Reverse-Osmosis Desalination of Water Powered by Photo-Voltaic Modules

The rising of the world’s population leads automatically to the rising of water demand. As a consequence the lack of drinking water increases. Currently, approximately 1.2 billion people globally (one-sixth of the world’s population) do not have access to adequate clean water. Since a large part of the world’s population is concentrated in coastal areas, the desalination of seawater seems to be a promising solution, especially in our Arab world. An innovative stand-alone solar desalination system could be used to produce drinking water from seawater or any brackish water sources. The great advantage of such a system is that it combines efficient desalination technology, reverse osmosis, with a renewable energy source;the main goal is improving the technical feasibility of such systems. There are many advantages of this coupling with RE resources;first of all we separate the drinking water from the electricity grid and its faults, save the burning fossil fuel and its emissions and can provide fresh water to remote communities that do not have sufficient traditional energy sources;but as we see in the thesis we don’t have economic benefit;because these projects depend on the electricity cost in each country and its location and its solar specifications. We design and implement a small laboratorial model for PV-RO (Photo-Voltaic Powered Reverse Osmosis) to recognize the its performance for seawater and brackish water;many of the problems are interrupted such as embargo on Syria;so we see this project has to be done according to affordable local potentialities, but we crave to keep the principle of operation, so we make it for the tap water which close to brackish.

Enhancing performance of low-temperature processed CsPbI2Br all-inorganic perovskite solar cells using polyethylene oxide-modified TiO_(2)

CsPbX_(3)-based(X=I,Br,Cl)inorganic perovskite solar cells(PSCs)prepared by low-temperature process have attracted much attention because of their low cost and excellent thermal stability.However,the high trap state density and serious charge recombination between low-temperature processed TiO_(2)film and inorganic perovskite layer interface seriously restrict the performance of all-inorganic PSCs.Here a thin polyethylene oxide(PEO)layer is employed to modify TiO_(2)film to passivate traps and promote carrier collection.The impacts of PEO layer on microstructure and photoelectric characteristics of TiO_(2)film and related devices are systematically studied.Characterization results suggest that PEO modification can reduce the surface roughness of TiO_(2)film,decrease its average surface potential,and passivate trap states.At optimal conditions,the champion efficiency of CsPbI_(2)Br PSCs with PEO-modified TiO_(2)(PEO-PSCs)has been improved to 11.24%from 9.03%of reference PSCs.Moreover,the hysteresis behavior and charge recombination have been suppressed in PEO-PSCs.

Evaluation of On-Line MPPT Algorithms for PV-Based Battery Storage Systems

This paper presents a novel Simulink models with an evaluation study of more widely used On-Line Maximum Power Point tracking(MPPT)techniques for Photo-Voltaic based Battery Storage Systems(PV-BSS).To have a full comparative study in terms of the dynamic response,battery state of charge(SOC),and oscillations around the Maximum Power Point(MPP)of the PV-BSS to variations in climate conditions,these techniques are simulated in Matlab/Simulink.The introduced methodologies are classified into two types;the first type is conventional hill-climbing techniques which are based on instantaneous PV data measurements such as Perturb&Observe and Incremental Conductance techniques.The second type is a novel proposed methodology is based on using solar irradiance and cell temperature measurements with pre-build Adaptive Neuro-Fuzzy Inference System(ANFIS)model to predict DC–DC converter optimum duty cycle to track MPP.Then evaluation study is introduced for conventional and proposed On-Line MPPT techniques.This comparative study can be useful in specifying the appropriateness of the MPPT techniques for PV-BSS.Also the introduced model can be used as a valued reference model for future research related to Soft Computing(SC)MPPT techniques.A significant improvement of SOC is achieved by the proposed model and methodology with high accuracy and lower oscillations.

Ce-Co-doped BiFeO_3 multiferroic for optoelectronic and photovoltaic applications

The Ce-Co-doped BiFeO3 multiferroic, Bi（1-x）Ce）xFe（1-x）CoxO3（x = 0.00, 0.01, 0.03, and 0.05）, has been prepared by a sol-gel auto-combustion method and analyzed through Raman spectroscopy, photoluminescence, and UV-visible spectroscopy. We have observed an anomalous intensity of the second-order Raman mode at - 1260 cm^-1 in pure BFO and suppressed intensity in doped samples, which indicates the presence of spin two-phonon coupling in these samples.The photoluminescence spectra show reduction in the intensity of emission with the increasing dopant concentration, which indicates the high charge separation efficiency. A sharp absorption with three charge transfer（C-T） and two d-d transitions are shown by UV-visible spectra in the visible region. The band gap of BiFeO3（BFO） is decreasing with increasing dopant concentrations and the materials are suitable for photovoltaic applications.

A Novel Asymmetrical Single-Phase Multilevel Inverter Suitable for Hybrid Renewable Energy Sources

This paper introduces a novel single-phase asymmetrical multilevel inverter suitable for hybrid renewable energy sources. The proposed inverter consists of two isolated DC sources and six power semiconductor controlled switches. The suggested inverter is capable of generating seven-level output when the input DC voltage is taken in the ratio of 1:2. The higher magnitude DC source is fed from Photo Voltaic (PV) panels, whereas the lower magnitude DC source is fed from Wind Turbine (WT) driven Permanent Magnet DC (PMDC) generator. Both the renewable energy sources are connected to the inverter via two DC-DC boost converters connected in cascade (i.e. one for maximum power point tracking and another for DC-link voltage control). The proposed hybrid renewable energy source inverter is connected to single-phase grid via proper control systems. The complete system is simulated using MATLAB/SIMULINK and the results are presented in detail.

HILLTOP RESIDENCE AND SITE SUSTAINABLE DESIGN

Sustainability on a residential renovation can be difficult to achieve.As this project was a complete gut renovation and two small additions,which included a new third story space,roof,and a rear addition,it was easy to investigate a wide variety of sustainable options.The building envelope was improved,interior aspects modified,and the energy generation systems explored and selected to all work in unison to enhance the end result of the project.In order to measure the degree of sustainability,ODG wanted to use a residential design rating system.At the time this house was designed there were few recognized residential rating systems available and none appeared to be as stringent and broad reaching as the LEED Commercial Rating system.ODG used the LEED 2.2 rating system as a guideline.When this project began,LEED for Homes had not yet been developed.The Hilltop Residence project sought to infuse an existing residence with the following qualities:cost effective technology,a“not to exceed”budget,a 75-year life cycle,the client’s aesthetics,functional living,sustainable design,and allow for productive healthy residents.ODG used the LEED categories of Sustainable Sites,Water Efficiency,Materials&Resources,Energy&Atmosphere,and Indoor Air Quality.The sustainable goals that were met affect both the building and the site.The home was designed to use rapidly renewable materials,use less water,conserve energy,generate its own electricity,automate the mechanical house processes,and reduce stormwater runoff.The renovated home conserved existing material and used new materials that are rapidly renewable.By designing to a 75-year life cycle,materials selected were either rapidly renewable or incredibly durable.Buildings designed for longer lifespans are inherently sustainable because their components will not need to be replaced as often.The reduction of operating and maintenance costs will pass savings directly to the client,providing a return on investment for the costs of the renovation and addition.By increasing the native vegetation,the site reduced runoff from the roof and decreased the amount of water being added to the storm sewer system.These goals,once realized and incorporated into the redesign of the townhome provide a clean,healthy indoor environment and highlight a residence with a climate responsive design and conservation practices.

Spatial and Temporal Variability of Solar Irradiance in Botswana

This study evaluated the potential of Botswana’s sustainable energy production using ERA5 reanalysis data of solar irradiance variability on an optimally inclined plane from 1971 to 2020. Spatial-temporal solar irradiance fluctuations were the focus of the study, and the relation to cloud cover and aerosol optical depth was investigated. The key findings suggest that the summer/rainfall season (November to March) is the peak season with average monthly solar irradiance of 313 - 445 W/m2 across southern, central, and northern parts of Botswana, the Kalahari Desert and the Makgadikgadi Pans being identified as prime sites for solar energy projects. The long-term trend analysis showed a decrease in solar irradiance in December but a consistent increase from August to October, indicating a potential shift in solar resources toward an earlier season. Contrary to other studies that found that aerosol optical depth dominates effects on long-term trends and year-to-year variability of solar irradiance, for this case, cloud cover, particularly mid-level clouds, is found to have a more dominant role in Botswana. Solar irradiance characteristics of three distinct regions were identified through K-means clustering. Moreover, Ensemble Empirical Mode Decomposition (EEMD) analysis showed the commonality and time scale linkage between solar irradiance and cloud cover between the identified regions. These results highlight the importance of including cloud-related weather patterns under the global warming scenario in solar energy planning and emphasize the secondary role of aerosols in Botswana, thus providing critical information for the region’s solar energy development and policy formulation.

CSI and CSI7 Current Source Inverters for Modular Transformerless PV Inverters

Current source inverter(CSI)is a class of power electronic converters that,thanks to the inherent boost capability and ease of control,is investigated for grid-tied photovoltaic power conversion applications.Traditional CSI and CSI7 topologies are here analyzed and compared with two kind of space vector modulation strategies mainly in terms of ground leakage current both in simulations and experiments.Furthermore,THD of the injected grid current and the computation of conduction and switching semiconductor power losses are also carried out in numerical simulations.The topology comparison is carried out with the use of a different number of PV modules,to analyze the robustness of the topologies to different size of the PV strings.Simulation and experimental results show that the CSI7 topology,with respect to conventional CSI,allows to strongly reduce ground leakage current,phase current THD and semicondutor power losses,at the price of an additional power device.

由原子薄横向异质结构建的可调谐肖特基二极管

本研究利用一步化学气相沉积技术制备了Sn_(x)Mo_(1−x)S_(2)/MoS_(2)横向异质结高性能二极管.通过选择性掺杂Sn原子到单层MoS_(2)的边缘,形成了与MoS_(2)相同晶格常数的Sn_(x)Mo_(1−x)S_(2).在边缘的Sn_(x)Mo_(1−x)S_(2)和内部的MoS_(2)上分别沉积铬/金电极,形成肖特基势垒,其中势垒高度不同导致载流子仅在一个方向上传输.通过控制掺杂浓度和栅极电压,可实现MoS_(2)和Sn_(x)Mo_(1−x)S_(2)之间费米能级的对齐调节,实现了可调整的整流比,最高达到104.令人印象深刻的是,该二极管还表现出优异的光伏特性,该器件在λ=400 nm处实现了40%的外量子效率值.此外,我们在无外部偏压条件下实现了自供电光电探测,该异质结二极管在400和650 nm波长处的响应率分别为0.12和0.16 A W^(-1).对应的探测率分别是4.9×10^(10)和6.4×10^(10)Jones.可调的掺杂浓度为进一步创造高效器件提供了可能.这种合成二维侧向二极管的策略丰富了异质结二极管的材料多样性,并为开发新型电子和光电器件提供了新的平台.

Assessment of a fuzzy logic based MRAS observer used in a photovoltaic array supplied AC drive

In this paper a fuzzy logic （FL） based model reference adaptive system （MRAS） speed observer for high performance AC drives is proposed. The error vector computation is made based on the rotor-flux derived from the reference and the adaptive model of the induction motor. The error signal is processed in the proposed fuzzy logic controller （FLC） for speed adaptation. The drive employs an indirect vector control scheme for achieving a good closed loop speed control. For powering the drive system, a standalone photovoltaic （PV） energy source is used. To extract the maximum power from the PV source, a constant voltage controller （CVC） is also proposed. The complete drive system is modeled in MATLAB/Simulink and the performance is analyzed for different operating conditions.

Modelling of electric vehicle charging station and controlled by fuzzy logic controller with different modes of operation

The main objective of implementing charging stations is to ensure the good charging to theElectric Vehicles by using a solar PV array which is interconnected to the battery energy storagesystems. The charging station regulates the supply voltage and frequency without the use of amechanical speed governor. It also assures that energy gained from grid or by the DG set willhave the unity power factor (UPF) when the load is nonlinear. Besides this, the Point of CommonCoupling (PCC) voltage is synchronised with the grid/generator voltage in order to providecontinuous charging. In order to increase the optimal efficiency of the charging stations, thecharging stations will perform the active/reactive power transfer from the vehicle to grid, vehicleto house and vehicle to vehicle (V2V) power transfer. The operational experiment of the chargingstation is simulated and verified by using MATLAB/SIMULINK.