Power loss due to soiling on solar panel: a review

The power output delivered from a photovoltaic module highly depends on the amount of irradiance, which reaches the solar cells. Many factors determine the ideal output or optimum yield in a photovoltaic module. However, the environment is one of the contributing parameters which directly affect the photovoltaic performance. The authors review and evaluate key contributions to the understanding, performance effects, and mitigation of power loss due to soiling on a solar panel. Electrical characteristics of PV (Voltage and current) are discussed with respect to shading due to soiling. Shading due to soiling is divided in two categories, namely, soft shading such as air pollution, and hard shading which occurs when a solid such as accumulated dust blocks the sunlight. The result shows that soft shading affects the current provided by the PV module, but the voltage remains the same. In hard shading, the performance of the PV module depends on whether some cells are shaded or all cells of the PV module are shaded. If some cells are shaded, then as long as the unshaded cells receive solar irradiance, there will be some output although there will be a decrease in the voltage output of the PV module. This study also present a few cleaning method to prevent from dust accumulation on the surface of solar arrays

Third harmonic injection feedback to input technique for input current improvement in phase bridge rectifier

This paper schemed a circuit which applying active harmonic injection current with star connection of capacitors bank. The proposed circuit has a controller that regulates the synchronization of phase and injected appropriate harmonic waveform to reduce the harmonic components that appears in the three phase system. The aspirations of this paper were to propose and construct a three-phase rectifier with third harmonic injection current with regard to obtain an input current of three phase bridge rectifier of sinusoidal waveforms and produce low total harmonic distortion (THD). Consequently, the prototype of the three phase rectifier of the harmonic injection current is designed and fabricated. In this paper, in order to develop the method to obtain sinusoidal waveforms for input current, new method of harmonic injection in current is suggested. Experimental and simulation results have been compared. As a result, satisfactory similarities have been found in both ex periments and simulations. As a remarkable achievement, it has been proven that the suggested method is accurate

Qualitative and quantitative analysis of solar hydrogen generation literature from 2001 to 2014

Solar hydrogen generation is one of the new topics in the field of renewable energy. Recently, the rate of investigation about hydrogen generation is growing dramatically in many countries. Many studies have been done about hydrogen generation from natural resources such as wind, solar, coal etc. In this work we evaluated global scientific production of solar hydrogen generation papers from 2001 to 2014 in any journal of all the subject categories of the Science Citation Index compiled by Institute for Scientific Information (ISI), Philadelphia, USA. Solar hydrogen generation was used as keywords to search the parts of titles, abstracts, or keywords. The published output analysis showed that hydrogen generation from the sun research steadily increased over the past 14 years and the annual paper production in 2013 was about three times 2010-paper production. The number of papers considered in this research is 141 which have been published from 2001 to this date. There are clear distinctions among author keywords used in publications from the five most high-publishing countries such as USA, China, Australia, Germany and India in solar hydrogen studies. In order to evaluate this work quantitative and qualitative analysis methods were used to the development of global scientific production in a specific research field. The analytical results eventually provide several key findings and consider the overview hydrogen production according to the solar hydrogen generation

Hybrid renewable energy as power supply for shelter during natural disasters

People are very vulnerable in case of natural disasters. Power grid destruction is a common disaster in these situations. Numerous costumers might easily lose access to electric power and this condition can continue for a long time after the catastrophe. Emergency shelter after occurrence of disasters is usually offered by organizations or governmental emergency administration departments, as a comeback to natural disasters, such as an earthquake or flood. They tend to use tents or other temporary structures, or buildings. This paper focus on design of a Smart Hybrid power supply for shelter which is supported from three renewable energy source (wind, rain and solar) that is available in each condition in order to be used during emergency situation as a portable facility by analyzing the power generation ability and also the load demand characteristics during natural disaster for relief shelters

Increasing energy harvest of photovoltaic arrays under uniform illumination: a case study on photovoltaic arrays in Boulder CO and Tucson AZ

Studies on photovoltaic (PV) arrays have demonstrated that some arrays suffer from mismatch power losses even under uniform illumination. This mismatch power loss that is attributed to the inequality of characteristic parameters between a PV array's modules is conventionally addressed by sorting techniques - which stands for sorting PV modules in an array by one of their characteristic parameters such as Isc, IMPP or PMPP. Another recently suggested method to address this problem is arranging modules by genetic algorithm (GA). This paper applies this new technique to three PV arrays with relatively high mismatch losses. I-V curves for each array's modules are measured under different levels of radiation to provide a precise model. This precise modeling is used to run an annual simulation of energy yield and mismatch losses. Simulations carried out in this study show that a proper arrangement of modules in arrays decreases the mismatch losses and increases annual energy output more than what is gained by sorting techniques

Kriging and Latin hypercube sampling assisted simulation optimization in optimal design of PID controller for speed control of DC motor

Investigating less computationally expensive methods for achieving optimal tuning of proportional, integral, and derivative gains in PID controller also has become a main challenging topic in the world of control systems. This paper aims to propose a new less-expensive method to the optimal design of PID controller. For this purpose, Kriging metamodel is used with Latin Hypercube Sampling (LHS) as a common experimental design method in the class of space filling design. Kriging can interpolate over whole design space and assisted to investigate global optimum point. A numerical case in the tuning of PID controller for linear speed control of DC motor is served to show the applicability and superiority of proposed method compared to two existing methods such as traditional Zeigler-Nichols method and Taguchi-Grey Relational Analysis (Taguchi-GRA)

Integrated Network Analysis to Identify Key Modules and Potential Hub Genes Involved in Bovine Respiratory Disease: A Systems Biology Approach

Background: Bovine respiratory disease (BRD) is the most common disease in the beef and dairy cattle industry. BRD is a multifactorial disease resulting from the interaction between environmental stressors and infectious agents. However, the molecular mechanisms underlying BRD are not fully understood yet. Therefore, this study aimed to use a systems biology approach to systematically evaluate this disorder to better understand the molecular mechanisms responsible for BRD. Methods: Previously published RNA-seq data from whole blood of 18 healthy and 25 BRD samples were downloaded from the Gene Expression Omnibus (GEO) and then analyzed. Next, two distinct methods of weighted gene coexpression network analysis (WGCNA), i.e., module–trait relationships (MTRs) and module preservation (MP) analysis were used to identify significant highly correlated modules with clinical traits of BRD and non-preserved modules between healthy and BRD samples, respectively. After identifying respective modules by the two mentioned methods of WGCNA, functional enrichment analysis was performed to extract the modules that are biologically related to BRD. Gene coexpression networks based on the hub genes from the candidate modules were then integrated with protein–protein interaction (PPI) networks to identify hub–hub genes and potential transcription factors (TFs). Results: Four significant highly correlated modules with clinical traits of BRD as well as 29 non-preserved modules were identified by MTRs and MP methods, respectively. Among them, two significant highly correlated modules (identified by MTRs) and six nonpreserved modules (identified by MP) were biologically associated with immune response, pulmonary inflammation, and pathogenesis of BRD. After aggregation of gene coexpression networks based on the hub genes with PPI networks, a total of 307 hub–hub genes were identified in the eight candidate modules. Interestingly, most of these hub–hub genes were reported to play an important role in the immune response and BRD pathogenesis. Among the eight candidate modules, the turquoise (identified by MTRs) and purple (identified by MP) modules were highly biologically enriched in BRD. Moreover, STAT1, STAT2, STAT3, IRF7, and IRF9 TFs were suggested to play an important role in the immune system during BRD by regulating the coexpressed genes of these modules. Additionally, a gene set containing several hub–hub genes was identified in the eight candidate modules, such as TLR2, TLR4, IL10, SOCS3, GZMB, ANXA1, ANXA5, PTEN, SGK1, IFI6, ISG15, MX1, MX2, OAS2, IFIH1, DDX58, DHX58, RSAD2, IFI44, IFI44L, EIF2AK2, ISG20, IFIT5, IFITM3, OAS1Y, HERC5, and PRF1, which are potentially critical during infection with agents of bovine respiratory disease complex (BRDC). Conclusion: This study not only helps us to better understand the molecular mechanisms responsible for BRD but also suggested eight candidate modules along with several promising hub–hub genes as diagnosis biomarkers and therapeutic targets for BRD

Development of fuzzy logic for demand response and storage management in hybrid energy system

A Hybrid Energy System (HES) is a system that integrates multiple energy sources obtained by synchronizing energy output. Previous work has confirmed that HES in off-grid applications is economically viable, especially in remote areas. The energy management system (EMS) used in existing HESs are complicated, costly and less reliable this is because of over-or under unit sizing or mismatch between supply and demand, despite several improvements made over the last decade. The study was conducted to provide novel strategies for energy management of HESs by improving energy unit sizing and considering demand response program as well as storage management. The first objective of this thesis is to develop an existing computational model for optimising the sizing of micro-scale HES using Particle Swarm Optimisation (PSO). The second objective was to model and simulate an economic system in evaluating the performance and identifying the constraints in line with HES applications. Another objective of the study was to investigate the improvements that can be achieved in the storage management by minimising the mismatch between supply and demand during peak demand. The last objective was to design a real-time physical control system, by analysing the energy generation ability compared to load demand characteristics. The control unit should be able to be used in any weather condition. MATLAB Simulink software was used to model, simulate, and analyse the entire HES. The developed model was used to optimise the HES with an off-grid load. The constructed HES included a wind turbine, a hydro turbine, and a photovoltaic array, which were used as primary energy systems along with a compact battery as a backup energy system to supply continuous power to the load when the HES power was less than the load demand. Additionally, a Proton-exchange membrane fuel cells (PEMFC) was integrated into the system to harness excess energy from the hybrid system during the periods that the load demand was below the energy generation and the battery was fully charged. A Fuzzy Logic Controller (FLC) structure has been implemented in this system as the power management technique to control dispatch strategies and make optimum decisions. Due to the high cost of the energy storage system equipment, the combination of Energy Storage Management (DSM) and the Demand Side Management (DSM) was considered and subsequently, this could bring more reliability to the system. The experimental aspect of the research was conducted in the Nectar Lab in Serdang, Malaysia. A Programmable Logic Controller (PLC) was used for implementing, monitoring and controlling the HES, i.e. the Power Management Box. The design of the control panel unit was mainly aimed to control the dispatch between Generation, Demand and the backup system. The PLC controller, after receiving the data from all components via Remote IO, decided the best optimum operation mode for a specific location by considering the above objectives. The outcomes of this study, together with an economic analysis for a given system provide optimal costing and sizing for the planned system. The optimal cost of the system obtained in the economic analysis demonstrates that the system can be a good alternative for a grid isolated area and could be used as an off-grid system in areas of low demand

Dust material and mathematical relationship identification for photovoltaic systems

Photovoltaic (PV) systems are one of the next generation’s renewable energy sources for our world energy demand. PV modules are highly reliable. However, in polluted environments, over time, they will collect grime and dust. There are also limited field data studies about soiling losses on PV modules. This study is to investigate the effect of accumulated dust material on PV performance. The study includes two arrays of mini-modules. Each array has 12 PV modules tilted at 15º on the ground. The first array called "cleaned" was cleaned every week. The second array called "dusty" was never cleaned since the first day. Three types of data were required. The first type of data related to PV electrical characteristics. The second type related to environmental conditions, and the last type was associated with dust materials analysis. Required data were collected for eight months from April until first of December 2013. Due to a fault in the system, for 38 days there was no record of data and the final record was for a total of 209 days. Data from PV array and environmental data were collected with an online monitoring system and recorded every one minute over eight months. The data were analyzed to investigate the effect of dust on daily and monthly soiling, as well as transmitted solar insolation and energy production by PV modules. The main objective of this research is to conduct an experimental investigation on the effect of dust accumulated on the surface of PV array on output power in an open area where the effect of dust is unavoidable. For purposes of improvement, a mathematical relationship was predicted for the dust effect on PV generator performance. A comparative analysis was conducted to evaluate the effect of dust on PV array performance. The study shows that during the period of April through December 2013 there was an average loss due to soiling, of approximately 2.83% on dusty array. Comparing these two arrays for different months also was done and the results show that there are significant differences of output power among different months between the two arrays. Scatter plot was also employed for output power and environmental data to assess the relationship between the amount of output power generated from the dusty array and irradiation. The result shows that there was a positive correlation between the output power and irradiation variables, Correlation coefficient between thickness and power output indicated a moderate and negative relationship. Two mathematical relationship were predicted despite the dust thickness for dusty array and without dust, thickness for clean array and the validation of both prediction models was evaluated