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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)    

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    

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    

Sizing of hybrid PMSG-PV system for battery charging of electric vehicles

M. M. RAJAN SINGARAVEL,S. ARUL DANIEL

《能源前沿(英文)》 2015年 第9卷 第1期   页码 68-74 doi: 10.1007/s11708-015-0349-7

摘要: The number of electric vehicles are increasing in the society as they are considered as zero emission vehicles and also because conventional fuels are becoming expensive. Additional electrical power should be produced to meet the energy requirement of this increase in electric vehicle population. To use the existing grid infrastructure without any failure, installing distributed generator at secondary distribution network is essential. In this work, sizing of wind-driven permanent magnet synchronous generator—photovoltaic hybrid distributed generating system has been attempted to meet the energy demand of electric vehicles of a particular residential area. Different feasible combinations for wind generator capacity and photovoltaic capacity are obtained to satisfy the additional energy requirement. Results are analyzed based on energy, financial payback periods and daily power profile of the hybrid system. Based on this analysis, the sizes of wind generator and photovoltaic array have been chosen to meet the energy demand of electric vehicles of that particular residential locality.

关键词: electric vehicles     hybrid PMSG-PV system     smart grid    

Optimal design and development of PV-wind-battery based nano-grid system: A field-on-laboratory demonstration

B. TUDU, K. K. MANDAL, N. CHAKRABORTY

《能源前沿(英文)》 2019年 第13卷 第2期   页码 269-283 doi: 10.1007/s11708-018-0573-z

摘要: The present paper has disseminated the design approach, project implementation, and economics of a nano-grid system. The deployment of the system is envisioned to acculturate the renewable technology into Indian society by field-on-laboratory demonstration (FOLD) and “bridge the gaps between research, development, and implementation.” The system consists of a solar photovoltaic (PV) (2.4 kWp), a wind turbine (3.2 kWp), and a battery bank (400 Ah). Initially, a prefeasibility study is conducted using the well-established HOMER (hybrid optimization model for electric renewable) software developed by the National Renewable Energy Laboratory (NREL), USA. The feasibility study indicates that the optimal capacity for the nano-grid system consists of a 2.16 kWp solar PV, a 3 kWp wind turbine, a 1.44 kW inverter, and a 24 kWh battery bank. The total net present cost (TNPC) and cost of energy (COE) of the system are US$20789.85 and US$0.673/kWh, respectively. However, the hybrid system consisting of a 2.4 kWp of solar PV, a 3.2 kWp of wind turbine, a 3 kVA of inverter, and a 400 Ah of battery bank has been installed due to unavailability of system components of desired values and to enhance the reliability of the system. The TNPC and COE of the system installed are found to be US$20073.63 and US$0.635/kWh, respectively and both costs are largely influenced by battery cost. Besides, this paper has illustrated the installation details of each component as well as of the system. Moreover, it has discussed the detailed cost breakup of the system. Furthermore, the performance of the system has been investigated and validated with the simulation results. It is observed that the power generated from the PV system is quite significant and is almost uniform over the year. Contrary to this, a trivial wind velocity prevails over the year apart from the month of April, May, and June, so does the power yield. This research demonstration provides a pathway for future planning of scaled-up hybrid energy systems or microgrid in this region of India or regions of similar topography.

关键词: photovoltaic (PV)     wind     battery     nano-grid     hybrid optimization model for electric renewable (HOMER)     field-on-lab demonstration (FOLD)    

Rapid transaction to load variations of active filter supplied by PV system

M. BENADJA,S. SAAD,A. BELHAMRA

《能源前沿(英文)》 2014年 第8卷 第3期   页码 335-344 doi: 10.1007/s11708-014-0325-7

摘要: This paper deals with the analysis and control of a photovoltaic (PV) system connected to the main supply through a Boost converter and shunt active filter supplied by a PV system providing continuous supply of nonlinear load in variation. A robust control of a PV system connected to the grid while feeding a variable nonlinear load is developed and highlighted. This development is based on the control of the Boost converter to extract the maximum power from the PV system using the Perturb and Observe (P and O) algorithm in the presence of temperature and illumination. The proposed modeling and control strategy provide power to the variable nonlinear load and facilitates the transfer of power from solar panel to the grid while improving the quality of energy (harmonic currents compensation, power factor compensation and dc bus voltage regulation). Validation of the developed model and control strategy is conducted using power system simulator Sim-Power System Blockset Matlab/Simulink. To demonstrate the effectiveness of the shunt active filter to load changes, the method of instantaneous power ( theory) is used to identify harmonic currents. The obtained results show an accurate extraction of harmonic currents and perfect compensation of both reactive power and harmonic currents with a lower THD and in accordance with the IEEE-519 standard.

关键词: solar panels     maximum power point tracking (MPPT)     DC/DC converter (Boost)     shunt active filter     instantaneous power control     power quality     harmonics     imbalances     reactive energy    

Power quality investigation of a solar PV transformer-less grid- connected system fed DVR

Akhil GUPTA,Saurabh CHANANA,Tilak THAKUR

《能源前沿(英文)》 2014年 第8卷 第2期   页码 240-253 doi: 10.1007/s11708-014-0322-x

摘要: This paper presents a single stage transformer-less grid-connected solar photovoltaic (PV) system with an active and reactive power control. In the absence of active input power, the grid-tied voltage source converter (VSC) is operated in a reactive power generation mode, which powers the control circuitry, and maintains a regulated DC voltage to the VSC. A data-based maximum power point tracking (MPPT) control scheme which performs power quality control at a maximum power by reducing the total harmonic distortion (THD) in grid injected current as per IEEE-519/1547 standards is implemented. A proportional-integral (PI) controller based dynamic voltage restorer (DVR) control scheme is implemented which controls the grid side converter during single-phase to ground fault. The analysis includes the grid current THD along with the corresponding variation of the active and reactive power during the fault condition. The MPPT tracks the actual variable DC link voltage while deriving the maximum power from the solar PV array, and maintains the DC link voltage constant by changing the modulation index of the VSC. Simulation results using Matlab/Simulink are presented to demonstrate the feasibility and validations of the proposed novel MPPT and DVR control systems under different environmental conditions.

关键词: data-based maximum power point tracking (MPPT)     total harmonic distortion (THD)     proportional integral     control     voltage restorer     pulse width modulation    

A control scheme with performance prediction for a PV fed water pumping system

Ramesh K GOVINDARAJAN,Pankaj Raghav PARTHASARATHY,Saravana Ilango GANESAN

《能源前沿(英文)》 2014年 第8卷 第4期   页码 480-489 doi: 10.1007/s11708-014-0334-6

摘要: This paper focuses on modeling and performance predetermination of a photovoltaic (PV) system with a boost converter fed permanent magnet direct current (PMDC) motor-centrifugal pump load, taking the converter losses into account. Sizing is done based on the maximum power generated by the PV array at the average irradiation. Hence optimum sizing of the PV array for the given irradiation at the geographical location of interest is obtained using the predetermined values. The analysis presented here involves systems employing maximum power point tracking (MPPT) as they are more efficient than directly coupled systems. However, the voltage and power of the motor might rise above rated values for irradiations greater than the average when employing MPPT, hence a control scheme has been proposed to protect the PMDC motor from being damaged during these conditions. This control scheme appropriately chooses the optimum operating point of the system, ensuring long-term sustained operation. The numerical simulation of the system is performed in Matlab/Simulink and is validated with experimental results obtained from a 180 V, 0.5 hp PMDC motor coupled to a centrifugal pump. The operation of the system with the proposed control scheme is verified by varying the irradiation levels and the relevant results are presented.

关键词: photovoltaic system     boost converter     maximum power point tracking (MPPT)     DC permanent-magnet motor     centrifugal pump    

Emerging technologies to power next generation mobile electronic devices using solar energy

Dewei JIA , Yubo DUAN , Jing LIU ,

《能源前沿(英文)》 2009年 第3卷 第3期   页码 262-288 doi: 10.1007/s11708-009-0015-z

摘要: Mobile electronic devices such as MP3, mobile phones, and wearable or implanted medical devices have already or will soon become a necessity in peoples’ lives. However, the further development of these devices is restricted not only by the inconvenient charging process of the power module, but also by the soaring prices of fossil fuel and its downstream chain of electricity manipulation. In view of the huge amount of solar energy fueling the world biochemically and thermally, a carry-on electricity harvester embedded in portable devices is emerging as a most noteworthy research area and engineering practice for a cost efficient solution. Such a parasitic problem is intrinsic in the next generation portable devices. This paper is dedicated to presenting an overview of the photovoltaic strategy in the chain as a reference for researchers and practitioners committed to solving the problem.

关键词: photovoltaic conversion     energy harvesting     solar cell     maximum power point track algorithm     PV electricity storage     mobile/standalone PV application    

THD reduction with reactive power compensation for fuzzy logic DVR based solar PV grid connected system

Akhil GUPTA,Saurabh CHANANA,Tilak THAKUR

《能源前沿(英文)》 2014年 第8卷 第4期   页码 464-479 doi: 10.1007/s11708-014-0307-9

摘要: Dynamic voltage restorer (DVR) is used to protect sensitive loads from voltage disturbances of the distribution generation (DG) system. In this paper, a new control approach for the 200 kW solar photovoltaic grid connected system with perturb and observe maximum power point tracking (MPPT) technique is implemented. Power quality improvement with comparison is conducted during fault with proportional integral (PI) and artificial intelligence-based fuzzy logic controlled DVR. MPPT tracks the actual variable DC link voltage while deriving the maximum power from a photovoltaic array and maintains DC link voltage constant by changing modulation index of the converter. Simulation results during fault show that the fuzzy logic based DVR scheme demonstrates simultaneous exchange of active and reactive power with less total harmonic distortion (THD) present in voltage source converter (VSC) current and grid current with fast tracking of optimum operating point at unity power factor. Standards (IEEE-519/1547), stipulates that the current with THD greater than 5% cannot be injected into the grid by any distributed generation source. Simulation results and validations of MPPT technique and operation of fuzzy logic controlled DVR demonstrate the effectiveness of the proposed control schemes.

关键词: fuzzy logic     maximum power point tracking (MPPT)     proportional integral (PI)     control     voltage restorer    

Deubiquitinases as pivotal regulators of T cell functions

null

《医学前沿(英文)》 2018年 第12卷 第4期   页码 451-462 doi: 10.1007/s11684-018-0651-y

摘要:

T cells efficiently respond to foreign antigens to mediate immune responses against infections but are tolerant to self-tissues. Defect in T cell activation is associated with severe immune deficiencies, whereas aberrant T cell activation contributes to the pathogenesis of diverse autoimmune and inflammatory diseases. An emerging mechanism that regulates T cell activation and tolerance is ubiquitination, a reversible process of protein modification that is counter-regulated by ubiquitinating enzymes and deubiquitinases (DUBs). DUBs are isopeptidases that cleave polyubiquitin chains and remove ubiquitin from target proteins, thereby controlling the magnitude and duration of ubiquitin signaling. It is now well recognized that DUBs are crucial regulators of T cell responses and serve as potential therapeutic targets for manipulating immune responses in the treatment of immunological disorders and cancer. This review will discuss the recent progresses regarding the functions of DUBs in T cells.

关键词: deubiquitinase     ubiquitination     T cell activation     T cell differentiation     T cell tolerance    

Regulation of T cell immunity by cellular metabolism

null

《医学前沿(英文)》 2018年 第12卷 第4期   页码 463-472 doi: 10.1007/s11684-018-0668-2

摘要:

T cells are an important adaptive immune response arm that mediates cell-mediated immunity. T cell metabolism plays a central role in T cell activation, proliferation, differentiation, and effector function. Specific metabolic programs are tightly controlled to mediate T cell immune responses, and alterations in T cell metabolism may result in many immunological disorders. In this review, we will summarize the main T cell metabolic pathways and the important factors participating in T cell metabolic programming during T cell homeostasis, differentiation, and function.

关键词: T cell immunity     metabolic pathways     nutrient uptake     metabolic checkpoints    

Separation and extraction of bridge dynamic strain data

Baijian WU, Zhaoxia LI, Ying WANG, T. H. T. CHAN,

《结构与土木工程前沿(英文)》 2009年 第3卷 第4期   页码 395-400 doi: 10.1007/s11709-009-0049-7

摘要: Through comparing the measured data of dynamic strains due to loading and temperature by the stain gauge and temperature sensor at the same location, the information in the strain data was divided into three parts in the frequency domain by using the defined index named power spectral density (PSD)-ratio index. The three parts are dominated respectively by temperature varying, stresses, and noises and thus can be distinguished from the determined the separatrix frequencies. Also, a simple algorithm was developed to separate the three types of information and to extract the strain caused mainly by structural stresses. As an application of the proposed method, the effect of strain deformation and noises on the fatigue assessment was investigated based on the separated data. The results show that, the determined values of separatrix frequencies are valuable for the monitoring data from other bridges. The algorithm is a multiresolution and hierarchical method, which has been validated as a simple and effective method for data analyses, and is suitable for the compression and preprocessing of the great amount monitoring data and easy to be integrated into the structural health monitoring (SHM) soft system. The strain due to temperature varying attributes a little to the errors of fatigue assessment; however, the noises or random disturbance existed in the monitoring data have much responsibility for the errors, and the main reason is that the random disturbance shifts the real strain/stress amplitude picked up by real structural stress or strain.

关键词: dynamic     valuable     separatrix     strain/stress amplitude     frequency    

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

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

Rahul SHARMA,Sathans SUHAG

期刊论文

Dynamic characteristics and improved MPPT control of PV generator

Houda BRAHMI, Rachid DHIFAOUI

期刊论文

Sizing of hybrid PMSG-PV system for battery charging of electric vehicles

M. M. RAJAN SINGARAVEL,S. ARUL DANIEL

期刊论文

Optimal design and development of PV-wind-battery based nano-grid system: A field-on-laboratory demonstration

B. TUDU, K. K. MANDAL, N. CHAKRABORTY

期刊论文

Rapid transaction to load variations of active filter supplied by PV system

M. BENADJA,S. SAAD,A. BELHAMRA

期刊论文

Power quality investigation of a solar PV transformer-less grid- connected system fed DVR

Akhil GUPTA,Saurabh CHANANA,Tilak THAKUR

期刊论文

A control scheme with performance prediction for a PV fed water pumping system

Ramesh K GOVINDARAJAN,Pankaj Raghav PARTHASARATHY,Saravana Ilango GANESAN

期刊论文

Emerging technologies to power next generation mobile electronic devices using solar energy

Dewei JIA , Yubo DUAN , Jing LIU ,

期刊论文

THD reduction with reactive power compensation for fuzzy logic DVR based solar PV grid connected system

Akhil GUPTA,Saurabh CHANANA,Tilak THAKUR

期刊论文

Deubiquitinases as pivotal regulators of T cell functions

null

期刊论文

Regulation of T cell immunity by cellular metabolism

null

期刊论文

Separation and extraction of bridge dynamic strain data

Baijian WU, Zhaoxia LI, Ying WANG, T. H. T. CHAN,

期刊论文