scope of this investigation is limited to the construction projects as production systems rather than PM at the level of construction organizations.

关键词: performance measurement     lean construction     production management     continuous improvement     metrics    

A new method for estimating the longevity and degradation of photovoltaic systems considering weather

Amir AHADI,Hosein HAYATI,Joydeep MITRA,Reza ABBASI-ASL,Kehinde AWODELE

《能源前沿(英文)》 2016年 第10卷 第3期   页码 277-285 doi: 10.1007/s11708-016-0400-3

摘要: The power output of solar photovoltaic (PV) systems is affected by solar radiation and ambient temperature. The commonly used evaluation techniques usually overlook the four weather states which are clear, cloudy, foggy, and rainy. In this paper, an ovel analytical model of the four weather conditions based on the Markov chain is proposed. The Markov method is well suited to estimate the reliability and availability of systems based on a continuous stochastic process. The proposed method is generic enough to be applied to reliability evaluation of PV systems and even other applications. Further aspects investigated include the new degradation model for reliability predication of PV modules. The results indicate that the PV module degradation over years, failures, and solar radiation must be considered in choosing an efficient PV system with an optimal design to achieve the maximum benefit of the PV system. For each aspect, a method is proposed, and the complete focusing methodology is expounded and validated using simulated point targets. The results also demonstrate the feasibility and applicability of the proposed method for effective modeling of the chronological aspects and stochastic characteristics of solar cells as well as the optimal configuration and sizing of large PV plants in terms of cost and reliability.

关键词: photovoltaic (PV) systems     solar cell     Markov model     weather effects    

Resiliency of steel and composite structures

Roberto T. LEON,Yu GAO

《结构与土木工程前沿(英文)》 2016年 第10卷 第3期   页码 239-253 doi: 10.1007/s11709-016-0349-7

摘要: This paper is divided into two parts. The first part addresses the resiliency and sustainability of steel and composite structures from a fundamental standpoint, and it is intended as an introduction to the other six papers that form part of this issue related to resiliency of steel structural systems in seismic areas. The paper posits the idea that resiliency is a characteristic that embodies sustainability rather than the traditional opposite point of view. The second part of the paper is divided into two sections, with the first section describing a number of retrofit technologies with recentering characteristics that have been developed for small, seismically deficient buildings in developing countries. The second section describes an innovative connection between circular concrete filled tubes and conventional beams with reduced flange sections consisting of steel and shape memory alloy bars and end plates. The connection has partial restraint behavior and strong recentering properties. This connection is used to demonstrate that some creative thinking can lead to innovative ways of addressing issues related to robustness, resiliency and sustainability of steel structures.

关键词: steel structures     resiliency     sustainability     recentering systems     shape memory alloys    

Fault classification and reconfiguration of distribution systems using equivalent capacity margin method

Sathish KUMAR, T. JAYABARATHI

《能源前沿(英文)》 2012年 第6卷 第4期   页码 394-402 doi: 10.1007/s11708-012-0211-0

摘要: This paper investigates the capability of support vector machines (SVM) for prediction of fault classification and the use of the concept of equivalent capacity margin (ECM) for restoration of the power system. The SVM, as a novel type of machine learning based on statistical learning theory, achieves good generalization ability by adopting a structural risk minimization (SRM) induction principle aimed at minimizing a bound on the generalization error of a model rather than the minimization of the error on the training data only. Here, the SVM has been used as a classification. The inputs of the SVM model are power and voltage values. An equation has been developed for the prediction of the fault in the power system based on the developed SVM model. The next steps of this paper are the restoration and reconfiguration by using the ECM concept, the development of a code, and the testing of the results with various load outages, which have been executed for a 12 load system.

关键词: support vector machines (SVM)     structural risk minimization (SRM)     equivalent capacity margin (ECM)     restoration     fault classification    

Life cycle cost savings analysis on traditional drainage systems from low impact development strategies

Pengfei ZHANG, Samuel T. ARIARATNAM

《工程管理前沿(英文)》 2021年 第8卷 第1期   页码 88-97 doi: 10.1007/s42524-020-0063-y

摘要: Areas that are covered with natural vegetation have been converted into asphalt, concrete, or roofed structures and have increased surface impermeability and decreased natural drainage capability. Conventional drainage systems were built to mimic natural drainage patterns to prevent the occurrence of waterlogging in developed sites. These drainage systems consist of two major components: 1) a stormwater conduit system, and 2) a runoff storage system. Runoff storage systems contain retention basins and drywells that are used to store and percolate runoff, whereas conduit systems are combination of catch basins and conduit pipes used to collect and transport runoff. The construction of these drainage systems is costly and may cause significant environmental disturbance. In this study, low impact development (LID) methods that consist of extensive green roofs (GRs) and permeable interlocking concrete pavements (PICPs) are applied in real-world construction projects. Construction project documents were reviewed, and related cost information was gathered through the accepted bidding proposals and interviews of specialty contractors in the metropolitan area of Phoenix, Arizona. Results indicate that the application of both LID methods to existing projects can save an average of 27.2% in life cycle costs (LCC) for a 50-year service life and 18.7% in LCC for a 25-year service life on the proposed drainage system, respectively.

关键词: low impact development     traditional drainage system     hydraulic benefits     life-cycle cost    

State-of-art review of the optimization methods to design the configuration of hybrid renewable energy systems

Maurizio FACCIO, Mauro GAMBERI, Marco BORTOLINI, Mojtaba NEDAEI

《能源前沿(英文)》 2018年 第12卷 第4期   页码 591-622 doi: 10.1007/s11708-018-0567-x

摘要: The current research aims to present an inclusive review of latest research works performed with the aim of improving the efficiency of the hybrid renewable energy systems (HRESs) by employing diverse ranges of the optimization techniques, which aid the designers to achieve the minimum expected total cost, while satisfying the power demand and the reliability. For this purpose, a detailed analysis of the different classification drivers considering the design factors such as the optimization goals, utilized optimization methods, grid type as well as the investigated technology has been conducted. Initial results have indicated that of all optimization goals, load demand parameters including loss of power supply probability (LPSP) and loss of load probability (LLP), cost, sizing (configuration), energy production, and environmental emissions are the most frequent design variables which have been cited the most. Another result of this paper indicates that almost 70% of the research projects have been dedicated toward the optimization of the off-grid applications of the HRESs. Furthermore, it has been demonstrated that, integration of the PV, wind and battery is the most frequent configuration. In the next stage of the paper, a review concerning the sizing methods has also been carried out to outline the most common techniques which are used to configure the components of the HRESs. In this regard, an analysis covering the optimized indicators such as the cost drivers, energy index parameters, load indicators, battery’s state of charge, PV generator area, design parameters such as the LPSP, and the wind power generation to load ratio, has also been performed.

关键词: hybrid renewable energy systems (HRESs)     design and optimization     environmental pollutions     PV array     wind turbines (WTs)     inverter     diesel generator (DG)    

Potential and economic viability of standalone hybrid systems for a rural community of Sokoto, North-west

O. D. OHIJEAGBON,Oluseyi. O AJAYI

《能源前沿(英文)》 2014年 第8卷 第2期   页码 145-159 doi: 10.1007/s11708-014-0304-z

摘要: An assessment of the potential and economic viability of standalone hybrid systems for an off-grid rural community of Sokoto, North-west Nigeria was conducted. A specific electric load profile was developed to suite the community consisting 200 homes, a school and a community health center. The data obtained from the Nigeria Meteorological Department, Oshodi, Lagos (daily mean wind speeds, and daily global solar radiation for 24 years from 1987 to 2010) were used. An assessment of the design that will optimally meet the daily load demand with a loss of load probability (LOLP) of 0.01 was performed, considering 3 stand-alone applications of photovoltaic (PV), wind and diesel, and 3 hybrid designs of wind-PV, wind-diesel, and solar-diesel. The diesel standalone system (DSS) was taken as the basis of comparison as the experimental location has no connection to a distribution network. The HOMER® software optimizing tool was engaged following the feasibility analysis with the RETScreen software. The wind standalone system (WSS) was found to be the optimal means of producing renewable electricity in terms of life cycle cost as well as levelised cost of producing energy at $0.15/(kW·h). This is competitive with grid electricity, which is presently at a cost of approximately $0.09/(kW·h) and 410% better than the conventional DSS at a levelized cost of energy (LCOE) of $0.62/kWh. The WSS is proposed for communities around the study site.

关键词: photovoltaic (PV) power     wind power     solar-wind hybrid     cost per kilowatt-hour     clean energy    

Distribution and temporal variability of the solar resource at a site in south-east Norway

Muyiwa S. ADARAMOLA

《能源前沿(英文)》 2016年 第10卷 第4期   页码 375-381 doi: 10.1007/s11708-016-0426-6

摘要: Globally, solar energy is expected to play a significant role in the changing face of energy economies in the near future. However, the variability of this resource has been the main barrier for solar energy development in most locations around the world. This paper investigated the distribution and variability of solar radiation using the a 10-year (2006 to 2015) data collected at Sørås meteorological station located at latitude 59° 39′ N and longitude 10° 47′E, about 93.3 m above sea level (about 30 km from Oslo), in south-eastern part of Norway. It is found that on annual basis, the total number of days with a global solar radiation of less than 1 kWh/(m ·d) is 120 days while the total number of days with an expected global solar radiation greater than 3 kWh/(m ·d) is 156 days (42.74%) per year. The potential energy output from a horizontally placed solar collector in these 156 days is approximately 75% of the estimated annual energy output. In addition, it is found that the inter-annual coefficient of variation of the global solar radiation is 4.28%, while that of diffuse radiation is 4.96%.

关键词: coefficient of variation     global solar radiation     diffuse ratio     albedo     PV energy systems    

REINTEGRATION OF CROP-LIVESTOCK SYSTEMS IN EUROPE: AN OVERVIEW

T. SCHUT, Emily C. COOLEDGE, Marc MORAINE, Gerrie W. J. VAN DE VEN, Davey L. JONES, David R.

《农业科学与工程前沿(英文)》 2021年 第8卷 第1期   页码 111-129 doi: 10.15302/J-FASE-2020373

摘要: Ongoing specialization of crop and livestock systems provides socioeconomic benefits to the farmer but has led to greater externalization of environmental costs when compared to mixed farming systems. Better integration of crop and livestock systems offers great potential to rebalance the economic and environmental trade-offs in both systems. The aims of this study were to analyze changes in farm structure and review and evaluate the potential for reintegrating specialized intensive crop and livestock systems, with specific emphasis on identifying the co-benefits and barriers to reintegration. Historically, animals were essential to recycle nutrients in the farming system but this became less important with the availability of synthetic fertilisers. Although mixed farm systems can be economically attractive, benefits of scale combined with socio-economic factors have resulted in on-farm and regional specialization with negative environmental impacts. Reintegration is therefore needed to reduce nutrient surpluses at farm, regional and national levels, and to improve soil quality in intensive cropping systems. Reintegration offers practical and cost-effective options to widen crop rotations and promotes the use of organic inputs and associated benefits, reducing dependency on synthetic fertilisers, biocides and manure processing costs. Circular agriculture goes beyond manure management and requires adaptation of both food production and consumption patterns, matching local capacity to produce with food demand. Consequently, feed transport, greenhouse gas emissions, nutrient surpluses and nutrient losses to the environment can be reduced. It is concluded that reintegration of specialized farms within a region can provide benefits to farmers but may also lead to further intensification of land use. New approaches within a food system context offer alternatives for reintegration, but require strong policy incentives which show clear, tangible and lasting benefits for farmers, the environment and the wider community.

关键词: circular agriculture     coupled farming systems     mixed farming     specialised farming systems     GHG    

Feedback linearization based control for weak grid connected PV system under normal and abnormal conditions

Rahul SHARMA,Sathans SUHAG

《能源前沿(英文)》 2020年 第14卷 第2期   页码 400-409 doi: 10.1007/s11708-017-0459-5

摘要: This paper proposes a control strategy for interface of distributed energy sources into the weak grid system with a focus on the energy and ancillary services. A novel controller has been designed and implemented to tackle the challenges of coupling terms in the LCL filter, the transient behavior under sudden changes, and the voltage support under fault condition using the feedback linearization technique. The controller proposed has been implemented on the PV system connected with the weak grid using the LCL filter and the performance of the controller has been verified using Matlab/Simulink through simulation under different conditions. The results of the controller proposed have been compared with the conventional PI dual loop controller. The simulation results obtained demonstrate the effectiveness and simplicity of the controller design strategy.

关键词: PV system     grid interface     feedback linearization     inverter     LCL filter    

HVAC系统的模糊预测函数控制器设计

吕红丽,贾磊,王雷,高瑞

《中国工程科学》 2006年 第8卷 第9期   页码 65-68

摘要:

针对暖通空调HVAC系统中由于存在高度非线性、时变特征以及扰动和不确定性等因素而难以控制的特点,提出基于Takagi-Sugeno(T-S)模糊模型的预测函数控制器设计方法。该方法通过最小二乘辨识算法建立系统的模糊T-S模型,然后基于模糊全局线性化预测模型,采用预测函数控制算法设计系统控制律。仿真实验结果表明该算法是一种跟踪性能好、鲁棒性强的有效控制方法。

关键词: T-S模糊模型     预测函数控制     最小二乘算法     HVAC系统    

Dynamic characteristics and improved MPPT control of PV generator

Houda BRAHMI, Rachid DHIFAOUI

《能源前沿(英文)》 2013年 第7卷 第3期   页码 342-350 doi: 10.1007/s11708-013-0242-1

摘要: This paper presents a mathematical model of photovoltaic (PV) module and gives a strategy to calculate online the maximum power point (MPP). The variation of series and shunt resistor are taken into account in the model and are dynamically identified using the Newton-Raphson algorithm. The effectiveness of the proposed model is verified by laboratory experiments obtained by implementing the model on the dSPACE DS1104 board.

关键词: modeling of photovoltaic (PV) generator     maximum power point tracking (MPPT)     estimation parameters     real time controller    

标题 作者 时间 类型 操作

Application of metal oxides-based nanofluids in PV/T systems: a review

期刊论文

PV/T太阳能热泵系统的性能研究

裴刚,季杰,何伟,孙炜

期刊论文

Performance enhancement of partially shaded solar PV array using novel shade dispersion technique

Namani RAKESH,T. Venkata MADHAVARAM

期刊论文

Requirements in performance measurement systems of construction projects from the lean production perspective

BARTH, Carlos T. FORMOSO

期刊论文

A new method for estimating the longevity and degradation of photovoltaic systems considering weather

Amir AHADI,Hosein HAYATI,Joydeep MITRA,Reza ABBASI-ASL,Kehinde AWODELE

期刊论文

Resiliency of steel and composite structures

Roberto T. LEON,Yu GAO

期刊论文

Fault classification and reconfiguration of distribution systems using equivalent capacity margin method

Sathish KUMAR, T. JAYABARATHI

期刊论文

Life cycle cost savings analysis on traditional drainage systems from low impact development strategies

Pengfei ZHANG, Samuel T. ARIARATNAM

期刊论文

State-of-art review of the optimization methods to design the configuration of hybrid renewable energy systems

Maurizio FACCIO, Mauro GAMBERI, Marco BORTOLINI, Mojtaba NEDAEI

期刊论文

Potential and economic viability of standalone hybrid systems for a rural community of Sokoto, North-west

O. D. OHIJEAGBON,Oluseyi. O AJAYI

期刊论文

Distribution and temporal variability of the solar resource at a site in south-east Norway

Muyiwa S. ADARAMOLA

期刊论文

REINTEGRATION OF CROP-LIVESTOCK SYSTEMS IN EUROPE: AN OVERVIEW

T. SCHUT, Emily C. COOLEDGE, Marc MORAINE, Gerrie W. J. VAN DE VEN, Davey L. JONES, David R.

期刊论文

Feedback linearization based control for weak grid connected PV system under normal and abnormal conditions

Rahul SHARMA,Sathans SUHAG

期刊论文

HVAC系统的模糊预测函数控制器设计

吕红丽,贾磊,王雷,高瑞

期刊论文

Dynamic characteristics and improved MPPT control of PV generator

Houda BRAHMI, Rachid DHIFAOUI

期刊论文